doc: Add documentation for STM32 MCUs

Add documentation for STM32 MCUs (F4, F7 and H7 series).

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>

2 files changed, 187 insertions, 0 deletions

diff --git a/doc/board/st/index.rst b/doc/board/st/index.rst
index 9bba42f1da..2a8a4ef3b8 100644
--- a/doc/board/st/index.rst
+++ b/doc/board/st/index.rst
@@ -8,3 +8,4 @@ STMicroelectronics
 
    st-dt
    stm32mp1
+   stm32_MCU
diff --git a/doc/board/st/stm32_MCU.rst b/doc/board/st/stm32_MCU.rst
new file mode 100644
index 0000000000..7ff7c730fa
--- /dev/null
+++ b/doc/board/st/stm32_MCU.rst
@@ -0,0 +1,186 @@
+.. SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+.. sectionauthor:: Patrice Chotard <patrice.chotardy@foss.st.com>
+
+STM32 MCU boards
+=================
+
+This is a quick instruction for setup STM32 MCU boards.
+
+Supported devices
+-----------------
+
+U-Boot supports the following STMP32 MCU SoCs:
+
+ - STM32F429
+ - STM32F469
+ - STM32F746
+ - STM32F769
+ - STM32H743
+ - STM32H750
+
+SoCs information:
+-----------------
+STM32F4 series are Cortex-M4 MCU.
+STM32F7 and STM32H7 series are Cortex-M7 MCU.
+
+ + STM32F4 series: https://www.st.com/en/microcontrollers-microprocessors/stm32f4-series.html
+ + STM32F7 series: https://www.st.com/en/microcontrollers-microprocessors/stm32f7-series.html
+ + STM32H7 series: https://www.st.com/en/microcontrollers-microprocessors/stm32h7-series.html
+
+Currently the following boards are supported:
+
+ + stm32f429-discovery
+ + stm32f469-discovery
+ + stm32746g-evaluation
+ + stm32f746-discovery
+ + stm32f769-discovery
+ + stm32h743i-discovery
+ + stm32h743i-evaluation
+ + stm32h750i-art-pi
+
+Boot Sequences
+--------------
+
+For STM32F7 series, 2 boot configurations are supported with and without SPL
+
++------------------------+-------------------------+--------------+
+| **FSBL**               | **SSBL**                | **OS**       |
++------------------------+-------------------------+--------------+
+| First Stage Bootloader | Second Stage Bootloader | Linux Kernel |
++------------------------+-------------------------+--------------+
+| embedded Flash         | DDR                                    |
++------------------------+-------------------------+--------------+
+
+The boot chain with SPL
+```````````````````````
+
+defconfig_file :
+   + **stm32746g-eval_spl_defconfig**
+   + **stm32f746-disco_spl_defconfig**
+   + **stm32f769-disco_spl_defconfig**
+
++------------+------------+-------+
+| FSBL       | SSBL       | OS    |
++------------+------------+-------+
+|U-Boot SPL  | U-Boot     | Linux |
++------------+------------+-------+
+
+The boot chain without SPL
+``````````````````````````
+
+defconfig_file :
+   + **stm32f429-discovery_defconfig**
+   + **stm32f429-evaluation_defconfig**
+   + **stm32f469-discovery_defconfig**
+   + **stm32746g-eval_defconfig**
+   + **stm32f746-disco_defconfig**
+   + **stm32f769-disco_defconfig**
+   + **stm32h743-disco_defconfig**
+   + **stm32h743-eval_defconfig**
+   + **stm32h750-art-pi_defconfig**
+
++-----------+-------+
+| FSBL      | OS    |
++-----------+-------+
+|U-Boot     | Linux |
++-----------+-------+
+
+Build Procedure
+---------------
+
+1. Install the 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 STM32MP15x, or any crosstoolchains from your distribution)
+     (you can use any gcc cross compiler compatible with U-Boot)
+
+2. Set the cross compiler::
+
+   # export CROSS_COMPILE=/path/to/toolchain/arm-linux-gnueabi-
+
+3. Select the output directory (optional)::
+
+   # export KBUILD_OUTPUT=/path/to/output
+
+   for example: use one output directory for each configuration::
+
+   # export KBUILD_OUTPUT=stm32f4
+   # export KBUILD_OUTPUT=stm32f7
+   # export KBUILD_OUTPUT=stm32h7
+
+   you can build outside of code directory::
+
+   # export KBUILD_OUTPUT=../build/stm32f4
+
+4. Configure U-Boot::
+
+   # make <defconfig_file>
+
+   For example with <defconfig_file>:
+
+   - For **stm32f429 discovery** board : **stm32f429-discovery_defconfig**
+   - For **stm32f769 discovery** board with SPL: **stm32f769-disco_spl_defconfig**
+   - For **stm32f769 discovery** board without SPL: **stm32f769-disco_defconfig**
+
+5. Configure the device-tree and build the U-Boot image::
+
+   # make DEVICE_TREE=<name> all
+
+   Examples:
+
+  a) boot with SPL on stm32f746 discovery board::
+
+     # export KBUILD_OUTPUT=stm32f746-disco
+     # make stm32f746-disco_spl_defconfig
+     # make all
+
+  b) boot without SPL on stm32f746 discovery board::
+
+     # export KBUILD_OUTPUT=stm32f746-disco
+     # make stm32f746-disco_defconfig
+     # make all
+
+  c) boot on stm32h743 discovery board::
+
+     # export KBUILD_OUTPUT=stm32h743-disco
+     # make stm32h743-disco_defconfig
+     # make all
+
+  d) boot on stm32h743 evaluation board::
+
+     # export KBUILD_OUTPUT=stm32h743-disco
+     # make stm32h743-eval_defconfig
+     # make all
+
+6. U-Boot Output files
+
+   So in the output directory (selected by KBUILD_OUTPUT),
+   you can found the needed U-Boot files, for example::
+
+     - stm32f746-disco_defconfig = **u-boot-dtb.bin** and **u-boot.dtb**
+
+       - FSBL = u-boot-dtb.bin
+
+     - stm32f746-disco_spl_defconfig = **u-boot-dtb.bin**, **u-boot.dtb** and **u-boot-with-spl.bin**
+
+       - FSBL + SSBL = u-boot-with-spl.bin
+       - SSBL = u-boot-dtb.bin
+
+7. Flash U-Boot files
+
+Plug STM32 MCUs board using the USB ST-Link connector, hence it will expose
+the flash area as a mass-storage. In this mass-storage you will find the
+following files:
+
+- DETAILS.TXT: give the bootrom version and build
+- MBED.HTM: shortcul to the hardware board description web page from st.com.
+
+Copy/paste the u-boot.bin or u-boot-with-spl.bin (in case of bootchain with SPL)
+to this mass-storage. The "COM" LED will blink alternatively red and green during
+the flash process. When done the board will reboot automatically.
+
+In case of boot with SPL, by default SPL will try to load either a Linux
+kernel (falcon mode) or, if the key "c" is maintained pressed, the main U-Boot.