Re: [PATCH] mmc: meson-mx-sdio: trigger a soft reset after a timeout or CRC error

[Ulf Hansson <ulf.hansson@linaro.org>]

On Mon, 4 May 2020 at 00:28, Martin Blumenstingl
<martin.blumenstingl@googlemail.com> wrote:
>
> The vendor driver (from the 3.10 kernel) triggers a soft reset every
> time before starting a new command. While this fixes a problem where
> SDIO cards are not detected at all (because all commands simply
> timed out) this hurts SD card read performance a bit (in my tests
> between 10% to 20%).
>
> Trigger a soft reset after we got a CRC error or if the previous command
> timed out (just like the vendor driver from the same 3.10 kernel for the
> newer SDHC controller IP does). This fixes detection of SDIO cards and
> doesn't hurt SD card read performance at the same time.
>
> With this patch the initialization of an RTL8723BS SDIO card looks like
> this:
>   req done (CMD52): -110: 00000000 00000000 00000000 00000000
>   clock 400000Hz busmode 2 powermode 2 cs 1 Vdd 21 width 1 timing 0
>   starting CMD0 arg 00000000 flags 000000c0
>   req done (CMD0): 0: 00000000 00000000 00000000 00000000
>   clock 400000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 1 timing 0
>   starting CMD8 arg 000001aa flags 000002f5
>   req done (CMD8): -110: 00000000 00000000 00000000 00000000
>   starting CMD5 arg 00000000 flags 000002e1
>   req done (CMD5): 0: 90ff0000 00000000 00000000 00000000
>   starting CMD5 arg 00200000 flags 000002e1
>   req done (CMD5): 0: 90ff0000 00000000 00000000 00000000
>   starting CMD3 arg 00000000 flags 00000075
>   req done (CMD3): 0: 00010000 00000000 00000000 00000000
>   starting CMD7 arg 00010000 flags 00000015
>   req done (CMD7): 0: 00001e00 00000000 00000000 00000000
>   starting CMD52 arg 00000000 flags 00000195
>   req done (CMD52): 0: 00001032 00000000 00000000 00000000
>   [... more CMD52 omitted ...]
>   clock 400000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 1 timing 2
>   clock 50000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 1 timing 2
>   starting CMD52 arg 00000e00 flags 00000195
>   req done (CMD52): 0: 00001000 00000000 00000000 00000000
>   starting CMD52 arg 80000e02 flags 00000195
>   req done (CMD52): 0: 00001002 00000000 00000000 00000000
>   clock 50000000Hz busmode 2 powermode 2 cs 0 Vdd 21 width 4 timing 2
>   starting CMD52 arg 00020000 flags 00000195
>   req done (CMD52): 0: 00001007 00000000 00000000 00000000
>   [... more CMD52 omitted ...]
>   new high speed SDIO card at address 0001
>
> Fixes: ed80a13bb4c4c9 ("mmc: meson-mx-sdio: Add a driver for the Amlogic Meson8 and Meson8b SoCs")
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> ---
> Ulf, I consider this non-critical because as long as the meson-mx-sdhc
> driver is not merged we only have one MMC driver for these platforms.
> I don't know anybody to prefer SDIO wifi over SD card access, so this
> can go into -next (in my option at least).
>

Alright, applied for next, thanks!

Kind regards
Uffe


>
>  drivers/mmc/host/meson-mx-sdio.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/mmc/host/meson-mx-sdio.c b/drivers/mmc/host/meson-mx-sdio.c
> index 2e58743d83bb..3813b544f571 100644
> --- a/drivers/mmc/host/meson-mx-sdio.c
> +++ b/drivers/mmc/host/meson-mx-sdio.c
> @@ -246,6 +246,9 @@ static void meson_mx_mmc_request_done(struct meson_mx_mmc_host *host)
>
>         mrq = host->mrq;
>
> +       if (host->cmd->error)
> +               meson_mx_mmc_soft_reset(host);
> +
>         host->mrq = NULL;
>         host->cmd = NULL;
>
> --
> 2.26.2
>