dt-bindings: mips: Document mti,mips-cm

Add device tree binding documentation for MIPS Coherence Manager. This
component enables support for SMP by providing each processor in the
system with a uniform view of memory. The Coherence Manager is
responsible for establishing the global ordering of requests from all
elements of the system and sending the correct data back to the
requester.

Based on the work of Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

Documentation/devicetree/bindings/mips/mti,mips-cm.yaml

@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mips/mti,mips-cm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MIPS Coherence Manager
+
+description:
+  The Coherence Manager (CM) is responsible for establishing the
+  global ordering of requests from all elements of the system and
+  sending the correct data back to the requester. It supports Cache
+  to Cache transfers.
+  https://training.mips.com/cps_mips/PDF/CPS_Introduction.pdf
+  https://training.mips.com/cps_mips/PDF/Coherency_Manager.pdf
+
+maintainers:
+  - Jiaxun Yang <jiaxun.yang@flygoat.com>
+
+properties:
+  compatible:
+    const: mti,mips-cm
+
+  reg:
+    description:
+      Base address and size of the Global Configuration Registers
+      referred to as CMGCR.They are the system programmer's interface
+      to the Coherency Manager. Their location in the memory map is
+      determined at core build time. In a functional system, the base
+      address is provided by the Coprocessor 0, but some
+      System-on-Chip (SoC) designs may not provide an accurate address
+      that needs to be described statically.
+
+    maxItems: 1
+
+required:
+  - compatible
+
+additionalProperties: false
+
+examples:
+  - |
+    coherency-manager@1fbf8000 {
+      compatible = "mti,mips-cm";
+      reg = <0x1bde8000 0x8000>;
+    };
+...