Android TI Guide

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

Introduction

This page describes how to build and deploy Android 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.

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: Do not use other Ubuntu releases other than the ones recommended above. Variscite provides Docker containers that can be used for a development environment as an alternative to using 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-get -y install gnupg flex bison gperf build-essential zip gcc-multilib g++-multilib 
$ sudo apt-get -y install libc6-dev-i386 libncurses5 libncurses5-dev x11proto-core-dev libx11-dev lib32z-dev libz-dev libssl-dev
$ sudo apt-get -y install ccache libgl1-mesa-dev libxml2-utils xsltproc unzip bc
$ sudo apt-get -y install uuid uuid-dev zlib1g-dev liblz-dev liblzo2-2 liblzo2-dev lzop git curl  
$ sudo apt-get -y install u-boot-tools mtd-utils android-tools-fsutils device-tree-compiler gdisk m4 dwarves libgnutls28-dev
$ sudo apt-get -y install libelf-dev cpio lz4 python-is-python3 

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The package android-tools-fsutils is obsolete and has been replaced by android-sdk-libsparse-utils.

$ sudo apt-get -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-get update
$ sudo apt-get 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 add-apt-repository ppa:deadsnakes/ppa
$ sudo apt-get update
$ sudo apt-get 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/
$ repo init -u git@github.com:varigit-dev/variscite-bsp-platform.git -b develop_ti_android13_RND-1731_android -m RLS_09_00_Bootloader.xml
$ repo sync -j4
$ mkdir -p ${YOUR_PATH}/ti-kernel-aosp/ && cd $_
$ repo init -u git@github.com:varigit-dev/variscite-bsp-platform.git -b develop_ti_android13_RND-1731_android -m RLS_09_00_Kernel.xml
$ repo sync -j4

Clone Variscite's AOSP sources

$ mkdir -p ${YOUR_PATH}/ti-aosp-13 && cd $_
$ repo init -u git@github.com:varigit-dev/variscite-bsp-platform.git -b develop_ti_android13_RND-1731_android -m RLS_09_00.xml

Build Android Images

Change to Android top level directory.

$ cd ~/var_aosp_ti-13_09_00_00/ti-aosp-13
$ source build/envsetup.sh

or

$ lunch am62x_var_som-user

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

$ export PATH=/usr/lib/jvm/java-8-openjdk-amd64/bin:$PATH

Build Android

Switching from eMMC build to SD card build and vice versa

• For eMMC boot

$ m TARGET_AVB_ENABLE=true -j4  2>&1 | tee build1-1.log 

• For SD boot

$ m TARGET_SDCARD_BOOT=true TARGET_AVB_ENABLE=true -j4 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. Directly from SD card
2. U-Boot boots from on-SOM eMMC

Flash and boot Android from SD card

Create a bootable SD card

Partition and format SD card, and copy all images

$ sudo ./flash-all -f <name> /dev/sdX;sync

• Replace <name> with the actual desired setup name according to the second table in the "Images created by the Android build" section.
• 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

Preparing images

The default super.img, format is suitable for flashing using fastboot, and must be modified for flashing using 'dd'.

$ cd out/target/product/am62x_var_som
$ simg2img super.img super_raw.img

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:

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

On the Host PC:

Replace <name> with the actual desired setup name according to the table in the "Images created by the Android build" section.

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
$ ./imx-make.sh bootloader kernel -j4
$ make otapackage -j4 2>&1

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 /cache folder)
• 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
 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 monit logcat for operation progress. After a successful update you can reboot into the updated version.

You can check chapter 7 of official TI "Android User Guide" for further "Over-The-Air (OTA) Update" examples.

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 ~/var_aosp_ti-13_09_00_00/ti-aosp-13
$ source build/envsetup.sh
$ lunch am62x_var_som-userdebug

$ ./imx-make.sh kernel -j4

Toolchain setup for manual build

Setup the toolchain path to point to arm-linux-androideabi- tools in prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin

$ export ARCH=arm64
$ export CROSS_COMPILE=~/var_aosp_ti-13_09_00_00/ti-aosp-13/prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/bin/aarch64-linux-android-

Unlock device for fastboot

Our build behaves like any other standard Android device.

To use fastboot, you should go through the following steps

• Settings => System => About Tablet => Build number
• keep on tapping until you see a prompt that says "You are now a developer!"
• Settings => System => Advanced => Developer options => OEM unlocking
• reboot to bootloader
• type "fastboot 0" in the U-Boot command line
• run "sudo `which fastboot` oem unlock" from the Host PC
• wait until the unlock process is complete
• proceed for flashing