[PATCH V3 06/14] dts: bindings: Document device tree bindings for ETE

From: Anshuman Khandual <anshuman.khandual@arm.com>
To: linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org
Cc: mathieu.poirier@linaro.org, suzuki.poulose@arm.com,
	mike.leach@linaro.org, lcherian@marvell.com,
	linux-kernel@vger.kernel.org,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	devicetree@vger.kernel.org, Rob Herring <robh@kernel.org>
Subject: [PATCH V3 06/14] dts: bindings: Document device tree bindings for ETE
Date: Wed, 27 Jan 2021 14:25:30 +0530	[thread overview]
Message-ID: <1611737738-1493-7-git-send-email-anshuman.khandual@arm.com> (raw)
In-Reply-To: <1611737738-1493-1-git-send-email-anshuman.khandual@arm.com>

From: Suzuki K Poulose <suzuki.poulose@arm.com>

Document the device tree bindings for Embedded Trace Extensions.
ETE can be connected to legacy coresight components and thus
could optionally contain a connection graph as described by
the CoreSight bindings.

Cc: devicetree@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
---
Changes in V3:

- Fixed all DT yaml semantics problems

 Documentation/devicetree/bindings/arm/ete.yaml | 74 ++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/arm/ete.yaml

diff --git a/Documentation/devicetree/bindings/arm/ete.yaml b/Documentation/devicetree/bindings/arm/ete.yaml
new file mode 100644
index 0000000..edc1fe2
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/ete.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
+# Copyright 2021, Arm Ltd
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/ete.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: ARM Embedded Trace Extensions
+
+maintainers:
+  - Suzuki K Poulose <suzuki.poulose@arm.com>
+  - Mathieu Poirier <mathieu.poirier@linaro.org>
+
+description: |
+  Arm Embedded Trace Extension(ETE) is a per CPU trace component that
+  allows tracing the CPU execution. It overlaps with the CoreSight ETMv4
+  architecture and has extended support for future architecture changes.
+  The trace generated by the ETE could be stored via legacy CoreSight
+  components (e.g, TMC-ETR) or other means (e.g, using a per CPU buffer
+  Arm Trace Buffer Extension (TRBE)). Since the ETE can be connected to
+  legacy CoreSight components, a node must be listed per instance, along
+  with any optional connection graph as per the coresight bindings.
+  See bindings/arm/coresight.txt.
+
+properties:
+  $nodename:
+    pattern: "^ete([0-9a-f]+)$"
+  compatible:
+    items:
+      - const: arm,embedded-trace-extension
+
+  cpu:
+    description: |
+      Handle to the cpu this ETE is bound to.
+    $ref: /schemas/types.yaml#/definitions/phandle
+
+  out-ports:
+    type: object
+    description: |
+      Output connections from the ETE to legacy CoreSight trace bus.
+    properties:
+      port:
+        $ref: /schemas/graph.yaml#/properties/port
+
+required:
+  - compatible
+  - cpu
+
+additionalProperties: false
+
+examples:
+
+# An ETE node without legacy CoreSight connections
+  - |
+    ete0 {
+      compatible = "arm,embedded-trace-extension";
+      cpu = <&cpu_0>;
+    };
+# An ETE node with legacy CoreSight connections
+  - |
+   ete1 {
+      compatible = "arm,embedded-trace-extension";
+      cpu = <&cpu_1>;
+
+      out-ports {        /* legacy coresight connection */
+         port {
+             ete1_out_port: endpoint {
+                remote-endpoint = <&funnel_in_port0>;
+             };
+         };
+      };
+   };
+
+...
-- 
2.7.4

