Re: [PATCH v2 1/9] dt-bindings: arm-smmu: Allow up to 3 power-domains

[Konrad Dybcio]

On 14/11/2022 17:58, Krzysztof Kozlowski wrote:
> On 14/11/2022 16:53, Konrad Dybcio wrote:
> > On 14/11/2022 14:00, Krzysztof Kozlowski wrote:
> > > On 14/11/2022 12:17, Konrad Dybcio wrote:
> > > > On 14/11/2022 12:01, Krzysztof Kozlowski wrote:
> > > > > On 14/11/2022 11:42, Konrad Dybcio wrote:
> > > > > > Some SMMUs require that a vote is held on as much as 3 separate PDs
> > > > > > (hello Qualcomm). Allow it in bindings.
> > > > > >
> > > > > > Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> > > > > > ---
> > > > > > Changes since v1:
> > > > > > - Add minItems
> > > > > >
> > > > > >     Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 3 ++-
> > > > > >     1 file changed, 2 insertions(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > > > > > index 9066e6df1ba1..82bc696de662 100644
> > > > > > --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > > > > > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > > > > > @@ -159,7 +159,8 @@ properties:
> > > > > >               through the TCU's programming interface.
> > > > > >     
> > > > > >       power-domains:
> > > > > > -    maxItems: 1
> > > > > > +    minItems: 0
> > > > > It cannot be 0.
> > > > >
> > > > > minItems: 1
> > > > >
> > > > > Anyway you still need to restrict it per variant, as I said in previous
> > > > > version.
> > > > Hm.. I'm not entirely sure what you mean.. Should I add a list of
> > > > compatibles
> > > Yes and limit it to maxItems: 1 for "else".
> >
> > I tried adding:
> >
> >
> >
> >     - if:
> >         properties:
> >           compatible:
> >             contains:
> >               enum:
> >                 - qcom,sm6375-smmu-500
> >       then:
> >         properties:
> >           power-domains:
> >             minItems: 3
> >             maxItems: 3
> >       else:
> >         properties:
> >           power-domains:
> >             maxItems: 1
> >
> >
> > Right under the nvidia reg if-else in the allOf, but dtbs_check throws
> > errors like:
> >
> >
> > /home/konrad/linux/arch/arm64/boot/dts/qcom/msm8998-sony-xperia-yoshino-poplar.dtb:
> > iommu@5040000: 'power-domains' does not match any of the regexes:
> > 'pinctrl-[0-9]+'
> >
> >
> > Any clues as to why?
>
> I don't know what code do you have there, but generic pattern is:
>
> https://elixir.bootlin.com/linux/v5.19-rc6/source/Documentation/devicetree/bindings/clock/samsung,exynos7-clock.yaml#L38
I tried many things, but I still don't seem to get a hang of it.. Here's 
my current diff rebased on top of Dmitry's recent cleanups (available at 
[1])


diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml 
b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
index 28f5720824cd..55759aebc4a0 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
@@ -200,7 +200,7 @@ properties:
     maxItems: 7

   power-domains:
-    maxItems: 1
+    maxItems: 3

   nvidia,memory-controller:
     description: |
@@ -364,6 +364,26 @@ allOf:
             - description: interface clock required to access smmu's 
registers
                 through the TCU's programming interface.

+  - if:
+      properties:
+        compatible:
+          contains:
+            const: qcom,sm6375-smmu-500
+    then:
+      properties:
+        power-domains:
+          items:
+            - description: SNoC MMU TBU RT GDSC
+            - description: SNoC MMU TBU NRT GDSC
+            - description: SNoC TURING MMU TBU0 GDSC
+
+      required:
+        - power-domains
+    else:
+      properties:
+        power-domains:
+          maxItems: 1
+
 examples:
   - |+
     /* SMMU with stream matching or stream indexing */


In my eyes, this should work, but I still get errors like:

/home/konrad/linux/arch/arm64/boot/dts/qcom/sm8250-hdk.dtb: 
iommu@3da0000: power-domains: [[108, 0]] is too short

as if the else: path was never taken..

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=for-joerg/arm-smmu/bindings

Konrad
> Best regards,
> Krzysztof