mmc: add additional quirk for APP_CMD retry

It was observed (on ClearFog Base) that sending MMC APP_CMD returned
an error on the first attempt. The issue appears to be timing related
since even inserting a puts() short debug entry before the execution
added sufficient delay to receive success on first attempt.

Follow the existing quirks pattern to retry if initial issuance
failed so as to not introduce any delay unless needed.

Signed-off-by: Joel Johnson <mrjoel@lixil.net>

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index f683b52..d43983d 100644 (file)
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -1444,6 +1444,20 @@ static int sd_read_ssr(struct mmc *mmc)
        cmd.cmdarg = mmc->rca << 16;
 
        err = mmc_send_cmd(mmc, &cmd, NULL);
+#ifdef CONFIG_MMC_QUIRKS
+       if (err && (mmc->quirks & MMC_QUIRK_RETRY_APP_CMD)) {
+               int retries = 4;
+               /*
+                * It has been seen that APP_CMD may fail on the first
+                * attempt, let's try a few more times
+                */
+               do {
+                       err = mmc_send_cmd(mmc, &cmd, NULL);
+                       if (!err)
+                               break;
+               } while (retries--);
+       }
+#endif
        if (err)
                return err;
 
@@ -2755,7 +2769,8 @@ int mmc_get_op_cond(struct mmc *mmc)
 
 #ifdef CONFIG_MMC_QUIRKS
        mmc->quirks = MMC_QUIRK_RETRY_SET_BLOCKLEN |
-                     MMC_QUIRK_RETRY_SEND_CID;
+                     MMC_QUIRK_RETRY_SEND_CID |
+                     MMC_QUIRK_RETRY_APP_CMD;
 #endif
 
        err = mmc_power_cycle(mmc);

diff --git a/include/mmc.h b/include/mmc.h
index 1a9efe4..b5cb514 100644 (file)
--- a/include/mmc.h
+++ b/include/mmc.h
@@ -331,6 +331,7 @@ static inline bool mmc_is_tuning_cmd(uint cmdidx)
 
 #define MMC_QUIRK_RETRY_SEND_CID       BIT(0)
 #define MMC_QUIRK_RETRY_SET_BLOCKLEN   BIT(1)
+#define MMC_QUIRK_RETRY_APP_CMD        BIT(2)
 
 enum mmc_voltage {
        MMC_SIGNAL_VOLTAGE_000 = 0,