STM32MP15 U-Boot

Applicable for

STM32MP15x lines

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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.

Also available in official U-Boot Git.

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.15x : specific configuration for STM32MP15x lines 
• board/st/common : STMicroelectronics common code
• board/st/stm32mp1 : generic STMicroelectronics board for STM32MP1 Series
• drivers/*/*stm32* : drivers

Configuration Files:

• defconfig file
  • configs/stm32mp15_trusted_defconfig
  • configs/stm32mp15_basic_defconfig
• config files
  • include/configs/stm32mp1.h
• STM32_MPU_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

 PC $> make stm32mp15_trusted_defconfig
 PC $> 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.

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

The ouput file is u-boot.stm32 for ecosystem release ≤ v2.1.0 or if you activate CONFIG_STM32MP15x_STM32IMAGE in your defconfig for ecosystem release ≥ v3.0.0 (this temporary option is only introduced to facilitate the FIP migration but it will be removed in the next EcosystemRelease).

With FIP support for ecosystem release ≥ v3.0.0 , the offset on U-Boot environment in NOR are defined in the defconfig with:

 CONFIG_ENV_OFFSET=0x480000
 CONFIG_ENV_OFFSET_REDUND=0x4C0000

Without FIP support these MTD partition offsets in NOR for default flashlayout change and to reuse the ecosystem release ≤ v2.1.0 flashlayout the defconfig options become:

 CONFIG_STM32MP15x_STM32IMAGE=y
 CONFIG_ENV_OFFSET=0x280000
 CONFIG_ENV_OFFSET_REDUND=0x2C0000

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 upddate of STM32MP157C-EV1 Evaluation board :

 PC $> fiptool --verbose update --nt-fw u-boot-nodtb.bin \
             --hw-config  u-boot.dtb \
             tf-a-fip-stm32mp157c-ev1.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

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5. SPL compilation

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

With the defconfig file: stm32mp15_basic_defconfig

 PC $> make stm32mp15_basic_defconfig
 PC $> make DEVICE_TREE=<Device tree> all

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.

6. Examples

6.1. STM32MP157F-EV1 Evaluation board

 PC $> make stm32mp15_trusted_defconfig
 PC $> make DEVICE_TREE=stm32mp157f-ev1 all

6.2. STM32MP157C-EV1 Evaluation board

 PC $> make stm32mp15_trusted_defconfig
 PC $> make DEVICE_TREE=stm32mp157c-ev1 all

6.3. STM32MP157D-DK1 Discovery kit

 PC $> make stm32mp15_trusted_defconfig
 PC $> make DEVICE_TREE=stm32mp157d-dk1 all

6.4. STM32MP157C-DK2 Discovery kit

Using export to select the device tree

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

6.5. Custom board with external device tree

 PC $> make stm32mp15_trusted_defconfig
 PC $> make EXT_DTB=stm32mp151a-myboard.dtb all

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6.6. SPL for STM32MP157F-EV1 Evaluation board

 PC $> make stm32mp15_basic_defconfig
 PC $> make DEVICE_TREE=stm32mp157f-ev1 all