Re: [PATCH v3 12/14] remoteproc: Introducing function rproc_set_state_machine()

Mathieu Poirier
2020-04-30T20:51:47Z

On Wed, Apr 29, 2020 at 04:38:54PM +0200, Arnaud POULIQUEN wrote:
>
>
> On 4/29/20 11:22 AM, Arnaud POULIQUEN wrote:
> >
> >
> > On 4/24/20 10:01 PM, Mathieu Poirier wrote:
> >> Introducting function rproc_set_state_machine() to add
> >> operations and a set of flags to use when synchronising with
> >> a remote processor.
> >>
> >> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
> >> ---
> >> drivers/remoteproc/remoteproc_core.c | 54 ++++++++++++++++++++++++
> >> drivers/remoteproc/remoteproc_internal.h | 6 +++
> >> include/linux/remoteproc.h | 3 ++
> >> 3 files changed, 63 insertions(+)
> >>
> >> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> >> index 48afa1f80a8f..5c48714e8702 100644
> >> --- a/drivers/remoteproc/remoteproc_core.c
> >> +++ b/drivers/remoteproc/remoteproc_core.c
> >> @@ -2065,6 +2065,59 @@ int devm_rproc_add(struct device *dev, struct rproc *rproc)
> >> }
> >> EXPORT_SYMBOL(devm_rproc_add);
> >>
> >> +/**
> >> + * rproc_set_state_machine() - Set a synchronisation ops and set of flags
> >> + * to use with a remote processor
> >> + * @rproc: The remote processor to work with
> >> + * @sync_ops: The operations to use when synchronising with a remote
> >> + * processor
> >> + * @sync_flags: The flags to use when deciding if the remoteproc core
> >> + * should be synchronising with a remote processor
> >> + *
> >> + * Returns 0 on success, an error code otherwise.
> >> + */
> >> +int rproc_set_state_machine(struct rproc *rproc,
> >> + const struct rproc_ops *sync_ops,
> >> + struct rproc_sync_flags sync_flags)
> >
> > So this API should be called by platform driver only in case of synchronization
> > support, right?
> > In this case i would rename it as there is also a state machine in "normal" boot
> > proposal: rproc_set_sync_machine or rproc_set_sync_state_machine
> >
>
> Reviewing the stm32 series, i wonder if sync_flags should be a pointer to a const structure
> as the platform driver should not update it during the rproc live cycle.
> Then IMO, using a pointer to the structure instead of the structure seems more
> in line with the rest of the remoteproc API.

Humm... If we do make sync_flags constant then the platform drivers can't modify
the values dynamically, as I did in the stm32 series. This is something Loic
had asked for.

Moreover function rproc_set_state_machine() can't be called twice so updating
the sync_flags can't happen.

>
> >> +{
> >> + if (!rproc || !sync_ops)
> >> + return -EINVAL;
> >> +
> >> + /*
> >> + * No point in going further if we never have to synchronise with
> >> + * the remote processor.
> >> + */
> >> + if (!sync_flags.on_init &&
> >> + !sync_flags.after_stop && !sync_flags.after_crash)
> >> + return 0;
> >> +
> >> + /*
> >> + * Refuse to go further if remoteproc operations have been allocated
> >> + * but they will never be used.
> >> + */
> >> + if (rproc->ops && sync_flags.on_init &&
> >> + sync_flags.after_stop && sync_flags.after_crash)
> >> + return -EINVAL;
> >> +
> >> + /*
> >> + * Don't allow users to set this more than once to avoid situations
> >> + * where the remote processor can't be recovered.
> >> + */
> >> + if (rproc->sync_ops)
> >> + return -EINVAL;
> >> +
> >> + rproc->sync_ops = kmemdup(sync_ops, sizeof(*sync_ops), GFP_KERNEL);
> >> + if (!rproc->sync_ops)
> >> + return -ENOMEM;
> >> +
> >> + rproc->sync_flags = sync_flags;
> >> + /* Tell the core what to do when initialising */
> >> + rproc_set_sync_flag(rproc, RPROC_SYNC_STATE_INIT);
> >
> > Is there a use case where sync_flags.on_init is false and other flags are true?
> >
> > Look like on_init is useless and should not be exposed to the platform driver.
> > Or comments are missing to explain the usage of it vs the other flags.
> >
> > Regards,
> > Arnaud
> >
> >> +
> >> + return 0;
> >> +}
> >> +EXPORT_SYMBOL(rproc_set_state_machine);
> >> +
> >> /**
> >> * rproc_type_release() - release a remote processor instance
> >> * @dev: the rproc's device
> >> @@ -2088,6 +2141,7 @@ static void rproc_type_release(struct device *dev)
> >> kfree_const(rproc->firmware);
> >> kfree_const(rproc->name);
> >> kfree(rproc->ops);
> >> + kfree(rproc->sync_ops);
> >> kfree(rproc);
> >> }
> >>
> >> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> >> index 7dcc0a26892b..c1a293a37c78 100644
> >> --- a/drivers/remoteproc/remoteproc_internal.h
> >> +++ b/drivers/remoteproc/remoteproc_internal.h
> >> @@ -27,6 +27,8 @@ struct rproc_debug_trace {
> >> /*
> >> * enum rproc_sync_states - remote processsor sync states
> >> *
> >> + * @RPROC_SYNC_STATE_INIT state to use when the remoteproc core
> >> + * is initialising.
> >> * @RPROC_SYNC_STATE_SHUTDOWN state to use after the remoteproc core
> >> * has shutdown (rproc_shutdown()) the
> >> * remote processor.
> >> @@ -39,6 +41,7 @@ struct rproc_debug_trace {
> >> * operation to use.
> >> */
> >> enum rproc_sync_states {
> >> + RPROC_SYNC_STATE_INIT,
> >> RPROC_SYNC_STATE_SHUTDOWN,
> >> RPROC_SYNC_STATE_CRASHED,
> >> };
> >> @@ -47,6 +50,9 @@ static inline void rproc_set_sync_flag(struct rproc *rproc,
> >> enum rproc_sync_states state)
> >> {
> >> switch (state) {
> >> + case RPROC_SYNC_STATE_INIT:
> >> + rproc->sync_with_rproc = rproc->sync_flags.on_init;
> >> + break;
> >> case RPROC_SYNC_STATE_SHUTDOWN:
> >> rproc->sync_with_rproc = rproc->sync_flags.after_stop;
> >> break;
> >> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> >> index ceb3b2bba824..a75ed92b3de6 100644
> >> --- a/include/linux/remoteproc.h
> >> +++ b/include/linux/remoteproc.h
> >> @@ -619,6 +619,9 @@ struct rproc *rproc_get_by_child(struct device *dev);
> >> struct rproc *rproc_alloc(struct device *dev, const char *name,
> >> const struct rproc_ops *ops,
> >> const char *firmware, int len);
> >> +int rproc_set_state_machine(struct rproc *rproc,
> >> + const struct rproc_ops *sync_ops,
> >> + struct rproc_sync_flags sync_flags);
> >> void rproc_put(struct rproc *rproc);
> >> int rproc_add(struct rproc *rproc);
> >> int rproc_del(struct rproc *rproc);
> >>