On 22 May 2017 at 11:09, Phil Elwell <phil@xxxxxxxxxxxxxxx> wrote:
> since:
> commit 0589342c27944e50ebd7a54f5215002b6598b748
> Author: Rob Herring <rob.herring@xxxxxxxxxxx>
> Date: Tue Oct 29 23:36:46 2013 -0500
>
> of: set dma_mask to point to coherent_dma_mask
>
> Platform devices created by DT code don't initialize dma_mask pointer to
> anything. Set it to coherent_dma_mask by default if the architecture
> code has not set it.
>
> the mmc-spi driver no longer detects the sd-cards any longer.
>
> This patch disables the offending section in mmc_spi
> so that the driver works again and detects the sd card normally.
>
> There is no real negative impact as the spi-framework
> does no longer rely on driver-provided DMA mappings but
> maps the transfers transparently.
>
> Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
> Submitted-by: Phil Elwell <phil@xxxxxxxxxxxxxxx>
> ---
> drivers/mmc/host/mmc_spi.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
> index ae19d83bb9de0..16946e2513afa 100644
> --- a/drivers/mmc/host/mmc_spi.c
> +++ b/drivers/mmc/host/mmc_spi.c
> @@ -1387,6 +1387,16 @@ static int mmc_spi_probe(struct spi_device *spi)
> if (!host->data)
> goto fail_nobuf1;
>
> + /* for some reason mmc_spi does not work with this enabled
> + * it is not needed anyway, as the SPI framework does DMA
> + * transfers now automatically
> + * the patch that introduced this was:
> + * commit 0589342c27944e50ebd7a54f5215002b6598b748
> + * Author: Rob Herring <rob.herring@xxxxxxxxxxx>
> + * Date: Tue Oct 29 23:36:46 2013 -0500
> + * of: set dma_mask to point to coherent_dma_mask
> + */
> +#if 0
> if (spi->master->dev.parent->dma_mask) {
> struct device *dev = spi->master->dev.parent;
>
> @@ -1402,6 +1412,7 @@ static int mmc_spi_probe(struct spi_device *spi)
> host->data_dma, sizeof(*host->data),
> DMA_BIDIRECTIONAL);
> }
> +#endif
>
> /* setup message for status/busy readback */
> spi_message_init(&host->readback);
Phil, I am not sure how to go with this.
Your change drops the dma implementation in the mmc_spi driver as
host->dma_dev now never gets assigned. I do think that makes sense as
the dma support should be implemented in the spi master driver and not
in the spi client driver, which currently is the case for mmc_spi.
Then perhaps a more proper change would be to remove the dma
implementation in mmc_spi altogether?
And one more thing, next time also cc the spi-list and Mark Brown, to
try to some broader input.
Kind regards
Uffe
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