sdio: add quirk to clamp byte mode transfer

Some SDIO cards expect byte transfers not to exceed the configured block
transfer size.  Add a quirk to that effect.

Patches to make use of this quirk will be sent separately.

Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 13 insertions, 1 deletions

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index f9aa8a7deffa..87c618904ee2 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -189,7 +189,12 @@ static inline unsigned int sdio_max_byte_size(struct sdio_func *func)
 {
         unsigned mval = min(func->card->host->max_seg_size,
                             func->card->host->max_blk_size);
-        mval = min(mval, func->max_blksize);
+
+        if (mmc_blksz_for_byte_mode(func->card))
+                mval = min(mval, func->cur_blksize);
+        else
+                mval = min(mval, func->max_blksize);
+
         return min(mval, 512u); /* maximum size for byte mode */
 }
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 2ee22e8af110..d02d2c6e0cfe 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -99,6 +99,8 @@ struct mmc_card {
 #define MMC_STATE_BLOCKADDR     (1<<3)          /* card uses block-addressing */
         unsigned int            quirks;         /* card 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 */
 
         u32                     raw_cid[4];     /* raw card CID */
         u32                     raw_csd[4];     /* raw card CSD */
@@ -139,6 +141,11 @@ static inline int mmc_card_lenient_fn0(const struct mmc_card *c)
         return c->quirks & MMC_QUIRK_LENIENT_FN0;
 }
 
+static inline int mmc_blksz_for_byte_mode(const struct mmc_card *c)
+{
+        return c->quirks & MMC_QUIRK_BLKSZ_FOR_BYTE_MODE;
+}
+
 #define mmc_card_name(c)        ((c)->cid.prod_name)
 #define mmc_card_id(c)          (dev_name(&(c)->dev))