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

Arnaud POULIQUEN
2020-04-29T14:39:06Z

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.

>> +{
>> + 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);
>>