[PATCH v6 3/4] dmaengine: pl330: Store pointer to slave device

[Ulf Hansson]

On 24 January 2017 at 10:27, Marek Szyprowski <m.szyprowski at samsung.com> wrote:
> Store the pointer to slave device, which requested our channel. It will be
> later used to implement runtime PM of PL330 DMA controller. Although
> DMA channels might be requested many times, each DMA peripheral channel is
> physically dedicated only for specific hardware, so there should be only
> one slave device for each channel.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> Reviewed-by: Krzysztof Kozlowski <krzk at kernel.org>
> Acked-by: Arnd Bergmann <arnd at arndb.de>

Reviewed-by: Ulf Hansson <ulf.hansson at linaro.org>

Kind regards
Uffe

> ---
>  drivers/dma/pl330.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
> index b6b2cc912380..c77a3494659c 100644
> --- a/drivers/dma/pl330.c
> +++ b/drivers/dma/pl330.c
> @@ -450,6 +450,7 @@ struct dma_pl330_chan {
>
>         /* for runtime pm tracking */
>         bool active;
> +       struct device *slave;
>  };
>
>  struct pl330_dmac {
> @@ -2093,6 +2094,14 @@ static struct dma_chan *of_dma_pl330_xlate(struct of_phandle_args *dma_spec,
>         if (chan_id >= pl330->num_peripherals)
>                 return NULL;
>
> +       if (!pl330->peripherals[chan_id].slave) {
> +               pl330->peripherals[chan_id].slave = slave;
> +       } else if (pl330->peripherals[chan_id].slave != slave) {
> +               dev_err(pl330->ddma.dev,
> +                       "Can't use same channel with multiple slave devices!\n");
> +               return NULL;
> +       }
> +
>         return dma_get_slave_channel(&pl330->peripherals[chan_id].chan);
>  }
>
> --
> 1.9.1
>