[PATCH v4 04/31] firmware: arm_scmi: Allow protocols to register for notifications

Allow protocols themselves to register for their own notifications and
provide their own notifier callbacks.

Signed-off-by: Cristian Marussi <[email protected]>
---
v2-->v3
 - split out unrelated changes on event sizing
v1-->v2
 - Fixed multiline comment format
---
 drivers/firmware/arm_scmi/common.h    |  4 ++++
 drivers/firmware/arm_scmi/driver.c    | 12 ++++++++++++
 drivers/firmware/arm_scmi/notify.c    |  6 +++---
 drivers/firmware/arm_scmi/protocols.h |  6 ++++++
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
index abe2fa3d41dd..a8a45bacfa3f 100644
--- a/drivers/firmware/arm_scmi/common.h
+++ b/drivers/firmware/arm_scmi/common.h
@@ -17,6 +17,7 @@
 #include <linux/hashtable.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/notifier.h>
 #include <linux/refcount.h>
 #include <linux/scmi_protocol.h>
 #include <linux/spinlock.h>
@@ -533,5 +534,8 @@ static struct platform_driver __drv = {					       \
 void scmi_notification_instance_data_set(const struct scmi_handle *handle,
 					 void *priv);
 void *scmi_notification_instance_data_get(const struct scmi_handle *handle);
+int scmi_notifier_register(const struct scmi_handle *handle, u8 proto_id,
+			   u8 evt_id, const u32 *src_id,
+			   struct notifier_block *nb);
 int scmi_inflight_count(const struct scmi_handle *handle);
 #endif /* _SCMI_COMMON_H */
diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 2ee4cad1f93d..9c1ab9925b1d 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -1655,6 +1655,17 @@ static void *scmi_get_protocol_priv(const struct scmi_protocol_handle *ph)
 	return pi->priv;
 }
 
+static int
+scmi_register_instance_notifier(const struct scmi_protocol_handle *ph,
+				u8 evt_id, const u32 *src_id,
+				struct notifier_block *nb)
+{
+	const struct scmi_protocol_instance *pi = ph_to_pi(ph);
+
+	return scmi_notifier_register(pi->handle, pi->proto->id,
+				      evt_id, src_id, nb);
+}
+
 static const struct scmi_xfer_ops xfer_ops = {
 	.xfer_get_init = xfer_get_init,
 	.reset_rx_to_maxsz = reset_rx_to_maxsz,
@@ -2223,6 +2234,7 @@ scmi_alloc_init_protocol_instance(struct scmi_info *info,
 	pi->ph.hops = &helpers_ops;
 	pi->ph.set_priv = scmi_set_protocol_priv;
 	pi->ph.get_priv = scmi_get_protocol_priv;
+	pi->ph.notifier_register = scmi_register_instance_notifier;
 	refcount_set(&pi->users, 1);
 
 	/*
diff --git a/drivers/firmware/arm_scmi/notify.c b/drivers/firmware/arm_scmi/notify.c
index 3e4c97ab7b61..2a8efdf0bab8 100644
--- a/drivers/firmware/arm_scmi/notify.c
+++ b/drivers/firmware/arm_scmi/notify.c
@@ -1389,9 +1389,9 @@ static int scmi_event_handler_enable_events(struct scmi_event_handler *hndl)
  *
  * Return: 0 on Success
  */
-static int scmi_notifier_register(const struct scmi_handle *handle,
-				  u8 proto_id, u8 evt_id, const u32 *src_id,
-				  struct notifier_block *nb)
+int scmi_notifier_register(const struct scmi_handle *handle,
+			   u8 proto_id, u8 evt_id, const u32 *src_id,
+			   struct notifier_block *nb)
 {
 	int ret = 0;
 	u32 evt_key;
diff --git a/drivers/firmware/arm_scmi/protocols.h b/drivers/firmware/arm_scmi/protocols.h
index f51245aca259..3e7b6f8aa72c 100644
--- a/drivers/firmware/arm_scmi/protocols.h
+++ b/drivers/firmware/arm_scmi/protocols.h
@@ -166,6 +166,9 @@ struct scmi_proto_helpers_ops;
  *	  can be used by the protocol implementation to generate SCMI messages.
  * @set_priv: A method to set protocol private data for this instance.
  * @get_priv: A method to get protocol private data previously set.
+ * @notifier_register: A method to register interest for notifications from
+ *		       within a protocol implementation unit: notifiers can
+ *		       be registered only for the same protocol.
  *
  * This structure represents a protocol initialized against specific SCMI
  * instance and it will be used as follows:
@@ -185,6 +188,9 @@ struct scmi_protocol_handle {
 	const struct scmi_proto_helpers_ops *hops;
 	int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
 	void *(*get_priv)(const struct scmi_protocol_handle *ph);
+	int (*notifier_register)(const struct scmi_protocol_handle *ph,
+				 u8 evt_id, const u32 *src_id,
+				 struct notifier_block *nb);
 };
 
 /**
-- 
2.54.0