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Message-ID: <DU0PR04MB941782E74ED59EB3AA93860788349@DU0PR04MB9417.eurprd04.prod.outlook.com>
Date: Tue, 15 Feb 2022 08:42:04 +0000
From: Peng Fan <peng.fan@....com>
To: Arnaud POULIQUEN <arnaud.pouliquen@...s.st.com>,
"Peng Fan (OSS)" <peng.fan@....nxp.com>,
"bjorn.andersson@...aro.org" <bjorn.andersson@...aro.org>,
"mathieu.poirier@...aro.org" <mathieu.poirier@...aro.org>,
"linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH V2] remoteproc: support self recovery after rproc crash
> Subject: Re: [PATCH V2] remoteproc: support self recovery after rproc crash
>
> Hi Peng,
>
> On 1/26/22 09:51, Peng Fan (OSS) wrote:
> > From: Peng Fan <peng.fan@....com>
> >
> > Current logic only support main processor to stop/start the remote
> > processor after rproc crash. However to SoC, such as i.MX8QM/QXP, the
> > remote processor could do self recovery after crash and trigger
> > watchdog reboot. It does not need main processor to load image,
> > stop/start M4 core.
>
>
> On stm32mp1 platform the remote processor watchdog generates an early
> interrupt that could be used to detach and reattach before the reset of the
> remote processor.
> I need to test race condition,but I suppose that this should works if the
> resource table is not reinitialized by the remote processor firmware.
In i.MX8QM/QXP partition setup, resource table will be reinitialized by
remote firmware.
>
> Another option for the stm32mp1 is that remoteproc manages the reset of
> the remote processor.
> For instance this allows to save a core-dump before manually resetting the
> remote processor.
> But looks like this use case can be handled later, as mentioned below.
>
> >
> > This patch add a new flag to indicate whether the SoC has self
> > recovery capability. And introduce two functions: rproc_self_recovery,
> > rproc_assisted_recovery for the two cases. Assisted recovery is as
> > before, let main processor to help recovery, while self recovery is
> > recover itself withou help. To self recovery, we only do detach and
> > attach.
>
>
> >
> > Signed-off-by: Peng Fan <peng.fan@....com>
> > ---
> >
> > V2:
> > Nothing change in V2.
> > Only move this patch out from
> >
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatc
> >
> hwork.kernel.org%2Fproject%2Flinux-remoteproc%2Flist%2F%3Fseries%3D6
> 04
> >
> 364&data=04%7C01%7Cpeng.fan%40nxp.com%7C9e8a4ea774124a896f
> ed08d9ef
> >
> e9ac6c%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637804609
> 168765154
> > %7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzI
> iLCJBTiI6I
> >
> k1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=ewUl7diAOfkomSQMiPDQ
> o5A6c2Hklgo
> > 8xYbMBk5A4Ic%3D&reserved=0
> >
> > drivers/remoteproc/remoteproc_core.c | 66
> ++++++++++++++++++++--------
> > include/linux/remoteproc.h | 2 +
> > 2 files changed, 49 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c
> > b/drivers/remoteproc/remoteproc_core.c
> > index 69f51acf235e..4bd5544dab8f 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -1887,6 +1887,49 @@ static int __rproc_detach(struct rproc *rproc)
> > return 0;
> > }
> >
> > +static int rproc_self_recovery(struct rproc *rproc) {
> > + int ret;
> > +
> > + mutex_unlock(&rproc->lock);
> > + ret = rproc_detach(rproc);
> > + mutex_lock(&rproc->lock);
> > + if (ret)
> > + return ret;
>
> Here we would want to perform a core dump and manually reset the
> co-processor.
It is self recovery, not needed manual reset from main processor.
> I suppose that a new rproc ops could be called here in a next step.
Not very sure, but core dump could be added if needed.
>
> > +
> > + if (atomic_inc_return(&rproc->power) > 1)
> > + return 0;
>
> Do you identify a use case that needs to test rproc->power to skip the attach?
> If yes could you add a comment to describe it?
Just to avoid some error path. I think only when power is 1,
and self recovery could attach again.
>
> > + return rproc_attach(rproc);
> > +}
> > +
> > +static int rproc_assisted_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
> > @@ -1901,7 +1944,6 @@ 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;
> >
> > @@ -1915,24 +1957,10 @@ 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->self_recovery)
> > + ret = rproc_self_recovery(rproc);
>
> If some platforms have to manually reset the remote processor (without
> reloading the firmware) the name could not be relevant...
>
> Following comments are only suggestions that needs to be commented by
> maintainers
>
> What about rproc_attach_recovery ?
Looks better.
>
> > + else
> > + ret = rproc_assisted_recovery(rproc);
>
> and rproc_firmware_recovery ?
Yeah, better.
>
>
> >
> > unlock_mutex:
> > mutex_unlock(&rproc->lock);
> > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > index e0600e1e5c17..b32ef46f8aa4 100644
> > --- a/include/linux/remoteproc.h
> > +++ b/include/linux/remoteproc.h
> > @@ -529,6 +529,7 @@ struct rproc_dump_segment {
> > * @elf_machine: firmware ELF machine
> > * @cdev: character device of the rproc
> > * @cdev_put_on_release: flag to indicate if remoteproc should be
> > shutdown on @char_dev release
> > + * @self_recovery: flag to indicate if remoteproc support self
> > + recovery
> > */
> > struct rproc {
> > struct list_head node;
> > @@ -568,6 +569,7 @@ struct rproc {
> > u16 elf_machine;
> > struct cdev cdev;
> > bool cdev_put_on_release;
> > + bool self_recovery;
>
> This bool seems needed because we have lost the previous state before crash.
> I wonder if a new rproc->state such as RPROC_REBOOT could avoid this
> boolean.
REBOOT not able to differentiable self recovery or firmware recovery?
Anyway I'll check to add a BIT instead a bool.
>
>
> I will try to test you patch on stm32mp1 next week
Thanks,
Peng.
>
> Regards,
> Arnaud
>
> > };
> >
> > /**
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