[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>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index eb41391..6696f71 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -550,6 +550,11 @@
csd->capacity = (1 + m) << (e + 2);
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
+ csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
+ csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
+ csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
+ csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
+ csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
} else {
/*
* We only understand CSD structure v1.1 and v1.2.
@@ -579,6 +584,11 @@
csd->capacity = (1 + m) << (e + 2);
csd->read_blkbits = UNSTUFF_BITS(resp, 80, 4);
+ csd->read_partial = UNSTUFF_BITS(resp, 79, 1);
+ csd->write_misalign = UNSTUFF_BITS(resp, 78, 1);
+ csd->read_misalign = UNSTUFF_BITS(resp, 77, 1);
+ csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4);
+ csd->write_partial = UNSTUFF_BITS(resp, 21, 1);
}
}