dts: bindings: Document device tree bindings for ETE

# 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:

    description: |

      Output connections from the ETE to legacy CoreSight trace bus.

    $ref: /schemas/graph.yaml#/properties/ports

    properties:

      port:

        description: Output connection from the ETE to legacy CoreSight Trace bus.

        $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>;

             };

         };

      };

   };

...

F:	Documentation/devicetree/bindings/arm/coresight-cpu-debug.txt

F:	Documentation/devicetree/bindings/arm/coresight-cti.yaml

F:	Documentation/devicetree/bindings/arm/coresight.txt

F:	Documentation/devicetree/bindings/arm/ete.yaml

F:	Documentation/trace/coresight/*

F:	drivers/hwtracing/coresight/*

F:	include/dt-bindings/arm/coresight-cti-dt.h