Debian Customizing U-Boot AM62

Warning: This page is designed to be used with a 'release' URL parameter.

This page is using the default release am62-debian-bookworm-6.1.83_09.02.01.10-v1.0.
To view this page for a specific Variscite SoM and software release, please follow these steps:

1. Visit variwiki.com
2. Select your SoM
3. Select the software release

VAR-SOM-AM62 - Debian Customize from source code

Introduction

This guide demonstrates how to patch and rebuild the VAR-SOM-AM62 U-Boot images using Yocto.

To learn how to build the U-Boot images outside of Yocto, see: Build U-Boot from source code

Before Starting

Before starting this guide, you must have the Yocto environment set and be able to build images for the VAR-SOM-AM62.

Please see: Build Yocto from source code.

The remainder of the guide assumes the Yocto working directory is ~/var-ti-yocto

Making changes in the source code

Choose one of the following three methods to customize the U-Boot source code and build it using Yocto:

Add your patches on top of the Variscite source code

Fetch the U-Boot source:

$ MACHINE=am62x-var-som bitbake -c unpack virtual/bootloader
$ mkdir -p ../local_repos/ti-u-boot
$ cp -a arago-tmp-default-glibc/work/am62x_var_som-oe-linux/u-boot-variscite/<uboot version>/git/. ../local_repos/ti-u-boot
$ cd ../local_repos/ti-u-boot
$ git reset --hard
$ git clean -fdx

Next, make the desired changes to the U-Boot source code. After changing the source code, create a diff file:

$ cd ~/var-ti-yocto/local_repos/ti-u-boot
$ vim board/variscite/am62x_var_som/am62x_var_som.c
$ vim include/configs/am62x_var_som.h

edit and save

$ git diff > ~/var-ti-yocto/tisdk/sources/meta-variscite-bsp-ti/recipes-bsp/u-boot/u-boot-variscite/uboot.diff

Please refer How to Download Debian Source Code and to apply the above created U-Boot patch when building the Debian image.After cloned the debian source code , the code will be located under ~/debian_am62x_var_som/ti-bdebstrap/.

Create the directory ~/debian_am62x_var_som/ti-bdebstrap/patches/ti-u-boot and copy the uboot.diff patch.

$ cp ~/var-ti-yocto/tisdk/sources/meta-variscite-bsp-ti/recipes-bsp/u-boot/u-boot-variscite/uboot.diff  ~/debian_am62x_var_som/ti-bdebstrap/patches/ti-u-boot

Refer to Build and flash the debian image with uboot changes.

Use your remote repository on GitHub

Using this method Yocto will fetch the source code from your remote repository on GitHub.

Create a GitHub account and upload your proprietary U-Boot to a new repository: You can fork our repository to your account by visiting the following link and clicking on "Fork" at the top right of the screen: https://github.com/varigit/ti-u-boot/tree/ti-u-boot-2023.04_09.02.01.10_var01

Alternatively, you can clone the repository to your local machine, and push it later to your account.

Refer How to Download Debian Source Code'. After downloaded the source open the file ~/debian_am62x_var_som/ti-bdebstrap/configs/bsp_sources.toml and look for the tag '.

   atf_srcrev = "00f1ec6b8740ccd403e641131e294aabacf2a48b"
   optee_srcrev = "012cdca49db398693903e05c42a254a3a0c0d8f2"
   uboot_srcuri = "https://github.com/varigit/ti-u-boot.git"
   uboot_srcrev = "80ceb4d91326e00edd22a3fabf5dd2d64f6a7635"
   linux_fw_srcrev = "09.02.00.010"

Building U-Boot using Yocto

After making the desired changes to the source code following one of the methods described in the Making changes in the source code, you can build the U-Boot images by running:

$ cd ~/var-ti-yocto/tisdk/build
$ . conf/setenv

# Build only the U-Boot images:
$ MACHINE=am62x-var-som bitbake -c deploy u-boot-variscite                    # tispl.bin and u-boot.img
$ MACHINE=am62x-var-som bitbake -c deploy mc:k3r5:u-boot-variscite            # tiboot3.bin

# Optionally, you may skip building U-Boot and just build your image:
$ MACHINE=am62x-var-som bitbake <image name>

The relevant output files are:

deploy-ti/images/am62x-var-som/u-boot.img
deploy-ti/images/am62x-var-som/tispl.bin
deploy-ti/images/am62x-var-som/tiboot3.bin

see: Build U-Boot from source code to learn how to update a running board with these images.