Yocto Kirkstone OpenSTLinux for VisionSOM-STM32MP1

Yocto Kirkstone OpenSTLinux for VisionSOM-STM32MP1

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Introduction

This tutorial explains how to build a Yocto-based OpenSTLinux system for VisionSOM-STM32MP1 modules with VisionCB-STM32MP1-STD carrier board and meta-somlabs support layer. Distribution for SoMLabs modules use the following components:

• kernel (5.15.67): https://github.com/SoMLabs/somlabs-linux-stm32mp1/tree/v5.15-stm32mp-somlabs
• u-boot (2021.10): https://github.com/SoMLabs/somlabs-uboot-stm32mp1/tree/v2021.10-stm32mp-somlabs
• meta-somlabs (kirkstone): https://github.com/SoMLabs/openst-meta-somlabs/tree/kirkstone

meta-somlabs

Meta-somlabs layer should be used in order to build the st-image-weston image. It provides changes including the QT libraries and the SoMLabs demo application.

Building the system image

In order to build the system image a Distribution Package provided by STMicroelectronics is required. The whole building process is described on the ST wiki pages:

https://wiki.st.com/stm32mpu/wiki/STM32MP1_Distribution_Package

Yocto is using absolute directory path to give names to intermediate files. If the path is too long, Yocto build fails because file names exceed the maximum size supported by the file system. In that case, installation directory path should be renamed to reduce the overall absolute path name.

The summary of required steps is shown below:

mkdir st-yocto
cd st-yocto
repo init -u https://github.com/STMicroelectronics/oe-manifest.git -b refs/tags/openstlinux-5.15-yocto-kirkstone-mp1-v22.11.23
repo sync
cd layers/meta-st
git clone -b kirkstone https://github.com/SoMLabs/openst-meta-somlabs.git meta-somlabs
cd ../../
DISTRO=openstlinux-weston MACHINE=<MACHINE_NAME> source layers/meta-st/scripts/envsetup.sh
bitbake st-image-weston

The following VisionSOM machines are available:

• mp157a-dsi-ph-emmc-mx VisionSOM-STM32MP1 eMMC module with VisionCB-STM32MP1-STD board and ph720128t003 DSI display
• mp157a-dsi-ph-sd-mx VisionSOM-STM32MP1 SD-card module with VisionCB-STM32MP1-STD board and ph720128t003 DSI display
• mp157a-dsi-rvt-emmc-mx VisionSOM-STM32MP1 eMMC module with VisionCB-STM32MP1-STD board and rvt70hsmnwc00 DSI display
• mp157a-hdmi-lt-emmc-mx VisionSOM-STM32MP1 eMMC module with VisionCB-STM32MP1-STD board and lt8912b HDMI bridge
• mp157a-hdmi-lt-sd-mx VisionSOM-STM32MP1 SD-card module with VisionCB-STM32MP1-STD board and lt8912b HDMI bridge
• mp157a-rgb-ph-emmc-mx VisionSOM-STM32MP1 eMMC module with VisionCB-STM32MP1-STD board and ph800480t013 RGB display
• mp157a-rgb-ph-sd-mx VisionSOM-STM32MP1 SD-card module with VisionCB-STM32MP1-STD board and ph800480t013 RGB display

The compiled image files are located in the directory:

st-yocto/build-openstlinuxweston-<MACHINE_NAME>/tmp-glibc/deploy/images/<MACHINE_NAME>

Installing SD card image

The SD card image needs to be created using the available script after the building process:

cd tmp-glibc/deploy/images/<MACHINE_NAME>/scripts
./create_sdcard_from_flashlayout.sh ../flashlayout_st-image-weston/trusted/FlashLayout_sdcard_<MACHINE_NAME>-trusted.tsv

The system image is located in the FlashLayout_sdcard_<MACHINE_NAME>-trusted.raw file in the tmp-glibc/deploy/images/<MACHINE_NAME> directory. To install the image to a card connected to host PC the dd command may be used:

sudo dd if=FlashLayout_sdcard_<MACHINE_NAME>-trusted.raw of=/dev/sdX bs=1M

To boot the system from SD card on VisionCB-STM32MP1-STD board the BOOT jumpers must be set to 101.

Installing eMMC image

To install the built system on eMMC memory the STM32CubeProgrammer has to be used. It is available to download from the STMicroelectronics website: https://www.st.com/en/development-tools/stm32cubeprog.html

In order to program the module on VisionCB-STM32MP1-STD board, the BOOT jumpers need to be set to 000 to enable DFU boot. STM32CubeProgrammer should be connected by the USB cable connected to the USB-OTG socket. After programming the BOOT jumpers need to be set to 010 in order to run the installed system.

The details about using the STM32CubeProgrammer may be found on the ST wiki pages:

https://wiki.st.com/stm32mpu/wiki/STM32CubeProgrammer https://wiki.st.com/stm32mpu/wiki/STM32CubeProgrammer_flashlayout

Building the SDK

The SDK for the host system can be build by calling the bitbake command:

bitbake st-image-weston -c populate_sdk

The SDK installer (st-image-weston-openstlinux-weston-<MACHINE_NAME>-x86_64-toolchain-2.6-snapshot.sh) is located in the tmp-glibc/deploy/sdk directory.