Hi Shimoda-san,
On Mon, Mar 1, 2021 at 12:06 PM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> After the commit 7320915c8861 ("mmc: Set PROBE_PREFER_ASYNCHRONOUS
> for drivers that existed in v4.14"), the order of /dev/mmcblkN
> was not fixed in some SoCs which have multiple sdhi controllers.
> So, we were hard to use an sdhi device as rootfs by using
> the kernel parameter like "root=/dev/mmcblkNpM".
>
> According to the discussion on a mainling list [1], we can add
> mmc aliases to fix the issue. So, add such aliases into Renesas
> arm64 board dts files. Notes that mmc0 is an eMMC channel if
> available.
>
> [1]
> https://lore.kernel.org/linux-arm-kernel/CAPDyKFptyEQNJu8cqzMt2WRFZcwEdjDiytMBp96nkoZyprTgmA@xxxxxxxxxxxxxx/
>
> Fixes: 7320915c8861 ("mmc: Set PROBE_PREFER_ASYNCHRONOUS for drivers that existed in v4.14")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
i.e. will queue in renesas-devel for v5.13.
> --- a/arch/arm64/boot/dts/renesas/r8a774a1-beacon-rzg2m-kit.dts
> +++ b/arch/arm64/boot/dts/renesas/r8a774a1-beacon-rzg2m-kit.dts
> @@ -21,6 +21,9 @@
> serial4 = &hscif2;
> serial5 = &scif5;
> ethernet0 = &avb;
> + mmc0 = &sdhi3;
> + mmc1 = &sdhi0;
> + mmc2 = &sdhi2;
The last one is used to host a fixed SDIO device (the same is true for the
other beacon boards, and for cat874). As there is no need for the user
to refer to this mmc bus, I don't think it's strictly necessary to have an alias
for it. But it's nice to have, for consistency.
> --- a/arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts
> +++ b/arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts
> @@ -17,6 +17,8 @@
> aliases {
> serial0 = &scif2;
> serial1 = &hscif2;
> + mmc0 = &sdhi0;
> + mmc1 = &sdhi3;
> };
Note that on cat874, unused sdhi1 is wired to an expansion connector.
If we ever see an expansion board adding an SD slot to SDHI, we can
change the aliases to make mmc1 point to sdhi1. The SDIO device
won't care.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
