[PATCH V4 2/3] dt-bindings: iommu: Add NVIDIA Tegra CMDQV support

[Ashish Mhetre <amhetre@nvidia.com>]

The Command Queue Virtualization (CMDQV) hardware is part of the
SMMUv3 implementation on NVIDIA Tegra SoCs. It assists in
virtualizing the command queue for the SMMU.

Add a new device tree binding document for nvidia,tegra264-cmdqv.

Also update the arm,smmu-v3 binding to include an optional nvidia,cmdqv
property. This property is a phandle to the CMDQV device node, allowing
the SMMU driver to associate with its corresponding CMDQV instance.
Restrict this property usage to Nvidia Tegra264 only.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Ashish Mhetre <amhetre@nvidia.com>
---
 .../bindings/iommu/arm,smmu-v3.yaml           | 30 ++++++++++++-
 .../bindings/iommu/nvidia,tegra264-cmdqv.yaml | 42 +++++++++++++++++++
 2 files changed, 70 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/iommu/nvidia,tegra264-cmdqv.yaml

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
index 75fcf4cb52d9..1c03482e4c61 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu-v3.yaml
@@ -20,7 +20,12 @@ properties:
   $nodename:
     pattern: "^iommu@[0-9a-f]*"
   compatible:
-    const: arm,smmu-v3
+    oneOf:
+      - const: arm,smmu-v3
+      - items:
+          - enum:
+              - nvidia,tegra264-smmu
+          - const: arm,smmu-v3
 
   reg:
     maxItems: 1
@@ -58,6 +63,15 @@ properties:
 
   msi-parent: true
 
+  nvidia,cmdqv:
+    description: |
+      A phandle to its pairing CMDQV extension for an implementation on NVIDIA
+      Tegra SoC.
+
+      If this property is absent, CMDQ-Virtualization won't be used and SMMU
+      will only use its own CMDQ.
+    $ref: /schemas/types.yaml#/definitions/phandle
+
   hisilicon,broken-prefetch-cmd:
     type: boolean
     description: Avoid sending CMD_PREFETCH_* commands to the SMMU.
@@ -69,6 +83,17 @@ properties:
       register access with page 0 offsets. Set for Cavium ThunderX2 silicon that
       doesn't support SMMU page1 register space.
 
+allOf:
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              const: nvidia,tegra264-smmu
+    then:
+      properties:
+        nvidia,cmdqv: false
+
 required:
   - compatible
   - reg
@@ -82,7 +107,7 @@ examples:
     #include <dt-bindings/interrupt-controller/irq.h>
 
     iommu@2b400000 {
-            compatible = "arm,smmu-v3";
+            compatible = "nvidia,tegra264-smmu", "arm,smmu-v3";
             reg = <0x2b400000 0x20000>;
             interrupts = <GIC_SPI 74 IRQ_TYPE_EDGE_RISING>,
                          <GIC_SPI 75 IRQ_TYPE_EDGE_RISING>,
@@ -92,4 +117,5 @@ examples:
             dma-coherent;
             #iommu-cells = <1>;
             msi-parent = <&its 0xff0000>;
+            nvidia,cmdqv = <&cmdqv>;
     };
diff --git a/Documentation/devicetree/bindings/iommu/nvidia,tegra264-cmdqv.yaml b/Documentation/devicetree/bindings/iommu/nvidia,tegra264-cmdqv.yaml
new file mode 100644
index 000000000000..3f5006a59805
--- /dev/null
+++ b/Documentation/devicetree/bindings/iommu/nvidia,tegra264-cmdqv.yaml
@@ -0,0 +1,42 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iommu/nvidia,tegra264-cmdqv.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NVIDIA Tegra264 CMDQV
+
+description:
+  The CMDQ-Virtualization hardware block is part of the SMMUv3 implementation
+  on Tegra264 SoCs. It assists in virtualizing the command queue for the SMMU.
+
+maintainers:
+  - Nicolin Chen <nicolinc@nvidia.com>
+
+properties:
+  compatible:
+    const: nvidia,tegra264-cmdqv
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    cmdqv@5200000 {
+            compatible = "nvidia,tegra264-cmdqv";
+            reg = <0x5200000 0x830000>;
+            interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
+    };
-- 
2.25.1