Re: [PATCH V7 2/2] remoteproc: support attach recovery after rproc crash

[Peng Fan <peng.fan@oss.nxp.com>]

On 9/28/2022 1:44 AM, Mathieu Poirier wrote:
> On Tue, Sep 27, 2022 at 10:10:31AM +0200, Arnaud POULIQUEN wrote:
>> Hi,
>>
>> On 9/27/22 05:03, Peng Fan wrote:
>>> Hi Mathieu,
>>>
>>>> Subject: Re: [PATCH V7 2/2] remoteproc: support attach recovery after rproc
>>>> crash
>>>>
>>>> On Tue, Jul 05, 2022 at 09:15:27AM +0800, Peng Fan (OSS) wrote:
>>>>> From: Peng Fan <peng.fan@nxp.com>
>>>>>
>>>>> Current logic only support main processor to stop/start the remote
>>>>> processor after crash. However to SoC, such as i.MX8QM/QXP, the remote
>>>>> processor could do attach recovery after crash and trigger watchdog to
>>>>> reboot itself. It does not need main processor to load image, or
>>>>> stop/start remote processor.
>>>>>
>>>>> Introduce two functions: rproc_attach_recovery, rproc_boot_recovery
>>>>> for the two cases. Boot recovery is as before, let main processor to
>>>>> help recovery, while attach recovery is to recover itself without help.
>>>>> To attach recovery, we only do detach and attach.
>>>>>
>>>>> Acked-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>>>> Signed-off-by: Peng Fan <peng.fan@nxp.com>
>>>>> ---
>>>>>   drivers/remoteproc/remoteproc_core.c | 62
>>>>> +++++++++++++++++++---------
>>>>>   1 file changed, 43 insertions(+), 19 deletions(-)
>>>>>
>>>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>>>> b/drivers/remoteproc/remoteproc_core.c
>>>>> index ed374c8bf14a..ef5b9310bc83 100644
>>>>> --- a/drivers/remoteproc/remoteproc_core.c
>>>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>>>> @@ -1884,6 +1884,45 @@ static int __rproc_detach(struct rproc *rproc)
>>>>>   	return 0;
>>>>>   }
>>>>>
>>>>> +static int rproc_attach_recovery(struct rproc *rproc) {
>>>>> +	int ret;
>>>>> +
>>>>> +	ret = __rproc_detach(rproc);
>>>>> +	if (ret)
>>>>> +		return ret;
>>>>
>>>> I thought there was a specific reason to _not_ call rproc->ops->coredump()
>>>> for processors that have been attached to but looking at the STM32 and
>>>> IMX_DSP now, it would seem logical to do so.  Am I missing something?
>>>
>>> ATTACH RECOVERY is to support recovery without help from Linux,
>>>
>>> STM32 and IMX_DSP, both require linux to load image and start remote
>>> core. So the two cases should not enable feature:
>>> RPROC_FEAT_ATTACH_ON_RECOVERY
>>>
>>> Also considering the recovery is out of linux control, actually when linux
>>> start dump, remote core may already recovered.
>>
>> I asked myself the same question. Indeed how to manage a core dump if the
>> remote processor restarts autonomously.
>> The answer doesn't seem obvious because it seems to be platform specific.
>>
>> For time being on STM32 we consider that the remoteproc memory can be corrupted
>> so we don't plan to enable the feature by default even if the hardware allows it.
>>
>> If we implement it, I would see 2 use cases:
>> - no core dump, the remote processor restart autonomously (need to manage the
>> VIRTIO_CONFIG_S_NEEDS_RESET in resource table vdev for resynchronization)
>> - core dump and the Linux stm32 driver handle the reset of the remote
>> processor core to be able to perform the core dump (no firmware loading)
>>
>> What about dealing with the coredump in a separate thread, based on a concrete
>> use case/need?
> 
> Definitely, we can deal with that later.
> 
> Peng - please send me a rebase as quickly as possible.

Mathieu,

Just send out V8 rebased on linux-next/master tag: next-20220927

Thanks,
Peng.
> 
>>
>> Regards,
>> Arnaud
>>   
>>>
>>>>
>>>> And this set will need a rebase.
>>>
>>> I'll do the rebase and send V8 if the upper explanation could eliminate
>>> your concern.
>>>
>>> Thanks,
>>> Peng.
>>>
>>>>
>>>> Thanks,
>>>> Mathieu
>>>>
>>>>> +
>>>>> +	return __rproc_attach(rproc);
>>>>> +}
>>>>> +
>>>>> +static int rproc_boot_recovery(struct rproc *rproc) {
>>>>> +	const struct firmware *firmware_p;
>>>>> +	struct device *dev = &rproc->dev;
>>>>> +	int ret;
>>>>> +
>>>>> +	ret = rproc_stop(rproc, true);
>>>>> +	if (ret)
>>>>> +		return ret;
>>>>> +
>>>>> +	/* generate coredump */
>>>>> +	rproc->ops->coredump(rproc);
>>>>> +
>>>>> +	/* load firmware */
>>>>> +	ret = request_firmware(&firmware_p, rproc->firmware, dev);
>>>>> +	if (ret < 0) {
>>>>> +		dev_err(dev, "request_firmware failed: %d\n", ret);
>>>>> +		return ret;
>>>>> +	}
>>>>> +
>>>>> +	/* boot the remote processor up again */
>>>>> +	ret = rproc_start(rproc, firmware_p);
>>>>> +
>>>>> +	release_firmware(firmware_p);
>>>>> +
>>>>> +	return ret;
>>>>> +}
>>>>> +
>>>>>   /**
>>>>>    * rproc_trigger_recovery() - recover a remoteproc
>>>>>    * @rproc: the remote processor
>>>>> @@ -1898,7 +1937,6 @@ static int __rproc_detach(struct rproc *rproc)
>>>>>    */
>>>>>   int rproc_trigger_recovery(struct rproc *rproc)  {
>>>>> -	const struct firmware *firmware_p;
>>>>>   	struct device *dev = &rproc->dev;
>>>>>   	int ret;
>>>>>
>>>>> @@ -1912,24 +1950,10 @@ int rproc_trigger_recovery(struct rproc
>>>>> *rproc)
>>>>>
>>>>>   	dev_err(dev, "recovering %s\n", rproc->name);
>>>>>
>>>>> -	ret = rproc_stop(rproc, true);
>>>>> -	if (ret)
>>>>> -		goto unlock_mutex;
>>>>> -
>>>>> -	/* generate coredump */
>>>>> -	rproc->ops->coredump(rproc);
>>>>> -
>>>>> -	/* load firmware */
>>>>> -	ret = request_firmware(&firmware_p, rproc->firmware, dev);
>>>>> -	if (ret < 0) {
>>>>> -		dev_err(dev, "request_firmware failed: %d\n", ret);
>>>>> -		goto unlock_mutex;
>>>>> -	}
>>>>> -
>>>>> -	/* boot the remote processor up again */
>>>>> -	ret = rproc_start(rproc, firmware_p);
>>>>> -
>>>>> -	release_firmware(firmware_p);
>>>>> +	if (rproc_has_feature(rproc, RPROC_FEAT_ATTACH_ON_RECOVERY))
>>>>> +		ret = rproc_attach_recovery(rproc);
>>>>> +	else
>>>>> +		ret = rproc_boot_recovery(rproc);
>>>>>
>>>>>   unlock_mutex:
>>>>>   	mutex_unlock(&rproc->lock);
>>>>> --
>>>>> 2.25.1
>>>>>