[PATCH 3.16 070/306] mmc: block: don't use CMD23 with very old MMC cards

From: Ben Hutchings
Date: Wed Feb 15 2017 - 18:39:57 EST

3.16.40-rc1 review patch. If anyone has any objections, please let me know.


From: Daniel GlÃckner <dg@xxxxxxxxx>

commit 0ed50abb2d8fc81570b53af25621dad560cd49b3 upstream.

CMD23 aka SET_BLOCK_COUNT was introduced with MMC v3.1.
Older versions of the specification allowed to terminate
multi-block transfers only with CMD12.

The patch fixes the following problem:

mmc0: new MMC card at address 0001
mmcblk0: mmc0:0001 SDMB-16 15.3 MiB
mmcblk0: timed out sending SET_BLOCK_COUNT command, card status 0x400900
blk_update_request: I/O error, dev mmcblk0, sector 0
Buffer I/O error on dev mmcblk0, logical block 0, async page read
mmcblk0: unable to read partition table

Signed-off-by: Daniel GlÃckner <dg@xxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
drivers/mmc/card/block.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2170,7 +2170,8 @@ static struct mmc_blk_data *mmc_blk_allo
set_capacity(md->disk, size);

if (mmc_host_cmd23(card->host)) {
- if (mmc_card_mmc(card) ||
+ if ((mmc_card_mmc(card) &&
+ card->csd.mmca_vsn >= CSD_SPEC_VER_3) ||
(mmc_card_sd(card) &&
card->scr.cmds & SD_SCR_CMD23_SUPPORT))
md->flags |= MMC_BLK_CMD23;