Re: [PATCH] mmc: dw_mmc: Fix hang on data CRC error

[Ulf Hansson]

On Wed, 30 Jun 2021 at 12:22, Vincent Whitchurch
<vincent.whitchurch@xxxxxxxx> wrote:
>
> 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@xxxxxxxx>

Applied for fixes and by adding a stable tag, thanks!

Kind regards
Uffe


> ---
>  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 f85271f5c4fa..845b0745ea37 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2083,8 +2083,8 @@ 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;
>                         }
> @@ -2108,10 +2108,10 @@ 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;
>                         }
> @@ -2144,10 +2144,10 @@ 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;
>                         }
> --
> 2.28.0
>