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

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Message-ID: <15042631-4012-61bd-11ef-dde378215fed@quicinc.com>
Date:   Thu, 11 May 2023 11:29:12 +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 6:35 PM, Dmitry Baryshkov wrote:
> On Tue, 9 May 2023 at 15:21, Souradeep Chowdhury
> <quic_schowdhu@...cinc.com> wrote:
>>
>>
>>
>> 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?
> 
> I do not question a dedicated driver. I was asking about the DT node.
> Even the mentioned bindings file describes the SRAM regions inside the
> SRAM, rather than a proper device to be instantiated in the SRAM node.
> I'd point to the boot_stats discussions (present on the list in the
> last several months).
> 

Ack. Will instantiate the device from the parent node in the driver and
access the stats region to print the boot_stats information.


>>
>>>
>>>>
>>>> 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
>>>>
>>>
>>>
> 
> 
>