On Jan 9, 2011, at 8:26 AM, Pierre Tardy wrote:

> Some sdio card are not following sdio standard, and does not work
> when the sdio bus's clock is gated
> 
> To keep functionnality for all legacy driver, we turn this quirk on
> for every sdio card.
> Drivers needs to disable the quirk manually when someone verified that their
> supported card works with clock gating.
> 
> Signed-off-by: Pierre Tardy <[email protected]>
> ---
> drivers/mmc/core/host.c   |    5 +----
> drivers/mmc/core/quirks.c |   11 +++++++++++
> include/linux/mmc/card.h  |    1 +
> 3 files changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index b3ac6c5..461e6a1 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -160,10 +160,7 @@ static bool mmc_host_may_gate_card(struct mmc_card *card)
>        * gate the clock, because there is somebody out there that may still
>        * be using it.
>        */
> -     if (mmc_card_sdio(card))
> -             return false;
> -
> -     return true;
> +     return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
> }


Since the code is not called that often could you change the above code to:  

>       if (mmc_card_sdio(card))
>               return !(card->quirks & MMC_QUIRK_BROKEN_CLK_GATING);
        return true;

more obvious that quirk only applies to sdio.

> 
> /**
> diff --git a/drivers/mmc/core/quirks.c b/drivers/mmc/core/quirks.c
> index d8a5fec..fe467c8 100644
> --- a/drivers/mmc/core/quirks.c
> +++ b/drivers/mmc/core/quirks.c
> @@ -32,7 +32,18 @@ static void add_quirk(struct mmc_card *card, int data)
>       card->quirks |= data;
> }
> 
> +/*
> + * This hook just adds a quirk for all sdio devices
> + */
> +static void add_quirk_for_sdio_devices(struct mmc_card *card, int data)
> +{
> +     if (mmc_card_sdio(card))
> +             card->quirks |= data;
> +}
> +
> static const struct mmc_fixup mmc_fixup_methods[] = {
> +     { SDIO_ANY_ID, SDIO_ANY_ID,
> +             add_quirk_for_sdio_devices, MMC_QUIRK_BROKEN_CLK_GATING }
>       { 0 }
> };
> 
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index a498d53..3fe9db0 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -121,6 +121,7 @@ struct mmc_card {
>                                               /* for byte mode */
> #define MMC_QUIRK_NONSTD_SDIO (1<<2)          /* non-standard SDIO card 
> attached */
>                                               /* (missing CIA registers) */
> +#define MMC_QUIRK_BROKEN_CLK_GATING (1<<3)   /* clock gating the sdio bus 
> will make card fail */
> 
>       unsigned int            erase_size;     /* erase size in sectors */
>       unsigned int            erase_shift;    /* if erase unit is power 2 */
> -- 
> 1.7.1
> 
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