Purpose of board ID field in OTP

[stefankempf]

Hello,

U-Boot has an stboard command that writes a board ID into OTP (word 59 on STM32MP15x lines, word 60 on 13x lines).

TF-A displays this board ID if a device tree label "board_id" is present in the bsec node.

Could you please explain the purpose of the board ID field and how it should be used when developing a custom product/board with a STM32MP1 CPU? Is it intended that we give our products a board ID in the structure as evaluated/printed in the TF-A code?

Or is this just a field for ST eval boards and irrelevant for custom product developments?

Thanks.

[PatrickF · Accepted solution]

Hi @stefankempf 

This is pure ST custom to allows to support more than one board with a single SW (e.g. automated device tree choice for uBoot/Linux or during board production tests).

Although I'm not sure it is used like this. At least it allows to print the board name during ST starter package boot.

On your own development, the related OTP could be used for other purposes.

Regards.

[stefankempf]

Thank you, that clear it up for me.