[PATCH v2 1/8] dt-bindings: arm-smmu: Add Adreno GPU variant

[PATCH v2 1/8] dt-bindings: arm-smmu: Add Adreno GPU variant

[Jordan Crouse]

Add a compatible string to identify SMMUs that are attached
to Adreno GPU devices that wish to support split pagetables.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
index 6515dbe..db9f826 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
@@ -31,6 +31,12 @@ properties:
               - qcom,sdm845-smmu-v2
           - const: qcom,smmu-v2
 
+      - description: Qcom Adreno GPU SMMU iplementing split pagetables
+        items:
+          - enum:
+              - qcom,adreno-smmu-v2
+          - const: qcom,smmu-v2
+
       - description: Qcom SoCs implementing "arm,mmu-500"
         items:
           - enum:
-- 
2.7.4

Re: [PATCH v2 1/8] dt-bindings: arm-smmu: Add Adreno GPU variant

[Rob Herring]

On Fri, Nov 22, 2019 at 11:31:51PM +0000, Jordan Crouse wrote:
> Add a compatible string to identify SMMUs that are attached
> to Adreno GPU devices that wish to support split pagetables.
> 
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
> 
>  Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v2 8/8] arm64: dts: qcom: sdm845: Update Adreno GPU SMMU compatible string

[Jordan Crouse]

Add "qcom,adreno-smmu-v2" compatible string for the Adreno GPU SMMU node
to enable split pagetable support.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

 arch/arm64/boot/dts/qcom/sdm845.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index ddb1f23..d90ba6eda 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -2869,7 +2869,7 @@
 		};
 
 		adreno_smmu: iommu@5040000 {
-			compatible = "qcom,sdm845-smmu-v2", "qcom,smmu-v2";
+			compatible = "qcom,adreno-smmu-v2", "qcom,smmu-v2";
 			reg = <0 0x5040000 0 0x10000>;
 			#iommu-cells = <1>;
 			#global-interrupts = <2>;
-- 
2.7.4

Re: [PATCH v2 1/8] dt-bindings: arm-smmu: Add Adreno GPU variant

[Robin Murphy]

On 22/11/2019 11:31 pm, Jordan Crouse wrote:
> Add a compatible string to identify SMMUs that are attached
> to Adreno GPU devices that wish to support split pagetables.

A software policy decision is not, in itself, a good justification for a 
DT property. Is the GPU SMMU fundamentally different in hardware* from 
the other SMMU(s) in any given SoC?

(* where "hardware" may encompass hypervisor shenanigans)

> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
> 
>   Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> index 6515dbe..db9f826 100644
> --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> @@ -31,6 +31,12 @@ properties:
>                 - qcom,sdm845-smmu-v2
>             - const: qcom,smmu-v2
>   
> +      - description: Qcom Adreno GPU SMMU iplementing split pagetables
> +        items:
> +          - enum:
> +              - qcom,adreno-smmu-v2
> +          - const: qcom,smmu-v2

Given that we already have per-SoC compatibles for Qcom SMMUs in 
general, this seems suspiciously vague.

Robin.

> +
>         - description: Qcom SoCs implementing "arm,mmu-500"
>           items:
>             - enum:
> 

Re: [PATCH v2 1/8] dt-bindings: arm-smmu: Add Adreno GPU variant

[Rob Clark]

On Wed, Dec 4, 2019 at 7:56 AM Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 22/11/2019 11:31 pm, Jordan Crouse wrote:
> > Add a compatible string to identify SMMUs that are attached
> > to Adreno GPU devices that wish to support split pagetables.
>
> A software policy decision is not, in itself, a good justification for a
> DT property. Is the GPU SMMU fundamentally different in hardware* from
> the other SMMU(s) in any given SoC?

The GPU CP has some sort of mechanism to switch pagetables.. although
I guess under the firmware it is all the same.  Jordan should know
better..

BR,
-R

> (* where "hardware" may encompass hypervisor shenanigans)
>
> > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> > ---
> >
> >   Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > index 6515dbe..db9f826 100644
> > --- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > +++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
> > @@ -31,6 +31,12 @@ properties:
> >                 - qcom,sdm845-smmu-v2
> >             - const: qcom,smmu-v2
> >
> > +      - description: Qcom Adreno GPU SMMU iplementing split pagetables
> > +        items:
> > +          - enum:
> > +              - qcom,adreno-smmu-v2
> > +          - const: qcom,smmu-v2
>
> Given that we already have per-SoC compatibles for Qcom SMMUs in
> general, this seems suspiciously vague.
>
> Robin.
>
> > +
> >         - description: Qcom SoCs implementing "arm,mmu-500"
> >           items:
> >             - enum:
> >
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