mmc: Fix mmc bus width

After setting the bus width, the extended CSD register is read. Some selected
fields are compared with previously read extended CSD register fields. In this
comparison the EXT_CSD_ERASE_GROUP_DEF field is compared. But this field is
previously written under certain circumstances. And then the comparison fails.

Only compare read-only fields. Therefore compare field EXT_CSD_HC_WP_GRP_SIZE
instead of field EXT_CSD_ERASE_GROUP_DEF.

Signed-off-by: Mario Schuknecht <mario.schuknecht@dresearch-fe.de>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index e4a28d4b4ae4105f10d757cae443a27dccf41c6d..44a4feb96e0446c2c65df569afb2b3c0294817de 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1134,10 +1134,11 @@ static int mmc_startup(struct mmc *mmc)
                        mmc_set_bus_width(mmc, widths[idx]);
 
                        err = mmc_send_ext_csd(mmc, test_csd);
+                       /* Only compare read only fields */
                        if (!err && ext_csd[EXT_CSD_PARTITIONING_SUPPORT] \
                                    == test_csd[EXT_CSD_PARTITIONING_SUPPORT]
-                                && ext_csd[EXT_CSD_ERASE_GROUP_DEF] \
-                                   == test_csd[EXT_CSD_ERASE_GROUP_DEF] \
+                                && ext_csd[EXT_CSD_HC_WP_GRP_SIZE] \
+                                   == test_csd[EXT_CSD_HC_WP_GRP_SIZE] \
                                 && ext_csd[EXT_CSD_REV] \
                                    == test_csd[EXT_CSD_REV]
                                 && ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] \