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 <vincent.whitchurch@axis.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210630102232.16011-1-vincent.whitchurch@axis.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index d333130..c3229d8 100644 (file)
--- a/drivers/mmc/host/dw_mmc.c
+++ b/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;
                        }