SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
#
# Copyright (C) 2018 STMicroelectronics - All Rights Reserved
#
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. STPMIC1 (PMIC and regulator)
3. Clock, Reset, Sysreset
4. Fuse
Currently the following boards are supported:
+ stm32mp157c-ev1
+ stm32mp157c-ed1
+ stm32mp157a-dk1
+ stm32mp157c-dk2
3. Boot Sequences
=================
BootRom => FSBL in SYSRAM => SSBL in DDR => OS (Linux Kernel)
with FSBL = First Stage Bootloader
SSBL = Second Stage Bootloader
2 boot configurations are supported:
1) The "Trusted" boot chain (defconfig_file : stm32mp15_trusted_defconfig)
BootRom => FSBL = Trusted Firmware-A (TF-A) => SSBL = U-Boot
TF-A performs a full initialization of Secure peripherals and installs a
secure monitor.
U-Boot is running in normal world and uses TF-A monitor
to access to secure resources
2) 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 boards 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:
+ ev1: eval board with pmic stpmic1 (ev1 = mother board + daughter ed1)
dts: stm32mp157c-ev1
+ ed1: daughter board with pmic stpmic1
dts: stm32mp157c-ed1
+ dk1: Discovery board
dts: stm32mp157a-dk1
+ dk2: Discovery board = dk1 with a BT/WiFI combo and a DSI panel
dts: stm32mp157c-dk2
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_trusted
# export KBUILD_OUTPUT=stm32mp15_basic
4. Configure U-Boot:
# make <defconfig_file>
- For trusted boot mode : "stm32mp15_trusted_defconfig"
- For basic boot mode: "stm32mp15_basic_defconfig"
5. Configure the device-tree and build the U-Boot image:
# make DEVICE_TREE=<name> all
example:
a) trusted boot on ev1
# export KBUILD_OUTPUT=stm32mp15_trusted
# make stm32mp15_trusted_defconfig
# make DEVICE_TREE=stm32mp157c-ev1 all
b) basic boot on ev1
# export KBUILD_OUTPUT=stm32mp15_basic
# make stm32mp15_basic_defconfig
# make DEVICE_TREE=stm32mp157c-ev1 all
c) basic boot on ed1
# export KBUILD_OUTPUT=stm32mp15_basic
# make stm32mp15_basic_defconfig
# make DEVICE_TREE=stm32mp157c-ed1 all
d) basic boot on dk2
# export KBUILD_OUTPUT=stm32mp15_basic
# make stm32mp15_basic_defconfig
# make DEVICE_TREE=stm32mp157c-dk2 all
6. Output files
BootRom and TF-A 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:
a) For Trusted boot
+ FSBL = tf-a.stm32 (provided by TF-A compilation)
+ SSBL = u-boot.stm32
b) For Basic boot
+ 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 0 1
eMMC 0 1 0
NAND 0 1 1
Recovery 1 1 0
Recovery 0 0 0
- on board DK1/DK2 with the switch SW1 : BOOT0, BOOT2
(BOOT1 forced to 0, NOR not supported)
--------------------------
Boot Mode BOOT2 BOOT0
--------------------------
Reserved 1 0
SD-Card 1 1
Recovery 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 | TF-A or SPL |
| 2 | fsbl2 | 256 KiB | TF-A 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/<SDCard 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/<SDCard dev>
you can add other partitions for kernel
one partition rootfs for example:
-n 4:5154: -c 4:rootfs \
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 : <SDCard dev> = /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
for trusted boot mode :
# dd if=tf-a.stm32 of=/dev/mmcblk0p1
# dd if=tf-a.stm32 of=/dev/mmcblk0p2
# dd if=u-boot.stm32 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 0 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
c) 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.
9. MAC Address
==============
Please read doc/README.enetaddr for the implementation guidelines for mac id
usage. Basically, environment has precedence over board specific storage.
Mac id storage and retrieval in stm32mp otp :
- OTP_57[31:0] = MAC_ADDR[31:0]
- OTP_58[15:0] = MAC_ADDR[47:32]
To program a MAC address on virgin OTP words above, you can use the fuse command
on bank 0 to access to internal OTP:
example to set mac address "12:34:56:78:9a:bc"
1- Write OTP
STM32MP> fuse prog -y 0 57 0x78563412 0x0000bc9a
2- Read OTP
STM32MP> fuse sense 0 57 2
Sensing bank 0:
Word 0x00000039: 78563412 0000bc9a
3- next REBOOT :
### Setting environment from OTP MAC address = "12:34:56:78:9a:bc"
4 check env update
STM32MP> print ethaddr
ethaddr=12:34:56:78:9a:bc
6fe7dd3327