Re: [PATCH v6 2/3] dt-bindings: arm: Add support for Coresight dummy trace

[Hao Zhang <quic_hazha@quicinc.com>]

Hi Reviewers,

Could you please help to review this patch?

Thanks
Hao

On 6/2/2023 4:41 PM, Hao Zhang wrote:
> This patch add support for Coresight dummy source and dummy sink trace.
> 
> Signed-off-by: Hao Zhang <quic_hazha@quicinc.com>
> ---
>   .../arm/arm,coresight-dummy-sink.yaml         | 73 +++++++++++++++++++
>   .../arm/arm,coresight-dummy-source.yaml       | 71 ++++++++++++++++++
>   2 files changed, 144 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/arm/arm,coresight-dummy-sink.yaml
>   create mode 100644 Documentation/devicetree/bindings/arm/arm,coresight-dummy-source.yaml
> 
> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-dummy-sink.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-dummy-sink.yaml
> new file mode 100644
> index 000000000000..cb78cfa56702
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-dummy-sink.yaml
> @@ -0,0 +1,73 @@
> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/arm/arm,coresight-dummy-sink.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ARM Coresight Dummy sink component
> +
> +description: |
> +  CoreSight components are compliant with the ARM CoreSight architecture
> +  specification and can be connected in various topologies to suit a particular
> +  SoCs tracing needs. These trace components can generally be classified as
> +  sinks, links and sources. Trace data produced by one or more sources flows
> +  through the intermediate links connecting the source to the currently selected
> +  sink.
> +
> +  The Coresight dummy sink component is for the specific coresight sink devices
> +  kernel don't have permission to access or configure, e.g., CoreSight EUD on
> +  Qualcomm platforms. It is a mini-USB hub implemented to support the USB-based
> +  debug and trace capabilities. For this device, a dummy driver is needed to
> +  register it as Coresight sink device in kernel side, so that path can be
> +  created in the driver. Then the trace flow would be transferred to EUD via
> +  coresight link of AP processor. It provides Coresight API for operations on
> +  dummy source devices, such as enabling and disabling them. It also provides
> +  the Coresight dummy source paths for debugging.
> +
> +  The primary use case of the coresight dummy sink is to build path in kernel
> +  side for dummy sink component.
> +
> +maintainers:
> +  - Mike Leach <mike.leach@linaro.org>
> +  - Suzuki K Poulose <suzuki.poulose@arm.com>
> +  - James Clark <james.clark@arm.com>
> +  - Mao Jinlong <quic_jinlmao@quicinc.com>
> +  - Hao Zhang <quic_hazha@quicinc.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - arm,coresight-dummy-sink
> +
> +  in-ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port:
> +        description: Input connection from the Coresight Trace bus to
> +          dummy sink, such as Embedded USB debugger(EUD).
> +
> +        $ref: /schemas/graph.yaml#/properties/port
> +
> +required:
> +  - compatible
> +  - in-ports
> +
> +additionalProperties: false
> +
> +examples:
> +  # Minimum dummy sink definition. Dummy sink connect to coresight replicator.
> +  - |
> +    sink {
> +      compatible = "arm,coresight-dummy-sink";
> +
> +      in-ports {
> +        port {
> +          eud_in_replicator_swao: endpoint {
> +            remote-endpoint = <&replicator_swao_out_eud>;
> +          };
> +        };
> +      };
> +    };
> +
> +...
> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-dummy-source.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-dummy-source.yaml
> new file mode 100644
> index 000000000000..5fedaed49a1f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-dummy-source.yaml
> @@ -0,0 +1,71 @@
> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/arm/arm,coresight-dummy-source.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ARM Coresight Dummy source component
> +
> +description: |
> +  CoreSight components are compliant with the ARM CoreSight architecture
> +  specification and can be connected in various topologies to suit a particular
> +  SoCs tracing needs. These trace components can generally be classified as
> +  sinks, links and sources. Trace data produced by one or more sources flows
> +  through the intermediate links connecting the source to the currently selected
> +  sink.
> +
> +  The Coresight dummy source component is for the specific coresight source
> +  devices kernel don't have permission to access or configure. For some SOCs,
> +  there would be Coresight source trace components on sub-processor which
> +  are conneted to AP processor via debug bus. For these devices, a dummy driver
> +  is needed to register them as Coresight source devices, so that paths can be
> +  created in the driver. It provides Coresight API for operations on dummy
> +  source devices, such as enabling and disabling them. It also provides the
> +  Coresight dummy source paths for debugging.
> +
> +  The primary use case of the coresight dummy source is to build path in kernel
> +  side for dummy source component.
> +
> +maintainers:
> +  - Mike Leach <mike.leach@linaro.org>
> +  - Suzuki K Poulose <suzuki.poulose@arm.com>
> +  - James Clark <james.clark@arm.com>
> +  - Mao Jinlong <quic_jinlmao@quicinc.com>
> +  - Hao Zhang <quic_hazha@quicinc.com>
> +
> +properties:
> +  compatible:
> +    enum:
> +      - arm,coresight-dummy-source
> +
> +  out-ports:
> +    $ref: /schemas/graph.yaml#/properties/ports
> +
> +    properties:
> +      port:
> +        description: Output connection from the source to Coresight
> +          Trace bus.
> +        $ref: /schemas/graph.yaml#/properties/port
> +
> +required:
> +  - compatible
> +  - out-ports
> +
> +additionalProperties: false
> +
> +examples:
> +  # Minimum dummy source definition. Dummy source connect to coresight funnel.
> +  - |
> +    source {
> +      compatible = "arm,coresight-dummy-source";
> +
> +      out-ports {
> +        port {
> +          dummy_riscv_out_funnel_swao: endpoint {
> +            remote-endpoint = <&funnel_swao_in_dummy_riscv>;
> +          };
> +        };
> +      };
> +    };
> +
> +...