---

yaml
---
r: 219031
b: refs/heads/master
c: 061c6c8
h: refs/heads/master
i:
  219029: 5580ee3
  219027: cfdc7a4
  219023: c3589db
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 95f25efe0ce22e28d61722d655d2ef582f5f7520
+refs/heads/master: 061c6c847eeb11743e489a16e907b41c6f9042b6

trunk/drivers/mmc/host/mmc_spi.c

@@ -1055,6 +1055,8 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
 {
 	struct mmc_spi_host	*host = mmc_priv(mmc);
 	int			status = -EINVAL;
+	int			crc_retry = 5;
+	struct mmc_command	stop;
 
 #ifdef DEBUG
 	/* MMC core and layered drivers *MUST* issue SPI-aware commands */
@@ -1087,10 +1089,29 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	/* request exclusive bus access */
 	spi_bus_lock(host->spi->master);
 
+crc_recover:
 	/* issue command; then optionally data and stop */
 	status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
 	if (status == 0 && mrq->data) {
 		mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz);
+
+		/*
+		 * The SPI bus is not always reliable for large data transfers.
+		 * If an occasional crc error is reported by the SD device with
+		 * data read/write over SPI, it may be recovered by repeating
+		 * the last SD command again. The retry count is set to 5 to
+		 * ensure the driver passes stress tests.
+		 */
+		if (mrq->data->error == -EILSEQ && crc_retry) {
+			stop.opcode = MMC_STOP_TRANSMISSION;
+			stop.arg = 0;
+			stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+			status = mmc_spi_command_send(host, mrq, &stop, 0);
+			crc_retry--;
+			mrq->data->error = 0;
+			goto crc_recover;
+		}
+
 		if (mrq->stop)
 			status = mmc_spi_command_send(host, mrq, mrq->stop, 0);
 		else