[PATCH] mmc: dw_mmc: Reset DMA before enabling IDMAC

Doug Anderson dianders at chromium.org
Mon Oct 6 11:11:05 PDT 2014


Sonny,

On Mon, Oct 6, 2014 at 10:53 AM, Sonny Rao <sonnyrao at chromium.org> wrote:
> We've already got a reset of DMA after it's done.  Add one before we
> start DMA too.  This fixes a data corruption on Rockchip SoCs which
> will get bad data when doing a DMA transfer after doing a PIO transfer.
>
> We tested this on an Exynos 5800 with HS200 and didn't notice any
> difference in sequential read throughput.
>
> Signed-off-by: Sonny Rao <sonnyrao at chromium.org>
> Signed-off-by: Doug Anderson <dianders at chromium.org>
> ---
>  drivers/mmc/host/dw_mmc.c | 4 ++++
>  1 file changed, 4 insertions(+)

Reviewed-by: Doug Anderson <dianders at chromium.org>
Tested-by: Doug Anderson <dianders at chromium.org>



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