mmc: card: Skip regular block io operations for RPMB partitions

Idea behind this patch is to skip all the regular block io operations
for RPMB partitions because these are not regular partitions and require
a different command sequence for reading and writing. RPMB partitions
should only be accessed via ioctl. Without this patch we see following
issues with some eMMC devices

dd if=/dev/mmcblk1rpmb of=/dev/null bs=1 count=1
[  124.185513] mmcblk1rpmb: error -110 transferring data, sector 0, nr 32, cmd response 0x900, card status 0xb00
[  124.195506] mmcblk1rpmb: retrying using single block read
[  124.201035] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.208559] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.216049] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.223567] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.231087] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.238600] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  124.246012] end_request: I/O error, dev mmcblk1rpmb, sector 0
[  124.251773] Buffer I/O error on device mmcblk1rpmb, logical block 0
[  124.258065] end_request: I/O error, dev mmcblk1rpmb, sector 8
[  124.263822] Buffer I/O error on device mmcblk1rpmb, logical block 1
[  124.270102] end_request: I/O error, dev mmcblk1rpmb, sector 16
[  124.275944] Buffer I/O error on device mmcblk1rpmb, logical block 2
[  124.282222] end_request: I/O error, dev mmcblk1rpmb, sector 24
[  124.288064] Buffer I/O error on device mmcblk1rpmb, logical block 3
[  129.717711] mmcblk1rpmb: error -110 transferring data, sector 0, nr 8, cmd response 0x900, card status 0xb00
[  129.727590] mmcblk1rpmb: retrying using single block read
[  129.733088] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.740605] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.748121] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.755612] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.763125] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.770639] mmcblk1rpmb: timed out sending r/w cmd command, card status 0x400900
[  129.778073] end_request: I/O error, dev mmcblk1rpmb, sector 0
[  129.783834] Buffer I/O error on device mmcblk1rpmb, logical block 0
dd: /dev/mmcblk1rpmb: Input/output error

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 1fa4c80..c0f16c7 100644 (file)
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -2019,6 +2019,13 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
                /* claim host only for the first request */
                mmc_get_card(card);
 
+       if (md->area_type & MMC_BLK_DATA_AREA_RPMB) {
+               if (req)
+                       blk_end_request_all(req, 0);
+               ret = 0;
+               goto out;
+       }
+
        ret = mmc_blk_part_switch(card, md);
        if (ret) {
                if (req) {