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

Anshuman Khandual
2021-01-27T08:57:30Z

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