From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: Arnaud POULIQUEN <arnaud.pouliquen@st.com>
Cc: bjorn.andersson@linaro.org, ohad@wizery.com,
loic.pallardy@st.com, s-anna@ti.com,
linux-remoteproc@vger.kernel.org, corbet@lwn.net,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 10/14] remoteproc: Deal with synchronisation when shutting down
Date: Tue, 5 May 2020 16:03:27 -0600 [thread overview]
Message-ID: <20200505220327.GB18333@xps15> (raw)
In-Reply-To: <04b8f860-2b01-7e4f-cdea-08a3cf8af26c@st.com>
On Mon, May 04, 2020 at 01:34:43PM +0200, Arnaud POULIQUEN wrote:
>
>
> On 4/30/20 10:23 PM, Mathieu Poirier wrote:
> > On Wed, Apr 29, 2020 at 10:19:49AM +0200, Arnaud POULIQUEN wrote:
> >>
> >>
> >> On 4/24/20 10:01 PM, Mathieu Poirier wrote:
> >>> The remoteproc core must not allow function rproc_shutdown() to
> >>> proceed if currently synchronising with a remote processor and
> >>> the synchronisation operations of that remote processor does not
> >>> support it. Also part of the process is to set the synchronisation
> >>> flag so that the remoteproc core can make the right decisions when
> >>> restarting the system.
> >>>
> >>> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> >>> ---
> >>> drivers/remoteproc/remoteproc_core.c | 32 ++++++++++++++++++++++++
> >>> drivers/remoteproc/remoteproc_internal.h | 7 ++++++
> >>> 2 files changed, 39 insertions(+)
> >>>
> >>> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> >>> index 3a84a38ba37b..48afa1f80a8f 100644
> >>> --- a/drivers/remoteproc/remoteproc_core.c
> >>> +++ b/drivers/remoteproc/remoteproc_core.c
> >>> @@ -1849,6 +1849,27 @@ int rproc_boot(struct rproc *rproc)
> >>> }
> >>> EXPORT_SYMBOL(rproc_boot);
> >>>
> >>> +static bool rproc_can_shutdown(struct rproc *rproc)
> >>> +{
> >>> + /*
> >>> + * The remoteproc core is the lifecycle manager, no problem
> >>> + * calling for a shutdown.
> >>> + */
> >>> + if (!rproc_needs_syncing(rproc))
> >>> + return true;
> >>> +
> >>> + /*
> >>> + * The remoteproc has been loaded by another entity (as per above
> >>> + * condition) and the platform code has given us the capability
> >>> + * of stopping it.
> >>> + */
> >>> + if (rproc->sync_ops->stop)
> >>> + return true;
> >>
> >> This means that if rproc->sync_ops->stop is null rproc_stop_subdevices will not
> >> be called? seems not symmetric with the start sequence.
> >
> > If rproc->sync_ops->stop is not provided then the remoteproc core can't stop the
> > remote processor at all after it has synchronised with it. If a usecase
> > requires some kind of soft reset then a stop() function that uses a mailbox
> > notification or some other mechanism can be provided to tell the remote
> > processor to put itself back in startup mode again.
> >
> > Is this fine with you or there is still something I don't get?
>
> My point here is more around the subdevices. But perhaps i missed something...
>
> In rproc_start rproc_start_subdevices is called, even if sync_start is null.
Here I'll take that you mean sync_ops::start()
> But in rproc_shutdown rproc_stop is not called, if sync_ops->stop is null.
> So rproc_stop_subdevices is not called in this case.
Correct. I am pretty sure some people don't want the remoteproc core to be able
to do anything other than synchronise with a remote processor, be it at boot
time or when the remote processor has crashed.
I can also see scenarios where people want to be able to start and stop
subdevices from the remoteproc core, but _not_ power cycle the remote processor.
In such cases the sync_ops::stop() should be some kind of notification telling
the remote processor to put itself back in initialisation mode and
sync_flags.after_stop should be set to true.
> Then if sync_flags.after_stop is false, it looks like that something will go wrong
> at next start.
If sync_ops::stop is NULL then the value of sync_flags.after_stop becomes
irrelevant because that state can't be reached. Let me know if you found a
condition where this isn't the case and I will correct it.
>
> >
> >> Probably not useful to test it here as condition is already handled in rproc_stop_device...
> >>
> >> Regards
> >> Arnaud
> >>> +
> >>> + /* Any other condition should not be allowed */
> >>> + return false;
> >>> +}
> >>> +
> >>> /**
> >>> * rproc_shutdown() - power off the remote processor
> >>> * @rproc: the remote processor
> >>> @@ -1879,6 +1900,9 @@ void rproc_shutdown(struct rproc *rproc)
> >>> return;
> >>> }
> >>>
> >>> + if (!rproc_can_shutdown(rproc))
> >>> + goto out;
> >>> +
> >>> /* if the remote proc is still needed, bail out */
> >>> if (!atomic_dec_and_test(&rproc->power))
> >>> goto out;
> >>> @@ -1898,6 +1922,14 @@ void rproc_shutdown(struct rproc *rproc)
> >>> kfree(rproc->cached_table);
> >>> rproc->cached_table = NULL;
> >>> rproc->table_ptr = NULL;
> >>> +
> >>> + /*
> >>> + * The remote processor has been switched off - tell the core what
> >>> + * operation to use from hereon, i.e whether an external entity will
> >>> + * reboot the remote processor or it is now the remoteproc core's
> >>> + * responsability.
> >>> + */
> >>> + rproc_set_sync_flag(rproc, RPROC_SYNC_STATE_SHUTDOWN);
> >>> out:
> >>> mutex_unlock(&rproc->lock);
> >>> }
> >>> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> >>> index 61500981155c..7dcc0a26892b 100644
> >>> --- a/drivers/remoteproc/remoteproc_internal.h
> >>> +++ b/drivers/remoteproc/remoteproc_internal.h
> >>> @@ -27,6 +27,9 @@ struct rproc_debug_trace {
> >>> /*
> >>> * enum rproc_sync_states - remote processsor sync states
> >>> *
> >>> + * @RPROC_SYNC_STATE_SHUTDOWN state to use after the remoteproc core
> >>> + * has shutdown (rproc_shutdown()) the
> >>> + * remote processor.
> >>> * @RPROC_SYNC_STATE_CRASHED state to use after the remote processor
> >>> * has crashed but has not been recovered by
> >>> * the remoteproc core yet.
> >>> @@ -36,6 +39,7 @@ struct rproc_debug_trace {
> >>> * operation to use.
> >>> */
> >>> enum rproc_sync_states {
> >>> + RPROC_SYNC_STATE_SHUTDOWN,
> >>> RPROC_SYNC_STATE_CRASHED,
> >>> };
> >>>
> >>> @@ -43,6 +47,9 @@ static inline void rproc_set_sync_flag(struct rproc *rproc,
> >>> enum rproc_sync_states state)
> >>> {
> >>> switch (state) {
> >>> + case RPROC_SYNC_STATE_SHUTDOWN:
> >>> + rproc->sync_with_rproc = rproc->sync_flags.after_stop;
> >>> + break;
> >>> case RPROC_SYNC_STATE_CRASHED:
> >>> rproc->sync_with_rproc = rproc->sync_flags.after_crash;
> >>> break;
> >>>
next prev parent reply other threads:[~2020-05-05 22:03 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-24 20:01 [PATCH v3 00/14] remoteproc: Add support for synchronisaton with rproc Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 01/14] remoteproc: Make core operations optional Mathieu Poirier
2020-04-28 16:18 ` Arnaud POULIQUEN
2020-04-30 19:39 ` Mathieu Poirier
2020-05-05 22:16 ` Bjorn Andersson
2020-05-08 19:09 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 02/14] remoteproc: Introduce function rproc_alloc_internals() Mathieu Poirier
2020-05-05 22:31 ` Bjorn Andersson
2020-05-08 19:37 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 03/14] remoteproc: Add new operation and flags for synchronistation Mathieu Poirier
2020-04-28 16:38 ` Arnaud POULIQUEN
2020-04-30 19:49 ` Mathieu Poirier
2020-05-06 0:22 ` Bjorn Andersson
2020-05-08 21:01 ` Mathieu Poirier
2020-05-14 1:32 ` Bjorn Andersson
2020-05-15 19:24 ` Mathieu Poirier
2020-05-19 0:55 ` Bjorn Andersson
2020-05-20 22:06 ` Mathieu Poirier
2020-05-21 5:21 ` Bjorn Andersson
2020-05-21 21:55 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 04/14] remoteproc: Refactor function rproc_boot() Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 05/14] remoteproc: Refactor function rproc_fw_boot() Mathieu Poirier
2020-05-06 0:33 ` Bjorn Andersson
2020-05-08 21:27 ` Mathieu Poirier
2020-05-14 2:10 ` Bjorn Andersson
2020-05-15 19:46 ` Mathieu Poirier
2020-05-19 0:22 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 06/14] remoteproc: Refactor function rproc_trigger_auto_boot() Mathieu Poirier
2020-04-28 17:00 ` Arnaud POULIQUEN
2020-04-24 20:01 ` [PATCH v3 07/14] remoteproc: Introducting new start and stop functions Mathieu Poirier
2020-05-06 0:42 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 08/14] remoteproc: Call core functions based on synchronisation flag Mathieu Poirier
2020-04-28 17:27 ` Arnaud POULIQUEN
2020-04-30 19:57 ` Mathieu Poirier
2020-05-04 11:14 ` Arnaud POULIQUEN
2020-05-05 22:10 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 09/14] remoteproc: Deal with synchronisation when crashing Mathieu Poirier
2020-04-29 7:44 ` Arnaud POULIQUEN
2020-04-30 20:11 ` Mathieu Poirier
2020-05-06 1:01 ` Bjorn Andersson
2020-05-08 21:47 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 10/14] remoteproc: Deal with synchronisation when shutting down Mathieu Poirier
2020-04-29 8:19 ` Arnaud POULIQUEN
2020-04-30 20:23 ` Mathieu Poirier
2020-05-04 11:34 ` Arnaud POULIQUEN
2020-05-05 22:03 ` Mathieu Poirier [this message]
2020-05-06 7:51 ` Arnaud POULIQUEN
2020-05-06 1:10 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 11/14] remoteproc: Deal with synchronisation when changing FW image Mathieu Poirier
2020-04-29 8:52 ` Arnaud POULIQUEN
2020-04-30 20:32 ` Mathieu Poirier
2020-05-06 1:27 ` Bjorn Andersson
2020-04-24 20:01 ` [PATCH v3 12/14] remoteproc: Introducing function rproc_set_state_machine() Mathieu Poirier
2020-04-29 9:22 ` Arnaud POULIQUEN
2020-04-29 14:38 ` Arnaud POULIQUEN
2020-04-30 20:51 ` Mathieu Poirier
2020-05-04 12:00 ` Arnaud POULIQUEN
2020-04-30 20:42 ` Mathieu Poirier
2020-05-04 11:57 ` Arnaud POULIQUEN
2020-05-05 21:43 ` Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 13/14] remoteproc: Document " Mathieu Poirier
2020-04-24 20:01 ` [PATCH v3 14/14] remoteproc: Expose synchronisation flags via debugfs Mathieu Poirier
2020-05-18 13:28 ` [PATCH v3 00/14] remoteproc: Add support for synchronisaton with rproc Peng Fan
2020-05-18 16:29 ` Mathieu Poirier
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