Re: [PATCH v2 1/6] dt-bindings: iommu: arm,smmu: Document interconnects property

[Bibek Kumar Patro]

On 6/8/2026 3:22 PM, Konrad Dybcio wrote:
> On 5/26/26 4:42 PM, Bibek Kumar Patro wrote:
> > Some SoC implementations require a bandwidth vote on an interconnect
> > path before the SMMU register space is accessible. Add the optional
> > 'interconnects' property to the binding to allow platform DT nodes
> > to describe this path.
> >
> > Signed-off-by: Bibek Kumar Patro <bibek.patro@xxxxxxxxxxxxxxxx>
> > ---
> >   .../devicetree/bindings/iommu/arm,smmu.yaml        | 27 ++++++++++++++++++++++
> >   1 file changed, 27 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > index 06fb5c8e7547cb7a92823adc2772b94f747376a6..3a677ff1a18fcdf5c0ca9ec8a017d41f9eb5ff09 100644
> > --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > @@ -243,6 +243,13 @@ properties:
> >       minItems: 1
> >       maxItems: 3
> >   
> > +  interconnects:
> > +    maxItems: 1
> > +    description:
> > +      Interconnect path to the SMMU register space. Required on SoCs
> > +      where the SMMU registers are only accessible after a bandwidth
> > +      vote has been placed on the interconnect fabric.
> > +
> >     nvidia,memory-controller:
> >       description: |
> >         A phandle to the memory controller on NVIDIA Tegra186 and later SoCs.
> > @@ -602,6 +609,26 @@ allOf:
> >           clock-names: false
> >           clocks: false
> >   
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          items:
> > +            - enum:
> > +                - qcom,qcs615-smmu-500
> > +                - qcom,qcs8300-smmu-500
> > +                - qcom,sa8775p-smmu-500
> > +                - qcom,sc7280-smmu-500
>
> This is a list of targets that happen to be supported by QLI.. but should
> this list not contain _all_ Qualcomm SoCs, or at least a much broader range?
>
> Perhaps
>
> if: properties: compatible: contains: qcom,adreno-smmu
>
> ?

As of now platforms where the issues [1] getting reported are added, the
list will grow.
<We still have to evaluate and test on other non-QLI platforms hosted in
upstream [2]>

[1]: https://github.com/qualcomm-linux/kernel/issues/297
[2]: 
https://lore.kernel.org/all/a437f9f9-3560-40f8-85ea-35433e33c428@xxxxxxxxxxxxxxxx/

> Konrad