linux-kernel - [PATCH 5.4 46/61] mmc: dw_mmc: Fix hang on data CRC error

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Date:   Tue, 24 Aug 2021 13:00:51 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Vincent Whitchurch <vincent.whitchurch@...s.com>,
        Jaehoon Chung <jh80.chung@...sung.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 46/61] mmc: dw_mmc: Fix hang on data CRC error

From: Vincent Whitchurch <vincent.whitchurch@...s.com>

[ Upstream commit 25f8203b4be1937c4939bb98623e67dcfd7da4d1 ]

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@...s.com>
Reviewed-by: Jaehoon Chung <jh80.chung@...sung.com>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20210630102232.16011-1-vincent.whitchurch@axis.com
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/mmc/host/dw_mmc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 79c55c7b4afd..6ace82028667 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2017,8 +2017,8 @@ static void dw_mci_tasklet_func(unsigned long priv)
 					continue;
 				}
 
-				dw_mci_stop_dma(host);
 				send_stop_abort(host, data);
+				dw_mci_stop_dma(host);
 				state = STATE_SENDING_STOP;
 				break;
 			}
@@ -2042,10 +2042,10 @@ static void dw_mci_tasklet_func(unsigned long priv)
 			 */
 			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;
 			}
@@ -2078,10 +2078,10 @@ static void dw_mci_tasklet_func(unsigned long priv)
 			 */
 			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;
 			}
-- 
2.30.2