dt-bindings: interrupt-controller: Add Xilinx Versal NET SMMU CSR

Add a device tree binding schema for the Xilinx Versal NET SMMU CSR
(Control and Status Register) interrupt controller.

The SMMU CSR block acts as a vendor-specific interrupt controller
in front of the ARM SMMUv3, providing registers to enable and clear
standard SMMU interrupts such as EVENTQ, CMDQ_SYNC, GERROR and PRIQ.
Interrupts must be acknowledged in this block before being forwarded
to the parent interrupt controller (e.g. GIC).

Co-developed-by: Tushar Nimkar <tushar.nimkar@amd.com>
Signed-off-by: Anirudha Sarangi <anirudha.sarangi@amd.com>
Signed-off-by: Tushar Nimkar <tushar.nimkar@amd.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260928-smmu-changes-v2-v4-1-3c79a14cd806@amd.com

Documentation/devicetree/bindings/interrupt-controller/xlnx,versal-net-smmu-csr.yaml

@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/xlnx,versal-net-smmu-csr.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx Versal NET SMMU CSR Interrupt Controller
+
+maintainers:
+  - Anirudha Sarangi <anirudha.sarangi@amd.com>
+  - Tushar Nimkar <tushar.nimkar@amd.com>
+
+description: |
+  The Versal NET platform includes a Xilinx-specific SMMU CSR (Control and
+  Status Register) block that acts as an intermediate interrupt controller
+  for ARM SMMUv3.
+
+  The block provides registers to enable, disable and clear the
+  standard SMMUv3 interrupt sources (EVENTQ, CMDQ_SYNC, GERROR and PRIQ)
+  before forwarding them to the parent interrupt controller,
+  typically a GIC.
+
+  The controller receives one parent interrupt and demultiplexes CSR
+  status bits into the following child interrupt identifiers
+    0 - EVENTQ
+    1 - CMDQ_SYNC
+    2 - GERROR (GLOBAL)
+    3 - PRIQ
+
+allOf:
+  - $ref: /schemas/interrupt-controller.yaml#
+
+properties:
+  compatible:
+    const: xlnx,versal-net-smmu-csr
+
+  reg:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+    description: |
+     Single cell containing the child interrupt identifier
+      0 - EVENTQ
+      1 - CMDQ_SYNC
+      2 - GERROR (GLOBAL)
+      3 - PRIQ
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupt-controller
+  - "#interrupt-cells"
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    interrupt-controller@eca10000 {
+        compatible = "xlnx,versal-net-smmu-csr";
+        reg = <0xeca10000 0x1000>;
+        interrupt-controller;
+        #interrupt-cells = <1>;
+        interrupt-parent = <&gic>;
+        interrupts = <GIC_SPI 169 IRQ_TYPE_LEVEL_HIGH>;
+    };