Re: [PATCH v2] MMC: OMAP: fix broken MMC on OMAP15XX/OMAP5910/OMAP310

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

On Tue, 20 Nov 2018 at 00:14, Aaro Koskinen <aaro.koskinen@iki.fi> wrote:
>
> Since v2.6.22 or so there has been reports [1] about OMAP MMC being
> broken on OMAP15XX based hardware (OMAP5910 and OMAP310). The breakage
> seems to have been caused by commit 46a6730e3ff9 ("mmc-omap: Fix
> omap to use MMC_POWER_ON") that changed clock enabling to be done
> on MMC_POWER_ON. This can happen multiple times in a row, and on 15XX
> the hardware doesn't seem to like it and the MMC just stops responding.
> Fix by memorizing the power mode and do the init only when necessary.
>
> Before the patch (on Palm TE):
>
>         mmc0: new SD card at address b368
>         mmcblk0: mmc0:b368 SDC   977 MiB
>         mmci-omap mmci-omap.0: command timeout (CMD18)
>         mmci-omap mmci-omap.0: command timeout (CMD13)
>         mmci-omap mmci-omap.0: command timeout (CMD13)
>         mmci-omap mmci-omap.0: command timeout (CMD12) [x 6]
>         mmci-omap mmci-omap.0: command timeout (CMD13) [x 6]
>         mmcblk0: error -110 requesting status
>         mmci-omap mmci-omap.0: command timeout (CMD8)
>         mmci-omap mmci-omap.0: command timeout (CMD18)
>         mmci-omap mmci-omap.0: command timeout (CMD13)
>         mmci-omap mmci-omap.0: command timeout (CMD13)
>         mmci-omap mmci-omap.0: command timeout (CMD12) [x 6]
>         mmci-omap mmci-omap.0: command timeout (CMD13) [x 6]
>         mmcblk0: error -110 requesting status
>         mmcblk0: recovery failed!
>         print_req_error: I/O error, dev mmcblk0, sector 0
>         Buffer I/O error on dev mmcblk0, logical block 0, async page read
>          mmcblk0: unable to read partition table
>
> After the patch:
>
>         mmc0: new SD card at address b368
>         mmcblk0: mmc0:b368 SDC   977 MiB
>          mmcblk0: p1
>
> The patch is based on a fix and analysis done by Ladislav Michl.
>
> Tested on OMAP15XX/OMAP310 (Palm TE), OMAP1710 (Nokia 770)
> and OMAP2420 (Nokia N810).
>
> [1] https://marc.info/?t=123175197000003&r=1&w=2
>
> Fixes: 46a6730e3ff9 ("mmc-omap: Fix omap to use MMC_POWER_ON")
> Reported-by: Ladislav Michl <ladis@linux-mips.org>
> Reported-by: Andrzej Zaborowski <balrogg@gmail.com>
> Tested-by: Ladislav Michl <ladis@linux-mips.org>
> Acked-by: Tony Lindgren <tony@atomide.com>
> Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe

> ---
>
>         v2: Corrected commit message: OMAP5912 => OMAP5910
>             Added Tested-by and Acked-by tags.
>
>         v1: https://marc.info/?t=154258870700045&r=1&w=2
>
>  drivers/mmc/host/omap.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/omap.c b/drivers/mmc/host/omap.c
> index adf32682f27a..c60a7625b1fa 100644
> --- a/drivers/mmc/host/omap.c
> +++ b/drivers/mmc/host/omap.c
> @@ -104,6 +104,7 @@ struct mmc_omap_slot {
>         unsigned int            vdd;
>         u16                     saved_con;
>         u16                     bus_mode;
> +       u16                     power_mode;
>         unsigned int            fclk_freq;
>
>         struct tasklet_struct   cover_tasklet;
> @@ -1157,7 +1158,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>         struct mmc_omap_slot *slot = mmc_priv(mmc);
>         struct mmc_omap_host *host = slot->host;
>         int i, dsor;
> -       int clk_enabled;
> +       int clk_enabled, init_stream;
>
>         mmc_omap_select_slot(slot, 0);
>
> @@ -1167,6 +1168,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>                 slot->vdd = ios->vdd;
>
>         clk_enabled = 0;
> +       init_stream = 0;
>         switch (ios->power_mode) {
>         case MMC_POWER_OFF:
>                 mmc_omap_set_power(slot, 0, ios->vdd);
> @@ -1174,13 +1176,17 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>         case MMC_POWER_UP:
>                 /* Cannot touch dsor yet, just power up MMC */
>                 mmc_omap_set_power(slot, 1, ios->vdd);
> +               slot->power_mode = ios->power_mode;
>                 goto exit;
>         case MMC_POWER_ON:
>                 mmc_omap_fclk_enable(host, 1);
>                 clk_enabled = 1;
>                 dsor |= 1 << 11;
> +               if (slot->power_mode != MMC_POWER_ON)
> +                       init_stream = 1;
>                 break;
>         }
> +       slot->power_mode = ios->power_mode;
>
>         if (slot->bus_mode != ios->bus_mode) {
>                 if (slot->pdata->set_bus_mode != NULL)
> @@ -1196,7 +1202,7 @@ static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>         for (i = 0; i < 2; i++)
>                 OMAP_MMC_WRITE(host, CON, dsor);
>         slot->saved_con = dsor;
> -       if (ios->power_mode == MMC_POWER_ON) {
> +       if (init_stream) {
>                 /* worst case at 400kHz, 80 cycles makes 200 microsecs */
>                 int usecs = 250;
>
> @@ -1234,6 +1240,7 @@ static int mmc_omap_new_slot(struct mmc_omap_host *host, int id)
>         slot->host = host;
>         slot->mmc = mmc;
>         slot->id = id;
> +       slot->power_mode = MMC_POWER_UNDEFINED;
>         slot->pdata = &host->pdata->slots[id];
>
>         host->slots[id] = slot;
> --
> 2.17.0
>