This patch adds a quirk to limit clock rate which
can be used to reduce the SDIO clock rate for some
chips with broken UHS.
Signed-off-by: Harish Jenny K N <harish_kandiga@xxxxxxxxxx>
---
drivers/mmc/core/card.h | 6 ++++++
drivers/mmc/core/sdio.c | 6 +++++-
include/linux/mmc/card.h | 1 +
3 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/core/card.h b/drivers/mmc/core/card.h
index 9c821ee..1170feb 100644
--- a/drivers/mmc/core/card.h
+++ b/drivers/mmc/core/card.h
@@ -149,6 +149,12 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
card->quirks &= ~data;
}
+static inline void __maybe_unused add_limit_rate_quirk(struct mmc_card *card,
+ int data)
+{
+ card->quirk_max_rate = data;
+}
+
/*
* Quirk add/remove for MMC products.
*/
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
index c599a62..24b510b 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 int max_rate;
/*
* If the host doesn't support any of the UHS-I modes, fallback on
@@ -500,9 +501,12 @@ static int sdio_set_bus_speed_mode(struct mmc_card *card)
if (err)
return err;
+ max_rate = min_not_zero(card->quirk_max_rate,
+ card->sw_caps.uhs_max_dtr);
+
if (bus_speed) {
mmc_set_timing(card->host, timing);
- mmc_set_clock(card->host, card->sw_caps.uhs_max_dtr);
+ mmc_set_clock(card->host, max_rate);
}
return 0;
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 279b390..5ebc478 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -252,6 +252,7 @@ struct mmc_card {
#define MMC_TYPE_SD_COMBO 3 /* SD combo (IO+mem) card */
unsigned int state; /* (our) card state */
unsigned int quirks; /* card quirks */
+ unsigned int quirk_max_rate; /* max rate set by quirks */
#define MMC_QUIRK_LENIENT_FN0 (1<<0) /* allow SDIO FN0 writes outside of the VS CCCR range */
#define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1) /* use func->cur_blksize */
/* for byte mode */
--
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
