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Apache NuttX RTOS for PinePhone

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![Apache NuttX RTOS on PinePhone](https://lupyuen.github.io/images/lvgl2-title.jpg)

# Apache NuttX RTOS for PinePhone

[![Daily Build of NuttX for PinePhone](https://github.com/lupyuen/pinephone-nuttx/actions/workflows/pinephone.yml/badge.svg)](https://github.com/lupyuen/pinephone-nuttx/actions/workflows/pinephone.yml)

Apache NuttX is a lightweight __Real-Time Operating System (RTOS)__ that runs on PINE64 PinePhone. Read the articles...

-   ["NuttX RTOS for PinePhone: What is it?"](https://lupyuen.github.io/articles/what)

[(Watch the Demo on YouTube)](https://youtu.be/kGI_0yK1vws)

-   ["NuttX RTOS for PinePhone: The First Year"](https://lupyuen.github.io/articles/pinephone2)

[(Watch the Presentation on Google Drive)](https://drive.google.com/file/d/1WL-6HVjhtqktHRmZiDbPCOs6934fQlEQ/view?usp=drive_link)

__PinePhone Display__

-   ["NuttX RTOS for PinePhone: MIPI Display Serial Interface"](https://lupyuen.github.io/articles/dsi3)

-   ["NuttX RTOS for PinePhone: Display Engine"](https://lupyuen.github.io/articles/de3)

__LCD Touch Panel__

-   ["NuttX RTOS for PinePhone: LCD Panel"](https://lupyuen.github.io/articles/lcd)

-   ["NuttX RTOS for PinePhone: Framebuffer"](https://lupyuen.github.io/articles/fb)

-   ["NuttX RTOS for PinePhone: Touch Panel"](https://lupyuen.github.io/articles/touch2)

__LVGL Graphics__

-   ["NuttX RTOS for PinePhone: Boot to LVGL"](https://lupyuen.github.io/articles/lvgl2)

-   ["NuttX RTOS for PinePhone: LVGL Terminal for NSH Shell"](https://lupyuen.github.io/articles/terminal)

-   ["(Possibly) LVGL in WebAssembly with Zig Compiler"](https://lupyuen.github.io/articles/lvgl3)

-   ["NuttX RTOS for PinePhone: Feature Phone UI in LVGL, Zig and WebAssembly"](https://lupyuen.github.io/articles/lvgl4)

__Accelerometer and Gyroscope__

-   ["Inside a Smartphone Accelerometer: PinePhone with NuttX RTOS"](https://www.hackster.io/lupyuen/inside-a-smartphone-accelerometer-pinephone-with-nuttx-rtos-b92b58)

__4G LTE Modem__

-   ["NuttX RTOS for PinePhone: 4G LTE Modem"](https://lupyuen.github.io/articles/lte)

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

__GPIO__

-   ["NuttX RTOS for PinePhone: Blinking the LEDs"](https://lupyuen.github.io/articles/pio)

__UART__

-   ["NuttX RTOS for PinePhone: UART Driver"](https://lupyuen.github.io/articles/serial)

__USB__

-   ["NuttX RTOS for PinePhone: Simpler USB with EHCI (Enhanced Host Controller Interface)"](https://lupyuen.github.io/articles/usb3)

-   ["NuttX RTOS for PinePhone: Exploring USB"](https://lupyuen.github.io/articles/usb2)

__Power Management Integrated Circuit__

-   ["Power Management Integrated Circuit (PMIC)"](https://lupyuen.github.io/articles/lcd#power-on-lcd-panel)

__Interrupts__

-   ["NuttX RTOS for PinePhone: Fixing the Interrupts"](https://lupyuen.github.io/articles/interrupt)

__Boot Sequence__

-   ["PinePhone Boots NuttX"](https://lupyuen.github.io/articles/unicorn2#pinephone-boots-nuttx)

-   ["PinePhone Continues Booting NuttX"](https://lupyuen.github.io/articles/unicorn2#pinephone-continues-booting-nuttx)

__Arm64 Emulation__

-   ["(Possibly) Emulate PinePhone with Unicorn Emulator"](https://lupyuen.github.io/articles/unicorn)

-   ["(Clickable) Call Graph for Apache NuttX Real-Time Operating System"](https://lupyuen.github.io/articles/unicorn2)

__Build and Boot NuttX__

-   ["Build Apache NuttX RTOS for PinePhone"](https://lupyuen.github.io/articles/lvgl2#appendix-build-apache-nuttx-rtos-for-pinephone)

-   ["Boot Apache NuttX RTOS on PinePhone"](https://lupyuen.github.io/articles/lvgl2#appendix-boot-apache-nuttx-rtos-on-pinephone)

__Download NuttX Binaries__

-   [Apache NuttX RTOS for PinePhone (Boot to LVGL Terminal)](https://github.com/lupyuen2/wip-pinephone-nuttx/releases/tag/nuttx-12.0.1)

-   [Apache NuttX RTOS for PinePhone (Boot to LVGL Demo)](https://github.com/lupyuen2/wip-pinephone-nuttx/releases/tag/nuttx-12.0.0)

__How It Started__

-   ["Apache NuttX RTOS on Arm Cortex-A53: How it might run on PinePhone"](https://lupyuen.github.io/articles/arm)

-   ["PinePhone boots Apache NuttX RTOS"](https://lupyuen.github.io/articles/uboot)

-   ["Preparing a Pull Request for Apache NuttX RTOS"](https://lupyuen.github.io/articles/pr)

__Older Articles__

-   ["Understanding PinePhone's Display (MIPI DSI)"](https://lupyuen.github.io/articles/dsi)

-   ["NuttX RTOS for PinePhone: Display Driver in Zig"](https://lupyuen.github.io/articles/dsi2)

-   ["Rendering PinePhone's Display (DE and TCON0)"](https://lupyuen.github.io/articles/de)

-   ["NuttX RTOS for PinePhone: Render Graphics in Zig"](https://lupyuen.github.io/articles/de2)

__Can AI Help?__

-   ["Apache NuttX RTOS trips ChatGPT"](https://lupyuen.github.io/articles/chatgpt)

_What's NuttX? Why run it on PinePhone?_

If we're new to NuttX, here's a gentle intro...

-   ["NuttX RTOS for PinePhone: What is it?"](https://lupyuen.github.io/articles/what)

The following is a journal that documents the porting of NuttX to PinePhone. It looks super messy and unstructured, please read the articles (at the top of this page) instead.

**Table of Contents**

- [NuttX Automated Daily Build for PinePhone](#nuttx-automated-daily-build-for-pinephone)
- [NuttX on QEMU](#nuttx-on-qemu)
  - [Download NuttX](#download-nuttx)
  - [Download Toolchain](#download-toolchain)
  - [Download QEMU](#download-qemu)
  - [Build NuttX: Single Core](#build-nuttx-single-core)
  - [Test NuttX with QEMU: Single Core](#test-nuttx-with-qemu-single-core)
  - [Build NuttX: Multi Core](#build-nuttx-multi-core)
  - [Test NuttX with QEMU: Multi Core](#test-nuttx-with-qemu-multi-core)
  - [Inside NuttX for Cortex-A53](#inside-nuttx-for-cortex-a53)
  - [NuttX Image](#nuttx-image)
  - [PinePhone Image](#pinephone-image)
  - [Will NuttX Boot On PinePhone?](#will-nuttx-boot-on-pinephone)
- [UART Driver for NuttX](#uart-driver-for-nuttx)
  - [Garbled Console Output](#garbled-console-output)
  - [Configure UART Port](#configure-uart-port)
  - [Test UART3 Port](#test-uart3-port)
- [Boot NuttX on PinePhone](#boot-nuttx-on-pinephone)
  - [PinePhone U-Boot Log](#pinephone-u-boot-log)
  - [NuttX Boots On PinePhone](#nuttx-boots-on-pinephone)
  - [NuttX Boot Log](#nuttx-boot-log)
- [Interrupt Controller](#interrupt-controller)
  - [Multi Core SMP](#multi-core-smp)
  - [System Timer](#system-timer)
  - [Timer Interrupt Isn't Handled](#timer-interrupt-isnt-handled)
  - [Arm64 Vector Table Is Wrong](#arm64-vector-table-is-wrong)
  - [Test PinePhone GIC with QEMU](#test-pinephone-gic-with-qemu)
  - [Handling Interrupts](#handling-interrupts)
  - [Dump Interrupt Vector Table](#dump-interrupt-vector-table)
  - [Interrupt Debugging](#interrupt-debugging)
  - [Memory Map](#memory-map)
  - [Boot Sequence](#boot-sequence)
  - [Boot Debugging](#boot-debugging)
  - [UART Interrupts](#uart-interrupts)
- [Backlight and LEDs](#backlight-and-leds)
  - [BASIC Blinks The LEDs](#basic-blinks-the-leds)
  - [NuttX Drivers for Allwinner A64 PIO and PinePhone LEDs](#nuttx-drivers-for-allwinner-a64-pio-and-pinephone-leds)
- [PinePhone Device Tree](#pinephone-device-tree)
  - [LCD Controller (TCON0)](#lcd-controller-tcon0)
  - [MIPI DSI Interface](#mipi-dsi-interface)
  - [Display PHY](#display-phy)
  - [Backlight PWM](#backlight-pwm)
  - [LED](#led)
  - [Framebuffer](#framebuffer)
  - [Display Engine](#display-engine)
  - [Touch Panel](#touch-panel)
  - [Video Codec](#video-codec)
  - [GPU](#gpu)
  - [Deinterlace](#deinterlace)
- [Zig on PinePhone](#zig-on-pinephone)
- [PinePhone Display Driver](#pinephone-display-driver)
  - [Zig Driver for PinePhone MIPI DSI](#zig-driver-for-pinephone-mipi-dsi)
  - [Compose MIPI DSI Long Packet in Zig](#compose-mipi-dsi-long-packet-in-zig)
  - [Compose MIPI DSI Short Packet in Zig](#compose-mipi-dsi-short-packet-in-zig)
  - [Compute Error Correction Code in Zig](#compute-error-correction-code-in-zig)
  - [Compute Cyclic Redundancy Check in Zig](#compute-cyclic-redundancy-check-in-zig)
  - [Test PinePhone MIPI DSI Driver with QEMU](#test-pinephone-mipi-dsi-driver-with-qemu)
  - [Test Case for PinePhone MIPI DSI Driver](#test-case-for-pinephone-mipi-dsi-driver)
  - [Initialise ST7703 LCD Controller in Zig](#initialise-st7703-lcd-controller-in-zig)
  - [Test Zig Display Driver for PinePhone](#test-zig-display-driver-for-pinephone)
  - [Display Engine in Allwinner A64](#display-engine-in-allwinner-a64)
  - [Display Engine Mixers](#display-engine-mixers)
  - [Render Colours](#render-colours)
  - [Render Mandelbrot Set](#render-mandelbrot-set)
  - [Animate Madelbrot Set](#animate-madelbrot-set)
  - [Render Square Overlay](#render-square-overlay)
  - [Render Circle Overlay](#render-circle-overlay)
  - [Test PinePhone Display Engine](#test-pinephone-display-engine)
  - [Display Engine Usage](#display-engine-usage)
  - [Other Display Engine Features](#other-display-engine-features)
  - [Timing Controller in Allwinner A64](#timing-controller-in-allwinner-a64)
  - [Zig Driver for PinePhone Display Engine](#zig-driver-for-pinephone-display-engine)
  - [Test Zig Driver for PinePhone Display Engine](#test-zig-driver-for-pinephone-display-engine)
  - [Complete PinePhone Display Driver in Zig](#complete-pinephone-display-driver-in-zig)
  - [Add MIPI DSI to NuttX Kernel](#add-mipi-dsi-to-nuttx-kernel)
  - [Test MIPI DSI for NuttX Kernel](#test-mipi-dsi-for-nuttx-kernel)
  - [Test Timing Controller TCON0 Driver for NuttX Kernel](#test-timing-controller-tcon0-driver-for-nuttx-kernel)
  - [Test Display Engine Driver for NuttX Kernel](#test-display-engine-driver-for-nuttx-kernel)
  - [Missing Pixels in PinePhone Image](#missing-pixels-in-pinephone-image)
  - [Fix Missing Pixels in PinePhone Image](#fix-missing-pixels-in-pinephone-image)
- [Merge PinePhone into NuttX Mainline](#merge-pinephone-into-nuttx-mainline)
- [LVGL on NuttX on PinePhone](#lvgl-on-nuttx-on-pinephone)
  - [LVGL Settings for PinePhone](#lvgl-settings-for-pinephone)
  - [LVGL Demos on PinePhone](#lvgl-demos-on-pinephone)
  - [Boot to LVGL on PinePhone](#boot-to-lvgl-on-pinephone)
- [PinePhone Touch Panel](#pinephone-touch-panel)
  - [Handle Interrupts from Touch Panel](#handle-interrupts-from-touch-panel)
  - [NuttX Touch Panel Driver for PinePhone](#nuttx-touch-panel-driver-for-pinephone)
- [LVGL Terminal for NuttX](#lvgl-terminal-for-nuttx)
  - [Pipe a Command to NuttX NSH Shell](#pipe-a-command-to-nuttx-nsh-shell)
  - [Poll for NSH Output](#poll-for-nsh-output)
  - [Timer for LVGL Terminal](#timer-for-lvgl-terminal)
  - [Poll for NSH Output in LVGL Timer](#poll-for-nsh-output-in-lvgl-timer)
  - [Render Terminal with LVGL Widgets](#render-terminal-with-lvgl-widgets)
  - [Set LVGL Terminal Font to Monospace](#set-lvgl-terminal-font-to-monospace)
  - [Handle Input from LVGL Keyboard](#handle-input-from-lvgl-keyboard)
  - [Handle Output from NSH Shell](#handle-output-from-nsh-shell)
- [PinePhone on NuttX becomes a Feature Phone](#pinephone-on-nuttx-becomes-a-feature-phone)
- [USB Driver and LTE Modem Driver for PinePhone](#usb-driver-and-lte-modem-driver-for-pinephone)
- [4G LTE Modem](#4g-lte-modem)
  - [Outgoing Phone Call](#outgoing-phone-call)
  - [Send SMS in Text Mode](#send-sms-in-text-mode)
  - [Send SMS in PDU Mode](#send-sms-in-pdu-mode)
  - [SMS PDU Format](#sms-pdu-format)
  - [SMS Text Mode vs PDU Mode](#sms-text-mode-vs-pdu-mode)
- [PinePhone Accelerometer and Gyroscope](#pinephone-accelerometer-and-gyroscope)
- [Compile NuttX on Android with Termux](#compile-nuttx-on-android-with-termux)
- [Emulate PinePhone with Unicorn Emulator](#emulate-pinephone-with-unicorn-emulator)
- [Simulate PinePhone UI with Zig, LVGL and WebAssembly](#simulate-pinephone-ui-with-zig-lvgl-and-webassembly)
- [Apache NuttX RTOS for PinePhone Pro](#apache-nuttx-rtos-for-pinephone-pro)
- [Test Logs](#test-logs)
  - [USB Devices on PinePhone](#usb-devices-on-pinephone)
  - [Testing Zig Backlight Driver on PinePhone](#testing-zig-backlight-driver-on-pinephone)
  - [Testing Zig Display Engine Driver on PinePhone](#testing-zig-display-engine-driver-on-pinephone)
  - [Testing Zig Display Engine Driver on QEMU](#testing-zig-display-engine-driver-on-qemu)
  - [Testing p-boot Display Engine on PinePhone](#testing-p-boot-display-engine-on-pinephone)
  - [Testing NuttX Zig Driver for MIPI DSI on PinePhone](#testing-nuttx-zig-driver-for-mipi-dsi-on-pinephone)
  - [Testing NuttX Zig Driver for MIPI DSI on QEMU](#testing-nuttx-zig-driver-for-mipi-dsi-on-qemu)
  - [Testing p-boot Driver for MIPI DSI (with logging)](#testing-p-boot-driver-for-mipi-dsi-with-logging)
  - [Testing p-boot Driver for MIPI DSI (without logging)](#testing-p-boot-driver-for-mipi-dsi-without-logging)
  - [Testing Zig on PinePhone](#testing-zig-on-pinephone)
  - [Testing GIC Version 2 on PinePhone](#testing-gic-version-2-on-pinephone)
  - [Testing GIC Version 2 on QEMU](#testing-gic-version-2-on-qemu)
  - [Boot Files for Manjaro Phosh on PinePhone](#boot-files-for-manjaro-phosh-on-pinephone)
  - [GIC Register Dump](#gic-register-dump)

# NuttX Automated Daily Build for PinePhone

NuttX for PinePhone is now built automatically every day via GitHub Actions.

The Daily Releases are available here...

- [pinephone-nuttx/releases](https://github.com/lupyuen/pinephone-nuttx/releases)

[nuttx.hash](https://github.com/lupyuen/pinephone-nuttx/releases/download/pinephone-nuttx-2023-08-12/nuttx.hash) contains the Commit Hash of the NuttX Kernel and NuttX Apps repos...

```text
NuttX Source: https://github.com/apache/nuttx/tree/4bb30ab0c136dc36182cf43995337fc1d44f0a37
NuttX Apps: https://github.com/apache/nuttx-apps/tree/5a4e9e4389264522d02dae78bcb3f9813743300f
```

The GitHub Actions Workflow is here...

- [pinephone.yml](https://github.com/lupyuen/pinephone-nuttx/blob/main/.github/workflows/pinephone.yml)

# NuttX on QEMU

Note: This section is outdated, please check this article for updates...

-   ["Apache NuttX RTOS on Arm Cortex-A53: How it might run on PinePhone"](https://lupyuen.github.io/articles/arm)

[Apache NuttX RTOS](https://nuttx.apache.org/docs/latest/) now runs on Arm Cortex-A53 with Multi-Core SMP...

-   [nuttx/boards/arm64/qemu/qemu-a53](https://github.com/apache/incubator-nuttx/tree/master/boards/arm64/qemu/qemu-a53)

PinePhone is based on [Allwinner A64 SoC](https://linux-sunxi.org/A64) with 4 Cores of Arm Cortex-A53...

-   [PinePhone Wiki](https://wiki.pine64.org/index.php/PinePhone)

We start with NuttX Mainline, run it on QEMU, then mod it for PinePhone.

## Download NuttX

Download the Source Code for NuttX Mainline, which supports Arm Cortex-A53...

```bash
## Create NuttX Directory
mkdir nuttx
cd nuttx

## Download NuttX OS
git clone \
    --recursive \
    --branch arm64 \
    https://github.com/lupyuen/incubator-nuttx \
    nuttx

## Download NuttX Apps
git clone \
    --recursive \
    --branch arm64 \
    https://github.com/lupyuen/incubator-nuttx-apps \
    apps

## We'll build NuttX inside nuttx/nuttx
cd nuttx
```

Install the Build Prerequisites, skip the RISC-V Toolchain...

-   ["Install Prerequisites"](https://lupyuen.github.io/articles/nuttx#install-prerequisites)

## Download Toolchain

Download the Arm Toolchain for AArch64 ELF Bare-Metal Target (`aarch64-none-elf`)...

-   [Arm GNU Toolchain Downloads](https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads)

For Linux x64 and WSL:

-   [gcc-arm-11.2-2022.02-x86_64-aarch64-none-elf.tar.xz](https://developer.arm.com/-/media/Files/downloads/gnu/11.2-2022.02/binrel/gcc-arm-11.2-2022.02-x86_64-aarch64-none-elf.tar.xz)

For macOS:

-   [arm-gnu-toolchain-11.3.rel1-darwin-x86_64-aarch64-none-elf.pkg](https://developer.arm.com/-/media/Files/downloads/gnu/11.3.rel1/binrel/arm-gnu-toolchain-11.3.rel1-darwin-x86_64-aarch64-none-elf.pkg)

(I don't recommend building NuttX on Plain Old Windows CMD, please use WSL instead)

Add it to the `PATH`...

```bash
## For Linux x64 and WSL:
export PATH="$PATH:$HOME/gcc-arm-11.2-2022.02-x86_64-aarch64-none-elf/bin"

## For macOS:
export PATH="$PATH:/Applications/ArmGNUToolchain/11.3.rel1/aarch64-none-elf/bin"
```

Check the toolchain...

```bash
aarch64-none-elf-gcc -v
```

[(Based on the instructions here)](https://github.com/apache/incubator-nuttx/tree/master/boards/arm64/qemu/qemu-a53)

## Download QEMU

Download and install QEMU...

-   [Download QEMU](https://www.qemu.org/download/)

For macOS we may use `brew`...

```bash
brew install qemu
```

## Build NuttX: Single Core

First we build NuttX for a Single Core of Arm Cortex-A53...

```bash
## Configure NuttX for Single Core
./tools/configure.sh -l qemu-a53:nsh

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

The NuttX Output Files may be found here...

-   [NuttX for Arm Cortex-A53 Single Core](https://github.com/lupyuen/pinephone-nuttx/releases/tag/v1.0.1)

## Test NuttX with QEMU: Single Core

This is how we test NuttX on QEMU with a Single Core of Arm Cortex-A53...

```bash
## Start QEMU (Single Core) with NuttX
qemu-system-aarch64 \
  -cpu cortex-a53 \
  -nographic \
  -machine virt,virtualization=on,gic-version=3 \
  -net none \
  -chardev stdio,id=con,mux=on \
  -serial chardev:con \
  -mon chardev=con,mode=readline \
  -kernel ./nuttx
```

Here's NuttX with a Single Core running on QEMU...

```text
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

nx_start: Entry
up_allocate_heap: heap_start=0x0x402c4000, heap_size=0x7d3c000
gic_validate_dist_version: GICv3 version detect
gic_validate_dist_version: GICD_TYPER = 0x37a0007
gic_validate_dist_version: 224 SPIs implemented
gic_validate_dist_version: 0 Extended SPIs implemented
gic_validate_dist_version: Distributor has no Range Selector support
gic_validate_redist_version: GICD_TYPER = 0x1000011
gic_validate_redist_version: 16 PPIs implemented
gic_validate_redist_version: no VLPI support, no direct LPI support
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 62.50MHz, cycle 62500
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x402a7000 _einit: 0x402a7000 _stext: 0x40280000 _etext: 0x402a8000
nsh: sysinit: fopen failed: 2
nsh: mkfatfs: command not found

NuttShell (NSH) NuttX-10.3.0-RC2
nsh> nx_start: CPU0: Beginning Idle Loop

nsh> help
help usage:  help [-v] [<cmd>]

.         cd        dmesg     help      mount     rmdir     true      xd        
  [         cp        echo      hexdump   mv        set       truncate  
  ?         cmp       exec      kill      printf    sleep     uname     
  basename  dirname   exit      ls        ps        source    umount    
  break     dd        false     mkdir     pwd       test      unset     
  cat       df        free      mkrd      rm        time      usleep

Builtin Apps:
  getprime  hello     nsh       ostest    sh

nsh> uname -a
NuttX 10.3.0-RC2 1e8f2a8 Aug 23 2022 07:04:54 arm64 qemu-a53

nsh> hello
task_spawn: name=hello entry=0x4029b594 file_actions=0x402c9580 attr=0x402c9588 argv=0x402c96d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
Hello, World!!

nsh> ls /
/:
 dev/
 etc/
 proc/

nsh> ls /dev
/dev:
 console
 null
 ram0
 ram2
 ttyS0
 zero

nsh> ls /proc
/proc:
 0/
 1/
 2/
 meminfo
 memdump
 fs/
 self/
 uptime
 version

nsh> ls /etc
/etc:
 init.d/

nsh> ls /etc/init.d
/etc/init.d:
 rcS

nsh> cat /etc/init.d/rcS
# Create a RAMDISK and mount it at /tmp

mkrd -m 2 -s 512 1024
mkfatfs /dev/ram2
mount -t vfat /dev/ram2 /tmp
```

NuttX is [POSIX Compliant](https://nuttx.apache.org/docs/latest/introduction/inviolables.html), so the developer experience feels very much like Linux. (But much smaller)

And NuttX runs everything in RAM, no File System needed. (For now)

## Build NuttX: Multi Core

From Single Core to Multi Core! Now we build NuttX for 4 Cores of Arm Cortex-A53...

```bash
## Erase the NuttX Configuration
make distclean

## Configure NuttX for 4 Cores
./tools/configure.sh -l qemu-a53:nsh_smp

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

The NuttX Output Files may be found here...

-   [NuttX for Arm Cortex-A53 Multi-Core](https://github.com/lupyuen/pinephone-nuttx/releases/tag/v1.0.0)

## Test NuttX with QEMU: Multi Core

And this is how we test NuttX on QEMU with 4 Cores of Arm Cortex-A53...

```bash
## Start QEMU (4 Cores) with NuttX
qemu-system-aarch64 \
  -smp 4 \
  -cpu cortex-a53 \
  -nographic \
  -machine virt,virtualization=on,gic-version=3 \
  -net none \
  -chardev stdio,id=con,mux=on \
  -serial chardev:con \
  -mon chardev=con,mode=readline \
  -kernel ./nuttx
```

Note that `smp` is set to 4. [(Symmetric Multi-Processing)](https://developer.arm.com/documentation/den0024/a/Multi-core-processors/Multi-processing-systems/Symmetric-multi-processing?lang=en)

Here's NuttX with 4 Cores running on QEMU...

```text
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

[CPU0] psci_detect: Detected PSCI v1.1
[CPU0] nx_start: Entry
[CPU0] up_allocate_heap: heap_start=0x0x402db000, heap_size=0x7d25000
[CPU0] gic_validate_dist_version: GICv3 version detect
[CPU0] gic_validate_dist_version: GICD_TYPER = 0x37a0007
[CPU0] gic_validate_dist_version: 224 SPIs implemented
[CPU0] gic_validate_dist_version: 0 Extended SPIs implemented
[CPU0] gic_validate_dist_version: Distributor has no Range Selector support
[CPU0] gic_validate_redist_version: GICD_TYPER = 0x1000001
[CPU0] gic_validate_redist_version: 16 PPIs implemented
[CPU0] gic_validate_redist_version: no VLPI support, no direct LPI support
[CPU0] up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 62.50MHz, cycle 62500
[CPU0] uart_register: Registering /dev/console
[CPU0] uart_register: Registering /dev/ttyS0

- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

[CPU1] gic_validate_redist_version: GICD_TYPER = 0x101000101
[CPU1] gic_validate_redist_version: 16 PPIs implemented
[CPU1] gic_validate_redist_version: no VLPI support, no direct LPI support
[CPU1] nx_idle_trampoline: CPU1: Beginning Idle Loop
[CPU0] arm64_start_cpu: Secondary CPU core 1 (MPID:0x1) is up

- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

[CPU2] gic_validate_redist_version: GICD_TYPER = 0x201000201
[CPU2] gic_validate_redist_version: 16 PPIs implemented
[CPU2] gic_validate_redist_version: no VLPI support, no direct LPI support
[CPU2] nx_idle_trampoline: CPU2: Beginning Idle Loop
[CPU0] arm64_start_cpu: Secondary CPU core 2 (MPID:0x2) is up

- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize

[CPU3] gic_validate_redist_version: GICD_TYPER = 0x301000311
[CPU3] gic_validate_redist_version: 16 PPIs implemented
[CPU3] gic_validate_redist_version: no VLPI support, no direct LPI support
[CPU0] arm64_start_cpu: Secondary CPU core 3 (MPID:0x3) is up
[CPU0] work_start_highpri: Starting high-priority kernel worker thread(s)
[CPU0] nx_start_application: Starting init thread
[CPU3] nx_idle_trampoline: CPU3: Beginning Idle Loop
[CPU0] nx_start: CPU0: Beginning Idle Loop

nsh: sysinit: fopen failed: 2
nsh: mkfatfs: command not found

NuttShell (NSH) NuttX-10.3.0-RC2
nsh> help
help usage:  help [-v] [<cmd>]

Builtin Apps:
  getprime  hello     nsh       ostest    sh        smp       taskset

nsh> uname -a
NuttX 10.3.0-RC2 1e8f2a8 Aug 21 2022 15:57:35 arm64 qemu-a53

nsh> hello
[CPU0] task_spawn: name=hello entry=0x4029cee4 file_actions=0x402e52b0 attr=0x402e52b8 argv=0x402e5400
[CPU0] spawn_execattrs: Setting policy=2 priority=100 for pid=6
Hello, World!
```

We see each of the 4 Cores starting NuttX (CPU0 to CPU3). That's so cool!

(Can we use QEMU to partially emulate PinePhone? That would be extremely helpful!)

## Inside NuttX for Cortex-A53

Now we browse the Source Files for the implementation of Cortex-A53 on NuttX.

NuttX treats QEMU as a Target Board (as though it was a dev board). Here are the Source Files and Build Configuration for the QEMU Board...

-   [nuttx/boards/arm64/qemu/qemu-a53](https://github.com/apache/incubator-nuttx/tree/master/boards/arm64/qemu/qemu-a53)

(We'll clone this to create a Target Board for PinePhone)

The Board-Specific Drivers for QEMU are started in [qemu-a53/src/qemu_bringup.c](https://github.com/apache/incubator-nuttx/blob/master/boards/arm64/qemu/qemu-a53/src/qemu_bringup.c)

(We'll start the PinePhone Drivers here)

The QEMU Board calls the QEMU Architecture-Specific Drivers at...

-   [nuttx/arch/arm64/src/qemu](https://github.com/apache/incubator-nuttx/tree/master/arch/arm64/src/qemu)

The UART Driver is located at [qemu/qemu_serial.c](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/qemu/qemu_serial.c) and [qemu/qemu_lowputc.S](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/qemu/qemu_lowputc.S)

(For PinePhone we'll create a UART Driver for Allwinner A64 SoC. I2C, SPI and other Low-Level A64 Drivers will be located here too)

The QEMU Functions (Board and Architecture) call the Arm64 Architecture Functions at...

-   [nuttx/arch/arm64/src/common](https://github.com/apache/incubator-nuttx/tree/master/arch/arm64/src/common)

Which implements all kinds of Arm64 Features: [FPU](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/common/arm64_fpu.c), [Interrupts](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/common/arm64_gicv3.c), [MMU](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/common/arm64_mmu.c), [Tasks](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/common/arm64_task_sched.c), [Timers](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/common/arm64_arch_timer.c)...

(We'll reuse them for PinePhone)

## NuttX Image

Next we analyse the NuttX Image with [Ghidra](https://ghidra-sre.org/), to understand the NuttX Image Header and Startup Code.

Here's the [NuttX ELF Image `nuttx`](https://github.com/lupyuen/pinephone-nuttx/releases/download/v1.0.0/nuttx) analysed by Ghidra...

![Ghidra with Apache NuttX RTOS for Arm Cortex-A53](https://lupyuen.github.io/images/arm-ghidra1.png)

Note that the NuttX Image jumps to `real_start` (to skip the Image Header)...

```text
40280000 4d 5a 00 91     add        x13,x18,#0x16
40280004 0f 00 00 14     b          real_start
```

`real_start` is defined at 0x4028 0040 with the Startup Code...

![Bottom Part of NuttX Image Header](https://lupyuen.github.io/images/arm-title.png)

We see something interesting: The Magic Number `ARM\x64` appears at address 0x4028 0038.

Searching the net for this Magic Number reveals that it's actually an Arm64 Linux Kernel Header!

When we refer to the [NuttX Arm64 Disassembly `nuttx.S`](https://github.com/lupyuen/pinephone-nuttx/releases/download/v1.0.0/nuttx.S), we find happiness: [arch/arm64/src/common/arm64_head.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L79-L117)

```text
    /* Kernel startup entry point.
     * ---------------------------
     *
     * The requirements are:
     *   MMU = off, D-cache = off, I-cache = on or off,
     *   x0 = physical address to the FDT blob.
     *       it will be used when NuttX support device tree in the future
     *
     * This must be the very first address in the loaded image.
     * It should be loaded at any 4K-aligned address.
     */
    .globl __start;
__start:

/* DO NOT MODIFY. Image header expected by Linux boot-loaders.
     *
     * This add instruction has no meaningful effect except that
     * its opcode forms the magic "MZ" signature of a PE/COFF file
     * that is required for UEFI applications.
     *
     * Some bootloader (such imx8 uboot) checking the magic "MZ" to see
     * if the image is a valid Linux image. but modifying the bootLoader is
     * unnecessary unless we need to do a customize secure boot.
     * so just put the ''MZ" in the header to make bootloader happiness
     */

add     x13, x18, #0x16      /* the magic "MZ" signature */
    b       real_start           /* branch to kernel start */
    .quad   0x480000              /* Image load offset from start of RAM */
    .quad   _e_initstack - __start         /* Effective size of kernel image, little-endian */
    .quad   __HEAD_FLAGS         /* Informative flags, little-endian */
    .quad   0                    /* reserved */
    .quad   0                    /* reserved */
    .quad   0                    /* reserved */
    .ascii  "ARM\x64"            /* Magic number, "ARM\x64" */
    .long   0                    /* reserved */

real_start:
    /* Disable all exceptions and interrupts */
```

NuttX Image actually follows the Arm64 Linux Kernel Image Format! As defined here...

-   ["Booting AArch64 Linux"](https://www.kernel.org/doc/html/latest/arm64/booting.html)

Arm64 Linux Kernel Image contains a 64-byte header...

```text
u32 code0;                    /* Executable code */
u32 code1;                    /* Executable code */
u64 text_offset;              /* Image load offset, little endian */
u64 image_size;               /* Effective Image size, little endian */
u64 flags;                    /* kernel flags, little endian */
u64 res2      = 0;            /* reserved */
u64 res3      = 0;            /* reserved */
u64 res4      = 0;            /* reserved */
u32 magic     = 0x644d5241;   /* Magic number, little endian, "ARM\x64" */
u32 res5;                     /* reserved (used for PE COFF offset) */
```

Start of RAM is 0x4000 0000. The Image Load Offset in our NuttX Image Header is 0x48 0000 according to [arch/arm64/src/common/arm64_head.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L107)

```text
    .quad   0x480000              /* Image load offset from start of RAM */
```

This means that our NuttX Image will be loaded at 0x4048 0000.

I wonder if this Image Load Offset should have been 0x28 0000? (Instead of 0x48 0000)

Remember that Ghidra (and the Arm Disassembly) says that our NuttX Image is actually loaded at 0x4028 0000. (Instead of 0x4048 0000)

RAM Size and RAM Start are defined in the NuttX Configuration: [boards/arm64/qemu/qemu-a53/configs/nsh_smp/defconfig](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/boards/arm64/qemu/qemu-a53/configs/nsh_smp/defconfig#L47-L48)

```text
CONFIG_RAM_SIZE=134217728
CONFIG_RAM_START=0x40000000
```

That's 128 MB RAM. Which should fit inside PinePhone's 2 GB RAM.

The NuttX Image was built with this Linker Command, based on `make --trace`...

```bash
aarch64-none-elf-ld \
  --entry=__start \
  -nostdlib \
  --cref \
  -Map=nuttx/nuttx/nuttx.map \
  -Tnuttx/nuttx/boards/arm64/qemu/qemu-a53/scripts/dramboot.ld  \
  -L nuttx/nuttx/staging \
  -L nuttx/nuttx/arch/arm64/src/board  \
  -o nuttx/nuttx/nuttx arm64_head.o  \
  --start-group \
  -lsched \
  -ldrivers \
  -lboards \
  -lc \
  -lmm \
  -larch \
  -lapps \
  -lfs \
  -lbinfmt \
  -lboard /Applications/ArmGNUToolchain/11.3.rel1/aarch64-none-elf/bin/../lib/gcc/aarch64-none-elf/11.3.1/libgcc.a /Applications/ArmGNUToolchain/11.3.rel1/aarch64-none-elf/bin/../lib/gcc/aarch64-none-elf/11.3.1/../../../../aarch64-none-elf/lib/libm.a \
  --end-group
```

NuttX Image begins at `__start`, which is defined as 0x4028 0000 in the NuttX Linker Script: [boards/arm64/qemu/qemu-a53/scripts/dramboot.ld](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/boards/arm64/qemu/qemu-a53/scripts/dramboot.ld#L30-L33)

```text
SECTIONS
{
  . = 0x40280000;  /* uboot load address */
  _start = .;
```

We'll change this to 0x4008 0000 for PinePhone, since Kernel Start Address is 0x4008 0000 and Image Load Offset is 0. (See below)

We've seen the NuttX Image (which looks like a Linux Kernel Image), let's compare with a PinePhone Linux Kernel Image and see how NuttX needs to be tweaked...

## PinePhone Image

Will NuttX run on PinePhone? Let's analyse a PinePhone Linux Kernel Image with Ghidra, to look at the Linux Kernel Header and Startup Code.

We'll use the PinePhone Jumpdrive Image, since it's small...

https://github.com/dreemurrs-embedded/Jumpdrive

Download https://github.com/dreemurrs-embedded/Jumpdrive/releases/download/0.8/pine64-pinephone.img.xz

Expand `pine64-pinephone.img.xz`

Expand the files inside...

```bash
gunzip Image.gz
gunzip initramfs.gz
tar xvf initramfs
```

Import the uncompressed `Image` (Linux Kernel) into Ghidra.

For "Language" select AARCH64:LE:v8A:default...
-   Processor: AARCH64 
-   Variant: v8A 
-   Size: 64 
-   Endian: little 
-   Compiler: default

![For "Language" select AARCH64:LE:v8A:default](https://lupyuen.github.io/images/arm-ghidra7.png)

Here's the Jumpdrive `Image` (Linux Kernel) in Ghidra...

![Ghidra with PinePhone Linux Image](https://lupyuen.github.io/images/arm-ghidra2.png)

According to the Linux Kernel Header...

-   ["Booting AArch64 Linux"](https://www.kernel.org/doc/html/latest/arm64/booting.html)

We see Linux Kernel Magic Number `ARM\x64` at offset 0x38.

Image Load Offset is 0, according to the header.

Kernel Start Address on PinePhone is 0x4008 0000.

So we shift `Image` in Ghidra to start at 0x4008 0000...

-   Click Window > Memory Map

-   Click "ram"

-   Click the 4-Arrows icon ("Move a block to another address")

-   Change "New Start Address" to 40080000

![Ghidra with PinePhone Linux Image](https://lupyuen.github.io/images/arm-ghidra3.png)

## Will NuttX Boot On PinePhone?

_So will NuttX boot on PinePhone?_

It's highly plausible! We discovered (with happiness) that NuttX already generates an Arm64 Linux Kernel Header.

So NuttX could be a drop-in replacement for the PinePhone Linux Kernel! We just need to...

-   Write PinePhone Jumpdrive to a microSD Card (with Etcher, in FAT format)

-   Overwrite `Image.gz` by the (gzipped) NuttX Binary Image `nuttx.bin.gz`

-   Insert the microSD Card into PinePhone

-   Power on PinePhone

And NuttX should (theoretically) boot on PinePhone!

As mentioned earlier, we should rebuild NuttX so that `__start` is changed to 0x4008 0000 (from 0x4028 0000), as defined in the NuttX Linker Script: [boards/arm64/qemu/qemu-a53/scripts/dramboot.ld](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/boards/arm64/qemu/qemu-a53/scripts/dramboot.ld#L30-L33)

```text
SECTIONS
{
SECTIONS
{
  . = 0x40080000;  /* PinePhone uboot load address (kernel_addr_r) */
  /* Previously: . = 0x40280000; */  /* uboot load address */
  _start = .;
```

Also the Image Load Offset in our NuttX Image Header should be changed to 0x0 (from 0x48 0000): [arch/arm64/src/common/arm64_head.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L107)

```text
    .quad   0x0000               /* PinePhone Image load offset from start of RAM */
    # Previously: .quad   0x480000              /* Image load offset from start of RAM */
```

Later we'll increase the RAM Size to 2 GB (from 128 MB): [boards/arm64/qemu/qemu-a53/configs/nsh_smp/defconfig](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/boards/arm64/qemu/qemu-a53/configs/nsh_smp/defconfig#L47-L48)

```text
/* TODO: Increase to 2 GB for PinePhone */
CONFIG_RAM_SIZE=134217728
CONFIG_RAM_START=0x40000000
```

But not right now, because it might clash with the Device Tree and RAM File System.

_But will we see anything when NuttX boots on PinePhone?_

Not yet. We'll need to implement the UART Driver for NuttX...

# UART Driver for NuttX

Read the article...

-   ["NuttX RTOS for PinePhone: UART Driver"](https://lupyuen.github.io/articles/serial)

We won't see any output from NuttX until we implement the UART Driver for NuttX.

These are the Source Files for the QEMU UART Driver (PL011)...

-   [arch/arm64/src/qemu/qemu_serial.c](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/qemu/qemu_serial.c)

-   [arch/arm64/src/qemu/qemu_lowputc.S](https://github.com/apache/incubator-nuttx/blob/master/arch/arm64/src/qemu/qemu_lowputc.S)

[(More about PL011 UART)](https://krinkinmu.github.io/2020/11/29/PL011.html)

We'll replace the code above with the UART Driver for Allwinner A64 SoC...

-   [UART0 Memory Map](https://linux-sunxi.org/A64/Memory_map)

-   [Allwinner A64 UART](https://linux-sunxi.org/UART)

-   [Allwinner A64 User Manual](https://linux-sunxi.org/File:Allwinner_A64_User_Manual_V1.1.pdf)

-   [Allwinner A64 Info](https://linux-sunxi.org/A64)

To access the UART Port on PinePhone, we'll use this USB Serial Debug Cable...

-   [PinePhone Serial Debug Cable](https://wiki.pine64.org/index.php/PinePhone#Serial_console)

Which connects to the Headphone Port. Genius!

[(Remember to flip the Headphone Switch to OFF)](https://wiki.pine64.org/index.php/PinePhone#Privacy_switch_configuration)

![PinePhone UART Port in disguise](https://lupyuen.github.io/images/arm-uart.jpg)

[_PinePhone UART Port in disguise_](https://wiki.pine64.org/index.php/PinePhone#Serial_console)

## Garbled Console Output

The log appears garbled when `printf` is called by our NuttX Test Apps, due to concurrent printing by multiple tasks...

```text
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400e9000 _einit: 0x400e9000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddleLoNouptt
Shell (NSH) NuttX-11.0.0-RC2
```

[(Source)](https://gist.github.com/lupyuen/e49a22a9e39b7c024b984bea40377712)

It's supposed to show...

```text
nsh: sysinit: fopen failed: 2
nsh: mkfatfs: command not found
NuttShell (NSH) NuttX-11.0.0-RC2
nsh> nx_start: CPU0: Beginning Idle Loop
```

[(Source)](https://gist.github.com/lupyuen/7537da777d728a22ab379b1ef234a2d1)

_Why is the output garbled?_

The output is garbled because there 2 ways of writing to the Console Output...

- `up_putc`: Called by the NuttX Kernel to log messages (like `_info`)

- `a64_uart_send`: Allwinner A64 UART Driver is called by NuttX Apps to print messages (like `printf`)

To fix the output garbled at startup: Disable "Scheduler Informational Output" in...

"Build Setup > Debug Options > Enable Debug Features > Scheduler Debug Features"

This prevents `sinfo` from garbling the `printf` output...

- `sinfo` writes directly to UART Port character by character...

```text
  nx_start: CPU0: Beginning Idle Loop
  ```

- Whereas `printf` is buffered and writes the buffer to the UART Driver...

```text
  nsh: mkfatfs: command not found
  NuttShell (NSH) NuttX-11.0.0-RC2
  ```

Also we have a temporary workaround until this gets fixed: [a64_serial.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/91516c7cef28a79516d6196f070320a16649cf90/arch/arm64/src/a64/a64_serial.c#L424-L452)

```c
static void a64_uart_send(struct uart_dev_s *dev, int ch)
{
  const struct a64_uart_port_s *port = (struct a64_uart_port_s *)dev->priv;
  const struct a64_uart_config *config = &port->config;

#define BUFFER_UART
#ifdef BUFFER_UART
  //// TODO: Fix the garbled output. Buffer the chars until we see CR or LF.
  static char buf[256];
  static int pos = 0;
  if (ch != '>' && ch != '\r' && ch != '\n' && pos < sizeof(buf))
    {
      buf[pos] = ch;
      pos += 1;
      return;
    }
  for (int i = 0; i < pos; i++)
    {
      up_putc(buf[i]);      
    }
  pos = 0;
  up_putc(ch);
  UNUSED(config);
#else
  /* Write char to Transmit Holding Register (UART_THR) */

putreg8(ch, UART_THR(config->uart));
#endif // BUFFER_UART
}
```

This forces `a64_uart_send` to call `up_putc` to print an entire line of text. (Instead of character by character)

This also means that the `nsh` prompt will no longer echo text character by character. We need to press Enter to see the `nsh` output.

FYI: `printf` Console Output Stream is locked and unlocked with a Mutex. Let's log the locking and unlocking of the Mutex...

[nuttx/libs/libc/stdio/lib_libfilelock.c](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libfilelock.c#L39-L64)

```c
void flockfile(FAR struct file_struct *stream)
{
  up_putc('{'); // Log the Mutex Locking
  nxrmutex_lock(&stream->fs_lock);
}
...
void funlockfile(FAR struct file_struct *stream)
{
  up_putc('}'); // Log the Mutex Unlocking
  nxrmutex_unlock(&stream->fs_lock);
}
```

Output log shows that `{` and `}` (Mutex Locking and Unlocking) are nested...

```text
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400e9000 _einit: 0x400e9000
{{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{n}s}h{:} {s}y{s}i{n}i{t}:{ }f{o}p{e}n{ }f{a}i{l}e{d}:{ }2{
}
{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{}{{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{{}}{n}s}h{:} {m{k}f}a{t}f{s{:} }c{o{m}m}a{n{d} }n{o{t} }f{o{u}n}d{
```

How can be it locked twice without unlocking?

[`nxrmutex_lock`](https://github.com/apache/nuttx/blob/master/include/nuttx/mutex.h#L335-L377) calls...
- [`nxmutex_lock`](https://github.com/apache/nuttx/blob/master/include/nuttx/mutex.h#L135-L179), which calls...
- [`nxsem_wait`](https://github.com/apache/nuttx/blob/master/sched/semaphore/sem_wait.c#L42-L210), which calls...
- [`up_switch_context`](https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_switchcontext.c#L41-L103)

Let's print the Thread ID and Mutex Count...

```text
void flockfile(FAR struct file_struct *stream)
{
  nxrmutex_lock(&stream->fs_lock);
  _info("%p, thread=%d, mutex.count=%d\n", stream, gettid(), stream->fs_lock.count); // Log the Thread ID and Mutex Count
}

void funlockfile(FAR struct file_struct *stream)
{
  _info("%p, thread=%d, mutex.count=%d\n", stream, gettid(), stream->fs_lock.count); // Log the Thread ID and Mutex Count
  nxrmutex_unlock(&stream->fs_lock);
}
```

Thread ID is always the same. Mutex Count goes from 1 to 3 and drops to 2...

```text
lib_cxx_initialize: _sinit: 0x400e9000 _einit: 0x400e9000
flockfile: 0x40a5cc78, thread=2, mutex.count=1
flockfile: 0x40a5cc78, thread=2, mutex.count=2
flockfile: 0x40a5cc78, thread=2, mutex.count=3
funlockfile: 0x40a5cc78, thread=2, mutex.count=3
funlockfile: 0x40a5cc78, thread=2, mutex.count=2
```

Why? That's because [`nxrmutex_lock`](https://github.com/apache/nuttx/blob/master/include/nuttx/mutex.h#L335-L377) allows the Mutex to be locked multiple times __within the same thread.__

FYI: Here's how we verify whether our code is called by multiple CPU Cores...

```c
#include "../arch/arm64/src/common/arm64_arch.h"
_info("up_cpu_index=%d\n", MPIDR_TO_CORE(GET_MPIDR()));
// Shows: `up_cpu_index=0`

_info("mpidr_el1=%p\n", read_sysreg(mpidr_el1));
// Shows `mpidr_el1=0x80000000`
```

FYI: How `printf` works...

[`printf`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_printf.c#L32-L51) calls...
- [`vfprintf`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_vfprintf.c#L34-L56), which calls...
- [`libvsprintf`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libvsprintf.c#L1336-L1381), which calls...
- [`vsprintf_internal`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libvsprintf.c#L171-L1332), which calls...
- [`stream_putc`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libvsprintf.c#L70), which calls...
- ???, which calls...
- [`fputc`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_fputc.c#L31-L61), which calls...
- [`libfwrite`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libfwrite.c#L41-L180)

[`fputc`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_fputc.c#L31-L61) also calls...
- [`lib_libfflush`](https://github.com/apache/nuttx/blob/master/libs/libc/stdio/lib_libfflush.c#L40-L171)

## Configure UART Port

To support multiple UART Ports, we copied the following functions from the [Allwinner A1X UART Driver](https://github.com/apache/nuttx/blob/master/arch/arm/src/a1x/a1x_serial.c#L695-L987)...

- [`arm64_earlyserialinit`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L1323-L1398)

(Init the UART Ports)

- [`a64_uart_init`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L944-L996)

(Init the UART Pins. Called by [`arm64_earlyserialinit`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L1323-L1398))

- [`a64_uart_setup`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L453-L582)

(Configure the UART Port. Called when the UART Port is opened)

- [`a64_uart_irq_handler`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L301-L415)

(UART Interrupt Handler)

- [`a64_uart_receive`](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L727-L753)

(Receive UART Data)

[(Here's the log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/e5aa2baba64c8d904d6c16b7c5dbc68cd5c8f1e1/examples/hello/hello_main.c#L72-L270)

Inside the UART Driver, be careful when logging to the UART Port!

If the UART Port is busy doing logging, it won't allow us to the Baud Rate...

> "This register may only be accessed when the DLAB bit (UART_LCR[7]) is set and the UART is not busy (UART_USR[0] is zero)"

[(Allwinner A64 User Manual, Page 564)](https://lupyuen.github.io/images/Allwinner_A64_User_Manual_V1.1.pdf)

That's why we always wait for UART Not Busy before setting the Baud Rate. [(Like this)](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L417-L451)

_What happens if UART Is Busy when we set the Baud Rate?_

```text
up_setup: Enter DLAB=1
up_serialout: addr=0x1c2800c, before=0x3, after=0x83
up_setup: Set the BAUD divisor
up_serialout: addr=0x1c28004, before=0x0, after=0x0
up_serialout: addr=0x1c28000, before=0x0, after=0xd
up_setup: Clear DLAB
up_serialout: addr=0x1c2800c, before=0x3, after=0x3
```

[(Source)](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/83566af2e58f92ae42fd434ce97f919404245986/arch/arm64/src/a64/a64_serial.c#L1306-L1313)

From above, we see that the Baud Rate is not read correctly...

```text
up_serialout: addr=0x1c28000, before=0x0, after=0xd
// For UART0: Before should be 0xd
```

And DLAB doesn't get cleared correctly...

```text
up_setup: Enter DLAB=1
up_serialout: addr=0x1c2800c, before=0x3, after=0x83
...
up_setup: Clear DLAB
up_serialout: addr=0x1c2800c, before=0x3, after=0x3
// Before should be 0x83, not 0x3
```

We fix this by disabling the logging and waiting for UART Not Busy before setting the Baud Rate. [(Like this)](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/uart3/arch/arm64/src/a64/a64_serial.c#L530-L549)

The changes have been upstreamed to NuttX Mainline...

-   [__Pull Request: Support multiple UART Ports__](https://github.com/apache/nuttx/pull/9243)

_How do we enable a UART Port? Like UART3?_

Head over to the NuttX Build Configuration...

```bash
make menuconfig
```

Then select...

- System Type > Allwinner A64 Peripheral Selection > UART3

To configure the Baud Rate, Parity and Stop Bits...

- Device Drivers > Serial Driver Support > UART3 Configuration

(The default Baud Rate / Bits / Parity / Stop Bits work OK with the PinePhone LTE Modem on UART3: 115.2 kbps / 8 Bits / No Parity / 1 Stop Bit)

Let's test the PinePhone LTE Modem on UART3...

## Test UART3 Port

In the previous section we have configured UART3 for PinePhone's [4G LTE Modem](https://lupyuen.github.io/articles/lte).

This is how we read and write the UART3 port via `/dev/ttyS1`: [hello_main.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/e5aa2baba64c8d904d6c16b7c5dbc68cd5c8f1e1/examples/hello/hello_main.c#L38-L70)

```c
// Open /dev/ttyS1 (UART3)
int fd = open("/dev/ttyS1", O_RDWR);
printf("Open /dev/ttyS1: fd=%d\n", fd);
assert(fd > 0);

// Repeat 5 times: Write command and read response
for (int i = 0; i < 5; i++) {
  // Write command
  const char cmd[] = "AT\r";
  ssize_t nbytes = write(fd, cmd, sizeof(cmd));
  printf("Write command: nbytes=%ld\n", nbytes);
  assert(nbytes == sizeof(cmd));

// Read response
  static char buf[1024];
  nbytes = read(fd, buf, sizeof(buf) - 1);
  if (nbytes >= 0) { buf[nbytes] = 0; }
  printf("Response: nbytes=%ld\n%s\n", nbytes, buf);

// Wait a while
  sleep(2);
}

// Close the device
close(fd);
```

LTE Modem works OK with UART3 on NuttX yay! See the test log here...

-   ["Test UART with NuttX"](https://lupyuen.github.io/articles/lte#test-uart-with-nuttx)

__Note:__ Modem UART flow control is broken

> "Not resolved in v1.2 -- assumption is that USB will be used for high-bandwidth modem I/O.

> BB-TX and BB-RX are connected to UART3 (PD0/PD1). BB-RTS and BB-CTS are connected to UART4 (PD4/PD5). To use hardware flow control, TX/RX would need to be connected to UART4, swapping PD0/PD1 with the motor control and rear camera reset GPIOs at PD2/PD3. This would need a device tree change.

> Hardware flow control can be disabled with the AT+IFC command, and USB can also be used for commands instead of the UART. So the impact of this problem is unclear."

[(Source)](https://wiki.pine64.org/wiki/PinePhone_v1.1_-_Braveheart#Modem_UART_flow_control_is_broken)

# Boot NuttX on PinePhone

Read the article...

-   ["PinePhone boots Apache NuttX RTOS"](https://lupyuen.github.io/articles/uboot)

## PinePhone U-Boot Log

Before starting the Linux Kernel, PinePhone boots by running the U-Boot Bootloader...

-   [A64 Boot ROM](https://linux-sunxi.org/BROM#A64)

-   [A64 U-Boot](https://linux-sunxi.org/U-Boot)

-   [A64 U-Boot SPL](https://linux-sunxi.org/BROM#U-Boot_SPL_limitations)

-   [SD Card Layout](https://linux-sunxi.org/Bootable_SD_card#SD_Card_Layout)

Here's the PinePhone U-Boot Log captured with the USB Serial Debug Cable...

(Press Enter repeatedly when PinePhone powers on to enter the U-Boot Prompt)

```text
$ screen /dev/ttyUSB0 115200

DRAM: 2048 MiB
Trying to boot from MMC1
NOTICE:  BL31: v2.2(release):v2.2-904-gf9ea3a629
NOTICE:  BL31: Built : 15:32:12, Apr  9 2020
NOTICE:  BL31: Detected Allwinner A64/H64/R18 SoC (1689)
NOTICE:  BL31: Found U-Boot DTB at 0x4064410, model: PinePhone
NOTICE:  PSCI: System suspend is unavailable

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

DRAM:  2 GiB
MMC:   Device 'mmc@1c11000': seq 1 is in use by 'mmc@1c10000'
mmc@1c0f000: 0, mmc@1c10000: 2, mmc@1c11000: 1
Loading Environment from FAT... *** Warning - bad CRC, using default environment

starting USB...
No working controllers found
Hit any key to stop autoboot:

=> help
?         - alias for 'help'
base      - print or set address offset
bdinfo    - print Board Info structure
blkcache  - block cache diagnostics and control
boot      - boot default, i.e., run 'bootcmd'
bootd     - boot default, i.e., run 'bootcmd'
bootelf   - Boot from an ELF image in memory
booti     - boot Linux kernel 'Image' format from memory
bootm     - boot application image from memory
bootvx    - Boot vxWorks from an ELF image
cmp       - memory compare
coninfo   - print console devices and information
cp        - memory copy
crc32     - checksum calculation
dm        - Driver model low level access
echo      - echo args to console
editenv   - edit environment variable
env       - environment handling commands
exit      - exit script
ext2load  - load binary file from a Ext2 filesystem
ext2ls    - list files in a directory (default /)
ext4load  - load binary file from a Ext4 filesystem
ext4ls    - list files in a directory (default /)
ext4size  - determine a file's size
false     - do nothing, unsuccessfully
fatinfo   - print information about filesystem
fatload   - load binary file from a dos filesystem
fatls     - list files in a directory (default /)
fatmkdir  - create a directory
fatrm     - delete a file
fatsize   - determine a file's size
fatwrite  - write file into a dos filesystem
fdt       - flattened device tree utility commands
fstype    - Look up a filesystem type
go        - start application at address 'addr'
gpio      - query and control gpio pins
gpt       - GUID Partition Table
gzwrite   - unzip and write memory to block device
help      - print command description/usage
iminfo    - print header information for application image
imxtract  - extract a part of a multi-image
itest     - return true/false on integer compare
ln        - Create a symbolic link
load      - load binary file from a filesystem
loadb     - load binary file over serial line (kermit mode)
loads     - load S-Record file over serial line
loadx     - load binary file over serial line (xmodem mode)
loady     - load binary file over serial line (ymodem mode)
loop      - infinite loop on address range
ls        - list files in a directory (default /)
lzmadec   - lzma uncompress a memory region
md        - memory display
mm        - memory modify (auto-incrementing address)
mmc       - MMC sub system
mmcinfo   - display MMC info
mw        - memory write (fill)
nm        - memory modify (constant address)
part      - disk partition related commands
poweroff  - Perform POWEROFF of the device
printenv  - print environment variables
random    - fill memory with random pattern
reset     - Perform RESET of the CPU
run       - run commands in an environment variable
save      - save file to a filesystem
saveenv   - save environment variables to persistent storage
setenv    - set environment variables
setexpr   - set environment variable as the result of eval expression
sf        - SPI flash sub-system
showvar   - print local hushshell variables
size      - determine a file's size
sleep     - delay execution for some time
source    - run script from memory
sysboot   - command to get and boot from syslinux files
test      - minimal test like /bin/sh
true      - do nothing, successfully
unlz4     - lz4 uncompress a memory region
unzip     - unzip a memory region
usb       - USB sub-system
usbboot   - boot from USB device
version   - print monitor, compiler and linker version

=> printenv
arch=arm
baudrate=115200
board=sunxi
board_name=sunxi
boot_a_script=load ${devtype} ${devnum}:${distro_bootpart} ${scriptaddr} ${prefix}${script}; source ${scriptaddr}
boot_extlinux=sysboot ${devtype} ${devnum}:${distro_bootpart} any ${scriptaddr} ${prefix}${boot_syslinux_conf}
boot_net_usb_start=usb start
boot_prefixes=/ /boot/
boot_script_dhcp=boot.scr.uimg
boot_scripts=boot.scr.uimg boot.scr
boot_syslinux_conf=extlinux/extlinux.conf
boot_targets=fel mmc_auto usb0 
bootcmd=run distro_bootcmd
bootcmd_fel=if test -n ${fel_booted} && test -n ${fel_scriptaddr}; then echo '(FEL boot)'; source ${fel_scriptaddr}; fi
bootcmd_mmc0=devnum=0; run mmc_boot
bootcmd_mmc1=devnum=1; run mmc_boot
bootcmd_mmc_auto=if test ${mmc_bootdev} -eq 1; then run bootcmd_mmc1; run bootcmd_mmc0; elif test ${mmc_bootdev} -eq 0; then run bootcmd_mmc0; run bootcmd_mmc1; fi
bootcmd_usb0=devnum=0; run usb_boot
bootdelay=0
bootm_size=0xa000000
console=ttyS0,115200
cpu=armv8
dfu_alt_info_ram=kernel ram 0x40080000 0x1000000;fdt ram 0x4FA00000 0x100000;ramdisk ram 0x4FE00000 0x4000000
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done
ethaddr=02:ba:8c:73:bf:ca
fdt_addr_r=0x4FA00000
fdtcontroladdr=bbf4dd40
fdtfile=allwinner/sun50i-a64-pinephone.dtb
kernel_addr_r=0x40080000
mmc_boot=if mmc dev ${devnum}; then devtype=mmc; run scan_dev_for_boot_part; fi
mmc_bootdev=0
partitions=name=loader1,start=8k,size=32k,uuid=${uuid_gpt_loader1};name=loader2,size=984k,uuid=${uuid_gpt_loader2};name=esp,size=128M,bootable,uuid=${uuid_gpt_esp};name=system,size=-,uuid=${uuid_gpt_system};
preboot=usb start
pxefile_addr_r=0x4FD00000
ramdisk_addr_r=0x4FE00000
scan_dev_for_boot=echo Scanning ${devtype} ${devnum}:${distro_bootpart}...; for prefix in ${boot_prefixes}; do run scan_dev_for_extlinux; run scan_dev_for_scripts; done;
scan_dev_for_boot_part=part list ${devtype} ${devnum} -bootable devplist; env exists devplist || setenv devplist 1; for distro_bootpart in ${devplist}; do if fstype ${devtype} ${devnum}:${distro_bootpart} bootfstype; then run scan_dev_for_boot; fi; done; setenv devplist
scan_dev_for_extlinux=if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${boot_syslinux_conf}; then echo Found ${prefix}${boot_syslinux_conf}; run boot_extlinux; echo SCRIPT FAILED: continuing...; fi
scan_dev_for_scripts=for script in ${boot_scripts}; do if test -e ${devtype} ${devnum}:${distro_bootpart} ${prefix}${script}; then echo Found U-Boot script ${prefix}${script}; run boot_a_script; echo SCRIPT FAILED: continuing...; fi; done
scriptaddr=0x4FC00000
serial#=92c07dba8c73bfca
soc=sunxi
stderr=serial@1c28000
stdin=serial@1c28000
stdout=serial@1c28000
usb_boot=usb start; if usb dev ${devnum}; then devtype=usb; run scan_dev_for_boot_part; fi
uuid_gpt_esp=c12a7328-f81f-11d2-ba4b-00a0c93ec93b
uuid_gpt_system=b921b045-1df0-41c3-af44-4c6f280d3fae

Environment size: 2861/131068 bytes

=> boot
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
4275261 bytes read in 192 ms (21.2 MiB/s)
Uncompressed size: 10170376 = 0x9B3008
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 51 ms (20.2 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

/ # 
```

According to the U-Boot Log, the Start of RAM `kernel_addr_r` is 0x4008 0000.

We need to set this in the NuttX Linker Script and the NuttX Header...

## NuttX Boots On PinePhone

In the previous section, U-Boot says that the Start of RAM `kernel_addr_r` is 0x4008 0000.

Let's set this in the NuttX Linker Script and the NuttX Header...

-   Change Image Load Offset in NuttX Header to 0x0 (from 0x48000)

[(See the changes)](https://github.com/lupyuen/incubator-nuttx/commit/9916b52f9dba17944a35aafd4c21fb9eabb17c0e#diff-a830678a9f1b0773c404196c86ad45d1ef7d7e51a52b935cd08df35f5949aaf8)

-   Change NuttX Linker Script to set the Start Address `_start` to 0x4008 0000 (from 0x4028 0000)

[(See the changes)](https://github.com/lupyuen/incubator-nuttx/commit/9916b52f9dba17944a35aafd4c21fb9eabb17c0e#diff-d8d987cb5ba644b5f79987e42663217799e03e384552b2e8dbb041f145fa8ad1)

For PinePhone Allwinner A64 UART: We reused the previous code for transmitting output to UART...

```text
/* PL011 UART transmit character
 * xb: register which contains the UART base address
 * wt: register which contains the character to transmit
 */

.macro early_uart_transmit xb, wt
    strb  \wt, [\xb]             /* -> UARTDR (Data Register) */
.endm
```

[(Source)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_lowputc.S#L87-L94)

But we updated the UART Register Address for Allwinner A64 UART...

```text
 /* 32-bit register definition for qemu pl011 uart */

/* PinePhone Allwinner A64 UART0 Base Address: */
 #define UART1_BASE_ADDRESS 0x01C28000
 /* Previously: #define UART1_BASE_ADDRESS 0x9000000 */
 #define EARLY_UART_PL011_BAUD_RATE  115200
```

[(Source)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_lowputc.S#L40-L45)

Right now we don't check if UART is ready to transmit, so our UART output will have missing characters. This needs to be fixed...

```text
/* PL011 UART wait UART to be ready to transmit
 * xb: register which contains the UART base address
 * c: scratch register number
 */

.macro early_uart_ready xb, wt
1:
    # TODO: Wait for PinePhone Allwinner A64 UART
    # ldrh  \wt, [\xb, #0x18]      /* <- UARTFR (Flag register) */
    # tst   \wt, #0x8              /* Check BUSY bit */
    # b.ne  1b                     /* Wait for the UART to be ready */
.endm
```

[(Source)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_lowputc.S#L74-L85)

We don't init the UART Port because U-Boot has kindly done it for us. This needs to be fixed...

```text
/* PL011 UART initialization
 * xb: register which contains the UART base address
 * c: scratch register number
 */

GTEXT(up_earlyserialinit)
SECTION_FUNC(text, up_earlyserialinit)
    # TODO: Set PinePhone Allwinner A64 Baud Rate Divisor: UART_LCR (DLAB), UART_DLL, UART_DLH
    # ldr   x15, =UART1_BASE_ADDRESS
    # mov   x0, #(7372800 / EARLY_UART_PL011_BAUD_RATE % 16)
    # strh  w0, [x15, #0x28]      /* -> UARTFBRD (Baud divisor fraction) */
    # mov   x0, #(7372800 / EARLY_UART_PL011_BAUD_RATE / 16)
    # strh  w0, [x15, #0x24]      /* -> UARTIBRD (Baud divisor integer) */
    # mov   x0, #0x60             /* 8n1 */
    # str   w0, [x15, #0x2C]      /* -> UARTLCR_H (Line control) */
    # ldr   x0, =0x00000301       /* RXE | TXE | UARTEN */
    # str   w0, [x15, #0x30]      /* -> UARTCR (Control Register) */
    ret
```

[(Source)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_lowputc.S#L55-L72)

With the above changes, NuttX boots on PinePhone yay!

![NuttX Boots On PinePhone](https://lupyuen.github.io/images/Screenshot_2022-08-26_08-04-34_080626.png)

[__Watch the Demo on YouTube__](https://youtube.com/shorts/WmRzfCiWV6o?feature=share)

## NuttX Boot Log

This is how we build NuttX for PinePhone...

```bash
## TODO: Install Build Prerequisites
## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Create NuttX Directory
mkdir nuttx
cd nuttx

## Download NuttX OS for PinePhone
git clone \
    --recursive \
    --branch pinephone \
    https://github.com/lupyuen/incubator-nuttx \
    nuttx

## Download NuttX Apps for PinePhone
git clone \
    --recursive \
    --branch pinephone \
    https://github.com/lupyuen/incubator-nuttx-apps \
    apps

## We'll build NuttX inside nuttx/nuttx
cd nuttx

## Configure NuttX for Single Core
./tools/configure.sh -l qemu-a53:nsh

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1

## Compress the NuttX Binary Image
cp nuttx.bin Image
rm -f Image.gz
gzip Image

## Copy compressed NuttX Binary Image to Jumpdrive microSD.
## How to create Jumpdrive microSD: https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive
## TODO: Change the microSD Path
cp Image.gz "/Volumes/NO NAME"
```

Insert the Jumpdrive microSD into PinePhone and power up.

Here's the UART Log of NuttX booting on PinePhone...

```text
DRAM: 2048 MiB
Trying to boot from MMC1
NOTICE:  BL31: v2.2(release):v2.2-904-gf9ea3a629
NOTICE:  BL31: Built : 15:32:12, Apr  9 2020
NOTICE:  BL31: Detected Allwinner A64/H64/R18 SoC (1689)
NOTICE:  BL31: Found U-Boot DTB at 0x4064410, model: PinePhone
NOTICE:  PSCI: System suspend is unavailable

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
99784 bytes read in 8 ms (11.9 MiB/s)
Uncompressed size: 278528 = 0x44000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 51 ms (20.2 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x400c4000, heap_size=0x7f3c000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400a7000
up_timer_initialize: Before writing: vbar_el1=0x40227000
up_timer_initialize: After writing: vbar_el1=0x400a7000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400a7000 _einit: 0x400a7000 _stext: 0x40080000 _etext: 0x400a8000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddle  L oNouptt
 Shell (NSH) NuttX-10.3.0-RC2

nsh> uname -a
NuttX 10.3.0-RC2 fc909c6-dirty Sep  1 2022 17:05:44 arm64 qemu-a53

nsh> help
help usage:  help [-v] [<cmd>]

Builtin Apps:
  getprime  hello     nsh       ostest    sh

nsh> hello
task_spawn: name=hello entry=0x4009b1a0 file_actions=0x400c9580 attr=0x400c9588 argv=0x400c96d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
Hello, World!!

nsh> ls /dev
/dev:
 console
 null
 ram0
 ram2
 ttyS0
 zero
```

[__Watch the Demo on YouTube__](https://youtube.com/shorts/WmRzfCiWV6o?feature=share)

The output is slightly garbled, the UART Driver needs fixing.

# Interrupt Controller

Read the article...

-   ["NuttX RTOS for PinePhone: Fixing the Interrupts"](https://lupyuen.github.io/articles/interrupt)

Let's talk about the __Arm Generic Interrupt Controller (GIC)__ for PinePhone...

```text
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
```

This is the current implementation of [Arm GIC Version 3](https://developer.arm.com/documentation/ihi0069/latest) in NuttX Arm64...

-   [arch/arm64/src/common/arm64_gicv3.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c)

-   [arch/arm64/src/common/arm64_gic.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gic.h)

This implementation won't work on PinePhone, so we have commented out the existing code and inserted our own implementation.

_Why won't Arm GIC Version 3 work on PinePhone?_

According to the Allwinner A64 SoC User Manual (page 210, "GIC"), PinePhone's Interrupt Controller runs on...

-   [Arm GIC PL400](https://developer.arm.com/documentation/ddi0471/b/introduction/about-the-gic-400), which is based on...

-   [Arm GIC Version 2](https://developer.arm.com/documentation/ihi0048/latest/)

We'll have to downgrade [arm64_gicv3.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c) to support Arm GIC Version 2 for PinePhone.

_Does NuttX implement Arm GIC Version 2?_

NuttX has an implementation of Arm GIC Version 2, but it's based on Arm32. We'll port it from Arm32 to Arm64...

-   [arch/arm/src/armv7-a/arm_gicv2.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/armv7-a/arm_gicv2.c)

-   [arch/arm/src/armv7-a/arm_gicv2_dump.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/armv7-a/arm_gicv2_dump.c)

-   [arch/arm/src/armv7-a/gic.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/armv7-a/gic.h)

-   [arch/arm/src/armv7-a/mpcore.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/armv7-a/mpcore.h)

-   [arch/arm/src/imx6/chip.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/imx6/chip.h)

-   [arch/arm/src/imx6/hardware/imx_memorymap.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm/src/imx6/hardware/imx_memorymap.h)

By reusing the code above, we have implemented Arm GIC Version 2 for PinePhone...

-   [arch/arm64/src/common/arm64_gicv3.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L765-L823)

We made minor tweaks to NuttX's implementation of GIC Version 2...

-   [Changes for arch/arm/src/armv7-a/arm_gicv2.c](https://github.com/lupyuen/incubator-nuttx/commit/6fa0e7e5d2beddad07890c83d2ee428a3f2b8a62#diff-6e1132aef124dabaf94c200ab06d65c7bc2b9967bf76a46aba71a7f43b5fb219)

-   [Changes for arch/arm/src/armv7-a/arm_gicv2_dump.c](https://github.com/lupyuen/incubator-nuttx/commit/4fc2669fef62d12ba1dd428f2daf03d3bc362501#diff-eb05c977988d59202a9472f6fa7f9dc290724662ad6d15a4ba99b8f1fc1dc8f8)

-   [Changes for arch/arm/src/armv7-a/gic.h](https://github.com/lupyuen/incubator-nuttx/commit/6fa0e7e5d2beddad07890c83d2ee428a3f2b8a62#diff-b4fcb67b71de954c942ead9bb0868e720a5802c90743f0a1883f84b7565e1a0f)

_Where in memory is the GIC located?_

According to the Allwinner A64 SoC User Manual (page 74, "Memory Mapping"), the GIC is located at this address...

(Why "CPUS can’t access"?)

The __Interrupt Sources__ are defined in the Allwinner A64 SoC User Manual (page 210, "GIC")...

-   16 x Software-Generated Interrupts (SGI)

"This is an interrupt generated by software writing to a GICD_SGIR register in the GIC. The system uses SGIs for interprocessor communication."

-   16 x Private Peripheral Interrupts (PPI)

"This is a peripheral interrupt that is specific to a single processor"

-   125 x Shared Peripheral Interrupts (SPI)

"This is a peripheral interrupt that the Distributor can route to any of a specified combination of processors"

To verify the GIC Version, read the __Peripheral ID2 Register (ICPIDR2)__ at Offset 0xFE8 of GIC Distributor.

Bits 4 to 7 of ICPIDR2 are...

-   0x1 for GIC Version 1
-   0x2 for GIC Version 2

This is how we implement the GIC Version verification: [arch/arm64/src/common/arm64_gicv3.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L710-L734)

```c
// Init GIC v2 for PinePhone. See https://github.com/lupyuen/pinephone-nuttx#interrupt-controller
int arm64_gic_initialize(void)
{
  sinfo("TODO: Init GIC for PinePhone\n");

// To verify the GIC Version, read the Peripheral ID2 Register (ICPIDR2) at Offset 0xFE8 of GIC Distributor.
  // Bits 4 to 7 of ICPIDR2 are...
  // - 0x1 for GIC Version 1
  // - 0x2 for GIC Version 2
  // GIC Distributor is at 0x01C80000 + 0x1000.
  // See https://github.com/lupyuen/pinephone-nuttx#interrupt-controller
  const uint8_t *ICPIDR2 = (const uint8_t *) (CONFIG_GICD_BASE + 0xFE8);
  uint8_t version = (*ICPIDR2 >> 4) & 0b1111;
  sinfo("GIC Version is %d\n", version);
  DEBUGASSERT(version == 2);

// arm_gic0_initialize must be called on CPU0
  arm_gic0_initialize();

// arm_gic_initialize must be called for all CPUs
  // TODO: Move to arm64_gic_secondary_init
  arm_gic_initialize();

return 0;
}
```

See below for the [GIC Register Dump](https://github.com/lupyuen/pinephone-nuttx#gic-register-dump).

## Multi Core SMP

Right now NuttX is configured to run on a Single Core for PinePhone.

To support all 4 Cores on PinePhone with SMP (Symmetric Multi-Processing), we need to fix these in the Generic Interrupt Controller Version 2...

https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L717-L743

```c
// Init GIC v2 for PinePhone. See https://github.com/lupyuen/pinephone-nuttx#interrupt-controller
int arm64_gic_initialize(void)
{
  ...
  // arm_gic0_initialize must be called on CPU0
  arm_gic0_initialize();

// arm_gic_initialize must be called for all CPUs
  // TODO: Move to arm64_gic_secondary_init
  arm_gic_initialize();
```

https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L746-L761

```c
#ifdef CONFIG_SMP
...
// TODO: Init GIC for PinePhone
void arm64_gic_secondary_init(void)
{
  sinfo("TODO: Init GIC Secondary for PinePhone\n");

//  TODO: arm_gic_initialize must be called for all CPUs.
  arm_gic_initialize();
}
#endif  //  NOTUSED
```

And we rebuild NuttX for Multi Core...

```bash
## Erase the NuttX Configuration
make distclean

## Configure NuttX for 4 Cores
./tools/configure.sh -l qemu-a53:nsh_smp

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

## System Timer

NuttX starts the System Timer when it boots. Here's how the System Timer is started: [arch/arm64/src/common/arm64_arch_timer.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L212-L233)

```c
void up_timer_initialize(void)
{
  uint64_t curr_cycle;

arch_timer_rate   = arm64_arch_timer_get_cntfrq();
  cycle_per_tick    = ((uint64_t)arch_timer_rate / (uint64_t)TICK_PER_SEC);

sinfo("%s: cp15 timer(s) running at %lu.%02luMHz, cycle %ld\n", __func__,
        (unsigned long)arch_timer_rate / 1000000,
        (unsigned long)(arch_timer_rate / 10000) % 100, cycle_per_tick);

irq_attach(ARM_ARCH_TIMER_IRQ, arm64_arch_timer_compare_isr, 0);
  arm64_gic_irq_set_priority(ARM_ARCH_TIMER_IRQ, ARM_ARCH_TIMER_PRIO,
                             ARM_ARCH_TIMER_FLAGS);

curr_cycle = arm64_arch_timer_count();
  arm64_arch_timer_set_compare(curr_cycle + cycle_per_tick);
  arm64_arch_timer_enable(true);

up_enable_irq(ARM_ARCH_TIMER_IRQ);
  arm64_arch_timer_set_irq_mask(false);
}
```

At every tick, the System Timer triggers an interrupt that calls [`arm64_arch_timer_compare_isr`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L109-L169)

(`CONFIG_SCHED_TICKLESS` is undefined)

__Timer IRQ `ARM_ARCH_TIMER_IRQ`__ is defined in [arch/arm64/src/common/arm64_arch_timer.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.h#L38-L45)

```c
#define CONFIG_ARM_TIMER_SECURE_IRQ         (GIC_PPI_INT_BASE + 13)
#define CONFIG_ARM_TIMER_NON_SECURE_IRQ     (GIC_PPI_INT_BASE + 14)
#define CONFIG_ARM_TIMER_VIRTUAL_IRQ        (GIC_PPI_INT_BASE + 11)
#define CONFIG_ARM_TIMER_HYP_IRQ            (GIC_PPI_INT_BASE + 10)

#define ARM_ARCH_TIMER_IRQ	CONFIG_ARM_TIMER_VIRTUAL_IRQ
#define ARM_ARCH_TIMER_PRIO	IRQ_DEFAULT_PRIORITY
#define ARM_ARCH_TIMER_FLAGS	IRQ_TYPE_LEVEL
```

`GIC_PPI_INT_BASE` is defined in [arch/arm64/src/common/arm64_gic.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gic.h#L120-L128)

```c
#define GIC_SGI_INT_BASE            0
#define GIC_PPI_INT_BASE            16
#define GIC_IS_SGI(intid)           (((intid) >= GIC_SGI_INT_BASE) && \
                                     ((intid) < GIC_PPI_INT_BASE))

#define GIC_SPI_INT_BASE            32
#define GIC_NUM_INTR_PER_REG        32
#define GIC_NUM_CFG_PER_REG         16
#define GIC_NUM_PRI_PER_REG         4
```

## Timer Interrupt Isn't Handled

Previously NuttX hangs midsentence while booting on PinePhone, let's find out how we fixed it...

```text
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
uart_regi
```

Based on our experiments, it seems the [System Timer](https://github.com/lupyuen/pinephone-nuttx#system-timer) triggered a Timer Interrupt, and NuttX hangs while attempting to handle the Timer Interrupt.

The Timer Interrupt Handler [`arm64_arch_timer_compare_isr`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L109-L169) is never called. (We checked using [`up_putc`](https://github.com/lupyuen/pinephone-nuttx#boot-debugging))

_Is it caused by PinePhone's GIC?_

This problem doesn't seem to be caused by [PinePhone's Generic Interrupt Controller (GIC)](https://github.com/lupyuen/pinephone-nuttx#interrupt-controller) that we have implemented. We [successfully tested PinePhone's GIC](https://github.com/lupyuen/pinephone-nuttx#test-pinephone-gic-with-qemu) with QEMU.

Let's troubleshoot the Timer Interrupt...

-   We called [`up_putc`](https://github.com/lupyuen/pinephone-nuttx#boot-debugging) to understand [how Interrupts are handled on NuttX](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts).

We also added Debug Code to the [Arm64 Interrupt Handler](https://github.com/lupyuen/pinephone-nuttx#interrupt-debugging).

[(Maybe we should have used GDB with QEMU)](https://github.com/apache/incubator-nuttx/tree/master/boards/arm64/qemu/qemu-a53)

-   We [dumped the Interrupt Vector Table](https://github.com/lupyuen/pinephone-nuttx#dump-interrupt-vector-table).

We verified that the Timer Interrupt Handler Address in the table is correct.

-   We confirmed that [Interrupt Dispatcher `irq_dispatch`](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts) isn't called.

And [Unexpected Interrupt Handler `irq_unexpected_isr`](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts) isn't called either.

-   Let's backtrack, maybe there's a problem in the Arm64 Interrupt Handler?

But [`arm64_enter_exception`](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts) and [`arm64_irq_handler`](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts) aren't called either.

-   Maybe the __Arm64 Vector Table `_vector_table`__ isn't correctly configured?

[arch/arm64/src/common/arm64_vector_table.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L93-L232)

And we're right! The Arm64 Vector Table is indeed incorrectly configured! Here why...

## Arm64 Vector Table Is Wrong

Earlier we saw that the Interrupt Handler wasn't called for System Timer Interrupt. And it might be due to problems in the __Arm64 Vector Table `_vector_table`__: [arch/arm64/src/common/arm64_vector_table.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L93-L232)

Let's check whether the Arm64 Vector Table `_vector_table` is correctly configured in the Arm CPU: [arch/arm64/src/common/arm64_arch_timer.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L212-L235)

```c
void up_timer_initialize(void)
{
  ...
  // Attach System Timer Interrupt Handler
  irq_attach(ARM_ARCH_TIMER_IRQ, arm64_arch_timer_compare_isr, 0);

// For PinePhone: Read Vector Base Address Register EL1
  extern void *_vector_table[];
  sinfo("_vector_table=%p\n", _vector_table);
  sinfo("Before writing: vbar_el1=%p\n", read_sysreg(vbar_el1));
```

After attaching the Interrupt Handler for System Timer, we read the Arm64 [Vector Base Address Register EL1](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts). Here's the output...

```text
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400a7000
up_timer_initialize: Before writing: vbar_el1=0x40227000
```

Aha! `_vector_table` is at 0x400a7000... But Vector Base Address Register EL1 says 0x40227000!

Our Arm64 CPU is pointing to the wrong Arm64 Vector Table... Hence our Interrupt Handler is never called!

Let's fix the Vector Base Address Register EL1: [arch/arm64/src/common/arm64_arch_timer.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L212-L235)

```c
  // For PinePhone: Write Vector Base Address Register EL1
  write_sysreg((uint64_t)_vector_table, vbar_el1);
  ARM64_ISB();

// For PinePhone: Read Vector Base Address Register EL1
  sinfo("After writing: vbar_el1=%p\n", read_sysreg(vbar_el1));
```

This writes the correct value of `_vector_table` back into Vector Base Address Register EL1. Here's the output...

Yep Vector Base Address Register EL1 is now correct.

And our Interrupt Handlers are now working fine yay!

## Test PinePhone GIC with QEMU

This is how we build NuttX for QEMU with [Generic Interrupt Controller (GIC) Version 2](https://github.com/lupyuen/pinephone-nuttx#interrupt-controller)...

```bash
## TODO: Install Build Prerequisites
## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Create NuttX Directory
mkdir nuttx
cd nuttx

## Download NuttX OS for QEMU with GIC Version 2
git clone \
    --recursive \
    --branch gicv2 \
    https://github.com/lupyuen/incubator-nuttx \
    nuttx

## Download NuttX Apps for QEMU
git clone \
    --recursive \
    --branch arm64 \
    https://github.com/lupyuen/incubator-nuttx-apps \
    apps

## We'll build NuttX inside nuttx/nuttx
cd nuttx

## Configure NuttX for Single Core
./tools/configure.sh -l qemu-a53:nsh

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

And this is how we tested PinePhone's GIC Version 2 with QEMU...

```bash
## Run GIC v2 with QEMU
qemu-system-aarch64 \
  -smp 4 \
  -cpu cortex-a53 \
  -nographic \
  -machine virt,virtualization=on,gic-version=2 \
  -net none \
  -chardev stdio,id=con,mux=on \
  -serial chardev:con \
  -mon chardev=con,mode=readline \
  -kernel ./nuttx
```

Note that `gic-version=2`, instead of the usual GIC Version 3 for NuttX Arm64.

Also we simulated 4 Cores of Arm Cortex-A53 (similar to PinePhone): `-smp 4`

QEMU boots OK with PinePhone's GIC Version 2...

NuttShell (NSH) NuttX-10.3.0-RC2
nsh> nx_start: CPU0: Beginning Idle Loop
```

So our implementation of GIC Version 2 for PinePhone is probably OK.

_Is the Timer Interrupt triggered correctly with PinePhone GIC?_

Yes, we verified that the Timer Interrupt Handler [`arm64_arch_timer_compare_isr`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L109-L169) is  called periodically. (We checked using [`up_putc`](https://github.com/lupyuen/pinephone-nuttx#boot-debugging))

_How did we get the GIC Base Addresses?_

```text
arm64_gic_initialize: CONFIG_GICD_BASE=0x8000000
arm64_gic_initialize: CONFIG_GICR_BASE=0x8010000
```

We got the GIC v2 Base Addresses for GIC Distributor (`CONFIG_GICD_BASE`) and GIC CPU Interface (`CONFIG_GICR_BASE`) by dumping the Device Tree from QEMU...

```bash
## GIC v2 Dump Device Tree
qemu-system-aarch64 \
  -smp 4 \
  -cpu cortex-a53 \
  -nographic \
  -machine virt,virtualization=on,gic-version=2,dumpdtb=gicv2.dtb \
  -net none \
  -chardev stdio,id=con,mux=on \
  -serial chardev:con \
  -mon chardev=con,mode=readline \
  -kernel ./nuttx

## Convert Device Tree to text format
dtc -o gicv2.dts -O dts -I dtb gicv2.dtb
```

The Base Addresses are revealed in the GIC v2 Device Tree: [gicv2.dts](https://github.com/lupyuen/incubator-nuttx/blob/gicv2/gicv2.dts#L324)...

```text
intc@8000000 {
reg = <
    0x00 0x8000000 0x00 0x10000  //  GIC Distributor:   0x8000000
    0x00 0x8010000 0x00 0x10000  //  GIC CPU Interface: 0x8010000
    0x00 0x8030000 0x00 0x10000  //  VGIC Virtual Interface Control: 0x8030000
    0x00 0x8040000 0x00 0x10000  //  VGIC Virtual CPU Interface:     0x8040000
>;
compatible = "arm,cortex-a15-gic";
```

[(More about this)](https://www.kernel.org/doc/Documentation/devicetree/bindings/interrupt-controller/arm%2Cgic.txt)

We defined the Base Addresses in [arch/arm64/include/qemu/chip.h](https://github.com/lupyuen/incubator-nuttx/blob/gicv2/arch/arm64/include/qemu/chip.h#L38-L40)

Compare the above Base Addresses with the GIC v3 Device Tree: [gicv3.dts](https://github.com/lupyuen/incubator-nuttx/blob/gicv2/gicv3.dts#L324)

```text
intc@8000000 {
reg = <
    0x00 0x8000000 0x00 0x10000   //  GIC Distributor:   0x8000000
    0x00 0x80a0000 0x00 0xf60000  //  GIC CPU Interface: 0x80a0000
>;
#redistributor-regions = <0x01>;
compatible = "arm,gic-v3";
```

This is how we copied the PinePhone GIC v2 Source Files into NuttX QEMU Arm64 for testing...

```bash
cp ~/PinePhone/nuttx/nuttx/arch/arm64/src/common/arm64_gicv3.c      ~/gicv2/nuttx/nuttx/arch/arm64/src/common/arm64_gicv3.c
cp ~/PinePhone/nuttx/nuttx/arch/arm/src/armv7-a/arm_gicv2.c         ~/gicv2/nuttx/nuttx/arch/arm/src/armv7-a/arm_gicv2.c
cp ~/PinePhone/nuttx/nuttx/arch/arm/src/armv7-a/gic.h               ~/gicv2/nuttx/nuttx/arch/arm/src/armv7-a/gic.h
cp ~/PinePhone/nuttx/nuttx/arch/arm/src/armv7-a/arm_gicv2_dump.c    ~/gicv2/nuttx/nuttx/arch/arm/src/armv7-a/arm_gicv2_dump.c
cp ~/PinePhone/nuttx/nuttx/arch/arm64/src/common/arm64_arch_timer.c ~/gicv2/nuttx/nuttx/arch/arm64/src/common/arm64_arch_timer.c
```

## Handling Interrupts

Let's talk about NuttX and how it handles interrupts.

The __Interrupt Vector Table__ is defined in [sched/irq/irq_initialize.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/irq/irq_initialize.c#L47-L53)

```c
/* This is the interrupt vector table */
struct irq_info_s g_irqvector[NR_IRQS];
```

(Next section talks about dumping the Interrupt Vector Table)

At startup, the Interrupt Vector Table is initialised to the __Unexpected Interrupt Handler `irq_unexpected_isr`__: [sched/irq/irq_initialize.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/irq/irq_initialize.c#L59-L85)

```c
/****************************************************************************
 * Name: irq_initialize
 * Description:
 *   Configure the IRQ subsystem
 ****************************************************************************/
void irq_initialize(void)
{
  /* Point all interrupt vectors to the unexpected interrupt */
  for (i = 0; i < NR_IRQS; i++)
    {
      g_irqvector[i].handler = irq_unexpected_isr;
    }
  up_irqinitialize();
}
```

__Unexpected Interrupt Handler `irq_unexpected_isr`__ is called when an Interrupt is triggered and there's no Interrupt Handler attached to the Interrupt: [sched/irq/irq_unexpectedisr.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/irq/irq_unexpectedisr.c#L38-L59)

```c
/****************************************************************************
 * Name: irq_unexpected_isr
 * Description:
 *   An interrupt has been received for an IRQ that was never registered
 *   with the system.
 ****************************************************************************/
int irq_unexpected_isr(int irq, FAR void *context, FAR void *arg)
{
  up_irq_save();
  _err("ERROR irq: %d\n", irq);
  PANIC();
```

To __attach an Interrupt Handler__, we set the Handler and the Argument in the Interrupt Vector Table: [sched/irq/irq_attach.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/irq/irq_attach.c#L37-L136)

```c
/****************************************************************************
 * Name: irq_attach
 * Description:
 *   Configure the IRQ subsystem so that IRQ number 'irq' is dispatched to
 *   'isr'
 ****************************************************************************/
int irq_attach(int irq, xcpt_t isr, FAR void *arg)
{
  ...
  /* Save the new ISR and its argument in the table. */
  g_irqvector[irq].handler = isr;
  g_irqvector[irq].arg     = arg;
```

When an __Interrupt is triggered__...

1.  Arm CPU looks up the __Arm64 Vector Table `_vector_table`__: [arch/arm64/src/common/arm64_vector_table.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L93-L232)

```text
    /* Four types of exceptions:
    * - synchronous: aborts from MMU, SP/CP alignment checking, unallocated
    *   instructions, SVCs/SMCs/HVCs, ...)
    * - IRQ: group 1 (normal) interrupts
    * - FIQ: group 0 or secure interrupts
    * - SError: fatal system errors
    *
    * Four different contexts:
    * - from same exception level, when using the SP_EL0 stack pointer
    * - from same exception level, when using the SP_ELx stack pointer
    * - from lower exception level, when this is AArch64
    * - from lower exception level, when this is AArch32
    *
    * +------------------+------------------+-------------------------+
    * |     Address      |  Exception type  |       Description       |
    * +------------------+------------------+-------------------------+
    * | VBAR_ELn + 0x000 | Synchronous      | Current EL with SP0     |
    * |          + 0x080 | IRQ / vIRQ       |                         |
    * |          + 0x100 | FIQ / vFIQ       |                         |
    * |          + 0x180 | SError / vSError |                         |
    * +------------------+------------------+-------------------------+
    * |          + 0x200 | Synchronous      | Current EL with SPx     |
    * |          + 0x280 | IRQ / vIRQ       |                         |
    * |          + 0x300 | FIQ / vFIQ       |                         |
    * |          + 0x380 | SError / vSError |                         |
    * +------------------+------------------+-------------------------+
    * |          + 0x400 | Synchronous      | Lower EL using  AArch64 |
    * |          + 0x480 | IRQ / vIRQ       |                         |
    * |          + 0x500 | FIQ / vFIQ       |                         |
    * |          + 0x580 | SError / vSError |                         |
    * +------------------+------------------+-------------------------+
    * |          + 0x600 | Synchronous      | Lower EL using AArch64  |
    * |          + 0x680 | IRQ / vIRQ       |                         |
    * |          + 0x700 | FIQ / vFIQ       |                         |
    * |          + 0x780 | SError / vSError |                         |
    * +------------------+------------------+-------------------------+
    */
    GTEXT(_vector_table)
    SECTION_SUBSEC_FUNC(exc_vector_table,_vector_table_section,_vector_table)
        ...
        /* Current EL with SP0 / IRQ */
        .align 7
        arm64_enter_exception x0, x1
        b    arm64_irq_handler
        ...
        /* Current EL with SPx / IRQ */
        .align 7
        arm64_enter_exception x0, x1
        b    arm64_irq_handler
    ```

[(`arm64_enter_exception` is defined here)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L41-L87)

1.  Based on the Arm64 Vector Table `_vector_table`, Arm CPU jumps to `arm64_irq_handler`: [arch/arm64/src/common/arm64_vectors.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L326-L413)

```text
    /****************************************************************************
    * Name: arm64_irq_handler
    * Description:
    *   Interrupt exception handler
    ****************************************************************************/
    GTEXT(arm64_irq_handler)
    SECTION_FUNC(text, arm64_irq_handler)
        ...
        /* Call arm64_decodeirq() on the interrupt stack
        * with interrupts disabled
        */
        bl     arm64_decodeirq
    ```

1.  `arm64_irq_handler` calls `arm64_decodeirq` to decode the Interrupt: [arch/arm64/src/common/arm64_gicv3.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L800-L829)

```c
    /***************************************************************************
    * Name: arm64_decodeirq
    * Description:
    *   This function is called from the IRQ vector handler in arm64_vectors.S.
    *   At this point, the interrupt has been taken and the registers have
    *   been saved on the stack.  This function simply needs to determine the
    *   the irq number of the interrupt and then to call arm_doirq to dispatch
    *   the interrupt.
    *  Input Parameters:
    *   regs - A pointer to the register save area on the stack.
    ***************************************************************************/
    // Decode IRQ for PinePhone, based on arm_decodeirq in arm_gicv2.c
    uint64_t * arm64_decodeirq(uint64_t * regs)
    {
      ...
      if (irq < NR_IRQS)
        {
          /* Dispatch the interrupt */

regs = arm64_doirq(irq, regs);
    ```

1.  `arm64_decodeirq` calls `arm64_doirq` to dispatch the Interrupt: [arch/arm64/src/common/arm64_doirq.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_doirq.c#L64-L119)

```c
    /****************************************************************************
     * Name: arm64_doirq
    * Description:
    *   Receives the decoded GIC interrupt information and dispatches control
    *   to the attached interrupt handler.
    *
    ****************************************************************************/
    uint64_t *arm64_doirq(int irq, uint64_t * regs)
    {
      ...
      /* Deliver the IRQ */
      irq_dispatch(irq, regs);
    ```

1.  `irq_dispatch` calls the Interrupt Handler fetched from the Interrupt Vector Table: [sched/irq/irq_dispatch.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/irq/irq_dispatch.c#L115-L173)

```c
    /****************************************************************************
     * Name: irq_dispatch
    * Description:
    *   This function must be called from the architecture-specific logic in
    *   order to dispatch an interrupt to the appropriate, registered handling
    *   logic.
    ****************************************************************************/
    void irq_dispatch(int irq, FAR void *context)
    {
      if ((unsigned)irq < NR_IRQS)
        {
          if (g_irqvector[ndx].handler)
            {
              vector = g_irqvector[ndx].handler;
              arg    = g_irqvector[ndx].arg;
            }
        }
      /* Then dispatch to the interrupt handler */
      CALL_VECTOR(ndx, vector, irq, context, arg);
    ```

_How is the [Arm64 Vector Table `_vector_table`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L93-L232) configured in the Arm CPU?_

The [Arm64 Vector Table `_vector_table`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L93-L232) is configured in the Arm CPU during EL1 Init by `arm64_boot_el1_init`: [arch/arm64/src/common/arm64_boot.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L132-L162)

```c
void arm64_boot_el1_init(void)
{
  /* Setup vector table */
  write_sysreg((uint64_t)_vector_table, vbar_el1);
  ARM64_ISB();
```

`vbar_el1` refers to __Vector Base Address Register EL1__.

[(See Arm Cortex-A53 Technical Reference Manual, page 4-121, "Vector Base Address Register, EL1")](https://documentation-service.arm.com/static/5e9075f9c8052b1608761519?token=)

[(Arm64 Vector Table is also configured during EL3 Init by `arm64_boot_el3_init`)](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L39-L75)

EL1 Init `arm64_boot_el1_init` is called by our Startup Code: [arch/arm64/src/common/arm64_head.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L216-L230)

```text
    PRINT(switch_el1, "- Boot from EL1\r\n")

/* EL1 init */
    bl    arm64_boot_el1_init

/* set SP_ELx and Enable SError interrupts */
    msr   SPSel, #1
    msr   DAIFClr, #(DAIFCLR_ABT_BIT)
    isb

jump_to_c_entry:
    PRINT(jump_to_c_entry, "- Boot to C runtime for OS Initialize\r\n")
    ret x25
```

_What are EL1 and EL3?_

According to [Arm Cortex-A53 Technical Reference Manual](https://documentation-service.arm.com/static/5e9075f9c8052b1608761519?token=) page 3-5 ("Exception Level")...

> The ARMv8 exception model defines exception levels EL0-EL3, where:

> - EL0 has the lowest software execution privilege, and execution at EL0 is called unprivileged execution.

> - Increased exception levels, from 1 to 3, indicate increased software execution privilege.

> - EL2 provides support for processor virtualization.

> - EL3 provides support for a secure state, see Security state on page 3-6.

PinePhone only uses EL1 and EL2 (but not EL3)...

```text
HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
```

From this we see that NuttX runs mostly in EL1.

(EL1 is less privileged than EL2, which supports Processor Virtualization)

## Dump Interrupt Vector Table

This is how we dump the Interrupt Vector Table to troubleshoot Interrupts...

Based on [arch/arm64/src/common/arm64_arch_timer.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L210-L240)

```c
#include "irq/irq.h" // For dumping Interrupt Vector Table

void up_timer_initialize(void)
{
  ...
  // Attach System Timer Interrupt Handler
  irq_attach(ARM_ARCH_TIMER_IRQ, arm64_arch_timer_compare_isr, 0);

// Begin dumping Interrupt Vector Table
  sinfo("ARM_ARCH_TIMER_IRQ=%d\n", ARM_ARCH_TIMER_IRQ);
  sinfo("arm64_arch_timer_compare_isr=%p\n", arm64_arch_timer_compare_isr);
  sinfo("irq_unexpected_isr=%p\n", irq_unexpected_isr);
  for (int i = 0; i < NR_IRQS; i++)
    {
      sinfo("g_irqvector[%d].handler=%p\n", i, g_irqvector[i].handler);
    }
  // End dumping Interrupt Vector Table
```

This code runs at startup to attach the very first Interrupt Handler, for the [System Timer Interrupt](https://github.com/lupyuen/pinephone-nuttx#system-timer).

We see that the System Timer Interrupt Number (IRQ) is 27...

```text
up_timer_initialize: ARM_ARCH_TIMER_IRQ=27
up_timer_initialize: arm64_arch_timer_compare_isr=0x4009ae18
up_timer_initialize: irq_unexpected_isr=0x400820e0

up_timer_initialize: g_irqvector[0].handler=0x400820e0
...
up_timer_initialize: g_irqvector[26].handler=0x400820e0
up_timer_initialize: g_irqvector[27].handler=0x4009ae18
up_timer_initialize: g_irqvector[28].handler=0x400820e0
...
up_timer_initialize: g_irqvector[219].handler=0x400820e0
```

All entries in the Interrupt Vector Table point to the [Unexpected Interrupt Handler `irq_unexpected_isr`](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts), except for `g_irqvector[27]` which points to the [System Timer Interrupt Handler `arm64_arch_timer_compare_isr`](https://github.com/lupyuen/pinephone-nuttx#system-timer).

## Interrupt Debugging

_Can we debug the Arm64 Interrupt Handler?_

Yep we can write to the UART Port like this...

Based on [arch/arm64/src/common/arm64_vectors.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L326-L413)

```text
# PinePhone Allwinner A64 UART0 Base Address
#define UART1_BASE_ADDRESS 0x01C28000

# QEMU UART Base Address
# Previously: #define UART1_BASE_ADDRESS 0x9000000

/****************************************************************************
 * Name: arm64_irq_handler
 * Description:
 *   Interrupt exception handler
 ****************************************************************************/
GTEXT(arm64_irq_handler)
SECTION_FUNC(text, arm64_irq_handler)

mov   x0, #84                 /* For Debug: 'T' */
    ldr   x1, =UART1_BASE_ADDRESS /* For Debug */
    strb  w0, [x1]                /* For Debug */

/* switch to IRQ stack and save current sp on it. */
    ...
```

This will print "T" on the console whenever the Arm64 CPU triggers an Interrupt. (Assuming that the UART Buffer hasn't overflowed)

We can insert this debug code for every handler in [arch/arm64/src/common/arm64_vectors.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S)...

-   [`arm64_sync_exc`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L172-L324): Handle synchronous exception

-   [`arm64_irq_handler`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L326-L413): Interrupt exception handler

-   [`arm64_serror_handler`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L401-L413): SError handler (Fatal System Errors)

-   [`arm64_mode32_error`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L415-L425): Mode32 Error

-   [`arm64_irq_spurious`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S#L427-L438): Spurious Interrupt

This is how we insert the debug code for every handler in [arm64_vectors.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vectors.S): https://gist.github.com/lupyuen/4bea83c61704080f1af18abfda63c77e

We can do the same for the __Arm64 Vector Table__: [arch/arm64/src/common/arm64_vector_table.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_vector_table.S#L47-L75)

```text
# PinePhone Allwinner A64 UART0 Base Address
#define UART1_BASE_ADDRESS 0x01C28000

# QEMU UART Base Address
# Previously: #define UART1_BASE_ADDRESS 0x9000000

/* Save Corruptible Registers and exception context
 * on the task stack
 * note: allocate stackframe with XCPTCONTEXT_GP_REGS
 *     which is ARM64_ESF_REGS + ARM64_CS_REGS
 *     but only save ARM64_ESF_REGS
 */
.macro arm64_enter_exception xreg0, xreg1
    sub    sp, sp, #8 * XCPTCONTEXT_GP_REGS

stp    x0,  x1,  [sp, #8 * REG_X0]
    stp    x2,  x3,  [sp, #8 * REG_X2]
    ...
    stp    x28, x29, [sp, #8 * REG_X28]

mov   x0, #88                 /* For Debug: 'X' */
    ldr   x1, =UART1_BASE_ADDRESS /* For Debug */
    strb  w0, [x1]                /* For Debug */
```

## Memory Map

PinePhone depends on Arm's Memory Management Unit (MMU). We defined two MMU Memory Regions for PinePhone: RAM and Device I/O: [arch/arm64/include/qemu/chip.h](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/include/qemu/chip.h#L38-L62)

```c
// PinePhone Generic Interrupt Controller
// GIC_DIST:  0x01C80000 + 0x1000
// GIC_CPUIF: 0x01C80000 + 0x2000
#define CONFIG_GICD_BASE          0x01C81000  
#define CONFIG_GICR_BASE          0x01C82000

// Previously:
// #define CONFIG_GICD_BASE          0x8000000
// #define CONFIG_GICR_BASE          0x80a0000

// PinePhone RAM: 0x4000 0000 to 0x4800 0000
#define CONFIG_RAMBANK1_ADDR      0x40000000
#define CONFIG_RAMBANK1_SIZE      MB(128)

// PinePhone Device I/O: 0x0 to 0x2000 0000
#define CONFIG_DEVICEIO_BASEADDR  0x00000000
#define CONFIG_DEVICEIO_SIZE      MB(512)

// Previously:
// #define CONFIG_DEVICEIO_BASEADDR  0x7000000
// #define CONFIG_DEVICEIO_SIZE      MB(512)

// PinePhone uboot load address (kernel_addr_r)
#define CONFIG_LOAD_BASE          0x40080000
// Previously: #define CONFIG_LOAD_BASE          0x40280000
```

We also changed CONFIG_LOAD_BASE for PinePhone's Kernel Start Address (kernel_addr_r).

_How are the MMU Memory Regions used?_

NuttX initialises the Arm MMU with the MMU Memory Regions at startup: [arch/arm64/src/qemu/qemu_boot.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_boot.c#L52-L67)

```c
static const struct arm_mmu_region mmu_regions[] =
{
  MMU_REGION_FLAT_ENTRY("DEVICE_REGION",
                        CONFIG_DEVICEIO_BASEADDR, MB(512),
                        MT_DEVICE_NGNRNE | MT_RW | MT_SECURE),

MMU_REGION_FLAT_ENTRY("DRAM0_S0",
                        CONFIG_RAMBANK1_ADDR, MB(512),
                        MT_NORMAL | MT_RW | MT_SECURE),
};

const struct arm_mmu_config mmu_config =
{
  .num_regions = ARRAY_SIZE(mmu_regions),
  .mmu_regions = mmu_regions,
};
```

The Arm MMU Initialisation is done by `arm64_mmu_init`, defined in [arch/arm64/src/common/arm64_mmu.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_mmu.c#L571-L622)

We'll talk more about the Arm MMU in the next section...

## Boot Sequence

Read the article...

-   ["PinePhone Boots NuttX"](https://lupyuen.github.io/articles/unicorn2#pinephone-boots-nuttx)

-   ["PinePhone Continues Booting NuttX"](https://lupyuen.github.io/articles/unicorn2#pinephone-continues-booting-nuttx)

-   ["Start NSH Shell"](https://lupyuen.github.io/articles/unicorn2#appendix-start-nsh-shell)

This section describes the Boot Sequence for NuttX on PinePhone...

1.  [Startup Code](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L117-L176) (in Arm64 Assembly) inits the Arm64 System Registers and UART Port.

1.  [Startup Code](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L178-L182) prints the Hello Message...

```text
    HELLO NUTTX ON PINEPHONE!
    Ready to Boot CPU
    ```

1.  [Startup Code](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L199-L213) calls [`arm64_boot_el2_init`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L91-L130) to Init EL2

```text
    Boot from EL2
    ```

1.  [Startup Code](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L215-L226) calls [`arm64_boot_el1_init`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L132-L162) to Init EL1 and load the [Vector Base Address Register EL1](https://github.com/lupyuen/pinephone-nuttx#handling-interrupts)

```text
    Boot from EL1
    ```

1.  [Startup Code](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L228-L230) jumps to `arm64_boot_secondary_c_routine`: [arch/arm64/src/common/arm64_head.S](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_head.S#L228-L230)

```text
        ldr    x25, =arm64_boot_secondary_c_routine
        ...
    jump_to_c_entry:
        PRINT(jump_to_c_entry, "- Boot to C runtime for OS Initialize\r\n")
        ret x25
    ```

Which appears as...

```text
    Boot to C runtime for OS Initialize
    ```

1.  TODO: Who calls `qemu_pl011_setup` to init the UART Port?

1.  `arm64_boot_primary_c_routine` inits the BSS, calls `arm64_chip_boot` to init the Arm64 CPU, and `nx_start` to start the NuttX processes: [arch/arm64/src/common/arm64_boot.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L179-L189)

```c
    void arm64_boot_primary_c_routine(void)
    {
      boot_early_memset(_START_BSS, 0, _END_BSS - _START_BSS);
      arm64_chip_boot();
      nx_start();
    }
    ```

Which appears as...

```text
    nx_start: Entry
    ```

1.  `arm64_chip_boot` calls `arm64_mmu_init` to enable the Arm Memory Management Unit, and `qemu_board_initialize` to init the Board Drivers: [arch/arm64/src/qemu/qemu_boot.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_boot.c#L81-L105)

```c
    void arm64_chip_boot(void)
    {
      /* MAP IO and DRAM, enable MMU. */

arm64_mmu_init(true);

#ifdef CONFIG_SMP
      arm64_psci_init("smc");

#endif

/* Perform board-specific device initialization. This would include
      * configuration of board specific resources such as GPIOs, LEDs, etc.
      */

qemu_board_initialize();

#ifdef USE_EARLYSERIALINIT
      /* Perform early serial initialization if we are going to use the serial
      * driver.
      */

qemu_earlyserialinit();
    #endif
    }
    ```

`arm64_mmu_init` is defined in [arch/arm64/src/common/arm64_mmu.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_mmu.c#L571-L622)

1.  TODO: Who calls `up_allocate_heap` to allocate the heap?

```text
    up_allocate_heap: heap_start=0x0x400c4000, heap_size=0x7f3c000
    ```

1.  TODO: Who calls [`arm64_gic_initialize`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_gicv3.c#L710-L734) to init the GIC?

```text
    arm64_gic_initialize: TODO: Init GIC for PinePhone
    arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
    arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
    arm64_gic_initialize: GIC Version is 2
    ```

1.  TODO: Who calls [`up_timer_initialize`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_arch_timer.c#L212-L235) to start the System Timer?

1.  TODO: Who calls `uart_register` to register `/dev/console` and `/dev/ttyS0`?

1.  TODO: Who calls `qemu_pl011_attach` to Attach UART Interrupt and `qemu_pl011_rxint` to Enable UART Receive Interrupt?

1.  TODO: Who calls `work_start_highpri` to start high-priority kernel worker thread(s)?

1.  TODO: Who calls `nx_start_application` to starting init thread?

1.  TODO: Who calls `nxtask_start` to start the NuttX Shell?

1.  [`nxtask_start`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/sched/task/task_start.c#L60-L145) calls [`nxtask_startup`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/sched/task_startup.c#L40-L71) to start the NuttX Shell

1.  [`nxtask_startup`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/sched/task_startup.c#L40-L71) calls [`lib_cxx_initialize`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/misc/lib_cxx_initialize.c#L68-L123) to init the C++ Constructors.

```text
    lib_cxx_initialize: _sinit: 0x400a7000 _einit: 0x400a7000 _stext: 0x40080000 _etext: 0x400a8000
    ```

Then [`nxtask_startup`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/sched/task_startup.c#L40-L71) calls the Main Entry Point for the NuttX Shell, [`entrypt`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/sched/task_startup.c#L66-L70)

1.  [`entrypt`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/libs/libc/sched/task_startup.c#L66-L70) points to [`nsh_main`](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/system/nsh/nsh_main.c#L87-L165), the Main Function for the NuttX Shell

1.  [`nsh_main`](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/system/nsh/nsh_main.c#L87-L165), starts the NuttX Shell.

UART Transmit and Receive Interrupts must work, otherwise nothing appears in NuttX Shell.

(Because NuttX Shell calls Stream I/O with the Serial Driver)

1.  TODO: Who calls `qemu_pl011_txint` to Enable UART Transmit Interrupt?

```text
    HHHHHHHHHHHH: qemu_pl011_txint
    ```

1.  TODO: Who calls `qemu_pl011_rxint` to Enable UART Receive Interrupt?

```text
    GG: qemu_pl011_rxint
    ```

1.  `nx_start` starts the Idle Loop

```text
    nx_start: CPU0: Beginning Idle Loop
    ```

The next section talks about debugging the Boot Sequence...

## Boot Debugging

_How can we debug NuttX while it boots?_

We may call `up_putc` to print characters to the Serial Console and troubleshoot the Boot Sequence: [arch/arm64/src/common/arm64_boot.c](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/common/arm64_boot.c#L179-L189)

```c
void arm64_boot_primary_c_routine(void)
{
  int up_putc(int ch);  // For debugging
  up_putc('0');  // For debugging
  boot_early_memset(_START_BSS, 0, _END_BSS - _START_BSS);
  up_putc('1');  // For debugging
  arm64_chip_boot();
  up_putc('2');  // For debugging
  nx_start();
}
```

This prints "012" to the Serial Console as NuttX boots.

[`up_putc`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_serial.c#L924-L946) calls [`up_lowputc`](https://github.com/lupyuen/incubator-nuttx/blob/pinephone/arch/arm64/src/qemu/qemu_lowputc.S#L100-L109) to print directly to the UART Port by writing to the UART Register. So it's safe to be called as NuttX boots.

## UART Interrupts

Previously we noticed that NuttX Shell wasn't generating output on the Serial Console.

We discovered that `sinfo` (`syslog`) works, but `printf` (`puts`) doesn't!

Here's what we tested with NuttX Shell: [system/nsh/nsh_main.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/system/nsh/nsh_main.c#L88-L102)

```c
/****************************************************************************
 * Name: nsh_main
 *
 * Description:
 *   This is the main logic for the case of the NSH task.  It will perform
 *   one-time NSH initialization and start an interactive session on the
 *   current console device.
 *
 ****************************************************************************/

int main(int argc, FAR char *argv[])
{
  sinfo("****main\n");////
  printf("****main2\n");////
  sinfo("****main3\n");////
```

`main2` never appears in the output because UART Transmit Interrupts (`qemu_pl011_txint`) haven't been implemented...

```text
nsh_main: ****main
HH: qemu_pl011_txint
nsh_main: ****main3
```

This is the sequence of calls to `qemu_pl011_attach`, `qemu_pl011_rxint` and `qemu_pl011_txint` for UART Transmit and Receive Interrupts...

```text
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
K: qemu_pl011_attach
G: qemu_pl011_rxint
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400a7000 _einit: 0x400a7000 _stext: 0x40080000 _etext: 0x400a8000
nsh_main: ****main
puts: A
HH: qemu_pl011_txint
puts: B
nsh_main: ****main3
HHHHHHHHHHHH: qemu_pl011_txint
GG: qemu_pl011_rxint
nx_start: CPU0: Beginning Idle Loop
```

We need to implement UART Transmit and Receive Interrupts to support NuttX Shell.

Here's our implementation...

-   ["NuttX RTOS on PinePhone: UART Driver"](https://lupyuen.github.io/articles/serial)

# Backlight and LEDs

Read the article...

-   ["NuttX RTOS for PinePhone: Blinking the LEDs"](https://lupyuen.github.io/articles/pio)

Let's light up the PinePhone Backlight and the Red / Green / Blue LEDs.

Based on the [PinePhone Schematic](https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf)...

-   Backlight Enable is connected to GPIO PH10

(PH10-LCD-BL-EN)

-   Backlight PWM is connected to PWM PL10

(PL10-LCD-PWM)

This is how we turn on GPIO PH10 in Allwinner A64 Port Controller (PIO): [examples/hello/hello_main.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/examples/hello/hello_main.c#L83-L122)

```c
// PIO Base Address for PinePhone Allwinner A64 Port Controller (GPIO)
#define PIO_BASE_ADDRESS 0x01C20800

// Turn on the PinePhone Backlight
static void test_backlight(void)
{
  // From PinePhone Schematic: https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf
  // - Backlight Enable: GPIO PH10 (PH10-LCD-BL-EN)
  // - Backlight PWM:    PWM  PL10 (PL10-LCD-PWM)
  // We won't handle the PWM yet

// Write to PH Configure Register 1 (PH_CFG1_REG)
  // Offset: 0x100
  uint32_t *ph_cfg1_reg = (uint32_t *)
    (PIO_BASE_ADDRESS + 0x100);

// Bits 10 to 8: PH10_SELECT (Default 0x7)
  // 000: Input     001: Output
  // 010: MIC_CLK   011: Reserved
  // 100: Reserved  101: Reserved
  // 110: PH_EINT10 111: IO Disable
  *ph_cfg1_reg = 
    (*ph_cfg1_reg & ~(0b111 << 8))  // Clear the bits
    | (0b001 << 8);                 // Set the bits for Output
  printf("ph_cfg1_reg=0x%x\n", *ph_cfg1_reg);

// Write to PH Data Register (PH_DATA_REG)
  // Offset: 0x10C
  uint32_t *ph_data_reg = (uint32_t *)
    (PIO_BASE_ADDRESS + 0x10C);

// Bits 11 to 0: PH_DAT (Default 0)
  // If the port is configured as input, the corresponding bit is the pin state. If
  // the port is configured as output, the pin state is the same as the
  // corresponding bit. The read bit value is the value setup by software.
  // If the port is configured as functional pin, the undefined value will
  // be read.
  *ph_data_reg |= (1 << 10);  // Set Bit 10 for PH10
  printf("ph_data_reg=0x%x\n", *ph_data_reg);
}
```

The Backlight lights up and the output shows...

```text
ph_cfg1_reg=0x7177
ph_data_reg=0x400
```

Now for the LEDs. Based on the [PinePhone Schematic](https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf)...

-   Red LED is connected to GPIO PD18

(PD18-LED-R)

-   Green LED is connected to GPIO PD19

(PD19-LED-G)

-   Blue LED is connected to GPIO PD20

(PD20-LED-B)

This is how we turn on GPIOs PD18, PD19, PD20 in Allwinner A64 Port Controller (PIO): [examples/hello/hello_main.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/examples/hello/hello_main.c#L124-L179)

```c
// PIO Base Address for PinePhone Allwinner A64 Port Controller (GPIO)
#define PIO_BASE_ADDRESS 0x01C20800

// Turn on the PinePhone Red, Green and Blue LEDs
static void test_led(void)
{
  // From PinePhone Schematic: https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf
  // - Red LED:   GPIO PD18 (PD18-LED-R)
  // - Green LED: GPIO PD19 (PD19-LED-G)
  // - Blue LED:  GPIO PD20 (PD20-LED-B)

// Write to PD Configure Register 2 (PD_CFG2_REG)
  // Offset: 0x74
  uint32_t *pd_cfg2_reg = (uint32_t *)
    (PIO_BASE_ADDRESS + 0x74);

// Bits 10 to 8: PD18_SELECT (Default 0x7)
  // 000: Input    001: Output
  // 010: LCD_CLK  011: LVDS_VPC
  // 100: RGMII_TXD0/MII_TXD0/RMII_TXD0 101: Reserved
  // 110: Reserved 111: IO Disable
  *pd_cfg2_reg = 
    (*pd_cfg2_reg & ~(0b111 << 8))  // Clear the bits
    | (0b001 << 8);                 // Set the bits for Output

// Bits 14 to 12: PD19_SELECT (Default 0x7)
  // 000: Input    001: Output
  // 010: LCD_DE   011: LVDS_VNC
  // 100: RGMII_TXCK/MII_TXCK/RMII_TXCK 101: Reserved
  // 110: Reserved 111: IO Disable
  *pd_cfg2_reg = 
    (*pd_cfg2_reg & ~(0b111 << 12))  // Clear the bits
    | (0b001 << 12);                 // Set the bits for Output

// Bits 18 to 16: PD20_SELECT (Default 0x7)
  // 000: Input     001: Output
  // 010: LCD_HSYNC 011: LVDS_VP3
  // 100: RGMII_TXCTL/MII_TXEN/RMII_TXEN 101: Reserved
  // 110: Reserved  111: IO Disable
  *pd_cfg2_reg = 
    (*pd_cfg2_reg & ~(0b111 << 16))  // Clear the bits
    | (0b001 << 16);                 // Set the bits for Output
  printf("pd_cfg2_reg=0x%x\n", *pd_cfg2_reg);

// Write to PD Data Register (PD_DATA_REG)
  // Offset: 0x7C
  uint32_t *pd_data_reg = (uint32_t *)
    (PIO_BASE_ADDRESS + 0x7C);

// Bits 24 to 0: PD_DAT (Default 0)
  // If the port is configured as input, the corresponding bit is the pin state. If
  // the port is configured as output, the pin state is the same as the
  // corresponding bit. The read bit value is the value setup by software. If the
  // port is configured as functional pin, the undefined value will be read.
  *pd_data_reg |= (1 << 18);  // Set Bit 18 for PD18
  *pd_data_reg |= (1 << 19);  // Set Bit 19 for PD19
  *pd_data_reg |= (1 << 20);  // Set Bit 20 for PD20
  printf("pd_data_reg=0x%x\n", *pd_data_reg);
}
```

The Red, Green and Blue LEDs turn on (appearing as white) and the output shows...

```text
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
```

[__Watch the Demo on YouTube__](https://youtu.be/MJDxCcKAv0g)

Here's the complete log for [examples/hello/hello_main.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/examples/hello/hello_main.c)...

```text
nsh> hello
task_spawn: name=hello entry=0x4009b1a4 file_actions=0x400c9580 attr=0x400c9588 argv=0x400c96d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
tcon_gctl_reg=0x80000000
tcon0_3d_fifo_reg=0x80000631
tcon0_ctl_reg=0x80000000
tcon0_basic0_reg=0x630063
tcon0_lvds_if_reg=0x80000000
nsh> 
```

## BASIC Blinks The LEDs

In the previous section we lit up PinePhone's Red, Green and Blue LEDs. Below are the values we wrote to the Allwinner A64 Port Controller...

```text
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
```

Let's do the same in BASIC! Which is great for interactive experimenting with PinePhone Hardware.

This will enable GPIO Output for PD18 (Red), PD19 (Green), PD20 (Blue) in the Register `pd_cfg2_reg` (0x1C20874)...

```text
poke &h1C20874, &h77711177
```

This will light up Red, Green and Blue LEDs via the Register `pd_data_reg` (0x1C2087C)...

```text
poke &h1C2087C, &h1C0000
```

And this will turn off all 3 LEDs via `pd_data_reg` (0x1C2087C)...

```text
poke &h1C2087C, &h0000
```

Install the BASIC Interpreter in NuttX...

-   ["Enable BASIC"](https://lupyuen.github.io/articles/nuttx#enable-basic)

And enter these commands to blink the PinePhone LEDs (off and on)...

[__Watch the Demo on YouTube__](https://youtu.be/OTIHMIRd1s4)

```text
nsh> bas
task_spawn: name=bas entry=0x4009b340 file_actions=0x400f3580 attr=0x400f3588 argv=0x400f36d0
spawn_execattrs: Setting policy=2 priority=100 for pid=7
bas 2.4
Copyright 1999-2014 Michael Haardt.
This is free software with ABSOLUTELY NO WARRANTY.

> print peek(&h1C20874)
 2004316535

> poke &h1C20874, &h77711177

> print peek(&h1C20874)
 2003898743

> print peek(&h1C2087C)
 262144

> poke &h1C2087C, &h0000

> print peek(&h1C2087C)
 0

> poke &h1C2087C, &h1C0000

> print peek(&h1C2087C)
 1835008  
```

Or run it in a loop like so...

```text
10 'Enable GPIO Output for PD18, PD19 and PD20
20 poke &h1C20874, &h77711177
30 'Turn off GPIOs PD18, PD19 and PD20
40 poke &h1C2087C, &h0
50 sleep 5
60 'Turn on GPIOs PD18, PD19 and PD20
70 poke &h1C2087C, &h1C0000
80 sleep 5
90 goto 40
run
```

We patched NuttX BASIC so that it supports `peek` and `poke`: [interpreters/bas/bas_fs.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/interpreters/bas/bas_fs.c#L1862-L1889)

```c
int FS_memInput(int address)
{
  //  Return the 32-bit word at the specified address.
  //  TODO: Quit if address is invalid.
  return *(int *)(uint64_t) address;

//  Previously:
  //  FS_errmsg = _("Direct memory access not available");
  //  return -1;
}

int FS_memOutput(int address, int value)
{
  //  Set the 32-bit word at the specified address
  //  TODO: Quit if address is invalid.
  *(int *)(uint64_t) address = value;
  return 0;

//  Previously:
  //  FS_errmsg = _("Direct memory access not available");
  //  return -1;
}
```

Note that addresses are passed as 32-bit `int`, so some 64-bit addresses will not be accessible via `peek` and `poke`.

## NuttX Drivers for Allwinner A64 PIO and PinePhone LEDs

We built the NuttX Driver for Allwinner A64 PIO (Programmable I/O)...

-   [arch/arm64/src/a64/a64_pio.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/pio/arch/arm64/src/a64/a64_pio.c)

Which is based on the existing NuttX Driver for Allwinner A10 PIO...

-   [arch/arm/src/a1x/a1x_pio.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/pio/arch/arm/src/a1x/a1x_pio.c)

By calling the PIO Driver, we created the NuttX Driver for PinePhone Red / Green / Blue LEDs...

-   [boards/arm64/a64/pinephone/src/pinephone_autoleds.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/pio/boards/arm64/a64/pinephone/src/pinephone_autoleds.c)

-   [boards/arm64/a64/pinephone/src/pinephone_userleds.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/pio/boards/arm64/a64/pinephone/src/pinephone_userleds.c)

We tested the LED Driver with the `leds` Test App, here's the Test Log...

-   [nuttx-pinephone-led.log](https://gist.github.com/lupyuen/b9de190aba4598752d827f1105571a6a)

From the Test Log we see the Red / Green / Blue LEDs set to the colour combinations...

```text
led_daemon: LED set 0x00 (black)
led_daemon: LED set 0x01 (green)
led_daemon: LED set 0x02 (red)
led_daemon: LED set 0x03 (yellow)
led_daemon: LED set 0x04 (blue)
led_daemon: LED set 0x05 (cyan)
led_daemon: LED set 0x06 (magenta)
led_daemon: LED set 0x07 (white)
```

PinePhone PIO and LEDs are now supported in NuttX Mainline...

https://github.com/apache/nuttx/pull/7796

# PinePhone Device Tree

Let's figure out how Allwinner A64's Display Timing Controller (TCON0) talks to PinePhone's MIPI DSI Display. (So we can build NuttX Drivers)

More info on PinePhone Display...

-   ["Genode Operating System Framework 22.05"](https://genode.org/documentation/genode-platforms-22-05.pdf), pages 171 to 197.

We tried tweaking the TCON0 Controller but the display is still blank (maybe backlight is off?)

-   [examples/hello/hello_main.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/pinephone/examples/hello/hello_main.c#L75-L234)

Below is the Device Tree for PinePhone's Linux Kernel...

-   [PinePhone Device Tree: sun50i-a64-pinephone-1.2.dts](sun50i-a64-pinephone-1.2.dts)

We converted the Device Tree with this command...

```
## Convert Device Tree to text format
dtc \
  -o sun50i-a64-pinephone-1.2.dts \
  -O dts \
  -I dtb \
  sun50i-a64-pinephone-1.2.dtb
```

`sun50i-a64-pinephone-1.2.dtb` came from the [Jumpdrive microSD](https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive).

High-level doc of Linux Drivers...

-   [devicetree/bindings/display/sunxi/sun4i-drm.txt](https://www.kernel.org/doc/Documentation/devicetree/bindings/display/sunxi/sun4i-drm.txt)

PinePhone Schematic shows the connections for Display, Touch Panel and Backlight...

-   [PinePhone v1.2b Released Schematic](https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf)

Here are the interesting bits from the PinePhone Linux Device Tree: [sun50i-a64-pinephone-1.2.dts](sun50i-a64-pinephone-1.2.dts)

## LCD Controller (TCON0)

```text
lcd-controller@1c0c000 {
  compatible = "allwinner,sun50i-a64-tcon-lcd\0allwinner,sun8i-a83t-tcon-lcd";
  reg = <0x1c0c000 0x1000>;
  interrupts = <0x00 0x56 0x04>;
  clocks = <0x02 0x2f 0x02 0x64>;
  clock-names = "ahb\0tcon-ch0";
  clock-output-names = "tcon-pixel-clock";
  #clock-cells = <0x00>;
  resets = <0x02 0x18 0x02 0x23>;
  reset-names = "lcd\0lvds";

ports {
    #address-cells = <0x01>;
    #size-cells = <0x00>;

// TCON0: MIPI DSI Display
    port@0 {
      #address-cells = <0x01>;
      #size-cells = <0x00>;
      reg = <0x00>;

endpoint@0 {
        reg = <0x00>;
        remote-endpoint = <0x22>;
        phandle = <0x1e>;
      };

endpoint@1 {
        reg = <0x01>;
        remote-endpoint = <0x23>;
        phandle = <0x20>;
      };
    };

// TCON1: HDMI
    port@1 { ... };
  };
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L446-L492)

## MIPI DSI Interface

```text
dsi@1ca0000 {
  compatible = "allwinner,sun50i-a64-mipi-dsi";
  reg = <0x1ca0000 0x1000>;
  interrupts = <0x00 0x59 0x04>;
  clocks = <0x02 0x1c>;
  resets = <0x02 0x05>;
  phys = <0x53>;
  phy-names = "dphy";
  status = "okay";
  #address-cells = <0x01>;
  #size-cells = <0x00>;
  vcc-dsi-supply = <0x45>;

port {

endpoint {
      remote-endpoint = <0x54>;
      phandle = <0x24>;
    };
  };

panel@0 {
    compatible = "xingbangda,xbd599";
    reg = <0x00>;
    reset-gpios = <0x2b 0x03 0x17 0x01>;
    iovcc-supply = <0x55>;
    vcc-supply = <0x48>;
    backlight = <0x56>;
  };
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1327-L1356)

## Display PHY

```text
d-phy@1ca1000 {
  compatible = "allwinner,sun50i-a64-mipi-dphy\0allwinner,sun6i-a31-mipi-dphy";
  reg = <0x1ca1000 0x1000>;
  clocks = <0x02 0x1c 0x02 0x71>;
  clock-names = "bus\0mod";
  resets = <0x02 0x05>;
  status = "okay";
  #phy-cells = <0x00>;
  phandle = <0x53>;
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1358-L1367)

## Backlight PWM

```text
backlight {
  compatible = "pwm-backlight";
  pwms = <0x62 0x00 0xc350 0x01>;
  enable-gpios = <0x2b 0x07 0x0a 0x00>;
  power-supply = <0x48>;
  brightness-levels = <0x1388 0x1480 0x1582 0x16e2 0x18c9 0x1b4b 0x1e7d 0x2277 0x274e 0x2d17 0x33e7 0x3bd5 0x44f6 0x4f5f 0x5b28 0x6864 0x7729 0x878e 0x99a7 0xad8b 0xc350>;
  num-interpolated-steps = <0x32>;
  default-brightness-level = <0x1f4>;
  phandle = <0x56>;
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1832-L1841)

From [PinePhone Schematic](https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf)...

-   Backlight Enable: GPIO PH10 (PH10-LCD-BL-EN)

-   Backlight PWM: PWM PL10 (PL10-LCD-PWM)

## LED

```text
leds {
  compatible = "gpio-leds";

blue {
    function = "indicator";
    color = <0x03>;
    gpios = <0x2b 0x03 0x14 0x00>;
    retain-state-suspended;
  };

green {
    function = "indicator";
    color = <0x02>;
    gpios = <0x2b 0x03 0x12 0x00>;
    retain-state-suspended;
  };

red {
    function = "indicator";
    color = <0x01>;
    gpios = <0x2b 0x03 0x13 0x00>;
    retain-state-suspended;
  };
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1940-L1963)

From [PinePhone Schematic](https://files.pine64.org/doc/PinePhone/PinePhone%20v1.2b%20Released%20Schematic.pdf)...

-   Red LED: GPIO PD18 (PD18-LED-R)

-   Green LED: GPIO PD19 (PD19-LED-G)

-   Blue LED: GPIO PD20 (PD20-LED-B)

## Framebuffer

```text
framebuffer-lcd {
  compatible = "allwinner,simple-framebuffer\0simple-framebuffer";
  allwinner,pipeline = "mixer0-lcd0";
  clocks = <0x02 0x64 0x03 0x06>;
  status = "disabled";
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L16-L21)

## Display Engine

```text
display-engine {
  compatible = "allwinner,sun50i-a64-display-engine";
  allwinner,pipelines = <0x07 0x08>;
  status = "okay";
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L98-L102)

## Touch Panel

```text
touchscreen@5d {
  compatible = "goodix,gt917s";
  reg = <0x5d>;
  interrupt-parent = <0x2b>;
  interrupts = <0x07 0x04 0x04>;
  irq-gpios = <0x2b 0x07 0x04 0x00>;
  reset-gpios = <0x2b 0x07 0x0b 0x00>;
  AVDD28-supply = <0x48>;
  VDDIO-supply = <0x48>;
  touchscreen-size-x = <0x2d0>;
  touchscreen-size-y = <0x5a0>;
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1125-L1136)

## Video Codec

```text
video-codec@1c0e000 {
  compatible = "allwinner,sun50i-a64-video-engine";
  reg = <0x1c0e000 0x1000>;
  clocks = <0x02 0x2e 0x02 0x6a 0x02 0x5f>;
  clock-names = "ahb\0mod\0ram";
  resets = <0x02 0x17>;
  interrupts = <0x00 0x3a 0x04>;
  allwinner,sram = <0x28 0x01>;
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L539-L547)

## GPU

```text
gpu@1c40000 {
  compatible = "allwinner,sun50i-a64-mali\0arm,mali-400";
  reg = <0x1c40000 0x10000>;
  interrupts = <0x00 0x61 0x04 0x00 0x62 0x04 0x00 0x63 0x04 0x00 0x64 0x04 0x00 0x66 0x04 0x00 0x67 0x04 0x00 0x65 0x04>;
  interrupt-names = "gp\0gpmmu\0pp0\0ppmmu0\0pp1\0ppmmu1\0pmu";
  clocks = <0x02 0x35 0x02 0x72>;
  clock-names = "bus\0core";
  resets = <0x02 0x1f>;
  assigned-clocks = <0x02 0x72>;
  assigned-clock-rates = <0x1dcd6500>;
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1246-L1256)

## Deinterlace

```text
deinterlace@1e00000 {
  compatible = "allwinner,sun50i-a64-deinterlace\0allwinner,sun8i-h3-deinterlace";
  reg = <0x1e00000 0x20000>;
  clocks = <0x02 0x31 0x02 0x66 0x02 0x61>;
  clock-names = "bus\0mod\0ram";
  resets = <0x02 0x1a>;
  interrupts = <0x00 0x5d 0x04>;
  interconnects = <0x57 0x09>;
  interconnect-names = "dma-mem";
};
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L1369-L1378)

# Zig on PinePhone

Let's run this Zig App on NuttX for PinePhone: [display.zig](display.zig)

In NuttX, enable the Null Example App: make menuconfig, select "Application Configuration" > "Examples" > "Null Example"

Compile the Zig App (based on the GCC Compiler Options, see below)...

```bash
#  Change "$HOME/nuttx" for your NuttX Project Directory
cd $HOME/nuttx

#  Download the Zig App
git clone --recursive https://github.com/lupyuen/pinephone-nuttx
cd pinephone-nuttx

#  Compile the Zig App for PinePhone 
#  (armv8-a with cortex-a53)
#  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
zig build-obj \
  --verbose-cimport \
  -target aarch64-freestanding-none \
  -mcpu cortex_a53 \
  -isystem "$HOME/nuttx/nuttx/include" \
  -I "$HOME/nuttx/apps/include" \
  display.zig

#  Copy the compiled app to NuttX and overwrite `null.o`
#  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
cp display.o \
  $HOME/nuttx/apps/examples/null/*null.o

#  Build NuttX to link the Zig Object from `null.o`
#  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
cd $HOME/nuttx/nuttx
make
```

Run the Zig App...

```text
nsh> null
HELLO ZIG ON PINEPHONE!
```

_How did we get the Zig Compiler options `-target`, `-mcpu`, `-isystem` and `-I`?_

`make --trace` shows these GCC Compiler Options when building Nuttx for PinePhone...

```bash
aarch64-none-elf-gcc
  -c
  -fno-common
  -Wall
  -Wstrict-prototypes
  -Wshadow
  -Wundef
  -Werror
  -Os
  -fno-strict-aliasing
  -fomit-frame-pointer
  -g
  -march=armv8-a
  -mtune=cortex-a53
  -isystem "/Users/Luppy/PinePhone/nuttx/nuttx/include"
  -D__NuttX__ 
  -pipe
  -I "/Users/Luppy/PinePhone/nuttx/apps/include"
  -Dmain=hello_main  hello_main.c
  -o  hello_main.c.Users.Luppy.PinePhone.nuttx.apps.examples.hello.o
```

We copied and modified these GCC Compiler Options for Zig.

_What about `-D__NuttX__`?_

The Zig Compiler won't let us specify C Macros at the Command Line, so we defined the macro `__NuttX__` in our Zig App...

https://github.com/lupyuen/pinephone-nuttx/blob/2d938b9f09a165c0ff82b5dbbb12f1c4c6db61f2/display.zig#L27-L42

# PinePhone Display Driver

Read the articles...

-   ["NuttX RTOS for PinePhone: MIPI Display Serial Interface"](https://lupyuen.github.io/articles/dsi3)

-   ["NuttX RTOS for PinePhone: Display Engine"](https://lupyuen.github.io/articles/de3)

Let's talk about the NuttX Driver for PinePhone MIPI DSI, Display Engine and Timing Controller...

## Zig Driver for PinePhone MIPI DSI

With Zig, we create a Quick Prototype of the NuttX Driver for MIPI DSI: [display.zig](display.zig)

https://github.com/lupyuen/pinephone-nuttx/blob/4840d2f1bd42d6bc596040f5417fd8cf8a6dcfeb/display.zig#L62-L167

This MIPI DSI Interface is compatible with Zephyr MIPI DSI...

-   [zephyr/drivers/mipi_dsi.h](https://github.com/zephyrproject-rtos/zephyr/blob/main/include/zephyr/drivers/mipi_dsi.h)

_Why Zig for the MIPI DSI Driver?_

We're doing Quick Prototyping, so it's great to have Zig catch any Runtime Problems caused by our Bad Coding. (Underflow / Overflow / Array Out Of Bounds)

And yet Zig is so similar to C that we can test the Zig Driver with the rest of the C code.

Also `comptime` Compile-Time Expressions in Zig will be helpful when we initialise the ST7703 LCD Controller. [(See this)](https://lupyuen.github.io/articles/dsi#initialise-lcd-controller)

## Compose MIPI DSI Long Packet in Zig

To initialise PinePhone's ST7703 LCD Controller, our PinePhone Display Driver for NuttX shall send MIPI DSI Long Packets to ST7703...

-   ["Long Packet for MIPI DSI"](https://lupyuen.github.io/articles/dsi#long-packet-for-mipi-dsi)

This is how our Zig Driver composes a MIPI DSI Long Packet...

https://github.com/lupyuen/pinephone-nuttx/blob/1262f46622dc07442cf2aa59a4bbc57871308ed1/display.zig#L140-L204

## Compose MIPI DSI Short Packet in Zig

For 1 or 2 bytes of data, our PinePhone Display Driver shall send MIPI DSI Short Packets (instead of Long Packets)...

-   ["Short Packet for MIPI DSI"](https://lupyuen.github.io/articles/dsi#appendix-short-packet-for-mipi-dsi)

This is how our Zig Driver composes a MIPI DSI Short Packet...

https://github.com/lupyuen/pinephone-nuttx/blob/1262f46622dc07442cf2aa59a4bbc57871308ed1/display.zig#L206-L261

## Compute Error Correction Code in Zig

In our PinePhone Display Driver for NuttX, this is how we compute the Error Correction Code for a MIPI DSI Packet...

https://github.com/lupyuen/pinephone-nuttx/blob/1262f46622dc07442cf2aa59a4bbc57871308ed1/display.zig#L263-L304

The Error Correction Code is the last byte of the 4-byte Packet Header for Long Packets and Short Packets.

## Compute Cyclic Redundancy Check in Zig

This is how our PinePhone Display Driver computes the 16-bit Cyclic Redundancy Check (CCITT) in Zig...

https://github.com/lupyuen/pinephone-nuttx/blob/1262f46622dc07442cf2aa59a4bbc57871308ed1/display.zig#L306-L366

The Cyclic Redundancy Check is the 2-byte Packet Footer for Long Packets.

## Test PinePhone MIPI DSI Driver with QEMU

The above Zig Code for composing Long Packets and Short Packets was tested in QEMU for Arm64 with GIC Version 2...

```bash
## TODO: Install Build Prerequisites
## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Create NuttX Directory
mkdir nuttx
cd nuttx

## Download NuttX OS for QEMU with GIC Version 2
git clone \
    --recursive \
    --branch gicv2 \
    https://github.com/lupyuen/incubator-nuttx \
    nuttx

## Download NuttX Apps for QEMU
git clone \
    --recursive \
    --branch arm64 \
    https://github.com/lupyuen/incubator-nuttx-apps \
    apps

## We'll build NuttX inside nuttx/nuttx
cd nuttx

## Configure NuttX for Single Core
./tools/configure.sh -l qemu-a53:nsh

## Build NuttX
make

## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

Follow these steps to compile our Zig App and link into NuttX...

-   ["Zig on PinePhone"](https://github.com/lupyuen/pinephone-nuttx#zig-on-pinephone)

Start NuttX on QEMU Arm64...

Here's the NuttX Test Log for our Zig App on QEMU Arm64...

```text
NuttShell (NSH) NuttX-11.0.0-RC2
nsh> uname -a
NuttX 11.0.0-RC2 c938291 Oct  7 2022 16:54:31 arm64 qemu-a53

nsh> null
HELLO ZIG ON PINEPHONE!
Testing Compose Short Packet (Without Parameter)...
composeShortPacket: channel=0, cmd=0x5, len=1
Result:
05 11 00 36 
Testing Compose Short Packet (With Parameter)...
composeShortPacket: channel=0, cmd=0x15, len=2
Result:
15 bc 4e 35 
Testing Compose Long Packet...
composeLongPacket: channel=0, cmd=0x39, len=64
Result:
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
```

## Test Case for PinePhone MIPI DSI Driver

This is how we write a Test Case for the PinePhone MIPI DSI Driver on NuttX...

https://github.com/lupyuen/pinephone-nuttx/blob/aaf0ed0fb3e8ada663fe9c64f16ea9cb1e3235ed/display.zig#L593-L639

The above Test Case shows this output on QEMU Arm64...

```text
Testing Compose Long Packet...
composeLongPacket: channel=0, cmd=0x39, len=64
Result:
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
```

## Initialise ST7703 LCD Controller in Zig

PinePhone's ST7703 LCD Controller needs to be initialised with these 20 Commands...

-   ["Initialise LCD Controller"](https://lupyuen.github.io/articles/dsi#initialise-lcd-controller)

This is how we send the 20 Commands with our NuttX Driver in Zig, as DCS Short Writes and DCS Long Writes...

https://github.com/lupyuen/pinephone-nuttx/blob/40098cd9ea37ab5e0192b2dc006a98630fa6a7e8/display.zig#L62-L429

To send a command, `writeDcs` executes a DCS Short Write or DCS Long Write, depending on the length of the command...

https://github.com/lupyuen/pinephone-nuttx/blob/40098cd9ea37ab5e0192b2dc006a98630fa6a7e8/display.zig#L431-L453

## Test Zig Display Driver for PinePhone

To test our Zig Display Driver with NuttX on PinePhone, we'll run this p-boot Display Code...

-   [p-boot Display Code](https://gist.github.com/lupyuen/ee3adf76e76881609845d0ab0f768a95)

Here are the steps to download and run the NuttX Binary Image on PinePhone...

1.  Prepare a microSD Card with PinePhone Jumpdrive...

[PinePhone Jumpdrive microSD](https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive)

1.  Download the compressed NuttX Binary Image...

[Image.gz](https://github.com/lupyuen/pinephone-nuttx/releases/download/v1.1.0/Image.gz)

1.  Copy the compressed NuttX Binary Image to Jumpdrive microSD...

```bash
    ## Copy compressed NuttX Binary Image to Jumpdrive microSD.
    ## How to create Jumpdrive microSD: https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive
    ## TODO: Change the microSD Path
    cp Image.gz "/Volumes/NO NAME"
    ```

1.  To access the UART Port on PinePhone, we'll connect this USB Serial Debug Cable (at 115.2 kbps)...

[PinePhone Serial Debug Cable](https://wiki.pine64.org/index.php/PinePhone#Serial_console)

1.  Insert the Jumpdrive microSD into PinePhone and power up

1.  At the NuttX Shell, enter `hello`

We should see...

```text
HELLO NUTTX ON PINEPHONE!
...
Shell (NSH) NuttX-11.0.0-RC2
nsh> hello
...
writeDcs: len=4
b9 f1 12 83 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c b9 f1 12 83 
84 5d 
modifyreg32: addr=0x300, val=0x2c000439
modifyreg32: addr=0x304, val=0x8312f1b9
modifyreg32: addr=0x308, val=0x00005d84
modifyreg32: addr=0x200, val=0x00000009
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
...
```

[(Source)](https://github.com/lupyuen/pinephone-nuttx#testing-nuttx-zig-driver-for-mipi-dsi-on-pinephone)

Our NuttX Zig Display Driver powers on the PinePhone Display and works exactly like the C Driver! 🎉

If we prefer to build the NuttX Binary Image ourselves, here are the steps to download the following Source Files and build them...

```text
nuttx
├── apps (NuttX Apps for PinePhone including Display Engine)
│   ├── Application.mk
│   ├── DISCLAIMER
│   ├── Directory.mk
...
├── nuttx (NuttX OS for PinePhone)
│   ├── AUTHORS
│   ├── CONTRIBUTING.md
│   ├── DISCLAIMER
...
├── p-boot (Modified p-boot Display Code)
│   ├── HACKING
│   ├── LICENSE
│   ├── NEWS
...
├── pinephone-nuttx (Zig Display Driver for PinePhone)
│   ├── LICENSE
│   ├── README.md
│   ├── display.o
│   └── display.zig
...
└── test_display.c (Test Zig Display Driver)
```

1.  Create the NuttX Directory...

```bash
    mkdir nuttx
    cd nuttx
    ```

1.  Download `test-display.c` into the `nuttx` folder...

[`test-display.c`](https://gist.github.com/lupyuen/ee3adf76e76881609845d0ab0f768a95)

1.  Download the Modified p-boot Display Code `p-boot.4.zip` from...

[pinephone-nuttx/releases/tag/pboot4](https://github.com/lupyuen/pinephone-nuttx/releases/tag/pboot4)

Extract into the `nuttx` folder and rename as `p-boot`

1.  Download and build NuttX for PinePhone inside the `nuttx` folder...

```bash
    ## TODO: Install Build Prerequisites
    ## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Download NuttX OS for PinePhone
    git clone \
        --recursive \
        --branch pinephone \
        https://github.com/lupyuen/incubator-nuttx \
        nuttx

## Download NuttX Apps for PinePhone including Display Engine
    git clone \
        --recursive \
        --branch de \
        https://github.com/lupyuen/incubator-nuttx-apps \
        apps

## We'll build NuttX inside nuttx/nuttx
    cd nuttx

## Configure NuttX for Single Core
    ./tools/configure.sh -l qemu-a53:nsh

## Build NuttX. Ignore the Linker Errors
    make
    ```

1.  Follow these steps to compile our Zig App and link into NuttX...

-   ["Zig on PinePhone"](https://github.com/lupyuen/pinephone-nuttx#zig-on-pinephone)

1.  Compress the NuttX Binary Image...

```bash
    cp nuttx.bin Image
    rm -f Image.gz
    gzip Image
    ```

1.  Copy the compressed NuttX Binary Image `Image.gz` to Jumpdrive microSD according to the steps above.

Insert the Jumpdrive microSD into PinePhone and power up.

At the NuttX Shell, enter `hello`

(The steps look messy today, hopefully we'll remove p-boot after we have created our NuttX Display Driver)

_Can our driver render graphics on PinePhone Display?_

Our PinePhone Display Driver isn't complete. It handles MIPI DSI (for initialising ST7703) but doesn't support Allwinner A64's Display Engine (DE) and Timing Controller (TCON), which are needed for rendering graphics.

We'll implement DE and TCON next.

![Mandelbrot Set on PinePhone](https://lupyuen.github.io/images/de-title.jpg)

## Display Engine in Allwinner A64

Let's look inside PinePhone's Allwinner A64 Display Engine ... And render some graphics with Apache NuttX RTOS.

Here's the doc for the Display Engine...

-   [__Allwinner Display Engine 2.0 Specifications__](https://linux-sunxi.org/images/7/7b/Allwinner_DE2.0_Spec_V1.0.pdf)

_Which Display Engine for A64 (sun50iw1): H8, H3, H5 or A83?_

PinePhone's A64 Display Engine is hidden in the Allwinner H3 Docs, because Allwinner A64 is actually a H3 upgraded with 64-bit Cores...

> The A64 is basically an Allwinner H3 with the Cortex-A7 cores replaced with Cortex-A53 cores (ARM64 architecture). They share most of the memory map, clocks, interrupts and also uses the same IP blocks.

[(Source)](https://linux-sunxi.org/A64)

According to the doc, DE Base Address is 0x0100 0000 (Page 24)

Let's look at the DE Mixers...

![A64 Display Engine](https://lupyuen.github.io/images/de-block1a.jpg)

## Display Engine Mixers

_What's a Display Engine Mixer?_

__DE RT-MIXER:__ (Page 87)
> The RT-mixer Core consist of dma, overlay, scaler and blender block. It supports 4 layers overlay in one pipe, and its result can scaler up or down to blender in the next processing.

The Display Engine has 2 Mixers: RT-MIXER0 and RT-MIXER1...

__DE RT-MIXER0__ has 4 Channels (DE Offset 0x10 0000, Page 87)
-   Channel 0 for Video: DMA0, Video Overlay, Video Scaler
-   Channels 1, 2, 3 for UI: DMA1 / 2 / 3, UI Overlays, UI Scalers, UI Blenders
-   4 Overlay Layers per Channel
-   Layer priority is Layer 3 > Layer2 > Layer 1 > Layer 0 (Page 89)
-   Channel 0 is unused (we don't use video right now)
-   Channel 1 has format XRGB 8888
-   Channels 2 and 3 have format ARGB 8888
-   MIXER0 Registers:
    -   GLB at MIXER0 Offset 0x00000 (de_glb_regs)
    -   BLD (Blender) at MIXER0 Offset 0x01000 (de_bld_regs)
    -   OVL_V(CH0) (Video Overlay / Channel 0) at MIXER0 Offset 0x2000 (Unused)
    -   OVL_UI(CH1) (UI Overlay / Channel 1) at MIXER0 Offset 0x3000
    -   OVL_UI(CH2) (UI Overlay / Channel 2) at MIXER0 Offset 0x4000
    -   OVL_UI(CH3) (UI Overlay / Channel 3) at MIXER0 Offset 0x5000
    -   POST_PROC2 at MIXER0 Offset 0xB0000 (de_csc_regs)

![A64 Display Engine MIXER0](https://lupyuen.github.io/images/de-mixer1a.jpg)

__DE RT-MIXER1__ has 2 Channels (DE Offset 0x20 0000, Page 23)
-   Channel 0 for Video: DMA0, Video Overlay, Video Scaler
-   Channel 1 for UI: DMA1, UI Overlay, UI Scaler, UI Blender
-   We don't use MIXER1 right now

RT-MIXER0 and RT-MIXER1 are multiplexed to Timing Controller TCON0.

(TCON0 is connected to ST7703 over MIPI DSI)

So MIXER0 mixes 1 Video Channel with 3 UI Channels over DMA ... And pumps the pixels continuously to ST7703 LCD Controller (via the Timing Controller)

Let's use the 3 UI Channels to render: 1️⃣ Mandelbrot Set 2️⃣ Blue Square 3️⃣ Green Circle

![Mandelbrot Set with UI Overlays on PinePhone](https://lupyuen.github.io/images/de-overlay.jpg)

_Why 2 Mixers in A64 Display Engine?_

Maybe because A64 (or H3) was designed for [OTT Set-Top Boxes](https://linux-sunxi.org/H3) with Picture-In-Picture Overlay Videos?

The 3 UI Overlay Channels would be useful for overlaying a Text UI on top of a Video Channel.

(Is that why Allwinner calls them "Channels"?)

[(Wait... Wasn't Pine64 created thanks to OTT Boxes? 🤔)](https://en.wikipedia.org/wiki/Pine64#:~:text=Pine64%20initially%20operated%20as%20Pine%20Microsystems%20Inc.%20(Fremont%2C%20California)%2C%20founded%20by%20TL%20Lim%2C%20the%20inventor%20of%20the%20PopBox%20and%20Popcorn%20Hour%20series%20of%20media%20players%20sold%20under%20the%20Syabas%20and%20Cloud%20Media%20brands.%5B2%5D)

## Render Colours

Let's render simple colour blocks on the PinePhone Display.

We allocate the Framebuffer: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Init Framebuffer 0:
// Fullscreen 720 x 1440 (4 bytes per RGBA pixel)
static uint32_t fb0[720 * 1440];
int fb0_len = sizeof(fb0) / sizeof(fb0[0]);
```

We fill the Framebuffer with Blue, Green and Red: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Fill with Blue, Green and Red
for (int i = 0; i < fb0_len; i++) {
    // Colours are in ARGB format
    if (i < fb0_len / 4) {
        // Blue for top quarter
        fb0[i] = 0x80000080;
    } else if (i < fb0_len / 2) {
        // Green for next quarter
        fb0[i] = 0x80008000;
    } else {
        // Red for lower half
        fb0[i] = 0x80800000;
    }
}
```

We allocate 3 UI Channels: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Allocate 3 UI Channels
static struct display disp;
memset(&disp, 0, sizeof(disp));
struct display *d = &disp;
```

We init the 3 Channels and render them: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Init UI Channel 1: (Base Channel)
// Fullscreen 720 x 1440
d->planes[0].fb_start = (uintptr_t) fb0;  // Framebuffer Address
d->planes[0].fb_pitch = 720 * 4;  // Framebuffer Pitch
d->planes[0].src_w    = 720;   // Source Width
d->planes[0].src_h    = 1440;  // Source Height
d->planes[0].dst_w    = 720;   // Dest Width
d->planes[0].dst_h    = 1440;  // Dest Height

// Init UI Channel 2: (First Overlay)
// Square 600 x 600
d->planes[1].fb_start = 0;  // To Disable Channel

// Init UI Channel 3: (Second Overlay)
// Fullscreen 720 x 1440 with Alpha Blending
d->planes[2].fb_start = 0;  // To Disable Channel

// Render the UI Channels
display_commit(d);
```

`display_commit` is defined in the p-boot Display Code: [display.c](https://megous.com/git/p-boot/tree/src/display.c#n2017)

We should see these Blue, Green and Red Blocks...

![Blue, Green, Red Blocks on PinePhone](https://lupyuen.github.io/images/de-rgb.jpg)

(Why the black lines?)

Channels 2 and 3 are disabled for now. We'll use them to render UI Overlays later.

## Render Mandelbrot Set

Let's render something more interesting... Mandelbrot Set: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Fill with Mandelbrot Set
for (int y = 0; y < 1440; y++) {
    for (int x = 0; x < 720; x++) {
        // Convert Pixel Coordinates to a Complex Number
        float cx = x_start + (y / 1440.0) * (x_end - x_start);
        float cy = y_start + (x / 720.0)  * (y_end - y_start);

// Compute Manelbrot Set
        int m = mandelbrot(cx, cy);

// Color depends on the number of iterations
        uint8_t hue = 255.0 * m / MAX_ITER;
        uint8_t saturation = 255;
        uint8_t value = (m < MAX_ITER) ? 255 : 0;

// Convert Hue / Saturation / Value to RGB
        uint32_t rgb = hsvToRgb(hue, saturation, value);

// Set the Pixel Colour (ARGB Format)
        int p = (y * 720) + x;
        assert(p < fb0_len);
        fb0[p] = 0x80000000 | rgb;
    }
}
```

`mandelbrot` and `hsvToRgb` are defined here: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c#L330-L426)

We should see this Mandelbrot Set...

![Mandelbrot Set on PinePhone](https://lupyuen.github.io/images/de-title.jpg)

## Animate Madelbrot Set

Now we animate the Mandelbrot Set: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Omitted: Init UI Channels 1, 2 and 3
...
// Render the UI Channels
display_commit(d);

// Animate the Mandelbrot Set forever...
for (;;) {
    // Fill with Mandelbrot Set
    for (int y = 0; y < 1440; y++) {
        for (int x = 0; x < 720; x++) {
            // Convert Pixel Coordinates to a Complex Number
            float cx = x_start + (y / 1440.0) * (x_end - x_start);
            float cy = y_start + (x / 720.0)  * (y_end - y_start);

// Compute Manelbrot Set
            int m = mandelbrot(cx, cy);

// Color depends on the number of iterations
            uint8_t hue = 255.0 * m / MAX_ITER;
            uint8_t saturation = 255;
            uint8_t value = (m < MAX_ITER) ? 255 : 0;

// Convert Hue / Saturation / Value to RGB
            uint32_t rgb = hsvToRgb(hue, saturation, value);

// Set the Pixel Colour (ARGB Format)
            int p = (y * 720) + x;
            assert(p < fb0_len);
            fb0[p] = 0x80000000 | rgb;
        }
    }
    // Zoom in to (-1.4, 0)
    float x_dest = -1.4;
    float y_dest = 0;
    x_start += (x_dest - x_start) * 0.05;
    x_end   -= (x_end  - x_dest)  * 0.05;
    y_start += (y_dest - y_start) * 0.05;
    y_end   -= (y_end  - y_dest)  * 0.05;
}
```

We should see the Animated Mandelbrot Set...

-   [Demo Video on YouTube](https://youtu.be/toC9iiPRwRI)

_Don't we need to call `display_commit` after every frame?_

Nope, remember that the Display Engine reads our Framebuffer directly via DMA.

So any updates to the Framebuffer will be pushed to the display instantly.

## Render Square Overlay

This is how we render a Blue Square as an Overlay on UI Channel 2: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Init Framebuffer 1:
// Square 600 x 600 (4 bytes per RGBA pixel)
static uint32_t fb1[600 * 600];
int fb1_len = sizeof(fb1) / sizeof(fb1[0]);

// Fill with Blue
for (int i = 0; i < fb1_len; i++) {
    // Colours are in ARGB format
    fb1[i] = 0x80000080;
}

// Init UI Channel 2: (First Overlay)
// Square 600 x 600
d->planes[1].fb_start = (uintptr_t) fb1;  // Framebuffer Address
d->planes[1].fb_pitch = 600 * 4;  // Framebuffer Pitch
d->planes[1].src_w    = 600;  // Source Width
d->planes[1].src_h    = 600;  // Source Height
d->planes[1].dst_w    = 600;  // Dest Width
d->planes[1].dst_h    = 600;  // Dest Height
d->planes[1].dst_x    = 52;   // Dest X
d->planes[1].dst_y    = 52;   // Dest Y
```

## Render Circle Overlay

This is how we render a Green Circle as an Overlay on UI Channel 3: [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

```c
// Init Framebuffer 2:
// Fullscreen 720 x 1440 (4 bytes per RGBA pixel)
static uint32_t fb2[720 * 1440];
int fb2_len = sizeof(fb2) / sizeof(fb2[0]);

// Fill with Green Circle
for (int y = 0; y < 1440; y++) {
    for (int x = 0; x < 720; x++) {
        // Get pixel index
        int p = (y * 720) + x;
        assert(p < fb2_len);

// Shift coordinates so that centre of screen is (0,0)
        int x_shift = x - 360;
        int y_shift = y - 720;

// If x^2 + y^2 < radius^2, set the pixel to Green
        if (x_shift*x_shift + y_shift*y_shift < 360*360) {
            fb2[p] = 0x80008000;  // Green in ARGB Format
        } else {  // Otherwise set to Black
            fb2[p] = 0x00000000;  // Black in ARGB Format
        }
    }
}

// Init UI Channel 3: (Second Overlay)
// Fullscreen 720 x 1440 with Alpha Blending
d->planes[2].fb_start = (uintptr_t) fb2;  // Framebuffer Address
d->planes[2].fb_pitch = 720 * 4;  // Framebuffer Pitch
d->planes[2].src_w    = 720;   // Source Width
d->planes[2].src_h    = 1440;  // Source Height
d->planes[2].dst_w    = 720;   // Dest Width
d->planes[2].dst_h    = 1440;  // Dest Height
d->planes[2].dst_x    = 0;     // Dest X
d->planes[2].dst_y    = 0;     // Dest Y
d->planes[2].alpha    = 128;   // Dest Alpha
```

Note that we set the Destination Alpha. So the green will appear nearly invisible.

We should see the Animated Mandelbrot Set, with Blue Square and Green Circle as Overlays...

![Mandelbrot Set with Blue Square and Green Circle on PinePhone](https://lupyuen.github.io/images/de-overlay.jpg)

(Why the missing horizontal lines in the Blue Square and Green Circle?)

## Test PinePhone Display Engine

To test the A64 Display Engine with NuttX on PinePhone, we'll run this p-boot Display Code...

-   [display.c](https://megous.com/git/p-boot/tree/src/display.c#n2017)

With our Test App...

-   [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c)

Here are the steps to download and run the NuttX Binary Image on PinePhone...

1.  Prepare a microSD Card with PinePhone Jumpdrive...

[PinePhone Jumpdrive microSD](https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive)

1.  Download the compressed NuttX Binary Image...

[Image.gz](https://github.com/lupyuen/pinephone-nuttx/releases/download/v1.1.0/Image.gz)

1.  Copy the compressed NuttX Binary Image to Jumpdrive microSD...

1.  To access the UART Port on PinePhone, we'll connect this USB Serial Debug Cable (at 115.2 kbps)...

[PinePhone Serial Debug Cable](https://wiki.pine64.org/index.php/PinePhone#Serial_console)

1.  Insert the Jumpdrive microSD into PinePhone and power up

1.  At the NuttX Shell, enter `hello`

We should see the Animated Mandelbrot Set, with Blue Square and Green Circle as Overlays...

![Mandelbrot Set with Blue Square and Green Circle on PinePhone](https://lupyuen.github.io/images/de-overlay.jpg)

(Why the missing horizontal lines in the Blue Square and Green Circle?)

If we prefer to build the NuttX Binary Image ourselves, here are the steps to download the following Source Files and build them...

```text
nuttx
├── apps (NuttX Apps for PinePhone including Display Engine Version 2)
│   ├── Application.mk
│   ├── DISCLAIMER
│   ├── Directory.mk
...
├── nuttx (NuttX OS for PinePhone)
│   ├── AUTHORS
│   ├── CONTRIBUTING.md
│   ├── DISCLAIMER
...
├── p-boot (Modified p-boot Display Code)
│   ├── HACKING
│   ├── LICENSE
│   ├── NEWS
...
└── pinephone-nuttx (Zig MIPI DSI Driver for PinePhone)
    ├── LICENSE
    ├── README.md
    ├── display.o
    └── display.zig
```

1.  Create the NuttX Directory...

```bash
    mkdir nuttx
    cd nuttx
    ```

1.  Download the Modified Instrumented p-boot Display Code `p-boot.6.zip` from...

[pinephone-nuttx/releases/tag/pboot6](https://github.com/lupyuen/pinephone-nuttx/releases/tag/pboot6)

Extract into the `nuttx` folder and rename as `p-boot`

1.  Download and build NuttX for PinePhone inside the `nuttx` folder...

```bash
    ## TODO: Install Build Prerequisites
    ## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Download NuttX OS for PinePhone
    git clone \
        --recursive \
        --branch pinephone \
        https://github.com/lupyuen/incubator-nuttx \
        nuttx

## Download NuttX Apps for PinePhone including Display Engine (Version 2)
    git clone \
        --recursive \
        --branch de2 \
        https://github.com/lupyuen/incubator-nuttx-apps \
        apps

## We'll build NuttX inside nuttx/nuttx
    cd nuttx

## Configure NuttX for Single Core
    ./tools/configure.sh -l qemu-a53:nsh

## Build NuttX. Ignore the Linker Errors
    make
    ```

1.  Follow these steps to compile our Zig MIPI DSI Driver and link into NuttX...

-   ["Zig on PinePhone"](https://github.com/lupyuen/pinephone-nuttx#zig-on-pinephone)

1.  Compress the NuttX Binary Image...

```bash
    cp nuttx.bin Image
    rm -f Image.gz
    gzip Image
    ```

1.  Copy the compressed NuttX Binary Image `Image.gz` to Jumpdrive microSD according to the steps above.

Insert the Jumpdrive microSD into PinePhone and power up.

At the NuttX Shell, enter `hello`

(The steps look messy today, hopefully we'll remove p-boot after we have created our NuttX Display Driver)

## Display Engine Usage

Based on the log captured from our instrumented [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de2/examples/hello/test_display.c), we have identified the steps to render 3 UI Channels (1 to 3) with the Display Engine [(`display_commit`)](https://megous.com/git/p-boot/tree/src/display.c#n2017)

This is how we'll create a NuttX Driver for PinePhone's A64 Display Engine that implements Display Rendering...

1.  Configure Blender...
    -   BLD BkColor (BLD_BK_COLOR Offset 0x88): BLD background color register
    -   BLD Premultiply (BLD_PREMUL_CTL Offset 0x84): BLD pre-multiply control register

```text
    Configure Blender
    BLD BkColor:     0x110 1088 = 0xff000000
    BLD Premultiply: 0x110 1084 = 0x0
    ```

1.  For Channels 1 to 3...

1.  If Channel is unused, disable Overlay, Pipe and Scaler. Skip to next Channel

-   UI Config Attr (OVL_UI_ATTCTL @ OVL_UI Offset 0x00): OVL_UI attribute control register
        -   Mixer (??? @ 0x113 0000 + 0x10000 * Channel)

```text
        Channel 2: Disable Overlay and Pipe
        UI Config Attr: 0x110 4000 = 0x0

Channel 3: Disable Overlay and Pipe
        UI Config Attr: 0x110 5000 = 0x0

Channel 2: Disable Scaler
        Mixer: 0x115 0000 = 0x0

Channel 3: Disable Scaler
        Mixer: 0x116 0000 = 0x0
        ```

1.  Channel 1 has format XRGB 8888, Channel 2 and 3 have format ARGB 8888

1.  Set Overlay (Assume Layer = 0)
        -   UI Config Attr (OVL_UI_ATTCTL @ OVL_UI Offset 0x00): OVL_UI attribute control register
        -   UI Config Top LAddr (OVL_UI_TOP_LADD @ OVL_UI Offset 0x10): OVL_UI top field memory block low address register
        -   UI Config Pitch (OVL_UI_PITCH @ OVL_UI Offset 0x0C): OVL_UI memory pitch register
        -   UI Config Size (OVL_UI_MBSIZE @ OVL_UI Offset 0x04): OVL_UI memory block size register
        -   UI Overlay Size (OVL_UI_SIZE @ OVL_UI Offset 0x88): OVL_UI overlay window size register
        -   IO Config Coord (OVL_UI_COOR @ OVL_UI Offset 0x08): OVL_UI memory block coordinate register

```text
        Channel 1: Set Overlay (fb0 is 720 x 1440)
        UI Config Attr:      0x110 3000 = 0xff00 0405
        UI Config Top LAddr: 0x110 3010 = 0x4064 a6ac (Address of fb0)
        UI Config Pitch:     0x110 300c = 0xb40 (720 * 4)
        UI Config Size:      0x110 3004 = 0x59f 02cf (1439 << 16 + 719)
        UI Overlay Size:     0x110 3088 = 0x59f 02cf (1439 << 16 + 719)
        IO Config Coord:     0x110 3008 = 0x0

Channel 2: Set Overlay (fb1 is 600 x 600)
        UI Config Attr:      0x110 4000 = 0xff00 0005
        UI Config Top LAddr: 0x110 4010 = 0x404e adac (Address of fb1)
        UI Config Pitch:     0x110 400c = 0x960 (600 * 4)
        UI Config Size:      0x110 4004 = 0x257 0257 (599 << 16 + 599)
        UI Overlay Size:     0x110 4088 = 0x257 0257 (599 << 16 + 599)
        IO Config Coord:     0x110 4008 = 0x0

Channel 3: Set Overlay (fb2 is 720 x 1440)
        UI Config Attr:      0x110 5000 = 0x7f00 0005
        UI Config Top LAddr: 0x110 5010 = 0x400f 65ac (Address of fb2)
        UI Config Pitch:     0x110 500c = 0xb40 (720 * 4)
        UI Config Size:      0x110 5004 = 0x59f 02cf (1439 << 16 + 719)
        UI Overlay Size:     0x110 5088 = 0x59f 02cf (1439 << 16 + 719)
        IO Config Coord:     0x110 5008 = 0x0
        ```

Note that UI Config Size and UI Overlay Size are `(height-1) << 16 + (width-1)`

1.  For Channel 1: Set Blender Output
        -   BLD Output Size (BLD_SIZE @ BLD Offset 0x08C): BLD output size setting register
        -   GLB Size (GLB_SIZE @ GLB Offset 0x00C): Global size register

```text
        Channel 1: Set Blender Output
        BLD Output Size: 0x110 108c = 0x59f 02cf (1439 * 16 + 719)
        GLB Size:        0x110 000c = 0x59f 02cf (1439 * 16 + 719)
        ```

1.  Set Blender Input Pipe (N = Pipe Number, from 0 to 2 for Channels 1 to 3)
        -   BLD Pipe InSize (BLD_CH_ISIZE @ BLD Offset 0x008 + N*0x14): BLD input memory size register(N=0,1,2,3,4)
        -   BLD Pipe FColor (BLD_FILL_COLOR @ BLD Offset 0x004 + N*0x14): BLD fill color register(N=0,1,2,3,4)
        -   BLD Pipe Offset (BLD_CH_OFFSET @ BLD Offset 0x00C + N*0x14): BLD input memory offset register(N=0,1,2,3,4)
        -   BLD Pipe Mode (BLD_CTL @ BLD Offset 0x090 – 0x09C): BLD control register

(Should `N*0x14` be `N*0x10` instead?)

```text
        Channel 1: Set Blender Input Pipe 0 (fb0 is 720 x 1440)
        BLD Pipe InSize: 0x110 1008 = 0x59f 02cf (1439 * 16 + 719)
        BLD Pipe FColor: 0x110 1004 = 0xff00 0000
        BLD Pipe Offset: 0x110 100c = 0x0
        BLD Pipe Mode:   0x110 1090 = 0x301 0301

Channel 2: Set Blender Input Pipe 1 (fb1 is 600 x 600)
        BLD Pipe InSize: 0x110 1018 = 0x257 0257 (599 << 16 + 599)
        BLD Pipe FColor: 0x110 1014 = 0xff00 0000
        BLD Pipe Offset: 0x110 101c = 0x34 0034
        BLD Pipe Mode:   0x110 1094 = 0x301 0301

Channel 3: Set Blender Input Pipe 2 (fb2 is 720 x 1440)
        BLD Pipe InSize: 0x110 1028 = 0x59f 02cf (1439 * 16 + 719)
        BLD Pipe FColor: 0x110 1024 = 0xff00 0000
        BLD Pipe Offset: 0x110 102c = 0x0
        BLD Pipe Mode:   0x110 1098 = 0x301 0301
        ```

Note that BLD Pipe InSize is `(height-1) << 16 + (width-1)`

1.  Disable Scaler (assuming we're not using Scaler)

```text
        Channel 1: Disable Scaler
        Mixer: 0x114 0000 = 0x0

Channel 2: Disable Scaler
        Mixer: 0x115 0000 = 0x0

Channel 3: Disable Scaler
        Mixer: 0x116 0000 = 0x0
        ```

1.  Set BLD Route and BLD FColor Control
    -   BLD Route (BLD_CH_RTCTL @ BLD Offset 0x080): BLD routing control register
    -   BLD FColor Control (BLD_FILLCOLOR_CTL @ BLD Offset 0x000): BLD fill color control register

```text
    Set BLD Route and BLD FColor Control
    BLD Route:          0x110 1080 = 0x321
    BLD FColor Control: 0x110 1000 = 0x701
    ```

1.  Apply Settings: GLB DBuff
    -   GLB DBuff (GLB_DBUFFER @ GLB Offset 0x008): Global double buffer control register

```text
    Apply Settings
    GLB DBuff: 0x110 0008 = 0x1
    ```

[(See the Complete Log)](https://github.com/lupyuen/pinephone-nuttx#testing-p-boot-display-engine-on-pinephone)

(See Memory Mapping List and Register List at Page 90)

## Other Display Engine Features

We won't use these Display Engine Features today...

__DE RT-WB:__ (Page 116)
> The Real-time write-back controller (RT-WB) provides data capture function for display engine. It captures data from RT-mixer module, performs the image resizing function, and then write-back to SDRAM.

(For screen capture?)

__DE VSU:__ (Page 128)
> The Video Scaler (VS) provides YUV format image resizing function for display engine. It receives data from overlay module, performs the image resizing function, and outputs to video post-processing modules.

__DE Rotation:__ (Page 137)
> There are several types of rotation: clockwise 0/90/180/270 degree Rotation and H-Flip/V-Flip. Operation of Copy is the same as a 0 degree rotation.

## Timing Controller in Allwinner A64

See this...

-   ["Timing Controller (TCON0)"](https://lupyuen.github.io/articles/de#appendix-timing-controller-tcon0)

![Blue, Green, Red Blocks on PinePhone](https://lupyuen.github.io/images/de2-test1.jpg)

## Zig Driver for PinePhone Display Engine

We have created a Zig Driver for PinePhone's Allwinner A64 Display Engine that will render graphics...

-   ["NuttX RTOS for PinePhone: Render Graphics in Zig"](https://lupyuen.github.io/articles/de2)

-   ["Rendering PinePhone's Display (DE and TCON0)"](https://lupyuen.github.io/articles/de)

To test the rendering of graphics, let's run this Zig App on NuttX for PinePhone...

-   [render.zig](render.zig)

-   [display.zig](display.zig)

Follow the instructions in the next section to download and build the NuttX Source Code for PinePhone.

In NuttX, enable the Null Example App: `make menuconfig`, select "Application Configuration" > "Examples" > "Null Example"

Compile the Zig App (based on the GCC Compiler Options, see below)...

```bash
#  Change "$HOME/nuttx" for your NuttX Project Directory
cd $HOME/nuttx

#  Download the Zig App
git clone --recursive https://github.com/lupyuen/pinephone-nuttx
cd pinephone-nuttx

#  Copy the compiled app to NuttX and overwrite `null.o`
#  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
cp render.o \
  $HOME/nuttx/apps/examples/null/*null.o

#  Build NuttX to link the Zig Object from `null.o`
#  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
cd $HOME/nuttx/nuttx
make
```

To run the Zig App...

```text
## Render colour bars (pic above)
hello 1

## Render colour bars with overlays (pic below)
hello 3
```

_How did we get the Zig Compiler options `-target`, `-mcpu`, `-isystem` and `-I`?_

`make --trace` shows these GCC Compiler Options when building Nuttx for PinePhone...

We copied and modified these GCC Compiler Options for Zig.

_What about `-D__NuttX__`?_

The Zig Compiler won't let us specify C Macros at the Command Line, so we defined the macro `__NuttX__` in our Zig App...

https://github.com/lupyuen/pinephone-nuttx/blob/6ba90edb155a0132400ce66752eea7612c0d022e/render.zig#L32-L53

![Blue, Green, Red Blocks with Overlays](https://lupyuen.github.io/images/de2-test3.jpg)

## Test Zig Driver for PinePhone Display Engine

To test the A64 Display Engine with NuttX on PinePhone, we'll run our NuttX Test App...

-   [test_display.c](https://github.com/lupyuen/incubator-nuttx-apps/blob/de3/examples/hello/test_display.c)

Which calls our Zig Display Driver for PinePhone...

-   [render.zig](render.zig)

-   [display.zig](display.zig)

Here are the steps to download and run the NuttX Binary Image on PinePhone...

1.  Prepare a microSD Card with PinePhone Jumpdrive...

[PinePhone Jumpdrive microSD](https://lupyuen.github.io/articles/uboot#pinephone-jumpdrive)

1.  Download the compressed NuttX Binary Image...

[Image.gz](https://github.com/lupyuen/pinephone-nuttx/releases/download/v1.1.1/Image.gz)

1.  Copy the compressed NuttX Binary Image to Jumpdrive microSD...

1.  To access the UART Port on PinePhone, we'll connect this USB Serial Debug Cable (at 115.2 kbps)...

[PinePhone Serial Debug Cable](https://wiki.pine64.org/index.php/PinePhone#Serial_console)

1.  Insert the Jumpdrive microSD into PinePhone and power up

1.  At the NuttX Shell, enter `hello 1` to render the Blue, Green and Red colour bars

[(See the Complete Log)](https://gist.github.com/lupyuen/9824d0cece10bfdaa13da3660c6d9cf5)

1.  Or enter `hello 3` to render the same colour bars with Blue Square and Green Circle as Overlays

[(See the Complete Log)](https://gist.github.com/lupyuen/d8d6710ab2ed16765816157cb97e54e7)

If we prefer to build the NuttX Binary Image ourselves, here are the steps to download the following Source Files and build them...

```text
nuttx
├── apps (NuttX Apps for PinePhone including Display Engine Version 2)
│   ├── Application.mk
│   ├── DISCLAIMER
│   ├── Directory.mk
...
├── nuttx (NuttX OS for PinePhone)
│   ├── AUTHORS
│   ├── CONTRIBUTING.md
│   ├── DISCLAIMER
...
├── p-boot (Modified p-boot Display Code)
│   ├── HACKING
│   ├── LICENSE
│   ├── NEWS
...
└── pinephone-nuttx (Zig MIPI DSI / Display Engine Driver for PinePhone)
    ├── LICENSE
    ├── README.md
    ├── display.zig
    └── render.zig
```

1.  Create the NuttX Directory...

```bash
    mkdir nuttx
    cd nuttx
    ```

1.  Download the Modified p-boot Display Code `p-boot.11.zip` from...

[pinephone-nuttx/releases/tag/pboot11](https://github.com/lupyuen/pinephone-nuttx/releases/tag/pboot11)

Extract into the `nuttx` folder and rename as `p-boot`

1.  Download and build NuttX for PinePhone inside the `nuttx` folder...

```bash
    ## TODO: Install Build Prerequisites
    ## https://lupyuen.github.io/articles/uboot#install-prerequisites

## Download NuttX OS for PinePhone
    git clone \
        --recursive \
        --branch pinephone \
        https://github.com/lupyuen/incubator-nuttx \
        nuttx

## Download NuttX Apps for PinePhone including Display Engine (Version 3)
    git clone \
        --recursive \
        --branch de3 \
        https://github.com/lupyuen/incubator-nuttx-apps \
        apps

## We'll build NuttX inside nuttx/nuttx
    cd nuttx

## Configure NuttX for Single Core
    ./tools/configure.sh -l qemu-a53:nsh

## Build NuttX. Ignore the Linker Errors
    make
    ```

1.  Follow these steps to compile our Zig MIPI DSI Driver and link into NuttX...

["Zig Driver for PinePhone Display Engine"](https://github.com/lupyuen/pinephone-nuttx#zig-driver-for-pinephone-display-engine)

1.  Compress the NuttX Binary Image...

```bash
    cp nuttx.bin Image
    rm -f Image.gz
    gzip Image
    ```

1.  Copy the compressed NuttX Binary Image `Image.gz` to Jumpdrive microSD according to the steps above.

Insert the Jumpdrive microSD into PinePhone and power up.

At the NuttX Shell, enter `hello 1` or `hello 3`

(The steps look messy today, hopefully we'll remove p-boot after we have created our NuttX Display Driver)

## Complete PinePhone Display Driver in Zig

We have completed the entire PinePhone Display Driver in Zig!

https://github.com/lupyuen/pinephone-nuttx/blob/432c15a55d97fd044f291aba292b1c4efb431f41/render.zig#L176-L226

Here are the Zig Modules...

-   [`render.zig`](render.zig): Allwinner A64 Display Engine (DE)

-   [`display.zig`](display.zig): Allwinner A64 MIPI Display Serial Interface (DSI)

-   [`dphy.zig`](dphy.zig): Allwinner A64 MIPI Display Physical Layer (DPHY)

-   [`tcon.zig`](tcon.zig): Allwinner A64 Timing Controller (TCON0)

-   [`backlight.zig`](backlight.zig): PinePhone Display Backlight

-   [`pmic.zig`](pmic.zig): PinePhone Power Management Integrated Circuit

-   [`panel.zig`](panel.zig): PinePhone LCD Panel

This is the detailed output of the Zig Driver, with Register Addresses and Values...

-   ["Testing Zig Driver on PinePhone"](https://github.com/lupyuen/pinephone-nuttx#testing-zig-backlight-driver-on-pinephone)

We'll merge these modules to NuttX Mainline as a NuttX Framebuffer Driver.

We created these modules by reverse-engineering the log generated by the [p-boot Display Code](https://gist.github.com/lupyuen/c12f64cf03d3a81e9c69f9fef49d9b70).

## Add MIPI DSI to NuttX Kernel

We're adding the MIPI DSI Driver to the NuttX Kernel...

-   [mipi_dsi.c](https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/mipi_dsi.c): Compose MIPI DSI Packets (Long, Short, Short with Parameter)

-   [a64_mipi_dsi.c](https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/a64_mipi_dsi.c): MIPI Display Serial Interface (DSI) for Allwinner A64

-   [a64_mipi_dphy.c](https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/a64_mipi_dphy.c): MIPI Display Physical Layer (D-PHY) for Allwinner A64

We created the above NuttX Source Files (in C) by converting our Zig MIPI DSI Driver to C...

-   [display.zig](display.zig): Zig Driver for MIPI DSI

-   [dphy.zig](dphy.zig): Zig Driver for MIPI D-PHY

That we Reverse-Engineered from the logs that we captured from PinePhone p-boot...

-   ["Understanding PinePhone's Display (MIPI DSI)"](https://lupyuen.github.io/articles/dsi)

-   ["NuttX RTOS for PinePhone: Display Driver in Zig"](https://lupyuen.github.io/articles/dsi2)

-   ["Rendering PinePhone's Display (DE and TCON0)"](https://lupyuen.github.io/articles/de)

-   ["NuttX RTOS for PinePhone: Render Graphics in Zig"](https://lupyuen.github.io/articles/de2)

_Was it difficult to convert Zig to C?_

Not at all!

Here's the Zig code for our MIPI DSI Driver...

https://github.com/lupyuen/pinephone-nuttx/blob/3d33e5a49a5a3857c39fe8aa79af60902a70088e/display.zig#L115-L170

And here's the converted C code for NuttX: [mipi_dsi.c](https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/mipi_dsi.c#L392-L484)

```c
ssize_t mipi_dsi_short_packet(FAR uint8_t *pktbuf,
                              size_t pktlen,
                              uint8_t channel,
                              enum mipi_dsi_e cmd,
                              FAR const uint8_t *txbuf,
                              size_t txlen)
{
  /* Data Identifier (DI) (1 byte):
   * Virtual Channel Identifier (Bits 6 to 7)
   * Data Type (Bits 0 to 5) */
  const uint8_t vc = channel;
  const uint8_t dt = cmd;
  const uint8_t di = (vc << 6) |
                     dt;

/* Data (2 bytes): Fill with 0 if Second Byte is missing */
  const uint8_t data[2] =
    {
      txbuf[0],                     /* First Byte */
      (txlen == 2) ? txbuf[1] : 0,  /* Second Byte */
    };

/* Data Identifier + Data (3 bytes):
   * For computing Error Correction Code (ECC) */
  const uint8_t di_data[3] =
    {
      di,
      data[0],
      data[1]
    };

/* Compute ECC for Data Identifier + Word Count */
  const uint8_t ecc = compute_ecc(di_data,
                                  sizeof(di_data));

/* Packet Header (4 bytes):
   * Data Identifier + Data + Error Correction Code */
  const uint8_t header[4] =
    {
      di_data[0],
      di_data[1],
      di_data[2],
      ecc
    };

/* Packet Length is Packet Header Size (4 bytes) */
  const size_t len = sizeof(header);

ginfo("channel=%d, cmd=0x%x, txlen=%ld\n", channel, cmd, txlen);
  DEBUGASSERT(pktbuf != NULL && txbuf != NULL);
  DEBUGASSERT(channel < 4);
  DEBUGASSERT(cmd < (1 << 6));

if (txlen < 1 || txlen > 2) { DEBUGPANIC(); return ERROR; }
  if (len > pktlen) { DEBUGPANIC(); return ERROR; }

/* Copy Packet Header to Packet Buffer */
  memcpy(pktbuf,
         header,
         sizeof(header));  /* 4 bytes */

/* Return the Packet Length */
  return len;
}
```

The code looks highly similar!

![Rendering graphics on PinePhone with Apache NuttX RTOS](https://lupyuen.github.io/images/dsi3-title.jpg)

## Test MIPI DSI for NuttX Kernel

_How do we test the MIPI DSI Driver in the NuttX Kernel?_

Right now we have implemented the following in the NuttX Kernel...

-   Driver for MIPI Display Serial Interface (DSI)
-   Driver for MIPI Display Physical Layer (D-PHY)

But to render graphics on PinePhone we need the following drivers, which are still in Zig, pending conversion to C...

-   Driver for Display Backlight
-   Driver for Timing Controller TCON0
-   Driver for Power Mgmt IC
-   Driver for LCD Panel
-   Driver for Display Engine

Running an Integration Test across the C and Zig Drivers will be a little interesting. Here's how we run the Integration Test...

We created this program in Zig that calls the C and Zig Drivers, in the right sequence...

https://github.com/lupyuen/pinephone-nuttx/blob/bc560cea04f601542eb1d3d71fb00dbc647d982d/render.zig#L1143-L1176

Then we compile the Zig Test Program targeting PinePhone...

```bash
  ##  Configure NuttX
  cd nuttx
  ./tools/configure.sh pinephone:nsh
  make menuconfig

##  Select "System Type > Allwinner A64 Peripheral Selection > DE"
  ##  Select "System Type > Allwinner A64 Peripheral Selection > RSB"
  ##  Select "Build Setup > Debug Options > Graphics Debug Features > Error + Warnings + Info"
  ##  Select "Build Setup > Debug Options > Battery-related Debug Features > Error + Warnings + Info"
  ##  Select "Device Drivers > Framebuffer Overlay Support"
  ##  Save and exit menuconfig

##  Build NuttX
  make

##  Download the Zig Test Program
  pushd $HOME
  git clone https://github.com/lupyuen/pinephone-nuttx
  cd pinephone-nuttx

##  Compile the Zig App for PinePhone 
  ##  (armv8-a with cortex-a53)
  ##  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
  zig build-obj \
    --verbose-cimport \
    -target aarch64-freestanding-none \
    -mcpu cortex_a53 \
    -isystem "$HOME/nuttx/nuttx/include" \
    -I "$HOME/nuttx/apps/include" \
    render.zig

##  Copy the compiled app to NuttX and overwrite `hello.o`
  ##  TODO: Change "$HOME/nuttx" to your NuttX Project Directory
  cp render.o \
    $HOME/nuttx/apps/examples/hello/*hello.o

##  Return to the NuttX Folder
  popd

##  Link the Compiled Zig App with NuttX
  make
```

[(Or download the binaries here)](https://github.com/lupyuen/pinephone-nuttx/releases/tag/v1.2.1)

We boot NuttX on PinePhone and run the Zig Test Program...

```text
NuttShell (NSH) NuttX-11.0.0-pinephone

nsh> uname -a
NuttX 11.0.0-pinephone 2a1577a-dirty Dec  9 2022 13:57:47 arm64 pinephone

nsh> hello 0
```

[(Source)](https://gist.github.com/lupyuen/f1a02068aeb0785278c482116a4eedc7)

Yep our Zig Test Program renders graphics successfully on PinePhone! (Pic above)

Which means the NuttX Kernel Drivers for MIPI DSI are working OK!

Here's the Test Log for our Zig Test Program running on NuttX and PinePhone...

-   [Test Log for NuttX MIPI DSI on PinePhone](https://gist.github.com/lupyuen/f1a02068aeb0785278c482116a4eedc7)

_What about Unit Testing? Can we test the MIPI DSI / D-PHY Driver without other drivers?_

Yep! Our MIPI DSI Driver simply writes values to a bunch of A64 Hardware Registers, like so: [a64_mipi_dsi.c](https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/a64_mipi_dsi.c#L633-L646)

```c
  /* DSI Configuration Register 1 (A31 Page 846)
   * Set Video_Start_Delay (Bits 4 to 16) to 1468 (Line Delay)
   * Set Video_Precision_Mode_Align (Bit 2) to 1 (Fill Mode)
   * Set Video_Frame_Start (Bit 1) to 1 (Precision Mode)
   * Set DSI_Mode (Bit 0) to 1 (Video Mode)
   * Note: Video_Start_Delay is actually 13 bits, not 8 bits as stated
   * in A31 User Manual
   */

#define DSI_BASIC_CTL1_REG (A64_DSI_ADDR + 0x14)
  #define DSI_MODE                   (1 << 0)
  #define VIDEO_FRAME_START          (1 << 1)
  #define VIDEO_PRECISION_MODE_ALIGN (1 << 2)
  #define VIDEO_START_DELAY(n)       (n << 4)

dsi_basic_ctl1 = VIDEO_START_DELAY(1468) |
                   VIDEO_PRECISION_MODE_ALIGN |
                   VIDEO_FRAME_START |
                   DSI_MODE;
  putreg32(dsi_basic_ctl1, DSI_BASIC_CTL1_REG);

// Include Test Code
  #include "../../pinephone-nuttx/test/test_a64_mipi_dsi2.c"
```

So we only need to ensure that the Hardware Addresses and the Written Values are correct.

To do that, we use Assertion Checks to verify the Addresses and Values: [test_a64_mipi_dsi2.c](https://github.com/lupyuen/pinephone-nuttx/blob/main/test/test_a64_mipi_dsi2.c#L34-L35)

```c
  // Test Code
  DEBUGASSERT(DSI_BASIC_CTL1_REG == 0x1ca0014);
  DEBUGASSERT(dsi_basic_ctl1 == 0x5bc7);
```

If the Addresses or Values are incorrect, our MIPI DSI Driver halts with an Assertion Failure.

(We remove the Assertion Checks in the final version of our driver)

_What about a smaller, self-contained Unit Test for MIPI DSI?_

Here's the Unit Test that verifies MIPI DSI Packets (Long / Short  / Short with Parameter) are composed correctly...

https://github.com/lupyuen/pinephone-nuttx/blob/46f055eceae268fa7ba20d69c12d4823491a89b9/test/test_mipi_dsi.c#L1-L109

_Can we test the MIPI DSI Driver on our Local Computer? Without running on PinePhone?_

Most certainly! In fact we test the MIPI DSI Driver on our Local Computer first before testing on PinePhone. Here's how...

Remember that our MIPI DSI Driver simply writes values to a bunch of A64 Hardware Registers. So we only need to ensure that the Hardware Addresses and the Written Values are correct.

We created a Test Scaffold that simulates the NuttX Build Environment...

https://github.com/lupyuen/pinephone-nuttx/blob/44167d81edbd054d3285ca3a6087926e6fc9ce79/test/test.c#L7-L51

Then we compile the Test Scaffold and run it on our Local Computer...

https://github.com/lupyuen/pinephone-nuttx/blob/cdb6bbc8e57ef02104bdbde721f8ff6787d74efc/test/run.sh#L9-L36

Note that we capture the [Actual Test Log](test/test.log) and we `diff` it with the [Expected Test Log](test/expected.log). That's how we detect discrepancies in the Hardware Addresses and the Written Values...

https://github.com/lupyuen/pinephone-nuttx/blob/c04f1447933665df207a42f626c726ef7a7def65/test/test.log#L4-L20

## Test Timing Controller TCON0 Driver for NuttX Kernel

We're adding the Timing Controller TCON0 Driver to NuttX Kernel...

-   [arch/arm64/src/a64/a64_tcon0.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/tcon/arch/arm64/src/a64/a64_tcon0.c)

Right now we have implemented the following in the NuttX Kernel...

-   Driver for MIPI Display Serial Interface (DSI)
-   Driver for MIPI Display Physical Layer (D-PHY)
-   Driver for Timing Controller TCON0

But to render graphics on PinePhone we need the following drivers, which are still in Zig, pending conversion to C...

-   Driver for Display Backlight
-   Driver for Power Mgmt IC
-   Driver for LCD Panel
-   Driver for Display Engine

So we created this Test Program in Zig that calls the C and Zig Drivers, in the right sequence...

https://github.com/lupyuen/pinephone-nuttx/blob/15111a227a62204b2bd6b13c489ff4a972e6d8ad/render.zig#L1146-L1199

[(Download the binaries here)](https://github.com/lupyuen/pinephone-nuttx/releases/tag/v1.2.0)

We boot NuttX on PinePhone and run the Zig Test Program...

```text
NuttShell (NSH) NuttX-11.0.0-pinephone

nsh> uname -a
NuttX 11.0.0-pinephone 893b147 Dec 14 2022 23:01:27 arm64 pinephone

nsh> hello 0
```

[(Source)](https://gist.github.com/lupyuen/33d7cc006e841a9e5fdff264b4c759c4)

Our Zig Test Program renders the Test Pattern successfully on PinePhone. [(Like this)](https://lupyuen.github.io/images/dsi3-title.jpg)

Here's the Test Log, with Graphics Logging Enabled...

-   [NuttX Kernel TCON0 Test Log](https://gist.github.com/lupyuen/33d7cc006e841a9e5fdff264b4c759c4)

We also tested with Graphics Logging Disabled, to preempt any timing issues...

-   [NuttX Kernel TCON0 Test Log (Graphics Logging Disabled)](https://gist.github.com/lupyuen/61a1374c9ea6a1b7826488da688e8c6c)

## Test Display Engine Driver for NuttX Kernel

We're adding the Display Engine Driver to NuttX Kernel...

-   [arch/arm64/src/a64/a64_de.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/de/arch/arm64/src/a64/a64_de.c)

Right now we have implemented the following in the NuttX Kernel...

-   Driver for MIPI Display Serial Interface (DSI)
-   Driver for MIPI Display Physical Layer (D-PHY)
-   Driver for Timing Controller TCON0
-   Driver for Display Engine

But to render graphics on PinePhone we need the following drivers, which are still in Zig, pending conversion to C...

-   Driver for Display Backlight
-   Driver for Power Mgmt IC
-   Driver for LCD Panel
-   Driver for Pulse-Width Modulation
-   Driver for Reduced Serial Bus

So we created this Test Program in Zig that calls the C and Zig Drivers, in the right sequence...

https://github.com/lupyuen/pinephone-nuttx/blob/720b8042aa2f86b336947b8ce4744872a77d13f5/render.zig#L1146-L1194

[(Download the binaries here)](https://github.com/lupyuen/pinephone-nuttx/releases/tag/v1.2.0)

We boot NuttX on PinePhone and run the Zig Test Program...

```text
NuttShell (NSH) NuttX-11.0.0-pinephone

nsh> uname -a
NuttX 11.0.0-pinephone 7d85079-dirty Dec 17 2022 11:43:03 arm64 pinephone

nsh> hello 0
```

[(Source)](https://gist.github.com/lupyuen/f76ec0bcafce670220ab304a70c28fab)

Our Zig Test Program renders the Test Pattern successfully on PinePhone. [(Like this)](https://lupyuen.github.io/images/de3-title.jpg)

Here's the Test Log, with Graphics Logging Enabled...

-   [NuttX Kernel Display Engine Test Log](https://gist.github.com/lupyuen/f76ec0bcafce670220ab304a70c28fab)

We also tested with Graphics Logging Disabled, to preempt any timing issues...

-   [NuttX Kernel TCON0 Test Log (Graphics Logging Disabled)](https://gist.github.com/lupyuen/ff133730c07730cb3b588a5027e7f524)

## Missing Pixels in PinePhone Image

We've just implemented the NuttX Kernel Drivers for MIPI Display Serial Interface, Timing Controller TCON0, Display Engine, Reduced Serial Bus, Power Management Integrated Circuit and LCD Panel...

-   ["NuttX RTOS for PinePhone: MIPI Display Serial Interface"](https://lupyuen.github.io/articles/dsi3)

-   ["NuttX RTOS for PinePhone: Display Engine"](https://lupyuen.github.io/articles/de3)

-   ["NuttX RTOS for PinePhone: LCD Panel"](https://lupyuen.github.io/articles/lcd)

And we're adding the Framebuffer Driver to NuttX Kernel...

https://github.com/apache/nuttx/pull/7988

When we run the `fb` NuttX Example App, we see missing pixels in the rendered image...

-   Inside the Yellow Box is supposed to be an Orange Box

-   Inside the Orange Box is supposed to be a Red Box

![Missing Pixels in PinePhone Image](https://lupyuen.github.io/images/fb-test2.jpg)

The missing pixels magically appear later in a curious pattern...

-   [Watch the Demo on YouTube](https://www.youtube.com/shorts/WD5AJj7Rz5U)

There seems to be a problem with Framebuffer DMA / Display Engine / Timing Controller TCON0?

According to the video, the pixels are actually written correctly to the RAM Framebuffer. But the pixels at the lower half don't get pushed to the display until the next screen refresh.

There seems to be a lag between the writing of pixels to framebuffer, and the pushing of pixels to the display over DMA / Display Engine / Timing Controller TCON0.

Here's the fix for this lag...

## Fix Missing Pixels in PinePhone Image

In the previous section we saw that there was a lag pushing pixels from the RAM Framebuffer to the PinePhone Display (over DMA / Display Engine / Timing Controller TCON0).

Can we overcome this lag by copying the RAM Framebuffer to itself, forcing the display to refresh? This sounds very strange, but yes it works!

From [pinephone_display.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/pixel/boards/arm64/a64/pinephone/src/pinephone_display.c#L472-L513):

```c
// Update the display when there is a change to the framebuffer.
// (ioctl Entrypoint: FBIO_UPDATE)
static int pinephone_updatearea(
  struct fb_vtable_s *vtable,   // Framebuffer driver object
  const struct fb_area_s *area  // Updated area of framebuffer
) {
  uint8_t *fb = (uint8_t *)g_pinephone_fb0;
  const size_t fbsize = sizeof(g_pinephone_fb0);

// Copy the entire framebuffer to itself,
  // to fix the missing pixels.
  // Not sure why this works.
  for (int i = 0; i < fbsize; i++) {

// Declare as volatile to prevent compiler optimization
    volatile uint8_t v = fb[i];
    fb[i] = v;
  }
  return OK;
}
```

With the code above, the Red, Orange and Yellow Boxes are now rendered correctly in our NuttX Framebuffer Driver for PinePhone. (Pic below)

_Who calls pinephone_updatearea?_

After writing the pixels to the RAM Framebuffer, NuttX Apps will call `ioctl(FBIO_UPDATE)` to update the display.

This triggers `pinephone_updatearea` in our NuttX Framebuffer Driver: [fb_main.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/pixel/examples/fb/fb_main.c#L265-L274)

```c
// Omitted: NuttX App writes pixels to RAM Framebuffer

// Update the Framebuffer
#ifdef CONFIG_FB_UPDATE
  ret = ioctl(    // I/O Command
    state->fd,    // Framebuffer File Descriptor
    FBIO_UPDATE,  // Update the Framebuffer
    (unsigned long)((uintptr_t)area)  // Updated area
  );
#endif
```

![Fixed Missing Pixels in PinePhone Image](https://lupyuen.github.io/images/fb-test3.jpg)

_How do other PinePhone operating systems handle this?_

We might need to handle TCON0 Vertical Blanking (`TCON0_Vb_Int_En` / `TCON0_Vb_Int_Flag`) and TCON0 CPU Trigger Mode Finish (`TCON0_Tri_Finish_Int_En` / `TCON0_Tri_Finish_Int_Flag`) like this...

-   [sun4i_tcon_enable_vblank](https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/sun4i/sun4i_tcon.c#L225-L242)

-   [sun4i_tcon_handler](https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/sun4i/sun4i_tcon.c#L746-L777)

[(More about sun4i_tcon_handler)](https://gist.github.com/lupyuen/214788deabdb37659e806a463f8acc50)

p-boot Bootloader seems to handle every TCON0 CPU Trigger Mode Finish (`TCON0_Tri_Finish_Int_En` / `TCON0_Tri_Finish_Int_Flag`) by updating the Display Engine Registers. Which sounds odd...

1.  Render Loop waits forever for `EV_VBLANK`: [dtest.c](https://megous.com/git/p-boot/tree/src/dtest.c#n327)

1.  `EV_VBLANK` is triggered by `display_frame_done`: [gui.c](https://megous.com/git/p-boot/tree/src/gui.c#n64)

1.  `display_frame_done` is triggered by TCON0 CPU Trigger Mode Finish: [display.c](https://megous.com/git/p-boot/tree/src/display.c#n2005)

1.  Render Loop handles `EV_VBLANK` by redrawing and calling `display_commit`:  [dtest.c](https://megous.com/git/p-boot/tree/src/dtest.c#n338)

1.  `display_commit` updates the Display Engine Registers, including the Framebuffer Addresses: [display.c](https://megous.com/git/p-boot/tree/src/display.c#n2017)

Can we handle TCON0 CPU Trigger Mode Finish without refreshing the Display Engine Registers?

# Merge PinePhone into NuttX Mainline

Read the article...

-   ["Preparing a Pull Request for Apache NuttX RTOS"](https://lupyuen.github.io/articles/pr)

We're merging PinePhone into NuttX Mainline!

NuttX Mainline now supports Generic Interrupt Controller Version 2...

-   ["arch/arm64: Add support for Generic Interrupt Controller Version 2"](https://github.com/apache/incubator-nuttx/pull/7630)

We created a NuttX Board Configuration for PinePhone that will boot to NuttX Shell (NSH)...

-   ["arch/arm64: Add support for PINE64 PinePhone"](https://github.com/apache/incubator-nuttx/pull/7692)

And now PinePhone is officially supported by Apache NuttX RTOS!

-   ["PinePhone is now supported by Apache NuttX RTOS"](https://lupyuen.github.io/articles/uboot#appendix-pinephone-is-now-supported-by-apache-nuttx-rtos)

Here's how we prepared the Pull Requests for NuttX...

-   ["Preparing a Pull Request for Apache NuttX RTOS"](https://lupyuen.github.io/articles/pr)

# LVGL on NuttX on PinePhone

Read the article...

-   ["NuttX RTOS for PinePhone: Boot to LVGL"](https://lupyuen.github.io/articles/lvgl2)

LVGL on Apache NuttX RTOS (Mainline) renders correctly on PinePhone! (Pic below)

Just select the LVGL Demo App that's bundled with Apache NuttX RTOS. Here are the settings in `make menuconfig`...

Enable "__Application Configuration__ > __Graphics Support__ > __Light and Versatile Graphics Library (LVGL)__"

Enable "__LVGL__ > __Enable Framebuffer Port__"

Browse into "__LVGL__ > __LVGL Configuration__"

-   In "__Color Settings__"

Set __Color Depth__ to "__32: ARGB8888__"

-   In "__Memory settings__"
    
    Set __Size of Memory__ to __64__

-   In "__HAL Settings__"

Set __Default Dots Per Inch__ to __250__

-   In "__Demos__"

Enable "__Show Some Widgets__"

Enable "__Application Configuration__ > __Examples__ > __LVGL Demo__"

Touch Input is not supported yet. We're working on it!

For details on the NuttX Framebuffer for PinePhone (and how it works with LVGL) check out this article...

-   ["NuttX RTOS for PinePhone: Framebuffer"](https://lupyuen.github.io/articles/fb)

![LVGL on NuttX on PinePhone](https://lupyuen.github.io/images/fb-lvgl.jpg)

## LVGL Settings for PinePhone

When we run the LVGL Demo App on PinePhone with Apache NuttX RTOS, it renders a dense screen that's not so Touch-Friendly...

![Before changing LVGL Settings for PinePhone](https://lupyuen.github.io/images/fb-lvgl3.jpg)

Let's tweak the LVGL Settings to make our LVGL App more accessible. Modify this LVGL Source File...

[apps/graphics/lvgl/lvgl/demos/widgets/lv_demo_widgets.c](https://github.com/lvgl/lvgl/blob/v8.3.3/demos/widgets/lv_demo_widgets.c#L96-L145)

```c
// Insert this
#include <stdio.h>

// Modify this function
void lv_demo_widgets(void)
{
    // Note: PinePhone has width 720 pixels.
    // LVGL will set Display Size to Large, which looks really tiny.
    // Shouldn't this code depend on DPI? (267 DPI for PinePhone)
    if(LV_HOR_RES <= 320) disp_size = DISP_SMALL;
    else if(LV_HOR_RES < 720) disp_size = DISP_MEDIUM;
    else disp_size = DISP_LARGE;

// Insert this: Print warning if font is missing
    #undef LV_LOG_WARN
    #define LV_LOG_WARN(s) puts(s)

// Insert this: Change Display Size from Large to Medium, to make Widgets easier to tap
    printf("Before: disp_size=%d\n", disp_size);
    disp_size = DISP_MEDIUM;
    printf("After: disp_size=%d\n", disp_size);

// Existing Code
    font_large = LV_FONT_DEFAULT;
    font_normal = LV_FONT_DEFAULT;

lv_coord_t tab_h;
    if(disp_size == DISP_LARGE) {
        ...
    }
    // For Medium Display Size...
    else if(disp_size == DISP_MEDIUM) {
        // Change this: Increase Tab Height from 45 to 70, to make Tabs easier to tap
        tab_h = 70;
        // Previously: tab_h = 45;

#if LV_FONT_MONTSERRAT_20
        font_large     = &lv_font_montserrat_20;
#else
        LV_LOG_WARN("LV_FONT_MONTSERRAT_20 is not enabled for the widgets demo. Using LV_FONT_DEFAULT instead.");
#endif
#if LV_FONT_MONTSERRAT_14
        font_normal    = &lv_font_montserrat_14;
#else
        LV_LOG_WARN("LV_FONT_MONTSERRAT_14 is not enabled for the widgets demo. Using LV_FONT_DEFAULT instead.");
#endif
    }
```

(Maybe we should modify the code above to include DPI? PinePhone's Display has 267 DPI)

Configure LVGL with these settings...

-   ["LVGL Calls Our Driver"](https://lupyuen.github.io/articles/touch2#lvgl-calls-our-driver)

And add the fonts...

-   Browse into "__LVGL__ > __LVGL Configuration__"
    
    -   In "__Font usage__ > __Enable built-in fonts__"

Enable "__Montserrat 20__"

The LVGL Demo App is now less dense and easier to use...

-   [Watch the Demo on YouTube](https://www.youtube.com/shorts/De5ZehlIka8)

(Shot at ISO 800, F/5.6, Manual Focus on Sony NEX-7. Post-processed for Brightness, Constrast and White Point)

_What if we increase the Default Font Size? From Montserrat 14 to Montserrat 20?_

Let's increase the Default Font Size from 14 to 20...

-   Browse into "__LVGL__ > __LVGL Configuration__"
    
    -   In "__Font usage__ > __Select theme default title font__"

Select "__Montserrat 20__"

We run the LVGL Demo App as is, leaving Display Size `disp_size` as default `DISP_LARGE`.

Now the text is legible, but some controls are squished...

-   [Watch the Demo on YouTube](https://www.youtube.com/watch?v=N-Yc2jj3TtQ)

(Shot at ISO 400, F/5.0, Manual Focus, Exposure 0.3 on Sony NEX-7. No post-processing)

We need to increase the Default Font Size from 14 to 20, AND set Display Size `disp_size` to `DISP_MEDIUM`. And we will get this...

![After changing LVGL Settings for PinePhone](https://lupyuen.github.io/images/lvgl2-title.jpg)

More details here...

-   ["NuttX RTOS for PinePhone: Boot to LVGL"](https://lupyuen.github.io/articles/lvgl2)

## LVGL Demos on PinePhone

_We've seen the LVGL Widgets Demo on NuttX for PinePhone. What about other demos?_

Yep there are 5 LVGL Demos available in `make menuconfig`...

-   Browse into "__LVGL__ > __LVGL Configuration__"
    
    -   In "__Demos__", select one or more of the these demos...
        
        "__Show Some Widgets__"

"__Demonstrate the usage of encoder and keyboard__"

"__Benchmark your system__"

"__Stress test for LVGL__"

"__Music player demo__"

For Music Player Demo, we need these fonts...

-   Browse into "__LVGL__ > __LVGL Configuration__"
    
    -   In "__Font usage__", select...

"__Montserrat 16__"

"__Montserrat 20__"

"__Montserrat 22__"
        
        "__Montserrat 32__"

To run the demos on PinePhone...

```text
nsh> lvgldemo
Usage: lvgldemo demo_name
demo_name:
  widgets
  keypad_encoder
  benchmark
  stress
  music
```

[(Source)](https://gist.github.com/lupyuen/b96ed96db295334db1cfabf461efad83)

We've seen the LVGL Widgets Demo...

-   [LVGL Widgets Demo on YouTube](https://www.youtube.com/watch?v=N-Yc2jj3TtQ)

Here's the LVGL Music Player Demo...

-   [LVGL Music Player Demo on YouTube](https://www.youtube.com/watch?v=_cxCnKNibtA)

And the LVGL Benchmark Demo...

-   [LVGL Benchmark Demo on YouTube](https://www.youtube.com/watch?v=deBzb-VbHck)

From the video we see the LVGL Benchmark Numbers...

- Weighted Frames Per Second: 20
- Opa Speed: 100%

| Slow but common cases | Frames Per Sec |
|-----------------------|-------------------|
| Image RGB | 19
| Image RGB + Opa | 17
| Image ARGB | 18
| Image ARGB + Opa | 17
| Image ARGB Recolor | 17
| Image ARGB Recolor + Opa | 16
| Substr Image | 19

| All Cases | Frames Per Sec |
|-----------|-------------------|
| Rectangle | 24
| Rectangle + Opa | 23
| Rectangle Rounded | 23
| Rectangle Rounded + Opa | 21
| Circle | 23
| Circle + Opa | 20
| Border | 24
| Border + Opa | 24
| Border Rounded | 24
| (Many many more) |

More details here...

-   ["NuttX RTOS for PinePhone: Boot to LVGL"](https://lupyuen.github.io/articles/lvgl2)

Note that the LVGL Demos start automatically when NuttX boots on PinePhone. Let's talk about this...

## Boot to LVGL on PinePhone

_Can we boot NuttX on PinePhone, directly to LVGL? Without a Serial Cable?_

Sure can! In the previous section we talked about selecting the LVGL Demos.

To boot directly to an LVGL Demo, make sure only 1 LVGL Demo is selected.

[(Because of this)](https://github.com/apache/nuttx-apps/pull/1494)

Then in `make menuconfig`...

1. RTOS Features > Tasks and Scheduling

-  Set "Application entry point" to `lvgldemo_main`

(INIT_ENTRYPOINT)

-  Set "Application entry name" to `lvgldemo_main`

(INIT_ENTRYNAME)

2. Application Configuration > NSH Library

- Disable "Have architecture-specific initialization"

(NSH_ARCHINIT)

NuttX on PinePhone now boots to the LVGL Touchscreen Demo, without a Serial Cable! (Pic below)

-   [LVGL Music Player Demo on YouTube](https://www.youtube.com/watch?v=_cxCnKNibtA)

_Why disable "NSH Architecture-Specific Initialization"?_

Normally the NSH NuttX Shell initialises the Display Driver and Touch Panel on PinePhone.

But since we're not running NSH Shell, we'll have to initialise the Display Driver and Touch Panel in our LVGL Demo App.

This is explained here...

-   [lvgldemo.c](https://github.com/apache/nuttx-apps/blob/master/examples/lvgldemo/lvgldemo.c#L42-L59)

_Now that we can boot NuttX to an LVGL Touchscreen App, what next?_

Maybe we can create an LVGL Terminal App? That will let us interact with the NSH NuttX Shell?

LVGL already provides an Onscreen Keyboard that works on PinePhone NuttX.

More details here...

-   ["NuttX RTOS for PinePhone: Boot to LVGL"](https://lupyuen.github.io/articles/lvgl2)

![NuttX on PinePhone now boots to the LVGL Touchscreen Demo, without a Serial Cable](https://lupyuen.github.io/images/lvgl2-title.jpg)

# PinePhone Touch Panel

Read the article...

-   ["NuttX RTOS for PinePhone: Touch Panel"](https://lupyuen.github.io/articles/touch2)

Now that we can render LVGL Graphical User Interfaces, let's handle Touch Input!

Here's everything we know about PinePhone's Touch Panel...

-   [__"Touch Panel"__](https://lupyuen.github.io/articles/pio#touch-panel)

According to our [__Test Code__](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c4991b1503387d57821d94a549425bcd8f268841/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L316-L355)...

-   __I2C Address__ is __0x5D__

-   __I2C Frequency__ is __400 kHz__

(What's the max?)

-   __I2C Register Addresses__ are 16-bit

(Send MSB before LSB, so we should swap the bytes)

-   Reading I2C Register __0x8140__ (Product ID) will return the bytes...

```text
    39 31 37 53
    ```
    
    Which is ASCII for "__`917S`__"

(Goodix GT917S Touch Panel)

This is how we read the Product ID from the Touch Panel: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c4991b1503387d57821d94a549425bcd8f268841/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L316-L355)

```c
// Product ID (LSB 4 bytes)
#define GOODIX_REG_ID 0x8140

// Read Touch Panel over I2C
static void touch_panel_read(struct i2c_master_s *i2c)
{
  uint32_t freq = 400000;  // 400 kHz
  uint16_t addr = 0x5d;  // Default I2C Address for Goodix GT917S
  uint16_t reg = GOODIX_REG_ID;  // Read Product ID
  uint8_t regbuf[2] = { reg >> 8, reg & 0xff };  // Flip the bytes

// Erase the receive buffer
  uint8_t buf[4];
  ssize_t buflen = sizeof(buf);
  memset(buf, 0xff, sizeof(buf));

// Compose the I2C Messages
  struct i2c_msg_s msgv[2] =
  {
    {
      .frequency = freq,
      .addr      = addr,
      .flags     = 0,
      .buffer    = regbuf,
      .length    = sizeof(regbuf)
    },
    {
      .frequency = freq,
      .addr      = addr,
      .flags     = I2C_M_READ,
      .buffer    = buf,
      .length    = buflen
    }
  };

// Execute the I2C Transfer
  int ret = I2C_TRANSFER(i2c, msgv, 2);
  if (ret < 0) { _err("I2C Error: %d\n", ret); return; }

// Dump the receive buffer
  infodumpbuffer("buf", buf, buflen);
  // Shows "39 31 37 53" or "917S"
}
```

To detect Touch Events, we'll need to handle the Interrupts triggered by Touch Panel.

Based on our research, PinePhone's Touch Panel Interrupt (CTP-INT) is connected at PH4.

Right now we poll PH4 (instead of handling interrupts) because it's easier: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/e249049370d21a988912f2fb95a21514863dfe8a/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L283-L317)

```c
// Test Touch Panel Interrupt by Polling as GPIO Input.
// Touch Panel Interrupt (CTP-INT) is at PH4.
// Configure for GPIO Input
#define CTP_INT (PIO_INPUT | PIO_PORT_PIOH | PIO_PIN4)

static void touch_panel_read(struct i2c_master_s *i2c);

// Poll for Touch Panel Interrupt (PH4) by reading as GPIO Input
void touch_panel_initialize(struct i2c_master_s *i2c)
{

// Configure the Touch Panel Interrupt for GPIO Input
  int ret = a64_pio_config(CTP_INT);
  DEBUGASSERT(ret == 0);

// Poll the Touch Panel Interrupt as GPIO Input
  bool prev_val = false;
  for (int i = 0; i < 6000; i++) {  // Poll for 60 seconds

// Read the GPIO Input
    bool val = a64_pio_read(CTP_INT);

// If value has changed...
    if (val != prev_val) {

// Print the value
      if (val) { up_putc('+'); }
      else     { up_putc('-'); }
      prev_val = val;

// If we have just transitioned from Low to High...
      if (val) {

// Read the Touch Panel over I2C
        touch_panel_read(i2c);
      }
    }

// Wait a while
    up_mdelay(10);
  }
}
```

To read the Touch Coordinates, we do this: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/e249049370d21a988912f2fb95a21514863dfe8a/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L338-L370)

```c
#define GOODIX_REG_ID 0x8140
#define GOODIX_READ_COORD_ADDR 0x814E
#define GOODIX_POINT1_X_ADDR 0x8150

// Read Touch Panel over I2C
static void touch_panel_read(struct i2c_master_s *i2c)
{
  // Read the Product ID
  uint8_t id[4];
  touch_panel_i2c_read(i2c, GOODIX_REG_ID, id, sizeof(id));
  // Shows "39 31 37 53" or "917S"

// Read the Touch Panel Status
  uint8_t status[1];
  touch_panel_i2c_read(i2c, GOODIX_READ_COORD_ADDR, status, sizeof(status));
  // Shows "81"

const uint8_t status_code    = status[0] & 0x80;  // Set to 0x80
  const uint8_t touched_points = status[0] & 0x0f;  // Set to 0x01

if (status_code != 0 &&  // If Touch Panel Status is OK and...
      touched_points >= 1) {  // Touched Points is 1 or more

// Read the First Touch Coordinates
    uint8_t touch[6];
    touch_panel_i2c_read(i2c, GOODIX_POINT1_X_ADDR, touch, sizeof(touch));
    // Shows "92 02 59 05 1b 00"

// Decode the Touch Coordinates
    const uint16_t x = touch[0] + (touch[1] << 8);
    const uint16_t y = touch[2] + (touch[3] << 8);
    _info("touch x=%d, y=%d\n", x, y);
    // Shows "touch x=658, y=1369"
  }

// Set the Touch Panel Status to 0
  touch_panel_set_status(i2c, 0);
}
```

When we touch PinePhone near the Lower Right Corner, we see the Touch Coordinates x=658, y=1369 (which is quite close to the 720 x 1440 screen size)...

```text
twi_transfer: TWI0 count: 1
twi_wait: TWI0 Waiting...
twi_put_addr: TWI address 7bits+r/w = 0xba
twi_wait: TWI0 Awakened with result: 0
-+twi_transfer: TWI0 count: 2
twi_wait: TWI0 Waiting...
twi_put_addr: TWI address 7bits+r/w = 0xba
twi_put_addr: TWI address 7bits+r/w = 0xbb
twi_wait: TWI0 Awakened with result: 0
buf (0x40a8fd18):
0000  39 31 37 53                                      917S            
twi_transfer: TWI0 count: 2
twi_wait: TWI0 Waiting...
twi_put_addr: TWI address 7bits+r/w = 0xba
twi_put_addr: TWI address 7bits+r/w = 0xbb
twi_wait: TWI0 Awakened with result: 0
buf (0x40a8fd08):
0000  81                                               .               
twi_transfer: TWI0 count: 2
twi_wait: TWI0 Waiting...
twi_put_addr: TWI address 7bits+r/w = 0xba
twi_put_addr: TWI address 7bits+r/w = 0xbb
twi_wait: TWI0 Awakened with result: 0
buf (0x40a8fd20):
0000  92 02 59 05 1b 00                                ..Y...          
touch_panel_read: touch x=658, y=1369
```

[(Source)](https://gist.github.com/lupyuen/b1ed009961c4202133879b760cb22833)

Yep we can read the Touch Coordinates correctly, with polling! (But not so efficient)

Let's handle Interrupts from the Touch Panel...

## Handle Interrupts from Touch Panel

In the previous section we've read the Touch Panel by Polling. Which is easier but inefficient.

Eventually we'll use an Interrupt Handler to monitor Touch Panel Interrupts. This is how we monitor PH4 for interrupts: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c3eccc67d879806a015ae592205e641dcffa7d09/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L255-L328)

```c
// Touch Panel Interrupt (CTP-INT) is at PH4
#define CTP_INT (PIO_EINT | PIO_PORT_PIOH | PIO_PIN4)

// Register the Interrupt Handler for Touch Panel
void touch_panel_initialize(void) {

// Attach the PIO Interrupt Handler for Port PH
  if (irq_attach(A64_IRQ_PH_EINT, touch_panel_interrupt, NULL) < 0) {
    _err("irq_attach failed\n");
    return ERROR;
  }

// Enable the PIO Interrupt for Port PH
  up_enable_irq(A64_IRQ_PH_EINT);

// Configure the Touch Panel Interrupt
  int ret = a64_pio_config(CTP_INT);
  DEBUGASSERT(ret == 0);

// Enable the Touch Panel Interrupt
  ret = a64_pio_irqenable(CTP_INT);
  DEBUGASSERT(ret == 0);
}

// Interrupt Handler for Touch Panel
static int touch_panel_interrupt(int irq, void *context, void *arg) {

// Print something when interrupt is triggered
  up_putc('.');
  return OK;
}
```

When we run this code, it generates a non-stop stream of "." characters.

Which means that the Touch Input Interrupt is generated continuously. Without touching the screen!

_Is our Interrupt Handler code correct?_

Yep our Interrupt Handler code is correct! But through our experiments we discovered one thing...

To stop the repeated Touch Input Interrupts, we need to set the __Touch Panel Status to 0__! Like so: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c3eccc67d879806a015ae592205e641dcffa7d09/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L470-L500)

```c
// When the Touch Input Interrupt is triggered...
// Set the Touch Panel Status to 0
touch_panel_set_status(i2c, 0);
...

#define GOODIX_READ_COORD_ADDR 0x814E  // Touch Panel Status (Read / Write)
#define CTP_FREQ 400000  // I2C Frequency: 400 kHz
#define CTP_I2C_ADDR 0x5d  // Default I2C Address for Goodix GT917S

// Set the Touch Panel Status
static int touch_panel_set_status(
  struct i2c_master_s *i2c,  // I2C Bus
  uint8_t status  // Status value to be set
) {
  uint16_t reg = GOODIX_READ_COORD_ADDR;  // I2C Register
  uint32_t freq = CTP_FREQ;  // 400 kHz
  uint16_t addr = CTP_I2C_ADDR;  // Default I2C Address for Goodix GT917S
  uint8_t buf[3] = {
    reg >> 8,    // Swap the bytes
    reg & 0xff,  // Swap the bytes
    status
  };

// Compose the I2C Message
  struct i2c_msg_s msgv[1] =
  {
    {
      .frequency = freq,
      .addr      = addr,
      .flags     = 0,
      .buffer    = buf,
      .length    = sizeof(buf)
    }
  };

// Execute the I2C Transfer
  const int msgv_len = sizeof(msgv) / sizeof(msgv[0]);
  int ret = I2C_TRANSFER(i2c, msgv, msgv_len);
  if (ret < 0) { _err("I2C Error: %d\n", ret); return ret; }
  return OK;
}
```

_So we set the Touch Panel Status inside our Interrupt Handler?_

But Interrupt Handlers aren't allowed to make I2C Calls!

We need to __forward the Interrupt__ to a Background Thread to handle. Like so: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c3eccc67d879806a015ae592205e641dcffa7d09/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L237-L253)

```c
// Interrupt Handler for Touch Panel
static int gt9xx_isr_handler(int irq, FAR void *context, FAR void *arg)
{
   FAR struct gt9xx_dev_s *priv = (FAR struct gt9xx_dev_s *)arg;

// Set the Interrupt Pending Flag
  irqstate_t flags = enter_critical_section();
  priv->int_pending = true;
  leave_critical_section(flags);

// Notify the Poll Waiters
  poll_notify(priv->fds, GT9XX_NPOLLWAITERS, POLLIN);
  return 0;
}
```

This notifies the File Descriptors `fds` that are waiting for Touch Input Interrupts to be triggered.

When the File Descriptor is notified, the Background Thread will become unblocked, and can call I2C to read the Touch Input.

Right now we don't have a Background Thread, so we poll and wait for the Touch Input Interrupt to be triggered: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/c3eccc67d879806a015ae592205e641dcffa7d09/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L293-L309)

```c
  // Poll for Touch Panel Interrupt
  // TODO: Move this
  for (int i = 0; i < 6000; i++) {  // Poll for 60 seconds

// If Touch Panel Interrupt has been triggered...
    if (priv->int_pending) {

// Read the Touch Panel over I2C
      touch_panel_read(i2c_dev);

// Reset the Interrupt Pending Flag
      priv->int_pending = false;
    }

// Wait a while
    up_mdelay(10);  // 10 milliseconds
  }
```

And it works!

```text
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
a64_pio_config: cfgaddr=0x1c208fc, intaddr=0x1c20a40, value=0x0, shift=16
touch_panel_initialize: v=0x10, m=0x10, a=0x1c20a50      
buf (0x40a8fd20):
0000  39 31 37 53                                      917S            
buf (0x40a8fd10):
0000  81                                               .               
buf (0x40a8fd28):
0000  19 01 e6 02 2a 00                                ....*.          
touch_panel_read: touch x=281, y=742
...     
buf (0x40a8fd20):
0000  39 31 37 53                                      917S            
buf (0x40a8fd10):
0000  81                                               .               
buf (0x40a8fd28):
0000  81 02 33 00 25 00                                ..3.%.          
touch_panel_read: touch x=641, y=51
...
buf (0x40a8fd20):
0000  39 31 37 53                                      917S            
buf (0x40a8fd10):
0000  81                                               .               
buf (0x40a8fd28):
0000  0f 00 72 05 14 00                                ..r...          
touch_panel_read: touch x=15, y=1394
```

[(Source)](https://gist.github.com/lupyuen/91a37a4b54f75f7386374a30821dc1b2)

Let's move this code into the NuttX Touch Panel Driver for PinePhone...

## NuttX Touch Panel Driver for PinePhone

We moved the code above into the NuttX Touch Panel Driver for PinePhone...

-   [drivers/input/gt9xx.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/touch2/drivers/input/gt9xx.c)

This is how we start the driver when NuttX boots: [pinephone_bringup.c](https://github.com/lupyuen2/wip-pinephone-nuttx/blob/touch2/boards/arm64/a64/pinephone/src/pinephone_bringup.c#L197-L204)

```c
#define CTP_I2C_ADDR 0x5d  // Default I2C Address for Goodix GT917S
ret = gt9xx_register("/dev/input0", i2c, CTP_I2C_ADDR, &g_pinephone_gt9xx);
```

And it works with the LVGL Demo App!

-   [Watch the Demo on YouTube](https://www.youtube.com/shorts/APge9bTt-ho)

Read the article...

-   ["NuttX RTOS for PinePhone: Touch Panel"](https://lupyuen.github.io/articles/touch2)

# LVGL Terminal for NuttX

Read the article...

-   ["NuttX RTOS for PinePhone: LVGL Terminal for NSH Shell"](https://lupyuen.github.io/articles/terminal)

Let's create a Terminal App in LVGL, that will let us interact with the NuttX NSH Shell...

-   [Watch the Demo on YouTube](https://www.youtube.com/watch?v=WdiXaMK8cNw)

-   [Source Code: lvglterm.c](https://github.com/lupyuen/lvglterm/blob/main/lvglterm.c)

-   [How to compile LVGL Terminal](https://github.com/lupyuen/lvglterm)

-   [Download the NuttX Image for PinePhone](https://github.com/lupyuen2/wip-pinephone-nuttx/releases/tag/nuttx-12.0.1)

![LVGL Terminal for NuttX](https://lupyuen.github.io/images/lvgl2-terminal2.jpg)

We begin by starting the NSH Task and piping a command to NSH Shell...

![Flow of LVGL Terminal for PinePhone on Apache NuttX RTOS](https://lupyuen.github.io/images/terminal-flow.jpg)

## Pipe a Command to NuttX NSH Shell

Our LVGL Terminal App needs to...

1.  Start the NuttX Task for NSH Shell

1.  Redirect the NSH Console Input / Output to LVGL

Here's a simple test that starts the NSH Task and sends a command to NSH Console via a POSIX Pipe: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/a9d67c135c458088946ed35c1b24be1b4aee3553/examples/lvgldemo/lvgldemo.c#L246-L390)

```c
void test_terminal(void) {

// Create the pipes
  int nsh_stdin[2];
  int nsh_stdout[2];
  int nsh_stderr[2];
  int ret;
  ret = pipe(nsh_stdin);  if (ret < 0) { _err("stdin pipe failed: %d\n", errno);  return; }
  ret = pipe(nsh_stdout); if (ret < 0) { _err("stdout pipe failed: %d\n", errno); return; }
  ret = pipe(nsh_stderr); if (ret < 0) { _err("stderr pipe failed: %d\n", errno); return; }

// Close default stdin, stdout and stderr
  close(0);
  close(1);
  close(2);

// Use the pipes as stdin, stdout and stderr
  #define READ_PIPE  0  // Read Pipes: stdin, stdout, stderr
  #define WRITE_PIPE 1  // Write Pipes: stdin, stdout, stderr
  dup2(nsh_stdin[READ_PIPE], 0);
  dup2(nsh_stdout[WRITE_PIPE], 1);
  dup2(nsh_stderr[WRITE_PIPE], 2);

// Create a new NSH Task using the pipes
  char *argv[] = { NULL };
  pid_t pid = task_create(
    "NSH Console",
    100,  // Priority
    CONFIG_DEFAULT_TASK_STACKSIZE,
    nsh_consolemain,
    argv
  );
  if (pid < 0) { _err("task_create failed: %d\n", errno); return; }
  _info("pid=%d\n", pid);

// Wait a while
  sleep(1);

// Send a few commands to NSH
  for (int i = 0; i < 5; i++) {

// Send a command to NSH stdin
    const char cmd[] = "ls\r";
    ret = write(
      nsh_stdin[WRITE_PIPE],
      cmd,
      sizeof(cmd)
    );
    _info("write nsh_stdin: %d\n", ret);

// Wait a while
    sleep(1);

// Read the output from NSH stdout.
    // TODO: This will block if there's nothing to read.
    static char buf[64];
    ret = read(
      nsh_stdout[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }

// Wait a while
    sleep(1);

#ifdef NOTUSED
    // Read the output from NSH stderr.
    // TODO: This will block if there's nothing to read.
    ret = read(    
      nsh_stderr[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }
#endif

}
}
```

And it works! Here's the NSH Task auto-running the `ls` Command received via our Pipe...

```text
NuttShell (NSH) NuttX-12.0.0
nsh> ls
/:
 dev/
 var/
nsh> est_terminal: write nsh_stdin: 9
test_terminal: read nsh_stdout: 63
test_terminal: K
...
nsh> ls
/:
 dev/
 var/
test_terminal: write nsh_stdin: 9
test_terminal: read nsh_stdout: 63
test_terminal: 
...
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/a9d67c135c458088946ed35c1b24be1b4aee3553/examples/lvgldemo/lvgldemo.c#L340-L390)

There's a problem with the code above... Calling `read()` on `nsh_stdout` will block if there's no NSH Output to be read.

Let's call `poll()` on `nsh_stdout` to check if there's NSH Output to be read...

## Poll for NSH Output

In the previous sections we started an NSH Shell that will execute NSH Commands that we pipe to it.

But there's a problem: Calling `read()` on `nsh_stdout` will block if there's no NSH Output to be read. And we can't block our LVGL App, since it needs to handle UI Events periodically.

Solution: We call `has_input` to check if there's NSH Output ready to be read, before reading the output: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L330-L353)

```c
  // Read the output from NSH stdout
  static char buf[64];
  if (has_input(nsh_stdout[READ_PIPE])) {
    ret = read(
      nsh_stdout[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }
  }

// Read the output from NSH stderr
  if (has_input(nsh_stderr[READ_PIPE])) {
    ret = read(    
      nsh_stderr[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }
  }
```

`has_input` calls `poll()` on `nsh_stdout` to check if there's NSH Output ready to be read: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L358-L397)

```c
// Return true if the File Descriptor has data to be read
static bool has_input(int fd) {

// Poll the File Descriptor for Input
  struct pollfd fdp;
  fdp.fd = fd;
  fdp.events = POLLIN;
  int ret = poll(
    (struct pollfd *)&fdp,  // File Descriptors
    1,  // Number of File Descriptors
    0   // Poll Timeout (Milliseconds)
  );

if (ret > 0) {
    // If Poll is OK and there is Input...
    if ((fdp.revents & POLLIN) != 0) {
      // Report that there's Input
      _info("has input: fd=%d\n", fd);
      return true;
    }

// Else report No Input
    _info("no input: fd=%d\n", fd);
    return false;

} else if (ret == 0) {
    // Ignore Timeout
    _info("timeout: fd=%d\n", fd);
    return false;

} else if (ret < 0) {
    // Handle Error
    _err("poll failed: %d, fd=%d\n", ret, fd);
    return false;
  }

// Never comes here
  DEBUGASSERT(false);
  return false;
}
```

`has_input` returns True if there's NSH Output waiting to be read...

```text
has_input: has input: fd=8
```

And `has_input` returns False (due to timeout) if there's nothing waiting to be read...

```text
has_input: timeout: fd=8
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L403-L556)

This polling needs to be done in an LVGL Timer, here's why...

## Timer for LVGL Terminal

In the previous sections we started an NSH Shell that will execute NSH Commands that we pipe to it.

Our LVGL Terminal for NSH Shell shall periodically check for output from the NSH Shell, and write the output to the LVGL Display...

-   Every couple of milliseconds...

-   We call `poll()` to check if NSH Shell has output data

-   We read the output from NSH Shell

-   We display the NSH Output in an LVGL Label Widget

We'll do this with an [LVGL Timer](https://docs.lvgl.io/master/overview/timer.html) like so: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/2f591f4e2589298caf6613ba409d667be61a9881/examples/lvgldemo/lvgldemo.c#L257-L269)

```c
// Create an LVGL Terminal that will let us interact with NuttX NSH Shell
void test_terminal(void) {

// Create an LVGL Timer to poll for output from NSH Shell
  static uint32_t user_data = 10;
  lv_timer_t *timer = lv_timer_create(
    my_timer,   // Callback
    5000,       // Timer Period (Milliseconds)
    &user_data  // Callback Data
  );
```

`my_timer` is our Timer Callback Function: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/2f591f4e2589298caf6613ba409d667be61a9881/examples/lvgldemo/lvgldemo.c#L350-L363)

```c
// Callback for LVGL Timer
void my_timer(lv_timer_t *timer) {

// Get the Callback Data
  uint32_t *user_data = timer->user_data;
  _info("my_timer called with callback data: %d\n", *user_data);
  *user_data += 1;

// TODO: Call poll() to check if NSH Stdout has output to be read

// TODO: Read the NSH Stdout

// TODO: Write the NSH Output to LVGL Label Widget
}
```

When we run this, LVGL calls our Timer Callback Function every 5 seconds...

```text
my_timer: my_timer called with callback data: 10
my_timer: my_timer called with callback data: 11
my_timer: my_timer called with callback data: 12
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/2f591f4e2589298caf6613ba409d667be61a9881/examples/lvgldemo/lvgldemo.c#L369-L436)

_Why poll for NSH Output? Why not run a Background Thread that will block on NSH Output?_

If we ran a Background Thread that will block until NSH Output is available, we still need to write the NSH Output to an LVGL Widget for display.

But LVGL is NOT Thread-Safe. Thus we need a Mutex to lock the LVGL Widgets, which gets messy.

For now, it's simpler to run an LVGL Timer to poll for NSH Output.

Let's add the polling to the LVGL Timer Callback...

## Poll for NSH Output in LVGL Timer

In the previous section we've created an LVGL Timer that's triggered periodically.

Inside the LVGL Timer Callback, let's poll the NSH Output and check if there's any output to be read: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L309-L356)

```c
// Callback for LVGL Timer
static void my_timer(lv_timer_t *timer) {
  ...
  // Read the output from NSH stdout
  static char buf[64];
  DEBUGASSERT(nsh_stdout[READ_PIPE] != 0);
  if (has_input(nsh_stdout[READ_PIPE])) {
    ret = read(
      nsh_stdout[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    _info("read nsh_stdout: %d\n", ret);
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }
  }

// Read the output from NSH stderr
  DEBUGASSERT(nsh_stderr[READ_PIPE] != 0);
  if (has_input(nsh_stderr[READ_PIPE])) {
    ret = read(    
      nsh_stderr[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    _info("read nsh_stderr: %d\n", ret);
    if (ret > 0) { buf[ret] = 0; _info("%s\n", buf); }
  }

// TODO: Write the NSH Output to LVGL Label Widget
```

NSH won't emit any output until we run some NSH Commands. So let's trigger some NSH Commands inside the LVGL Timer Callback: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L309-L356)

```c
// Callback for LVGL Timer
static void my_timer(lv_timer_t *timer) {

// Get the Callback Data
  uint32_t *user_data = timer->user_data;
  _info("my_timer called with callback data: %d\n", *user_data);
  *user_data += 1;

// Send a command to NSH stdin
  if (*user_data % 5 == 0) {
    const char cmd[] = "ls\r";
    DEBUGASSERT(nsh_stdin[WRITE_PIPE] != 0);
    ret = write(
      nsh_stdin[WRITE_PIPE],
      cmd,
      sizeof(cmd)
    );
    _info("write nsh_stdin: %d\n", ret);
  }
  
  // Read the output from NSH stdout
  ...
```

When we run this, we see the LVGL Timer Callback sending NSH Commands and printing the NSH Output...

```text
my_timer: my_timer called with callback data: 10
has_input: has input: fd=8
my_timer: read nsh_stdout: 63
my_timer: createWidgetsWrapped: start
createWidgetsWrapped: end
NuttShel
has_input: timeout: fd=10
my_timer: my_timer called with callback data: 11
has_input: has input: fd=8
my_timer: read nsh_stdout: 29
my_timer: l (NSH) NuttX-12.0.0
nsh> 
has_input: timeout: fd=10
my_timer: my_timer called with callback data: 12
has_input: timeout: fd=8
has_input: timeout: fd=10
my_timer: my_timer called with callback data: 13
has_input: timeout: fd=8
has_input: timeout: fd=10
my_timer: my_timer called with callback data: 14
my_timer: write nsh_stdin: 4
has_input: timeout: fd=8
has_input: timeout: fd=10
my_timer: my_timer called with callback data: 15
has_input: has input: fd=8
my_timer: read nsh_stdout: 33
my_timer: ls
/:
 dev/
 proc/
 var/
nsh> 
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/c30e1968d5106794f435882af69dfb7b1858d694/examples/lvgldemo/lvgldemo.c#L403-L556)

Now that our background processing is ready, let's render the LVGL Widgets for our terminal...

## Render Terminal with LVGL Widgets

Our LVGL Terminal will have 3 LVGL Widgets...

-   [LVGL Text Area Widget](https://docs.lvgl.io/master/widgets/textarea.html) that shows the NSH Output

(At the top)

-   [LVGL Text Area Widget](https://docs.lvgl.io/master/widgets/textarea.html) for NSH Input, to enter commands

(At the middle)

-   [LVGL Keyboard Widget](https://docs.lvgl.io/master/widgets/keyboard.html) for typing commands into NSH Input

(At the bottom)

![Set Default Font to Monospace](https://lupyuen.github.io/images/lvgl2-terminal2.jpg)

This is how we render the 3 LVGL Widgets: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/a37872d85c865557bee740cecd6adc35ae3197d2/examples/lvgldemo/lvgldemo.c#L374-L415)

```c
// PinePhone LCD Panel Width and Height (pixels)
#define PINEPHONE_LCD_PANEL_WIDTH  720
#define PINEPHONE_LCD_PANEL_HEIGHT 1440

// Margin of 10 pixels all around
#define TERMINAL_MARGIN 10

// Terminal Width is LCD Width minus Left and Right Margins
#define TERMINAL_WIDTH  (PINEPHONE_LCD_PANEL_WIDTH - 2 * TERMINAL_MARGIN)

// Keyboard is Lower Half of LCD.
// Terminal Height is Upper Half of LCD minus Top and Bottom Margins.
#define TERMINAL_HEIGHT ((PINEPHONE_LCD_PANEL_HEIGHT / 2) - 2 * TERMINAL_MARGIN)

// Height of Input Text Area
#define INPUT_HEIGHT 100

// Height of Output Text Area is Terminal Height minus Input Height minus Middle Margin
#define OUTPUT_HEIGHT (TERMINAL_HEIGHT - INPUT_HEIGHT - TERMINAL_MARGIN)

// Create the LVGL Widgets for the LVGL Terminal.
// Based on https://docs.lvgl.io/master/widgets/keyboard.html#keyboard-with-text-area
static void create_widgets(void) {

// Create an LVGL Keyboard Widget
  lv_obj_t *kb = lv_keyboard_create(lv_scr_act());

// Create an LVGL Text Area Widget for NSH Output
  output = lv_textarea_create(lv_scr_act());
  lv_obj_align(output, LV_ALIGN_TOP_LEFT, TERMINAL_MARGIN, TERMINAL_MARGIN);
  lv_textarea_set_placeholder_text(output, "Hello");
  lv_obj_set_size(output, TERMINAL_WIDTH, OUTPUT_HEIGHT);

// Create an LVGL Text Area Widget for NSH Input
  input = lv_textarea_create(lv_scr_act());
  lv_obj_align(input, LV_ALIGN_TOP_LEFT, TERMINAL_MARGIN, OUTPUT_HEIGHT + 2 * TERMINAL_MARGIN);
  lv_obj_add_event_cb(input, input_callback, LV_EVENT_ALL, kb);
  lv_obj_set_size(input, TERMINAL_WIDTH, INPUT_HEIGHT);

// Set the Keyboard to populate the NSH Input Text Area
  lv_keyboard_set_textarea(kb, input);
}
```

`input_callback` is the Callback Function for our LVGL Keyboard. Which we'll cover in a while.

Note that we're using the LVGL Default Font for all 3 LVGL Widgets. Which has a problem...

## Set LVGL Terminal Font to Monospace

Our LVGL Terminal looks nicer with a Monospace Font.

But watch what happens if we change the LVGL Default Font from Montserrat 20 (proportional) to UNSCII 16 (monospace)...

![Set Default Font to Monospace](https://lupyuen.github.io/images/lvgl2-terminal2.jpg)

The LVGL Keyboard has missing symbols! Enter, Backspace, ...

Thus we set the LVGL Default Font back to Montserrat 20.

And instead we set the Font Style for NSH Input and Output to UNSCII 16: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/58537ff2c0111e89c4bbe23a5683dc561fad6881/examples/lvgldemo/lvgldemo.c#L405-L422)

```c
  // Set the Font Style for NSH Input and Output to a Monospaced Font
  static lv_style_t terminal_style;
  lv_style_init(&terminal_style);
  lv_style_set_text_font(&terminal_style, &lv_font_unscii_16);

// Create an LVGL Text Area Widget for NSH Output
  output = lv_textarea_create(lv_scr_act());
  lv_obj_add_style(output, &terminal_style, 0);
  ...

// Create an LVGL Text Area Widget for NSH Input
  input = lv_textarea_create(lv_scr_act());
  lv_obj_add_style(input, &terminal_style, 0);
  ...
```

Now we see the LVGL Keyboard without missing symbols (pic below)...

-   [Watch the Demo on YouTube](https://www.youtube.com/watch?v=WdiXaMK8cNw)

Let's look at our Callback Function for the LVGL Keyboard...

![Set Terminal Font to Monospace](https://lupyuen.github.io/images/lvgl2-terminal3.jpg)

## Handle Input from LVGL Keyboard

Here's the Callback Function that handles input from the LVGL Keyboard.

It waits for the Enter key to be pressed, then it sends the typed command to NSH Shell via a POSIX Pipe: [lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/a37872d85c865557bee740cecd6adc35ae3197d2/examples/lvgldemo/lvgldemo.c#L417-L466)

```c
// Callback Function for NSH Input Text Area.
// Based on https://docs.lvgl.io/master/widgets/keyboard.html#keyboard-with-text-area
static void input_callback(lv_event_t *e) {
  int ret;

// Decode the LVGL Event
  const lv_event_code_t code = lv_event_get_code(e);

// If Enter has been pressed, send the Command to NSH Input
  if (code == LV_EVENT_VALUE_CHANGED) {

// Get the Keyboard Widget from the LVGL Event
    const lv_obj_t *kb = lv_event_get_user_data(e);
    DEBUGASSERT(kb != NULL);

// Get the Button Index of the Keyboard Button Pressed
    const uint16_t id = lv_keyboard_get_selected_btn(kb);

// Get the Text of the Keyboard Button
    const char *key = lv_keyboard_get_btn_text(kb, id);
    if (key == NULL) { return; }

// If Enter is pressed...
    if (key[0] == 0xef && key[1] == 0xa2 && key[2] == 0xa2) {

// Read the NSH Input
      DEBUGASSERT(input != NULL);
      const char *cmd = lv_textarea_get_text(input);
      if (cmd == NULL || cmd[0] == 0) { return; }

// Send the Command to NSH stdin
      DEBUGASSERT(nsh_stdin[WRITE_PIPE] != 0);
      ret = write(
        nsh_stdin[WRITE_PIPE],
        cmd,
        strlen(cmd)
      );

// Erase the NSH Input
      lv_textarea_set_text(input, "");
    }
  }
}
```

The command runs in NSH Shell and produces NSH Output. Which is handled by the LVGL Timer Callback Function...

## Handle Output from NSH Shell

Our LVGL Timer Callback Function checks periodically whether there's any NSH Output waiting to be processed.

If there's NSH Output, the Callback Function writes the output to the NSH Output Text Area:
[lvgldemo.c](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/a37872d85c865557bee740cecd6adc35ae3197d2/examples/lvgldemo/lvgldemo.c#L320-L372)

```c
// Callback Function for LVGL Timer.
// Based on https://docs.lvgl.io/master/overview/timer.html#create-a-timer
static void timer_callback(lv_timer_t *timer) {

// Read the output from NSH stdout
  static char buf[64];
  DEBUGASSERT(nsh_stdout[READ_PIPE] != 0);
  if (has_input(nsh_stdout[READ_PIPE])) {
    ret = read(
      nsh_stdout[READ_PIPE],
      buf,
      sizeof(buf) - 1
    );
    if (ret > 0) {
      // Add to NSH Output Text Area
      buf[ret] = 0;
      remove_escape_codes(buf, ret);
      DEBUGASSERT(output != NULL);
      lv_textarea_add_text(output, buf);
    }
  }
```

`remove_escape_codes` searches for Escape Codes in the NSH Output and replaces them by spaces.

That's why we see 3 spaces between the `nsh>` prompt and the NSH Command. (Pic below)

For more details, check out the article...

-   ["NuttX RTOS for PinePhone: LVGL Terminal for NSH Shell"](https://lupyuen.github.io/articles/terminal)

![3 spaces between the `nsh>` prompt and the NSH Command](https://lupyuen.github.io/images/lvgl2-terminal3.jpg)

# PinePhone on NuttX becomes a Feature Phone

_Now that NuttX can run Touchscreen Apps on PinePhone... What next?_

Maybe we can turn NuttX on PinePhone into a __Feature Phone__?

Just __Voice Calls and SMS__, using PinePhone's LTE Modem.

_This is useful because...?_

So we can pop a microSD Card (and SIM) into any PinePhone...

And turn it instantly into an __Emergency Phone__?

_What NuttX Drivers would we need?_

We need a NuttX Driver for the PinePhone's __Quectel LTE Modem__.

Which talks over USB Serial. Thus we also need a NuttX Driver for PinePhone's __Allwinner A64 USB Controller__.

More about this in the next section.

_And if there's no LTE Network Coverage? Like in a Natural Disaster?_

The Long-Range, Low-Power __LoRa Network__ might be good for search and rescue communications.

(Short Text Messages only plus GPS Geolocation, non-guaranteed message delivery)

Just attach the LoRa Case to PinePhone...

-   [PineDio LoRa Add-On Case](https://pine64.com/product/pinephone-pinephone-pro-pindio-lora-add-on-case/)

(Still in stock!)

We might use JF's Driver...

-   [JF002/pinedio-lora-driver](https://codeberg.org/JF002/pinedio-lora-driver)

Or the LoRa Driver that we have ported to NuttX...

-   ["LoRa SX1262 on Apache NuttX RTOS"](https://lupyuen.github.io/articles/sx1262)

Or maybe Meshtastic (with Portduino), since it has a complete LoRa Messaging App...

-   [Meshtastic](https://meshtastic.org/)

-   [Portduino](https://github.com/geeksville/framework-portduino)

_Will PinePhone on NuttX become a fully-functional smartphone?_

Maybe someday? We're still lacking plenty of drivers: WiFi, Bluetooth LE, GPS, Audio, ...

Probably better to start as a Feature Phone (or LoRa Communication) and build up.

# USB Driver and LTE Modem Driver for PinePhone

Read the articles...

-   ["NuttX RTOS for PinePhone: Exploring USB"](https://lupyuen.github.io/articles/usb2)

-   ["NuttX RTOS for PinePhone: Simpler USB with EHCI (Enhanced Host Controller Interface)"](https://lupyuen.github.io/articles/usb3)

-   ["NuttX RTOS for PinePhone: 4G LTE Modem"](https://lupyuen.github.io/articles/lte)

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

_What NuttX Drivers would we need to turn PinePhone into a Feature Phone? (Voice Calls and SMS only)_

We need a NuttX Driver for the PinePhone's __Quectel LTE Modem__...

![Quectel LTE Modem in PinePhone](https://lupyuen.github.io/images/usb2-title.jpg)

Which talks over USB Serial. Thus we also need a NuttX Driver for PinePhone's __Allwinner A64 USB Controller__.

Here are the docs for Allwinner A64 USB Controller...

-   [Allwinner A64 User Manual](https://github.com/lupyuen/pinephone-nuttx/releases/download/doc/Allwinner_A64_User_Manual_V1.1.pdf), Section 7.5 "USB" (Page 583)

-   [Allwinner A20 User Manual](https://github.com/allwinner-zh/documents/raw/master/A20/A20_User_Manual_v1.4_20150510.pdf), Section 6.7 "USB DRD" (Page 682), Section 6.8 "USB Host" (Page 683)

-   [Allwinner USB OTG Controller Register Guide](https://linux-sunxi.org/USB_OTG_Controller_Register_Guide)

-   [Mentor Graphics MUSBMHDRC USB 2.0 Multi-Point Dual-Role Controller: Product Specification and Programming Guide](https://linux-sunxi.org/images/7/73/Musbmhdrc.pdf)

_Any sample code for Allwinner A64 USB?_

Refer to the Allwinner A64 USB Drivers in FreeBSD and NetBSD...

-   [freebsd/sys/dev/usb/controller/musb_otg_allwinner.c](https://github.com/freebsd/freebsd-src/blob/main/sys/dev/usb/controller/musb_otg_allwinner.c#L95)

[freebsd/sys/dev/usb/controller/musb_otg.c](https://github.com/freebsd/freebsd-src/blob/main/sys/dev/usb/controller/musb_otg.c)

[freebsd/sys/arm/allwinner/aw_usbphy.c](https://github.com/freebsd/freebsd-src/blob/main/sys/arm/allwinner/aw_usbphy.c#L135)

-   [NetBSD/sys/arch/arm/sunxi/sunxi_musb.c](https://github.com/NetBSD/src/blob/trunk/sys/arch/arm/sunxi/sunxi_musb.c#L67)

[NetBSD/sys/arch/arm/sunxi/sunxi_usbphy.c](https://github.com/NetBSD/src/blob/trunk/sys/arch/arm/sunxi/sunxi_usbphy.c#L95)

_But Allwinner A64's Official Docs are horrigibly lacking..._

Maybe we refer to the [NXP i.MX 8 USB Docs](https://www.nxp.com/webapp/Download?colCode=IMX8MDQLQRM), and we compare with the FreeBSD / NetBSD USB Drivers for i.MX 8?

(Since NXP i.MX 8 is so much better documented than Allwinner A64)

_How do USB Drivers work in NuttX?_

Check out this NuttX Doc on USB Drivers...

-   ["USB Host-Side Drivers"](https://nuttx.apache.org/docs/latest/components/drivers/special/usbhost.html)

And the NuttX USB Driver for STM32...

-   [stm32_otgfshost.c](https://github.com/apache/nuttx/blob/master/arch/arm/src/stm32/stm32_otgfshost.c)

-   [stm32_otgfsdev.c](https://github.com/apache/nuttx/blob/master/arch/arm/src/stm32/stm32_otgfsdev.c)

-   [stm32_usbfs.c](https://github.com/apache/nuttx/blob/master/arch/arm/src/stm32/stm32_usbfs.c)

-   [stm32_usbhost.c](https://github.com/apache/nuttx/blob/master/arch/arm/src/stm32/stm32_usbhost.c)

(USB OTG FS: Able to act as a device/host/OTG peripheral, at full speed 12Mbps)

(USB OTG HS: Able to act as a device/host/OTG peripheral, at full speed 12Mbps or high speed 480Mbps)

_How did we get the FreeBSD and NetBSD USB Drivers for Allwinner A64?_

PinePhone's Device Tree says that the USB Drivers are...

```text
usb@1c19000 {
  compatible = "allwinner,sun8i-a33-musb";
  ...
phy@1c19400 {
  compatible = "allwinner,sun50i-a64-usb-phy";
```

So we searched for `allwinner,sun8i-a33-musb` and `allwinner,sun50i-a64-usb-phy`.

Here's the PinePhone USB Device Tree: [sun50i-a64-pinephone-1.2.dts](https://github.com/lupyuen/pinephone-nuttx/blob/main/sun50i-a64-pinephone-1.2.dts#L647-L721)

```text
usb@1c19000 {
  compatible = "allwinner,sun8i-a33-musb";
  reg = <0x1c19000 0x400>;
  clocks = <0x02 0x29>;
  resets = <0x02 0x12>;
  interrupts = <0x00 0x47 0x04>;
  interrupt-names = "mc";
  phys = <0x31 0x00>;
  phy-names = "usb";
  extcon = <0x31 0x00>;
  dr_mode = "otg";
  status = "okay";
};

phy@1c19400 {
  compatible = "allwinner,sun50i-a64-usb-phy";
  reg = <0x1c19400 0x14 0x1c1a800 0x04 0x1c1b800 0x04>;
  reg-names = "phy_ctrl\0pmu0\0pmu1";
  clocks = <0x02 0x56 0x02 0x57>;
  clock-names = "usb0_phy\0usb1_phy";
  resets = <0x02 0x00 0x02 0x01>;
  reset-names = "usb0_reset\0usb1_reset";
  status = "okay";
  #phy-cells = <0x01>;
  usb-role-switch;
  phandle = <0x31>;

port {

endpoint {
      remote-endpoint = <0x32>;
      phandle = <0x47>;
    };
  };
};

usb@1c1a000 {
  compatible = "allwinner,sun50i-a64-ehci\0generic-ehci";
  reg = <0x1c1a000 0x100>;
  interrupts = <0x00 0x48 0x04>;
  clocks = <0x02 0x2c 0x02 0x2a 0x02 0x5b>;
  resets = <0x02 0x15 0x02 0x13>;
  status = "okay";
};

usb@1c1a400 {
  compatible = "allwinner,sun50i-a64-ohci\0generic-ohci";
  reg = <0x1c1a400 0x100>;
  interrupts = <0x00 0x49 0x04>;
  clocks = <0x02 0x2c 0x02 0x5b>;
  resets = <0x02 0x15>;
  status = "okay";
};

usb@1c1b000 {
  compatible = "allwinner,sun50i-a64-ehci\0generic-ehci";
  reg = <0x1c1b000 0x100>;
  interrupts = <0x00 0x4a 0x04>;
  clocks = <0x02 0x2d 0x02 0x2b 0x02 0x5d>;
  resets = <0x02 0x16 0x02 0x14>;
  phys = <0x31 0x01>;
  phy-names = "usb";
  status = "okay";
};

usb@1c1b400 {
  compatible = "allwinner,sun50i-a64-ohci\0generic-ohci";
  reg = <0x1c1b400 0x100>;
  interrupts = <0x00 0x4b 0x04>;
  clocks = <0x02 0x2d 0x02 0x5d>;
  resets = <0x02 0x16>;
  phys = <0x31 0x01>;
  phy-names = "usb";
  status = "okay";
};
```

# 4G LTE Modem

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

We're now upstreaming the driver for 4G LTE Modem to NuttX Mainline...

-   [arm64/pinephone: Add driver for PinePhone LTE Modem (Quectel EG25-G)](https://github.com/apache/nuttx/pull/9304)

TODO: Disable UART2 and /dev/ttyS2 so that UART3 maps neatly to /dev/ttyS3. [(See this)](https://github.com/apache/nuttx/pull/9304#discussion_r1195862416)

This is how we make a Phone Call and send a Text Message...

## Outgoing Phone Call

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

This is the NuttX App that makes a Phone Call on PinePhone: [dial_number](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L343-L432)

Here's the output...

```text
NuttShell (NSH) NuttX-12.0.3
nsh> hello

// Check Modem Status
Command: AT
Response:
RDY
+CFUN: 1
+CPIN: READY
+QUSIM: 1
+QIND: SMS DONE
// SIM and SMS are ready

// Check Network Status
Command: AT+CREG?
Response:
+CREG: 0,1
+QIND: PB DONE
// Network and Phonebook are ready

// Get Network Operator
Command: AT+COPS?
Response: +COPS: 0,0,"SGP-M1",7

// Get Range of PCM Parameters for Digital Audio
Command: AT+QDAI=?
Response: +QDAI: (1-4),(0,1),(0,1),(0-5),(0-2),(0,1)(1)(1-16)

// Get Current PCM Configuration for Digital Audio
Command: AT+QDAI?
Response: +QDAI: 1,1,0,1,0,0,1,1

// Make Outgoing Phone Call
Command: ATDyourphonenumber;
Response:
OK

// Receiver has hung up
Response:
NO CARRIER

// Hang up Phone Call
Command: ATH
Response: OK
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L562-L737)

_What does this say: `+QDAI: 1,1,0,1,0,0,1,1`_

The above __PCM Digital Audio Configuration__ for the LTE Modem says...

- __io = 1__

Digital PCM Output

- __mode = 1__

Slave Mode

- __fsync = 0__

Primary Mode (short-synchronization)

- __clock = 1__

Clock Frequency is 256 kHz

- __format = 0__

Data Format is 16-bit linear

- __sample = 0__

Sampling Rate is 8 kHz

- __num_slots = 1__

Number of Slot is 1

- __slot_mapping = 1__

Slot Mapping Value is 1

## Send SMS in Text Mode

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

This is how we send an SMS in Text Mode: [send_sms_text](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L162-L253)

Here's the log...

```text
// Set Message Format to Text Mode
Command: AT+CMGF=1
Response: OK

// Set Character Set to GSM
Command: AT+CSCS="GSM"
Response: OK

// Send an SMS to the Phone Number.
// yourphonenumber looks like +1234567890
// Works without country code, like 234567890
Command:
AT+CMGS="yourphonenumber"

// We wait for Modem to respond with ">"
Response:
>

// SMS Message in Text Format, terminate with Ctrl-Z
Command:
Hello from Apache NuttX RTOS on PinePhone! (SMS Text Mode)<Ctrl-Z>

// Modem sends the SMS Message
Response:
+CMGS: 13
OK
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L622-L659)

_Why do we get Error 350 sometimes? (Rejected by SMSC)_

```text
+CMS ERROR: 350
```

Check with the telco. I got this error when the telco blocked my outgoing SMS messages.

## Send SMS in PDU Mode

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

Now we send an SMS Message in PDU Mode. Based on...

- [Quectel GSM AT Commands Application Note](https://www.cika.com/soporte/Information/GSMmodules/Quectel/AppNotes/Quectel_GSM_ATC_Application_Note.pdf), Section 9.3.2 "Send SMS in PDU mode", Page 26

- [ETSI GSM 07.05 Spec](https://www.etsi.org/deliver/etsi_gts/07/0705/05.01.00_60/gsmts_0705v050100p.pdf) (AT Commands)

- [ETSI GSM 03.40 Spec](https://en.wikipedia.org/wiki/GSM_03.40) (PDU Format)

This is how we send an SMS in PDU Mode: [send_sms_pdu](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L255-L341)

Suppose we're sending an SMS to this Phone Number (International Format)...

```text
#define PHONE_NUMBER    "+1234567890"
#define PHONE_NUMBER_PDU "2143658709"
```

Note that we flip the nibbles (half-bytes) from the Original Phone Number to produce the PDU Phone Number.

If the number of nibbles (half-bytes) is odd, insert "F" into the PDU Phone Number like this...

```text
#define PHONE_NUMBER    "+123456789"
#define PHONE_NUMBER_PDU "214365870F9"
```

Assuming there are 10 decimal digits in our Phone Number "+1234567890", here's the AT Command...

```text
// Send SMS Command
const char cmd[] = 
  "AT+CMGS="
  "41"  // TODO: PDU Length in bytes, excluding the Length of SMSC
  "\r";
```

(We'll talk about PDU Length in a while)

And here's the SMS Message PDU that we'll send in the AT Command...

```text
// SMS Message in PDU Format
const char cmd[] = 
  "00"  // Length of SMSC information (None)
  "11"  // SMS-SUBMIT message
  "00"  // TP-Message-Reference: 00 to let the phone set the message reference number itself
  "0A"  // TODO: Address-Length: Length of phone number (Number of Decimal Digits in Phone Number)
  "91"  // Type-of-Address: 91 for International Format of phone number
  PHONE_NUMBER_PDU  // TODO: Phone Number in PDU Format
  "00"  // TP-PID: Protocol identifier
  "08"  // TP-DCS: Data coding scheme
  "01"  // TP-Validity-Period
  "1C"  // TP-User-Data-Length: Length of Encoded Message Text in bytes
  // TP-User-Data: Encoded Message Text "Hello,Quectel!"
  "00480065006C006C006F002C005100750065006300740065006C0021"
  "\x1A";  // End of Message (Ctrl-Z)
```

(We'll talk about Encoded Message Text in a while)

(Remember to update "Address-Length" according to your phone number)

Here's the log...

```text
// Set Message Format to PDU Mode
Command: AT+CMGF=0
Response: OK

// Send an SMS with 41 bytes (excluding SMSC)
Command: AT+CMGS=41

// We wait for Modem to respond with ">"
Response: >

// SMS Message in PDU Format, terminate with Ctrl-Z.
// yourphonenumberpdu looks like 2143658709, which represents +1234567890
// Country Code is mandatory. Remember to insert "F" for odd number of nibbles.
Command:
0011000A91yourphonenumberpdu0008011C00480065006C006C006F002C005100750065006300740065006C0021<Ctrl-Z>

// Modem sends the SMS Message
Response: 
+CMGS: 14
OK
```

[(See the Complete Log)](https://github.com/lupyuen2/wip-pinephone-nuttx-apps/blob/8ea4208cbd4758a0f1443c61bffa7ec4a8390695/examples/hello/hello_main.c#L663-L681)

Let's talk about the SMS PDU...

## SMS PDU Format

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

_What's the PDU Length?_

Our SMS Message PDU has 42 total bytes...

```text
"00"  // Length of SMSC information (None)
"11"  // SMS-SUBMIT message
"00"  // TP-Message-Reference: 00 to let the phone set the message reference number itself
"0A"  // TODO: Address-Length: Length of phone number (Assume 10  Decimal Digits in Phone Number)
"91"  // Type-of-Address: 91 for International Format of phone number
PHONE_NUMBER_PDU  // TODO: Assume 5 bytes in PDU Phone Number (10 Decimal Digits)
"00"  // TP-PID: Protocol identifier
"08"  // TP-DCS: Data coding scheme
"01"  // TP-Validity-Period
"1C"  // TP-User-Data-Length: Length of Encoded Message Text in bytes
// TP-User-Data: Assume 28 bytes in Encoded Message Text
"00480065006C006C006F002C005100750065006300740065006C0021"
```

PDU Length excludes the SMSC Information (First Byte).

Thus our PDU Length is 41 bytes...

```text
// Send SMS Command
const char cmd[] = 
  "AT+CMGS="
  "41"  // TODO: PDU Length in bytes, excluding the Length of SMSC
  "\r";
```

Remember to update the PDU Length according to your phone number and message text.

_What do the fields mean?_

```text
"00"  // Length of SMSC information (None)
"11"  // SMS-SUBMIT message
"00"  // TP-Message-Reference: 00 to let the phone set the message reference number itself
"0A"  // TODO: Address-Length: Length of phone number (Assume 10 Decimal Digits in Phone Number)
"91"  // Type-of-Address: 91 for International Format of phone number
PHONE_NUMBER_PDU  // TODO: Assume 5 bytes in PDU Phone Number (10 Decimal Digits)
"00"  // TP-PID: Protocol identifier
"08"  // TP-DCS: Data coding scheme
"01"  // TP-Validity-Period
"1C"  // TP-User-Data-Length: Length of Encoded Message Text in bytes
// TP-User-Data: Assume 28 bytes in Encoded Message Text
"00480065006C006C006F002C005100750065006300740065006C0021"
```

- Length of SMSC information: "00"

We use the default SMS Centre (SMSC), so the SMSC Info Length is 0.

- SM-TL (Short Message Transfer Protocol) TPDU (Transfer Protocol Data Unit) is SMS-SUBMIT Message: "11"

[(GSM 03.40, TPDU Fields)](https://en.wikipedia.org/wiki/GSM_03.40#TPDU_Fields)

TP-Message-Type-Indicator (TP-MTI, Bits 0 and 1) is `0b01` (SMS-SUBMIT):

- Submit a message to SMSC for transmission.

[(GSM 03.40, TPDU Types)](https://en.wikipedia.org/wiki/GSM_03.40#TPDU_Types)

TP-Validity-Period-Format (TP-VPF, Bits 3 and 4) is `0b10` (Relative Format):

- Message Validity Period is in Relative Format.
  
    [(GSM 03.40, Validity Period)](https://en.wikipedia.org/wiki/GSM_03.40#Validity_Period)

Value of Message Validity Period is in TP-Validity-Period below.
 
- TP-Message-Reference (TP-MR): "00"

"00" will let the phone generate the Message Reference Number itself

[(GSM 03.40, Message Reference)](https://en.wikipedia.org/wiki/GSM_03.40#Message_Reference)

- Address-Length: "0A"

Length of phone number (Number of Decimal Digits in Phone Number, excluding "F")

[(GSM 03.40, Addresses)](https://en.wikipedia.org/wiki/GSM_03.40#Addresses)

- Type-of-Address: "91"

91 for International Format of phone number

Numbering Plan Identification (NPI, Bits 0 to 3) = `0b0001` (ISDN / Telephone Numbering Plan)

Type Of Number (TON, Bits 4 to 6) = `0b001` (International Number)

EXT (Bit 7) = `1` (No Extension)

[(GSM 03.40, Addresses)](https://en.wikipedia.org/wiki/GSM_03.40#Addresses)

- PHONE_NUMBER_PDU: Phone Number in PDU Format (nibbles swapped)

Remember to insert "F" for odd number of nibbles...

```text
  #define PHONE_NUMBER    "+123456789"
  #define PHONE_NUMBER_PDU "214365870F9"
  ```

[(GSM 03.40, Address Examples)](https://en.wikipedia.org/wiki/GSM_03.40#Address_examples)

- TP-Protocol-Identifier (TP-PID): "00"

Default Store-and-Forward Short Message

[(GSM 03.40, Protocol Identifier)](https://en.wikipedia.org/wiki/GSM_03.40#Protocol_Identifier)

- TP-Data-Coding-Scheme (TP-DCS): "08"

Message Text is encoded with UCS2 Character Set

[(GSM 03.40, Data Coding Scheme)](https://en.wikipedia.org/wiki/GSM_03.40#Data_Coding_Scheme)

[(SMS Data Coding Scheme)](https://en.wikipedia.org/wiki/Data_Coding_Scheme#SMS_data_coding_scheme)

- TP-Validity-Period (TP-VP): "01"

Message is valid for 10 minutes, relative to current time:

(`"01"` + 1) x 5 minutes

[(GSM 03.40, Validity Period)](https://en.wikipedia.org/wiki/GSM_03.40#Validity_Period)

(See TP-Validity-Period-Format above)

- TP-User-Data-Length (TP-UDL): "1C"

Length of Encoded Message Text in bytes

[(GSM 03.40, Message Content)](https://en.wikipedia.org/wiki/GSM_03.40#Message_Content)

- TP-User-Data (TP-UD): Encoded Message Text

Message Text is encoded with UCS2 Character Set

(Because of TP-Data-Coding-Scheme above)

[(GSM 03.40, Message Content)](https://en.wikipedia.org/wiki/GSM_03.40#Message_Content)

_How do we encode the Message Text?_

From above we see that the Message Text is encoded with UCS2 Character Set...

- TP-Data-Coding-Scheme (TP-DCS): "08"

Message Text is encoded in UCS2 Character Set

[(GSM 03.40, Data Coding Scheme)](https://en.wikipedia.org/wiki/GSM_03.40#Data_Coding_Scheme)

[(SMS Data Coding Scheme)](https://en.wikipedia.org/wiki/Data_Coding_Scheme#SMS_data_coding_scheme)

The UCS2 Encoding is actually [Unicode UTF-16](https://en.wikipedia.org/wiki/UTF-16)...

> "the SMS standard specifies UCS-2, but almost all users actually implement UTF-16 so that emojis work"

[(Source)](https://en.wikipedia.org/wiki/UTF-16)

So this Encoded Message Text...

```text
// TP-User-Data: Message Text encoded with UCS2 Character Set
"00480065006C006C006F002C005100750065006300740065006C0021"
```

Comes from the [Unicode UTF-16 Encoding](https://en.wikipedia.org/wiki/UTF-16) of the Message Text "Hello,Quectel!"...

| Character | UTF-16 Encoding |
|:---------:|:---------------:|
| `H` | `0048`
| `e` | `0065`
| `l` | `006C`
| `l` | `006C`
| `o` | `006F`
| `,` | `002C`
| `Q` | `0051`
| `u` | `0075`
| `e` | `0065`
| `c` | `0063`
| `t` | `0074`
| `e` | `0065`
| `l` | `006C`
| `!` | `0021`

(These are 7-Bit ASCII Characters, so the UTF-16 Encoding looks identical to ASCII)

## SMS Text Mode vs PDU Mode

Read the article...

-   ["NuttX RTOS for PinePhone: Phone Calls and Text Messages"](https://lupyuen.github.io/articles/lte2)

_Why send SMS in PDU Mode instead of Text Mode?_

Sending SMS Messages in Text Mode looks easier. But we __should use PDU Mode__ instead. Here's why...

__In Text Mode:__ This is how we send an SMS...

```text
// Text Mode: How many characters in this SMS?
AT+CMGS="+1234567890"
```

__In PDU Mode:__ We do it like so...

```text
// PDU Mode: 41 bytes in this SMS (excluding SMSC)
AT+CMGS=41
```

See the difference? __PDU Mode is more precise__ because we state exactly how many bytes there are in the SMS.

With Text Mode, there's a risk of garbled messages when characters are dropped during UART Transmission. (Which happens!)

_But what if characters are dropped in PDU Mode?_

The LTE Modem will say it's an __Invalid PDU__...

```text
+CMS ERROR: 304
```

Our app should catch this error and resend.

# PinePhone Accelerometer and Gyroscope

To read PinePhone's InvenSense MPU-6050 Accelerometer and Gyroscope, check out this article...

-   ["Inside a Smartphone Accelerometer: PinePhone with NuttX RTOS"](https://www.hackster.io/lupyuen/inside-a-smartphone-accelerometer-pinephone-with-nuttx-rtos-b92b58)

# Compile NuttX on Android with Termux

_Can we compile NuttX on an Android Phone (or Tablet) with Termux?_

That would be really cool for checking whether the Latest NuttX Updates are building OK for our target device... All we need is an Android Phone!

We managed to install the NuttX Build Tools on Android Termux (including `kconfig`)...

-   ["Compile Apache NuttX RTOS on Android with Termux"](https://gist.github.com/lupyuen/f59c681dde9ebac86b331f2577aa04ad)

NuttX `make` starts OK, but it fails later because we couldn't build the GCC Arm64 Toolchain on Android Termux.

# Emulate PinePhone with Unicorn Emulator

_To make PinePhone testing easier..._

_Can we emulate Arm64 PinePhone with [Unicorn Emulator](https://www.unicorn-engine.org/)?_

Read the articles...

-   ["(Possibly) Emulate PinePhone with Unicorn Emulator"](https://lupyuen.github.io/articles/unicorn)

-   ["(Clickable) Call Graph for Apache NuttX Real-Time Operating System"](https://lupyuen.github.io/articles/unicorn2)

![Emulate Arm64 Machine Code](https://lupyuen.github.io/images/unicorn-code.png)

# Simulate PinePhone UI with Zig, LVGL and WebAssembly

Read the articles...

-   ["NuttX RTOS for PinePhone: Feature Phone UI in LVGL, Zig and WebAssembly"](https://lupyuen.github.io/articles/lvgl4)

-   ["(Possibly) LVGL in WebAssembly with Zig Compiler"](https://lupyuen.github.io/articles/lvgl3)

We're now building a __Feature Phone UI__ for NuttX on PinePhone...

Can we simulate the Feature Phone UI with __Zig, LVGL and WebAssembly__ in a Web Browser? To make the UI Coding a little easier?

We have previously created a simple __LVGL App with Zig__ for PinePhone...

- [pinephone-lvgl-zig](https://github.com/lupyuen/pinephone-lvgl-zig)

Zig natively supports __WebAssembly__...

- [WebAssembly on Zig](https://ziglang.org/documentation/master/#WebAssembly)

So we might run __Zig + JavaScript__ in a Web Browser like so...

- [WebAssembly With Zig in a Web Browser](https://dev.to/sleibrock/webassembly-with-zig-pt-ii-ei7)

But LVGL doesn't work with JavaScript yet. LVGL runs in a Web Browser by compiling with Emscripten and SDL...

- [LVGL with Emscripten and SDL](https://github.com/lvgl/lv_web_emscripten)

Therefore we shall do this...

1.  Use Zig to compile LVGL from C to WebAssembly [(With `zig cc`)](https://github.com/lupyuen/zig-bl602-nuttx#zig-compiler-as-drop-in-replacement-for-gcc)

1.  Use Zig to connect the JavaScript UI (canvas rendering + input events) to LVGL WebAssembly [(Like this)](https://dev.to/sleibrock/webassembly-with-zig-pt-ii-ei7)

Check out the updates here...

- ["Simulate PinePhone UI with Zig, LVGL and WebAssembly"](https://github.com/lupyuen/pinephone-lvgl-zig#simulate-pinephone-ui-with-zig-lvgl-and-webassembly)

# Apache NuttX RTOS for PinePhone Pro

TODO: [WIP port of NuttX to PinePhone Pro](https://github.com/apache/nuttx/pull/10193)

(1) Would be good to provide the __Arm64 Disassembly__.

(So that I can locate the addresses, also peek at the code snippets)

```bash
## Dump the disassembly to nuttx.S
aarch64-none-elf-objdump \
  -t -S --demangle --line-numbers --wide \
  nuttx \
  >nuttx.S \
  2>&1
```

(2) What's the __Boot Address kernel_addr_r__ for PinePhone Pro?

I can't find it in the docs, so I assume that this value is correct:

```c
/* U-Boot loads NuttX at this address (kernel_addr_r) */
#define CONFIG_LOAD_BASE          0x02080000
```

Here's how we get kernel_addr_r from U-Boot (is it the same for Tow-Boot?):

https://lupyuen.github.io/articles/uboot#boot-address

(3) Change the __Memory Map (RAM and I/O)__ to this, based on the Address Mapping from RK3399 Tech Ref Manual (Part 1) Page 560:

https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h#L45-L51

```c
// RAM Base Address: I'm guessing this based on CONFIG_LOAD_BASE (kernel_addr_r)
#define CONFIG_RAMBANK1_ADDR      0x02000000
// RAM Size: Let's keep this for now, we'll expand later
#define CONFIG_RAMBANK1_SIZE      MB(512)
// I/O Addresses begin at F800_0000
#define CONFIG_DEVICEIO_BASEADDR  0xF8000000
// Up to FFFF_FFFF
#define CONFIG_DEVICEIO_SIZE      MB(128)
```

(4) __Arm64 Generic Interrupt Controller (GIC)__ is Version 3 (instead of PinePhone's Version 2)

According to RK3399 Tech Ref Manual (Part 1) Page 560, RK3399 uses GIC-500, which is based on GIC v3. (PinePhone uses GIC v2)

To change GIC from v2 to v3:

```bash
make menuconfig
## Go to System Type > GIC version
## Change from 2 to 3
## Save and exit menuconfig

## Verify that GIC version is now 3:
grep ARM_GIC_VERSION .config
```

More about GIC: https://lupyuen.github.io/articles/interrupt#generic-interrupt-controller

More about ARM_GIC_VERSION: https://github.com/apache/nuttx/blob/master/arch/arm64/Kconfig#L200-L209

(5) Next we need to fill in the __GIC Base Address__:

https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/chip.h

```c
/* Allwinner A64 Generic Interrupt Controller v2: Distributor and Redist */
#define CONFIG_GICD_BASE          0x1C81000
#define CONFIG_GICR_BASE          0x1C82000
```

But GIC v3 requires an additional field CONFIG_GICR_OFFSET, like this code from NuttX QEMU:

https://github.com/apache/nuttx/blob/master/arch/arm64/include/qemu/chip.h#L47-L51

```c
#define CONFIG_GICD_BASE          0x8000000
#define CONFIG_GICR_BASE          0x80a0000
#define CONFIG_GICR_OFFSET        0x20000
```

According to the [Linux Device Tree for RK3399](https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3399.dtsi#L549-L553):
- GICD = 0xfee00000
- GICR = 0xfef00000

But I'm not sure what's [CONFIG_GICR_OFFSET](https://github.com/apache/nuttx/blob/master/arch/arm64/src/common/arm64_gicv3.c#L786-L793). (Offset to the GIC Registers for each CPU?)

Maybe we stick with the current value and test whether [UART Interrupts](https://lupyuen.github.io/articles/serial#uart-with-interrupts) are OK?

[(See the Linux doc for GIC)](https://www.kernel.org/doc/Documentation/devicetree/bindings/interrupt-controller/arm%2Cgic-v3.txt)

RK3399 UART0 is at [GIC Shared Peripheral Interrupt 99](https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3399.dtsi#L695-L706)

RK3399 UART is a [DesignWare APB UART (dw-apb-uart)](https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3399.dtsi#L696), which maps to the [Linux DesignWare 8250 Driver (8250_dw.c)](https://github.com/torvalds/linux/blob/master/drivers/tty/serial/8250/8250_dw.c#L804).

Which is compatible with the [NuttX 16550 UART Driver](https://lupyuen.github.io/articles/plic#appendix-fix-the-spurious-uart-interrupts). So remember to enable 16550_WAIT_LCR, and set 16550_REGINCR=4. [(Because regshift=2)](https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/rockchip/rk3399.dtsi#L701)

The IRQs (Interrupt IDs) might need to change:

https://github.com/apache/nuttx/blob/master/arch/arm64/include/a64/irq.h

This should follow RK3399 Tech Ref Manual (Part 1) Page 15.

Eventually the I/O Peripherals will have completely different addresses too:

https://github.com/apache/nuttx/blob/master/arch/arm64/src/a64/hardware/a64_memorymap.h

TODO

# Test Logs

This section contains PinePhone NuttX Logs captured from various tests...

## USB Devices on PinePhone

We captured this log of USB Devices on PinePhone, which will be helpful when we build the NuttX USB Driver for PinePhone's Quectel LTE Modem...

```text
[manjaro@manjaro-arm ~]$ sudo lsusb -v
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0001 1.1 root hub
  bcdDevice            5.18
  iManufacturer           3 Linux 5.18.9-1-MANJARO-ARM ohci_hcd
  iProduct                2 Generic Platform OHCI controller
  iSerial                 1 1c1b400.usb
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0019
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0002  1x 2 bytes
        bInterval             255
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x000a
    No power switching (usb 1.0)
    Per-port overcurrent protection
  bPwrOn2PwrGood        2 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0100 power
Device Status:     0x0001
  Self Powered
Bus 002 Device 002: ID 2c7c:0125 Quectel Wireless Solutions Co., Ltd. EC25 LTE modem
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  idVendor           0x2c7c Quectel Wireless Solutions Co., Ltd.
  idProduct          0x0125 EC25 LTE modem
  bcdDevice            3.18
  iManufacturer           1 Quectel
  iProduct                2 EG25-G
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x00d1
    bNumInterfaces          5
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xa0
      (Bus Powered)
      Remote Wakeup
    MaxPower              500mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           2
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x01  EP 1 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        1
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      0
      bInterfaceProtocol      0
      iInterface              0
      ** UNRECOGNIZED:  05 24 00 10 01
      ** UNRECOGNIZED:  05 24 01 00 00
      ** UNRECOGNIZED:  04 24 02 02
      ** UNRECOGNIZED:  05 24 06 00 00
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x83  EP 3 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x000a  1x 10 bytes
        bInterval               9
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x82  EP 2 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x02  EP 2 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        2
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      0
      bInterfaceProtocol      0
      iInterface              0
      ** UNRECOGNIZED:  05 24 00 10 01
      ** UNRECOGNIZED:  05 24 01 00 00
      ** UNRECOGNIZED:  04 24 02 02
      ** UNRECOGNIZED:  05 24 06 00 00
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x85  EP 5 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x000a  1x 10 bytes
        bInterval               9
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x84  EP 4 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x03  EP 3 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        3
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass      0
      bInterfaceProtocol      0
      iInterface              0
      ** UNRECOGNIZED:  05 24 00 10 01
      ** UNRECOGNIZED:  05 24 01 00 00
      ** UNRECOGNIZED:  04 24 02 02
      ** UNRECOGNIZED:  05 24 06 00 00
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x87  EP 7 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x000a  1x 10 bytes
        bInterval               9
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x86  EP 6 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x04  EP 4 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        4
      bAlternateSetting       0
      bNumEndpoints           3
      bInterfaceClass       255 Vendor Specific Class
      bInterfaceSubClass    255 Vendor Specific Subclass
      bInterfaceProtocol    255 Vendor Specific Protocol
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x89  EP 9 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0008  1x 8 bytes
        bInterval               9
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x88  EP 8 IN
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x05  EP 5 OUT
        bmAttributes            2
          Transfer Type            Bulk
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0200  1x 512 bytes
        bInterval               0
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass          239 Miscellaneous Device
  bDeviceSubClass         2
  bDeviceProtocol         1 Interface Association
  bMaxPacketSize0        64
  bNumConfigurations      1
Device Status:     0x0000
  (Bus Powered)
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0002 2.0 root hub
  bcdDevice            5.18
  iManufacturer           3 Linux 5.18.9-1-MANJARO-ARM ehci_hcd
  iProduct                2 EHCI Host Controller
  iSerial                 1 1c1b000.usb
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0019
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x000a
    No power switching (usb 1.0)
    Per-port overcurrent protection
  bPwrOn2PwrGood       10 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0503 highspeed power enable connect
Device Status:     0x0001
  Self Powered
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0001 1.1 root hub
  bcdDevice            5.18
  iManufacturer           3 Linux 5.18.9-1-MANJARO-ARM ohci_hcd
  iProduct                2 Generic Platform OHCI controller
  iSerial                 1 1c1a400.usb
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0019
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0002  1x 2 bytes
        bInterval             255
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x000a
    No power switching (usb 1.0)
    Per-port overcurrent protection
  bPwrOn2PwrGood        2 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0100 power
Device Status:     0x0001
  Self Powered
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  idVendor           0x1d6b Linux Foundation
  idProduct          0x0002 2.0 root hub
  bcdDevice            5.18
  iManufacturer           3 Linux 5.18.9-1-MANJARO-ARM ehci_hcd
  iProduct                2 EHCI Host Controller
  iSerial                 1 1c1a000.usb
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength       0x0019
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower                0mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0
      bInterfaceProtocol      0 Full speed (or root) hub
      iInterface              0
      Endpoint Descriptor:
        bLength                 7
        bDescriptorType         5
        bEndpointAddress     0x81  EP 1 IN
        bmAttributes            3
          Transfer Type            Interrupt
          Synch Type               None
          Usage Type               Data
        wMaxPacketSize     0x0004  1x 4 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             1
  wHubCharacteristic 0x000a
    No power switching (usb 1.0)
    Per-port overcurrent protection
  bPwrOn2PwrGood       10 * 2 milli seconds
  bHubContrCurrent      0 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0100 power
Device Status:     0x0001
  Self Powered
```

## Testing Zig Backlight Driver on PinePhone

PinePhone Test Log for the following Zig Drivers...

-   ["Display Backlight"](https://lupyuen.github.io/articles/de#appendix-display-backlight)

-   ["Power Management Integrated Circuit"](https://lupyuen.github.io/articles/de#appendix-power-management-integrated-circuit)

-   ["Timing Controller (TCON0)"](https://lupyuen.github.io/articles/de#appendix-timing-controller-tcon0)

-   ["Enable MIPI DSI Block"](https://lupyuen.github.io/articles/dsi#appendix-enable-mipi-dsi-block)

-   ["Enable MIPI Display Physical Layer (DPHY)"](https://lupyuen.github.io/articles/dsi#appendix-enable-mipi-display-physical-layer-dphy)

-   ["Reset LCD Panel"](https://lupyuen.github.io/articles/de#appendix-reset-lcd-panel)

-   ["Start MIPI DSI HSC and HSD"](https://lupyuen.github.io/articles/dsi#appendix-start-mipi-dsi-hsc-and-hsd)

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
246286 bytes read in 14 ms (16.8 MiB/s)
Uncompressed size: 10465280 = 0x9FB000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 51 ms (20.2 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x40a7b000, heap_size=0x7585000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x40100000
up_timer_initialize: Before writing: vbar_el1=0x40280000
up_timer_initialize: After writing: vbar_el1=0x40100000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x40100000 _einit: 0x40100000 _stext: 0x40080000 _etext: 0x40101000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> 
nsh> 
nsh> uname -a
NuttX 11.0.0-RC2 a33f82d Dec  2 2022 17:57:39 arm64 qemu-a53
nsh> 
nsh> hello 3
task_spawn: name=hello entry=0x4009b4f8 file_actions=0x40a80580 attr=0x40a80588 argv=0x40a806d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
test_render: start, channels=3
backlight_enable: start, percent=90
Configure PL10 for PWM
  *0x1f02c04: clear 0x700, set 0x200
  *0x1f02c04 = 0x77277
Disable R_PWM
  *0x1f03800: clear 0x40, set 0x0
  *0x1f03800 = 0x0
Configure R_PWM Period
  *0x1f03804 = 0x4af0437
Enable R_PWM
  *0x1f03800 = 0x5f
Configure PH10 for Output
  *0x1c20900: clear 0x700, set 0x100
  *0x1c20900 = 0x7177
Set PH10 to High
  *0x1c2090c: clear 0x400, set 0x400
  *0x1c2090c = 0x400
backlight_enable: end
tcon0_init: start
Configure PLL_VIDEO0
  *0x1c20010 = 0x81006207
Enable LDO1 and LDO2
  *0x1c20040 = 0xc00000
Configure MIPI PLL
  *0x1c20040 = 0x80c0071a
Set TCON0 Clock Source to MIPI PLL
  *0x1c20118 = 0x80000000
Enable TCON0 Clock
  *0x1c20064 = 0x8
Deassert TCON0 Reset
  *0x1c202c4 = 0x8
Disable TCON0 and Interrupts
  *0x1c0c000 = 0x0
  *0x1c0c004 = 0x0
  *0x1c0c008 = 0x0
Enable Tristate Output
  *0x1c0c08c = 0xffffffff
  *0x1c0c0f4 = 0xffffffff
Set DCLK to MIPI PLL / 6
  *0x1c0c044 = 0x80000006
  *0x1c0c040 = 0x81000000
  *0x1c0c048 = 0x2cf059f
  *0x1c0c0f8 = 0x8
  *0x1c0c060 = 0x10010005
Set CPU Panel Trigger
  *0x1c0c160 = 0x2f02cf
  *0x1c0c164 = 0x59f
  *0x1c0c168 = 0x1bc2000a
Set Safe Period
  *0x1c0c1f0 = 0xbb80003
Enable Output Triggers
  *0x1c0c08c = 0xe0000000
Enable TCON0
  *0x1c0c000: clear 0x80000000, set 0x80000000
  *0x1c0c000 = 0x80000000
tcon0_init: end
display_board_init: start
Configure PD23 for Output
  *0x1c20874: clear 0x70000000, set 0x10000000
  *0x1c20874 = 0x17711177
Set PD23 to Low
  *0x1c2087c: clear 0x800000, set 0x0
  *0x1c2087c = 0x1c0000
Set DLDO1 Voltage to 3.3V
  pmic_write: reg=0x15, val=0x1a
  rsb_write: rt_addr=0x2d, reg_addr=0x15, value=0x1a
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x15
  *0x1f0341c = 0x1a
  *0x1f03400 = 0x80
  pmic_clrsetbits: reg=0x12, clr_mask=0x0, set_mask=0x8
  rsb_read: rt_addr=0x2d, reg_addr=0x12
  *0x1f0342c = 0x8b
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x12
  *0x1f03400 = 0x80
  rsb_write: rt_addr=0x2d, reg_addr=0x12, value=0xd9
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x12
  *0x1f0341c = 0xd9
  *0x1f03400 = 0x80
Set LDO Voltage to 3.3V
  pmic_write: reg=0x91, val=0x1a
  rsb_write: rt_addr=0x2d, reg_addr=0x91, value=0x1a
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x91
  *0x1f0341c = 0x1a
  *0x1f03400 = 0x80
Enable LDO mode on GPIO0
  pmic_write: reg=0x90, val=0x3
  rsb_write: rt_addr=0x2d, reg_addr=0x90, value=0x3
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x90
  *0x1f0341c = 0x3
  *0x1f03400 = 0x80
Set DLDO2 Voltage to 1.8V
  pmic_write: reg=0x16, val=0xb
  rsb_write: rt_addr=0x2d, reg_addr=0x16, value=0xb
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x16
  *0x1f0341c = 0xb
  *0x1f03400 = 0x80
  pmic_clrsetbits: reg=0x12, clr_mask=0x0, set_mask=0x10
  rsb_read: rt_addr=0x2d, reg_addr=0x12
  *0x1f0342c = 0x8b
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x12
  *0x1f03400 = 0x80
  rsb_write: rt_addr=0x2d, reg_addr=0x12, value=0xd9
  *0x1f0342c = 0x4e
  *0x1f03430 = 0x2d0000
  *0x1f03410 = 0x12
  *0x1f0341c = 0xd9
  *0x1f03400 = 0x80
Wait for power supply and power-on init
display_board_init: end
enable_dsi_block: start
Enable MIPI DSI Bus
  *0x1c20060: clear 0x2, set 0x2
  *0x1c20060 = 0x4742
  *0x1c202c0: clear 0x2, set 0x2
  *0x1c202c0 = 0x4742
Enable DSI Block
  *0x1ca0000 = 0x1
  *0x1ca0010 = 0x30000
  *0x1ca0060 = 0xa
  *0x1ca0078 = 0x0
Set Instructions
  *0x1ca0020 = 0x1f
  *0x1ca0024 = 0x10000001
  *0x1ca0028 = 0x20000010
  *0x1ca002c = 0x2000000f
  *0x1ca0030 = 0x30100001
  *0x1ca0034 = 0x40000010
  *0x1ca0038 = 0xf
  *0x1ca003c = 0x5000001f
Configure Jump Instructions
  *0x1ca004c = 0x560001
  *0x1ca02f8 = 0xff
Set Video Start Delay
  *0x1ca0014 = 0x5bc7
Set Burst
  *0x1ca007c = 0x10000007
Set Instruction Loop
  *0x1ca0040 = 0x30000002
  *0x1ca0044 = 0x310031
  *0x1ca0054 = 0x310031
Set Pixel Format
  *0x1ca0090 = 0x1308703e
  *0x1ca0098 = 0xffff
  *0x1ca009c = 0xffffffff
  *0x1ca0080 = 0x10008
Set Sync Timings
  *0x1ca000c = 0x0
  *0x1ca00b0 = 0x12000021
  *0x1ca00b4 = 0x1000031
  *0x1ca00b8 = 0x7000001
  *0x1ca00bc = 0x14000011
Set Basic Size
  *0x1ca0018 = 0x11000a
  *0x1ca001c = 0x5cd05a0
Set Horizontal Blanking
  *0x1ca00c0 = 0x9004a19
  *0x1ca00c4 = 0x50b40000
  *0x1ca00c8 = 0x35005419
  *0x1ca00cc = 0x757a0000
  *0x1ca00d0 = 0x9004a19
  *0x1ca00d4 = 0x50b40000
  *0x1ca00e0 = 0xc091a19
  *0x1ca00e4 = 0x72bd0000
Set Vertical Blanking
  *0x1ca00e8 = 0x1a000019
  *0x1ca00ec = 0xffff0000
enable_dsi_block: end
dphy_enable: start
Set DSI Clock to 150 MHz
  *0x1c20168 = 0x8203
Power on DPHY Tx
  *0x1ca1004 = 0x10000000
  *0x1ca1010 = 0xa06000e
  *0x1ca1014 = 0xa033207
  *0x1ca1018 = 0x1e
  *0x1ca101c = 0x0
  *0x1ca1020 = 0x303
Enable DPHY
  *0x1ca1000 = 0x31
  *0x1ca104c = 0x9f007f00
  *0x1ca1050 = 0x17000000
  *0x1ca105c = 0x1f01555
  *0x1ca1054 = 0x2
Enable LDOR, LDOC, LDOD
  *0x1ca1058 = 0x3040000
  *0x1ca1058: clear 0xf8000000, set 0xf8000000
  *0x1ca1058 = 0xfb040000
  *0x1ca1058: clear 0x4000000, set 0x4000000
  *0x1ca1058 = 0xff040000
  *0x1ca1054: clear 0x10, set 0x10
  *0x1ca1054 = 0x12
  *0x1ca1050: clear 0x80000000, set 0x80000000
  *0x1ca1050 = 0x97000000
  *0x1ca1054: clear 0xf000000, set 0xf000000
  *0x1ca1054 = 0xf000012
dphy_enable: end
panel_reset: start
Configure PD23 for Output
  *0x1c20874: clear 0x70000000, set 0x10000000
  *0x1c20874 = 0x17711177
Set PD23 to High
  *0x1c2087c: clear 0x800000, set 0x800000
  *0x1c2087c = 0x9c0000
wait for initialization
panel_reset: end
panel_init: start
writeDcs: len=4
b9 f1 12 83 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c b9 f1 12 83 
84 5d 
  *0x1ca0300: clear 0xffffffff, set 0x2c000439
  *0x1ca0304: clear 0xffffffff, set 0x8312f1b9
  *0x1ca0308: clear 0xffffffff, set 0x5d84
  *0x1ca0200: clear 0xff, set 0x9
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=28
ba 33 81 05 f9 0e 0e 20 
00 00 00 00 00 00 00 44 
25 00 91 0a 00 00 02 4f 
11 00 00 37 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=28
composeLongPacket: channel=0, cmd=0x39, len=28
packet: len=34
39 1c 00 2f ba 33 81 05 
f9 0e 0e 20 00 00 00 00 
00 00 00 44 25 00 91 0a 
00 00 02 4f 11 00 00 37 
2c e2 
  *0x1ca0300: clear 0xffffffff, set 0x2f001c39
  *0x1ca0304: clear 0xffffffff, set 0x58133ba
  *0x1ca0308: clear 0xffffffff, set 0x200e0ef9
  *0x1ca030c: clear 0xffffffff, set 0x0
  *0x1ca0310: clear 0xffffffff, set 0x44000000
  *0x1ca0314: clear 0xffffffff, set 0xa910025
  *0x1ca0318: clear 0xffffffff, set 0x4f020000
  *0x1ca031c: clear 0xffffffff, set 0x37000011
  *0x1ca0320: clear 0xffffffff, set 0xe22c
  *0x1ca0200: clear 0xff, set 0x21
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=5
b8 25 22 20 03 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=5
composeLongPacket: channel=0, cmd=0x39, len=5
packet: len=11
39 05 00 36 b8 25 22 20 
03 03 72 
  *0x1ca0300: clear 0xffffffff, set 0x36000539
  *0x1ca0304: clear 0xffffffff, set 0x202225b8
  *0x1ca0308: clear 0xffffffff, set 0x720303
  *0x1ca0200: clear 0xff, set 0xa
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=11
b3 10 10 05 05 03 ff 00 
00 00 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=11
composeLongPacket: channel=0, cmd=0x39, len=11
packet: len=17
39 0b 00 2c b3 10 10 05 
05 03 ff 00 00 00 00 6f 
bc 
  *0x1ca0300: clear 0xffffffff, set 0x2c000b39
  *0x1ca0304: clear 0xffffffff, set 0x51010b3
  *0x1ca0308: clear 0xffffffff, set 0xff0305
  *0x1ca030c: clear 0xffffffff, set 0x6f000000
  *0x1ca0310: clear 0xffffffff, set 0xbc
  *0x1ca0200: clear 0xff, set 0x10
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=10
c0 73 73 50 50 00 c0 08 
70 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=10
composeLongPacket: channel=0, cmd=0x39, len=10
packet: len=16
39 0a 00 36 c0 73 73 50 
50 00 c0 08 70 00 1b 6a

*0x1ca0300: clear 0xffffffff, set 0x36000a39
  *0x1ca0304: clear 0xffffffff, set 0x507373c0
  *0x1ca0308: clear 0xffffffff, set 0x8c00050
  *0x1ca030c: clear 0xffffffff, set 0x6a1b0070
  *0x1ca0200: clear 0xff, set 0xf
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=2
bc 4e 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 bc 4e 35 
  *0x1ca0300: clear 0xffffffff, set 0x354ebc15
  *0x1ca0200: clear 0xff, set 0x3
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=2
cc 0b 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 cc 0b 22 
  *0x1ca0300: clear 0xffffffff, set 0x220bcc15
  *0x1ca0200: clear 0xff, set 0x3
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=2
b4 80 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 b4 80 22 
  *0x1ca0300: clear 0xffffffff, set 0x2280b415
  *0x1ca0200: clear 0xff, set 0x3
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=4
b2 f0 12 f0 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c b2 f0 12 f0 
51 86 
  *0x1ca0300: clear 0xffffffff, set 0x2c000439
  *0x1ca0304: clear 0xffffffff, set 0xf012f0b2
  *0x1ca0308: clear 0xffffffff, set 0x8651
  *0x1ca0200: clear 0xff, set 0x9
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=15
e3 00 00 0b 0b 10 10 00 
00 00 00 ff 00 c0 10 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=15
composeLongPacket: channel=0, cmd=0x39, len=15
packet: len=21
39 0f 00 0f e3 00 00 0b 
0b 10 10 00 00 00 00 ff 
00 c0 10 36 0f 
  *0x1ca0300: clear 0xffffffff, set 0xf000f39
  *0x1ca0304: clear 0xffffffff, set 0xb0000e3
  *0x1ca0308: clear 0xffffffff, set 0x10100b
  *0x1ca030c: clear 0xffffffff, set 0xff000000
  *0x1ca0310: clear 0xffffffff, set 0x3610c000
  *0x1ca0314: clear 0xffffffff, set 0xf
  *0x1ca0200: clear 0xff, set 0x14
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=6
c6 01 00 ff ff 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=6
composeLongPacket: channel=0, cmd=0x39, len=6
packet: len=12
39 06 00 30 c6 01 00 ff 
ff 00 8e 25 
  *0x1ca0300: clear 0xffffffff, set 0x30000639
  *0x1ca0304: clear 0xffffffff, set 0xff0001c6
  *0x1ca0308: clear 0xffffffff, set 0x258e00ff
  *0x1ca0200: clear 0xff, set 0xb
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=13
c1 74 00 32 32 77 f1 ff 
ff cc cc 77 77 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=13
composeLongPacket: channel=0, cmd=0x39, len=13
packet: len=19
39 0d 00 13 c1 74 00 32 
32 77 f1 ff ff cc cc 77 
77 69 e4 
  *0x1ca0300: clear 0xffffffff, set 0x13000d39
  *0x1ca0304: clear 0xffffffff, set 0x320074c1
  *0x1ca0308: clear 0xffffffff, set 0xfff17732
  *0x1ca030c: clear 0xffffffff, set 0x77ccccff
  *0x1ca0310: clear 0xffffffff, set 0xe46977
  *0x1ca0200: clear 0xff, set 0x12
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=3
b5 07 07 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=3
composeLongPacket: channel=0, cmd=0x39, len=3
packet: len=9
39 03 00 09 b5 07 07 7b 
b3 
  *0x1ca0300: clear 0xffffffff, set 0x9000339
  *0x1ca0304: clear 0xffffffff, set 0x7b0707b5
  *0x1ca0308: clear 0xffffffff, set 0xb3
  *0x1ca0200: clear 0xff, set 0x8
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=3
b6 2c 2c 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=3
composeLongPacket: channel=0, cmd=0x39, len=3
packet: len=9
39 03 00 09 b6 2c 2c 55 
04 
  *0x1ca0300: clear 0xffffffff, set 0x9000339
  *0x1ca0304: clear 0xffffffff, set 0x552c2cb6
  *0x1ca0308: clear 0xffffffff, set 0x4
  *0x1ca0200: clear 0xff, set 0x8
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=4
bf 02 11 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c bf 02 11 00 
b5 e9 
  *0x1ca0300: clear 0xffffffff, set 0x2c000439
  *0x1ca0304: clear 0xffffffff, set 0x1102bf
  *0x1ca0308: clear 0xffffffff, set 0xe9b5
  *0x1ca0200: clear 0xff, set 0x9
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=64
e9 82 10 06 05 a2 0a a5 
12 31 23 37 83 04 bc 27 
38 0c 00 03 00 00 00 0c 
00 03 00 00 00 75 75 31 
88 88 88 88 88 88 13 88 
64 64 20 88 88 88 88 88 
88 02 88 00 00 00 00 00 
00 00 00 00 00 00 00 00

mipi_dsi_dcs_write: channel=0, cmd=0x39, len=64
composeLongPacket: channel=0, cmd=0x39, len=64
packet: len=70
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
  *0x1ca0300: clear 0xffffffff, set 0x25004039
  *0x1ca0304: clear 0xffffffff, set 0x61082e9
  *0x1ca0308: clear 0xffffffff, set 0xa50aa205
  *0x1ca030c: clear 0xffffffff, set 0x37233112
  *0x1ca0310: clear 0xffffffff, set 0x27bc0483
  *0x1ca0314: clear 0xffffffff, set 0x3000c38
  *0x1ca0318: clear 0xffffffff, set 0xc000000
  *0x1ca031c: clear 0xffffffff, set 0x300
  *0x1ca0320: clear 0xffffffff, set 0x31757500
  *0x1ca0324: clear 0xffffffff, set 0x88888888
  *0x1ca0328: clear 0xffffffff, set 0x88138888
  *0x1ca032c: clear 0xffffffff, set 0x88206464
  *0x1ca0330: clear 0xffffffff, set 0x88888888
  *0x1ca0334: clear 0xffffffff, set 0x880288
  *0x1ca0338: clear 0xffffffff, set 0x0
  *0x1ca033c: clear 0xffffffff, set 0x0
  *0x1ca0340: clear 0xffffffff, set 0x0
  *0x1ca0344: clear 0xffffffff, set 0x365
  *0x1ca0200: clear 0xff, set 0x45
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=62
ea 02 21 00 00 00 00 00 
00 00 00 00 00 02 46 02 
88 88 88 88 88 88 64 88 
13 57 13 88 88 88 88 88 
88 75 88 23 14 00 00 02 
00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 03 
0a a5 00 00 00 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=62
composeLongPacket: channel=0, cmd=0x39, len=62
packet: len=68
39 3e 00 1a ea 02 21 00 
00 00 00 00 00 00 00 00 
00 02 46 02 88 88 88 88 
88 88 64 88 13 57 13 88 
88 88 88 88 88 75 88 23 
14 00 00 02 00 00 00 00 
00 00 00 00 00 00 00 00 
00 00 00 03 0a a5 00 00 
00 00 24 1b 
  *0x1ca0300: clear 0xffffffff, set 0x1a003e39
  *0x1ca0304: clear 0xffffffff, set 0x2102ea
  *0x1ca0308: clear 0xffffffff, set 0x0
  *0x1ca030c: clear 0xffffffff, set 0x0
  *0x1ca0310: clear 0xffffffff, set 0x2460200
  *0x1ca0314: clear 0xffffffff, set 0x88888888
  *0x1ca0318: clear 0xffffffff, set 0x88648888
  *0x1ca031c: clear 0xffffffff, set 0x88135713
  *0x1ca0320: clear 0xffffffff, set 0x88888888
  *0x1ca0324: clear 0xffffffff, set 0x23887588
  *0x1ca0328: clear 0xffffffff, set 0x2000014
  *0x1ca032c: clear 0xffffffff, set 0x0
  *0x1ca0330: clear 0xffffffff, set 0x0
  *0x1ca0334: clear 0xffffffff, set 0x0
  *0x1ca0338: clear 0xffffffff, set 0x3000000
  *0x1ca033c: clear 0xffffffff, set 0xa50a
  *0x1ca0340: clear 0xffffffff, set 0x1b240000
  *0x1ca0200: clear 0xff, set 0x43
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=35
e0 00 09 0d 23 27 3c 41 
35 07 0d 0e 12 13 10 12 
12 18 00 09 0d 23 27 3c 
41 35 07 0d 0e 12 13 10 
12 12 18 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=35
composeLongPacket: channel=0, cmd=0x39, len=35
packet: len=41
39 23 00 20 e0 00 09 0d 
23 27 3c 41 35 07 0d 0e 
12 13 10 12 12 18 00 09 
0d 23 27 3c 41 35 07 0d 
0e 12 13 10 12 12 18 93 
bf 
  *0x1ca0300: clear 0xffffffff, set 0x20002339
  *0x1ca0304: clear 0xffffffff, set 0xd0900e0
  *0x1ca0308: clear 0xffffffff, set 0x413c2723
  *0x1ca030c: clear 0xffffffff, set 0xe0d0735
  *0x1ca0310: clear 0xffffffff, set 0x12101312
  *0x1ca0314: clear 0xffffffff, set 0x9001812
  *0x1ca0318: clear 0xffffffff, set 0x3c27230d
  *0x1ca031c: clear 0xffffffff, set 0xd073541
  *0x1ca0320: clear 0xffffffff, set 0x1013120e
  *0x1ca0324: clear 0xffffffff, set 0x93181212
  *0x1ca0328: clear 0xffffffff, set 0xbf
  *0x1ca0200: clear 0xff, set 0x28
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=1
11 
mipi_dsi_dcs_write: channel=0, cmd=0x5, len=1
composeShortPacket: channel=0, cmd=0x5, len=1
packet: len=4
05 11 00 36 
  *0x1ca0300: clear 0xffffffff, set 0x36001105
  *0x1ca0200: clear 0xff, set 0x3
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
writeDcs: len=1
29 
mipi_dsi_dcs_write: channel=0, cmd=0x5, len=1
composeShortPacket: channel=0, cmd=0x5, len=1
packet: len=4
05 29 00 1c 
  *0x1ca0300: clear 0xffffffff, set 0x1c002905
  *0x1ca0200: clear 0xff, set 0x3
  *0x1ca0010: clear 0x1, set 0x0
  *0x1ca0010: clear 0x1, set 0x1
panel_init: end
start_dsi: start
Start HSC
  *0x1ca0048 = 0xf02
Commit
  *0x1ca0010: clear 0x1, set 0x1
  *0x1ca0010 = 0x30001
Instruction Function Lane
  *0x1ca0020: clear 0x10, set 0x0
  *0x1ca0020 = 0xf
Start HSD
  *0x1ca0048 = 0x63f07006
Commit
  *0x1ca0010: clear 0x1, set 0x1
  *0x1ca0010 = 0x30001
start_dsi: end
de2_init: start
Set High Speed SRAM to DMA Mode
  *0x1c00004 = 0x0
Set Display Engine PLL to 297 MHz
  *0x1c20048 = 0x81001701
Wait for Display Engine PLL to be stable
Set Special Clock to Display Engine PLL
  *0x1c20104: clear 0x87000000, set 0x81000000
  *0x1c20104 = 0x81000000
Enable AHB for Display Engine: De-Assert Display Engine
  *0x1c202c4: clear 0x1000, set 0x1000
  *0x1c202c4 = 0x1008
Enable AHB for Display Engine: Pass Display Engine
  *0x1c20064: clear 0x1000, set 0x1000
  *0x1c20064 = 0x1008
Enable Clock for MIXER0: SCLK Clock Pass
  *0x1000000: clear 0x1, set 0x1
  *0x1000000 = 0x1
Enable Clock for MIXER0: HCLK Clock Reset Off
  *0x1000008: clear 0x1, set 0x1
  *0x1000008 = 0x1
Enable Clock for MIXER0: HCLK Clock Pass
  *0x1000004: clear 0x1, set 0x1
  *0x1000004 = 0x1
Route MIXER0 to TCON0
  *0x1000010: clear 0x1, set 0x0
  *0x1000010 = 0x0
Clear MIXER0 Registers: GLB, BLD, OVL_V, OVL_UI
  *0x1100000 = 0x0
  to *0x1105fff = 0x0
Disable MIXER0 VSU
  *0x1120000 = 0x0
Disable MIXER0 Undocumented
  *0x1130000 = 0x0
Disable MIXER0 UI_SCALER1
  *0x1140000 = 0x0
Disable MIXER0 UI_SCALER2
  *0x1150000 = 0x0
Disable MIXER0 FCE
  *0x11a0000 = 0x0
Disable MIXER0 BWS
  *0x11a2000 = 0x0
Disable MIXER0 LTI
  *0x11a4000 = 0x0
Disable MIXER0 PEAKING
  *0x11a6000 = 0x0
Disable MIXER0 ASE
  *0x11a8000 = 0x0
Disable MIXER0 FCC
  *0x11aa000 = 0x0
Disable MIXER0 DRC
  *0x11b0000 = 0x0
Enable MIXER0
  *0x1100000 = 0x1
de2_init: end
renderGraphics: start
initUiBlender: start
Set Blender Background
  *0x1101088 = 0xff000000
Set Blender Pre-Multiply
  *0x1101084 = 0x0
initUiBlender: end
initUiChannel: start
Channel 1: Set Overlay (720 x 1440)
  *0x1103000 = 0xff000405
  *0x1103010 = 0x4012c000
  *0x110300c = 0xb40
  *0x1103004 = 0x59f02cf
  *0x1103088 = 0x59f02cf
  *0x1103008 = 0x0
Channel 1: Set Blender Output
  *0x110108c = 0x59f02cf
  *0x110000c = 0x59f02cf
Channel 1: Set Blender Input Pipe 0 (720 x 1440)
  *0x1101008 = 0x59f02cf
  *0x1101004 = 0xff000000
  *0x110100c = 0x0
  *0x1101090 = 0x3010301
Channel 1: Disable Scaler
  *0x1140000 = 0x0
initUiChannel: end
initUiChannel: start
Channel 2: Set Overlay (600 x 600)
  *0x1104000 = 0xff000005
  *0x1104010 = 0x40521000
  *0x110400c = 0x960
  *0x1104004 = 0x2570257
  *0x1104088 = 0x2570257
  *0x1104008 = 0x0
Channel 2: Set Blender Input Pipe 1 (600 x 600)
  *0x1101018 = 0x2570257
  *0x1101014 = 0xff000000
  *0x110101c = 0x340034
  *0x1101094 = 0x3010301
Channel 2: Disable Scaler
  *0x1150000 = 0x0
initUiChannel: end
initUiChannel: start
Channel 3: Set Overlay (720 x 1440)
  *0x1105000 = 0x7f000005
  *0x1105010 = 0x40681000
  *0x110500c = 0xb40
  *0x1105004 = 0x59f02cf
  *0x1105088 = 0x59f02cf
  *0x1105008 = 0x0
Channel 3: Set Blender Input Pipe 2 (720 x 1440)
  *0x1101028 = 0x59f02cf
  *0x1101024 = 0xff000000
  *0x110102c = 0x0
  *0x1101098 = 0x3010301
Channel 3: Disable Scaler
  *0x1160000 = 0x0
initUiChannel: end
applySettings: start
Set Blender Route
  *0x1101080 = 0x321
Enable Blender Pipes
  *0x1101000 = 0x701
Apply Settings
  *0x1100008 = 0x1
applySettings: end
renderGraphics: end
test_render: end
HELLO ZIG ON PINEPHONE!
test_zig: start
Testing Compose Short Packet (Without Parameter)...
composeShortPacket: channel=0, cmd=0x5, len=1
Result:
05 11 00 36 
Testing Compose Short Packet (With Parameter)...
composeShortPacket: channel=0, cmd=0x15, len=2
Result:
15 bc 4e 35 
Testing Compose Long Packet...
composeLongPacket: channel=0, cmd=0x39, len=64
Result:
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
test_zig: end
nsh> 
nsh> 
```

## Testing Zig Display Engine Driver on PinePhone

See ["p-boot Display Code"](https://gist.github.com/lupyuen/c12f64cf03d3a81e9c69f9fef49d9b70)

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
220236 bytes read in 14 ms (15 MiB/s)
Uncompressed size: 10268672 = 0x9CB000
36162 bytes read in 5 ms (6.9 MiB/s)
1078500 bytes read in 50 ms (20.6 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x40a4b000, heap_size=0x75b5000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400d7000
up_timer_initialize: Before writing: vbar_el1=0x40257000
up_timer_initialize: After writing: vbar_el1=0x400d7000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400d7000 _einit: 0x400d7000 _stext: 0x40080000 _etext: 0x400d8000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> hello
task_spawn: name=hello entry=0x4009d490 file_actions=0x40a50580 attr=0x40a50588 argv=0x40a506d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
tcon0_init: start
PLL_VIDEO0
  0x1c20010 = 0x81006207 (DMB)
PLL_MIPI
  0x1c20040 = 0xc00000 (DMB)
  udelay 100
  0x1c20040 = 0x80c0071a (DMB)
TCON0 source MIPI_PLL
  0x1c20118 = 0x80000000 (DMB)
Clock on
  0x1c20064 = 0x8 (DMB)
Reset off
  0x1c202c4 = 0x8 (DMB)
Init lcdc: Disable tcon, Disable all interrupts
  0x1c0c000 = 0x0 (DMB)
  0x1c0c004 = 0x0
  0x1c0c008 = 0x0
Set all io lines to tristate
  0x1c0c08c = 0xffffffff
  0x1c0c0f4 = 0xffffffff
mode set: DCLK = MIPI_PLL / 6
  0x1c0c044 = 0x80000006
  0x1c0c040 = 0x81000000
  0x1c0c048 = 0x2cf059f
  0x1c0c0f8 = 0x8
  0x1c0c060 = 0x10010005
The datasheet says that this should be set higher than 20 * pixel cycle, but it's not clear what a pixel cycle is.
  0x1c0c160 = 0x2f02cf
  0x1c0c164 = 0x59f
  0x1c0c168 = 0x1bc2000a
The Allwinner BSP has a comment that the period should be the display clock * 15, but uses an hardcoded 3000
  0x1c0c1f0 = 0xbb80003
Enable the output on the pins
  0x1c0c08c = 0xe0000000 (DMB)
enable tcon as a whole
  setbits 0x1c0c000, 0x80000000 (DMB)
tcon0_init: end
dsi_init: start
display_board_init: start
assert reset: GPD(23), 0  // PD23 - LCD-RST (active low)
sunxi_gpio_set_cfgpin: pin=0x77, val=1
sunxi_gpio_set_cfgbank: bank_offset=119, val=1
  clrsetbits 0x1c20874, 0xf0000000, 0x10000000
sunxi_gpio_output: pin=0x77, val=0
  before: 0x1c2087c = 0x1c0000
  after: 0x1c2087c = 0x1c0000 (DMB)
dldo1 3.3V
  pmic_write: reg=0x15, val=0x1a
  rsb_write: rt_addr=0x2d, reg_addr=0x15, value=0x1a
  pmic_clrsetbits: reg=0x12, clr_mask=0x0, set_mask=0x8
  rsb_read: rt_addr=0x2d, reg_addr=0x12
  rsb_write: rt_addr=0x2d, reg_addr=0x12, value=0xd9
ldo_io0 3.3V
  pmic_write: reg=0x91, val=0x1a
  rsb_write: rt_addr=0x2d, reg_addr=0x91, value=0x1a
  pmic_write: reg=0x90, val=0x3
  rsb_write: rt_addr=0x2d, reg_addr=0x90, value=0x3
dldo2 1.8V
  pmic_write: reg=0x16, val=0xb
  rsb_write: rt_addr=0x2d, reg_addr=0x16, value=0xb
  pmic_clrsetbits: reg=0x12, clr_mask=0x0, set_mask=0x10
  rsb_read: rt_addr=0x2d, reg_addr=0x12
  rsb_write: rt_addr=0x2d, reg_addr=0x12, value=0xd9
wait for power supplies and power-on init
  udelay 15000
display_board_init: end
mipi dsi bus enable
  setbits 0x1c20060, 0x2 (DMB)
  setbits 0x1c202c0, 0x2 (DMB)
Enable the DSI block
struct reg_inst dsi_init_seq[] = {
.{ 0x0000, 0x00000001 },  // DMB
.{ 0x0010, 0x00030000 },  // DMB
.{ 0x0060, 0x0000000a },  // DMB
.{ 0x0078, 0x00000000 },  // DMB
inst_init
.{ 0x0020, 0x0000001f },  // DMB
.{ 0x0024, 0x10000001 },  // DMB
.{ 0x0028, 0x20000010 },  // DMB
.{ 0x002c, 0x2000000f },  // DMB
.{ 0x0030, 0x30100001 },  // DMB
.{ 0x0034, 0x40000010 },  // DMB
.{ 0x0038, 0x0000000f },  // DMB
.{ 0x003c, 0x5000001f },  // DMB
.{ 0x004c, 0x00560001 },  // DMB
.{ 0x02f8, 0x000000ff },  // DMB
get_video_start_delay
.{ 0x0014, 0x00005bc7 },  // DMB
setup_burst
.{ 0x007c, 0x10000007 },  // DMB
setup_inst_loop
.{ 0x0040, 0x30000002 },  // DMB
.{ 0x0044, 0x00310031 },  // DMB
.{ 0x0054, 0x00310031 },  // DMB
setup_format
.{ 0x0090, 0x1308703e },  // DMB
.{ 0x0098, 0x0000ffff },  // DMB
.{ 0x009c, 0xffffffff },  // DMB
.{ 0x0080, 0x00010008 },  // DMB
setup_timings
display_malloc: size=2330
.{ 0x000c, 0x00000000 },  // DMB
.{ 0x00b0, 0x12000021 },  // DMB
.{ 0x00b4, 0x01000031 },  // DMB
.{ 0x00b8, 0x07000001 },  // DMB
.{ 0x00bc, 0x14000011 },  // DMB
.{ 0x0018, 0x0011000a },  // DMB
.{ 0x001c, 0x05cd05a0 },  // DMB
.{ 0x00c0, 0x09004a19 },  // DMB
.{ 0x00c4, 0x50b40000 },  // DMB
.{ 0x00c8, 0x35005419 },  // DMB
.{ 0x00cc, 0x757a0000 },  // DMB
.{ 0x00d0, 0x09004a19 },  // DMB
.{ 0x00d4, 0x50b40000 },  // DMB
.{ 0x00e0, 0x0c091a19 },  // DMB
.{ 0x00e4, 0x72bd0000 },  // DMB
.{ 0x00e8, 0x1a000019 },  // DMB
.{ 0x00ec, 0xffff0000 },  // DMB
};
dphy_enable: start
150MHz (600 / 4)
  0x1c20168 = 0x8203 (DMB)
  0x1ca1004 = 0x10000000 (DMB)
  0x1ca1010 = 0xa06000e (DMB)
  0x1ca1014 = 0xa033207 (DMB)
  0x1ca1018 = 0x1e (DMB)
  0x1ca101c = 0x0 (DMB)
  0x1ca1020 = 0x303 (DMB)
  0x1ca1000 = 0x31 (DMB)
  0x1ca104c = 0x9f007f00 (DMB)
  0x1ca1050 = 0x17000000 (DMB)
  0x1ca105c = 0x1f01555 (DMB)
  0x1ca1054 = 0x2 (DMB)
  udelay 5
  0x1ca1058 = 0x3040000 (DMB)
  udelay 1
  update_bits 0x1ca1058, 0xf8000000, 0xf8000000 (DMB)
  udelay 1
  update_bits 0x1ca1058, 0x4000000, 0x4000000 (DMB)
  udelay 1
  update_bits 0x1ca1054, 0x10, 0x10 (DMB)
  udelay 1
  update_bits 0x1ca1050, 0x80000000, 0x80000000 (DMB)
  update_bits 0x1ca1054, 0xf000000, 0xf000000 (DMB)
dphy_enable: end
deassert reset: GPD(23), 1  // PD23 - LCD-RST (active low)
sunxi_gpio_set_cfgpin: pin=0x77, val=1
sunxi_gpio_set_cfgbank: bank_offset=119, val=1
  clrsetbits 0x1c20874, 0xf0000000, 0x10000000
sunxi_gpio_output: pin=0x77, val=1
  before: 0x1c2087c = 0x1c0000
  after: 0x1c2087c = 0x9c0000 (DMB)
wait for initialization
udelay 15000

struct reg_inst dsi_panel_init_seq[] = {
nuttx_panel_init
writeDcs: len=4
b9 f1 12 83 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c b9 f1 12 83 
84 5d 
modifyreg32: addr=0x300, val=0x2c000439
modifyreg32: addr=0x304, val=0x8312f1b9
modifyreg32: addr=0x308, val=0x00005d84
modifyreg32: addr=0x200, val=0x00000009
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=28
ba 33 81 05 f9 0e 0e 20 
00 00 00 00 00 00 00 44 
25 00 91 0a 00 00 02 4f 
11 00 00 37 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=28
composeLongPacket: channel=0, cmd=0x39, len=28
packet: len=34
39 1c 00 2f ba 33 81 05 
f9 0e 0e 20 00 00 00 00 
00 00 00 44 25 00 91 0a 
00 00 02 4f 11 00 00 37 
2c e2 
modifyreg32: addr=0x300, val=0x2f001c39
modifyreg32: addr=0x304, val=0x058133ba
modifyreg32: addr=0x308, val=0x200e0ef9
modifyreg32: addr=0x30c, val=0x00000000
modifyreg32: addr=0x310, val=0x44000000
modifyreg32: addr=0x314, val=0x0a910025
modifyreg32: addr=0x318, val=0x4f020000
modifyreg32: addr=0x31c, val=0x37000011
modifyreg32: addr=0x320, val=0x0000e22c
modifyreg32: addr=0x200, val=0x00000021
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=5
b8 25 22 20 03 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=5
composeLongPacket: channel=0, cmd=0x39, len=5
packet: len=11
39 05 00 36 b8 25 22 20 
03 03 72 
modifyreg32: addr=0x300, val=0x36000539
modifyreg32: addr=0x304, val=0x202225b8
modifyreg32: addr=0x308, val=0x00720303
modifyreg32: addr=0x200, val=0x0000000a
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=11
b3 10 10 05 05 03 ff 00 
00 00 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=11
composeLongPacket: channel=0, cmd=0x39, len=11
packet: len=17
39 0b 00 2c b3 10 10 05 
05 03 ff 00 00 00 00 6f 
bc 
modifyreg32: addr=0x300, val=0x2c000b39
modifyreg32: addr=0x304, val=0x051010b3
modifyreg32: addr=0x308, val=0x00ff0305
modifyreg32: addr=0x30c, val=0x6f000000
modifyreg32: addr=0x310, val=0x000000bc
modifyreg32: addr=0x200, val=0x00000010
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=10
c0 73 73 50 50 00 c0 08 
70 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=10
composeLongPacket: channel=0, cmd=0x39, len=10
packet: len=16
39 0a 00 36 c0 73 73 50 
50 00 c0 08 70 00 1b 6a

modifyreg32: addr=0x300, val=0x36000a39
modifyreg32: addr=0x304, val=0x507373c0
modifyreg32: addr=0x308, val=0x08c00050
modifyreg32: addr=0x30c, val=0x6a1b0070
modifyreg32: addr=0x200, val=0x0000000f
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=2
bc 4e 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 bc 4e 35 
modifyreg32: addr=0x300, val=0x354ebc15
modifyreg32: addr=0x200, val=0x00000003
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=2
cc 0b 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 cc 0b 22 
modifyreg32: addr=0x300, val=0x220bcc15
modifyreg32: addr=0x200, val=0x00000003
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=2
b4 80 
mipi_dsi_dcs_write: channel=0, cmd=0x15, len=2
composeShortPacket: channel=0, cmd=0x15, len=2
packet: len=4
15 b4 80 22 
modifyreg32: addr=0x300, val=0x2280b415
modifyreg32: addr=0x200, val=0x00000003
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=4
b2 f0 12 f0 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c b2 f0 12 f0 
51 86 
modifyreg32: addr=0x300, val=0x2c000439
modifyreg32: addr=0x304, val=0xf012f0b2
modifyreg32: addr=0x308, val=0x00008651
modifyreg32: addr=0x200, val=0x00000009
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=15
e3 00 00 0b 0b 10 10 00 
00 00 00 ff 00 c0 10 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=15
composeLongPacket: channel=0, cmd=0x39, len=15
packet: len=21
39 0f 00 0f e3 00 00 0b 
0b 10 10 00 00 00 00 ff 
00 c0 10 36 0f 
modifyreg32: addr=0x300, val=0x0f000f39
modifyreg32: addr=0x304, val=0x0b0000e3
modifyreg32: addr=0x308, val=0x0010100b
modifyreg32: addr=0x30c, val=0xff000000
modifyreg32: addr=0x310, val=0x3610c000
modifyreg32: addr=0x314, val=0x0000000f
modifyreg32: addr=0x200, val=0x00000014
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=6
c6 01 00 ff ff 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=6
composeLongPacket: channel=0, cmd=0x39, len=6
packet: len=12
39 06 00 30 c6 01 00 ff 
ff 00 8e 25 
modifyreg32: addr=0x300, val=0x30000639
modifyreg32: addr=0x304, val=0xff0001c6
modifyreg32: addr=0x308, val=0x258e00ff
modifyreg32: addr=0x200, val=0x0000000b
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=13
c1 74 00 32 32 77 f1 ff 
ff cc cc 77 77 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=13
composeLongPacket: channel=0, cmd=0x39, len=13
packet: len=19
39 0d 00 13 c1 74 00 32 
32 77 f1 ff ff cc cc 77 
77 69 e4 
modifyreg32: addr=0x300, val=0x13000d39
modifyreg32: addr=0x304, val=0x320074c1
modifyreg32: addr=0x308, val=0xfff17732
modifyreg32: addr=0x30c, val=0x77ccccff
modifyreg32: addr=0x310, val=0x00e46977
modifyreg32: addr=0x200, val=0x00000012
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=3
b5 07 07 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=3
composeLongPacket: channel=0, cmd=0x39, len=3
packet: len=9
39 03 00 09 b5 07 07 7b 
b3 
modifyreg32: addr=0x300, val=0x09000339
modifyreg32: addr=0x304, val=0x7b0707b5
modifyreg32: addr=0x308, val=0x000000b3
modifyreg32: addr=0x200, val=0x00000008
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=3
b6 2c 2c 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=3
composeLongPacket: channel=0, cmd=0x39, len=3
packet: len=9
39 03 00 09 b6 2c 2c 55 
04 
modifyreg32: addr=0x300, val=0x09000339
modifyreg32: addr=0x304, val=0x552c2cb6
modifyreg32: addr=0x308, val=0x00000004
modifyreg32: addr=0x200, val=0x00000008
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=4
bf 02 11 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=4
composeLongPacket: channel=0, cmd=0x39, len=4
packet: len=10
39 04 00 2c bf 02 11 00 
b5 e9 
modifyreg32: addr=0x300, val=0x2c000439
modifyreg32: addr=0x304, val=0x001102bf
modifyreg32: addr=0x308, val=0x0000e9b5
modifyreg32: addr=0x200, val=0x00000009
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=64
e9 82 10 06 05 a2 0a a5 
12 31 23 37 83 04 bc 27 
38 0c 00 03 00 00 00 0c 
00 03 00 00 00 75 75 31 
88 88 88 88 88 88 13 88 
64 64 20 88 88 88 88 88 
88 02 88 00 00 00 00 00 
00 00 00 00 00 00 00 00

mipi_dsi_dcs_write: channel=0, cmd=0x39, len=64
composeLongPacket: channel=0, cmd=0x39, len=64
packet: len=70
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
modifyreg32: addr=0x300, val=0x25004039
modifyreg32: addr=0x304, val=0x061082e9
modifyreg32: addr=0x308, val=0xa50aa205
modifyreg32: addr=0x30c, val=0x37233112
modifyreg32: addr=0x310, val=0x27bc0483
modifyreg32: addr=0x314, val=0x03000c38
modifyreg32: addr=0x318, val=0x0c000000
modifyreg32: addr=0x31c, val=0x00000300
modifyreg32: addr=0x320, val=0x31757500
modifyreg32: addr=0x324, val=0x88888888
modifyreg32: addr=0x328, val=0x88138888
modifyreg32: addr=0x32c, val=0x88206464
modifyreg32: addr=0x330, val=0x88888888
modifyreg32: addr=0x334, val=0x00880288
modifyreg32: addr=0x338, val=0x00000000
modifyreg32: addr=0x33c, val=0x00000000
modifyreg32: addr=0x340, val=0x00000000
modifyreg32: addr=0x344, val=0x00000365
modifyreg32: addr=0x200, val=0x00000045
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=62
ea 02 21 00 00 00 00 00 
00 00 00 00 00 02 46 02 
88 88 88 88 88 88 64 88 
13 57 13 88 88 88 88 88 
88 75 88 23 14 00 00 02 
00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 03 
0a a5 00 00 00 00 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=62
composeLongPacket: channel=0, cmd=0x39, len=62
packet: len=68
39 3e 00 1a ea 02 21 00 
00 00 00 00 00 00 00 00 
00 02 46 02 88 88 88 88 
88 88 64 88 13 57 13 88 
88 88 88 88 88 75 88 23 
14 00 00 02 00 00 00 00 
00 00 00 00 00 00 00 00 
00 00 00 03 0a a5 00 00 
00 00 24 1b 
modifyreg32: addr=0x300, val=0x1a003e39
modifyreg32: addr=0x304, val=0x002102ea
modifyreg32: addr=0x308, val=0x00000000
modifyreg32: addr=0x30c, val=0x00000000
modifyreg32: addr=0x310, val=0x02460200
modifyreg32: addr=0x314, val=0x88888888
modifyreg32: addr=0x318, val=0x88648888
modifyreg32: addr=0x31c, val=0x88135713
modifyreg32: addr=0x320, val=0x88888888
modifyreg32: addr=0x324, val=0x23887588
modifyreg32: addr=0x328, val=0x02000014
modifyreg32: addr=0x32c, val=0x00000000
modifyreg32: addr=0x330, val=0x00000000
modifyreg32: addr=0x334, val=0x00000000
modifyreg32: addr=0x338, val=0x03000000
modifyreg32: addr=0x33c, val=0x0000a50a
modifyreg32: addr=0x340, val=0x1b240000
modifyreg32: addr=0x200, val=0x00000043
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=35
e0 00 09 0d 23 27 3c 41 
35 07 0d 0e 12 13 10 12 
12 18 00 09 0d 23 27 3c 
41 35 07 0d 0e 12 13 10 
12 12 18 
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=35
composeLongPacket: channel=0, cmd=0x39, len=35
packet: len=41
39 23 00 20 e0 00 09 0d 
23 27 3c 41 35 07 0d 0e 
12 13 10 12 12 18 00 09 
0d 23 27 3c 41 35 07 0d 
0e 12 13 10 12 12 18 93 
bf 
modifyreg32: addr=0x300, val=0x20002339
modifyreg32: addr=0x304, val=0x0d0900e0
modifyreg32: addr=0x308, val=0x413c2723
modifyreg32: addr=0x30c, val=0x0e0d0735
modifyreg32: addr=0x310, val=0x12101312
modifyreg32: addr=0x314, val=0x09001812
modifyreg32: addr=0x318, val=0x3c27230d
modifyreg32: addr=0x31c, val=0x0d073541
modifyreg32: addr=0x320, val=0x1013120e
modifyreg32: addr=0x324, val=0x93181212
modifyreg32: addr=0x328, val=0x000000bf
modifyreg32: addr=0x200, val=0x00000028
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=1
11 
mipi_dsi_dcs_write: channel=0, cmd=0x5, len=1
composeShortPacket: channel=0, cmd=0x5, len=1
packet: len=4
05 11 00 36 
modifyreg32: addr=0x300, val=0x36001105
modifyreg32: addr=0x200, val=0x00000003
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
writeDcs: len=1
29 
mipi_dsi_dcs_write: channel=0, cmd=0x5, len=1
composeShortPacket: channel=0, cmd=0x5, len=1
packet: len=4
05 29 00 1c 
modifyreg32: addr=0x300, val=0x1c002905
modifyreg32: addr=0x200, val=0x00000003
modifyreg32: addr=0x010, val=0x00000000
modifyreg32: addr=0x010, val=0x00000001
};
dsi_start DSI_START_HSC
.{ 0x0048, 0x00000f02 },  // DMB
.{ MAGIC_COMMIT, 0 },  // DMB
dsi_update_bits: 0x01ca0020 : 0000001f -> (00000010) 00000000 (DMB)
udelay 1000
dsi_start DSI_START_HSD
.{ 0x0048, 0x63f07006 },  // DMB
.{ MAGIC_COMMIT, 0 },  // DMB
dsi_init: end
de2_init
Set SRAM for video use
  0x1c00004 = 0x0 (DMB)
Setup DE2 PLL
clock_set_pll_de: clk=297000000
PLL10 rate = 24000000 * n / m
  0x1c20048 = 0x81001701 (DMB)
  while (!(readl(0x1c20048) & 0x10000000))
Enable DE2 special clock
  clrsetbits 0x1c20104, 0x3000000, 0x81000000
Enable DE2 ahb
  setbits 0x1c202c4, 0x1000
  setbits 0x1c20064, 0x1000
Enable clock for mixer 0, set route MIXER0->TCON0
  setbits 0x1000000, 0x1
  setbits 0x1000008, 0x1
  setbits 0x1000004, 0x1
  clrbits 0x1000010, 0x1
Clear all registers
  0x1100000 to 0x1105fff = 0x0
  0x1120000 = 0x0
  0x1130000 = 0x0
  0x1140000 = 0x0
  0x1150000 = 0x0
  0x11a0000 = 0x0
  0x11a2000 = 0x0
  0x11a4000 = 0x0
  0x11a6000 = 0x0
  0x11a8000 = 0x0
  0x11aa000 = 0x0
  0x11b0000 = 0x0
Enable mixer
  0x1100000 = 0x1 (DMB)
backlight_enable: pct=0x5a
1.0 has incorrectly documented non-presence of PH10, the circuit is in fact the same as on 1.1+
configure pwm: GPL(10), GPL_R_PWM
sunxi_gpio_set_cfgpin: pin=0x16a, val=2
sunxi_gpio_set_cfgbank: bank_offset=362, val=2
  clrsetbits 0x1f02c04, 0xf00, 0x200
  clrbits 0x1f03800, 0x40 (DMB)
  0x1f03804 = 0x4af0437 (DMB)
  0x1f03800 = 0x5f (DMB)
enable backlight: GPH(10), 1
sunxi_gpio_set_cfgpin: pin=0xea, val=1
sunxi_gpio_set_cfgbank: bank_offset=234, val=1
  clrsetbits 0x1c20900, 0xf00, 0x100
sunxi_gpio_output: pin=0xea, val=1
  before: 0x1c2090c = 0x400
  after: 0x1c2090c = 0x400 (DMB)
test_render
initUiBlender
Configure Blender
  *0x1101088 = 0xff000000
  *0x1101084 = 0x0
initUiChannel
Channel 1: Set Overlay (720 x 1440)
  *0x1103000 = 0xff000405
  *0x1103010 = 0x400fd524
  *0x110300c = 0xb40
  *0x1103004 = 0x59f02cf
  *0x1103088 = 0x59f02cf
  *0x1103008 = 0x0
Channel 1: Set Blender Output
  *0x110108c = 0x59f02cf
  *0x110000c = 0x59f02cf
Channel 1: Set Blender Input Pipe 0 (720 x 1440)
  *0x1101008 = 0x59f02cf
  *0x1101004 = 0xff000000
  *0x110100c = 0x0
  *0x1101090 = 0x3010301
Channel 1: Disable Scaler
  *0x1140000 = 0x0
initUiChannel
Channel 2: Set Overlay (600 x 600)
  *0x1104000 = 0xff000005
  *0x1104010 = 0x404f1d24
  *0x110400c = 0x960
  *0x1104004 = 0x2570257
  *0x1104088 = 0x2570257
  *0x1104008 = 0x0
Channel 2: Set Blender Input Pipe 1 (600 x 600)
  *0x1101018 = 0x2570257
  *0x1101014 = 0xff000000
  *0x110101c = 0x340034
  *0x1101094 = 0x3010301
Channel 2: Disable Scaler
  *0x1150000 = 0x0
initUiChannel
Channel 3: Set Overlay (720 x 1440)
  *0x1105000 = 0x7f000005
  *0x1105010 = 0x40651624
  *0x110500c = 0xb40
  *0x1105004 = 0x59f02cf
  *0x1105088 = 0x59f02cf
  *0x1105008 = 0x0
Channel 3: Set Blender Input Pipe 2 (720 x 1440)
  *0x1101028 = 0x59f02cf
  *0x1101024 = 0xff000000
  *0x110102c = 0x0
  *0x1101098 = 0x3010301
Channel 3: Disable Scaler
  *0x1160000 = 0x0
applySettings
Set BLD Route and BLD FColor Control
  *0x1101080 = 0x321
  *0x1101000 = 0x701
Apply Settings
  *0x1100008 = 0x1
HELLO ZIG ON PINEPHONE!
Testing Compose Short Packet (Without Parameter)...
composeShortPacket: channel=0, cmd=0x5, len=1
Result:
05 11 00 36 
Testing Compose Short Packet (With Parameter)...
composeShortPacket: channel=0, cmd=0x15, len=2
Result:
15 bc 4e 35 
Testing Compose Long Packet...
composeLongPacket: channel=0, cmd=0x39, len=64
Result:
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
nsh> 
nsh> 
```

## Testing Zig Display Engine Driver on QEMU

```text
+ aarch64-none-elf-gcc -v
Using built-in specs.
COLLECT_GCC=aarch64-none-elf-gcc
COLLECT_LTO_WRAPPER=/Applications/ArmGNUToolchain/11.3.rel1/aarch64-none-elf/bin/../libexec/gcc/aarch64-none-elf/11.3.1/lto-wrapper
Target: aarch64-none-elf
Configured with: /Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/src/gcc/configure --target=aarch64-none-elf --prefix=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/install --with-gmp=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-mpfr=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-mpc=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-isl=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --disable-shared --disable-nls --disable-threads --disable-tls --enable-checking=release --enable-languages=c,c++,fortran --with-newlib --with-gnu-as --with-gnu-ld --with-sysroot=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/install/aarch64-none-elf --with-pkgversion='Arm GNU Toolchain 11.3.Rel1' --with-bugurl=https://bugs.linaro.org/
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 11.3.1 20220712 (Arm GNU Toolchain 11.3.Rel1) 
+ zig version
0.10.0-dev.2351+b64a1d5ab
+ build_zig
+ pushd ../pinephone-nuttx
~/gicv2/nuttx/pinephone-nuttx ~/gicv2/nuttx/nuttx
+ git pull
remote: Enumerating objects: 5, done.
remote: Counting objects: 100% (5/5), done.
remote: Compressing objects: 100% (1/1), done.
remote: Total 3 (delta 2), reused 3 (delta 2), pack-reused 0
Unpacking objects: 100% (3/3), done.
From https://github.com/lupyuen/pinephone-nuttx
   4f24434..3bc128f  main       -> origin/main
Updating 4f24434..3bc128f
Fast-forward
 render.zig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
+ zig build-obj --verbose-cimport -target aarch64-freestanding-none -mcpu cortex_a53 -isystem /Users/Luppy/gicv2/nuttx/nuttx/include -I /Users/Luppy/gicv2/nuttx/apps/include render.zig
info(compilation): C import output: zig-cache/o/bdba45dc794911501be5991bbd50b924/cimport.zig
info(compilation): C import output: zig-cache/o/4d99b86faf008804574b7c60caf78668/cimport.zig
+ cp render.o /Users/Luppy/gicv2/nuttx/apps/examples/null/null_main.c.Users.Luppy.gicv2.nuttx.apps.examples.null.o
+ popd
~/gicv2/nuttx/nuttx
+ make -j
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: 'libxx.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[2]: Nothing to be done for 'depend'.
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: 'libboards.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: 'libdrivers.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: 'libmm.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: 'libsched.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: 'libbinfmt.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: 'libfs.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
rm -f /Users/Luppy/gicv2/nuttx/apps/libapps.a
make /Users/Luppy/gicv2/nuttx/apps/libapps.a
make[1]: 'libarch.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: 'libc.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
AR (add): libapps.a    builtin_list.c.Users.Luppy.gicv2.nuttx.apps.builtin.o exec_builtin.c.Users.Luppy.gicv2.nuttx.apps.builtin.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
AR (add): libapps.a        hello_main.c.Users.Luppy.gicv2.nuttx.apps.examples.hello.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
AR (add): libapps.a        null_main.c.Users.Luppy.gicv2.nuttx.apps.examples.null.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
AR (add): libapps.a    nsh_init.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_parse.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_console.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_script.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_system.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_command.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_fscmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_ddcmd.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_proccmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_mmcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_timcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_envcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_syscmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_dbgcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_session.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_fsutils.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_builtin.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_romfsetc.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_mntcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_consolemain.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_printf.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_test.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
AR (add): libapps.a    dummy.c.Users.Luppy.gicv2.nuttx.apps.platform.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
AR (add): libapps.a        nsh_main.c.Users.Luppy.gicv2.nuttx.apps.system.nsh.o sh_main.c.Users.Luppy.gicv2.nuttx.apps.system.nsh.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
AR (add): libapps.a    readline.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o readline_fd.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o readline_common.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
AR (add): libapps.a    system.c.Users.Luppy.gicv2.nuttx.apps.system.system.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
AR (add): libapps.a        getprime_main.c.Users.Luppy.gicv2.nuttx.apps.testing.getprime.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
AR (add): libapps.a    getopt.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o dev_null.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o restart.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sigprocmask.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sighand.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o signest.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o fpu.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o setvbuf.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o tls.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o waitpid.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o cancel.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o cond.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o mutex.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedmutex.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sem.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o semtimed.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o barrier.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedwait.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o pthread_rwlock.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o pthread_rwlock_cancel.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o specific.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o robust.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o roundrobin.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o mqueue.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedmqueue.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o posixtimer.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o vfork.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o    ostest_main.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
IN: /Users/Luppy/gicv2/nuttx/apps/libapps.a -> staging/libapps.a
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards/arm64/qemu/qemu-a53/src'
make[2]: 'libboard.a' is up to date.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards/arm64/qemu/qemu-a53/src'
LD: nuttx
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
CP: nuttx.hex
CP: nuttx.bin
+ aarch64-none-elf-size nuttx
   text    data     bss     dec     hex filename
 273955   12624 9782904 10069483         99a5eb nuttx
+ aarch64-none-elf-objdump -t -S --demangle --line-numbers --wide nuttx
+ qemu-system-aarch64 -smp 4 -cpu cortex-a53 -nographic -machine virt,virtualization=on,gic-version=2 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x40c1d000, heap_size=0x73e3000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x8000000
arm64_gic_initialize: CONFIG_GICR_BASE=0x8010000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 62.50MHz, cycle 62500
up_timer_initialize: _vector_table=0x402b5000
up_timer_initialize: Before writing: vbar_el1=0x402b5000
up_timer_initialize: After writing: vbar_el1=0x402b5000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x402b5000 _einit: 0x402b5000 _stext: 0x40280000 _etext: 0x402b6000
nsh: sysinit: fopen failed: 2
nsh: mkfatfs: command not found

NuttShell (NSH) NuttX-11.0.0-RC2
nsh> nx_start: CPU0: Beginning Idle Loop

nsh> hello
task_spawn: name=hello entry=0x4029b35c file_actions=0x40c22580 attr=0x40c22588 argv=0x40c226d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
Hello, World!!
test_render
initUiBlender
Configure Blender
  *0x1101088 = 0xff000000
  *0x1101084 = 0x0
initUiChannel
Channel 1: Set Overlay (720 x 1440)
  *0x1103000 = 0xff000405
  *0x1103010 = 0x402cf808
  *0x110300c = 0xb40
  *0x1103004 = 0x59f02cf
  *0x1103088 = 0x59f02cf
  *0x1103008 = 0x0
Channel 1: Set Blender Output
  *0x110108c = 0x59f02cf
  *0x110000c = 0x59f02cf
Channel 1: Set Blender Input Pipe 0 (720 x 1440)
  *0x1101008 = 0x59f02cf
  *0x1101004 = 0xff000000
  *0x110100c = 0x0
  *0x1101090 = 0x3010301
Channel 1: Disable Scaler
  *0x1140000 = 0x0
initUiChannel
Channel 2: Set Overlay (600 x 600)
  *0x1104000 = 0xff000005
  *0x1104010 = 0x406c4008
  *0x110400c = 0x960
  *0x1104004 = 0x2570257
  *0x1104088 = 0x2570257
  *0x1104008 = 0x0
Channel 2: Set Blender Input Pipe 1 (600 x 600)
  *0x1101018 = 0x2570257
  *0x1101014 = 0xff000000
  *0x110101c = 0x340034
  *0x1101094 = 0x3010301
Channel 2: Disable Scaler
  *0x1150000 = 0x0
initUiChannel
Channel 3: Set Overlay (720 x 1440)
  *0x1105000 = 0x7f000005
  *0x1105010 = 0x40823908
  *0x110500c = 0xb40
  *0x1105004 = 0x59f02cf
  *0x1105088 = 0x59f02cf
  *0x1105008 = 0x0
Channel 3: Set Blender Input Pipe 2 (720 x 1440)
  *0x1101028 = 0x59f02cf
  *0x1101024 = 0xff000000
  *0x110102c = 0x0
  *0x1101098 = 0x3010301
Channel 3: Disable Scaler
  *0x1160000 = 0x0
applySettings
Set BLD Route and BLD FColor Control
  *0x1101080 = 0x321
  *0x1101000 = 0x701
Apply Settings
  *0x1100008 = 0x1
nsh> qemu-system-aarch64: terminating on signal 2 from pid 93762 (<unknown process>)
 *  Terminal will be reused by tasks, press any key to close it. 
```

## Testing p-boot Display Engine on PinePhone

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
214451 bytes read in 12 ms (17 MiB/s)
Uncompressed size: 10240000 = 0x9C4000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 51 ms (20.2 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x40a44000, heap_size=0x75bc000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400d2000
up_timer_initialize: Before writing: vbar_el1=0x40252000
up_timer_initialize: After writing: vbar_el1=0x400d2000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400d2000 _einit: 0x400d2000 _stext: 0x40080000 _etext: 0x400d3000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> hello
task_spawn: name=hello entry=0x4009d2fc file_actions=0x40a49580 attr=0x40a49588 argv=0x40a496d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
struct reg_inst dsi_init_seq[] = {
.{ 0x0000, 0x00000001 },
.{ 0x0010, 0x00030000 },
.{ 0x0060, 0x0000000a },
.{ 0x0078, 0x00000000 },
.{ 0x0020, 0x0000001f },
.{ 0x0024, 0x10000001 },
.{ 0x0028, 0x20000010 },
.{ 0x002c, 0x2000000f },
.{ 0x0030, 0x30100001 },
.{ 0x0034, 0x40000010 },
.{ 0x0038, 0x0000000f },
.{ 0x003c, 0x5000001f },
.{ 0x004c, 0x00560001 },
.{ 0x02f8, 0x000000ff },
.{ 0x0014, 0x00005bc7 },
.{ 0x007c, 0x10000007 },
.{ 0x0040, 0x30000002 },
.{ 0x0044, 0x00310031 },
.{ 0x0054, 0x00310031 },
.{ 0x0090, 0x1308703e },
.{ 0x0098, 0x0000ffff },
.{ 0x009c, 0xffffffff },
.{ 0x0080, 0x00010008 },
display_malloc: size=2330
.{ 0x000c, 0x00000000 },
.{ 0x00b0, 0x12000021 },
.{ 0x00b4, 0x01000031 },
.{ 0x00b8, 0x07000001 },
.{ 0x00bc, 0x14000011 },
.{ 0x0018, 0x0011000a },
.{ 0x001c, 0x05cd05a0 },
.{ 0x00c0, 0x09004a19 },
.{ 0x00c4, 0x50b40000 },
.{ 0x00c8, 0x35005419 },
.{ 0x00cc, 0x757a0000 },
.{ 0x00d0, 0x09004a19 },
.{ 0x00d4, 0x50b40000 },
.{ 0x00e0, 0x0c091a19 },
.{ 0x00e4, 0x72bd0000 },
.{ 0x00e8, 0x1a000019 },
.{ 0x00ec, 0xffff0000 },
};

Configure Blender
  BLD BkColor: 0x1101088 = 0xff000000
  BLD Premultiply: 0x1101084 = 0x0

Channel 1: Set Overlay
  UI Config Attr: 0x1103000 = 0xff000405
  UI Config Top LAddr: 0x1103010 = 0x4064a6ac
  UI Config Pitch: 0x110300c = 0xb40
  UI Config Size: 0x1103004 = 0x59f02cf
  UI Overlay Size: 0x1103088 = 0x59f02cf
  IO Config Coord: 0x1103008 = 0x0

Channel 1: Set Blender Output
  BLD Output Size: 0x110108c = 0x59f02cf
  GLB Size: 0x110000c = 0x59f02cf

Channel 1: Set Blender Input Pipe 0
  BLD Pipe InSize: 0x1101008 = 0x59f02cf
  BLD Pipe FColor: 0x1101004 = 0xff000000
  BLD Pipe Offset: 0x110100c = 0x0
  BLD Pipe Mode: 0x1101090 = 0x3010301

Channel 1: Disable Scaler
  Mixer: 0x1140000 = 0x0

Channel 2: Set Overlay
  UI Config Attr: 0x1104000 = 0xff000005
  UI Config Top LAddr: 0x1104010 = 0x404eadac
  UI Config Pitch: 0x110400c = 0x960
  UI Config Size: 0x1104004 = 0x2570257
  UI Overlay Size: 0x1104088 = 0x2570257
  IO Config Coord: 0x1104008 = 0x0

Channel 2: Set Blender Input Pipe 1
  BLD Pipe InSize: 0x1101018 = 0x2570257
  BLD Pipe FColor: 0x1101014 = 0xff000000
  BLD Pipe Offset: 0x110101c = 0x340034
  BLD Pipe Mode: 0x1101094 = 0x3010301

Channel 2: Disable Scaler
  Mixer: 0x1150000 = 0x0

Channel 3: Set Overlay
  UI Config Attr: 0x1105000 = 0xff000005
  UI Config Top LAddr: 0x1105010 = 0x400f65ac
  UI Config Pitch: 0x110500c = 0xb40
  UI Config Size: 0x1105004 = 0x59f02cf
  UI Overlay Size: 0x1105088 = 0x59f02cf
  IO Config Coord: 0x1105008 = 0x0

Channel 3: Set Blender Input Pipe 2
  BLD Pipe InSize: 0x1101028 = 0x59f02cf
  BLD Pipe FColor: 0x1101024 = 0xff000000
  BLD Pipe Offset: 0x110102c = 0x0
  BLD Pipe Mode: 0x1101098 = 0x3010301

Channel 3: Disable Scaler
  Mixer: 0x1160000 = 0x0

Set BLD Route and BLD FColor Control
  BLD Route: 0x1101080 = 0x321 (DMB)
  BLD FColor Control: 0x1101000 = 0x701 (DMB)

Apply Settings
  GLB DBuff: 0x1100008 = 0x1 (DMB)
```

If we enable Channel 1 and disable Channels 2 and 3...

```text
display_commit

Configure Blender
  BLD BkColor: 0x1101088 = 0xff000000
  BLD Premultiply: 0x1101084 = 0x0

Channel 1: Set Overlay
  UI Config Attr: 0x1103000 = 0xff000405
  UI Config Top LAddr: 0x1103010 = 0x400f65ac
  UI Config Pitch: 0x110300c = 0xb40
  UI Config Size: 0x1103004 = 0x59f02cf
  UI Overlay Size: 0x1103088 = 0x59f02cf
  IO Config Coord: 0x1103008 = 0x0

Channel 1: Set Blender Output
  BLD Output Size: 0x110108c = 0x59f02cf
  GLB Size: 0x110000c = 0x59f02cf

Channel 1: Set Blender Input Pipe 0
  BLD Pipe InSize: 0x1101008 = 0x59f02cf
  BLD Pipe FColor: 0x1101004 = 0xff000000
  BLD Pipe Offset: 0x110100c = 0x0
  BLD Pipe Mode: 0x1101090 = 0x3010301

Channel 1: Disable Scaler
  Mixer: 0x1140000 = 0x0

Channel 2: Disable Overlay and Pipe
  UI Config Attr: 0x1104000 = 0x0

Channel 2: Disable Scaler
  Mixer: 0x1150000 = 0x0

Channel 3: Disable Overlay and Pipe
  UI Config Attr: 0x1105000 = 0x0

Channel 3: Disable Scaler
  Mixer: 0x1160000 = 0x0

Set BLD Route and BLD FColor Control
  BLD Route: 0x1101080 = 0x1
  BLD FColor Control: 0x1101000 = 0x101

Apply Settings
  GLB DBuff: 0x1100008 = 0x1
```

## Testing NuttX Zig Driver for MIPI DSI on PinePhone

Testing our [NuttX Zig Driver for MIPI DSI](https://github.com/lupyuen/pinephone-nuttx#zig-driver-for-pinephone-mipi-dsi) on PinePhone...

(Screen lights up and shows a test pattern)

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
207379 bytes read in 13 ms (15.2 MiB/s)
Uncompressed size: 4653056 = 0x470000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 50 ms (20.6 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x404f0000, heap_size=0x7b10000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400d2000
up_timer_initialize: Before writing: vbar_el1=0x40252000
up_timer_initialize: After writing: vbar_el1=0x400d2000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400d2000 _einit: 0x400d2000 _stext: 0x40080000 _etext: 0x400d3000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> hello
task_spawn: name=hello entry=0x4009ce64 file_actions=0x404f5580 attr=0x404f5588 argv=0x404f56d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
struct reg_inst dsi_init_seq[] = {
.{ 0x0000, 0x00000001 },
.{ 0x0010, 0x00030000 },
.{ 0x0060, 0x0000000a },
.{ 0x0078, 0x00000000 },
.{ 0x0020, 0x0000001f },
.{ 0x0024, 0x10000001 },
.{ 0x0028, 0x20000010 },
.{ 0x002c, 0x2000000f },
.{ 0x0030, 0x30100001 },
.{ 0x0034, 0x40000010 },
.{ 0x0038, 0x0000000f },
.{ 0x003c, 0x5000001f },
.{ 0x004c, 0x00560001 },
.{ 0x02f8, 0x000000ff },
.{ 0x0014, 0x00005bc7 },
.{ 0x007c, 0x10000007 },
.{ 0x0040, 0x30000002 },
.{ 0x0044, 0x00310031 },
.{ 0x0054, 0x00310031 },
.{ 0x0090, 0x1308703e },
.{ 0x0098, 0x0000ffff },
.{ 0x009c, 0xffffffff },
.{ 0x0080, 0x00010008 },
display_malloc: size=2330
.{ 0x000c, 0x00000000 },
.{ 0x00b0, 0x12000021 },
.{ 0x00b4, 0x01000031 },
.{ 0x00b8, 0x07000001 },
.{ 0x00bc, 0x14000011 },
.{ 0x0018, 0x0011000a },
.{ 0x001c, 0x05cd05a0 },
.{ 0x00c0, 0x09004a19 },
.{ 0x00c4, 0x50b40000 },
.{ 0x00c8, 0x35005419 },
.{ 0x00cc, 0x757a0000 },
.{ 0x00d0, 0x09004a19 },
.{ 0x00d4, 0x50b40000 },
.{ 0x00e0, 0x0c091a19 },
.{ 0x00e4, 0x72bd0000 },
.{ 0x00e8, 0x1a000019 },
.{ 0x00ec, 0xffff0000 },
};

## Testing NuttX Zig Driver for MIPI DSI on QEMU

Testing our [NuttX Zig Driver for MIPI DSI](https://github.com/lupyuen/pinephone-nuttx#zig-driver-for-pinephone-mipi-dsi) on PinePhone...

```text
+ aarch64-none-elf-gcc -v
Using built-in specs.
COLLECT_GCC=aarch64-none-elf-gcc
COLLECT_LTO_WRAPPER=/Applications/ArmGNUToolchain/11.3.rel1/aarch64-none-elf/bin/../libexec/gcc/aarch64-none-elf/11.3.1/lto-wrapper
Target: aarch64-none-elf
Configured with: /Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/src/gcc/configure --target=aarch64-none-elf --prefix=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/install --with-gmp=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-mpfr=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-mpc=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --with-isl=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/host-tools --disable-shared --disable-nls --disable-threads --disable-tls --enable-checking=release --enable-languages=c,c++,fortran --with-newlib --with-gnu-as --with-gnu-ld --with-sysroot=/Volumes/data/jenkins/workspace/GNU-toolchain/arm-11/build-aarch64-none-elf/install/aarch64-none-elf --with-pkgversion='Arm GNU Toolchain 11.3.Rel1' --with-bugurl=https://bugs.linaro.org/
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 11.3.1 20220712 (Arm GNU Toolchain 11.3.Rel1) 
+ zig version
0.10.0-dev.2351+b64a1d5ab
+ build_zig
+ pushd ../pinephone-nuttx
~/gicv2/nuttx/pinephone-nuttx ~/gicv2/nuttx/nuttx
+ git pull
Already up-to-date.
+ zig build-obj -target aarch64-freestanding-none -mcpu cortex_a53 -isystem /Users/Luppy/gicv2/nuttx/nuttx/include -I /Users/Luppy/gicv2/nuttx/apps/include display.zig
+ cp display.o /Users/Luppy/gicv2/nuttx/apps/examples/null/null_main.c.Users.Luppy.gicv2.nuttx.apps.examples.null.o
+ popd
~/gicv2/nuttx/nuttx
+ make -j
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: 'libxx.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[2]: Nothing to be done for 'depend'.
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[2]: Nothing to be done for 'depend'.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: Nothing to be done for 'depend'.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libxx'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
make[1]: 'libboards.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards'
make[1]: 'libdrivers.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/drivers'
make[1]: 'libmm.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/mm'
make[1]: 'libsched.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/sched'
make[1]: 'libfs.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/fs'
make[1]: 'libbinfmt.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/binfmt'
rm -f /Users/Luppy/gicv2/nuttx/apps/libapps.a
make /Users/Luppy/gicv2/nuttx/apps/libapps.a
make[1]: 'libarch.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: 'libc.a' is up to date.
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/libs/libc'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Nothing to be done for 'all'.
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
AR (add): libapps.a    builtin_list.c.Users.Luppy.gicv2.nuttx.apps.builtin.o exec_builtin.c.Users.Luppy.gicv2.nuttx.apps.builtin.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/builtin'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
AR (add): libapps.a        hello_main.c.Users.Luppy.gicv2.nuttx.apps.examples.hello.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/hello'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
AR (add): libapps.a        null_main.c.Users.Luppy.gicv2.nuttx.apps.examples.null.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/examples/null'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
AR (add): libapps.a    nsh_init.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_parse.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_console.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_script.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_system.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_command.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_fscmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_ddcmd.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_proccmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_mmcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_timcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_envcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_syscmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_dbgcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_session.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_fsutils.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_builtin.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_romfsetc.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_mntcmds.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_consolemain.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_printf.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o nsh_test.c.Users.Luppy.gicv2.nuttx.apps.nshlib.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/nshlib'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/platform'
AR (add): libapps.a    dummy.c.Users.Luppy.gicv2.nuttx.apps.platform.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/platform'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
AR (add): libapps.a        nsh_main.c.Users.Luppy.gicv2.nuttx.apps.system.nsh.o sh_main.c.Users.Luppy.gicv2.nuttx.apps.system.nsh.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/nsh'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
AR (add): libapps.a    readline.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o readline_fd.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o readline_common.c.Users.Luppy.gicv2.nuttx.apps.system.readline.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/readline'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
AR (add): libapps.a    system.c.Users.Luppy.gicv2.nuttx.apps.system.system.o       
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/system/system'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
AR (add): libapps.a        getprime_main.c.Users.Luppy.gicv2.nuttx.apps.testing.getprime.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/getprime'
make[3]: Entering directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
AR (add): libapps.a    getopt.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o dev_null.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o restart.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sigprocmask.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sighand.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o signest.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o fpu.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o setvbuf.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o tls.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o waitpid.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o cancel.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o cond.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o mutex.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedmutex.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o sem.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o semtimed.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o barrier.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedwait.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o pthread_rwlock.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o pthread_rwlock_cancel.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o specific.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o robust.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o roundrobin.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o mqueue.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o timedmqueue.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o posixtimer.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o vfork.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o    ostest_main.c.Users.Luppy.gicv2.nuttx.apps.testing.ostest.o   
make[3]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps/testing/ostest'
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/apps'
IN: /Users/Luppy/gicv2/nuttx/apps/libapps.a -> staging/libapps.a
make[1]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
make[2]: Entering directory '/Users/Luppy/gicv2/nuttx/nuttx/boards/arm64/qemu/qemu-a53/src'
make[2]: 'libboard.a' is up to date.
make[2]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/boards/arm64/qemu/qemu-a53/src'
LD: nuttx
make[1]: Leaving directory '/Users/Luppy/gicv2/nuttx/nuttx/arch/arm64/src'
CP: nuttx.hex
CP: nuttx.bin
+ aarch64-none-elf-size nuttx
   text    data     bss     dec     hex filename
 253075   12624   48504  314203   4cb5b nuttx
+ aarch64-none-elf-objdump -t -S --demangle --line-numbers --wide nuttx
+ qemu-system-aarch64 -smp 4 -cpu cortex-a53 -nographic -machine virt,virtualization=on,gic-version=2 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x402cf000, heap_size=0x7d31000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x8000000
arm64_gic_initialize: CONFIG_GICR_BASE=0x8010000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 62.50MHz, cycle 62500
up_timer_initialize: _vector_table=0x402b1000
up_timer_initialize: Before writing: vbar_el1=0x402b1000
up_timer_initialize: After writing: vbar_el1=0x402b1000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x402b1000 _einit: 0x402b1000 _stext: 0x40280000 _etext: 0x402b2000
nsh: sysinit: fopen failed: 2
nsh: mkfatfs: command not found

NuttShell (NSH) NuttX-11.0.0-RC2
nsh> nx_start: CPU0: Beginning Idle Loop

nsh> null
task_spawn: name=null entry=0x4029c9d0 file_actions=0x402d4580 attr=0x402d4588 argv=0x402d46d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
HELLO ZIG ON PINEPHONE!
Testing Compose Short Packet (Without Parameter)...
composeShortPacket: channel=0, cmd=0x5, len=1
Result:
05 11 00 36 
Testing Compose Short Packet (With Parameter)...
composeShortPacket: channel=0, cmd=0x15, len=2
Result:
15 bc 4e 35 
Testing Compose Long Packet...
composeLongPacket: channel=0, cmd=0x39, len=64
Result:
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
nsh> qemu-system-aarch64: terminating on signal 2 from pid 5928 (<unknown process>)
 *  Terminal will be reused by tasks, press any key to close it. 
```

## Testing p-boot Driver for MIPI DSI (with logging)

Testing [PinePhone p-boot Display Code](https://gist.github.com/lupyuen/ee3adf76e76881609845d0ab0f768a95) with logging...

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
205024 bytes read in 13 ms (15 MiB/s)
Uncompressed size: 4640768 = 0x46D000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 51 ms (20.2 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x404ed000, heap_size=0x7b13000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400cf000
up_timer_initialize: Before writing: vbar_el1=0x4024f000
up_timer_initialize: After writing: vbar_el1=0x400cf000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400cf000 _einit: 0x400cf000 _stext: 0x40080000 _etext: 0x400d0000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> hello
task_spawn: name=hello entry=0x4009cf58 file_actions=0x404f2580 attr=0x404f2588 argv=0x404f26d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
struct reg_inst dsi_init_seq[] = {
.{ 0x0000, 0x00000001 },
.{ 0x0010, 0x00030000 },
.{ 0x0060, 0x0000000a },
.{ 0x0078, 0x00000000 },
.{ 0x0020, 0x0000001f },
.{ 0x0024, 0x10000001 },
.{ 0x0028, 0x20000010 },
.{ 0x002c, 0x2000000f },
.{ 0x0030, 0x30100001 },
.{ 0x0034, 0x40000010 },
.{ 0x0038, 0x0000000f },
.{ 0x003c, 0x5000001f },
.{ 0x004c, 0x00560001 },
.{ 0x02f8, 0x000000ff },
.{ 0x0014, 0x00005bc7 },
.{ 0x007c, 0x10000007 },
.{ 0x0040, 0x30000002 },
.{ 0x0044, 0x00310031 },
.{ 0x0054, 0x00310031 },
.{ 0x0090, 0x1308703e },
.{ 0x0098, 0x0000ffff },
.{ 0x009c, 0xffffffff },
.{ 0x0080, 0x00010008 },
display_malloc: size=2330
.{ 0x000c, 0x00000000 },
.{ 0x00b0, 0x12000021 },
.{ 0x00b4, 0x01000031 },
.{ 0x00b8, 0x07000001 },
.{ 0x00bc, 0x14000011 },
.{ 0x0018, 0x0011000a },
.{ 0x001c, 0x05cd05a0 },
.{ 0x00c0, 0x09004a19 },
.{ 0x00c4, 0x50b40000 },
.{ 0x00c8, 0x35005419 },
.{ 0x00cc, 0x757a0000 },
.{ 0x00d0, 0x09004a19 },
.{ 0x00d4, 0x50b40000 },
.{ 0x00e0, 0x0c091a19 },
.{ 0x00e4, 0x72bd0000 },
.{ 0x00e8, 0x1a000019 },
.{ 0x00ec, 0xffff0000 },
};

struct reg_inst dsi_panel_init_seq[] = {
mipi_dsi_dcs_write: long len=4
b9 f1 12 83 
.{ 0x0300, 0x2c000439 },
header: 2c000439
display_zalloc: size=10
.{ 0x0304, 0x8312f1b9 },
.{ 0x0308, 0x00005d84 },
payload[0]: 8312f1b9
payload[1]: 00005d84
.{ 0x0200, 0x00000009 },
len: 9
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=28
ba 33 81 05 f9 0e 0e 20 
00 00 00 00 00 00 00 44 
25 00 91 0a 00 00 02 4f 
11 00 00 37 
.{ 0x0300, 0x2f001c39 },
header: 2f001c39
display_zalloc: size=34
.{ 0x0304, 0x058133ba },
.{ 0x0308, 0x200e0ef9 },
.{ 0x030c, 0x00000000 },
.{ 0x0310, 0x44000000 },
.{ 0x0314, 0x0a910025 },
.{ 0x0318, 0x4f020000 },
.{ 0x031c, 0x37000011 },
.{ 0x0320, 0x0000e22c },
payload[0]: 058133ba
payload[1]: 200e0ef9
payload[2]: 00000000
payload[3]: 44000000
payload[4]: 0a910025
payload[5]: 4f020000
payload[6]: 37000011
payload[7]: 0000e22c
.{ 0x0200, 0x00000021 },
len: 33
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=5
b8 25 22 20 03 
.{ 0x0300, 0x36000539 },
header: 36000539
display_zalloc: size=11
.{ 0x0304, 0x202225b8 },
.{ 0x0308, 0x00720303 },
payload[0]: 202225b8
payload[1]: 00720303
.{ 0x0200, 0x0000000a },
len: 10
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=11
b3 10 10 05 05 03 ff 00 
00 00 00 
.{ 0x0300, 0x2c000b39 },
header: 2c000b39
display_zalloc: size=17
.{ 0x0304, 0x051010b3 },
.{ 0x0308, 0x00ff0305 },
.{ 0x030c, 0x6f000000 },
.{ 0x0310, 0x000000bc },
payload[0]: 051010b3
payload[1]: 00ff0305
payload[2]: 6f000000
payload[3]: 000000bc
.{ 0x0200, 0x00000010 },
len: 16
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=10
c0 73 73 50 50 00 c0 08 
70 00 
.{ 0x0300, 0x36000a39 },
header: 36000a39
display_zalloc: size=16
.{ 0x0304, 0x507373c0 },
.{ 0x0308, 0x08c00050 },
.{ 0x030c, 0x6a1b0070 },
payload[0]: 507373c0
payload[1]: 08c00050
payload[2]: 6a1b0070
.{ 0x0200, 0x0000000f },
len: 15
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: short len=2
bc 4e 
.{ 0x0300, 0x354ebc15 },
header: 354ebc15
.{ 0x0200, 0x00000003 },
len: 3
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: short len=2
cc 0b 
.{ 0x0300, 0x220bcc15 },
header: 220bcc15
.{ 0x0200, 0x00000003 },
len: 3
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: short len=2
b4 80 
.{ 0x0300, 0x2280b415 },
header: 2280b415
.{ 0x0200, 0x00000003 },
len: 3
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=4
b2 f0 12 f0 
.{ 0x0300, 0x2c000439 },
header: 2c000439
display_zalloc: size=10
.{ 0x0304, 0xf012f0b2 },
.{ 0x0308, 0x00008651 },
payload[0]: f012f0b2
payload[1]: 00008651
.{ 0x0200, 0x00000009 },
len: 9
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=15
e3 00 00 0b 0b 10 10 00 
00 00 00 ff 00 c0 10 
.{ 0x0300, 0x0f000f39 },
header: 0f000f39
display_zalloc: size=21
.{ 0x0304, 0x0b0000e3 },
.{ 0x0308, 0x0010100b },
.{ 0x030c, 0xff000000 },
.{ 0x0310, 0x3610c000 },
.{ 0x0314, 0x0000000f },
payload[0]: 0b0000e3
payload[1]: 0010100b
payload[2]: ff000000
payload[3]: 3610c000
payload[4]: 0000000f
.{ 0x0200, 0x00000014 },
len: 20
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=6
c6 01 00 ff ff 00 
.{ 0x0300, 0x30000639 },
header: 30000639
display_zalloc: size=12
.{ 0x0304, 0xff0001c6 },
.{ 0x0308, 0x258e00ff },
payload[0]: ff0001c6
payload[1]: 258e00ff
.{ 0x0200, 0x0000000b },
len: 11
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=13
c1 74 00 32 32 77 f1 ff 
ff cc cc 77 77 
.{ 0x0300, 0x13000d39 },
header: 13000d39
display_zalloc: size=19
.{ 0x0304, 0x320074c1 },
.{ 0x0308, 0xfff17732 },
.{ 0x030c, 0x77ccccff },
.{ 0x0310, 0x00e46977 },
payload[0]: 320074c1
payload[1]: fff17732
payload[2]: 77ccccff
payload[3]: 00e46977
.{ 0x0200, 0x00000012 },
len: 18
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=3
b5 07 07 
.{ 0x0300, 0x09000339 },
header: 09000339
display_zalloc: size=9
.{ 0x0304, 0x7b0707b5 },
.{ 0x0308, 0x000000b3 },
payload[0]: 7b0707b5
payload[1]: 000000b3
.{ 0x0200, 0x00000008 },
len: 8
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=3
b6 2c 2c 
.{ 0x0300, 0x09000339 },
header: 09000339
display_zalloc: size=9
.{ 0x0304, 0x552c2cb6 },
.{ 0x0308, 0x00000004 },
payload[0]: 552c2cb6
payload[1]: 00000004
.{ 0x0200, 0x00000008 },
len: 8
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=4
bf 02 11 00 
.{ 0x0300, 0x2c000439 },
header: 2c000439
display_zalloc: size=10
.{ 0x0304, 0x001102bf },
.{ 0x0308, 0x0000e9b5 },
payload[0]: 001102bf
payload[1]: 0000e9b5
.{ 0x0200, 0x00000009 },
len: 9
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=64
e9 82 10 06 05 a2 0a a5 
12 31 23 37 83 04 bc 27 
38 0c 00 03 00 00 00 0c 
00 03 00 00 00 75 75 31 
88 88 88 88 88 88 13 88 
64 64 20 88 88 88 88 88 
88 02 88 00 00 00 00 00 
00 00 00 00 00 00 00 00

.{ 0x0300, 0x25004039 },
header: 25004039
display_zalloc: size=70
.{ 0x0304, 0x061082e9 },
.{ 0x0308, 0xa50aa205 },
.{ 0x030c, 0x37233112 },
.{ 0x0310, 0x27bc0483 },
.{ 0x0314, 0x03000c38 },
.{ 0x0318, 0x0c000000 },
.{ 0x031c, 0x00000300 },
.{ 0x0320, 0x31757500 },
.{ 0x0324, 0x88888888 },
.{ 0x0328, 0x88138888 },
.{ 0x032c, 0x88206464 },
.{ 0x0330, 0x88888888 },
.{ 0x0334, 0x00880288 },
.{ 0x0338, 0x00000000 },
.{ 0x033c, 0x00000000 },
.{ 0x0340, 0x00000000 },
.{ 0x0344, 0x00000365 },
payload[0]: 061082e9
payload[1]: a50aa205
payload[2]: 37233112
payload[3]: 27bc0483
payload[4]: 03000c38
payload[5]: 0c000000
payload[6]: 00000300
payload[7]: 31757500
payload[8]: 88888888
payload[9]: 88138888
payload[10]: 88206464
payload[11]: 88888888
payload[12]: 00880288
payload[13]: 00000000
payload[14]: 00000000
payload[15]: 00000000
payload[16]: 00000365
.{ 0x0200, 0x00000045 },
len: 69
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=62
ea 02 21 00 00 00 00 00 
00 00 00 00 00 02 46 02 
88 88 88 88 88 88 64 88 
13 57 13 88 88 88 88 88 
88 75 88 23 14 00 00 02 
00 00 00 00 00 00 00 00 
00 00 00 00 00 00 00 03 
0a a5 00 00 00 00 
.{ 0x0300, 0x1a003e39 },
header: 1a003e39
display_zalloc: size=68
.{ 0x0304, 0x002102ea },
.{ 0x0308, 0x00000000 },
.{ 0x030c, 0x00000000 },
.{ 0x0310, 0x02460200 },
.{ 0x0314, 0x88888888 },
.{ 0x0318, 0x88648888 },
.{ 0x031c, 0x88135713 },
.{ 0x0320, 0x88888888 },
.{ 0x0324, 0x23887588 },
.{ 0x0328, 0x02000014 },
.{ 0x032c, 0x00000000 },
.{ 0x0330, 0x00000000 },
.{ 0x0334, 0x00000000 },
.{ 0x0338, 0x03000000 },
.{ 0x033c, 0x0000a50a },
.{ 0x0340, 0x1b240000 },
payload[0]: 002102ea
payload[1]: 00000000
payload[2]: 00000000
payload[3]: 02460200
payload[4]: 88888888
payload[5]: 88648888
payload[6]: 88135713
payload[7]: 88888888
payload[8]: 23887588
payload[9]: 02000014
payload[10]: 00000000
payload[11]: 00000000
payload[12]: 00000000
payload[13]: 03000000
payload[14]: 0000a50a
payload[15]: 1b240000
.{ 0x0200, 0x00000043 },
len: 67
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: long len=35
e0 00 09 0d 23 27 3c 41 
35 07 0d 0e 12 13 10 12 
12 18 00 09 0d 23 27 3c 
41 35 07 0d 0e 12 13 10 
12 12 18 
.{ 0x0300, 0x20002339 },
header: 20002339
display_zalloc: size=41
.{ 0x0304, 0x0d0900e0 },
.{ 0x0308, 0x413c2723 },
.{ 0x030c, 0x0e0d0735 },
.{ 0x0310, 0x12101312 },
.{ 0x0314, 0x09001812 },
.{ 0x0318, 0x3c27230d },
.{ 0x031c, 0x0d073541 },
.{ 0x0320, 0x1013120e },
.{ 0x0324, 0x93181212 },
.{ 0x0328, 0x000000bf },
payload[0]: 0d0900e0
payload[1]: 413c2723
payload[2]: 0e0d0735
payload[3]: 12101312
payload[4]: 09001812
payload[5]: 3c27230d
payload[6]: 0d073541
payload[7]: 1013120e
payload[8]: 93181212
payload[9]: 000000bf
.{ 0x0200, 0x00000028 },
len: 40
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: short len=1
11 
.{ 0x0300, 0x36001105 },
header: 36001105
.{ 0x0200, 0x00000003 },
len: 3
.{ MAGIC_COMMIT, 0 },
mipi_dsi_dcs_write: short len=1
29 
.{ 0x0300, 0x1c002905 },
header: 1c002905
.{ 0x0200, 0x00000003 },
len: 3
.{ MAGIC_COMMIT, 0 },
};
.{ 0x0048, 0x00000f02 },
.{ MAGIC_COMMIT, 0 },
dsi_update_bits: 0x01ca0020 : 0000001f -> (00000010) 00000000
.{ 0x0048, 0x63f07006 },
.{ MAGIC_COMMIT, 0 },
HELLO ZIG ON PINEPHONE!
mipi_dsi_dcs_write: channel=0, cmd=0x39, len=64
composeLongPacket: channel=0, cmd=0x39, len=64
computeCrc: len=64, crc=0x365
e9 82 10 06 05 a2 0a a5 
12 31 23 37 83 04 bc 27 
38 0c 00 03 00 00 00 0c 
00 03 00 00 00 75 75 31 
88 88 88 88 88 88 13 88 
64 64 20 88 88 88 88 88 
88 02 88 00 00 00 00 00 
00 00 00 00 00 00 00 00

packet: len=70
39 40 00 25 e9 82 10 06 
05 a2 0a a5 12 31 23 37 
83 04 bc 27 38 0c 00 03 
00 00 00 0c 00 03 00 00 
00 75 75 31 88 88 88 88 
88 88 13 88 64 64 20 88 
88 88 88 88 88 02 88 00 
00 00 00 00 00 00 00 00 
00 00 00 00 65 03 
modifyreg32: addr=0x300, val=0x25004039
modifyreg32: addr=0x304, val=0x061082e9
modifyreg32: addr=0x308, val=0xa50aa205
modifyreg32: addr=0x30c, val=0x37233112
modifyreg32: addr=0x310, val=0x27bc0483
modifyreg32: addr=0x314, val=0x03000c38
modifyreg32: addr=0x318, val=0x0c000000
modifyreg32: addr=0x31c, val=0x00000300
modifyreg32: addr=0x320, val=0x31757500
modifyreg32: addr=0x324, val=0x88888888
modifyreg32: addr=0x328, val=0x88138888
modifyreg32: addr=0x32c, val=0x88206464
modifyreg32: addr=0x330, val=0x88888888
modifyreg32: addr=0x334, val=0x00880288
modifyreg32: addr=0x338, val=0x00000000
modifyreg32: addr=0x33c, val=0x00000000
modifyreg32: addr=0x340, val=0x00000000
modifyreg32: addr=0x344, val=0x00000365
modifyreg32: addr=0x200, val=0x00000045
nsh> 
nsh> 
```

## Testing p-boot Driver for MIPI DSI (without logging)

Testing [PinePhone p-boot Display Code](https://gist.github.com/lupyuen/ee3adf76e76881609845d0ab0f768a95) without logging...

```text
nsh> hello
task_spawn: name=hello entry=0x4009ce04 file_actions=0x404ea580 attr=0x404ea588 argv=0x404ea6d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
ABHello, World!!
ph_cfg1_reg=0x7177
ph_data_reg=0x400
pd_cfg2_reg=0x77711177
pd_data_reg=0x1c0000
struct reg_inst dsi_init_seq[] = {
{ 0x0000, 0x00000001 },
{ 0x0010, 0x00030000 },
{ 0x0060, 0x0000000a },
{ 0x0078, 0x00000000 },
{ 0x0020, 0x0000001f },
{ 0x0024, 0x10000001 },
{ 0x0028, 0x20000010 },
{ 0x002c, 0x2000000f },
{ 0x0030, 0x30100001 },
{ 0x0034, 0x40000010 },
{ 0x0038, 0x0000000f },
{ 0x003c, 0x5000001f },
{ 0x004c, 0x00560001 },
{ 0x02f8, 0x000000ff },
{ 0x0014, 0x00005bc7 },
{ 0x007c, 0x10000007 },
{ 0x0040, 0x30000002 },
{ 0x0044, 0x00310031 },
{ 0x0054, 0x00310031 },
{ 0x0090, 0x1308703e },
{ 0x0098, 0x0000ffff },
{ 0x009c, 0xffffffff },
{ 0x0080, 0x00010008 },
display_malloc: size=2330
{ 0x000c, 0x00000000 },
{ 0x00b0, 0x12000021 },
{ 0x00b4, 0x01000031 },
{ 0x00b8, 0x07000001 },
{ 0x00bc, 0x14000011 },
{ 0x0018, 0x0011000a },
{ 0x001c, 0x05cd05a0 },
{ 0x00c0, 0x09004a19 },
{ 0x00c4, 0x50b40000 },
{ 0x00c8, 0x35005419 },
{ 0x00cc, 0x757a0000 },
{ 0x00d0, 0x09004a19 },
{ 0x00d4, 0x50b40000 },
{ 0x00e0, 0x0c091a19 },
{ 0x00e4, 0x72bd0000 },
{ 0x00e8, 0x1a000019 },
{ 0x00ec, 0xffff0000 },
};

struct reg_inst dsi_panel_init_seq[] = {
{ 0x0300, 0x2c000439 },
display_zalloc: size=10
{ 0x0304, 0x8312f1b9 },
{ 0x0308, 0x00005d84 },
{ 0x0200, 0x00000009 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x2f001c39 },
display_zalloc: size=34
{ 0x0304, 0x058133ba },
{ 0x0308, 0x200e0ef9 },
{ 0x030c, 0x00000000 },
{ 0x0310, 0x44000000 },
{ 0x0314, 0x0a910025 },
{ 0x0318, 0x4f020000 },
{ 0x031c, 0x37000011 },
{ 0x0320, 0x0000e22c },
{ 0x0200, 0x00000021 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x36000539 },
display_zalloc: size=11
{ 0x0304, 0x202225b8 },
{ 0x0308, 0x00720303 },
{ 0x0200, 0x0000000a },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x2c000b39 },
display_zalloc: size=17
{ 0x0304, 0x051010b3 },
{ 0x0308, 0x00ff0305 },
{ 0x030c, 0x6f000000 },
{ 0x0310, 0x000000bc },
{ 0x0200, 0x00000010 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x36000a39 },
display_zalloc: size=16
{ 0x0304, 0x507373c0 },
{ 0x0308, 0x08c00050 },
{ 0x030c, 0x6a1b0070 },
{ 0x0200, 0x0000000f },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x354ebc15 },
{ 0x0200, 0x00000003 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x220bcc15 },
{ 0x0200, 0x00000003 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x2280b415 },
{ 0x0200, 0x00000003 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x2c000439 },
display_zalloc: size=10
{ 0x0304, 0xf012f0b2 },
{ 0x0308, 0x00008651 },
{ 0x0200, 0x00000009 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x0f000f39 },
display_zalloc: size=21
{ 0x0304, 0x0b0000e3 },
{ 0x0308, 0x0010100b },
{ 0x030c, 0xff000000 },
{ 0x0310, 0x3610c000 },
{ 0x0314, 0x0000000f },
{ 0x0200, 0x00000014 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x30000639 },
display_zalloc: size=12
{ 0x0304, 0xff0001c6 },
{ 0x0308, 0x258e00ff },
{ 0x0200, 0x0000000b },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x13000d39 },
display_zalloc: size=19
{ 0x0304, 0x320074c1 },
{ 0x0308, 0xfff17732 },
{ 0x030c, 0x77ccccff },
{ 0x0310, 0x00e46977 },
{ 0x0200, 0x00000012 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x09000339 },
display_zalloc: size=9
{ 0x0304, 0x7b0707b5 },
{ 0x0308, 0x000000b3 },
{ 0x0200, 0x00000008 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x09000339 },
display_zalloc: size=9
{ 0x0304, 0x552c2cb6 },
{ 0x0308, 0x00000004 },
{ 0x0200, 0x00000008 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x2c000439 },
display_zalloc: size=10
{ 0x0304, 0x001102bf },
{ 0x0308, 0x0000e9b5 },
{ 0x0200, 0x00000009 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x25004039 },
display_zalloc: size=70
{ 0x0304, 0x061082e9 },
{ 0x0308, 0xa50aa205 },
{ 0x030c, 0x37233112 },
{ 0x0310, 0x27bc0483 },
{ 0x0314, 0x03000c38 },
{ 0x0318, 0x0c000000 },
{ 0x031c, 0x00000300 },
{ 0x0320, 0x31757500 },
{ 0x0324, 0x88888888 },
{ 0x0328, 0x88138888 },
{ 0x032c, 0x88206464 },
{ 0x0330, 0x88888888 },
{ 0x0334, 0x00880288 },
{ 0x0338, 0x00000000 },
{ 0x033c, 0x00000000 },
{ 0x0340, 0x00000000 },
{ 0x0344, 0x00000365 },
{ 0x0200, 0x00000045 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x1a003e39 },
display_zalloc: size=68
{ 0x0304, 0x002102ea },
{ 0x0308, 0x00000000 },
{ 0x030c, 0x00000000 },
{ 0x0310, 0x02460200 },
{ 0x0314, 0x88888888 },
{ 0x0318, 0x88648888 },
{ 0x031c, 0x88135713 },
{ 0x0320, 0x88888888 },
{ 0x0324, 0x23887588 },
{ 0x0328, 0x02000014 },
{ 0x032c, 0x00000000 },
{ 0x0330, 0x00000000 },
{ 0x0334, 0x00000000 },
{ 0x0338, 0x03000000 },
{ 0x033c, 0x0000a50a },
{ 0x0340, 0x1b240000 },
{ 0x0200, 0x00000043 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x20002339 },
display_zalloc: size=41
{ 0x0304, 0x0d0900e0 },
{ 0x0308, 0x413c2723 },
{ 0x030c, 0x0e0d0735 },
{ 0x0310, 0x12101312 },
{ 0x0314, 0x09001812 },
{ 0x0318, 0x3c27230d },
{ 0x031c, 0x0d073541 },
{ 0x0320, 0x1013120e },
{ 0x0324, 0x93181212 },
{ 0x0328, 0x000000bf },
{ 0x0200, 0x00000028 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x36001105 },
{ 0x0200, 0x00000003 },
{ MAGIC_COMMIT, 0 },
{ 0x0300, 0x1c002905 },
{ 0x0200, 0x00000003 },
{ MAGIC_COMMIT, 0 },
};
{ 0x0048, 0x00000f02 },
{ MAGIC_COMMIT, 0 },
dsi_update_bits: 0x01ca0020 : 0000001f -> (00000010) 00000000
{ 0x0048, 0x63f07006 },
{ MAGIC_COMMIT, 0 },
nsh> 
```

## Testing Zig on PinePhone

U-Boot 2020.07 (Nov 08 2020 - 00:15:12 +0100)

starting USB...
No working controllers found
Hit any key to stop autoboot:  0 
switch to partitions #0, OK
mmc0 is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
653 bytes read in 3 ms (211.9 KiB/s)
## Executing script at 4fc00000
gpio: pin 114 (gpio 114) value is 1
200596 bytes read in 12 ms (15.9 MiB/s)
Uncompressed size: 4624384 = 0x469000
36162 bytes read in 4 ms (8.6 MiB/s)
1078500 bytes read in 50 ms (20.6 MiB/s)
## Flattened Device Tree blob at 4fa00000
   Booting using the fdt blob at 0x4fa00000
   Loading Ramdisk to 49ef8000, end 49fff4e4 ... OK
   Loading Device Tree to 0000000049eec000, end 0000000049ef7d41 ... OK

Starting kernel ...

HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x404e9000, heap_size=0x7b17000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x1c81000
arm64_gic_initialize: CONFIG_GICR_BASE=0x1c82000
arm64_gic_initialize: GIC Version is 2
up_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
up_timer_initialize: _vector_table=0x400cc000
up_timer_initialize: Before writing: vbar_el1=0x4024c000
up_timer_initialize: After writing: vbar_el1=0x400cc000
uart_register: Registering /dev/console
uart_register: Registering /dev/ttyS0
work_start_highpri: Starting high-priority kernel worker thread(s)
nx_start_application: Starting init thread
lib_cxx_initialize: _sinit: 0x400cc000 _einit: 0x400cc000 _stext: 0x40080000 _etext: 0x400cd000
nsh: sysinit: fopen failed: 2
nshn:x _msktfaarttf:s :C PcUo0m:m aBnedg innonti nfgo uInddl
e
 
L
oNoupt
t
Shell (NSH) NuttX-11.0.0-RC2
nsh> null
task_spawn: name=null entry=0x4009d340 file_actions=0x404ee580 attr=0x404ee588 argv=0x404ee6d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
HELLO ZIG ON PINEPHONE!
mipi_dsi_dcs_write: channel=0, cmd=29, len=0

!ZIG PANIC!
nuttx_mipi_dsi_dcs_write not implemented™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™™
Stack Trace:
0x4009d7d4
0x4009d340
0x4009d2f4
0x4009d39c
0x4009d358
0x400852fc
nsh> 
nsh> 
```

## Testing GIC Version 2 on PinePhone

Builtin Apps:
  getprime  hello     nsh       ostest    sh        
nsh> hello
task_spawn: name=hello entry=0x4009b1a0 file_actions=0x400c9580 attr=0x400c9588 argv=0x400c96d0
spawn_execattrs: Setting policy=2 priority=100 for pid=3
Hello, World!!
nsh> ls /dev
/dev:
 console
 null
 ram0
 ram2
 ttyS0
 zero
nsh> 
[7mReally kill this window [y/n][27m
nsh>
```

## Testing GIC Version 2 on QEMU

```text
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x402c4000, heap_size=0x7d3c000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: CONFIG_GICD_BASE=0x8000000
arm64_gic_initialize: CONFIG_GICR_BASE=0x8010000
arm64_gic_initialize: GIC Version is 2
EFGHup_timer_initialize: up_timer_initialize: cp15 timer(s) running at 62.50MHz, cycle 62500
up_timer_initialize: ARM_ARCH_TIMER_IRQ=27
up_timer_initialize: arm64_arch_timer_compare_isr=0x4029b2ac
up_timer_initialize: irq_unexpected_isr=0x402823ec
up_timer_initialize: g_irqvector[0].handler=0x402823ec
up_timer_initialize: g_irqvector[1].handler=0x402823ec
up_timer_initialize: g_irqvector[2].handler=0x402823ec
up_timer_initialize: g_irqvector[3].handler=0x402823ec
up_timer_initialize: g_irqvector[4].handler=0x402823ec
up_timer_initialize: g_irqvector[5].handler=0x402823ec
up_timer_initialize: g_irqvector[6].handler=0x402823ec
up_timer_initialize: g_irqvector[7].handler=0x402823ec
up_timer_initialize: g_irqvector[8].handler=0x402823ec
up_timer_initialize: g_irqvector[9].handler=0x402823ec
up_timer_initialize: g_irqvector[10].handler=0x402823ec
up_timer_initialize: g_irqvector[11].handler=0x402823ec
up_timer_initialize: g_irqvector[12].handler=0x402823ec
up_timer_initialize: g_irqvector[13].handler=0x402823ec
up_timer_initialize: g_irqvector[14].handler=0x402823ec
up_timer_initialize: g_irqvector[15].handler=0x402823ec
up_timer_initialize: g_irqvector[16].handler=0x402823ec
up_timer_initialize: g_irqvector[17].handler=0x402823ec
up_timer_initialize: g_irqvector[18].handler=0x402823ec
up_timer_initialize: g_irqvector[19].handler=0x402823ec
up_timer_initialize: g_irqvector[20].handler=0x402823ec
up_timer_initialize: g_irqvector[21].handler=0x402823ec
up_timer_initialize: g_irqvector[22].handler=0x402823ec
up_timer_initialize: g_irqvector[23].handler=0x402823ec
up_timer_initialize: g_irqvector[24].handler=0x402823ec
up_timer_initialize: g_irqvector[25].handler=0x402823ec
up_timer_initialize: g_irqvector[26].handler=0x402823ec
up_timer_initialize: g_irqvector[27].handler=0x4029b2ac
up_timer_initialize: g_irqvector[28].handler=0x402823ec
up_timer_initialize: g_irqvector[29].handler=0x402823ec
up_timer_initialize: g_irqvector[30].handler=0x402823ec
up_timer_initialize: g_irqvector[31].handler=0x402823ec
up_timer_initialize: g_irqvector[32].handler=0x402823ec
up_timer_initialize: g_irqvector[33].handler=0x402823ec
up_timer_initialize: g_irqvector[34].handler=0x402823ec
up_timer_initialize: g_irqvector[35].handler=0x402823ec
up_timer_initialize: g_irqvector[36].handler=0x402823ec
up_timer_initialize: g_irqvector[37].handler=0x402823ec
up_timer_initialize: g_irqvector[38].handler=0x402823ec
up_timer_initialize: g_irqvector[39].handler=0x402823ec
up_timer_initialize: g_irqvector[40].handler=0x402823ec
up_timer_initialize: g_irqvector[41].handler=0x402823ec
up_timer_initialize: g_irqvector[42].handler=0x402823ec
up_timer_initialize: g_irqvector[43].handler=0x402823ec
up_timer_initialize: g_irqvector[44].handler=0x402823ec
up_timer_initialize: g_irqvector[45].handler=0x402823ec
up_timer_initialize: g_irqvector[46].handler=0x402823ec
up_timer_initialize: g_irqvector[47].handler=0x402823ec
up_timer_initialize: g_irqvector[48].handler=0x402823ec
up_timer_initialize: g_irqvector[49].handler=0x402823ec
up_timer_initialize: g_irqvector[50].handler=0x402823ec
up_timer_initialize: g_irqvector[51].handler=0x402823ec
up_timer_initialize: g_irqvector[52].handler=0x402823ec
up_timer_initialize: g_irqvector[53].handler=0x402823ec
up_timer_initialize: g_irqvector[54].handler=0x402823ec
up_timer_initialize: g_irqvector[55].handler=0x402823ec
up_timer_initialize: g_irqvector[56].handler=0x402823ec
up_timer_initialize: g_irqvector[57].handler=0x402823ec
up_timer_initialize: g_irqvector[58].handler=0x402823ec
up_timer_initialize: g_irqvector[59].handler=0x402823ec
up_timer_initialize: g_irqvector[60].handler=0x402823ec
up_timer_initialize: g_irqvector[61].handler=0x402823ec
up_timer_initialize: g_irqvector[62].handler=0x402823ec
up_timer_initialize: g_irqvector[63].handler=0x402823ec
up_timer_initialize: g_irqvector[64].handler=0x402823ec
up_timer_initialize: g_irqvector[65].handler=0x402823ec
up_timer_initialize: g_irqvector[66].handler=0x402823ec
up_timer_initialize: g_irqvector[67].handler=0x402823ec
up_timer_initialize: g_irqvector[68].handler=0x402823ec
up_timer_initialize: g_irqvector[69].handler=0x402823ec
up_timer_initialize: g_irqvector[70].handler=0x402823ec
up_timer_initialize: g_irqvector[71].handler=0x402823ec
up_timer_initialize: g_irqvector[72].handler=0x402823ec
up_timer_initialize: g_irqvector[73].handler=0x402823ec
up_timer_initialize: g_irqvector[74].handler=0x402823ec
up_timer_initialize: g_irqvector[75].handler=0x402823ec
up_timer_initialize: g_irqvector[76].handler=0x402823ec
up_timer_initialize: g_irqvector[77].handler=0x402823ec
up_timer_initialize: g_irqvector[78].handler=0x402823ec
up_timer_initialize: g_irqvector[79].handler=0x402823ec
up_timer_initialize: g_irqvector[80].handler=0x402823ec
up_timer_initialize: g_irqvector[81].handler=0x402823ec
up_timer_initialize: g_irqvector[82].handler=0x402823ec
up_timer_initialize: g_irqvector[83].handler=0x402823ec
up_timer_initialize: g_irqvector[84].handler=0x402823ec
up_timer_initialize: g_irqvector[85].handler=0x402823ec
up_timer_initialize: g_irqvector[86].handler=0x402823ec
up_timer_initialize: g_irqvector[87].handler=0x402823ec
up_timer_initialize: g_irqvector[88].handler=0x402823ec
up_timer_initialize: g_irqvector[89].handler=0x402823ec
up_timer_initialize: g_irqvector[90].handler=0x402823ec
up_timer_initialize: g_irqvector[91].handler=0x402823ec
up_timer_initialize: g_irqvector[92].handler=0x402823ec
up_timer_initialize: g_irqvector[93].handler=0x402823ec
up_timer_initialize: g_irqvector[94].handler=0x402823ec
up_timer_initialize: g_irqvector[95].handler=0x402823ec
up_timer_initialize: g_irqvector[96].handler=0x402823ec
up_timer_initialize: g_irqvector[97].handler=0x402823ec
up_timer_initialize: g_irqvector[98].handler=0x402823ec
up_timer_initialize: g_irqvector[99].handler=0x402823ec
up_timer_initialize: g_irqvector[100].handler=0x402823ec
up_timer_initialize: g_irqvector[101].handler=0x402823ec
up_timer_initialize: g_irqvector[102].handler=0x402823ec
up_timer_initialize: g_irqvector[103].handler=0x402823ec
up_timer_initialize: g_irqvector[104].handler=0x402823ec
up_timer_initialize: g_irqvector[105].handler=0x402823ec
up_timer_initialize: g_irqvector[106].handler=0x402823ec
up_timer_initialize: g_irqvector[107].handler=0x402823ec
up_timer_initialize: g_irqvector[108].handler=0x402823ec
up_timer_initialize: g_irqvector[109].handler=0x402823ec
up_timer_initialize: g_irqvector[110].handler=0x402823ec
up_timer_initialize: g_irqvector[111].handler=0x402823ec
up_timer_initialize: g_irqvector[112].handler=0x402823ec
up_timer_initialize: g_irqvector[113].handler=0x402823ec
up_timer_initialize: g_irqvector[114].handler=0x402823ec
up_timer_initialize: g_irqvector[115].handler=0x402823ec
up_timer_initialize: g_irqvector[116].handler=0x402823ec
up_timer_initialize: g_irqvector[117].handler=0x402823ec
up_timer_initialize: g_irqvector[118].handler=0x402823ec
up_timer_initialize: g_irqvector[119].handler=0x402823ec
up_timer_initialize: g_irqvector[120].handler=0x402823ec
up_timer_initialize: g_irqvector[121].handler=0x402823ec
up_timer_initialize: g_irqvector[122].handler=0x402823ec
up_timer_initialize: g_irqvector[123].handler=0x402823ec
up_timer_initialize: g_irqvector[124].handler=0x402823ec
up_timer_initialize: g_irqvector[125].handler=0x402823ec
up_timer_initialize: g_irqvector[126].handler=0x402823ec
up_timer_initialize: g_irqvector[127].handler=0x402823ec
up_timer_initialize: g_irqvector[128].handler=0x402823ec
up_timer_initialize: g_irqvector[129].handler=0x402823ec
up_timer_initialize: g_irqvector[130].handler=0x402823ec
up_timer_initialize: g_irqvector[131].handler=0x402823ec
up_timer_initialize: g_irqvector[132].handler=0x402823ec
up_timer_initialize: g_irqvector[133].handler=0x402823ec
up_timer_initialize: g_irqvector[134].handler=0x402823ec
up_timer_initialize: g_irqvector[135].handler=0x402823ec
up_timer_initialize: g_irqvector[136].handler=0x402823ec
up_timer_initialize: g_irqvector[137].handler=0x402823ec
up_timer_initialize: g_irqvector[138].handler=0x402823ec
up_timer_initialize: g_irqvector[139].handler=0x402823ec
up_timer_initialize: g_irqvector[140].handler=0x402823ec
up_timer_initialize: g_irqvector[141].handler=0x402823ec
up_timer_initialize: g_irqvector[142].handler=0x402823ec
up_timer_initialize: g_irqvector[143].handler=0x402823ec
up_timer_initialize: g_irqvector[144].handler=0x402823ec
up_timer_initialize: g_irqvector[145].handler=0x402823ec
up_timer_initialize: g_irqvector[146].handler=0x402823ec
up_timer_initialize: g_irqvector[147].handler=0x402823ec
up_timer_initialize: g_irqvector[148].handler=0x402823ec
up_timer_initialize: g_irqvector[149].handler=0x402823ec
up_timer_initialize: g_irqvector[150].handler=0x402823ec
up_timer_initialize: g_irqvector[151].handler=0x402823ec
up_timer_initialize: g_irqvector[152].handler=0x402823ec
up_timer_initialize: g_irqvector[153].handler=0x402823ec
up_timer_initialize: g_irqvector[154].handler=0x402823ec
up_timer_initialize: g_irqvector[155].handler=0x402823ec
up_timer_initialize: g_irqvector[156].handler=0x402823ec
up_timer_initialize: g_irqvector[157].handler=0x402823ec
up_timer_initialize: g_irqvector[158].handler=0x402823ec
up_timer_initialize: g_irqvector[159].handler=0x402823ec
up_timer_initialize: g_irqvector[160].handler=0x402823ec
up_timer_initialize: g_irqvector[161].handler=0x402823ec
up_timer_initialize: g_irqvector[162].handler=0x402823ec
up_timer_initialize: g_irqvector[163].handler=0x402823ec
up_timer_initialize: g_irqvector[164].handler=0x402823ec
up_timer_initialize: g_irqvector[165].handler=0x402823ec
up_timer_initialize: g_irqvector[166].handler=0x402823ec
up_timer_initialize: g_irqvector[167].handler=0x402823ec
up_timer_initialize: g_irqvector[168].handler=0x402823ec
up_timer_initialize: g_irqvector[169].handler=0x402823ec
up_timer_initialize: g_irqvector[170].handler=0x402823ec
up_timer_initialize: g_irqvector[171].handler=0x402823ec
up_timer_initialize: g_irqvector[172].handler=0x402823ec
up_timer_initialize: g_irqvector[173].handler=0x402823ec
up_timer_initialize: g_irqvector[174].handler=0x402823ec
up_timer_initialize: g_irqvector[175].handler=0x402823ec
up_timer_initialize: g_irqvector[176].handler=0x402823ec
up_timer_initialize: g_irqvector[177].handler=0x402823ec
up_timer_initialize: g_irqvector[178].handler=0x402823ec
up_timer_initialize: g_irqvector[179].handler=0x402823ec
up_timer_initialize: g_irqvector[180].handler=0x402823ec
up_timer_initialize: g_irqvector[181].handler=0x402823ec
up_timer_initialize: g_irqvector[182].handler=0x402823ec
up_timer_initialize: g_irqvector[183].handler=0x402823ec
up_timer_initialize: g_irqvector[184].handler=0x402823ec
up_timer_initialize: g_irqvector[185].handler=0x402823ec
up_timer_initialize: g_irqvector[186].handler=0x402823ec
up_timer_initialize: g_irqvector[187].handler=0x402823ec
up_timer_initialize: g_irqvector[188].handler=0x402823ec
up_timer_initialize: g_irqvector[189].handler=0x402823ec
up_timer_initialize: g_irqvector[190].handler=0x402823ec
up_timer_initialize: g_irqvector[191].handler=0x402823ec
up_timer_initialize: g_irqvector[192].handler=0x402823ec
up_timer_initialize: g_irqvector[193].handler=0x402823ec
up_timer_initialize: g_irqvector[194].handler=0x402823ec
up_timer_initialize: g_irqvector[195].handler=0x402823ec
up_timer_initialize: g_irqvector[196].handler=0x402823ec
up_timer_initialize: g_irqvector[197].handler=0x402823ec
up_timer_initialize: g_irqvector[198].handler=0x402823ec
up_timer_initialize: g_irqvector[199].handler=0x402823ec
up_timer_initialize: g_irqvector[200].handler=0x402823ec
up_timer_initialize: g_irqvector[201].handler=0x402823ec
up_timer_initialize: g_irqvector[202].handler=0x402823ec
up_timer_initialize: g_irqvector[203].handler=0x402823ec
up_timer_initialize: g_irqvector[204].handler=0x402823ec
up_timer_initialize: g_irqvector[205].handler=0x402823ec
up_timer_initialize: g_irqvector[206].handler=0x402823ec
up_timer_initialize: g_irqvector[207].handler=0x402823ec
up_timer_initialize: g_irqvector[208].handler=0x402823ec
up_timer_initialize: g_irqvector[209].handler=0x402823ec
up_timer_initialize: g_irqvector[210].handler=0x402823ec
up_timer_initialize: g_irqvector[211].handler=0x402823ec
up_timer_initialize: g_irqvector[212].handler=0x402823ec
up_timer_initialize: g_irqvector[213].handler=0x402823ec
up_timer_initialize: g_irqvector[214].handler=0x402823ec
up_timer_initialize: g_irqvector[215].handler=0x402823ec
up_timer_initialize: g_irqvector[216].handler=0x402823ec
up_timer_initialize: g_irqvector[217].handler=0x402823ec
up_timer_initialize: g_irqvector[218].handler=0x402823ec
up_timer_initialize: g_irqvector[219].handler=0x402823ec
AKLMNOPBIJQRQRuart_register: Registering /dev/console
QRuart_register: Registering /dev/ttyS0
QRAKLMNOPBIJQRQRQRwork_start_highpri: Starting high-priority kernel worker thread(s)
QRQRQRnx_start_application: StartinQRg init thread
QRQRQRlib_cxx_initialize: _sinit: 0x402a7000 _einit: 0x402a700QR0 _stext: 0x40280000 _etext: 0x402a8000
QRQRQRQRQRQRQRQnsh: sysinit: fopen failed: 2
QRQRQRQRQRQRQRQRQRQRQRQRQnsh: mkfatfs: command not found
QRQRQRQRQ
QNuttShell (NSH) NuttX-10.3.0-RC2
Qnsh> QQRnx_start: CPU0: Beginning Idle Loop
QRQRQRQRRRRRRR
```

## Boot Files for Manjaro Phosh on PinePhone

```text
[manjaro@manjaro-arm ~]$ ls -l /boot
total 38568
-rw-r--r-- 1 root root     1476 Jun 22 08:36 boot.scr
-rw-r--r-- 1 root root     1404 Apr  6 11:51 boot.txt
drwxr-xr-x 3 root root     4096 Oct 16  2021 dtbs
-rw-r--r-- 1 root root 20160520 Jul  3 14:56 Image
-rw-r--r-- 1 root root  8359044 Jul  3 14:56 Image.gz
-rw-r--r-- 1 root root  7327835 Jul 24 14:33 initramfs-linux.img
-rw-r--r-- 1 root root   722223 Apr  6 11:51 u-boot-sunxi-with-spl-pinephone-492.bin
-rw-r--r-- 1 root root   722223 Apr  6 11:51 u-boot-sunxi-with-spl-pinephone-528.bin
-rw-r--r-- 1 root root   722223 Apr  6 11:51 u-boot-sunxi-with-spl-pinephone-552.bin
-rw-r--r-- 1 root root   722223 Apr  6 11:51 u-boot-sunxi-with-spl-pinephone-592.bin
-rw-r--r-- 1 root root   722223 Apr  6 11:51 u-boot-sunxi-with-spl-pinephone-624.bin

[manjaro@manjaro-arm ~]$ ls -l /boot/dtbs
total 8
drwxr-xr-x 2 root root 8192 Jul 24 14:30 allwinner

[manjaro@manjaro-arm ~]$ ls -l /boot/dtbs/allwinner
total 1504
-rw-r--r-- 1 root root 13440 Jul  3 14:56 sun50i-a100-allwinner-perf1.dtb
-rw-r--r-- 1 root root 41295 Jul  3 14:56 sun50i-a64-amarula-relic.dtb
-rw-r--r-- 1 root root 41648 Jul  3 14:56 sun50i-a64-bananapi-m64.dtb
-rw-r--r-- 1 root root 40512 Jul  3 14:56 sun50i-a64-nanopi-a64.dtb
-rw-r--r-- 1 root root 39951 Jul  3 14:56 sun50i-a64-oceanic-5205-5inmfd.dtb
-rw-r--r-- 1 root root 41268 Jul  3 14:56 sun50i-a64-olinuxino.dtb
-rw-r--r-- 1 root root 41397 Jul  3 14:56 sun50i-a64-olinuxino-emmc.dtb
-rw-r--r-- 1 root root 42295 Jul  3 14:56 sun50i-a64-orangepi-win.dtb
-rw-r--r-- 1 root root 40316 Jul  3 14:56 sun50i-a64-pine64.dtb
-rw-r--r-- 1 root root 40948 Jul  3 14:56 sun50i-a64-pine64-lts.dtb
-rw-r--r-- 1 root root 40438 Jul  3 14:56 sun50i-a64-pine64-plus.dtb
-rw-r--r-- 1 root root 42979 Jul  3 14:56 sun50i-a64-pinebook.dtb
-rw-r--r-- 1 root root 53726 Jul  3 14:56 sun50i-a64-pinephone-1.0.dtb
-rw-r--r-- 1 root root 53753 Jul  3 14:56 sun50i-a64-pinephone-1.1.dtb
-rw-r--r-- 1 root root 53718 Jul  3 14:56 sun50i-a64-pinephone-1.2.dtb
-rw-r--r-- 1 root root 44110 Jul  3 14:56 sun50i-a64-pinetab.dtb
-rw-r--r-- 1 root root 44150 Jul  3 14:56 sun50i-a64-pinetab-early-adopter.dtb
-rw-r--r-- 1 root root 40816 Jul  3 14:56 sun50i-a64-sopine-baseboard.dtb
-rw-r--r-- 1 root root 42234 Jul  3 14:56 sun50i-a64-teres-i.dtb
-rw-r--r-- 1 root root 31407 Jul  3 14:56 sun50i-h5-bananapi-m2-plus.dtb
-rw-r--r-- 1 root root 32846 Jul  3 14:56 sun50i-h5-bananapi-m2-plus-v1.2.dtb
-rw-r--r-- 1 root root 31056 Jul  3 14:56 sun50i-h5-emlid-neutis-n5-devboard.dtb
-rw-r--r-- 1 root root 31277 Jul  3 14:56 sun50i-h5-libretech-all-h3-cc.dtb
-rw-r--r-- 1 root root 29939 Jul  3 14:56 sun50i-h5-libretech-all-h3-it.dtb
-rw-r--r-- 1 root root 31872 Jul  3 14:56 sun50i-h5-libretech-all-h5-cc.dtb
-rw-r--r-- 1 root root 29013 Jul  3 14:56 sun50i-h5-nanopi-neo2.dtb
-rw-r--r-- 1 root root 29704 Jul  3 14:56 sun50i-h5-nanopi-neo-plus2.dtb
-rw-r--r-- 1 root root 31401 Jul  3 14:56 sun50i-h5-nanopi-r1s-h5.dtb
-rw-r--r-- 1 root root 31082 Jul  3 14:56 sun50i-h5-orangepi-pc2.dtb
-rw-r--r-- 1 root root 29806 Jul  3 14:56 sun50i-h5-orangepi-prime.dtb
-rw-r--r-- 1 root root 29044 Jul  3 14:56 sun50i-h5-orangepi-zero-plus2.dtb
-rw-r--r-- 1 root root 29131 Jul  3 14:56 sun50i-h5-orangepi-zero-plus.dtb
-rw-r--r-- 1 root root 31911 Jul  3 14:56 sun50i-h6-beelink-gs1.dtb
-rw-r--r-- 1 root root 33042 Jul  3 14:56 sun50i-h6-orangepi-3.dtb
-rw-r--r-- 1 root root 30504 Jul  3 14:56 sun50i-h6-orangepi-lite2.dtb
-rw-r--r-- 1 root root 30287 Jul  3 14:56 sun50i-h6-orangepi-one-plus.dtb
-rw-r--r-- 1 root root 32368 Jul  3 14:56 sun50i-h6-pine-h64.dtb
-rw-r--r-- 1 root root 32882 Jul  3 14:56 sun50i-h6-pine-h64-model-b.dtb
-rw-r--r-- 1 root root 29544 Jul  3 14:56 sun50i-h6-tanix-tx6.dtb
-rw-r--r-- 1 root root 29305 Jul  3 14:56 sun50i-h6-tanix-tx6-mini.dtb

[manjaro@manjaro-arm ~]$ cat /boot/boot.txt
#
# /boot/boot.txt
# After modifying, run "pp-uboot-mkscr" to re-generate the U-Boot boot script.
#

#
# This is the description of the GPIO lines used in this boot script:
#
# GPIO #98 is PD2, or A64 ball W19, which controls the vibrator motor
# GPIO #114 is PD18, or A64 ball AB13, which controls the red part of the multicolor LED
# GPIO #115 is PD19, or A64 ball AB12, which controls the green part of the multicolor LED
# GPIO #116 is PD20, or A64 ball AB11, which controls the blue part of the multicolor LED
#

gpio set 98
gpio set 114

# Set root partition to the second partition of boot device
part uuid ${devtype} ${devnum}:1 uuid_boot
part uuid ${devtype} ${devnum}:2 uuid_root

setenv bootargs loglevel=4 console=tty0 console=${console} earlycon=uart,mmio32,0x01c28000 consoleblank=0 boot=PARTUUID=${uuid_boot} root=PARTUUID=${uuid_root} rw rootwait quiet audit=0 bootsplash.bootfile=bootsplash-themes/manjaro/bootsplash

if load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} /Image; then
  gpio clear 98
  if load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} /dtbs/${fdtfile}; then
    if load ${devtype} ${devnum}:${distro_bootpart} ${ramdisk_addr_r} /initramfs-linux.img; then
      gpio set 115
      booti ${kernel_addr_r} ${ramdisk_addr_r}:${filesize} ${fdt_addr_r};
    else
      gpio set 116
      booti ${kernel_addr_r} - ${fdt_addr_r};
    fi;
  fi;
fi

# EOF
```

## GIC Register Dump

Below is the dump of PinePhone's registers for [Arm Generic Interrupt Controller version 2](https://developer.arm.com/documentation/ihi0048/latest/)...

```text
HELLO NUTTX ON PINEPHONE!
- Ready to Boot CPU
- Boot from EL2
- Boot from EL1
- Boot to C runtime for OS Initialize
nx_start: Entry
up_allocate_heap: heap_start=0x0x400c4000, heap_size=0x7f3c000
arm64_gic_initialize: TODO: Init GIC for PinePhone
arm64_gic_initialize: GIC Version is 2
Earm_gic_dump: GIC: Entry arm_gic0_initialize NLINES=224
arm_gic_dump_cpu:   CPU Interface Registers:
arm_gic_dump_cpu:        ICR: 00000060    PMR: 000000f0    BPR: 00000003    IAR: 000003ff
arm_gic_dump_cpu:        RPR: 000000ff   HPIR: 000003ff   ABPR: 00000000
arm_gic_dump_cpu:       AIAR: 00000000  AHPIR: 00000000    IDR: 0202143b
arm_gic_dump_cpu:       APR1: 00000000   APR2: 00000000   APR3: 00000000   APR4: 00000000
arm_gic_dump_cpu:     NSAPR1: 00000000 NSAPR2: 00000000 NSAPR3: 00000000 NSAPR4: 00000000
arm_gic_dump_distributor:   Distributor Registers:
arm_gic_dump_distributor:        DCR: 00000000   ICTR: 0000fc66   IIDR: 0200143b
arm_gic_dump32:        ISR[01c81080]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISER/ICER[01c81100]
arm_gic_dumpregs:          0000ffff 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISPR/ICPR[01c81200]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        SAR/CAR[01c81300]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump4:        IPR[01c81400]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump4:        IPTR[01c81800]
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          00000000 00000000 01010100 01010101
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump16:        ICFR[01c81c00]
arm_gic_dumpregs:          aaaaaaaa 55540000 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 00000000 00000000
arm_gic_dump32:        PPSIR/SPISR[01c81d00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        NSACR[01c81e00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump8:        SCPR/SSPR[01c81f10]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump_distributor:        PIDR[01c81fd0]:
arm_gic_dump_distributor:          00000004 00000000 00000000 00000000
arm_gic_dump_distributor:          00000090 000000b4 0000002b
arm_gic_dump_distributor:        CIDR[01c81ff0]:
arm_gic_dump_distributor:          0000000d 000000f0 00000005 000000b1
arm_gic_dump: GIC: Exit arm_gic0_initialize NLINES=224
arm_gic_dump_cpu:   CPU Interface Registers:
arm_gic_dump_cpu:        ICR: 00000060    PMR: 000000f0    BPR: 00000003    IAR: 000003ff
arm_gic_dump_cpu:        RPR: 000000ff   HPIR: 000003ff   ABPR: 00000000
arm_gic_dump_cpu:       AIAR: 00000000  AHPIR: 00000000    IDR: 0202143b
arm_gic_dump_cpu:       APR1: 00000000   APR2: 00000000   APR3: 00000000   APR4: 00000000
arm_gic_dump_cpu:     NSAPR1: 00000000 NSAPR2: 00000000 NSAPR3: 00000000 NSAPR4: 00000000
arm_gic_dump_distributor:   Distributor Registers:
arm_gic_dump_distributor:        DCR: 00000000   ICTR: 0000fc66   IIDR: 0200143b
arm_gic_dump32:        ISR[01c81080]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISER/ICER[01c81100]
arm_gic_dumpregs:          0000ffff 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISPR/ICPR[01c81200]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        SAR/CAR[01c81300]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump4:        IPR[01c81400]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dump4:        IPTR[01c81800]
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          00000000 00000000 01010100 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dump16:        ICFR[01c81c00]
arm_gic_dumpregs:          aaaaaaaa 55540000 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 00000000 00000000
arm_gic_dump32:        PPSIR/SPISR[01c81d00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        NSACR[01c81e00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump8:        SCPR/SSPR[01c81f10]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump_distributor:        PIDR[01c81fd0]:
arm_gic_dump_distributor:          00000004 00000000 00000000 00000000
arm_gic_dump_distributor:          00000090 000000b4 0000002b
arm_gic_dump_distributor:        CIDR[01c81ff0]:
arm_gic_dump_distributor:          0000000d 000000f0 00000005 000000b1
FGarm_gic_dump: GIC: Entry arm_gic_initialize NLINES=224
arm_gic_dump_cpu:   CPU Interface Registers:
arm_gic_dump_cpu:        ICR: 00000060    PMR: 000000f0    BPR: 00000003    IAR: 000003ff
arm_gic_dump_cpu:        RPR: 000000ff   HPIR: 000003ff   ABPR: 00000000
arm_gic_dump_cpu:       AIAR: 00000000  AHPIR: 00000000    IDR: 0202143b
arm_gic_dump_cpu:       APR1: 00000000   APR2: 00000000   APR3: 00000000   APR4: 00000000
arm_gic_dump_cpu:     NSAPR1: 00000000 NSAPR2: 00000000 NSAPR3: 00000000 NSAPR4: 00000000
arm_gic_dump_distributor:   Distributor Registers:
arm_gic_dump_distributor:        DCR: 00000000   ICTR: 0000fc66   IIDR: 0200143b
arm_gic_dump32:        ISR[01c81080]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISER/ICER[01c81100]
arm_gic_dumpregs:          0000ffff 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISPR/ICPR[01c81200]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        SAR/CAR[01c81300]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump4:        IPR[01c81400]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dump4:        IPTR[01c81800]
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          00000000 00000000 01010100 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dump16:        ICFR[01c81c00]
arm_gic_dumpregs:          aaaaaaaa 55540000 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 00000000 00000000
arm_gic_dump32:        PPSIR/SPISR[01c81d00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        NSACR[01c81e00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump8:        SCPR/SSPR[01c81f10]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump_distributor:        PIDR[01c81fd0]:
arm_gic_dump_distributor:          00000004 00000000 00000000 00000000
arm_gic_dump_distributor:          00000090 000000b4 0000002b
arm_gic_dump_distributor:        CIDR[01c81ff0]:
arm_gic_dump_distributor:          0000000d 000000f0 00000005 000000b1
arm_gic_dump: GIC: Exit arm_gic_initialize NLINES=224
arm_gic_dump_cpu:   CPU Interface Registers:
arm_gic_dump_cpu:        ICR: 00000061    PMR: 000000f0    BPR: 00000007    IAR: 000003ff
arm_gic_dump_cpu:        RPR: 000000ff   HPIR: 000003ff   ABPR: 00000000
arm_gic_dump_cpu:       AIAR: 00000000  AHPIR: 00000000    IDR: 0202143b
arm_gic_dump_cpu:       APR1: 00000000   APR2: 00000000   APR3: 00000000   APR4: 00000000
arm_gic_dump_cpu:     NSAPR1: 00000000 NSAPR2: 00000000 NSAPR3: 00000000 NSAPR4: 00000000
arm_gic_dump_distributor:   Distributor Registers:
arm_gic_dump_distributor:        DCR: 00000001   ICTR: 0000fc66   IIDR: 0200143b
arm_gic_dump32:        ISR[01c81080]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISER/ICER[01c81100]
arm_gic_dumpregs:          0000ffff 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        ISPR/ICPR[01c81200]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        SAR/CAR[01c81300]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump4:        IPR[01c81400]
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          00000000 00000000 80000000 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dumpregs:          80808080 80808080 80808080 80808080
arm_gic_dump4:        IPTR[01c81800]
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          00000000 00000000 01010100 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dumpregs:          01010101 01010101 01010101 01010101
arm_gic_dump16:        ICFR[01c81c00]
arm_gic_dumpregs:          aaaaaaaa 55540000 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 55555555 55555555
arm_gic_dumpregs:          55555555 55555555 00000000 00000000
arm_gic_dump32:        PPSIR/SPISR[01c81d00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump32:        NSACR[01c81e00]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump8:        SCPR/SSPR[01c81f10]
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dumpregs:          00000000 00000000 00000000 00000000
arm_gic_dump_distributor:        PIDR[01c81fd0]:
arm_gic_dump_distributor:          00000004 00000000 00000000 00000000
arm_gic_dump_distributor:          00000090 000000b4 0000002b
arm_gic_dump_distributor:        CIDR[01c81ff0]:
arm_gic_dump_distributor:          0000000d 000000f0 00000005 000000b1
Hup_timer_initialize: up_timer_initialize: cp15 timer(s) running at 24.00MHz, cycle 24000
AMarm_gic_dump: GIC: Exit up_prioritize_irq IRQ=27
arm_gic_dump_cpu:   CPU Interface Registers:
arm_gic_dump_cpu:        ICR: 00000061    PMR: 000000f0    BPR: 00000007    IAR: 000003ff
arm_gic_dump_cpu:        RPR: 000000ff   HPIR: 000003ff   ABPR: 00000000
arm_gic_dump_cpu:       AIAR: 00000000  AHPIR: 00000000    IDR: 0202143b
arm_gic_dump_cpu:       APR1: 00000000   APR2: 00000000   APR3: 00000000   APR4: 00000000
arm_gic_dump_cpu:     NSAPR1: 00000000 NSAPR2: 00000000 NSAPR3: 00000000 NSAPR4: 00000000
arm_gic_dump_distributor:   Distributor Registers:
arm_gic_dump_distributor:        DCR: 00000001   ICTR: 0000fc66   IIDR: 0200143b
arm_gic_dump_distributor:        ISR: 00000000   ISER: 0000ffff   ISPR: 00000000    SAR: 00000000
arm_gic_dump_distributor:        IPR: a0000000   IPTR: 01010100   ICFR: 55540000  SPISR: 00000000
arm_gic_dump_distributor:      NSACR: 00000000   SCPR: 00000000
arm_gic_dump_distributor:        PIDR[01c81fd0]:
arm_gic_dump_distributor:          00000004 00000000 00000000 00000000
arm_gic_dump_distributor:          00000090 000000b4 0000002b
arm_gic_dump_distributor:        CIDR[01c81ff0]:
arm_gic_dump_distributor:          0000000d 000000f0 00000005 000000b1
NOPBIarm_gic_du
```

pinephone-nuttx

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