How to configure SDMMC Pin in STMCubeMx to make Board contain two SDMMC partitions both used for boot ?

[FHami.1]

Hello everyone,

I'm configuring my STM32MP157C-DK2 Board pins and i want to make two SD Card partitions availabe.

For the first one i chose the SDMMC1 and attributed it to PC10 pin

for the second one do i need to choose SDMMC2 and to attribute it to another pin (for ex. PC6) or is it wrong ?

Or can i divide later in the device tree ?

[PatrickF]

Hi,

please note that on DK2 board, SDMMC2 is used for WLAN.

You could have both SDMMC1 and SDMMC2 used for two SD-Cards if you build your own specific board, but it is not possible to assign the two as boot (the second card will be seen as an additional filesystem which might contain data or even kernel).

SD-Card boot could be either SDMMC1 on default pins or SDMMC2 when defined by OTP (not reversible). This is a fixed choice.

In OTP, you could define a primary and a secondary boot source, but both should be on a different kind of memory (e.g. Serial-NOR + SD-Card). i.e. SD-Card +SD-Card on two different interface is not possible.

See https://wiki.st.com/stm32mpu/wiki/STM32MP15_ROM_code_overview#Configuration

Regards.

[FHami.1]

Hello @PatrickF​ ,

Thanks for the reply.

The problem is, i want to use rauc updater in my st-image-weston linux image on the STM32MP157C-DK2  to deliver easy and fast updates. rauc is an update tool that can be configured in yocto. rauc uses two partitions. It boots from the first one and installs the update on the second one and then boots from the second one (and vice versa in the next updates). That's why i want to devide the sdcard of the dk2 board into two partitions (on the same sdcard). That way the linux image will be only installed on one of the two partitions. since it's not possible to configure it in the configuration, is it possible to do it in the device tree ? or it should be done inside yocto ?