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Message-ID: <443edf61-2a28-4ae7-ac88-2da2d29cebe3@quicinc.com>
Date: Fri, 22 Mar 2024 15:02:22 +0800
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Subject: Re: [PATCH 1/4] dt-bindings: arm: qcom,coresight-funnel: Add label
 for multi-ouput
To: Rob Herring <robh@kernel.org>, Tao Zhang <quic_taozha@quicinc.com>
CC: 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>,
        Mike Leach <mike.leach@linaro.org>,
        Krzysztof Kozlowski
	<krzysztof.kozlowski+dt@linaro.org>,
        Jinlong Mao <quic_jinlmao@quicinc.com>, 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>,
        Yuanfang Zhang <quic_yuanfang@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Song Chai <quic_songchai@quicinc.com>, <linux-arm-msm@vger.kernel.org>,
        <andersson@kernel.org>
References: <1711009927-17873-1-git-send-email-quic_taozha@quicinc.com>
 <1711009927-17873-2-git-send-email-quic_taozha@quicinc.com>
 <20240321144226.GA1689544-robh@kernel.org>
From: Tingwei Zhang <quic_tingweiz@quicinc.com>
In-Reply-To: <20240321144226.GA1689544-robh@kernel.org>
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On 3/21/2024 10:42 PM, Rob Herring wrote:
> On Thu, Mar 21, 2024 at 04:32:04PM +0800, Tao Zhang wrote:
>> Add new property "label" to label the source corresponding to the
>> output connection. When the funnel supports multi-output, this
>> property needs to be introduced to mark which source component a
>> certain output connection corresponds to.
>>
>> Signed-off-by: Tao Zhang <quic_taozha@quicinc.com>
>> ---
>>   .../arm/arm,coresight-dynamic-funnel.yaml     | 34 ++++++++++++++++---
>>   1 file changed, 30 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/arm,coresight-dynamic-funnel.yaml b/Documentation/devicetree/bindings/arm/arm,coresight-dynamic-funnel.yaml
>> index 44a1041cb0fc..cde62c286d29 100644
>> --- a/Documentation/devicetree/bindings/arm/arm,coresight-dynamic-funnel.yaml
>> +++ b/Documentation/devicetree/bindings/arm/arm,coresight-dynamic-funnel.yaml
>> @@ -66,13 +66,39 @@ properties:
>>           $ref: /schemas/graph.yaml#/properties/port
>>   
>>     out-ports:
>> -    $ref: /schemas/graph.yaml#/properties/ports
>> -    additionalProperties: false
>> -
>> +    type: object
>>       properties:
>> +      "#address-cells":
>> +        const: 1
>> +
>> +      "#size-cells":
>> +        const: 0
>> +
>>         port:
>> +        type: object
>> +
>> +    patternProperties:
>> +      '^port(@[0-7])?$':
>> +        type: object
>>           description: Output connection to CoreSight Trace bus
>> -        $ref: /schemas/graph.yaml#/properties/port
> 
> Nope, now you have no constraints on port node properties. Please look
> at how other bindings are done to add properties on endpoint node.
> 
Thanks for pointing this out, Rob. Shall we ref port-base and
endpoint-base then add new properties on endpoint? In this way, the 
redundant code from port schema is not required.
>> +
>> +        patternProperties:
>> +          "^endpoint(@[0-9a-f]+)?$":
>> +            type: object
>> +            properties:
>> +              remote-endpoint:
>> +                description: |
>> +                  phandle to an 'endpoint' subnode of a remote device node.
>> +                  $ref: /schemas/types.yaml#/definitions/phandle
> 
> Don't need this.
> 
>> +              label:
>> +                description: Label the source corresponding to the output connection
>> +                $ref: /schemas/types.yaml#/definitions/string
> 
> label already has a type.
> 
> As this node is an output, aren't you labeling what the destination is,
> not the "source"?
> 
> Why can't you look at the remote connection to identify what it is?
>
This funnel can route data stream from different trace source to 
different output ports. This lable property is added to describe which 
source is routed to this output port.

For example, the graph is as below. Funnel3 routes trace data from TPDM0 
to output[0] and output[0] of funnel3 is connected to input[0] of TPDA0.
While Funnels routes trace data from TPDM1 to output[1] which connects 
to input[1] of TPDA0. Hope that clarifies this a little bit.

|---------|    |---------|    |---------|    |---------|    |---------|
|  TPDM0  |    |  TPDM1  |    |  TPDM2  |    |  TPDM3  |    |  TPDM4  |
|---------|    |---------|    |---------|    |---------|    |---------|
     |               |             |               |              |
     |               |             |               |              |
     |               |             |               |              |
     |-----|   |-----|             |-----|   |-----|              |
           |   |                         |   |                    |
           |   |                         |   |                    |
        [0]|   |[1]                   [0]|   |[1]                 |
      \-------------/               \-------------/        \------------/
       \  FUNNEL0  /                 \  FUNNEL1  /          \  FUNNEL2  /
        -----------                   -----------            -----------
             |                             |                      |
      \-------------/               \-------------/               |
       \  FUNNEL3  /                 \  FUNNEL4  /                |
        -----------                   -----------                 |
           |  |                         |   |
        [0]|  |[1]                   [0]|   |[1]                  |
           |  |----------               |   |                     |
           |            |               |   |                     |
           |-------|    |      |------- |   |          |--------- |
                   |    |      |            |          |
                   |    |      |            |          |
                [0]|    |[1]   |[2]         |[3]       |[4]
            \ ---------------------------------------------------/
             \                     TPDA0                        /
              \                                                /
               ------------------------------------------------

> 
>> +    oneOf:
>> +      - required:
>> +          - port
>> +      - required:
>> +          - "#address-cells"
>> +          - "#size-cells"
> 
> The common schema that you removed handles this.
> 
> Rob

-- 
Thanks,
Tingwei