Re: [PATCH v4 4/4] dmaengine: mediatek-cqdma: add dma mask for capability

[Matthias Brugger <matthias.bgg@gmail.com>]

On 28/05/2020 11:57, EastL wrote:
> This patch add dma mask for capability.
> 
> Change-Id: I31f4622f9541d769702029532e5f5f185815dda2

No Change-Id in the commit message please.

> Signed-off-by: EastL <EastL.Lee@mediatek.com>
> ---
>  drivers/dma/mediatek/mtk-cqdma.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
> index bca7118..1805a76 100644
> --- a/drivers/dma/mediatek/mtk-cqdma.c
> +++ b/drivers/dma/mediatek/mtk-cqdma.c
> @@ -117,6 +117,7 @@ struct mtk_cqdma_vchan {
>   * @clk:                    The clock that device internal is using
>   * @dma_requests:           The number of VCs the device supports to
>   * @dma_channels:           The number of PCs the device supports to
> + * @dma_mask:               A mask for DMA capability
>   * @vc:                     The pointer to all available VCs
>   * @pc:                     The pointer to all the underlying PCs
>   */
> @@ -126,6 +127,7 @@ struct mtk_cqdma_device {
>  
>  	u32 dma_requests;
>  	u32 dma_channels;
> +	u32 dma_mask;
>  	struct mtk_cqdma_vchan *vc;
>  	struct mtk_cqdma_pchan **pc;
>  };
> @@ -549,6 +551,7 @@ static void mtk_cqdma_hw_deinit(struct mtk_cqdma_device *cqdma)
>  };
>  MODULE_DEVICE_TABLE(of, mtk_cqdma_match);
>  
> +static u64 cqdma_dmamask;
>  static int mtk_cqdma_probe(struct platform_device *pdev)
>  {
>  	struct mtk_cqdma_device *cqdma;
> @@ -607,6 +610,16 @@ static int mtk_cqdma_probe(struct platform_device *pdev)
>  		cqdma->dma_channels = MTK_CQDMA_NR_PCHANS;
>  	}
>  
> +	if (pdev->dev.of_node && of_property_read_u32(pdev->dev.of_node,
> +						      "dma-channel-mask",
> +						      &cqdma->dma_mask)) {

I'd prefer:

if (pdev->dev.of_node)
    ret = of_property_read_u32(pdev->dev.of_node,
                               "dma-channel-mask",
                               &cqdma->dma_mask))
if (ret) {
    dev_warn(&pdev->dev,
             "Using 0 as missing dma-channel-mask
              property\n");
    cqdma->dma_mask = 0;
}

> +		dev_info(&pdev->dev,
> +			 "Using 0 as missing dma-channel-mask property\n");

dev_warn should be OK.

> +	} else {
> +		cqdma_dmamask = DMA_BIT_MASK(cqdma->dma_mask);
> +		pdev->dev.dma_mask = &cqdma_dmamask;

if (dma_set_mask(&pdev->dev,
    DMA_BIT_MASK(cqdma->dma_mask)) {
         /* error out */
}

> +	}
> +
>  	cqdma->pc = devm_kcalloc(&pdev->dev, cqdma->dma_channels,
>  				 sizeof(*cqdma->pc), GFP_KERNEL);
>  	if (!cqdma->pc)
>