[PATCH] sunxi: Bring back SD card as MMC device 0

Jagan Teki jagan at amarulasolutions.com
Sun Apr 25 14:33:05 CEST 2021

On Sun, Apr 25, 2021 at 3:30 PM Andre Przywara <andre.przywara at arm.com> wrote:
> On Fri, 16 Apr 2021 12:08:09 +0100
> Andre Przywara <andre.przywara at arm.com> wrote:
> Hi,
> > Commit 2243d19e5618 ("mmc: mmc-uclass: Use dev_seq() to read aliases
> > node's index") now actually enforces U-Boot's device enumeration policy,
> > where explicitly named devices come first, then any other non-named
> > devices follow, without filling gaps.
> >
> > For quite a while we have had an "mmc1 = &mmc2;" alias in our
> > sunxi-u-boot.dtsi, which now leads to the problem that the SD card
> > (which was always mmc device 0) now gets to be number 2.
> > I guess this breaks quite some boot scripts, and is confusing at least.
> >
> > Just add an explicit mmc0 alias in the very same file to fix this and
> > restore the old behaviour.
> Can someone please say if this is the right solution?
> I think the SD card has always been mmc device 0 in U-Boot, so I think
> it's worth keeping that. Just not sure if this is the right way of
> fixing that?

Playing with aliases always gets confused and might get a different
behavior, IMHO. Detect the dev number by U-Boot itself and look at
traverse bootenv by all possible dev numbers in sunxi-common.h, but
this has one slide effect that we mark mmc2 as devnum 1 for the sake
of fastboot so if we mark fastboot number for specific board properly
(by static or runtime) then explicit aliases wouldn't required.


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