On 2020-06-30 01:10, Krishna Reddy wrote:
Add binding for NVIDIA's Tegra194 SoC SMMU topology that is based
on ARM MMU-500.

Signed-off-by: Krishna Reddy <vdu...@nvidia.com>
  Documentation/devicetree/bindings/iommu/arm,smmu.yaml | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml 
index d7ceb4c34423b..5b2586ac715ed 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.yaml
@@ -38,6 +38,11 @@ properties:
                - qcom,sc7180-smmu-500
                - qcom,sdm845-smmu-500
            - const: arm,mmu-500
+      - description: NVIDIA SoCs that use more than one "arm,mmu-500"

Hmm, there must be a better way to word that to express that it only applies to the sets of SMMUs that must be programmed identically, and not any other independent MMU-500s that might also happen to be in the same SoC.

+        items:
+          - enum:
+              - nvdia,tegra194-smmu
+          - const: arm,mmu-500

Is the fallback compatible appropriate here? If software treats this as a standard MMU-500 it will only program the first instance (because the second isn't presented as a separate MMU-500) - is there any way that isn't going to blow up?


        - items:
            - const: arm,mmu-500
            - const: arm,smmu-v2

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