# # Copyright (C) 2018 STMicroelectronics - All Rights Reserved # # SPDX-License-Identifier: GPL-2.0+ BSD-3-Clause # U-Boot on STMicroelectronics STM32MP1 ====================================== 1. Summary ========== This is a quick instruction for setup stm32mp1 boards. 2. Supported devices ==================== U-Boot supports one STMP32MP1 SoCs: STM32MP157 The STM32MP157 is a Cortex-A MPU aimed at various applications. It features: - Dual core Cortex-A7 application core - 2D/3D image composition with GPU - Standard memories interface support - Standard connectivity, widely inherited from the STM32 MCU family - Comprehensive security support Everything is supported in Linux but U-Boot is limited to: 1. UART 2. SDCard/MMC controller (SDMMC) And the necessary drivers 1. I2C 2. STPMU1 3. Clock, Reset Currently the following boards are supported: + stm32mp157c-ed1 3. Boot Sequences ================= BootRom => FSBL in SYSRAM => SSBL in DDR => OS (Linux Kernel) with FSBL = First Stage Bootloader SSBL = Second Stage Bootloader One boot configuration is supported: The "Basic" boot chain (defconfig_file : stm32mp15_basic_defconfig) BootRom => FSBL = U-Boot SPL => SSBL = U-Boot SPL has limited security initialisation U-Boot is running in secure mode and provide a secure monitor to the kernel with only PSCI support (Power State Coordination Interface defined by ARM) All the STM32MP1 board supported by U-Boot use the same generic board stm32mp1 which support all the bootable devices. Each board is configurated only with the associated device tree. 4. Device Tree Selection ======================== You need to select the appropriate device tree for your board, the supported device trees for stm32mp157 are: + ed1: daughter board with pmic stpmu1 dts: stm32mp157c-ed1 5. Build Procedure ================== 1. Install required tools for U-Boot + install package needed in U-Boot makefile (libssl-dev, swig, libpython-dev...) + install ARMv7 toolchain for 32bit Cortex-A (from Linaro, from SDK for STM32MP1, or any crosstoolchains from your distribution) 2. Set the cross compiler: # export CROSS_COMPILE=/path/to/toolchain/arm-linux-gnueabi- (you can use any gcc cross compiler compatible with U-Boot) 3. Select the output directory (optional) # export KBUILD_OUTPUT=/path/to/output for example: use one output directory for each configuration # export KBUILD_OUTPUT=stm32mp15_basic 4. Configure the U-Boot: # make - For basic boot mode: "stm32mp15_basic_defconfig" 5. Configure the device-tree and build the U-Boot image: # make DEVICE_TREE= all example: basic boot on ed1 # export KBUILD_OUTPUT=stm32mp15_basic # make stm32mp15_basic_defconfig # make DEVICE_TREE=stm32mp157c-ed1 all 6. Output files BootRom and ATF expect binaries with STM32 image header SPL expects file with U-Boot uImage header So in the output directory (selected by KBUILD_OUTPUT), you can found the needed files: + FSBL = spl/u-boot-spl.stm32 + SSBL = u-boot.img 6. Switch Setting for Boot Mode =============================== You can select the boot mode, on the board ed1 with the switch SW1 ----------------------------------- Boot Mode BOOT2 BOOT1 BOOT0 ----------------------------------- Reserved 0 0 0 NOR 0 0 1 SD-Card 1 1 1 SD-Card 1 0 1 eMMC 0 1 0 NAND 0 1 1 Recovery 1 1 0 Recovery 0 0 0 Recovery is a boot from serial link (UART/USB) and it is used with STM32CubeProgrammer tool to load executable in RAM and to update the flash devices available on the board (NOR/NAND/eMMC/SDCARD). The communication between HOST and board is based on - for UARTs : the uart protocol used with all MCU STM32 - for USB : based on USB DFU 1.1 (without the ST extensions used on MCU STM32) 7. Prepare an SDCard =================== The minimal requirements for STMP32MP1 boot up to U-Boot are: - GPT partitioning (with gdisk or with sgdisk) - 2 fsbl partitions, named fsbl1 and fsbl2, size at least 256KiB - one ssbl partition for U-Boot Then the minimal GPT partition is: ----- ------- --------- ------------- | Num | Name | Size | Content | ----- ------- -------- -------------- | 1 | fsbl1 | 256 KiB | ATF or SPL | | 2 | fsbl2 | 256 KiB | ATF or SPL | | 3 | ssbl | enought | U-Boot | | * | - | - | Boot/Rootfs| ----- ------- --------- ------------- (*) add bootable partition for extlinux.conf following Generic Distribution (doc/README.distro for use) according the used card reader select the block device (/dev/sdx or /dev/mmcblk0) in the next example I use /dev/mmcblk0 for example: with gpt table with 128 entries a) remove previous formatting # sgdisk -o /dev/ b) create minimal image # sgdisk --resize-table=128 -a 1 \ -n 1:34:545 -c 1:fsbl1 \ -n 2:546:1057 -c 2:fsbl2 \ -n 3:1058:5153 -c 3:ssbl \ -p /dev/ you can add other partition for kernel (rootfs for example) c) copy the FSBL (2 times) and SSBL file on the correct partition. in this example in partition 1 to 3 for basic boot mode : = /dev/mmcblk0 # dd if=u-boot-spl.stm32 of=/dev/mmcblk0p1 # dd if=u-boot-spl.stm32 of=/dev/mmcblk0p2 # dd if=u-boot.img of=/dev/mmcblk0p3 To boot from SDCard, select BootPinMode = 1 1 1 and reset. 8. Prepare eMMC =============== You can use U-Boot to copy binary in eMMC. In the next example, you need to boot from SDCARD and the images (u-boot-spl.stm32, u-boot.img) are presents on SDCARD (mmc 0) in ext4 partition 4 (bootfs). To boot from SDCard, select BootPinMode = 1 1 1 and reset. Then you update the eMMC with the next U-Boot command : a) prepare GPT on eMMC, example with 2 partitions, bootfs and roots: # setenv emmc_part "name=ssbl,size=2MiB;name=bootfs,type=linux,bootable,size=64MiB;name=rootfs,type=linux,size=512" # gpt write mmc 1 ${emmc_part} b) copy SPL on eMMC on firts boot partition (SPL max size is 256kB, with LBA 512, 0x200) # ext4load mmc 0:4 0xC0000000 u-boot-spl.stm32 # mmc dev 1 # mmc partconf 1 1 1 1 # mmc write ${fileaddr} 0 200 # mmc partconf 1 1 1 0 b) copy U-Boot in first GPT partition of eMMC # ext4load mmc 0:4 0xC0000000 u-boot.img # mmc dev 1 # part start mmc 1 1 partstart # part size mmc 1 1 partsize # mmc write ${fileaddr} ${partstart} ${partsize} To boot from eMMC, select BootPinMode = 0 1 0 and reset.