Re: [PATCH] mmc: Some Micron eMMC devices cause reboot to hang

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

On Tue, 21 Jul 2020 at 21:18, Al Cooper <alcooperx@gmail.com> wrote:
>
> When using eMMC as the boot device, some Micron eMMC devices will
> cause reboot to hang. This is a result of the eMMC device not going
> into boot mode after the hardware sends CMD0 to reset the eMMC
> device. This only happens if the kernel driver sends CMD5 (SLEEP_WAKE),
> to put the device into sleep state, before restarting the system.

What do you mean by "boot mode"?

When the kernel sends the CMD0 to wake up the eMMC from sleep, at
system resume for example, it all works fine, I guess. What is the
difference?

> The fix is to add a quirk that avoids sending the SLEEP command
> and to use MMC_FIXUP to set the quirk for these Micron devices.

I am not sure this is Micron device specific, but rather some it's a
driver/platform bug. Maybe on the kernel side or in the bootloader
code.

But, let's see where the discussion leads us.

Kind regards
Uffe

>
> Signed-off-by: Al Cooper <alcooperx@gmail.com>
> ---
>  drivers/mmc/core/mmc.c    | 3 ++-
>  drivers/mmc/core/quirks.h | 8 ++++++++
>  include/linux/mmc/card.h  | 1 +
>  3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 4203303f946a..4d69e8f8fe59 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1895,7 +1895,8 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>
>  static int mmc_can_sleep(struct mmc_card *card)
>  {
> -       return (card && card->ext_csd.rev >= 3);
> +       return card && card->ext_csd.rev >= 3 &&
> +               ((card->quirks & MMC_QUIRK_BROKEN_SLEEP) == 0);
>  }
>
>  static int mmc_sleep(struct mmc_host *host)
> diff --git a/drivers/mmc/core/quirks.h b/drivers/mmc/core/quirks.h
> index 472fa2fdcf13..7263187b6323 100644
> --- a/drivers/mmc/core/quirks.h
> +++ b/drivers/mmc/core/quirks.h
> @@ -99,6 +99,14 @@ static const struct mmc_fixup mmc_blk_fixups[] = {
>         MMC_FIXUP("V10016", CID_MANFID_KINGSTON, CID_OEMID_ANY, add_quirk_mmc,
>                   MMC_QUIRK_TRIM_BROKEN),
>
> +       /*
> +        * Some Micron eMMC devices will not go into boot mode on
> +        * CMD0 arg: 0XF0F0F0F0 after going into SLEEP state.
> +        * This will hang a reboot.
> +        */
> +       MMC_FIXUP(CID_NAME_ANY, CID_MANFID_NUMONYX, 0x014e, add_quirk_mmc,
> +                 MMC_QUIRK_BROKEN_SLEEP),
> +
>         END_FIXUP
>  };
>
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 7d46411ffaa2..0cdddcb5e17d 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -270,6 +270,7 @@ struct mmc_card {
>  #define MMC_QUIRK_BROKEN_IRQ_POLLING   (1<<11) /* Polling SDIO_CCCR_INTx could create a fake interrupt */
>  #define MMC_QUIRK_TRIM_BROKEN  (1<<12)         /* Skip trim */
>  #define MMC_QUIRK_BROKEN_HPI   (1<<13)         /* Disable broken HPI support */
> +#define MMC_QUIRK_BROKEN_SLEEP (1<<14)         /* Broken sleep mode */
>
>         bool                    reenable_cmdq;  /* Re-enable Command Queue */
>
> --
> 2.17.1
>