mmc_spi: don't use EINVAL for possible transmission errors

This patch changes the reported error code for the responses
to a command from EINVAL to EFAULT/ENOSYS, as EINVAL is reserved
for non-recoverable host errors, and the responses from
the SD/MMC card may be because of recoverable transmission
errors in the command or in the response. Response codes
in SPI mode are NOT protected by a checksum, so don't trust them.
Signed-off-by: Wolfgang Muees <wolfgang.mues@auerswald.de>
Acked-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

drivers/mmc/host/mmc_spi.c

@@ -335,15 +335,16 @@ static int mmc_spi_response_get(struct mmc_spi_host *host,
 
 	/* Status byte: the entire seven-bit R1 response.  */
 	if (cmd->resp[0] != 0) {
-		if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS
-				      | R1_SPI_ILLEGAL_COMMAND)
+		if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS)
 				& cmd->resp[0])
-			value = -EINVAL;
+			value = -EFAULT; /* Bad address */
+		else if (R1_SPI_ILLEGAL_COMMAND & cmd->resp[0])
+			value = -ENOSYS; /* Function not implemented */
 		else if (R1_SPI_COM_CRC & cmd->resp[0])
-			value = -EILSEQ;
+			value = -EILSEQ; /* Illegal byte sequence */
 		else if ((R1_SPI_ERASE_SEQ | R1_SPI_ERASE_RESET)
 				& cmd->resp[0])
-			value = -EIO;
+			value = -EIO;    /* I/O error */
 		/* else R1_SPI_IDLE, "it's resetting" */
 	}