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>

1 files changed, 6 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 */
 }