STM32MP15 U-Boot

This article briefly describes the STM32MP15x lines  support in U-Boot.

1 STM32MP15x lines  support

For detailed information, please read the file in the delivered U-Boot code = doc/board/st/stm32mp1.rst or the stm32mp1 documentation generated by make htlmdocs^[1].

Also available in official U-Boot Git.

Code :

• arch/arm/mach-stm32mp : arch specific code for STM32 Arm^®Cortex^® MPUs 
• board/st/common : STMicroelectronics common code
• board/st/stm32mp1 : generic STMicroelectronics board for STM32MP1 series
• drivers/*/*stm32* : drivers

Configuration Files:

• defconfig file
  • configs/stm32mp15_basic_defconfig
  • configs/stm32mp15_trusted_defconfig
• config files
  • include/configs/stm32mp1.h
• STM32MP15_device_tree in arch/arm/dts  : stm32mp15*.dts*
  • <Device tree>.dts : same as kernel
  • <Device tree>-u-boot.dtsi : addition for u-boot automatically included in build process

2 Selecting targets : choose defconfig and Device Tree

The STM32 MPU boot chain is supported by one U-Boot configuration with defconfig = stm32mp15_trusted_defconfig

Several boards are supported with the associated device-tree (same name as kernel):

Board part number	Device tree	Description
STM32MP157A-EV1 Evaluation board	stm32mp157a-ev1	MB1262+MB1263
STM32MP157C-EV1 Evaluation board	stm32mp157c-ev1
STM32MP157D-EV1 Evaluation board	stm32mp157d-ev1
STM32MP157F-EV1 Evaluation board	stm32mp157f-ev1
STM32MP157A-DK1 Discovery kit	stm32mp157a-dk1	MB1272
STM32MP157D-DK1 Discovery kit	stm32mp157d-dk1
STM32MP157C-DK2 Discovery kit	stm32mp157c-dk2	MB1272+MB1407
STM32MP157F-DK2 Discovery kit	stm32mp157f-dk2

For information the 'Evaluation' daughter-board only (MB1263 without MB1262) is also supported by stm32mp15*-ed1.dts device tree files.

3 Compilation

see U-Boot_overview#U-Boot_build

With the defconfig file: stm32mp15_trusted_defconfig

  make stm32mp15_trusted_defconfig
  make DEVICE_TREE=<Device tree> all

The supported variables are:

• DEVICE_TREE: select in arch/arm/dts the device tree that is used
• KBUILD_OUTPUT: change the destination directory for the build
• EXT_DTB: select external device tree

The ouput file is u-boot.stm32.

4 SPL compilation

The alternate boot chain with SPL is also supported by "stm32mp15_basic_defconfig" but only for U-Boot_SPL:_DDR_interactive_mode

The resulting U-Boot files are located in your build directory:

• u-boot-spl.stm32 : FSBL = SPL binary with STM32 image header, loaded by ROM code
• u-boot.img : SSBL = U-Boot binary with U-Boot image header (uImage), loaded by SPL

Warning

This alternate boot chain with SPL is not supported/promoted by STMicroelectronics to make product.

5 Examples

5.1 STM32MP157F-EV1 Evaluation board

  make stm32mp15_trusted_defconfig
  make DEVICE_TREE=stm32mp157f-ev1 all

5.2 STM32MP157C-EV1 Evaluation board

  make stm32mp15_trusted_defconfig
  make DEVICE_TREE=stm32mp157c-ev1 all

5.3 STM32MP157D-DK1 Discovery kit

  make stm32mp15_trusted_defconfig
  make DEVICE_TREE=stm32mp157d-dk1 all

5.4 STM32MP157C-DK2 Discovery kit

Using export to select the device tree

  export KBUILD_OUTPUT=../build/stm32mp15_trusted
  export DEVICE_TREE=stm32mp157c-dk2
  make stm32mp15_trusted_defconfig
  make all

5.5 Custom board with external device tree

  make stm32mp15_trusted_defconfig
  make EXT_DTB=stm32mp151a-myboard.dtb all

5.6 SPL for STM32MP157F-EV1 Evaluation board

  make stm32mp15_basic_defconfig
  make DEVICE_TREE=stm32mp157f-ev1 all