Trusted Firmware-A for 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. 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. 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 +-----------------+ / 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) Build Instructions ------------------ To build with SP_min: .. code:: bash 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 make stm32mp15_basic_defconfig make DEVICE_TREE=stm32mp157c-ev1 all ./tools/mkimage -T stm32image -a 0xC0100000 -e 0xC0100000 -d u-boot.bin u-boot.stm32 To build TF-A with with Op-TEE support: .. code:: bash 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. 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. .. _STM32MP1 Series: https://www.st.com/en/microcontrollers-microprocessors/stm32mp1-series.html