Re: [PATCH 2/4] dmaengine: dw_dmac: move to generic DMA binding

From: Viresh Kumar
Date: Fri Feb 15 2013 - 22:26:25 EST


On 15 February 2013 23:51, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
> +- #dma-cells: must be <3>

> +DMA clients connected to the Designware DMA controller must use the format
> +described in the dma.txt file, using a five-cell specifier for each channel.

s/five/four ?

> +The four cells in order are:
> +
> +1. A phandle pointing to the DMA controller
> +2. The DMA request line number
> +3. Source master for transfers on allocated channel
> +4. Destination master for transfers on allocated channel

> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c

> +static bool dw_dma_generic_filter(struct dma_chan *chan, void *param)
> {

> + dws->cfg_hi = 0xffffffff;
> + dws->cfg_lo = 0xffffffff;

s/0xffffffff/-1 ?

> + dws->src_master = fargs->src;
> + dws->dst_master = fargs->dst;
> + dwc->req = fargs->req;
>
> - return true;
> - }
> - }
> + chan->private = dws;
> +
> + return true;
> +}
> +
> +static struct dma_chan *dw_dma_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct dw_dma *dw = ofdma->of_dma_data;
> + struct dw_dma_filter_args fargs = {
> + .dw = dw,
> + };
> + dma_cap_mask_t cap;
> +
> + if (dma_spec->args_count != 3)
> + return NULL;
> +
> + fargs.req = be32_to_cpup(dma_spec->args+0);
> + fargs.src = be32_to_cpup(dma_spec->args+1);
> + fargs.dst = be32_to_cpup(dma_spec->args+2);
> +
> + if (WARN_ON(fargs.req >= 16 || fargs.src >= 2 || fargs.dst >= 2))
> + return NULL;
>
> - last_dw = dw;
> - last_bus_id = param;
> - return false;
> + dma_cap_zero(cap);
> + dma_cap_set(DMA_SLAVE, cap);
> +
> + /* TODO: there should be a simpler way to do this */
> + return dma_request_channel(cap, dw_dma_generic_filter, &dma_spec->args[0]);
> }
> -EXPORT_SYMBOL(dw_dma_generic_filter);
>
> /* --------------------- Cyclic DMA API extensions -------------------- */
>
> @@ -1510,9 +1529,8 @@ static void dw_dma_off(struct dw_dma *dw)
> static struct dw_dma_platform_data *
> dw_dma_parse_dt(struct platform_device *pdev)
> {
> - struct device_node *sn, *cn, *np = pdev->dev.of_node;
> + struct device_node *np = pdev->dev.of_node;
> struct dw_dma_platform_data *pdata;
> - struct dw_dma_slave *sd;
> u32 tmp, arr[4];
>
> if (!np) {
> @@ -1524,7 +1542,7 @@ dw_dma_parse_dt(struct platform_device *pdev)
> if (!pdata)
> return NULL;
>
> - if (of_property_read_u32(np, "nr_channels", &pdata->nr_channels))
> + if (of_property_read_u32(np, "dma-channels", &pdata->nr_channels))
> return NULL;
--
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