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VAR-SOM-AM62 - Android 13-09.00.00 Developer Guide

Introduction

This page describes how to build and deploy Android 13 on the VAR-SOM-AM62. It is based on TI's Android 13-09.00.00 release.

Overview

The objective of this document is to guide VAR-SOM-AM62 Android developers to obtain Android 13 sources, setting up host environment, compilation, and deployment.

This document contains instructions for:

Hardware and software requirements.
Setup the hardware.
Setup the toolchain.
Download & build the sources.
Install the binaries on the VAR-SOM-AM62 SOM and variants.
Making Changes to kernel/configuration and update VAR-SOM-AM62 SOM and variants.

Supported Hardware and Features

Hardware Requirements

You will need the Variscite VAR-SOM-AM62 based evaluation kit.

Host (PC) Setup Requirements

The host development environment for Android is based on Ubuntu, please install one of the following Ubuntu versions:

Ubuntu 20.04/22.04 64bit LTS http://www.ubuntu.com/download/desktop

If you are running Linux in a virtual machine you need at least 16GB of RAM and 32 GB of swap.
The build process requires ~250GB of free storage space of SSD.
Before starting a build, make sure you have adequate free space available.

NOTE: Avoid using Ubuntu releases other than those recommended above.

Variscite offers Docker containers as an alternative for a development environment, which can be used instead of a virtual machine or a dedicated computer.
To learn more, please see Variscite's Docker Build Environment guide.
Windows with WSL/WSL2 is not supported for Android BSP.

Install required packages on host PC

$ sudo apt -y install gnupg flex bison gperf build-essential gcc-multilib g++-multilib
$ sudo apt -y install python3-pyelftools python3-dev python3.6 python2 python-is-python3
$ sudo apt -y install libc6-dev-i386 libncurses5 libncurses5-dev lib32z-dev libz-dev liblz-dev liblzo2-2 liblzo2-dev lzop lz4 cpio
$ sudo apt -y install libgl1-mesa-dev libxml2-utils xsltproc unzip bc libssl-dev ccache curl
$ sudo apt -y install git zip swig mtools uuid uuid-dev zlib1g-dev u-boot-tools lib32z1-dev fontconfig
$ sudo apt -y install mtd-utils device-tree-compiler gdisk m4 dwarves libgnutls28-dev libelf-dev x11proto-core-dev libx11-dev

For Ubuntu 20.04 and above:
The package android-tools-fsutils is obsolete and has been replaced by android-sdk-libsparse-utils.

$ sudo apt -y install android-sdk-libsparse-utils

Configure Git

$ git config --global user.name "Your Name"
$ git config --global user.email "Your Email"

Install the OpenJDK

To install it:

$ sudo apt update
$ sudo apt install openjdk-8-jdk

If your Ubuntu version is missing the package (which shouldn't happen), add the PPA repository and run the previous commands again:

$ sudo add-apt-repository ppa:openjdk-r/ppa

Update the default Java version by running:

$ sudo update-alternatives --config java
$ sudo update-alternatives --config javac

Note: The build process requires about 500GB of free space.

Check Python Version

In the next steps, we will download (from Google repositories) the command repo, used to download all the Android source repositories.

Certain tools like bpttools requires python2 which is not available default on Ubuntu 20.04 or 22.04 LTS.
Ubuntu 20.04/22.04 LTS users can install it running

$ sudo apt install software-properties-common
$ sudo add-apt-repository ppa:deadsnakes/ppa
$ sudo apt update
$ sudo apt install python3.6 python2

Make sure you use latest repo tool for all bug fixes

Obtain Source Code

Variscite's Linux kernel and U-Boot are available through Github. Required patches for the Android file system are pre-installed

Download Google Repo Tool

$ mkdir -p ~/bin
$ curl -o ~/bin/repo https://commondatastorage.googleapis.com/git-repo-downloads/repo
$ chmod a+x ~/bin/repo
$ export PATH=~/bin:$PATH

Clone Variscite's U-Boot and Linux kernel Sources

$ mkdir ~/var_aosp_ti-13_09_00_00 && cd $_
$ export YOUR_PATH=$PWD

$ mkdir -p ${YOUR_PATH}/ti-bootloader-aosp/ && cd $_
$ repo init -u https://github.com/varigit/variscite-bsp-platform.git -b ti-android-13.0.0_r62-var01 -m RLS_09_00_Bootloader.xml
$ repo sync -j$(nproc)

$ mkdir -p ${YOUR_PATH}/ti-kernel-aosp/ && cd $_
$ repo init -u https://github.com/varigit/variscite-bsp-platform.git -b ti-android-13.0.0_r62-var01 -m RLS_09_00_Kernel.xml
$ repo sync -j$(nproc)

Clone Variscite's AOSP Sources

$ mkdir -p ${YOUR_PATH}/ti-aosp-13 && cd $_
$ repo init -u https://github.com/varigit/variscite-bsp-platform.git -b ti-android-13.0.0_r62-var01 -m RLS_09_00.xml
$ repo sync -j$(nproc)

Apply Variscite's platforms patches and install toolchains

$ cd ${YOUR_PATH}/ti-aosp-13/device
$ variscite/scripts/install.sh

Build Bootloader Components

Export Toolchains and setup paths

$ export PATH=$PATH:${YOUR_PATH}/ti-bootloader-aosp/toolchain//bin:${YOUR_PATH}/ti-bootloader-aosp/toolchain//bin

$ export G_ATF_SRC_DIR="${YOUR_PATH}/ti-bootloader-aosp/arm-trusted-firmware"
$ export G_OPTEE_SRC_DIR="${YOUR_PATH}/ti-bootloader-aosp/optee_os"
$ export G_CORE_LINUX_FIRMWARE_SRC_DIR="${YOUR_PATH}/ti-bootloader-aosp/ti-linux-firmware"
$ export G_UBOOT_SRC_DIR="${YOUR_PATH}/ti-bootloader-aosp/ti-u-boot"

$ export G_UBOOT_DEF_CONFIG_R="am62x_var_som_r5_defconfig"
$ export G_UBOOT_DEF_CONFIG_A="am62x_var_som_a53_defconfig"

Building ARM Trusted Firmware (ATF)

$ cd ${G_ATF_SRC_DIR}
$ make distclean
$ make -j$(nproc) E=0 CROSS_COMPILE=aarch64-none-linux-gnu- ARCH=aarch64 PLAT=k3 TARGET_BOARD=lite SPD=opteed CFLAGS+="-DK3_PM_SYSTEM_SUSPEND=1"

Building OP-TEE OS

$ cd ${G_OPTEE_SRC_DIR}
$ make clean && rm -rf out
$ make -j$(nproc) PLATFORM=k3 CFG_ARM64_core=y CROSS_COMPILE=arm-none-linux-gnueabihf- CROSS_COMPILE64=aarch64-none-linux-gnu-

Building U-Boot for R5 Core

$ cd ${G_UBOOT_SRC_DIR}
$ make mrproper
$ make -C ${G_UBOOT_SRC_DIR} mrproper
$ make ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- ${G_UBOOT_DEF_CONFIG_R} O=${G_UBOOT_SRC_DIR}/out/r5
$ make -j$(nproc) ARCH=arm CROSS_COMPILE=arm-none-linux-gnueabihf- BINMAN_INDIRS=${G_CORE_LINUX_FIRMWARE_SRC_DIR} O=${G_UBOOT_SRC_DIR}/out/r5

Building U-Boot for A53 Core with Android

$ cd ${G_UBOOT_SRC_DIR}
$ make mrproper
$ make ARCH=arm CROSS_COMPILE=aarch64-none-linux-gnu- ${G_UBOOT_DEF_CONFIG_A} O=${G_UBOOT_SRC_DIR}/out/a53
$ make ARCH=arm CROSS_COMPILE=aarch64-none-linux-gnu- am62x_android_a53.config O=${G_UBOOT_SRC_DIR}/out/a53
$ make -j$(nproc) ARCH=arm CROSS_COMPILE=aarch64-none-linux-gnu- \
      BL31=${G_ATF_SRC_DIR}/build/k3/lite/release/bl31.bin \
      TEE=${G_OPTEE_SRC_DIR}/out/arm-plat-k3/core/tee-pager_v2.bin \
      BINMAN_INDIRS=${G_CORE_LINUX_FIRMWARE_SRC_DIR} O=${G_UBOOT_SRC_DIR}/out/a53

Copying Bootloader Images to AOSP Build

$ cp ${G_UBOOT_SRC_DIR}/out/r5/tiboot3-am62x-hs-fs-am62x-var-som.bin ${YOUR_PATH}/ti-aosp-13/vendor/ti/am62x/bootloader/am62x-sk/tiboot3-hsfs.bin
$ cp ${G_UBOOT_SRC_DIR}/out/r5/tiboot3-am62x-gp-am62x-var-som.bin ${YOUR_PATH}/ti-aosp-13/vendor/ti/am62x/bootloader/am62x-sk/tiboot3.bin
$ cp ${G_UBOOT_SRC_DIR}/out/a53/tispl.bin ${G_UBOOT_SRC_DIR}/out/a53/u-boot.img ${YOUR_PATH}/ti-aosp-13/vendor/ti/am62x/bootloader/am62x-sk/

Building the Kernel Image

$ cd ${YOUR_PATH}/ti-kernel-aosp/
$ export DIST_DIR=${YOUR_PATH}/ti-aosp-13/device/ti/am62x-kernel/kernel/6.1
$ tools/bazel run //common:ti_dist -- --dist_dir=$DIST_DIR

Note: The building process using the bazel tool is not a standard kernel build process, unlike make/soong. Google has published the guideline and package GKI bazel build, refer to https://source.android.com/docs/core/architecture/kernel/generic-kernel-image for more details.

To re-build Kernel fast for changes from the previous full build

$ tools/bazel run --config=fast //common:ti_dist -- --dist_dir=$DIST_DIR

Build Android Images

Change to Android top level directory.

$ cd ${YOUR_PATH}/ti-aosp-13
$ source build/envsetup.sh
$ lunch am62x_var_som-userdebug

or

$ lunch am62x_var_som-user

Note: userdebug build creates a debuggable version of Android.
user build creates a production version of Android.

Build Android File System

Switching from eMMC build to SD card build and vice versa

For eMMC boot

$ m -j$(nproc) 2>&1 | tee build-emmc.log

For SD boot (Booting the entire Android from SDCard only)

$ m TARGET_SDCARD_BOOT=true -j$(nproc) 2>&1 | tee build1-1.log

Images created by the Android build

The resulted images are located in out/target/product/am62x_var_som.

Boot options

Boot options of the Android:
1. U-Boot boots from on-SOM eMMC
2. Directly from SD card (Requires separate build for bootloader and AOSP images. See "Patch U-boot to be able to flash Android on sdcard via fastboot" above.)

Flash and boot Android from SD card

Create a bootable SD card

$ cd ${YOUR_PATH}/{{#var:BUILD_FOLDER_ANDROID}}
$ sudo ./device/variscite/scripts/sh/var-mksdcard.sh /dev/sdX; sync

Replace /dev/sdX with your true device, You can identify it with dmesg.

Boot From SD card

Power-off the board.
Insert the SD card into the SD card slot of the carrier board (DVK)
Make sure the Boot Mode is set to SD card: see Setting the Boot Mode section
Power up the board - it will boot into Linux from the SD card

Flash and boot Android from eMMC

Flashing Android from Linux shell (when the primary installation android)

An example of flashing eMMC, can be found here.

Follow the following steps instructions above:

1. Preparing a rescue SD card;

2. Flash from command line (use the install_android.sh script)

Further, follow the steps described in paragraph "Flashing Android with USB Fastboot"

Flashing Android with USB Fastboot

Install tools on host

$ sudo apt-get install android-tools-adb android-tools-fastboot

Note: Make sure you built Android for eMMC
Connect the target with host PC at fastboot mode:

Connect a USB OTG cable from the target board OTG port to a your host machine USB HOST port.
Power up the board and hit return/space to stop the boot at U-Boot.
type fastboot 0 in the U-Boot command line.

On the Host PC:

Update Android firmware

Generate OTA packages

For generating "OTA" packages, use the following commands:

$ cd ~/var_aosp_ti-13_09_00_00/ti-aosp-13
$ source build/envsetup.sh 
$ lunch PRODUCT=am62x_var_som-userdebug
$ m otapackage

Install OTA package to device:

Extract payload.bin and payload_properties.txt from OTA zip file

Push file payload.bin to somewhere on the device (typically /data/ota_package folder)

 adb push payload.bin /data/ota_package/payload.bin

Open payload_properties.txt on an editor to copy its content, lets suppose it's like in the TI manual:

 FILE_HASH=0fSBbXonyTjaAzMpwTBgM9AVtlBeyOigpCCgkoOfHKY=
 FILE_SIZE=379074366
 METADATA_HASH=Icrs3NqoglzyppyCZouWKbo5f08IPokhlUfHDmz77WQ/de8Dgp9zFXt8Fo+Hxccp465uTOvKNsteWU=
 METADATA_SIZE=46866

Input the following command on the board's console to update:

 su
 setenforce 0
 update_engine_client --payload=file:///data/ota_package/payload.bin --update --headers="FILE_HASH=0fSBbXonyTjaAzMpwTBgM9AVtlBeyOigpCCgkoOfHKY=
 FILE_SIZE=379074366
 METADATA_HASH=Icrs3NqoglzyppyCZouWKbo5f08IPokhlUfHDmz77WQ/de8Dgp9zFXt8Fo+Hxccp465uTOvKNsteWU=
 METADATA_SIZE=46866"

Android 13 Make sure that the -- header equals to the exact content of payload_properties.txt without "space" or "return" character.

After issuing the command, nothing seems to happen on the device, but you can monitor logcat for operation progress. After a successful update, you can reboot into the updated version (_b/_a) slot.

Manual operations

Build boot.img

When you perform changes to the kernel, you may build boot.img solely instead of building the whole Android.

$ cd ${YOUR_PATH}/ti-kernel-aosp/
$ export DIST_DIR=${YOUR_PATH}/ti-aosp-13/device/variscite/am62x-kernel/kernel/6.1
$ tools/bazel run --lto=full //common:ti_dist -- --dist_dir=$DIST_DIR
$ cd ${YOUR_PATH}/ti-aosp-13
$ lunch am62x_var_som-userdebug
$ m TARGET_AVB_ENABLE=true

Menu Config

$ cd ${YOUR_PATH}/ti-kernel-aosp/
$ tools/bazel run //common:ti_config -- menuconfig

Porting Drivers Notes

Actual Kernel source code is in ${YOUR_PATH}/ti-kernel-aosp/common
Defconfig Used in the kernel is from Google: ${YOUR_PATH}/ti-kernel-aosp/common/arch/arm64/configs/gki_defconfig
All drivers and SOC infrastructure is via modules and is setup by: ${YOUR_PATH}/ti-kernel-aosp/common/arch/arm64/configs/ti_gki.fragment
Your driver/ kernel module .ko must be added to GKI module list

 
    module_outs = COMMON_GKI_MODULES_LIST + [
     "net/wireless/your_module.ko",    
     "drivers/spi/your_driver.ko",
    ]

Your driver module dependencies must be resolved and must align ${YOUR_PATH}/ti-aosp-13/device/variscite/am62x_var_som/BoardConfig.mk

with following

BOARD_VENDOR_RAMDISK_KERNEL_MODULES += \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/zsmalloc.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/zram.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/ti-msgmgr.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/ti_sci.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/ti_sci_pm_domains.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/phy-omap-usb2.ko \
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/syscon-clk.ko \
                 |                                   |
                 |                                   |
        device/variscite/am62x-kernel/kernel/$(TARGET_KERNEL_USE)/your_driver.ko

Android TI Guide