How can we boot from emmc on SDMMC1 interface?

[stack_shailesh]

We have set SDMMC1 pin muxing like below. How can we boot from emmc on SDMMC1 interface??? Where should I do partitioning for emmc??

Kindly give solution-

D14	PC8	SDMMC1_D0
A16	PC9	SDMMC1_D1
B14	PC10	SDMMC1_D2
C14	PC11	SDMMC1_D3
A13	PB14	SDMMC1_D4
D9	PB12	SDMMC1_D5
B11	PC6	SDMMC1_D6
A11	PC7	SDMMC1_D7
A15	PD2	SDMMC1_CMD
B15	PC12	SDMMC1_CK

[TDK]

Booting from eMMC doesn't make sense in this context. The MCU doesn't run an operating system that need to load various files, like a computer does.

Edit: I now see this was posted in the "STM32 MPUs" forum, yet with a tag of "STM32Cube MCU Packages," hence my answer. I suspect it's meant to be an MPU-specific question but who knows. No chip specified.

[PatrickF · Accepted solution]

Hi @stack_shailesh 

As eMMC default is SDMMC2, you should tell the BootROM to use SDMMC1 and related pins (only CLK, CMD and D0 is needed for BootROM stage, then pinmux is defined by Device Tree). To do this, you should program the OTP.

https://wiki.st.com/stm32mpu/wiki/How_to_update_OTP_with_U-Boot

https://wiki.st.com/stm32mpu/wiki/STM32CubeProgrammer_OTP_management

Assuming you are using STM32MP15, this post might help you to understand values you should put according to your HW.

https://community.st.com/t5/stm32-mpus-products/how-to-change-emmc-interface/td-p/344994

See also AN5031 (for STM32MP15) or AN5474 (STM32MP13)

wiki give some information too:

https://wiki.st.com/stm32mpu/wiki/STM32_MPU_ROM_code_overview#Boot_from_e-E2-80-A2MMC-E2-84-A2

https://wiki.st.com/stm32mpu/wiki/STM32MP15_OTP_mapping#AFmux_configuration or https://wiki.st.com/stm32mpu/wiki/STM32MP13_OTP_mapping#AFmux_configuration

Regards.

[stack_shailesh]

Thanks Patrick, after following steps and changing my AFmux config I am able to boot from emmc.