linux-kernel - Re: [PATCH V2 01/13] dt-bindings: remoteproc: qcom: Add support for multipd model

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Message-ID: <0fbbb9c9-f215-cf41-ec34-8c726a167bbf@quicinc.com>
Date:   Tue, 18 Jul 2023 17:40:59 +0530
From:   Manikanta Mylavarapu <quic_mmanikan@...cinc.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Kalle Valo <kvalo@...nel.org>
CC:     <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <jassisinghbrar@...il.com>, <mathieu.poirier@...aro.org>,
        <mturquette@...libre.com>, <sboyd@...nel.org>,
        <quic_eberman@...cinc.com>, <quic_mojha@...cinc.com>,
        <loic.poulain@...aro.org>, <linux-arm-msm@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <quic_srichara@...cinc.com>, <quic_sjaganat@...cinc.com>,
        <quic_kathirav@...cinc.com>, <quic_anusha@...cinc.com>,
        <quic_poovendh@...cinc.com>, <quic_varada@...cinc.com>,
        <quic_devipriy@...cinc.com>
Subject: Re: [PATCH V2 01/13] dt-bindings: remoteproc: qcom: Add support for
 multipd model



On 7/1/2023 4:21 PM, Krzysztof Kozlowski wrote:
> On 30/06/2023 09:12, Manikanta Mylavarapu wrote:
>>
>>
>> On 6/24/2023 12:49 PM, Krzysztof Kozlowski wrote:
>>> On 21/06/2023 13:39, Manikanta Mylavarapu wrote:
>>>>>> on number of wcss radios connected on that board and only one instance
>>>>>> of 'qcom,ipq5018-q6-mpd'.
>>>>>>
>>>>>
>>>>> I don't understand why the user protection domains need a specific
>>>>> compatible. Why do they need compatible at all?
>>>>>
>>>>> Not mentioning that amount of your domains on Q6 is actually fixed per
>>>>> SoC and probably should not be in DT at all.
>>>>>
>>>>      root domain is fixed per soc (One Q6 DSP, one per soc)
>>>>      user domain(s) are variable (based on number of wcss radios attached)
>>>>
>>>>      The sequence to initialize, bring up, tear down the Q6 and wcss radios
>>>>      are completely different. So in order to differentiate them, we will
>>>>      need different compatibles. So this is a new rproc driver/architecture
>>>>      which has a parent/child topology (Q6 DSP -> Master/parent controls
>>>>      the WCSS (child)).
>>>
>>> I understand you need different properties, but I don't see yet the
>>> benefit of creating here artificial compatibles. Look at your ipq9574
>>> DTSI change - it does not use even ipq9574 compatibles for 66% of its
>>> children.
>>>
>>> Maybe you should have there just property describing type of device or
>>> bringup?
>>>
>>
>> 	Yeah i got your point. Indeed the requirement here is to
>> 	have device specific compatibles, so will have just two
>> 	compatible one for Q6-MPD and another for WCSS-MPD device's
>>
>>
>> 	"qcom,q6-mpd" --> For Q6-MPD device
>> 	"qcom,wcss-mpd" --> For WCSS-MPD device
>>
>> 	Is this approach fine ?
> 
> Can you fix your reply style, so it is like on every mailing list? Some
> weird indentation does no help to read it.
>

Sure, i will change my reply style and don't use any indentation.
Sorry for inconvenience.

> I was proposing to drop compatibles entirely. Making compatibles generic
> is not solving any of my concerns.
> 
> I don't understand what do you want to achieve here and very limited
> description of the hardware in the binding does not help.
> 

Sure, i remove user pd compatibles. In root pd probe itself, user pd
remoteproc's are taken care. Also I updated diagram in cover page, it
gives enough information.

>>
>>> Given SoC cannot come with different amount of children (PD) and
>>> different amount of radios. You even fix the firmware name, so
>>> boards/customers cannot use anything else. It's fixed and the only
>>> variable element here is disabling some of the blocks per board, if they
>>> do not have physical interface (e.g. radio).
>>>
>>> You even hard-code the number of PD by using "pd-[123]", without unit
>>> address, so you do not expect it will grow.
>>>
>>> Unless you want to say that these are devices? But your binding does not
>>> really suggest it...
>>>
>>>
>>> 	Yes, as i mentioned above the requirement is to have device
> 
> What requirement? You did not describe anything. Binding describes
> hardware, not your requirements.
> 
> Binding said nothing about devices.
> 

Yeah got your point. So we removed userpd compatibles from dt-bindings.


>> 	specific bindings. We will remove "PD-X" from soc dtsi and
>> 	add it in board dts file.
> 
> Why? How is it related to the bindings? What does it solve? Instead of
> doing some changes you should explain why.
> 
>>
>> 	So soc dts would have "Q6-MPD" master node & board dts have
>> 	"WCSS-MPD" child nodes based on number of radio's connected
>> 	on board.
>>
>> 	Is this fine ?
>>
> 
> Why?
> 

"PD-X" controls user pd WCSS bring up. WCSS blocks may vary based on
number of radio's connected on board but QDSP6 is always present.
So i will keep Q6 node in soc dtsi file and move 'PD-X' node to board
dts file.

Thanks & Regards,
Manikanta.

> Best regards,
> Krzysztof
>