On 4/30/20 10:51 PM, Mathieu Poirier wrote:

On Wed, Apr 29, 2020 at 04:38:54PM +0200, Arnaud POULIQUEN wrote:

quoted

On 4/29/20 11:22 AM, Arnaud POULIQUEN wrote:

quoted

On 4/24/20 10:01 PM, Mathieu Poirier wrote:

quoted

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.

You are right, make it constant is not a good idea.

Regards,
Arnaud 

quoted

quoted

quoted

+{
+	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
 

quoted

+
+	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);