Re: [PATCH 1/6] dt-bindings: PCI: qcom-ep: describe optional IOMMU

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Feb 17, 2025 at 08:56:13PM +0200, Dmitry Baryshkov wrote:
> Platforms which use eDMA for PCIe EP transfers (like SA8775P) also use
> IOMMU in order to setup transfer windows.

eDMA has nothing to do with IOMMU. In fact, it is not clear on what IOMMU does
on the endpoint side since we do not assign SID based on the RID from RC.

But the binding should describe it anyway since IOMMU does sit between DDR and
PCIe IP.

- Mani

> Fix the schema in order to
> allow specifying the IOMMU.
> 
> Fixes: 9d3d5e75f31c ("dt-bindings: PCI: qcom-ep: Add support for SA8775P SoC")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> ---
>  Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml b/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> index 1226ee5d08d1ae909b07b0d78014618c4c74e9a8..800accdf5947e7178ad80f0759cf53111be1a814 100644
> --- a/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> +++ b/Documentation/devicetree/bindings/pci/qcom,pcie-ep.yaml
> @@ -75,6 +75,9 @@ properties:
>        - const: doorbell
>        - const: dma
>  
> +  iommus:
> +    maxItems: 1
> +
>    reset-gpios:
>      description: GPIO used as PERST# input signal
>      maxItems: 1
> @@ -233,6 +236,20 @@ allOf:
>            minItems: 3
>            maxItems: 3
>  
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: qcom,sdx55-pcie-ep
> +    then:
> +      properties:
> +        iommus:
> +          false
> +
> +    else:
> +      required:
> +        - iommus
> +
>  unevaluatedProperties: false
>  
>  examples:
> 
> -- 
> 2.39.5
> 

-- 
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