On 4 April 2018 at 19:00, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
> From: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
>
> If we detect an incompatible scatterlist, we should fall back to PIO,
> too.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
> ---
>
> I found this while working on the RX DMA issue. I don't see a reason why we
> shouldn't fall back in this case as well. But maybe I am missing something.
>
> Shimoda-san: what do you think?
>
> drivers/mmc/host/renesas_sdhi_internal_dmac.c | 6 +-----
> 1 file changed, 1 insertion(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/renesas_sdhi_internal_dmac.c b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> index 380570a26a09..561e90755a3b 100644
> --- a/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> +++ b/drivers/mmc/host/renesas_sdhi_internal_dmac.c
> @@ -161,11 +161,7 @@ renesas_sdhi_internal_dmac_start_dma(struct tmio_mmc_host *host,
> enum dma_data_direction dir;
> int ret;
>
> - /* This DMAC cannot handle if sg_len is not 1 */
> - WARN_ON(host->sg_len > 1);
> -
> - /* This DMAC cannot handle if buffer is not 8-bytes alignment */
> - if (!IS_ALIGNED(sg->offset, 8))
> + if (WARN_ON(host->sg_len > 1) || !IS_ALIGNED(sg->offset, 8))
The WARN_ON becomes a bit misleading being a part of the if statement,
as it should never happen when the driver has set ->max_segs = 1.
For the alignment check, and the moving to PIO, this certainly makes
sense to me.
> goto force_pio;
>
> if (data->flags & MMC_DATA_READ) {
Kind regards
Uffe
