1. Introduction to external device tree component[edit source]
The external device tree component is used to host STM32 MPU embedded software device tree configurations in addition of the ones present in each software component (TF-A, OP-TEE, U-BOOT, LINUX, TF-M).
The external device tree repository can be found here .
Please, find below some kind of configurations stored in this repository:
- Linux RT for STM32MP1xx and STM32MP2xx series.
- STM32MP2xx CA35TDCID ecosystem (aka ostl device tree) in addition of the minimal configuration present in each software component.
- STM32CubeMP2 M33 examples (aka ostl-m33-examples device tree)
- ... other configurations to come soon... (STM32MP2xx CM33TDCID ecosystem, ...)
As configurations become increasingly complex, it is important to synchronize all software components device trees in one place. This centralization permits to have a coherent configuration across all of them.
This consistent product configuration is given as example by ST in this external device tree repository and is used by YOCTO build system.
2. Component usage[edit source]
It can directly be used by OSTL Yocto build system or directly by each software component. Let see how to use it:
- TF-A: External device tree in TF-A
- OP-TEE: External device tree in OP-TEE
- U-Boot: External device tree in U-Boot
- Linux: External device tree in kernel Linux
- TFM: External device tree in TF-M
3. STM32MP2xx ecosystem device tree details[edit source]
The firewall configuration (RIF) has been introduced in STM32MP2xx series and it involves a coherence and synchronization between these system configuration files (rcc, rif and resmem).
The device tree files, related to the "SoC" definition, are located as described below:
- RIF (firewall) configuration in OP-TEE: stm32mp257f-ev1-ca35tdcid-ostl-rif.dtsi
- RCC (Clock tree) configuration in TF-A and OP-TEE: stm32mp257f-ev1-ca35tdcid-ostl-rcc.dtsi
- Memory mapping configuration an all components: stm32mp257f-ev1-ca35tdcid-ostl-resmem.dtsi
- Board configuration in all components: stm32mp257f-ev1-ca35tdcid-ostl.dts
DT name example given for an EV1 ("ev1") board with Cortex-A35 ("ca35") set as main processor for STM32MP25xF lines 
(stm32mp257f).
4. References[edit source]
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere. 