linux-kernel - Re: [PATCH 1/2] soc: ti: Use remoteproc auto

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Message-ID: <1003ab4a-b481-4f60-097a-2ce607fa2961@codeaurora.org>
Date:   Tue, 3 Jan 2017 15:52:14 -0800
From:   Sarangdhar Joshi <spjoshi@...eaurora.org>
To:     Suman Anna <s-anna@...com>, Ohad Ben-Cohen <ohad@...ery.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Santosh Shilimkar <ssantosh@...nel.org>
Cc:     linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, Stephen Boyd <sboyd@...eaurora.org>,
        Trilok Soni <tsoni@...eaurora.org>,
        Dave Gerlach <d-gerlach@...com>
Subject: Re: [PATCH 1/2] soc: ti: Use remoteproc auto_boot feature

On 12/23/2016 03:57 PM, Suman Anna wrote:
> On 12/23/2016 11:05 AM, Suman Anna wrote:
>> Hi Sarang,
>>
>>>>
>>>> On 12/15/2016 06:03 PM, Sarangdhar Joshi wrote:
>>>>> The function wkup_m3_rproc_boot_thread waits for asynchronous
>>>>> firmware loading to complete successfully before calling
>>>>> rproc_boot(). The same can be achieved by just setting
>>>>> rproc->auto_boot flag. Change this. As a result this change
>>>>> removes wkup_m3_rproc_boot_thread and moves m3_ipc->sync_complete
>>>>> initialization to the wkup_m3_ipc_probe().
>>>>>
>>>>> Other than the current usage, the firmware_loading_complete is
>>>>> only used in rproc_del() where it's no longer needed.  This
>>>>> change is in preparation for removing firmware_loading_complete
>>>>> completely.
>>>>
>>>> Based on the comments so far, I am assuming that you are dropping this
>>>> series.
>>>
>>> No, may not be dropping this. Will try to handle it differently in
>>> rproc_del() (probably by making use of some state flag).
>>>>
>>>> In any case, this series did break our PM stack. We definitely don't
>>>> want to auto-boot the wkup_m3_rproc device, that responsibility will
>>>> need to stay with the wkup_m3_ipc driver.
>>>
>>> Which scenario did it break? Booting up rproc device before
>>> wkup_m3_ipc_probe() causes issues?
>>
>> Yes, our state machine requires the wkup_m3_ipc driver to control the
>> boot of the wkup_m3 remoteproc. The wkup_m3 is not a typical remoteproc,
>> it is our PM master and is responsible for putting the host processor
>> into suspend and waking it up in system suspend/cpuidle paths.
>> The remoteproc infrastructure is only used for load/boot, but the Linux
>> PM state machine and communication is all controlled by the wkup_m3_ipc
>> driver.

Thanks for explaining. I was missing the fact that the resource table 
parsing during asynchronous call and the one in rproc_boot() are 
different.

>>
>>>
>>> Nevertheless, I think Bjorn's suggestion of just dropping the call to
>>> wait_for_completion() and keeping kthread looks good, also because of
>>> the fact that rproc_boot() anyways calls request_firmware() and no
>>> longer needed to wait on asynchronous loading of firmware.
>>
>> Yeah, I will have to test this, but looking at current code, this should
>> mostly be ok because of the remoteproc core changes w.r.t resource table
>> parsing.
>
> Tested with just the wait_for_completion() removed and it works fine. I
> can send a patch for the same if you prefer me to send it.

Thanks for testing it. I have sent the patch.

Regards,
Sarang

>
> regards
> Suman
>
>>
>> regards
>> Suman
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