On 3 April 2018 at 13:34, Harish Jenny K N <harish_kandiga@xxxxxxxxxx> wrote:
> This patch adds a quirk to handle broken UHS which
> can be used to reduce the SDIO clock rate for some
> chips with broken UHS.
I would rather not limit the quirk to UHS mode, but instead make it a
generic quirk for limiting the clock frequency for a card. I believe
this will be useful for any error prone cards.
Hence, I suggest to re-name the quirk to "MMC_QUIRK_LIMIT_CLK_RATE".
Additionally, while adding the quirk, let's make it possible to pick
the clock rate depending on the "card id" as to avoid having one quirk
per frequency.
Kind regards
Uffe
>
> Signed-off-by: Harish Jenny K N <harish_kandiga@xxxxxxxxxx>
> ---
> drivers/mmc/core/card.h | 5 +++++
> drivers/mmc/core/sdio.c | 19 +++++++++++++++++++
> include/linux/mmc/card.h | 2 ++
> 3 files changed, 26 insertions(+)
>
> diff --git a/drivers/mmc/core/card.h b/drivers/mmc/core/card.h
> index 9c821ee..e6c7dad 100644
> --- a/drivers/mmc/core/card.h
> +++ b/drivers/mmc/core/card.h
> @@ -221,4 +221,9 @@ static inline int mmc_card_broken_hpi(const struct mmc_card *c)
> return c->quirks & MMC_QUIRK_BROKEN_HPI;
> }
>
> +static inline int mmc_card_broken_uhs(const struct mmc_card *c)
> +{
> + return c->quirks & MMC_QUIRK_BROKEN_UHS;
> +}
> +
> #endif
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index c599a62..d3fcc4c 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -444,6 +444,7 @@ static int sdio_set_bus_speed_mode(struct mmc_card *card)
> unsigned int bus_speed, timing;
> int err;
> unsigned char speed;
> + unsigned char cccr;
>
> /*
> * If the host doesn't support any of the UHS-I modes, fallback on
> @@ -460,6 +461,24 @@ static int sdio_set_bus_speed_mode(struct mmc_card *card)
> timing = MMC_TIMING_UHS_SDR104;
> card->sw_caps.uhs_max_dtr = UHS_SDR104_MAX_DTR;
> card->sd_bus_speed = UHS_SDR104_BUS_SPEED;
> +
> + err = mmc_io_rw_direct(card, 0, 0, SDIO_CCCR_CCCR,
> + 0, &cccr);
> + if (err)
> + return err;
> +
> + if ((cccr & 0x0f) >= SDIO_CCCR_REV_3_00) {
> + if (mmc_host_uhs(card->host) &&
> + mmc_card_broken_uhs(card)) {
> + /*
> + * Reduce the max clock rate to
> + * 150MHz for SD_MODE_UHS_SDR104.
> + */
> + card->sw_caps.uhs_max_dtr =
> + UHS_SDR104_REDUCED_DTR;
> + }
> + }
> +
> } else if ((card->host->caps & MMC_CAP_UHS_DDR50) &&
> (card->sw_caps.sd3_bus_mode & SD_MODE_UHS_DDR50)) {
> bus_speed = SDIO_SPEED_DDR50;
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 279b390..daab735 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -152,6 +152,7 @@ struct sd_switch_caps {
> unsigned int uhs_max_dtr;
> #define HIGH_SPEED_MAX_DTR 50000000
> #define UHS_SDR104_MAX_DTR 208000000
> +#define UHS_SDR104_REDUCED_DTR 150000000
> #define UHS_SDR50_MAX_DTR 100000000
> #define UHS_DDR50_MAX_DTR 50000000
> #define UHS_SDR25_MAX_DTR UHS_DDR50_MAX_DTR
> @@ -268,6 +269,7 @@ 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_UHS (1<<14) /* Broken UHS */
>
> bool reenable_cmdq; /* Re-enable Command Queue */
>
> --
> 1.9.1
>
>
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