[U-Boot] [PATCH] mmc: Fix mmc bus width

Mario Schuknecht mario.schuknecht at dresearch-fe.de
Tue Sep 30 17:04:42 CEST 2014


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 at dresearch-fe.de>
---
 drivers/mmc/mmc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index a26f3ce..d1faa9f 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1127,10 +1127,11 @@ 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] \
-- 
1.8.4.5



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