[U-Boot] [PATCH] env_mmc: support overriding mmc dev from board code

[Stephen Warren]

On 01/20/2016 07:43 AM, Clemens Gruber wrote:
> This enables boards to choose where to/from the environment should be
> saved/loaded. They can then for example support using the same device
> (dynamically) from which the bootloader was launched to load and save
> env data and do not have to define CONFIG_SYS_MMC_ENV_DEV statically.
>
> In my use case, the environment needs to be on the same device I
> booted from. It can be the eMMC or an optional SD card.
> I therefore would override mmc_get_env_dev in the board code, read the
> CPU registers to determine where we booted from and return the
> corresponding device index.

Reviewed-by: Stephen Warren <swarren at nvidia.com>

I was going to ask: What about the HW partition number and offset, but 
it appears that there is already a method to override those at run-time:-)