Re: [PATCH v2 1/4] mmc: mmci: Support any block sizes for ux500v2 and qcom variant

[Ulf Hansson]

On 19 August 2014 13:14, Srinivas Kandagatla
<srinivas.kandagatla@xxxxxxxxxx> wrote:
> From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>
> For the ux500v2 variant of the PL18x block, any block sizes are
> supported. This will make it possible to decrease data overhead
> for SDIO transfers.
>
> This patch is based on Ulf Hansson patch
> http://www.spinics.net/lists/linux-mmc/msg12160.html
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
>         enabled this support on qcom variant.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
>  drivers/mmc/host/mmci.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index c11cb05..3089fba 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -77,6 +77,7 @@ static unsigned int fmax = 515633;
>   * @qcom_fifo: enables qcom specific fifo pio read logic.
>   * @reversed_irq_handling: handle data irq before cmd irq.
>   * @qcom_dml: enables qcom specific dma glue for dma transfers.
> + * @any_blksize: true if block any sizes are supported
>   */
>  struct variant_data {
>         unsigned int            clkreg;
> @@ -102,6 +103,7 @@ struct variant_data {
>         bool                    qcom_fifo;
>         bool                    reversed_irq_handling;
>         bool                    qcom_dml;
> +       bool                    any_blksize;
>  };
>
>  static struct variant_data variant_arm = {
> @@ -194,6 +196,7 @@ static struct variant_data variant_ux500v2 = {
>         .pwrreg_clkgate         = true,
>         .busy_detect            = true,
>         .pwrreg_nopower         = true,
> +       .any_blksize            = true,
>  };

There are some prerequisites of the data buffers to supports any block
size, at least for ux500.
Try read up on this discussion:
http://marc.info/?t=135005062400002&r=2&w=2

The conclusion from the above is that we need to adopt
mmci_pio_write() to handle corner cases.

Now, I suppose, unless someone objects, we could go ahead and merge
this patch. Then you will have to fixup mmci_pio_write() later on.

Kind regards
Uffe
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