[PATCH RFC 1/3] mmc: core: Try harder if transfer mode switch fails

[Adrian Hunter <adrian.hunter@intel.com>]

Add extra busy wait and retries if transfer mode switch fails.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/mmc_ops.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index aa0cab190cd8..619088a94688 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -599,6 +599,12 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 		cmd.sanitize_busy = true;
 
 	err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
+	if (err && index == EXT_CSD_HS_TIMING) {
+		/* Try harder for timing changes */
+		__mmc_poll_for_busy(card, timeout_ms, send_status,
+				    retry_crc_err, MMC_BUSY_CMD6);
+		err = mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES);
+	}
 	if (err)
 		goto out;
 
-- 
2.17.1