Support for the SoC is still in progress, but lets document
what we have now.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
Documentation/boards/stm32mp.rst | 73 ++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
create mode 100644 Documentation/boards/stm32mp.rst
diff --git a/Documentation/boards/stm32mp.rst b/Documentation/boards/stm32mp.rst
new file mode 100644
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+++ b/Documentation/boards/stm32mp.rst
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+STMicroelectronics STM32MP
+==========================
+
+.. note::
+
+ Support for the STM32MP architecure in barebox is still in progress.
+ Bootstrapping an OS from mainline barebox is not yet supported.
+
+The STM32MP is a line of 32-bit ARM SoCs. They reuse peripherals of the
+STM32 line of microcontrollers and can have a STM32 MCU embedded as co-processor
+as well.
+
+The boot process of the STM32MP SoC is a two step process.
+The first stage boot loader (FSBL) is loaded by the ROM code into the built-in
+SYSRAM and executed. The FSBL sets up the SDRAM, install a secure monitor and
+then the second stage boot loader (SSBL) is loaded into DRAM.
+
+When building barebox, the resulting ``barebox-${board}.img`` file has the STM32
+header preprended, so it can be loaded directly as FSBL by the ARM TF-A
+(https://github.com/ARM-software/arm-trusted-firmware). Each entry point has a
+header-less image ending in ``*.pblb`` as well.
+
+Use of barebox as FSBL is not supported.
+
+Following boards are currently supported in barebox:
+
+Building barebox
+----------------
+
+With multi-image and device trees, it's expected to have ``stm32mp_defconfig``
+as sole defconfig for all STM32MP boards::
+
+ make ARCH=arm stm32mp_defconfig
+
+The resulting images will be placed under ``images/``:
+
+::
+
+ barebox-stm32mp157c-dk2.img
+
+
+Flashing barebox
+----------------
+
+An appropriate image for the boot media can be generated with following
+``genimage(1)`` config::
+
+ image @STM32MP_BOARD@.img {
+ hdimage {
+ align = 1M
+ gpt = "true"
+ }
+ partition fsbl1 {
+ image = "tf-a-@STM32MP_BOARD@.stm32"
+ size = 256K
+ }
+ partition fsbl2 {
+ image = "tf-a-@STM32MP_BOARD@.stm32"
+ size = 256K
+ }
+ partition ssbl {
+ image = "barebox-@STM32MP_BOARD@.img"
+ size = 1M
+ }
+ }
+
+Image can then be flashed on e.g. a SD-Card.
+
+TODO
+----
+
+* Extend barebox MMCI support to support the SDMMC2
+* Extend barebox DesignWare MAC support to support the stmmac
--
2.20.1
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