linux-kernel - Re: [PATCH V6 1/3] dt-bindings: sram: qcom,imem: Add Boot Stat region within IMEM

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Message-ID: <10fa20f9-33d9-a8a8-3fca-f5ff320a6574@quicinc.com>
Date:   Tue, 9 May 2023 17:51:47 +0530
From:   Souradeep Chowdhury <quic_schowdhu@...cinc.com>
To:     Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, Sibi Sankar <quic_sibis@...cinc.com>,
        "Rajendra Nayak" <quic_rjendra@...cinc.com>
Subject: Re: [PATCH V6 1/3] dt-bindings: sram: qcom,imem: Add Boot Stat region
 within IMEM



On 5/9/2023 5:05 PM, Dmitry Baryshkov wrote:
> On Tue, 9 May 2023 at 13:53, Souradeep Chowdhury
> <quic_schowdhu@...cinc.com> wrote:
>>
>> All Qualcomm bootloaders log useful timestamp information related
>> to bootloader stats in the IMEM region. Add the child node within
>> IMEM for the boot stat region containing register address and
>> compatible string.
> 
> I might have a minor vote here. Is there any reason why you have to
> instantiate the device from DT?
> It looks like a software interface. Ideally software should not be
> described in DT (e.g. this can be instantiated from imem
> driver-to-be).
> Or we can follow the RPM master-stats approach, where the device is a
> top-level device, having handle pointers to the sram regions.

This is a dedicated region of IMEM reserved for storing stats related 
information. So it is represented as a child of IMEM, please
refer to Documentation/devicetree/bindings/sram/sram.yaml which
follows a similar philosophy. Also since this is a child of IMEM with
a specific purpose, does it not warrant a dedicated driver?

> 
>>
>> Signed-off-by: Souradeep Chowdhury <quic_schowdhu@...cinc.com>
>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> ---
>>   .../devicetree/bindings/sram/qcom,imem.yaml   | 22 +++++++++++++++++++
>>   1 file changed, 22 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/sram/qcom,imem.yaml b/Documentation/devicetree/bindings/sram/qcom,imem.yaml
>> index 0548e8e0d30b..bb884c5c8952 100644
>> --- a/Documentation/devicetree/bindings/sram/qcom,imem.yaml
>> +++ b/Documentation/devicetree/bindings/sram/qcom,imem.yaml
>> @@ -50,6 +50,28 @@ patternProperties:
>>       $ref: /schemas/remoteproc/qcom,pil-info.yaml#
>>       description: Peripheral image loader relocation region
>>
>> +  "^stats@[0-9a-f]+$":
>> +    type: object
>> +    description:
>> +      Imem region dedicated for storing timestamps related
>> +      information regarding bootstats.
>> +
>> +    additionalProperties: false
>> +
>> +    properties:
>> +      compatible:
>> +        items:
>> +          - enum:
>> +              - qcom,sm8450-bootstats
>> +          - const: qcom,imem-bootstats
>> +
>> +      reg:
>> +        maxItems: 1
>> +
>> +    required:
>> +      - compatible
>> +      - reg
>> +
>>   required:
>>     - compatible
>>     - reg
>> --
>> 2.17.1
>>
> 
>