linux-kernel - Re: [PATCH] remoteproc: qcom: Add NOTIFY

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Message-ID: <468b5a6d-53b7-4d75-8966-2fd48bb13d54@quicinc.com>
Date: Wed, 7 Feb 2024 21:51:18 +0530
From: Vignesh Viswanathan <quic_viswanat@...cinc.com>
To: Bjorn Andersson <andersson@...nel.org>
CC: <agross@...nel.org>, <konrad.dybcio@...aro.org>,
        <mathieu.poirier@...aro.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-remoteproc@...r.kernel.org>,
        <quic_srichara@...cinc.com>, <quic_varada@...cinc.com>,
        <quic_kathirav@...cinc.com>, <quic_devipriy@...cinc.com>,
        <quic_sjaganat@...cinc.com>
Subject: Re: [PATCH] remoteproc: qcom: Add NOTIFY_FATAL event type to SSR
 subdevice



On 11/25/2023 12:24 AM, Vignesh Viswanathan wrote:
> 
> 
> On 9/4/2023 10:23 PM, Vignesh Viswanathan wrote:
>>
>>
>> On 7/16/2023 1:50 AM, Bjorn Andersson wrote:
>>> On Wed, May 03, 2023 at 11:51:46AM +0530, Vignesh Viswanathan wrote:
>>>> Currently the SSR subdevice notifies the client driver on crash of the
>>>> rproc from the recovery workqueue using the BEFORE_SHUTDOWN event.
>>>> However the client driver might be interested to know that the device
>>>> has crashed immediately to pause any further transactions with the
>>>> rproc. This calls for an event to be sent to the driver in the IRQ
>>>> context as soon as the rproc crashes.
>>>>
>>>
>>> Please make your argumentation more concrete, I can only guess what
>>> client driver you're referring to.
>>>
>>> You can do this either by spelling out which actual problem you're
>>> solving, or better yet, include some patches in the series that actually
>>> uses this interface.
>>>
>>
>> Hi Bjorn,
>>
>> Apologies for the delay in response.
>>
>> The client driver in my scenario is a Wi-Fi driver which is continuously
>> queuing data to the remoteproc and needs to know if remoteproc crashes
>> as soon as possible to stop queuing further data and also dump some debugstatistics on the driver side that could potentially help in debug
>> of why the remoteproc crashed.
>>
>> Also in the case with upcoming Wi-Fi 7 targets with multi-link operation, the driver might need to know that the remoteproc has crashed
>> instantly to handle some multi-link specific handling.
>>
>> The ath11k/ath12k WLAN drivers today partially have support for handling
>> such FATAL notification but it has not been upstreamed yet.
>>
>> Reference patch: https://git.codelinaro.org/clo/qsdk/oss/system/feeds/wlan-open/-/blob/win.wlan_host_opensource.1.0/mac80211/patches/031-ath11k-print-stats-on-crash.patch -- event SUBSYS_PREPARE_FOR_FATAL_SHUTDOWN.
>>
>> Also, Mukesh mentioned earlier that in some MSM targets with PCIe where latency cannot be tolerated, a similar downstream patch adds support for "early notifier". If this patch is accepted, the early notifier can also be replaced to use the same NOTIFY_FATAL event from SSR Subdevice
>>
>> https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/commit/7583d24de337aa1bf7c375a7da706af9b995b9a1#a840754ebb0e24e88adbf48177e1abd0830b72d2
>> https://git.codelinaro.org/clo/la/kernel/msm-5.15/-/commit/257de41c63a5a51a081cc7887cdaa4a46e4d1744
> 
> Hi Bjorn,
> 
> Gentle reminder for this patch.
> 
> Thanks,
> Vignesh

Hi Bjorn,

Could you please help review this patch and let me know if any comments.

Thanks,
Vignesh
>>
>> Thanks,
>> Vignesh
>>
>>> Regards,
>>> Bjorn