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

[Arnaud POULIQUEN <arnaud.pouliquen@st.com>]

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

> +{
> +	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);
>