Re: [PATCH v2 2/5] dt-bindings: iommu: mediatek: Fix interrupt count constraint for new SoCs

[Macpaul Lin]

On 9/30/24 16:49, AngeloGioacchino Del Regno wrote:
> Il 26/09/24 13:14, Macpaul Lin ha scritto:
> > The infra-iommu node in mt8195.dtsi was triggering a CHECK_DTBS error due
> > to an excessively long 'interrupts' property. The error message was:

[snip]

> > diff --git 
> > a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml 
> > b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> > index ea6b0f5f24de..fdd2996d2a31 100644
> > --- a/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> > +++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.yaml
> > @@ -96,7 +96,8 @@ properties:
> >       maxItems: 1
> >     interrupts:
> > -    maxItems: 1
> > +    minItems: 1
> > +    maxItems: 5
> >     clocks:
> >       items:
> > @@ -210,6 +211,28 @@ allOf:
> >         required:
> >           - mediatek,larbs
> > +  - if:
> > +      properties:
> > +        compatible:
> > +          contains:
> > +            enum:
> > +              - mediatek,mt8195-iommu-infra
> > +
> > +    then:
> > +      properties:
> > +        interrupts:
> > +          description: |
>
> Do you really need to keep the formatting?
>
> If you rephrase that as:
>
> The infra IOMMU in MT8195 has five banks: each features one set
> of APB registers for the normal world (set 0), one

Shouldn't we use a 'three' here?
Three APB register sets for the protected world 1, protected world 2,
and protected world 3.

> for the protected
> world (sets 1-3) and one for the secure world (set 4), and each set
> has its own interrupt. Therefore, five interrupts are needed.
>
> ...you won't need the bar :-)

Thanks for the suggestion. The description has been moved to
top common property in v3, and v4,
hence the bar is still required to explain the
others SOCs. I'll try to rephrase the description for MT8195 also.

> > +            The IOMMU of MT8195 has 5 banks: 0/1/2/3/4.
> > +            Each bank has a set of APB registers corresponding to the
> > +            normal world, protected world 1/2/3, and secure world, 
> > respectively.
> > +            Therefore, 5 interrupt numbers are needed.
> > +          maxItems: 5
>
> minItems: 5
>
> Cheers,
> Angelo

Thanks
Macpaul Lin