STM32MP13 U-Boot

Applicable for

STM32MP13x lines

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This article briefly describes the STM32MP13x lines  support in U-Boot.

1. STM32MP13x lines  support

For detailed information, read the file in the delivered U-Boot code = doc/board/st/stm32mp1.rst or the documentation generated by make htlmdocs: board/st/stm32mp1.html.

Code:

• arch/arm/mach-stm32mp : arch specific code for STM32 Arm^® Cortex^® MPUs 
  • arch/arm/mach-stm32mp/Kconfig : generic configuration for STM32 Arm^® Cortex^® MPUs 
  • arch/arm/mach-stm32mp/Kconfig.13x : specific configuration for STM32MP13x lines 
• board/st/common : STMicroelectronics common code
• board/st/stm32mp1 : STMicroelectronics boards support for STM32MP1 Series
• drivers/*/*stm32* : drivers

Configuration files:

• defconfig file
  • configs/stm32mp13_defconfig
• config files
  • include/configs/stm32mp13_common.h : generic for STM32MP13x lines 
  • include/configs/stm32mp13_st_common.h : STMicroelectronics board for STM32MP13x lines 
• STM32_MPU_device_tree in arch/arm/dts : stm32mp13*.dts*
  • <Device tree>.dts: same as kernel
  • <Device tree>-u-boot.dtsi: addition for u-boot automatically included in build process
  • stm32mp13-u-boot.dtsi : SoC add-on file included in <Device tree>-u-boot.dtsi

2. Selecting targets: choose defconfig and device tree

The U-Boot configuration with defconfig is stm32mp13_defconfig.

The STM32MP13 boards are supported with the associated device tree (same name as kernel):

Board part number	Device tree	Description
STM32MP135F-DK Discovery kit	stm32mp135f-dk	MB1635

3. Compilation

see U-Boot_overview#U-Boot_build

For STM32MP135F-DK Discovery kit , the device tree is already selected in defconfig stm32mp13_defconfig

  make stm32mp13_defconfig
  make all

For other boards, you need to select the correct device tree

  make stm32mp13_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 output files u-boot.dtb and u-boot-nodtb.bin are integrated in FIP.

Note: All the compiled devices trees are available in $KBUILD_OUTPUT/arch/arm/dts/*.dtb.
You can select them instead of u-boot.dtb without U-Boot recompilation.

4. U-Boot integration in FIP

U-Boot binary and its associated device tree are part of the FIP binary, created with TF-A Makefile option:

• BL33_CFG = u-boot.dtb
• BL33 = u-boot-nodtb.bin

or updated with fiptools:

• --hw-config u-boot.dtb
• --nt-fw u-boot-nodtb.bin

Example for FIP update of STM32MP135F-DK Discovery kit :

  fiptool --verbose update --nt-fw u-boot-nodtb.bin \
             --hw-config  u-boot.dtb \
             fip-stm32mp135f-dk.bin
 
 DEBUG: Replacing nt-fw with .../u-boot-nodtb.bin
 DEBUG: Replacing hw-config with .../u-boot.dtb
 DEBUG: Metadata size: ... bytes
 DEBUG: Payload size: ... bytes

5. Examples

5.1. STM32MP135F-DK Discovery kit

  make stm32mp13_defconfig
  make  all

or

  make stm32mp13_defconfig
  make DEVICE_TREE=stm32mp135f-dk all

and

  fiptool --verbose update --nt-fw u-boot-nodtb.bin  --hw-config u-boot.dtb \
                        fip-stm32mp135f-dk.bin

5.2. STM32MP135F-DK Discovery kit with export

  export KBUILD_OUTPUT=../build/stm32mp13
  export DEVICE_TREE=stm32mp135f-dk
  make stm32mp13_defconfig
  make all

  fiptool --verbose update --nt-fw $KBUILD_OUTPUT/u-boot-nodtb.bin \
             --hw-config  $KBUILD_OUTPUT/u-boot.dtb \
             fip-stm32mp135f-dk.bin

5.3. Custom board with external device tree

  make stm32mp13_defconfig
  make EXT_DTB=stm32mp131a-myboard.dtb all

  fiptool --verbose update --nt-fw u-boot-nodtb.bin \
             --hw-config  u-boot.dtb \
             fip-stm32mp131a-myboard.bin