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Message-ID: <3f0fcf17-f073-298f-7876-547e780ac600@quicinc.com>
Date:   Tue, 28 Mar 2023 19:29:48 +0800
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Subject: Re: [PATCH v2 2/3] dt-bindings: arm: Add Coresight Dummy Trace YAML
 schema
Content-Language: en-US
To:     Mike Leach <mike.leach@linaro.org>
CC:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Konrad Dybcio <konradybcio@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Jonathan Corbet <corbet@lwn.net>, Leo Yan <leo.yan@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        <coresight@lists.linaro.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <devicetree@vger.kernel.org>,
        Tingwei Zhang <quic_tingweiz@quicinc.com>,
        Jinlong Mao <quic_jinlmao@quicinc.com>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Tao Zhang <quic_taozha@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        <linux-arm-msm@vger.kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        <linux-doc@vger.kernel.org>
References: <20230324061608.33609-1-quic_hazha@quicinc.com>
 <20230324061608.33609-3-quic_hazha@quicinc.com>
 <e51c200e-6de0-d516-3f32-28367b2f5a95@linaro.org>
 <e6b0a542-17d9-290e-7c84-8356a38d6802@quicinc.com>
 <CAJ9a7VjC+1m8odyotBoG3EPAL=Cn90fCCY1xPGFyg8uKEar7nQ@mail.gmail.com>
From:   Hao Zhang <quic_hazha@quicinc.com>
In-Reply-To: <CAJ9a7VjC+1m8odyotBoG3EPAL=Cn90fCCY1xPGFyg8uKEar7nQ@mail.gmail.com>
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Hi Mike,

On 3/28/2023 6:12 PM, Mike Leach wrote:
> Hi,
> 
> As per my comments in the previous patch in this set....
> 
> On Mon, 27 Mar 2023 at 08:38, Hao Zhang <quic_hazha@quicinc.com> wrote:
>>
>> Hi Krzysztof,
>>
>> On 3/25/2023 7:49 PM, Krzysztof Kozlowski wrote:
>>> On 24/03/2023 07:16, Hao Zhang wrote:
>>>> Add new coresight-dummy.yaml file describing the bindings required
>>>> to define coresight dummy trace in the device trees.
>>>>
>>>
>>> Subject: drop second/last, redundant "YAML schema". The "dt-bindings"
>>> prefix is already stating that these are bindings and all new must be DT
>>> schema. You cannot add anything else, so this is redundant.
>>>
>> I will take your advice to drop redundant part of title in the next
>> version of patch.
>>>
>>>> Signed-off-by: Hao Zhang <quic_hazha@quicinc.com>
>>>> ---
>>>>    .../bindings/arm/qcom,coresight-dummy.yaml    | 118 ++++++++++++++++++
>>>>    1 file changed, 118 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml b/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml
>>>> new file mode 100644
>>>> index 000000000000..7b719b084d72
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/arm/qcom,coresight-dummy.yaml
>>>> @@ -0,0 +1,118 @@
>>>> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
>>>> +# Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/arm/qcom,coresight-dummy.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: QCOM Coresight Dummy component
>>>> +
>>>> +description: |
>>>> +  The Coresight Dummy component is for the specific devices that HLOS don't have
>>>> +  permission to access or configure. Such as Coresight sink EUD, some TPDMs etc.
>>>> +  So there need driver to register dummy devices as Coresight devices. Provide
>>>> +  Coresight API for dummy device operations, such as enabling and disabling
>>>> +  dummy devices. Build the Coresight path for dummy sink or dummy source for
>>>> +  debugging.
>>>> +
>>>> +  The primary use case of the coresight dummy is to build path for dummy sink or
>>>> +  dummy source.
>>>> +
>>>> +maintainers:
>>>> +  - Mao Jinlong <quic_jinlmao@quicinc.com>
>>>> +  - Tao Zhang <quic_taozha@quicinc.com>
>>>> +  - Hao Zhang <quic_hazha@quicinc.com>
>>>> +
>>>> +select:
>>>> +  properties:
>>>> +    compatible:
>>>> +      contains:
>>>> +        enum:
>>>> +          - qcom,coresight-dummy
> 
> Can we have coresight-dummy-source and coresight-dummy-sink?

Sure, I will take your advice in the next version of patch.

> 
>>>> +  required:
>>>> +    - compatible
>>>
>>> Why do you need the select?
>>>
>> This is a mistake, will remove it in the next version of patch.
>>>> +
>>>> +properties:
>>>> +  $nodename:
>>>> +    pattern: "^dummy_.*(sink|source)_[0-9]+.*$"
>>>
>>> We do not enforce node names in individual bindings. Why do you need it?
>>> Plus underscore is not even proper character...
>>>
>> I will remove this node.
>>
>>>> +  compatible:
>>>> +    items:
>>>
>>> Drop items. You have only one item, so no need for list.
>>
>> I will take your advice and update it in the next version of patch.
>>
>>>> +      - const: qcom,coresight-dummy
>>>> +
>>>> +  qcom,dummy-sink:
>>>> +    type: boolean
>>>> +    description:
>>>> +      Indicates that the type of this coresight node is dummy sink.
>>>
>>> You just duplicated property name. Write something useful.
>>>
>>>> +
>>>> +  qcom,dummy-source:
>>>> +    type: boolean
>>>> +    description:
>>>> +      Indicates that the type of this coresight node is dummy source.
>>>
>>> You just duplicated property name. Write something useful.
>>>
>>
> 
> These properties not required if the compatible name is more specific
> 

I will update it in the next version of patch.

>> Sure, I will add more details for it.
>>
>>>> +
>>>> +  out-ports:
>>>> +    description: |
>>>
>>> No need for |
>>>
>>>> +      Output connections from the dummy source to Coresight Trace bus.
>>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>>> +
>>>> +    properties:
>>>> +      port:
>>>> +        description: Output connection from the dummy source to Coresight
>>>> +            Trace bus.
>>>> +        $ref: /schemas/graph.yaml#/properties/port
>>>> +
>>>> +  in-ports:
>>>> +    description: |
>>>
>>> Ditto
>>>
>> I will remove it in the next version of patch.
>>
>>>> +      Input connections from the CoreSight Trace bus to dummy sink.
>>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>>> +
>>>> +    properties:
>>>> +      port:
>>>> +        description: Input connection from the Coresight Trace bus to
>>>> +            dummy sink.
>>>> +        $ref: /schemas/graph.yaml#/properties/port
>>>> +
>>>> +required:
>>>> +  - compatible
>>>> +
> 
> The binding should constrain out ports to dummy-source only, and in
> ports to dummy sink only.
> 
> Regards
> 
> Mike
> 

I will update it according to your advice in the next version of patch.

Thanks,
Hao

>>>> +additionalProperties: false
>>>> +
>>>> +oneOf:
>>>> +  - required:
>>>> +      - qcom,dummy-sink
>>>> +  - required:
>>>> +      - qcom,dummy-source
>>>> +
>>>> +examples:
>>>> +  # minimum dummy sink definition. dummy sink connect to coresight replicator.
>>>> +  - |
>>>> +    dummy_sink_1 {
>>>
>>> Node names should be generic, so "sink"
>>> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
>>>
>>>> +      compatible = "qcom,coresight-dummy";
>>>> +      qcom,dummy-sink;
>>>> +
>>>> +      in-ports {
>>>> +        port {
>>>> +          eud_in_replicator_swao: endpoint {
>>>> +            remote-endpoint =
>>>> +              <&replicator_swao_out_eud>;
>>>
>>> Why line break after =?
>>>
>>
>>>> +          };
>>>> +        };
>>>> +      };
>>>> +    };
>>>> +
>>>> +  # minimum dummy source definition. dummy source connect to coresight funnel.
>>>
>>> If you use sentences, then start with capital letter.
>>>
>>
>> I will update it according to your advice in the next version of patch.
>>
>>>> +  - |
>>>> +    dummy_source_1 {
>>>> +      compatible = "qcom,coresight-dummy";
>>>> +      qcom,dummy-source;
>>>> +
>>>> +      out-ports {
>>>> +        port {
>>>> +          dummy_riscv_out_funnel_swao: endpoint {
>>>> +            remote-endpoint =
>>>> +              <&funnel_swao_in_dummy_riscv>;
>>>
>>> Why line break?
>>
>> I copy it from device tree and keep the original format, will correct
>> the format in the next version of patch.
>>
>> Thanks,
>> Hao
>>
>>>> +          };
>>>> +        };
>>>> +      };
>>>> +    };
>>>> +
>>>> +...
>>>
>>> Best regards,
>>> Krzysztof
>>>
> 
> 
>