FROMLIST: dts: bindings: Document device tree bindings for Arm TRBE

Document the device tree bindings for Trace Buffer Extension (TRBE).

Bug: 174685394
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/linux-arm-kernel/20210225193543.2920532-20-suzuki.poulose@arm.com/
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Change-Id: I72dc33a185649809622273dd67ae227b11e8faaf

Documentation/devicetree/bindings/arm/trbe.yaml

@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
+# Copyright 2021, Arm Ltd
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/trbe.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: ARM Trace Buffer Extensions
+
+maintainers:
+  - Anshuman Khandual <anshuman.khandual@arm.com>
+
+description: |
+  Arm Trace Buffer Extension (TRBE) is a per CPU component
+  for storing trace generated on the CPU to memory. It is
+  accessed via CPU system registers. The software can verify
+  if it is permitted to use the component by checking the
+  TRBIDR register.
+
+properties:
+  $nodename:
+    const: "trbe"
+  compatible:
+    items:
+      - const: arm,trace-buffer-extension
+
+  interrupts:
+    description: |
+       Exactly 1 PPI must be listed. For heterogeneous systems where
+       TRBE is only supported on a subset of the CPUs, please consult
+       the arm,gic-v3 binding for details on describing a PPI partition.
+    maxItems: 1
+
+required:
+  - compatible
+  - interrupts
+
+additionalProperties: false
+
+examples:
+
+  - |
+   #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+   trbe {
+     compatible = "arm,trace-buffer-extension";
+     interrupts = <GIC_PPI 15 IRQ_TYPE_LEVEL_HIGH>;
+   };
+...