Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Wed, 20 May 2020 at 23:22, Bjorn Andersson
wrote:
>
> On Wed 20 May 15:06 PDT 2020, Mathieu Poirier wrote:
>
> > On Mon, May 18, 2020 at 05:55:00PM -0700, Bjorn Andersson wrote:
> > > On Fri 15 May 12:24 PDT 2020, Mathieu Poirier wrote:
> > >
> > > > Good day Bjorn,
> > > >
> > > > On Wed, May 13, 2020 at 06:32:24PM -0700, Bjorn Andersson wrote:
> > > > > On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
> > > > >
> > > > > > On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > > > > > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> [..]
> > > > > > > > + bool after_crash;
> > > > > > >
> > > > > > > Similarly what is the expected steps to be taken by the core when
> > > > > > > this
> > > > > > > is true? Should rproc_report_crash() simply stop/start the
> > > > > > > subdevices
> > > > > > > and upon one of the ops somehow tell the remote controller that
> > > > > > > it can
> > > > > > > proceed with the recovery?
> > > > > >
> > > > > > The exact same sequence of steps will be carried out as they are
> > > > > > today, except
> > > > > > that if after_crash == true, the remoteproc core won't be switching
> > > > > > the remote
> > > > > > processor on, exactly as it would do when on_init == true.
> > > > > >
> > > > >
> > > > > Just to make sure we're on the same page:
> > > > >
> > > > > after_crash = false is what we have today, and would mean:
> > > > >
> > > > > 1) stop subdevices
> > > > > 2) power off
> > > > > 3) unprepare subdevices
> > > > > 4) generate coredump
> > > > > 5) request firmware
> > > > > 6) load segments
> > > > > 7) find resource table
> > > > > 8) prepare subdevices
> > > > > 9) "boot"
> > > > > 10) start subdevices
> > > >
> > > > Exactly
> > > >
> > > > >
> > > > > after_crash = true would mean:
> > > > >
> > > > > 1) stop subdevices
> > > > > 2) "detach"
> > > > > 3) unprepare subdevices
> > > > > 4) prepare subdevices
> > > > > 5) "attach"
> > > > > 6) start subdevices
> > > > >
> > > >
> > > > Yes
> > > >
> > > > > State diagram wise both of these would represent the transition
> > > > > RUNNING
> > > > > -> CRASHED -> RUNNING, but somehow the platform driver needs to be
> > > > > able
> > > > > to specify which of these sequences to perform. Per your naming
> > > > > suggestion above, this does sound like a "autonomous_recovery" boolean
> > > > > to me.
> > > >
> > > > Right, semantically "rproc->autonomous" would apply quite well.
> > > >
> > > > In function rproc_crash_handler_work(), a call to rproc_set_sync_flag()
> > > > has been
> > > > strategically placed to set the value of rproc->autonomous based on
> > > > "after_crash". From there the core knows which rproc_ops to use. Here
> > > > too we
> > > > have to rely on the rproc_ops provided by the platform to do the right
> > > > thing
> > > > based on the scenario to enact.
> > > >
> > >
> > > Do you think that autonomous_recovery would be something that changes
> > > for a given remoteproc instance? I envisioned it as something that you
> > > know at registration time, but perhaps I'm missing some details here.
> >
> > I don't envision any of the transision flags to change once they are set by
> > the
> > platform. The same applies to the new rproc_ops, it can be set only once.
> > Otherwise combination of possible scenarios becomes too hard to manage,
> > leading
> > to situations where the core and MCU get out of sync and can't talk to each
> > other.
> >
>
> Sounds good, I share this expectation, just wanted to check with you.
>
> > >
> > > > >
> > > > > > These flags are there to indicate how to set rproc::sync_with_rproc
> > > > > > after
> > > > > > different events, that is when the remoteproc core boots, when the
> > > > > > remoteproc
> > > > > > has been stopped or when it has crashed.
> > > > > >
> > > > >
> > > > > Right, that was clear from your patches. Sorry that my reply didn't
> > > > > convey the information that I had understood this.
> > > > >
> > > > > > >
> > > > > > > > +};
> > > > > > > > +
> > > > > > > > /**
> > > > > > > > * struct rproc_ops - platform-specific device handlers
> > > > > > > > * @start: power on the device and boot it
> > > > > > > > @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> > > > > > > > * @firmware: name of firmware file to be loaded
> > > > > > > > * @priv: private data which belongs to the platform-specific
> > > > > > > > rproc module
> > > > > > > > * @ops: platform-specific start/stop rproc handlers
> > > > > > > > + * @sync_ops: platform-specific start/stop rproc handlers when
> > > > > > > > + * synchronising with a remote processor.
> > > > > > > > + * @sync_flags: Determine the rproc_ops to choose in specific
> > > > > > > > states.
> > > > > > > > * @dev: virtual device for refcounting and common remoteproc
> > > > > > > > behavior
> > > > > > > > * @power: refcount of users who need this rproc powered up
> > > > > > > > * @state: state of the device
> > > > > > >
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Wed 20 May 15:06 PDT 2020, Mathieu Poirier wrote:
> On Mon, May 18, 2020 at 05:55:00PM -0700, Bjorn Andersson wrote:
> > On Fri 15 May 12:24 PDT 2020, Mathieu Poirier wrote:
> >
> > > Good day Bjorn,
> > >
> > > On Wed, May 13, 2020 at 06:32:24PM -0700, Bjorn Andersson wrote:
> > > > On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
> > > >
> > > > > On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > > > > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
[..]
> > > > > > > + bool after_crash;
> > > > > >
> > > > > > Similarly what is the expected steps to be taken by the core when
> > > > > > this
> > > > > > is true? Should rproc_report_crash() simply stop/start the
> > > > > > subdevices
> > > > > > and upon one of the ops somehow tell the remote controller that it
> > > > > > can
> > > > > > proceed with the recovery?
> > > > >
> > > > > The exact same sequence of steps will be carried out as they are
> > > > > today, except
> > > > > that if after_crash == true, the remoteproc core won't be switching
> > > > > the remote
> > > > > processor on, exactly as it would do when on_init == true.
> > > > >
> > > >
> > > > Just to make sure we're on the same page:
> > > >
> > > > after_crash = false is what we have today, and would mean:
> > > >
> > > > 1) stop subdevices
> > > > 2) power off
> > > > 3) unprepare subdevices
> > > > 4) generate coredump
> > > > 5) request firmware
> > > > 6) load segments
> > > > 7) find resource table
> > > > 8) prepare subdevices
> > > > 9) "boot"
> > > > 10) start subdevices
> > >
> > > Exactly
> > >
> > > >
> > > > after_crash = true would mean:
> > > >
> > > > 1) stop subdevices
> > > > 2) "detach"
> > > > 3) unprepare subdevices
> > > > 4) prepare subdevices
> > > > 5) "attach"
> > > > 6) start subdevices
> > > >
> > >
> > > Yes
> > >
> > > > State diagram wise both of these would represent the transition RUNNING
> > > > -> CRASHED -> RUNNING, but somehow the platform driver needs to be able
> > > > to specify which of these sequences to perform. Per your naming
> > > > suggestion above, this does sound like a "autonomous_recovery" boolean
> > > > to me.
> > >
> > > Right, semantically "rproc->autonomous" would apply quite well.
> > >
> > > In function rproc_crash_handler_work(), a call to rproc_set_sync_flag()
> > > has been
> > > strategically placed to set the value of rproc->autonomous based on
> > > "after_crash". From there the core knows which rproc_ops to use. Here
> > > too we
> > > have to rely on the rproc_ops provided by the platform to do the right
> > > thing
> > > based on the scenario to enact.
> > >
> >
> > Do you think that autonomous_recovery would be something that changes
> > for a given remoteproc instance? I envisioned it as something that you
> > know at registration time, but perhaps I'm missing some details here.
>
> I don't envision any of the transision flags to change once they are set by
> the
> platform. The same applies to the new rproc_ops, it can be set only once.
> Otherwise combination of possible scenarios becomes too hard to manage,
> leading
> to situations where the core and MCU get out of sync and can't talk to each
> other.
>
Sounds good, I share this expectation, just wanted to check with you.
> >
> > > >
> > > > > These flags are there to indicate how to set rproc::sync_with_rproc
> > > > > after
> > > > > different events, that is when the remoteproc core boots, when the
> > > > > remoteproc
> > > > > has been stopped or when it has crashed.
> > > > >
> > > >
> > > > Right, that was clear from your patches. Sorry that my reply didn't
> > > > convey the information that I had understood this.
> > > >
> > > > > >
> > > > > > > +};
> > > > > > > +
> > > > > > > /**
> > > > > > > * struct rproc_ops - platform-specific device handlers
> > > > > > > * @start: power on the device and boot it
> > > > > > > @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> > > > > > > * @firmware: name of firmware file to be loaded
> > > > > > > * @priv: private data which belongs to the platform-specific
> > > > > > > rproc module
> > > > > > > * @ops: platform-specific start/stop rproc handlers
> > > > > > > + * @sync_ops: platform-specific start/stop rproc handlers when
> > > > > > > + * synchronising with a remote processor.
> > > > > > > + * @sync_flags: Determine the rproc_ops to choose in specific
> > > > > > > states.
> > > > > > > * @dev: virtual device for refcounting and common remoteproc
> > > > > > > behavior
> > > > > > > * @power: refcount of users who need this rproc powered up
> > > > > > > * @state: state of the device
> > > > > > > @@ -482,6 +502,7 @@ struct rproc_dump_segment {
> > > > > > > * @table_sz: size of @cached_table
> > > > > > > * @has_iommu: flag to indicate if remote processor is behind an
> > > > > > > MMU
> > > > > > > * @auto_boot: flag to indicate if remote processor should be
> > > > > > >
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Mon, May 18, 2020 at 05:55:00PM -0700, Bjorn Andersson wrote:
> On Fri 15 May 12:24 PDT 2020, Mathieu Poirier wrote:
>
> > Good day Bjorn,
> >
> > On Wed, May 13, 2020 at 06:32:24PM -0700, Bjorn Andersson wrote:
> > > On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
> > >
> > > > On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > > > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> > > > >
> > > > > > Add a new sync_ops to support use cases where the remoteproc
> > > > > > core is synchronising with the remote processor. Exactly when to
> > > > > > use
> > > > > > the synchronisation operations is directed by the flags in structure
> > > > > > rproc_sync_flags.
> > > > > >
> > > > >
> > > > > I'm sorry, but no matter how many times I read these patches I have to
> > > > > translate "synchronising" to "remote controlled", and given the number
> > > > > of comments clarifying this makes me feel that we could perhaps come
> > > > > up
> > > > > with a better name?
> > > >
> > > > "remote controlled" as in "someone else is managing the remote
> > > > processor" ?
> > > > It could also mean the remoteproc core is "remote controlling" the
> > > > remote processor, exactly what it currently does today...
> > > >
> > >
> > > You're right and this would certainly not help the confusion.
> > >
> > > > How about "autonomous", as in the remote processor doesn't need us to
> > > > boot or
> > > > switch it off. I'm open to any other suggestions.
> > > >
> > > > >
> > > > > > Signed-off-by: Mathieu Poirier
> > > > > > ---
> > > > > > include/linux/remoteproc.h | 24
> > > > > > 1 file changed, 24 insertions(+)
> > > > > >
> > > > > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > > > > index ac4082f12e8b..ceb3b2bba824 100644
> > > > > > --- a/include/linux/remoteproc.h
> > > > > > +++ b/include/linux/remoteproc.h
> > > > > > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > > > > > RSC_IGNORED = 1,
> > > > > > };
> > > > > >
> > > > > > +/**
> > > > > > + * struct rproc_sync_flags - platform specific flags indicating
> > > > > > which
> > > > > > + * rproc_ops to use at specific times during
> > > > > > + * the rproc lifecycle.
> > > > > > + * @on_init: true if synchronising with the remote processor at
> > > > > > + * initialisation time
> > > > > > + * @after_stop: true if synchronising with the remote processor
> > > > > > after it was
> > > > > > + * stopped from the cmmand line
> > > > > > + * @after_crash: true if synchronising with the remote processor
> > > > > > after
> > > > > > + * it has crashed
> > > > > > + */
> > > > > > +struct rproc_sync_flags {
> > > > > > + bool on_init;
> > > > >
> > > > > This indirectly splits the RPROC_OFFLINE state in an "offline" and
> > > > > "already-booted" state. Wouldn't it be clearer to represent this with
> > > > > a
> > > > > new RPROC_ALREADY_BOOTED state?
> > > > >
> > > >
> > > > I suggested that at some point in the past but it was in a different
> > > > context. I
> > > > will revisit to see how doing so could apply here.
> > > >
> > >
> > > How about we introduce a new state named DETACHED and make the platform
> > > drivers specify that the remote processor is in either OFFLINE (as
> > > today) or DETACHED during initialization.
> >
> > That is certainly an idea that is growing on me. Up to now I used the
> > on_init
> > flag to express duality in the OFFLINE state. But based on the comments
> > that came
> > back from yourself, Arnaud and Suman it is clear that my approach is
> > anything
> > but clear. As such I am eager to try something else.
> >
> > >
> > > Then on_init = true would be the action of going from DETACHED to
> > > RUNNING, which would involve the following actions:
> > >
> > > 1) find resource table
> > > 2) prepare device (?)
> > > 3) handle resources
> > > 4) allocate carveouts (?)
> > > 5) prepare subdevices
> > > 6) "attach"
> > > 7) start subdevices
> > >
> > > on_init = false would represent the transition from OFFLINE to RUNNING,
> > > which today involve the following actions:
> > >
> > > 1) request firmware
> > > 2) prepare device
> > > 3) parse fw
> > > 4) handle resources
> > > 5) allocate carveouts
> > > 6) load segments
> > > 7) find resource table
> > > 8) prepare subdevices
> > > 9) "boot"
> > > 10) start subdevices
> >
> > If we add a DETACHED state I don't see a scenario where we need the on_init
> > variable. When DETACHED is set by the platform we know the MCU is running
> > and
> > it becomes a matter of when the core attach to it, i.e at initialisation
> > time or
> > once the kernel has finished booting, and that is already taken care of by
> > the
> > auto_boot variable.
> >
> > The steps you have outlined above to describe the transitions are accurate.
> >
>
> Thanks for confirming.
>
> I think it would
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Fri 15 May 12:24 PDT 2020, Mathieu Poirier wrote:
> Good day Bjorn,
>
> On Wed, May 13, 2020 at 06:32:24PM -0700, Bjorn Andersson wrote:
> > On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
> >
> > > On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> > > >
> > > > > Add a new sync_ops to support use cases where the remoteproc
> > > > > core is synchronising with the remote processor. Exactly when to use
> > > > > the synchronisation operations is directed by the flags in structure
> > > > > rproc_sync_flags.
> > > > >
> > > >
> > > > I'm sorry, but no matter how many times I read these patches I have to
> > > > translate "synchronising" to "remote controlled", and given the number
> > > > of comments clarifying this makes me feel that we could perhaps come up
> > > > with a better name?
> > >
> > > "remote controlled" as in "someone else is managing the remote processor"
> > > ?
> > > It could also mean the remoteproc core is "remote controlling" the
> > > remote processor, exactly what it currently does today...
> > >
> >
> > You're right and this would certainly not help the confusion.
> >
> > > How about "autonomous", as in the remote processor doesn't need us to
> > > boot or
> > > switch it off. I'm open to any other suggestions.
> > >
> > > >
> > > > > Signed-off-by: Mathieu Poirier
> > > > > ---
> > > > > include/linux/remoteproc.h | 24
> > > > > 1 file changed, 24 insertions(+)
> > > > >
> > > > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > > > index ac4082f12e8b..ceb3b2bba824 100644
> > > > > --- a/include/linux/remoteproc.h
> > > > > +++ b/include/linux/remoteproc.h
> > > > > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > > > > RSC_IGNORED = 1,
> > > > > };
> > > > >
> > > > > +/**
> > > > > + * struct rproc_sync_flags - platform specific flags indicating which
> > > > > + * rproc_ops to use at specific times during
> > > > > + * the rproc lifecycle.
> > > > > + * @on_init: true if synchronising with the remote processor at
> > > > > + *initialisation time
> > > > > + * @after_stop: true if synchronising with the remote processor
> > > > > after it was
> > > > > + * stopped from the cmmand line
> > > > > + * @after_crash: true if synchronising with the remote processor
> > > > > after
> > > > > + *it has crashed
> > > > > + */
> > > > > +struct rproc_sync_flags {
> > > > > + bool on_init;
> > > >
> > > > This indirectly splits the RPROC_OFFLINE state in an "offline" and
> > > > "already-booted" state. Wouldn't it be clearer to represent this with a
> > > > new RPROC_ALREADY_BOOTED state?
> > > >
> > >
> > > I suggested that at some point in the past but it was in a different
> > > context. I
> > > will revisit to see how doing so could apply here.
> > >
> >
> > How about we introduce a new state named DETACHED and make the platform
> > drivers specify that the remote processor is in either OFFLINE (as
> > today) or DETACHED during initialization.
>
> That is certainly an idea that is growing on me. Up to now I used the on_init
> flag to express duality in the OFFLINE state. But based on the comments that
> came
> back from yourself, Arnaud and Suman it is clear that my approach is anything
> but clear. As such I am eager to try something else.
>
> >
> > Then on_init = true would be the action of going from DETACHED to
> > RUNNING, which would involve the following actions:
> >
> > 1) find resource table
> > 2) prepare device (?)
> > 3) handle resources
> > 4) allocate carveouts (?)
> > 5) prepare subdevices
> > 6) "attach"
> > 7) start subdevices
> >
> > on_init = false would represent the transition from OFFLINE to RUNNING,
> > which today involve the following actions:
> >
> > 1) request firmware
> > 2) prepare device
> > 3) parse fw
> > 4) handle resources
> > 5) allocate carveouts
> > 6) load segments
> > 7) find resource table
> > 8) prepare subdevices
> > 9) "boot"
> > 10) start subdevices
>
> If we add a DETACHED state I don't see a scenario where we need the on_init
> variable. When DETACHED is set by the platform we know the MCU is running and
> it becomes a matter of when the core attach to it, i.e at initialisation time
> or
> once the kernel has finished booting, and that is already taken care of by the
> auto_boot variable.
>
> The steps you have outlined above to describe the transitions are accurate.
>
Thanks for confirming.
I think it would be helpful if we had this properly documented in the
driver, to facilitate reasoning about the various transitions. I'll try
to write down my notes in a patch and send it out.
> >
> > > > > + bool after_stop;
> > > >
> > > > What does it mean when this is true? That Linux can shut the remote core
> > > > down, but someone else will start it?
> > >
> > >
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
Good day Bjorn,
On Wed, May 13, 2020 at 06:32:24PM -0700, Bjorn Andersson wrote:
> On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
>
> > On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> > >
> > > > Add a new sync_ops to support use cases where the remoteproc
> > > > core is synchronising with the remote processor. Exactly when to use
> > > > the synchronisation operations is directed by the flags in structure
> > > > rproc_sync_flags.
> > > >
> > >
> > > I'm sorry, but no matter how many times I read these patches I have to
> > > translate "synchronising" to "remote controlled", and given the number
> > > of comments clarifying this makes me feel that we could perhaps come up
> > > with a better name?
> >
> > "remote controlled" as in "someone else is managing the remote processor" ?
> > It could also mean the remoteproc core is "remote controlling" the
> > remote processor, exactly what it currently does today...
> >
>
> You're right and this would certainly not help the confusion.
>
> > How about "autonomous", as in the remote processor doesn't need us to boot
> > or
> > switch it off. I'm open to any other suggestions.
> >
> > >
> > > > Signed-off-by: Mathieu Poirier
> > > > ---
> > > > include/linux/remoteproc.h | 24
> > > > 1 file changed, 24 insertions(+)
> > > >
> > > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > > index ac4082f12e8b..ceb3b2bba824 100644
> > > > --- a/include/linux/remoteproc.h
> > > > +++ b/include/linux/remoteproc.h
> > > > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > > > RSC_IGNORED = 1,
> > > > };
> > > >
> > > > +/**
> > > > + * struct rproc_sync_flags - platform specific flags indicating which
> > > > + * rproc_ops to use at specific times during
> > > > + * the rproc lifecycle.
> > > > + * @on_init: true if synchronising with the remote processor at
> > > > + * initialisation time
> > > > + * @after_stop: true if synchronising with the remote processor after
> > > > it was
> > > > + * stopped from the cmmand line
> > > > + * @after_crash: true if synchronising with the remote processor after
> > > > + * it has crashed
> > > > + */
> > > > +struct rproc_sync_flags {
> > > > + bool on_init;
> > >
> > > This indirectly splits the RPROC_OFFLINE state in an "offline" and
> > > "already-booted" state. Wouldn't it be clearer to represent this with a
> > > new RPROC_ALREADY_BOOTED state?
> > >
> >
> > I suggested that at some point in the past but it was in a different
> > context. I
> > will revisit to see how doing so could apply here.
> >
>
> How about we introduce a new state named DETACHED and make the platform
> drivers specify that the remote processor is in either OFFLINE (as
> today) or DETACHED during initialization.
That is certainly an idea that is growing on me. Up to now I used the on_init
flag to express duality in the OFFLINE state. But based on the comments that
came
back from yourself, Arnaud and Suman it is clear that my approach is anything
but clear. As such I am eager to try something else.
>
> Then on_init = true would be the action of going from DETACHED to
> RUNNING, which would involve the following actions:
>
> 1) find resource table
> 2) prepare device (?)
> 3) handle resources
> 4) allocate carveouts (?)
> 5) prepare subdevices
> 6) "attach"
> 7) start subdevices
>
> on_init = false would represent the transition from OFFLINE to RUNNING,
> which today involve the following actions:
>
> 1) request firmware
> 2) prepare device
> 3) parse fw
> 4) handle resources
> 5) allocate carveouts
> 6) load segments
> 7) find resource table
> 8) prepare subdevices
> 9) "boot"
> 10) start subdevices
If we add a DETACHED state I don't see a scenario where we need the on_init
variable. When DETACHED is set by the platform we know the MCU is running and
it becomes a matter of when the core attach to it, i.e at initialisation time or
once the kernel has finished booting, and that is already taken care of by the
auto_boot variable.
The steps you have outlined above to describe the transitions are accurate.
>
> > > > + bool after_stop;
> > >
> > > What does it mean when this is true? That Linux can shut the remote core
> > > down, but someone else will start it?
> >
> > It tells the remoteproc core how to interact with the remote processor
> > after the
> > latter has been switched off.
>
> Understood.
>
> > For example, we could want to boot the remote
> > processor from the boot loader so that minimal functionality can be provided
> > while the kernel boots. Once the kernel and user space are in place, the
> > remote
> > processor is explicitly stopped and booted once again, but this time with a
> > firmware image that offers full functionality.
> >
>
> This would be
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Fri 08 May 14:01 PDT 2020, Mathieu Poirier wrote:
> On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> > On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> >
> > > Add a new sync_ops to support use cases where the remoteproc
> > > core is synchronising with the remote processor. Exactly when to use
> > > the synchronisation operations is directed by the flags in structure
> > > rproc_sync_flags.
> > >
> >
> > I'm sorry, but no matter how many times I read these patches I have to
> > translate "synchronising" to "remote controlled", and given the number
> > of comments clarifying this makes me feel that we could perhaps come up
> > with a better name?
>
> "remote controlled" as in "someone else is managing the remote processor" ?
> It could also mean the remoteproc core is "remote controlling" the
> remote processor, exactly what it currently does today...
>
You're right and this would certainly not help the confusion.
> How about "autonomous", as in the remote processor doesn't need us to boot or
> switch it off. I'm open to any other suggestions.
>
> >
> > > Signed-off-by: Mathieu Poirier
> > > ---
> > > include/linux/remoteproc.h | 24
> > > 1 file changed, 24 insertions(+)
> > >
> > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > index ac4082f12e8b..ceb3b2bba824 100644
> > > --- a/include/linux/remoteproc.h
> > > +++ b/include/linux/remoteproc.h
> > > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > > RSC_IGNORED = 1,
> > > };
> > >
> > > +/**
> > > + * struct rproc_sync_flags - platform specific flags indicating which
> > > + * rproc_ops to use at specific times during
> > > + * the rproc lifecycle.
> > > + * @on_init: true if synchronising with the remote processor at
> > > + *initialisation time
> > > + * @after_stop: true if synchronising with the remote processor after it
> > > was
> > > + * stopped from the cmmand line
> > > + * @after_crash: true if synchronising with the remote processor after
> > > + *it has crashed
> > > + */
> > > +struct rproc_sync_flags {
> > > + bool on_init;
> >
> > This indirectly splits the RPROC_OFFLINE state in an "offline" and
> > "already-booted" state. Wouldn't it be clearer to represent this with a
> > new RPROC_ALREADY_BOOTED state?
> >
>
> I suggested that at some point in the past but it was in a different context.
> I
> will revisit to see how doing so could apply here.
>
How about we introduce a new state named DETACHED and make the platform
drivers specify that the remote processor is in either OFFLINE (as
today) or DETACHED during initialization.
Then on_init = true would be the action of going from DETACHED to
RUNNING, which would involve the following actions:
1) find resource table
2) prepare device (?)
3) handle resources
4) allocate carveouts (?)
5) prepare subdevices
6) "attach"
7) start subdevices
on_init = false would represent the transition from OFFLINE to RUNNING,
which today involve the following actions:
1) request firmware
2) prepare device
3) parse fw
4) handle resources
5) allocate carveouts
6) load segments
7) find resource table
8) prepare subdevices
9) "boot"
10) start subdevices
> > > + bool after_stop;
> >
> > What does it mean when this is true? That Linux can shut the remote core
> > down, but someone else will start it?
>
> It tells the remoteproc core how to interact with the remote processor after
> the
> latter has been switched off.
Understood.
> For example, we could want to boot the remote
> processor from the boot loader so that minimal functionality can be provided
> while the kernel boots. Once the kernel and user space are in place, the
> remote
> processor is explicitly stopped and booted once again, but this time with a
> firmware image that offers full functionality.
>
This would be the { on_init = true, after_stop = false } use case, with
the new state would relate to the journey of DETACHED -> RUNNING ->
OFFLINE.
As such the next boot would represent above OFFLINE -> RUNNING case,
which we already support today.
> It could also be that the remoteproc core can stop the remote processor, but
> the
> remote processor will automatically reboot itself. In that case the
> remoteproc
> core will simply synchronise with the remote processor, as it does when
> .on_init
> == true.
>
I've not been able to come up with a reasonable use case for the {
on_init = ture, after_stop = true } scenario.
But Wendy previously talked about the need to "detach" Linux from a
running remote processor, by somehow just letting it know that the
communication is down - to allow Linux to be rebooted while the remote
was running. So if we support a transition from RUNNING to DETACHED
using a sequence of something like:
1) stop subdevices
2) "detach"
3) unprepare subdevices
4) release carveouts (?)
5) unprepare device
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Tue, May 05, 2020 at 05:22:53PM -0700, Bjorn Andersson wrote:
> On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
>
> > Add a new sync_ops to support use cases where the remoteproc
> > core is synchronising with the remote processor. Exactly when to use
> > the synchronisation operations is directed by the flags in structure
> > rproc_sync_flags.
> >
>
> I'm sorry, but no matter how many times I read these patches I have to
> translate "synchronising" to "remote controlled", and given the number
> of comments clarifying this makes me feel that we could perhaps come up
> with a better name?
"remote controlled" as in "someone else is managing the remote processor" ? It
could also mean the remoteproc core is "remote controlling" the remote
processor, exactly what it currently does today...
How about "autonomous", as in the remote processor doesn't need us to boot or
switch it off. I'm open to any other suggestions.
>
> > Signed-off-by: Mathieu Poirier
> > ---
> > include/linux/remoteproc.h | 24
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > index ac4082f12e8b..ceb3b2bba824 100644
> > --- a/include/linux/remoteproc.h
> > +++ b/include/linux/remoteproc.h
> > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > RSC_IGNORED = 1,
> > };
> >
> > +/**
> > + * struct rproc_sync_flags - platform specific flags indicating which
> > + * rproc_ops to use at specific times during
> > + * the rproc lifecycle.
> > + * @on_init: true if synchronising with the remote processor at
> > + * initialisation time
> > + * @after_stop: true if synchronising with the remote processor after it
> > was
> > + * stopped from the cmmand line
> > + * @after_crash: true if synchronising with the remote processor after
> > + * it has crashed
> > + */
> > +struct rproc_sync_flags {
> > + bool on_init;
>
> This indirectly splits the RPROC_OFFLINE state in an "offline" and
> "already-booted" state. Wouldn't it be clearer to represent this with a
> new RPROC_ALREADY_BOOTED state?
>
I suggested that at some point in the past but it was in a different context. I
will revisit to see how doing so could apply here.
> > + bool after_stop;
>
> What does it mean when this is true? That Linux can shut the remote core
> down, but someone else will start it?
It tells the remoteproc core how to interact with the remote processor after the
latter has been switched off. For example, we could want to boot the remote
processor from the boot loader so that minimal functionality can be provided
while the kernel boots. Once the kernel and user space are in place, the remote
processor is explicitly stopped and booted once again, but this time with a
firmware image that offers full functionality.
It could also be that the remoteproc core can stop the remote processor, but the
remote processor will automatically reboot itself. In that case the remoteproc
core will simply synchronise with the remote processor, as it does when .on_init
== true.
>
> > + bool after_crash;
>
> Similarly what is the expected steps to be taken by the core when this
> is true? Should rproc_report_crash() simply stop/start the subdevices
> and upon one of the ops somehow tell the remote controller that it can
> proceed with the recovery?
The exact same sequence of steps will be carried out as they are today, except
that if after_crash == true, the remoteproc core won't be switching the remote
processor on, exactly as it would do when on_init == true.
These flags are there to indicate how to set rproc::sync_with_rproc after
different events, that is when the remoteproc core boots, when the remoteproc
has been stopped or when it has crashed.
>
> > +};
> > +
> > /**
> > * struct rproc_ops - platform-specific device handlers
> > * @start: power on the device and boot it
> > @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> > * @firmware: name of firmware file to be loaded
> > * @priv: private data which belongs to the platform-specific rproc module
> > * @ops: platform-specific start/stop rproc handlers
> > + * @sync_ops: platform-specific start/stop rproc handlers when
> > + * synchronising with a remote processor.
> > + * @sync_flags: Determine the rproc_ops to choose in specific states.
> > * @dev: virtual device for refcounting and common remoteproc behavior
> > * @power: refcount of users who need this rproc powered up
> > * @state: state of the device
> > @@ -482,6 +502,7 @@ struct rproc_dump_segment {
> > * @table_sz: size of @cached_table
> > * @has_iommu: flag to indicate if remote processor is behind an MMU
> > * @auto_boot: flag to indicate if remote processor should be auto-started
> > + * @sync_with_rproc: true if currently synchronising with the rproc
> > * @dump_segments: list of segments in the firmware
> > * @nb_vdev: number of vdev
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> Add a new sync_ops to support use cases where the remoteproc
> core is synchronising with the remote processor. Exactly when to use
> the synchronisation operations is directed by the flags in structure
> rproc_sync_flags.
>
I'm sorry, but no matter how many times I read these patches I have to
translate "synchronising" to "remote controlled", and given the number
of comments clarifying this makes me feel that we could perhaps come up
with a better name?
> Signed-off-by: Mathieu Poirier
> ---
> include/linux/remoteproc.h | 24
> 1 file changed, 24 insertions(+)
>
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index ac4082f12e8b..ceb3b2bba824 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -353,6 +353,23 @@ enum rsc_handling_status {
> RSC_IGNORED = 1,
> };
>
> +/**
> + * struct rproc_sync_flags - platform specific flags indicating which
> + * rproc_ops to use at specific times during
> + * the rproc lifecycle.
> + * @on_init: true if synchronising with the remote processor at
> + *initialisation time
> + * @after_stop: true if synchronising with the remote processor after it was
> + * stopped from the cmmand line
> + * @after_crash: true if synchronising with the remote processor after
> + *it has crashed
> + */
> +struct rproc_sync_flags {
> + bool on_init;
This indirectly splits the RPROC_OFFLINE state in an "offline" and
"already-booted" state. Wouldn't it be clearer to represent this with a
new RPROC_ALREADY_BOOTED state?
> + bool after_stop;
What does it mean when this is true? That Linux can shut the remote core
down, but someone else will start it?
> + bool after_crash;
Similarly what is the expected steps to be taken by the core when this
is true? Should rproc_report_crash() simply stop/start the subdevices
and upon one of the ops somehow tell the remote controller that it can
proceed with the recovery?
> +};
> +
> /**
> * struct rproc_ops - platform-specific device handlers
> * @start: power on the device and boot it
> @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> * @firmware: name of firmware file to be loaded
> * @priv: private data which belongs to the platform-specific rproc module
> * @ops: platform-specific start/stop rproc handlers
> + * @sync_ops: platform-specific start/stop rproc handlers when
> + * synchronising with a remote processor.
> + * @sync_flags: Determine the rproc_ops to choose in specific states.
> * @dev: virtual device for refcounting and common remoteproc behavior
> * @power: refcount of users who need this rproc powered up
> * @state: state of the device
> @@ -482,6 +502,7 @@ struct rproc_dump_segment {
> * @table_sz: size of @cached_table
> * @has_iommu: flag to indicate if remote processor is behind an MMU
> * @auto_boot: flag to indicate if remote processor should be auto-started
> + * @sync_with_rproc: true if currently synchronising with the rproc
> * @dump_segments: list of segments in the firmware
> * @nb_vdev: number of vdev currently handled by rproc
> */
> @@ -492,6 +513,8 @@ struct rproc {
> const char *firmware;
> void *priv;
> struct rproc_ops *ops;
> + struct rproc_ops *sync_ops;
Do we really need two rproc_ops, given that both are coming from the
platform driver and the sync_flags will define which one to look at?
Can't the platform driver just provide an ops table that works with the
flags it passes?
Regards,
Bjorn
> + struct rproc_sync_flags sync_flags;
> struct device dev;
> atomic_t power;
> unsigned int state;
> @@ -515,6 +538,7 @@ struct rproc {
> size_t table_sz;
> bool has_iommu;
> bool auto_boot;
> + bool sync_with_rproc;
> struct list_head dump_segments;
> int nb_vdev;
> u8 elf_class;
> --
> 2.20.1
>
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On Tue, Apr 28, 2020 at 06:38:41PM +0200, Arnaud POULIQUEN wrote:
>
>
> On 4/24/20 10:01 PM, Mathieu Poirier wrote:
> > Add a new sync_ops to support use cases where the remoteproc
> > core is synchronising with the remote processor. Exactly when to use
> > the synchronisation operations is directed by the flags in structure
> > rproc_sync_flags.
> >
> > Signed-off-by: Mathieu Poirier
> > ---
> > include/linux/remoteproc.h | 24
> > 1 file changed, 24 insertions(+)
> >
> > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > index ac4082f12e8b..ceb3b2bba824 100644
> > --- a/include/linux/remoteproc.h
> > +++ b/include/linux/remoteproc.h
> > @@ -353,6 +353,23 @@ enum rsc_handling_status {
> > RSC_IGNORED = 1,
> > };
> >
> > +/**
> > + * struct rproc_sync_flags - platform specific flags indicating which
> > + * rproc_ops to use at specific times during
> > + * the rproc lifecycle.
> > + * @on_init: true if synchronising with the remote processor at
> > + * initialisation time
> > + * @after_stop: true if synchronising with the remote processor after it
> > was
> > + * stopped from the cmmand line
> typo command
> > + * @after_crash: true if synchronising with the remote processor after
> > + * it has crashed
> > + */
> > +struct rproc_sync_flags {
> > + bool on_init;
> > + bool after_stop;
> > + bool after_crash;
> > +};
> > +
> how about a bit field instead (just a proposition)?
> Platform driver would set the sync flag and rproc_set_sync_flag could be a
> simple mask instead of a switch case.
I opted for a structure over bit fields because I thought it would be easier to
read/understand. Both approaches are valid and I have to particular preference
other than, in my own view, a structure is easier to understand.
I'll wait a little to see what other people think. If nobody objects the next
revision will have bit fields.
>
> Is it possible to split this patch in a different ways because difficult to
> understand as
> rproc_sync_flags seems not used before
> [PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing
Certainly
>
> Thanks
> Arnaud
>
> > /**
> > * struct rproc_ops - platform-specific device handlers
> > * @start: power on the device and boot it
> > @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> > * @firmware: name of firmware file to be loaded
> > * @priv: private data which belongs to the platform-specific rproc module
> > * @ops: platform-specific start/stop rproc handlers
> > + * @sync_ops: platform-specific start/stop rproc handlers when
> > + * synchronising with a remote processor.
> > + * @sync_flags: Determine the rproc_ops to choose in specific states.
> > * @dev: virtual device for refcounting and common remoteproc behavior
> > * @power: refcount of users who need this rproc powered up
> > * @state: state of the device
> > @@ -482,6 +502,7 @@ struct rproc_dump_segment {
> > * @table_sz: size of @cached_table
> > * @has_iommu: flag to indicate if remote processor is behind an MMU
> > * @auto_boot: flag to indicate if remote processor should be auto-started
> > + * @sync_with_rproc: true if currently synchronising with the rproc
> > * @dump_segments: list of segments in the firmware
> > * @nb_vdev: number of vdev currently handled by rproc
> > */
> > @@ -492,6 +513,8 @@ struct rproc {
> > const char *firmware;
> > void *priv;
> > struct rproc_ops *ops;
> > + struct rproc_ops *sync_ops;
> > + struct rproc_sync_flags sync_flags;
> > struct device dev;
> > atomic_t power;
> > unsigned int state;
> > @@ -515,6 +538,7 @@ struct rproc {
> > size_t table_sz;
> > bool has_iommu;
> > bool auto_boot;
> > + bool sync_with_rproc;
> > struct list_head dump_segments;
> > int nb_vdev;
> > u8 elf_class;
> >
Re: [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation
On 4/24/20 10:01 PM, Mathieu Poirier wrote:
> Add a new sync_ops to support use cases where the remoteproc
> core is synchronising with the remote processor. Exactly when to use
> the synchronisation operations is directed by the flags in structure
> rproc_sync_flags.
>
> Signed-off-by: Mathieu Poirier
> ---
> include/linux/remoteproc.h | 24
> 1 file changed, 24 insertions(+)
>
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index ac4082f12e8b..ceb3b2bba824 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -353,6 +353,23 @@ enum rsc_handling_status {
> RSC_IGNORED = 1,
> };
>
> +/**
> + * struct rproc_sync_flags - platform specific flags indicating which
> + * rproc_ops to use at specific times during
> + * the rproc lifecycle.
> + * @on_init: true if synchronising with the remote processor at
> + *initialisation time
> + * @after_stop: true if synchronising with the remote processor after it was
> + * stopped from the cmmand line
typo command
> + * @after_crash: true if synchronising with the remote processor after
> + *it has crashed
> + */
> +struct rproc_sync_flags {
> + bool on_init;
> + bool after_stop;
> + bool after_crash;
> +};
> +
how about a bit field instead (just a proposition)?
Platform driver would set the sync flag and rproc_set_sync_flag could be a
simple mask instead of a switch case.
Is it possible to split this patch in a different ways because difficult to
understand as
rproc_sync_flags seems not used before
[PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing
Thanks
Arnaud
> /**
> * struct rproc_ops - platform-specific device handlers
> * @start: power on the device and boot it
> @@ -459,6 +476,9 @@ struct rproc_dump_segment {
> * @firmware: name of firmware file to be loaded
> * @priv: private data which belongs to the platform-specific rproc module
> * @ops: platform-specific start/stop rproc handlers
> + * @sync_ops: platform-specific start/stop rproc handlers when
> + * synchronising with a remote processor.
> + * @sync_flags: Determine the rproc_ops to choose in specific states.
> * @dev: virtual device for refcounting and common remoteproc behavior
> * @power: refcount of users who need this rproc powered up
> * @state: state of the device
> @@ -482,6 +502,7 @@ struct rproc_dump_segment {
> * @table_sz: size of @cached_table
> * @has_iommu: flag to indicate if remote processor is behind an MMU
> * @auto_boot: flag to indicate if remote processor should be auto-started
> + * @sync_with_rproc: true if currently synchronising with the rproc
> * @dump_segments: list of segments in the firmware
> * @nb_vdev: number of vdev currently handled by rproc
> */
> @@ -492,6 +513,8 @@ struct rproc {
> const char *firmware;
> void *priv;
> struct rproc_ops *ops;
> + struct rproc_ops *sync_ops;
> + struct rproc_sync_flags sync_flags;
> struct device dev;
> atomic_t power;
> unsigned int state;
> @@ -515,6 +538,7 @@ struct rproc {
> size_t table_sz;
> bool has_iommu;
> bool auto_boot;
> + bool sync_with_rproc;
> struct list_head dump_segments;
> int nb_vdev;
> u8 elf_class;
>
