CL-SOM-AM57x: U-Boot: Building Images

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The CompuLab CL-SOM-AM57x System-on-Module / Computer-on-Module firmware consists of two components: Secondary Program Loader (SPL) and U-Boot. Both components are based on U-Boot source code. SPL is the bootstrap utility invoked by the CPU internal boot ROM code of the AM57x SoC. SPL performs minimal hardware initialization and loads U-Boot from the same boot device. U-Boot initializes hardware modules necessary for system boot and loads the operating system.
The latest U-Boot package is available at the CL-SOM-AM57x Resources web page.

Building Firmware images for CL-SOM-AM57x

Getting U-Boot sources

There are two ways to get U-Boot sources that can be used as a baseline for CL-SOM-AM57x SPL and U-Boot. You can create a copy of "Das U-Boot" source tree or download a snapshot and extract it. We assume that you have created /home/development/cl-som-am57x/u-boot directory for CL-SOM-AM57x u-boot development.

Snapshot download

  • Download v2017.01 snapshot with your web browser.
  • Extract the downloaded archive u-boot-a705ebc.tar.gz
cd /home/development/cl-som-am57x/u-boot
tar xvf /path/to/downloaded/u-boot-a705ebc.tar.gz
mv u-boot u-boot-cl-som-am57x
This will create /home/development/cl-som-am57x/u-boot/u-boot-cl-som-am57x directory containing U-Boot source code tree.
  • Apply the CL-SOM-AM57x patch
cd /home/development/cl-som-am57x/u-boot/u-boot-cl-som-am57x
patch -p1 < /path/to/cl-som-am57x-u-boot/u-boot/u-boot-v2017.01-cl-som-am57x-1.3.patch

Git clone

  • Install git version control system.
  • Create a clone of U-Boot tree
cd /home/development/cl-som-am57x/u-boot
git clone git:// u-boot-cl-som-am57x
  • Create a branch for CL-SOM-AM57x development. The CL-SOM-AM57x patches are generated vs. v2017.01 tag (a705ebc81b7f91bbd0ef7c634284208342901149 commit) in the U-Boot tree. It is recommended to use exactly the same baseline to avoid merge conflicts.
cd u-boot-cl-som-am57x
git checkout -b cl-som-am57x-dev v2017.01
  • Apply the CL-SOM-AM57x patch
git am ~/device/cl-som-am57x/package/cl-som-am57x-u-boot/u-boot/patches/*

Building the firmware images

In this section we assume that any version of a toolchain is installed on a host machine and it's location is added to the PATH.

export ARCH=arm
export CROSS_COMPILE=arm-none-linux-eabi-
make mrproper
make cl-som-am57x_defconfig && make

In the example above, CL-SOM-AM57x firmware images for SPL (MLO) and U-Boot (u-boot.img) will be created in /home/development/cl-som-am57x/u-boot/u-boot-cl-som-am57x.

See also