This is a quick instruction for setup STM32MP15x boards.
+Futher information can be found in STMicrolectronics STM32 WIKI_.
+
Supported devices
-----------------
Boot Sequences
--------------
-3 boot configurations are supported with:
+2 boot configurations are supported with:
+----------+------------------------+-------------------------+--------------+
| **ROM** | **FSBL** | **SSBL** | **OS** |
| | embedded RAM | DDR |
+----------+------------------------+-------------------------+--------------+
-The **Trusted** boot chain
-``````````````````````````
-
-defconfig_file : stm32mp15_trusted_defconfig
+The **Trusted** boot chain with TF-A_
+`````````````````````````````````````
- +-------------+-------------------------+------------+-------+
- | ROM code | FSBL | SSBL | OS |
- + +-------------------------+------------+-------+
- | |Trusted Firmware-A (TF-A)| U-Boot | Linux |
- +-------------+-------------------------+------------+-------+
- | TrustZone |secure monitor |
- +-------------+-------------------------+------------+-------+
+defconfig_file :
+ + **stm32mp15_defconfig** (for TF-A_ with FIP support)
+ + **stm32mp15_trusted_defconfig** (for TF-A_ without FIP support)
-TF-A performs a full initialization of Secure peripherals and installs a
-secure monitor, BL32:
+ +-------------+--------------------------+------------+-------+
+ | ROM code | FSBL | SSBL | OS |
+ + +--------------------------+------------+-------+
+ | |Trusted Firmware-A (TF-A_)| U-Boot | Linux |
+ +-------------+--------------------------+------------+-------+
+ | TrustZone |secure monitor = SPMin or OP-TEE_ |
+ +-------------+--------------------------+------------+-------+
- * SPMin provided by TF-A or
- * OP-TEE from specific partitions (teeh, teed, teex).
+TF-A_ and OP-TEE_ are 2 separate projects, with their git repository;
+they are compiled separately.
-U-Boot is running in normal world and uses the secure monitor to access
-to secure resources.
+TF-A_ (BL2) initialize the DDR and loads the next stage binaries from a FIP file:
+ + BL32: a secure monitor BL32 = SPMin provided by TF-A_ or OP-TEE_ :
+ performs a full initialization of Secure peripherals and provides service
+ to normal world
+ + BL33: a non-trusted firmware = U-Boot, running in normal world and uses
+ the secure monitor to access to secure resources.
+ + HW_CONFIG: The hardware configuration file = the U-Boot device tree
-The **Basic** boot chain
-````````````````````````
+The **Basic** boot chain with SPL
+`````````````````````````````````
-defconfig_file : stm32mp15_basic_defconfig
+defconfig_file :
+ + **stm32mp15_basic_defconfig**
+-------------+------------+------------+-------+
| ROM code | FSBL | SSBL | OS |
| TrustZone | | PSCI from U-Boot |
+-------------+------------+------------+-------+
-SPL has limited security initialization
+SPL has limited security initialization.
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).
for example: use one output directory for each configuration::
+ # export KBUILD_OUTPUT=stm32mp15
# export KBUILD_OUTPUT=stm32mp15_trusted
# export KBUILD_OUTPUT=stm32mp15_basic
you can build outside of code directory::
- # export KBUILD_OUTPUT=../build/stm32mp15_trusted
+ # export KBUILD_OUTPUT=../build/stm32mp15
4. Configure U-Boot::
with <defconfig_file>:
- - For **trusted** boot mode : **stm32mp15_trusted_defconfig**
+ - For **trusted** boot mode : **stm32mp15_defconfig** or
+ stm32mp15_trusted_defconfig
- For basic boot mode: stm32mp15_basic_defconfig
5. Configure the device-tree and build the U-Boot image::
Examples:
- a) trusted boot on ev1::
+ a) trusted boot with FIP on ev1::
- # export KBUILD_OUTPUT=stm32mp15_trusted
- # make stm32mp15_trusted_defconfig
+ # export KBUILD_OUTPUT=stm32mp15
+ # make stm32mp15_defconfig
# make DEVICE_TREE=stm32mp157c-ev1 all
- b) trusted with OP-TEE boot on dk2::
+ b) trusted boot without FIP on dk2::
# export KBUILD_OUTPUT=stm32mp15_trusted
# make stm32mp15_trusted_defconfig
# make stm32mp15_basic_defconfig
# make DEVICE_TREE=stm32mp15xx-dhcor-avenger96 all
-6. Output files
-
- BootRom and TF-A expect binaries with STM32 image header
- SPL expects file with U-Boot uImage header
+6. U-Boot Output files
So in the output directory (selected by KBUILD_OUTPUT),
- you can found the needed files:
+ you can found the needed U-Boot files:
+
+ - stm32mp15_defconfig = **u-boot-nodtb.bin** and **u-boot.dtb**
+
+ - stm32mp15_trusted_defconfig = u-boot.stm32
+
+ - stm32mp15_basic_defconfig
+
+ - FSBL = spl/u-boot-spl.stm32
+
+ - SSBL = u-boot.img (without CONFIG_SPL_LOAD_FIT) or
+ u-boot.itb (with CONFIG_SPL_LOAD_FIT=y)
+
+7. TF-A_ compilation
+
+ This step is required only for **Trusted** boot (stm32mp15_defconfig and
+ stm32mp15_trusted_defconfig); see OP-TEE_ and TF-A_ documentation for build
+ commands.
+
+ - For TF-A_ with FIP support: **stm32mp15_defconfig**
+
+ - with OP-TEE_ support, compile the OP-TEE to generate the binary included
+ in FIP
+
+ - after TF-A compilation, the used files are:
+
+ - TF-A_ BL2 => FSBL = **tf-a.stm32**
+
+ - FIP => **fip.bin**
+
+ FIP file includes the 2 files given in arguments of TF-A_ compilation:
- - For **Trusted** boot (with or without OP-TEE)
+ - BL33=u-boot-nodtb.bin
+ - BL33_CFG=u-boot.dtb
- - FSBL = **tf-a.stm32** (provided by TF-A compilation)
- - SSBL = **u-boot.stm32**
+ You can also update a existing FIP after U-boot compilation with fiptool,
+ a tool provided by TF-A_::
- - For Basic boot
+ # fiptool update --nt-fw u-boot-nodtb.bin --hw-config u-boot.dtb fip-stm32mp157c-ev1.bin
+
+ - For TF-A_ without FIP support : **stm32mp15_trusted_defconfig**
+ SPMin is used and the used files are:
+
+ - FSBL = **tf-a.stm32** (provided by TF-A_ compilation, contening BL2 and
+ BL32 = SPMin)
+
+ - SSBL = **u-boot.stm32** used instead of fip.bin in next chapters
+
+8. The bootloaders files
+
++ The **ROM code** expects FSBL binaries with STM32 image header =
+ tf-a.stm32 or u-boot-spl.stm32
+
+According the FSBL / the boot mode:
+
++ **TF-A** expect a FIP binary = fip.bin, including the OS monitor (SPMin or
+ OP-TEE_) and the U-Boot binary + device tree
+
+ or, without FIP support, binaries with STM32 image header: U-Boot
+ = u-boot.stm32 and eventually OP-TEE files (tee-header.stm32, tee-pageable.stm32,
+ tee-pager.stm32)
+
++ **SPL** expects SSBL = U-Boot with uImage header = u-boot.img
+ or FIT = u-boot.itb.
- - FSBL = spl/u-boot-spl.stm32
- - SSBL = u-boot.img (without CONFIG_SPL_LOAD_FIT) or
- u-boot.itb (with CONFIG_SPL_LOAD_FIT=y)
Switch Setting for Boot Mode
----------------------------
The minimal requirements for STMP32MP15x 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
+- 2 fsbl partitions, named "fsbl1" and "fsbl2", size at least 256KiB
+- one partition named "fip" for FIP or U-Boot (TF-A_ search the "fip"
+ partition and SPL search the 3th partition, because
+ CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION=3)
+
+The 2 fsbl partitions have the same content and are present to guarantee a
+fail-safe update of FSBL; fsbl2 can be omitted if this ROM code feature is
+not required.
+
+Without FIP support in TF-A_, the 3rd partition "fip" for u-boot.stm32 must
+be named "ssbl".
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 |
- +-------+--------+---------+-------------+
- | 4 | <any> | <any> | Rootfs |
- +-------+--------+---------+-------------+
-
-Add a 4th partition (Rootfs) marked bootable with a file extlinux.conf
+For TF-A_ with FIP support:
+
+ +-------+--------+---------+------------------------+
+ | *Num* | *Name* | *Size* | *Content* |
+ +=======+========+=========+========================+
+ | 1 | fsbl1 | 256 KiB | TF-A_ BL2 (tf-a.stm32) |
+ +-------+--------+---------+------------------------+
+ | 2 | fsbl2 | 256 KiB | TF-A_ BL2 (tf-a.stm32) |
+ +-------+--------+---------+------------------------+
+ | 3 | fip | 4MB | fip.bin |
+ +-------+--------+---------+------------------------+
+ | 4 | <any> | <any> | Rootfs |
+ +-------+--------+---------+------------------------+
+
+or:
+
+ +-------+--------+---------+------------------------+------------------------+
+ | *Num* | *Name* | *Size* | *Trusted boot content* | *Basic boot content* |
+ +=======+========+=========+========================+========================+
+ | 1 | fsbl1 | 256 KiB | TF-A_ BL2 (tf-a.stm32) | SPL (u-boot-spl.stm32) |
+ +-------+--------+---------+------------------------+------------------------+
+ | 2 | fsbl2 | 256 KiB | TF-A_ BL2 (tf-a.stm32) | SPL (u-boot-spl.stm32) |
+ +-------+--------+---------+------------------------+------------------------+
+ | 3 | ssbl | 2MB | U-Boot (u-boot.stm32) | U-Boot (u-boot.img) |
+ +-------+--------+---------+------------------------+------------------------+
+ | 4 | <any> | <any> | Rootfs |
+ +-------+--------+---------+------------------------+------------------------+
+
+And the 4th partition (Rootfs) is marked bootable with a file extlinux.conf
following the Generic Distribution feature (doc/README.distro for use).
-According the used card reader select the correct block device
-(for example /dev/sdx or /dev/mmcblk0).
+The size of fip or ssbl partition must be enough for the associated binary file,
+4MB and 2MB are default values.
-In the next example, it is /dev/mmcblk0
+According the used card reader select the correct block device
+(for example /dev/sdx or /dev/mmcblk0), in the next example, it is /dev/mmcblk0
-For example: with gpt table with 128 entries
+For example:
a) remove previous formatting::
# sgdisk -o /dev/<SD card dev>
-b) create minimal image::
+b) create minimal image for FIP
+
+ For FIP support in TF-A_::
# 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 \
- -n 4:5154: -c 4:rootfs \
+ -n 3:1058:9249 -c 3:fip \
+ -n 4:9250: -c 4:rootfs -A 4:set:2 \
-p /dev/<SD card dev>
- With other partition for kernel one partition rootfs for kernel.
+ With gpt table with 128 entries an the partition 4 marked bootable (bit 2).
+
+ For basic boot mode or without FIP support in TF-A_::
+
+ # 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 \
+ -n 4:5154: -c 4:rootfs -A 4:set:2 \
+ -p /dev/<SD card dev>
c) copy the FSBL (2 times) and SSBL file on the correct partition.
in this example in partition 1 to 3
+ for trusted boot: ::
+
+ # dd if=tf-a.stm32 of=/dev/mmcblk0p1
+ # dd if=tf-a.stm32 of=/dev/mmcblk0p2
+ # dd if=fip.bin of=/dev/mmcblk0p3
+ OR
+ dd if=u-boot.stm32 of=/dev/mmcblk0p3 # Without FIT support
+
for basic boot mode : <SD card dev> = /dev/mmcblk0::
# dd if=u-boot-spl.stm32 of=/dev/mmcblk0p1
OR
dd if=u-boot.itb of=/dev/mmcblk0p3 # With CONFIG_SPL_LOAD_FIT=y
- 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 SD card, select BootPinMode = 1 0 1 and reset.
Prepare eMMC
You can use U-Boot to copy binary in eMMC.
In the next example, you need to boot from SD card and the images
-(u-boot-spl.stm32, u-boot.img for systems without CONFIG_SPL_LOAD_FIT
-or u-boot.itb for systems with CONFIG_SPL_LOAD_FIT=y) are presents on
-SD card (mmc 0) in ext4 partition 4 (bootfs).
+(tf-a.stm32, fip.bin / u-boot-spl.stm32, u-boot.img for systems without
+CONFIG_SPL_LOAD_FIT or u-boot.itb for systems with CONFIG_SPL_LOAD_FIT=y) are
+presents on SD card (mmc 0) in ext4 partition 4 (bootfs)
To boot from SD card, 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::
+ example with 3 partitions, fip, bootfs and roots::
- # setenv emmc_part "name=ssbl,size=2MiB;name=bootfs,type=linux,bootable,size=64MiB;name=rootfs,type=linux,size=512"
+ # setenv emmc_part "name=fip,size=4MiB;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
+b) copy FSBL, TF-A_ or SPL, on first eMMC boot partition
(SPL max size is 256kB, with LBA 512, 0x200)::
+ # ext4load mmc 0:4 0xC0000000 tf-a.stm32
+ or
# 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::
+c) copy SSBL, FIP or U-Boot binary, in first GPT partition of eMMC::
+ # ext4load mmc 0:4 0xC0000000 fip.bin
+ or
# ext4load mmc 0:4 0xC0000000 u-boot.img # Without CONFIG_SPL_LOAD_FIT
- OR
- ext4load mmc 0:4 0xC0000000 u-boot.itb # With CONFIG_SPL_LOAD_FIT=y
+ or
+ # ext4load mmc 0:4 0xC0000000 u-boot.itb # With CONFIG_SPL_LOAD_FIT=y
+
+
# mmc dev 1
# part start mmc 1 1 partstart
# mmc write ${fileaddr} ${partstart} ${filesize}
see examples in the board stm32mp1 directory: fit_copro_kernel_dtb.its
- Generate FIT including kernel + device tree + M4 firmware with cfg with M4 boot::
+ Generate FIT including kernel + device tree + M4 firmware with cfg with M4
+ boot::
$> mkimage -f fit_copro_kernel_dtb.its fit_copro_kernel_dtb.itb
STM32MP> dfu 0
-On EV1 board, booting from SD card, without OP-TEE::
+On EV1 board, booting from SD card, without OP-TEE_::
STM32MP> dfu 0 list
DFU alt settings list:
dev: RAM alt: 2 name: uramdisk.image.gz layout: RAM_ADDR
dev: eMMC alt: 3 name: mmc0_fsbl1 layout: RAW_ADDR
dev: eMMC alt: 4 name: mmc0_fsbl2 layout: RAW_ADDR
- dev: eMMC alt: 5 name: mmc0_ssbl layout: RAW_ADDR
+ dev: eMMC alt: 5 name: mmc0_fip layout: RAW_ADDR
dev: eMMC alt: 6 name: mmc0_bootfs layout: RAW_ADDR
dev: eMMC alt: 7 name: mmc0_vendorfs layout: RAW_ADDR
dev: eMMC alt: 8 name: mmc0_rootfs layout: RAW_ADDR
dev: eMMC alt: 9 name: mmc0_userfs layout: RAW_ADDR
dev: eMMC alt: 10 name: mmc1_boot1 layout: RAW_ADDR
dev: eMMC alt: 11 name: mmc1_boot2 layout: RAW_ADDR
- dev: eMMC alt: 12 name: mmc1_ssbl layout: RAW_ADDR
+ dev: eMMC alt: 12 name: mmc1_fip layout: RAW_ADDR
dev: eMMC alt: 13 name: mmc1_bootfs layout: RAW_ADDR
dev: eMMC alt: 14 name: mmc1_vendorfs layout: RAW_ADDR
dev: eMMC alt: 15 name: mmc1_rootfs layout: RAW_ADDR
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=15, name="mmc1_rootfs", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=14, name="mmc1_vendorfs", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=13, name="mmc1_bootfs", serial="002700333338511934383330"
- Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=12, name="mmc1_ssbl", serial="002700333338511934383330"
+ Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=12, name="mmc1_fip", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=11, name="mmc1_boot2", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=10, name="mmc1_boot1", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=9, name="mmc0_userfs", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=8, name="mmc0_rootfs", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=7, name="mmc0_vendorfs", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=6, name="mmc0_bootfs", serial="002700333338511934383330"
- Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=5, name="mmc0_ssbl", serial="002700333338511934383330"
+ Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=5, name="mmc0_fip", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=4, name="mmc0_fsbl2", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=3, name="mmc0_fsbl1", serial="002700333338511934383330"
Found DFU: [0483:df11] ver=9999, devnum=99, cfg=1, intf=0, alt=2, name="uramdisk.image.gz", serial="002700333338511934383330"
- SD card (mmc0) ::
- $> dfu-util -d 0483:5720 -a 3 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 4 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 5 -D u-boot-stm32mp157c-ev1-trusted.img
+ $> dfu-util -d 0483:5720 -a 3 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 4 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 5 -D fip-stm32mp157c-ev1.bin
$> dfu-util -d 0483:5720 -a 6 -D st-image-bootfs-openstlinux-weston-stm32mp1.ext4
$> dfu-util -d 0483:5720 -a 7 -D st-image-vendorfs-openstlinux-weston-stm32mp1.ext4
$> dfu-util -d 0483:5720 -a 8 -D st-image-weston-openstlinux-weston-stm32mp1.ext4
- EMMC (mmc1)::
- $> dfu-util -d 0483:5720 -a 10 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 11 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 12 -D u-boot-stm32mp157c-ev1-trusted.img
+ $> dfu-util -d 0483:5720 -a 10 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 11 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 12 -D fip-stm32mp157c-ev1.bin
$> dfu-util -d 0483:5720 -a 13 -D st-image-bootfs-openstlinux-weston-stm32mp1.ext4
$> dfu-util -d 0483:5720 -a 14 -D st-image-vendorfs-openstlinux-weston-stm32mp1.ext4
$> dfu-util -d 0483:5720 -a 15 -D st-image-weston-openstlinux-weston-stm32mp1.ext4
- NOR (nor0 = alt 20) & NAND (nand0 = alt 26) ::
- $> dfu-util -d 0483:5720 -a 21 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 22 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 23 -D u-boot-stm32mp157c-ev1-trusted.img
+ $> dfu-util -d 0483:5720 -a 21 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 22 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 23 -D fip-stm32mp157c-ev1.bin
$> dfu-util -d 0483:5720 -a 27 -D st-image-weston-openstlinux-weston-stm32mp1_nand_4_256_multivolume.ubi
- NAND (nand0 = alt 21)::
- $> dfu-util -d 0483:5720 -a 22 -D tf-a-stm32mp157c-ev1-trusted.stm32
- $> dfu-util -d 0483:5720 -a 23 -D u-boot-stm32mp157c-ev1-trusted.img
- $> dfu-util -d 0483:5720 -a 24 -D u-boot-stm32mp157c-ev1-trusted.img
+ $> dfu-util -d 0483:5720 -a 22 -D tf-a-stm32mp157c-ev1.stm32
+ $> dfu-util -d 0483:5720 -a 23 -D fip-stm32mp157c-ev1.bin
+ $> dfu-util -d 0483:5720 -a 24 -D fip-stm32mp157c-ev1.bin
$> dfu-util -d 0483:5720 -a 25 -D st-image-weston-openstlinux-weston-stm32mp1_nand_4_256_multivolume.ubi
+
+References
+----------
+
+.. _WIKI:
+
+STM32 Arm® Cortex®-based MPUs user guide
+
+ + https://wiki.st.com/
+ + https://wiki.st.com/stm32mpu/wiki/Main_Page
+
+.. _TF-A:
+
+TF-A = The Trusted Firmware-A project provides a reference implementation of
+secure world software for Armv7-A and Armv8-A class processors
+
+ + https://www.trustedfirmware.org/projects/tf-a/
+ + https://trustedfirmware-a.readthedocs.io/en/latest/
+ + https://trustedfirmware-a.readthedocs.io/en/latest/plat/stm32mp1.html
+ + https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/
+
+.. _OP-TEE:
+
+OP-TEE = an open source Trusted Execution Environment (TEE) implementing the
+Arm TrustZone technology
+
+ + https://www.op-tee.org/
+ + https://optee.readthedocs.io/en/latest/
+ + https://optee.readthedocs.io/en/latest/building/devices/stm32mp1.html
+ + https://github.com/OP-TEE/optee_os
\ No newline at end of file