[MMC] Improve MMC card block size selection

Select a block size for IO based on the read and write block size
combinations, and whether the card supports partial block reads
and/or partial block writes.

If we are able to satisfy block reads but not block writes, mark
the device read only.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 18fc77f682de..7f7d40684288 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -30,7 +30,12 @@ struct mmc_csd {
         unsigned int            tacc_ns;
         unsigned int            max_dtr;
         unsigned int            read_blkbits;
+        unsigned int            write_blkbits;
         unsigned int            capacity;
+        unsigned int            read_partial:1,
+                                read_misalign:1,
+                                write_partial:1
+                                write_misalign:1;
 };
 
 struct sd_scr {