Linux-console on UART for STM32MP25 / STLinux

[HMüll.4]

Hi,

for evaluation I'm running STLinux on a STM32MP257F-DK board currently.

I found the Linux console is available on one of the USB-ports with the default configuration of that operating system.

Quick question: is that Linux console also available on some plain UART-port for that development kit (or for the STM32MP25 in general)? If yes: which port is used?

Thanks!

[GatienC]

Hi,

What exactly is "plain UART port"?

You can change which UART you wish to use in the board device tree file of the Linux kernel I guess (serial aliases). That stated, you can check the board schematics to know what is available on the GPIO expansion connector for the STM32MP257F-DK. I already checked and saw that USART6 is available on it :) (TX pin8 and RX pin10) so feel free to use them!

I hope this helps,

Gatien

[GatienC]

Please have a look at https://community.st.com/t5/stm32-mpus-embedded-software-and/stm32mp257-usart-and-serc-exception/td-p/794150 as well

[HMüll.4]

Hello Gatien,

thank you for your answer. That device-tree-stuff is known to me, but I wonder if there is already a port defined in standard STMLinux. So when running that STMLinux stuff on the STM32MP257F-DK-board, both without any changes, everythign used as it is shipped, do I find that Linux console output on any UART?

Thanks!

[GatienC · Accepted solution]

Hello!

Looking at the arch/arm64/boot/dts/st/stm32mp257f-dk.dts file, the USART3 is not enabled, therefore it's default disabled for this board. Enabling the node in the board device tree and handling the M33 firmware as mentioned in the linked post above may be sufficient.

Regards,

Gatien