[U-Boot] sunxi board: why MMC dev are swapped ?

[Mylene Josserand]

Hi everyone,


I am currently using FEL and Fastboot to flash a sunxi-device with SPL 
and u-boot.


In my board, I have two MMC devices: a MMC slot and an eMMC.

My use-case is to flash an empty device. I want to use FEL to boot a 
u-boot and then, use fastboot to flash u-boot into eMMC.

When I am using an u-boot via FEL, the eMMC is configured as MMC1. To be 
able to flash u-boot on it, I need to set CONFIG_FASTBOOT_FLASH_MMC_DEV 
to 1. Thanks to that, the flashboot command is working fine.
But when I am booting on my fresh u-boot from eMMC, it is now configured 
as MMC0 and not MMC1 anymore.

It produces some problems in my case as I configured the 
CONFIG_FASTBOOT_FLASH_MMC_DEV to 1 so I can not use fastboot anymore to 
flash the eMMC (as, now, fastboot is trying to flash u-boot on my MMC 
slot and not my eMMC). This is clearly not what I wanted to. I would 
like to use fastboot to flash the same MMC device: eMMC.

This issue is located in this part of the code:
http://git.denx.de/?p=u-boot.git;a=blob;f=board/sunxi/board.c;h=53656383d512199338dcdc1d4fdc4f7f939c9b61;hb=HEAD#l377

Do you know why sunxi boards have this behavior ? Why this MMC device's 
swap is implemented ?

Thank you in advance for your help,

Best regards,

-- 
Mylène Josserand, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com