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

Configuration files:

• defconfig file
  • configs/stm32mp15_defconfig when FIP is used in OpenSTLinux
• config files
• include/configs/stm32mp15_common.h : generic for STM32MP15x lines 
• include/configs/stm32mp15_st_common.h : STMicroelectronics board for STM32MP15x lines 
• 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

Warning

The U-Boot defconfig to use for ecosystem release ≥ <span title="Main software components: unknown revision unknown revision unknown revision unknown revision unknown revision unknown revision unknown revision">v4.0.0 change to stm32mp15_defconfig.

The two next defconfig are kept only for compatibility with upstream, don't use them:

• configs/stm32mp15_trusted_defconfig with stm32 image header support (CONFIG_STM32MP15x_STM32IMAGE)
• configs/stm32mp15_basic_defconfig when SPL is used

2. Selecting targets : choose defconfig and device tree

The STM32 MPU boot chain is supported by one U-Boot configuration with defconfig = stm32mp15_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_defconfig

 PC $> make stm32mp15_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.

Note: All the compiled device trees 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 u-boot.stm32' is only generated for stm32mp15_trusted_defconfig with CONFIG_STM32MP15x_STM32IMAGE; it is not more used for ecosystem release ≥ <span title="Main software components: unknown revision unknown revision unknown revision unknown revision unknown revision unknown revision unknown revision">v4.0.0 .

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 :

 PC $> fiptool --verbose update --nt-fw u-boot-nodtb.bin \
             --hw-config  u-boot.dtb \
             fip-<board>.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

See How_to_configure_TF-A_FIP for details.

5. Examples

5.1. STM32MP157F-EV1 Evaluation board

 PC $> make stm32mp15_defconfig
 PC $> make DEVICE_TREE=stm32mp157f-ev1 all

An existing FIP file is updated with:

 PC $> fiptool --verbose update --nt-fw u-boot-nodtb.bin --hw-config u-boot.dtb \
              fip-stm32mp157f-ev1.bin

5.2. STM32MP157C-EV1 Evaluation board

 PC $> make stm32mp15_defconfig
 PC $> make DEVICE_TREE=stm32mp157c-ev1 all

An existing FIP file is updated with:

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

5.3. STM32MP157D-DK1 Discovery kit

 PC $> make stm32mp15_defconfig
 PC $> make DEVICE_TREE=stm32mp157d-dk1 all

An existing FIP file is updated with:

 PC $> fiptool --verbose update --nt-fw u-boot-nodtb.bin --hw-config u-boot.dtb \
              fip-stm32mp157d-dk1.bin

5.4. STM32MP157C-DK2 Discovery kit

Using export to select the device tree

 PC $> export KBUILD_OUTPUT=../build/stm32mp15
 PC $> export DEVICE_TREE=stm32mp157c-dk2
 PC $> make stm32mp15_defconfig
 PC $> make all

An existing FIP file is updated with:

 PC $> fiptool --verbose update --nt-fw $KBUILD_OUTPUT/u-boot-nodtb.bin \
              --hw-config  $KBUILD_OUTPUT/u-boot.dtb \
              fip-stm32mp157c-dk2.bin

5.5. Custom board with external device tree

 PC $> make stm32mp15_defconfig
 PC $> make EXT_DTB=stm32mp151a-myboard.dtb all

Then you can create or update the FIP