From: Weijun Yang <york.yang@xxxxxxx>
This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 4324f6de6d2eb9b232410eb0d67bfafdde8ba711 ]
As SD Specifications Part1 Physical Layer Specification Version
3.01 says, CMD19 tuning is available for unlocked cards in transfer
state of 1.8V signaling mode. The small difference between v3.00
and 3.01 spec means that CMD19 tuning is also available for DDR50
mode.
Signed-off-by: Weijun Yang <york.yang@xxxxxxx>
Signed-off-by: Barry Song <Baohua.Song@xxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/mmc/core/sd.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 7907544..560c895 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -661,9 +661,25 @@ static int mmc_sd_init_uhs_card(struct mmc_card *card)
* SDR104 mode SD-cards. Note that tuning is mandatory for SDR104.
*/
if (!mmc_host_is_spi(card->host) &&
- (card->sd_bus_speed == UHS_SDR50_BUS_SPEED ||
- card->sd_bus_speed == UHS_SDR104_BUS_SPEED))
+ (card->sd_bus_speed == UHS_SDR50_BUS_SPEED ||
+ card->sd_bus_speed == UHS_DDR50_BUS_SPEED ||
+ card->sd_bus_speed == UHS_SDR104_BUS_SPEED)) {
err = mmc_execute_tuning(card);
+
+ /*
+ * As SD Specifications Part1 Physical Layer Specification
+ * Version 3.01 says, CMD19 tuning is available for unlocked
+ * cards in transfer state of 1.8V signaling mode. The small
+ * difference between v3.00 and 3.01 spec means that CMD19
+ * tuning is also available for DDR50 mode.
+ */
+ if (err && card->sd_bus_speed == UHS_DDR50_BUS_SPEED) {
+ pr_warn("%s: ddr50 tuning failed\n",
+ mmc_hostname(card->host));
+ err = 0;
+ }
+ }
+
out:
kfree(status);
--
2.5.0
--
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