mmc: mmc: Relax checking for switch errors after HS200 switch

The JEDEC specification indicates CMD13 can be used after a HS200 switch
to check for errors. However in practice some boards experience CRC errors
in the CMD13 response. Consequently, for HS200, CRC errors are not a
reliable way to know the switch failed. If there really is a problem, we
would expect tuning will fail and the result ends up the same. So change
the error condition to ignore CRC errors in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

3 files changed, 22 insertions, 3 deletions

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 033e00abe93f..b61b52f9da3d 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1240,7 +1240,12 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 
         mmc_set_timing(host, MMC_TIMING_MMC_HS200);
 
-        err = mmc_switch_status(card);
+        /*
+         * For HS200, CRC errors are not a reliable way to know the switch
+         * failed. If there really is a problem, we would expect tuning will
+         * fail and the result ends up the same.
+         */
+        err = __mmc_switch_status(card, false);
         if (err)
                 goto out_err;
 
@@ -1403,7 +1408,13 @@ static int mmc_select_hs200(struct mmc_card *card)
                 old_timing = host->ios.timing;
                 mmc_set_timing(host, MMC_TIMING_MMC_HS200);
 
-                err = mmc_switch_status(card);
+                /*
+                 * For HS200, CRC errors are not a reliable way to know the
+                 * switch failed. If there really is a problem, we would expect
+                 * tuning will fail and the result ends up the same.
+                 */
+                err = __mmc_switch_status(card, false);
+
                 /*
                  * mmc_select_timing() assumes timing has not changed if
                  * it is a switch error.
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index cb7006feb5c4..81ce63bb0773 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -431,18 +431,25 @@ static int mmc_switch_status_error(struct mmc_host *host, u32 status)
 }
 
 /* Caller must hold re-tuning */
-int mmc_switch_status(struct mmc_card *card)
+int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal)
 {
         u32 status;
         int err;
 
         err = mmc_send_status(card, &status);
+        if (!crc_err_fatal && err == -EILSEQ)
+                return 0;
         if (err)
                 return err;
 
         return mmc_switch_status_error(card->host, status);
 }
 
+int mmc_switch_status(struct mmc_card *card)
+{
+        return __mmc_switch_status(card, true);
+}
+
 static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
                         bool send_status, bool retry_crc_err)
 {
diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
index 761cb69c46af..abd525ed74be 100644
--- a/drivers/mmc/core/mmc_ops.h
+++ b/drivers/mmc/core/mmc_ops.h
@@ -28,6 +28,7 @@ int mmc_bus_test(struct mmc_card *card, u8 bus_width);
 int mmc_send_hpi_cmd(struct mmc_card *card, u32 *status);
 int mmc_can_ext_csd(struct mmc_card *card);
 int mmc_switch_status(struct mmc_card *card);
+int __mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);
 int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
                 unsigned int timeout_ms, unsigned char timing,
                 bool use_busy_signal, bool send_status, bool retry_crc_err);