omap_hsmmc: recover from transfer failures

Timeouts during a command that has a data phase can result in the next
command issued after the command that failed not being processed, i.e.  no
interrupt ever occurs to indicate the command has completed.  This failure
can result in a deadlock.

This patch resets the data state machine to clear the error in case of a
command timeout.

Tested on OMAP3430 chip and intensive MMC/SD device removal while
transferring data.
Signed-off-by: NAndy Lowe <alowe@mvista.com>
Signed-off-by: NJean Pihet <jpihet@mvista.com>
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NPierre Ossman <drzeus@drzeus.cx>

drivers/mmc/host/omap_hsmmc.c

@@ -417,8 +417,15 @@ static irqreturn_t mmc_omap_irq(int irq, void *dev_id)
 				}
 				end_cmd = 1;
 			}
-			if (host->data)
+			if (host->data) {
 				mmc_dma_cleanup(host);
+				OMAP_HSMMC_WRITE(host->base, SYSCTL,
+					OMAP_HSMMC_READ(host->base,
+							SYSCTL) | SRD);
+				while (OMAP_HSMMC_READ(host->base,
+						SYSCTL) & SRD)
+					;
+			}
 		}
 		if ((status & DATA_TIMEOUT) ||
 			(status & DATA_CRC)) {