[PATCH 6/9] dt-bindings: Add RISC-V advanced PLIC bindings

[Anup Patel]

We add DT bindings document for RISC-V advanced platform level interrupt
controller (APLIC) defined by the RISC-V advanced interrupt architecture
(AIA) specification.

Signed-off-by: Anup Patel <apatel at ventanamicro.com>
---
 .../interrupt-controller/riscv,aplic.yaml     | 136 ++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml

diff --git a/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml b/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
new file mode 100644
index 000000000000..0aa48571f3bc
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/riscv,aplic.yaml
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/riscv,aplic.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V Advancded Platform Level Interrupt Controller (APLIC)
+
+maintainers:
+  - Anup Patel <anup at brainfault.org>
+
+description:
+  The RISC-V advanced interrupt architecture (AIA) defines advanced platform
+  level interrupt controller (APLIC) for handling wired interrupts in a
+  RISC-V platform. The RISC-V AIA specification can be found at
+  https://github.com/riscv/riscv-aia.
+
+  The RISC-V APLIC is implemented as hierarchical APLIC domains where all
+  interrupt sources connect to the root domain which can further delegate
+  interrupts to child domains. We have one device tree node for each APLIC
+  domain.
+
+allOf:
+  - $ref: /schemas/interrupt-controller.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - vendor,chip-aplic
+      - const: riscv,aplic
+
+  reg:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 2
+
+  interrupts-extended:
+    minItems: 1
+    maxItems: 16384
+    description:
+      The presence of this property implies that given APLIC domain directly
+      injects external interrupts to a set of RISC-V HARTS (or CPUs). Each
+      node pointed to should be a riscv,cpu-intc node, which has a riscv node
+      (i.e. RISC-V HART) as parent.
+
+  msi-parent:
+    description:
+      The presence of this property implies that given APLIC domain forwards
+      wired interrupts as MSIs to a AIA incoming message signaled interrupt
+      controller (IMSIC). This property should be considered only when the
+      interrupts-extended property is absent.
+
+  riscv,num-sources:
+    $ref: "/schemas/types.yaml#/definitions/uint32"
+    minimum: 1
+    maximum: 1023
+    description:
+      Specifies how many wired interrupts are supported by this APLIC domain.
+
+  riscv,children:
+    $ref: '/schemas/types.yaml#/definitions/phandle-array'
+    minItems: 1
+    maxItems: 1024
+    description:
+      This property represents a list of child APLIC domains for the given
+      APLIC domain. Each child APLIC domain is assigned child index in
+      increasing order with the first child APLIC domain assigned child
+      index 0. The APLIC domain child index is used by firmware to delegate
+      interrupts from the given APLIC domain to a particular child APLIC
+      domain.
+
+  riscv,delegate:
+    $ref: '/schemas/types.yaml#/definitions/phandle-array'
+    minItems: 1
+    maxItems: 1024
+    description:
+      This property represents a interrupt delegation list where each entry
+      is a triple consisting of child APLIC domain phandle, first interrupt
+      number, and last interrupt number. The firmware will configure interrupt
+      delegation registers based on interrupt delegation list.
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupt-controller
+  - "#interrupt-cells"
+  - riscv,num-sources
+
+examples:
+  - |
+    // Example 1 (APIC domain directly injecting interrupt to HARTs):
+
+    aplic0: interrupt-controller at c000000 {
+      compatible = "vendor,chip-aplic", "riscv,aplic";
+      interrupts-extended = <&cpu1_intc 11>,
+                            <&cpu2_intc 11>,
+                            <&cpu3_intc 11>,
+                            <&cpu4_intc 11>;
+      reg = <0xc000000 0x4080>;
+      interrupt-controller;
+      #interrupt-cells = <2>;
+      riscv,num-sources = <63>;
+      riscv,children = <&aplic1>;
+      riscv,delegate = <&aplic1 1 63>;
+    };
+
+    aplic1: interrupt-controller at d000000 {
+      compatible = "vendor,chip-aplic", "riscv,aplic";
+      interrupts-extended = <&cpu1_intc 9>,
+                            <&cpu2_intc 9>,
+                            <&cpu3_intc 9>,
+                            <&cpu4_intc 9>;
+      reg = <0xd000000 0x4080>;
+      interrupt-controller;
+      #interrupt-cells = <2>;
+      riscv,num-sources = <63>;
+    };
+
+  - |
+    // Example 2 (APIC domain forwarding interrupts as MSIs):
+
+    interrupt-controller at d000000 {
+      compatible = "vendor,chip-aplic", "riscv,aplic";
+      msi-parent = <&imsics>;
+      reg = <0xd000000 0x4000>;
+      interrupt-controller;
+      #interrupt-cells = <2>;
+      riscv,num-sources = <63>;
+    };
+...
-- 
2.34.1