On 03/31/2013 06:17 PM, Anatolij Gustschin wrote:
> Add generic DMA bindings and register the DMA controller
> to DT DMA helpers.
>
> Signed-off-by: Anatolij Gustschin <ag...@denx.de>
> ---
> arch/powerpc/boot/dts/mpc5121.dtsi | 5 ++-
> drivers/dma/mpc512x_dma.c | 63
> ++++++++++++++++++++++++++++++++++--
> 2 files changed, 64 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi
> b/arch/powerpc/boot/dts/mpc5121.dtsi
> index 723e292..d1fe070 100644
> --- a/arch/powerpc/boot/dts/mpc5121.dtsi
> +++ b/arch/powerpc/boot/dts/mpc5121.dtsi
> @@ -384,10 +384,13 @@
> interrupts = <40 0x8>;
> };
>
> - dma@14000 {
> + dma0: dma@14000 {
> compatible = "fsl,mpc5121-dma";
> reg = <0x14000 0x1800>;
> interrupts = <65 0x8>;
> + #dma-cells = <1>;
> + #dma-channels = <64>;
> + #dma-requests = <64>;
> };
> };
>
> diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
> index 2d95673..bc6c356 100644
> --- a/drivers/dma/mpc512x_dma.c
> +++ b/drivers/dma/mpc512x_dma.c
> @@ -40,6 +40,7 @@
> #include <linux/io.h>
> #include <linux/slab.h>
> #include <linux/of_device.h>
> +#include <linux/of_dma.h>
> #include <linux/of_platform.h>
>
> #include <linux/random.h>
> @@ -641,6 +642,44 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t
> dst, dma_addr_t src,
> return &mdesc->desc;
> }
>
> +struct mpc_dma_filter_args {
> + struct mpc_dma *mdma;
> + unsigned int chan_id;
> +};
> +
> +static bool mpc_dma_filter(struct dma_chan *chan, void *param)
> +{
> + struct mpc_dma_filter_args *fargs = param;
> +
> + if (chan->device != &fargs->mdma->dma)
> + return false;
> +
> + return (chan->chan_id == fargs->chan_id);
> +}
> +
> +static struct dma_chan *mpc_dma_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + int count = dma_spec->args_count;
> + struct mpc_dma *mdma = ofdma->of_dma_data;
> + struct mpc_dma_filter_args fargs;
> + dma_cap_mask_t cap;
> +
> + if (!mdma)
> + return NULL;
> +
> + if (count != 1)
> + return NULL;
> +
> + fargs.mdma = mdma;
> + fargs.chan_id = dma_spec->args[0];
> +
> + dma_cap_zero(cap);
> + dma_cap_set(DMA_SLAVE, cap);
> +
> + return dma_request_channel(cap, mpc_dma_filter, &fargs);
> +}
> +
This is more or less the same as the generic of_dma_xlate_by_chan_id
function I posted about two weeks ago:
https://patchwork.kernel.org/patch/2331091/
Vinod, can you take a look at that patch again? I'm not quite sure what you
meant by your question 'how will the client know which "id" to request?'.
- Lars
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