dt-bindings: cache: Add docs for StarFive Starlink cache controller

Add DT binding documentation used by StarFive's
Starlink cache controller.
Signed-off-by: Joshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Documentation/devicetree/bindings/cache/starfive,jh8100-starlink-cache.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/cache/starfive,jh8100-starlink-cache.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive StarLink Cache Controller
+
+maintainers:
+  - Joshua Yeong <joshua.yeong@starfivetech.com>
+
+description:
+  StarFive's StarLink Cache Controller manages the L3 cache shared between
+  clusters of CPU cores. The cache driver enables RISC-V non-standard cache
+  management as an alternative to instructions in the RISC-V Zicbom extension.
+
+allOf:
+  - $ref: /schemas/cache-controller.yaml#
+
+# We need a select here so we don't match all nodes with 'cache'
+select:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - starfive,jh8100-starlink-cache
+
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - const: starfive,jh8100-starlink-cache
+      - const: cache
+
+  reg:
+    maxItems: 1
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - cache-block-size
+  - cache-level
+  - cache-sets
+  - cache-size
+  - cache-unified
+
+examples:
+  - |
+      soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        cache-controller@15000000 {
+          compatible = "starfive,jh8100-starlink-cache", "cache";
+          reg = <0x0 0x15000000 0x0 0x278>;
+          cache-block-size = <64>;
+          cache-level = <3>;
+          cache-sets = <8192>;
+          cache-size = <0x400000>;
+          cache-unified;
+        };
+      };