How to be able to use the A7 cores without Linux (on a STM32MP157) ?

[Mohammed-Ismail Ben Salah]

Hello everyone,

I'm using an STM32MP157-DK1 and i'm really interested in doing bare-metal/RTOS usage of this new microprocessor. Unfortunately at the moment the documentation is more focused on how to deploy Linux and use the A7 cores with Linux.

My guess would be to see how to be able to use the ROM code to be able to load a custom first stage bootloader to charge my code and access the peripherals. For this purpose i would try to generate a custom partition on a SD Card with the needed code. Could i have any input about this kind of usage ?

I'm currently looking on the Developer & Distribution package in order to understand how is generated the different partition and how is generated the FSBL. Could i have any precision about the generation of the FSBL ?

Last question but not the least : I'm looking for the AN5275 STM32MP1 Series: USB DFU/USART protocols used in bootloader application note. Is there any way to obtain it ?

Best Regards and thanks in advance for your answers,

Ismail Ben Salah

[Olivier GALLIEN]

Hi @Mohammed-Ismail Ben Salah​ 

AN5275 STM32MP1 Series: USB DFU/USART protocols used in bootloader application note is planned to be deliver by October this year.

Keep you posted here when done.

Olivier

[李林.1312]

I hard wish to use STM32MP157 without Linux too, just bare-metal. if ST have some related resource, please tell me, thanks!

[e-mail]

[snigg]

This thread is 9 month old yet I do not see a definitive answer nor can I find information from ST. Is there official information on bare metal programming a STM32MP or is there any other project that uses the raw power of these cores directly? I am interested in the chip but do not want to waste anything on linux at all.

[Mohammed-Ismail Ben Salah]

We managed at CSEM to use it in bare-metal without any Linux. However it needed a huge reverse engineering effort to be able to proceed so.

The steps are the following :

1. Create you own linker script using part of the SYSRAM (the wiki should give you infos about which zone is usable (there's a small zone of SYSRAM used by BootROM)

2. Also you need to be able to have a toolchain to generate a binary file to will comply with the stm32header (and be recognized by bootROM)

2b. Of course you also need to configure the toolchain to generate code that will have the correct compilation flag and also understand in which mode the first CPU boot.

There was in the linux distribution package an modified openOCD version to is able to communicate with the MP1 processor.

https://wiki.st.com/stm32mpu/wiki/STM32MP15_ROM_code_overview

We should see if ST is interested to provide a minimal guide to enable baremetal programming.

Best Regard,

Mohammed Ismail Ben Salah

[Genadi Zawidowski]

Just for information: I am use own six-layer board as CPU module for drive software defined radio project.

QSPI FLASH memory, VTT supply, 12V -> 1.2V and 12V->1.35V on board. And RESET monitor,