mmc: dw_mmc: protect a sequence of request and request-done.

Response timeout (RTO), Response crc error (RCRC) and Response error (RE)
signals come with command done (CD) and can be raised preceding command
done (CD). That is these error interrupts and CD can be handled in
separate dw_mci_interrupt(). If mmc_request_done() is called because of
a response timeout before command done has occured, we might send the
next request before the CD of current request is finished. This can
bring about a broken sequence of request and request-done.

And Data error interrupt (DRTO, DCRC, SBE, EBE) and data transfer
over (DTO) have the same problem.

Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/dw_mmc.c

@@ -1202,7 +1202,6 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 			host->cmd_status = status;
 			smp_wmb();
 			set_bit(EVENT_CMD_COMPLETE, &host->pending_events);
-			tasklet_schedule(&host->tasklet);
 		}
 
 		if (pending & DW_MCI_DATA_ERROR_FLAGS) {
@@ -1211,7 +1210,9 @@ static irqreturn_t dw_mci_interrupt(int irq, void *dev_id)
 			host->data_status = status;
 			smp_wmb();
 			set_bit(EVENT_DATA_ERROR, &host->pending_events);
-			tasklet_schedule(&host->tasklet);
+			if (!(pending & (SDMMC_INT_DTO | SDMMC_INT_DCRC |
+					 SDMMC_INT_SBE | SDMMC_INT_EBE)))
+				tasklet_schedule(&host->tasklet);
 		}
 
 		if (pending & SDMMC_INT_DATA_OVER) {