# STM32MP257F-DK Study
## Why choose STM32MP257F-DK?
* From hardware perspectives
* Support heterogeneous computing
* Primary Processor: ARM Cortex‑A35 (dual-core)
* Coprocessor: ARM Cortex‑M33 (single-core)
* Support ARM trusted firmware: [Boot chain overview](https://wiki.st.com/stm32mpu/wiki/STM32MP2_boot_chain_overview)
* BL1: BootROM
* BL2: TF-A
* BL31: TF-A
* BL32: OP-TEE
* BL33: U-Boot
* Non-Secure OS: Linux
* From software perspectives
* STM32 provides well-written docs.
* STM32 community is very active.
## Where to order?
You can order it from different sources in Taiwan.
* [Mouser](https://mou.sr/4a4fPQv)
* [DigiKey](https://www.digikey.tw/short/42trdf03)
## Enviroment Setup
* PC
1. Install [Ubuntu 24.04.3 LTS](https://documentation.ubuntu.com/desktop/en/latest/tutorial/install-ubuntu-desktop/#install-ubuntu-desktop) on your PC.
2. Disable [GRUB_DISABLE_OS_PROBER](https://askubuntu.com/questions/1475735/check-grub-disable-os-prober) if dual boot like Win+Ubuntu is needed.
3. Follow [stm32mpu wiki: PC prerequisites](https://wiki.st.com/stm32mpu/wiki/PC_prerequisites) to install packages.
4. Follow [stm32mpu wiki: directory structure](https://wiki.st.com/stm32mpu/wiki/Example_of_directory_structure_for_Packages) to create your working directory.

     working-directory
     ├── Developer-Package
     │   ├── en.SOURCES-stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27.tar.gz
     │   ├── SDK-x86_64-stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11.tar.gz
     │   ├── stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11
     │   │   ├── sdk
     │   │   └── sources
     │   │       ├── cli_hello_world_example
     │   │       └── gtk_hello_world_example
     │   └── stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27
     │       └── sources
     │           └── ostl-linux
     └── Starter-Package
         ├── FLASH-stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11.tar.gz
         └── stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11
             └── images
                 └── stm32mp2

## Starter Package: STM32 official images
The following steps are for Arm Cortex-A35 flavor.
1. Follow [stm32mpu wiki: images](https://wiki.st.com/stm32mpu/wiki/Getting_started/STM32MP2_boards/STM32MP257x-DK/Let%27s_start/Populate_the_target_and_boot_the_image) to flash the board and bring Linux (i.e. OpenSTLinux - Weston) up from the SD card.
2. Follow [stm32mpu wiki: basic commands](https://wiki.st.com/stm32mpu/wiki/Getting_started/STM32MP2_boards/STM32MP257x-DK/Let%27s_start/Execute_basic_commands) to interact with the board.

# UART  
minicom -D /dev/ttyACM0

# SSH
ssh root@192.168.7.1

## Developer Package
The following steps are for Arm Cortex-A35 flavor.
### Source Code
#### Board Support Package (BSP)
Follow [stm32mpu wiki: BSP](https://wiki.st.com/stm32mpu/wiki/STM32MPU_Developer_Package#Installing_the_OpenSTLinux_BSP_packages) to fetch and extract the source code.

cd Developer-Package
tar xvf en.SOURCES-stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27.tar.gz

#### Software Development Kit (SDK)
1. Follow [stm32mpu wiki: install SDK](https://wiki.st.com/stm32mpu/wiki/Getting_started/STM32MP2_boards/STM32MP257x-DK/Develop_on_Arm_Cortex-A35/Install_the_SDK) to fetch and extract the source code.

   cd Developer-Package/
   tar xvf SDK-x86_64-stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11.tar.gz

2. Souce the environmemt script

      cd Developer-Package/
      source stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11/sdk/environment-setup-cortexa35-ostl-linux

### User-space Applications
* GUI hello-world
Follow [stm32mpu wiki: GUI hello-world](https://wiki.st.com/stm32mpu/wiki/Getting_started/STM32MP2_boards/STM32MP257x-DK/Develop_on_Arm_Cortex-A35/Create_a_simple_hello-world_application) to build and deploy the GUI hello world application.

  cd Developer-Package/stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11/sources/gtk_hello_world_example/
  make
  scp gtk_hello_world root@192.168.7.1:/usr/local

* CLI hello-world
Follow [stm32mpu wiki: CLI hello-world](https://wiki.st.com/stm32mpu/wiki/How_to_cross-compile_with_the_Developer_Package#Adding_a_-22hello_world-22_user_space_example) to build and deploy the CLI hello world application.

  cd Developer-Package/stm32mp2-openstlinux-6.6-yocto-scarthgap-mpu-v25.06.11/sources/cli_hello_world_example/
  make
  scp hello_world_example root@192.168.7.1:/usr/local

### Linux Kernel
1. Follow [stm32mpu wiki: Kernel](https://wiki.st.com/stm32mpu/wiki/Cross-compile_with_OpenSTLinux_SDK#Modifying_the_Linux_kernel) to fetch Linux Kernel source code.

   cd Developer-Package/stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0
   git clone https://github.com/STMicroelectronics/linux.git
   cd linux
   git checkout -b WORKING v6.6-stm32mp-r2

2. Create output directory

   cd Developer-Package/stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0/linux/
   export OUTPUT_BUILD_DIR=$PWD/../build
   mkdir -p ${OUTPUT_BUILD_DIR}

3. Config Kernel

   cd Developer-Package/stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0/linux/
   make O="${OUTPUT_BUILD_DIR}" defconfig fragment*.config
   for f in `ls -1 ../fragment*.config`; do scripts/kconfig/merge_config.sh -m -r -O ${OUTPUT_BUILD_DIR} ${OUTPUT_BUILD_DIR}/.config $f; done
   (yes '' || true) | make oldconfig O="${OUTPUT_BUILD_DIR}"

4. Build Kernel, DTB and modules

   cd Developer-Package/stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/linux-stm32mp-6.6.78-stm32mp-r2-r0/linux/
   make Image.gz vmlinux dtbs modules compile_commands.json O="${OUTPUT_BUILD_DIR}"

5. Deploy Kernel and DTB

   mkdir -p ${OUTPUT_BUILD_DIR}/install_artifact/boot/
   cp ${OUTPUT_BUILD_DIR}/arch/${ARCH}/boot/Image.gz ${OUTPUT_BUILD_DIR}/install_artifact/boot/
   find ${OUTPUT_BUILD_DIR}/arch/${ARCH}/boot/dts/ -name 'st*.dtb' -exec cp '{}' ${OUTPUT_BUILD_DIR}/install_artifact/boot/ \;
   scp -r ${OUTPUT_BUILD_DIR}/install_artifact/boot/* root@192.168.7.1:/boot/

6. Deploy modules

   make INSTALL_MOD_PATH="${OUTPUT_BUILD_DIR}/install_artifact" modules_install O="${OUTPUT_BUILD_DIR}"
   rm -f ${OUTPUT_BUILD_DIR}/install_artifact/lib/modules/6.6.78-gf01241fbba4d/build
   scp -r ${OUTPUT_BUILD_DIR}/install_artifact/lib/modules/* root@192.168.7.1:/lib/modules/
   ssh root@192.168.7.1 /sbin/depmod -a

7. Reboot the board

   ssh root@192.168.7.1 sync
   ssh root@192.168.7.1 reboot

### BL33: U-Boot
1. Follow [stm32mpu wiki: U-Boot](https://wiki.st.com/stm32mpu/wiki/Cross-compile_with_OpenSTLinux_SDK#Modifying_the_U-Boot) to fetch the source code.

   cd Developer-Package/stm32mp-openstlinux-6.6-yocto-scarthgap-mpu-v25.08.27/sources/ostl-linux/u-boot-stm32mp-v2023.10-stm32mp-r2-r0
   git clone https://github.com/STMicroelectronics/u-boot.git
   cd u-boot
   git checkout -b WORKING v2023.10-stm32mp-r2

2. TBD