26. STMicroelectronics STM32MP1¶
STM32MP1 is a microprocessor designed by STMicroelectronics based on a dual Arm Cortex-A7. It is an Armv7-A platform, using dedicated code from TF-A. The STM32MP1 chip also embeds a Cortex-M4. More information can be found on STM32MP1 Series page.
26.1. Design¶
The STM32MP1 resets in the ROM code of the Cortex-A7. The primary boot core (core 0) executes the boot sequence while secondary boot core (core 1) is kept in a holding pen loop. The ROM code boot sequence loads the TF-A binary image from boot device to embedded SRAM.
The TF-A image must be properly formatted with a STM32 header structure for ROM code is able to load this image. Tool stm32image can be used to prepend this header to the generated TF-A binary.
At compilation step, BL2, BL32 and DTB file are linked together in a single binary. The stm32image tool is also generated and the header is added to TF-A binary. This binary file with header is named tf-a-stm32mp157c-ev1.stm32. It can then be copied in the first partition of the boot device.
26.1.1. Memory mapping¶
0x00000000 +-----------------+
| | ROM
0x00020000 +-----------------+
| |
| ... |
| |
0x2FFC0000 +-----------------+ \
| | |
| ... | |
| | |
0x2FFD8000 +-----------------+ |
| TF-A DTB | | Embedded SRAM
0x2FFDC000 +-----------------+ |
| BL2 | |
0x2FFEF000 +-----------------+ |
| BL32 | |
0x30000000 +-----------------+ /
| |
| ... |
| |
0x40000000 +-----------------+
| |
| | Devices
| |
0xC0000000 +-----------------+ \
| | |
0xC0100000 +-----------------+ |
| BL33 | | Non-secure RAM (DDR)
| ... | |
| | |
0xFFFFFFFF +-----------------+ /
26.1.2. Boot sequence¶
ROM code -> BL2 (compiled with BL2_AT_EL3) -> BL32 (SP_min) -> BL33 (U-Boot)
or if Op-TEE is used:
ROM code -> BL2 (compiled with BL2_AT_EL3) -> OP-TEE -> BL33 (U-Boot)
26.2. Build Instructions¶
To build with SP_min:
make CROSS_COMPILE=arm-linux-gnueabihf- PLAT=stm32mp1 ARCH=aarch32 ARM_ARCH_MAJOR=7 AARCH32_SP=sp_min DTB_FILE_NAME=stm32mp157c-ev1.dtb
cd <u-boot_directory>
make stm32mp15_trusted_defconfig
make DEVICE_TREE=stm32mp157c-ev1 all
To build TF-A with with Op-TEE support:
make CROSS_COMPILE=arm-linux-gnueabihf- PLAT=stm32mp1 ARCH=aarch32 ARM_ARCH_MAJOR=7 AARCH32_SP=optee
The following build options are supported:
ENABLE_STACK_PROTECTOR
: To enable the stack protection.
26.3. Populate SD-card¶
The SD-card has to be formated with GPT. It should contain at least those partitions:
fsbl: to copy the tf-a-stm32mp157c-ev1.stm32 binary
ssbl: to copy the u-boot.stm32 binary
Usually, two copies of fsbl are used (fsbl1 and fsbl2) instead of one partition fsbl.