feat(docs): introduce STM32MP2 doc

STM32MP2x is a new family of microprocessors designed by
STMicroelectronics and based on Arm Cortex-A35.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: I741ed0a701a614817a4d0b65d3d6f4e6a79da6a9

docs/plat/st/index.rst

@@ -7,6 +7,7 @@ STMicroelectronics STM32 MPUs
 
    stm32mpus
    stm32mp1
+   stm32mp2
 
 --------------
 

docs/plat/st/stm32mp2.rst

@@ -0,0 +1,133 @@
+STM32MP2
+========
+
+STM32MP2 is a microprocessor designed by STMicroelectronics
+based on Arm Cortex-A35.
+
+For TF-A common configuration of STM32 MPUs, please check
+:ref:`STM32 MPUs` page.
+
+STM32MP2 Versions
+-----------------
+
+The STM32MP25 series is available in 4 different lines which are pin-to-pin compatible:
+
+- STM32MP257: Dual Cortex-A35 cores, Cortex-M33 core - 3x Ethernet (2+1 switch) - 3x CAN FD – H264 - 3D GPU – AI / NN - LVDS
+- STM32MP255: Dual Cortex-A35 cores, Cortex-M33 core - 2x Ethernet – 3x CAN FD - H264 - 3D GPU – AI / NN - LVDS
+- STM32MP253: Dual Cortex-A35 cores, Cortex-M33 core - 2x Ethernet – 3x CAN FD - LVDS
+- STM32MP251: Single Cortex-A35 core, Cortex-M33 core - 1x Ethernet
+
+Each line comes with a security option (cryptography & secure boot) and a Cortex-A frequency option:
+
+- A      Basic + Cortex-A35 @ 1GHz
+- C      Secure Boot + HW Crypto + Cortex-A35 @ 1GHz
+- D      Basic + Cortex-A35 @ 1.5GHz
+- F      Secure Boot + HW Crypto + Cortex-A35 @ 1.5GHz
+
+Memory mapping
+--------------
+
+::
+
+    0x00000000 +-----------------+
+               |                 |
+               |       ...       |
+               |                 |
+    0x0E000000 +-----------------+ \
+               |       BL31      | |
+               +-----------------+ |
+               |       ...       | |
+    0x0E012000 +-----------------+ |
+               |     BL2 DTB     | | Embedded SRAM
+    0x0E016000 +-----------------+ |
+               |       BL2       | |
+    0x0E040000 +-----------------+ /
+               |                 |
+               |       ...       |
+               |                 |
+    0x40000000 +-----------------+
+               |                 |
+               |                 |   Devices
+               |                 |
+    0x80000000 +-----------------+ \
+               |                 | |
+               |                 | | Non-secure RAM (DDR)
+               |                 | |
+    0xFFFFFFFF +-----------------+ /
+
+
+Build Instructions
+------------------
+
+STM32MP2x specific flags
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Dedicated STM32MP2 build flags:
+
+- | ``STM32MP_DDR_FIP_IO_STORAGE``: to store DDR firmware in FIP.
+  | Default: 1
+- | ``STM32MP25``: to select STM32MP25 variant configuration.
+  | Default: 1
+
+To compile the correct DDR driver, one flag must be set among:
+
+- | ``STM32MP_DDR3_TYPE``: to compile DDR3 driver and DT.
+  | Default: 0
+- | ``STM32MP_DDR4_TYPE``: to compile DDR4 driver and DT.
+  | Default: 0
+- | ``STM32MP_LPDDR4_TYPE``: to compile LpDDR4 driver and DT.
+  | Default: 0
+
+
+Boot with FIP
+~~~~~~~~~~~~~
+You need to build BL2, BL31, BL32 (OP-TEE) and BL33 (U-Boot) before building FIP binary.
+
+U-Boot
+______
+
+.. code:: bash
+
+    cd <u-boot_directory>
+    make stm32mp25_defconfig
+    make DEVICE_TREE=stm32mp257f-ev1 all
+
+OP-TEE
+______
+
+.. code:: bash
+
+    cd <optee_directory>
+    make CROSS_COMPILE64=aarch64-none-elf- CROSS_COMPILE32=arm-none-eabi-
+        ARCH=arm PLATFORM=stm32mp2 \
+        CFG_EMBED_DTB_SOURCE_FILE=stm32mp257f-ev1.dts
+
+TF-A BL2 & BL31
+_______________
+To build TF-A BL2 with its STM32 header and BL31 for SD-card boot:
+
+.. code:: bash
+
+    make CROSS_COMPILE=aarch64-none-elf- PLAT=stm32mp2 \
+        STM32MP_DDR4_TYPE=1 SPD=opteed \
+        DTB_FILE_NAME=stm32mp257f-ev1.dtb STM32MP_SDMMC=1
+
+For other boot devices, you have to replace STM32MP_SDMMC in the previous command
+with the desired device flag.
+
+
+FIP
+___
+
+.. code:: bash
+
+    make CROSS_COMPILE=aarch64-none-elf- PLAT=stm32mp2 \
+        STM32MP_DDR4_TYPE=1 SPD=opteed \
+        DTB_FILE_NAME=stm32mp257f-ev1.dtb \
+        BL33=<u-boot_directory>/u-boot-nodtb.bin \
+        BL33_CFG=<u-boot_directory>/u-boot.dtb \
+        BL32=<optee_directory>/tee-header_v2.bin \
+        BL32_EXTRA1=<optee_directory>/tee-pager_v2.bin
+        fip
+
+*Copyright (c) 2023, STMicroelectronics - All Rights Reserved*

docs/plat/st/stm32mpus.rst

@@ -4,7 +4,7 @@ STM32 MPUs
 STM32 MPUs are microprocessors designed by STMicroelectronics
 based on Arm Cortex-A. This page presents the common configuration of STM32
 MPUs, more details and dedicated configuration can be found in each STM32 MPU
-page (:ref:`STM32MP1`)
+page (:ref:`STM32MP1` or :ref:`STM32MP2`)
 
 Design
 ------