Re: [PATCH RFC 2/3] dmaengine: dma-axi-dmac: Switch to bitmap-based address width masks

[Frank Li <Frank.li@oss.nxp.com>]

On Tue, Jun 16, 2026 at 04:40:53PM +0100, Nuno Sá via B4 Relay wrote:
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>
> From: Nuno Sá <nuno.sa@analog.com>
>
> Advertise the source and destination bus widths through the new
> dma_set_{src,dst}_addr_mask() helpers instead of open-coding the legacy
> BIT() mask. This moves the driver onto the representation that can
> express widths of 32 bytes and above and allows the legacy u32 field to
> be removed once all users are converted.
>
> While at it, give the channel width members their proper
> enum dma_slave_buswidth type.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> ---
>  drivers/dma/dma-axi-dmac.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
> index d47ff27e1408..19c258d511ca 100644
> --- a/drivers/dma/dma-axi-dmac.c
> +++ b/drivers/dma/dma-axi-dmac.c
> @@ -152,8 +152,8 @@ struct axi_dmac_chan {
>         struct list_head active_descs;
>         enum dma_transfer_direction direction;
>
> -       unsigned int src_width;
> -       unsigned int dest_width;
> +       enum dma_slave_buswidth src_width;
> +       enum dma_slave_buswidth dest_width;
>         unsigned int src_type;
>         unsigned int dest_type;
>
> @@ -1262,8 +1262,12 @@ static int axi_dmac_probe(struct platform_device *pdev)
>         dma_dev->device_terminate_all = axi_dmac_terminate_all;
>         dma_dev->device_synchronize = axi_dmac_synchronize;
>         dma_dev->dev = &pdev->dev;
> -       dma_dev->src_addr_widths = BIT(dmac->chan.src_width);
> -       dma_dev->dst_addr_widths = BIT(dmac->chan.dest_width);
> +       ret = dma_set_src_addr_mask(dma_dev, &dmac->chan.src_width, 1);
> +       if (ret)
> +               return ret;
> +       ret = dma_set_dst_addr_mask(dma_dev, &dmac->chan.dest_width, 1);
> +       if (ret)
> +               return ret;


This patch is okay.  I think most system only set one width once, do we
really need pass down arrary.

Frank

>         dma_dev->directions = BIT(dmac->chan.direction);
>         dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
>         dma_dev->max_sg_burst = 31; /* 31 SGs maximum in one burst */
>
> --
> 2.54.0
>
>