linux-kernel - Re: [PATCH v12 04/36] remoteproc: k3-m4: Don't assert reset in detach routine

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Message-ID: <f480253a-225d-4941-af81-32e1a02bf793@ti.com>
Date: Tue, 20 May 2025 10:36:12 +0530
From: Beleswar Prasad Padhi <b-padhi@...com>
To: Mathieu Poirier <mathieu.poirier@...aro.org>
CC: <andersson@...nel.org>, <afd@...com>, <hnagalla@...com>, <u-kumar1@...com>,
        <jm@...com>, <jan.kiszka@...mens.com>, <christophe.jaillet@...adoo.fr>,
        <jkangas@...hat.com>, <eballetbo@...hat.com>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <martyn.welch@...labora.com>
Subject: Re: [PATCH v12 04/36] remoteproc: k3-m4: Don't assert reset in detach
 routine

Hi Mathieu,

On 19/05/25 20:07, Mathieu Poirier wrote:
> On Sat, May 17, 2025 at 06:53:29PM +0530, Beleswar Prasad Padhi wrote:
>> On 5/16/2025 9:15 PM, Mathieu Poirier wrote:
>>> On Tue, May 13, 2025 at 11:14:38AM +0530, Beleswar Padhi wrote:
>>>> The rproc_detach() function invokes __rproc_detach() before
>>>> rproc_unprepare_device(). The __rproc_detach() function sets the
>>>> rproc->state to "RPROC_DETACHED".
>>>>
>>>> However, the TI K3 M4 driver erroneously looks for "RPROC_ATTACHED"
>>>> state in its .unprepare ops to identify IPC-only mode; which leads to
>>>> resetting the rproc in detach routine.
>>>>
>>>> Therefore, correct the IPC-only mode detection logic to look for
>>>> "RPROC_DETACHED" in k3_m4_rproc_unprepare() function.
>>>>
>>> This driver has been upstream for 9 whole months, it is hard for me to believe
>>> this but was just noticed.  Martyn from Collabora should be CC'ed on this, and I
>>> will also need the required R-b/T-b tags.
>>
>> Cc: Martyn Welch martyn.welch@...labora.com
>>
>> Requesting Andrew/Judith for review and test too.
>>
>>> Typically bug fixes are not part of refactoring exercises.
>>
>> Typically, yes. But the refactor depends on this fix. This
>> k3_m4_rproc_unprepare() function is entirely refactored to common driver in
>> [PATCH v12 26/36].
>>
>> So, If the refactor is picked without this patch fix, the mainline M4 driver
>> would be fixed, but the older stable kernels would always have this bug. Let
>> me know what you think.
>>
> I suggest you send this patch on its own and then the series (without this
> patch) with a note in the cover letter that it depends on the fix.  That way we
> get the best of both worlds.


Sure. If I get any comments/reviews on this version, I will re-spin this patch separately than the series.

Thanks,
Beleswar

>
>> Thanks,
>> Beleswar
>>
>>>   I suggest to apply
>>> this set without this patch - you can then work on fixing this bug.
>>>
>>> Thanks,
>>> Mathieu
>>>
>>>> Fixes: ebcf9008a895 ("remoteproc: k3-m4: Add a remoteproc driver for M4F subsystem")
>>>> Signed-off-by: Beleswar Padhi <b-padhi@...com>
>>>> ---
>>>> v12: Changelog:
>>>> 1. New patch. Fixup a state detection logic.
>>>>
>>>>   drivers/remoteproc/ti_k3_m4_remoteproc.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/remoteproc/ti_k3_m4_remoteproc.c b/drivers/remoteproc/ti_k3_m4_remoteproc.c
>>>> index a16fb165fcedd..6cd50b16a8e82 100644
>>>> --- a/drivers/remoteproc/ti_k3_m4_remoteproc.c
>>>> +++ b/drivers/remoteproc/ti_k3_m4_remoteproc.c
>>>> @@ -228,7 +228,7 @@ static int k3_m4_rproc_unprepare(struct rproc *rproc)
>>>>   	int ret;
>>>>   	/* If the core is going to be detached do not assert the module reset */
>>>> -	if (rproc->state == RPROC_ATTACHED)
>>>> +	if (rproc->state == RPROC_DETACHED)
>>>>   		return 0;
>>>>   	ret = kproc->ti_sci->ops.dev_ops.put_device(kproc->ti_sci,
>>>> -- 
>>>> 2.34.1
>>>>