linux-kernel - Re: [PATCH v2 01/22] dt-bindings: net: wireless: describe the ath12k AHB module

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Message-ID: <2d10224e-102c-4508-99f4-5743588d0686@quicinc.com>
Date: Wed, 27 Nov 2024 12:54:31 +0530
From: Raj Kumar Bhagat <quic_rajkbhag@...cinc.com>
To: Krzysztof Kozlowski <krzk@...nel.org>
CC: <ath12k@...ts.infradead.org>, <linux-wireless@...r.kernel.org>,
        Kalle Valo
	<kvalo@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski
	<krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jeff Johnson
	<jjohnson@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio
	<konradybcio@...nel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v2 01/22] dt-bindings: net: wireless: describe the ath12k
 AHB module

On 10/16/2024 2:30 PM, Krzysztof Kozlowski wrote:
>>>> +    description:
>>>> +      phandle to a node describing reserved memory (System RAM memory)
>>>> +      used by ath12k firmware (see bindings/reserved-memory/reserved-memory.txt)
>>>> +
>>>> +  qcom,rproc:
>>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>>> +    description:
>>>> +      DT entry of a WCSS node. WCSS node is the child node of q6 remoteproc driver.
>>>> +      (see bindings/remoteproc/qcom,multipd-pil.yaml)
>>> DT nodes are not children of drivers. But other DT nodes. Explain why
>>> this phandle is needed, what is it for.
>>>
>>> To me it looks like you incorrectly organized your nodes.
>>>
>> This phandle is required by wifi driver (ath12k) to retrieve the correct remote processor
>> (rproc_get_by_phandle()). Ath12k driver needs this rproc to interact with the remote
>> processor (example: booting-up remote processor).
> That's driver aspect. Why does the hardware needs it?
> 
> WiFi is the remote processor, so I would expect this being a child. Or
> just drop entirely.
> 
> You keep using here arguments how you designed your drivers, which is
> not valid. Sorry, fix your drivers... or use arguments in terms of hardware.
> 
> 
>> In next version, will correct the description based on existing bindings (qcom,ath11k.yaml).
> Sorry, let's don't copy existing solutions just because they exist.

In the IPQ5332 platform, the WiFi component, known as the Wireless Control Subsystem (WCSS),
functions as the wireless controller. Additionally, there is a separate hardware module, the
Qualcomm Hexagon DSP(q6 remote processor), which is utilized for offloading WiFi processing
tasks. These two hardware modules operate in conjunction, necessitating a phandle in the WiFi
node that references the remote processor. Despite their interdependence, these modules are
distinct from a hardware perspective.