Re: [PATCH 9/9] dmaengine: Drop legacy bus width fields from dma_slave_caps

On Thu, Jul 30, 2026 at 03:23:16PM +0100, Nuno Sá via B4 Relay wrote:
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>
> From: Nuno Sá <[email protected]>
>
> All users of dma_get_slave_caps() that inspect bus width capabilities
> now use bitmap helpers.
>
> Remove the legacy fields from struct dma_slave_caps and stop copying the
> dma_device legacy masks into them.
>
> Keep folding legacy dma_device masks into the returned bitmaps so
> unconverted DMA controller producers continue to work during the
> transition.

which one you kept?

Frank

>
> Signed-off-by: Nuno Sá <[email protected]>
> ---
>  drivers/dma/dmaengine.c   |  2 --
>  include/linux/dmaengine.h | 16 ++--------------
>  2 files changed, 2 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
> index 7be23ba769d0..ee0b8bfc7c97 100644
> --- a/drivers/dma/dmaengine.c
> +++ b/drivers/dma/dmaengine.c
> @@ -592,7 +592,6 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
>         if (!device->directions)
>                 return -ENXIO;
>
> -       caps->src_addr_widths = device->src_addr_widths;
>         if (bitmap_empty(device->src_bus_widths, DMA_SLAVE_BUSWIDTH_MAX)) {
>                 bitmap_zero(caps->src_bus_widths, DMA_SLAVE_BUSWIDTH_MAX);
>                 bitmap_from_arr32(caps->src_bus_widths,
> @@ -602,7 +601,6 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps)
>                             DMA_SLAVE_BUSWIDTH_MAX);
>         }
>
> -       caps->dst_addr_widths = device->dst_addr_widths;
>         if (bitmap_empty(device->dst_bus_widths, DMA_SLAVE_BUSWIDTH_MAX)) {
>                 bitmap_zero(caps->dst_bus_widths, DMA_SLAVE_BUSWIDTH_MAX);
>                 bitmap_from_arr32(caps->dst_bus_widths,
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index cea57b166dcb..f37a0559ec5f 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -495,9 +495,7 @@ enum dma_residue_granularity {
>   * @src_bus_widths: bitmap of source bus widths the channel supports.
>   *     Width is specified in bytes, e.g. for a channel supporting
>   *     a width of 4 the bitmap should have bit 4 set.
> - * @src_addr_widths: legacy bit mask of source bus widths the channel supports.
>   * @dst_bus_widths: bitmap of destination bus widths the channel supports.
> - * @dst_addr_widths: legacy bit mask of destination bus widths the channel supports.
>   * @directions: bit mask of slave directions the channel supports.
>   *     Since the enum dma_transfer_direction is not defined as bit flag for
>   *     each type, the dma controller should set BIT(<TYPE>) and same
> @@ -516,14 +514,8 @@ enum dma_residue_granularity {
>   * resubmitted multiple times
>   */
>  struct dma_slave_caps {
> -       struct {
> -               DECLARE_DMA_BUS_WIDTHS(src_bus_widths);
> -               u32 src_addr_widths;
> -       };
> -       struct {
> -               DECLARE_DMA_BUS_WIDTHS(dst_bus_widths);
> -               u32 dst_addr_widths;
> -       };
> +       DECLARE_DMA_BUS_WIDTHS(src_bus_widths);
> +       DECLARE_DMA_BUS_WIDTHS(dst_bus_widths);
>         u32 directions;
>         u32 min_burst;
>         u32 max_burst;
> @@ -1789,8 +1781,6 @@ dma_slave_caps_clear_src_width(struct dma_slave_caps *caps,
>                                enum dma_slave_buswidth width)
>  {
>         __clear_bit(width, caps->src_bus_widths);
> -       if (width < DMA_SLAVE_BUSWIDTH_32_BYTES)
> -               caps->src_addr_widths &= ~BIT(width);
>  }
>
>  /**
> @@ -1803,8 +1793,6 @@ dma_slave_caps_clear_dst_width(struct dma_slave_caps *caps,
>                                enum dma_slave_buswidth width)
>  {
>         __clear_bit(width, caps->dst_bus_widths);
> -       if (width < DMA_SLAVE_BUSWIDTH_32_BYTES)
> -               caps->dst_addr_widths &= ~BIT(width);
>  }
>
>  static inline int __dma_set_bus_widths(unsigned long *bus_widths,
>
> --
> 2.55.0
>
>