[U-Boot] [PATCH v3 27/58] fastboot: sunxi: Update fastboot mmc default device

[Maxime Ripard]

On Mon, Aug 27, 2018 at 02:50:32PM +0530, Jagan Teki wrote:
> On Wed, Aug 22, 2018 at 10:13 PM, Maxime Ripard
> <maxime.ripard at bootlin.com> wrote:
> > On Tue, Aug 21, 2018 at 10:27:38PM +0530, Jagan Teki wrote:
> >> On Mon, Aug 20, 2018 at 5:14 PM, Maxime Ripard
> >> <maxime.ripard at bootlin.com> wrote:
> >> > On Sun, Aug 19, 2018 at 07:26:44PM +0530, Jagan Teki wrote:
> >> >> Usually eMMC is default mmc device for fastboot.
> >> >>
> >> >> By enabling DM_MMC, the mmc devices are probed as per
> >> >> DT status not with respect to MMC_SUNXI_SLOT_EXTRA in
> >> >> U-Boot proper.
> >> >>
> >> >> Allwinner SoC has maximum of 4 mmc controllers start from
> >> >> mmc0...mmc3 on which mmc2 can be used an eMMC controller
> >> >> eventhough mmc3 some boards used as eMMC.
> >> >>
> >> >> So, update the default fastboot device as 2 to make the
> >> >> standard usage irrespective of DT node status.
> >> >>
> >> >> Other corner cases like different device usage, or specific
> >> >> mmc node status is not enabled in order in DTS must explicitly
> >> >> add config on the specific defconfig file.
> >> >>
> >> >> Cc: Olliver Schinagl <oliver at schinagl.nl>
> >> >> Cc: Chen-Yu Tsai <wens at csie.org>
> >> >> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> >> >
> >> > This breaks all existing users, since if DM_MMC isn't set (and it
> >> > isn't at the moment), the MMC IDs won't change, and you're changing it
> >> > from either 0 or 1 to 2.
> >>
> >> True, bisectable issue. will take care on next version.
> >>
> >> >
> >> > Can't we have a DT property instead? It looks much better than having
> >> > to deal with a non stable ID in Kconfig.
> >>
> >> What do you mean by DT property handle? mmc2 is eMMC in all sunXi
> >> isn't? ie reason I make it default.
> >
> > I meant to select the fastboot and environment devices. That way, each
> > board can select the one it wants in a truly deterministic way.
> 
> ie what get_env_fat_dev_part is doing. Identify the dev no.of
> initialized mmc or emmc. are you referring something like this?

Yep, but through a DT property instead of some code.

Maxime

-- 
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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