mmc: dw_mmc: Fix hang on data CRC error

When a Data CRC interrupt is received, the driver disables the DMA, then
sends the stop/abort command and then waits for Data Transfer Over.

However, sometimes, when a data CRC error is received in the middle of a
multi-block write transfer, the Data Transfer Over interrupt is never
received, and the driver hangs and never completes the request.

The driver sets the BMOD.SWR bit (SDMMC_IDMAC_SWRESET) when stopping the
DMA, but according to the manual CMD.STOP_ABORT_CMD should be programmed
"before assertion of SWR".  Do these operations in the recommended
order.  With this change the Data Transfer Over is always received
correctly in my tests.

Signed-off-by: Vincent Whitchurch <[email protected]>
Reviewed-by: Jaehoon Chung <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ulf Hansson <[email protected]>

Author: vwax

drivers/mmc/host/dw_mmc.c

@@ -2018,8 +2018,8 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t)
 					continue;
 				}
 
-				dw_mci_stop_dma(host);
 				send_stop_abort(host, data);
+				dw_mci_stop_dma(host);
 				state = STATE_SENDING_STOP;
 				break;
 			}
@@ -2043,10 +2043,10 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t)
 			 */
 			if (test_and_clear_bit(EVENT_DATA_ERROR,
 					       &host->pending_events)) {
-				dw_mci_stop_dma(host);
 				if (!(host->data_status & (SDMMC_INT_DRTO |
 							   SDMMC_INT_EBE)))
 					send_stop_abort(host, data);
+				dw_mci_stop_dma(host);
 				state = STATE_DATA_ERROR;
 				break;
 			}
@@ -2079,10 +2079,10 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t)
 			 */
 			if (test_and_clear_bit(EVENT_DATA_ERROR,
 					       &host->pending_events)) {
-				dw_mci_stop_dma(host);
 				if (!(host->data_status & (SDMMC_INT_DRTO |
 							   SDMMC_INT_EBE)))
 					send_stop_abort(host, data);
+				dw_mci_stop_dma(host);
 				state = STATE_DATA_ERROR;
 				break;
 			}