Re: [PATCH V3 4/6] dt-bindings: dma: xlnx,zynqmp-dma: Add Versal Net compatible support

On Mon, Aug 10, 2026 at 03:34:50PM +0530, Golla Nagendra wrote:
> From: Jay Buddhabhatti <[email protected]>
>
> Introduce a new compatible string amd,versal-net-dma-1.0 for
> Versal Net ZDMA.The new compatible requires xlnx,zynqmp-dma-1.0 as a
> fallback.
>
> Add a reset property to describe the per-channel reset line exposed
> on Versal Gen2 and Versal Net.

why only one reset if per-channel reset line?

> Mark the resets property as required
> for both Versal Gen2 and Versal Net, and not applicable for other
> platforms.
>
> Note that making resets required for Versal Gen2 results in an ABI
> break but this is unavoidable. When DMA is used by two software components
> back to back (e.g., firmware before Linux boot), DMA functionality fails
> due to configuration differences or the DMA being left in a bad state by
> the previous user. The channel can only be cleanly re-configured after
> a DMA channel reset,making it essential.
>
> Signed-off-by: Jay Buddhabhatti <[email protected]>
> Co-developed-by: Golla Nagendra <[email protected]>
> Signed-off-by: Golla Nagendra <[email protected]>
> ---
> Changes in V3:
> - Use allOf:if:then: to restrict the resets property per-compatible,
>   making it required for amd,versal2-dma-1.0 and amd,versal-net-dma-1.0
>   and explicitly setting resets: false for all other platforms
> - Add amd,versal-net-dma-1.0 compatible string with xlnx,zynqmp-dma-1.0
>   as fallback
> - Switch compatible from enum to oneOf to accommodate the new multi-item
>   entry for Versal Net
> - Add ABI break justification
> ---
>  .../dma/xilinx/xlnx,zynqmp-dma-1.0.yaml       | 25 ++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dma-1.0.yaml b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dma-1.0.yaml
> index 2da86037ad79..87c65aef5c7d 100644
> --- a/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dma-1.0.yaml
> +++ b/Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dma-1.0.yaml
> @@ -18,15 +18,31 @@ maintainers:
>
>  allOf:
>    - $ref: ../dma-controller.yaml#
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - amd,versal2-dma-1.0
> +              - amd,versal-net-dma-1.0
> +    then:
> +      required:
> +        - resets
> +    else:
> +      properties:
> +        resets: false
>
>  properties:
>    "#dma-cells":
>      const: 1
>
>    compatible:
> -    enum:
> -      - amd,versal2-dma-1.0
> -      - xlnx,zynqmp-dma-1.0
> +    oneOf:
> +      - const: amd,versal2-dma-1.0
> +      - const: xlnx,zynqmp-dma-1.0

         use enum
	 - enum
             - amd,versal2-dma-1.0
             - xlnx,zynqmp-dma-1.0

> +      - items:
> +          - const: amd,versal-net-dma-1.0
> +          - const: xlnx,zynqmp-dma-1.0
>
>    reg:
>      description: memory map for gdma/adma module access
> @@ -59,6 +75,9 @@ properties:
>    power-domains:
>      maxItems: 1
>
> +  resets:
> +    maxItems: 1
> +
>    dma-coherent: true
>
>  required:
> --
> 2.43.7
>