Re: [PATCH] arm64: dts: rockchip: Assign a fixed index to mmc devices on rk3399-roc-pc boards.

[Markus Reichl]

Hi Heiko,

Am 04.11.20 um 11:51 schrieb Heiko Stübner:
> Hi Markus,
>
> Am Mittwoch, 4. November 2020, 10:49:45 CET schrieb Markus Reichl:
> > Recently introduced async probe on mmc devices can shuffle block IDs.
> > Pin them to fixed values to ease booting in evironments where UUIDs
> > are not practical. Use newly introduced aliases for mmcblk devices from [1].
> >
> > [1]
> > https://patchwork.kernel.org/patch/11747669/
> >
> > Signed-off-by: Markus Reichl <m.reichl@xxxxxxxxxxxxx>
> > ---
> >  arch/arm64/boot/dts/rockchip/rk3399-roc-pc.dtsi | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3399-roc-pc.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-roc-pc.dtsi
> > index e7a459fa4322..bc9482b59428 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3399-roc-pc.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3399-roc-pc.dtsi
> > @@ -13,6 +13,11 @@ / {
> >  	model = "Firefly ROC-RK3399-PC Board";
> >  	compatible = "firefly,roc-rk3399-pc", "rockchip,rk3399";
> >  
> > +	aliases {
> > +		mmc0 = &sdmmc;
> > +		mmc1 = &sdhci;
> > +	};
> > +
>
> Any reason for this odering?

Without pinning roc-pc mostly booted as
mmcblk0 = sdmmc = µSD
mmcblk1 = sdhci = eMMC
so I kept this behaviour in aliases

roc-pc-mezzanine with populated SDIO-M2-slot booted
mmc0 = sdio = (no mmcblk)
mmcblk1 = sdmmc = µSD
mmcblk2 = sdhci = eMMC

With my aliases both boards behave the same now and the optional SDIO slot
goes out of the way to mmc2.

> I.e. some previous incarnations had it ordered as (emmc, mmc, sdio).
> This is also true for the ChromeOS out-of-tree usage of those, the
> rk3399 dts in the chromeos-4.4 tree also orders this as sdhci, sdmmc, sdio.

The boards from my zoo (exynos, rk3399) mostly come up with SD-card as mmc0
and eMMC as mmc1 in mainline as opposed in some vendor kernels.
but I have no objection to set it the other way round if this is more common
with rk3399 boards.

> And I guess a further question would be when we're doing arbitary orderings
> anyway, why is this not in rk3399.dtsi ;-) ?

I restricted the ordering to the boards I have, not to confuse other established
use cases, but if a standard ordering is desired this can go to rk3399.dtsi.

> Heiko

Gruß,
--
Markus Reichl