While speed mode is changed, CMD13 cannot be guaranteed.

According to the spec., it is not recommended to use CMD13
to check the busy completion of the timing change.
If CMD13 is used in this case, CRC error must be ignored.

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 845ce7c533b901b0895a6bf4c5715c676c5cd902..b255f661064dd12e8096f30d8059aa8db6ebc3b3 100755 (executable)
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -365,6 +365,41 @@ int mmc_spi_set_crc(struct mmc_host *host, int use_crc)
        return err;
 }
 
+static int __mmc_send_status(struct mmc_card *card, u32 *status,bool ignore_crc)
+{
+       int err;
+       struct mmc_command cmd = {0};
+
+       BUG_ON(!card);
+       BUG_ON(!card->host);
+
+       cmd.opcode = MMC_SEND_STATUS;
+       if (!mmc_host_is_spi(card->host))
+               cmd.arg = card->rca << 16;
+       cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
+
+    if (ignore_crc)
+               cmd.flags &= ~MMC_RSP_CRC;
+
+       err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
+       if (err)
+               return err;
+
+       /* NOTE: callers are required to understand the difference
+        * between "native" and SPI format status words!
+        */
+       if (status)
+               *status = cmd.resp[0];
+
+       return 0;
+}
+
+int mmc_send_status(struct mmc_card *card, u32 *status)
+{
+       return __mmc_send_status(card, status, false);
+}
+
+
 /**
  *     mmc_switch - modify EXT_CSD register
  *     @card: the MMC card associated with the data transfer
@@ -382,6 +417,7 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
        int err;
        struct mmc_command cmd = {0};
        u32 status;
+    bool ignore_crc = false;
 
        BUG_ON(!card);
        BUG_ON(!card->host);
@@ -398,9 +434,19 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
        if (err)
                return err;
 
+    /*
+        * Must check status to be sure of no errors
+        * If CMD13 is to check the busy completion of the timing change,
+        * disable the check of CRC error.
+        */
+       if (index == EXT_CSD_HS_TIMING &&
+           !(card->host->caps & MMC_CAP_WAIT_WHILE_BUSY))
+               ignore_crc = true;
+    
+
        /* Must check status to be sure of no errors */
        do {
-               err = mmc_send_status(card, &status);
+               err = __mmc_send_status(card, &status,ignore_crc);
                if (err)
                        return err;
                if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
@@ -424,31 +470,6 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 }
 EXPORT_SYMBOL_GPL(mmc_switch);
 
-int mmc_send_status(struct mmc_card *card, u32 *status)
-{
-       int err;
-       struct mmc_command cmd = {0};
-
-       BUG_ON(!card);
-       BUG_ON(!card->host);
-
-       cmd.opcode = MMC_SEND_STATUS;
-       if (!mmc_host_is_spi(card->host))
-               cmd.arg = card->rca << 16;
-       cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
-
-       err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
-       if (err)
-               return err;
-
-       /* NOTE: callers are required to understand the difference
-        * between "native" and SPI format status words!
-        */
-       if (status)
-               *status = cmd.resp[0];
-
-       return 0;
-}
 
 static int
 mmc_send_bus_test(struct mmc_card *card, struct mmc_host *host, u8 opcode,