firmware: arm_scmi: Implement is_notify_supported callback in powercap protocol

Add a preliminary check to verify if the powercap protocol related notify
enable commands are supported at all by the SCMI platform, and then
provide the callback needed to allow the core SCMI notification
subsytem to do a fine-grain check if a specific resource domain
supports notifications.
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20240212123233.1230090-10-cristian.marussi@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/powercap.c

@@ -124,6 +124,8 @@ struct scmi_powercap_state {
 struct powercap_info {
 	u32 version;
 	int num_domains;
+	bool notify_cap_cmd;
+	bool notify_measurements_cmd;
 	struct scmi_powercap_state *states;
 	struct scmi_powercap_info *powercaps;
 };
@@ -157,6 +159,18 @@ scmi_powercap_attributes_get(const struct scmi_protocol_handle *ph,
 	}
 
 	ph->xops->xfer_put(ph, t);
+
+	if (!ret) {
+		if (!ph->hops->protocol_msg_check(ph,
+						  POWERCAP_CAP_NOTIFY, NULL))
+			pi->notify_cap_cmd = true;
+
+		if (!ph->hops->protocol_msg_check(ph,
+						  POWERCAP_MEASUREMENTS_NOTIFY,
+						  NULL))
+			pi->notify_measurements_cmd = true;
+	}
+
 	return ret;
 }
 
@@ -200,10 +214,12 @@ scmi_powercap_domain_attributes_get(const struct scmi_protocol_handle *ph,
 		flags = le32_to_cpu(resp->attributes);
 
 		dom_info->id = domain;
-		dom_info->notify_powercap_cap_change =
-			SUPPORTS_POWERCAP_CAP_CHANGE_NOTIFY(flags);
-		dom_info->notify_powercap_measurement_change =
-			SUPPORTS_POWERCAP_MEASUREMENTS_CHANGE_NOTIFY(flags);
+		if (pinfo->notify_cap_cmd)
+			dom_info->notify_powercap_cap_change =
+				SUPPORTS_POWERCAP_CAP_CHANGE_NOTIFY(flags);
+		if (pinfo->notify_measurements_cmd)
+			dom_info->notify_powercap_measurement_change =
+				SUPPORTS_POWERCAP_MEASUREMENTS_CHANGE_NOTIFY(flags);
 		dom_info->async_powercap_cap_set =
 			SUPPORTS_ASYNC_POWERCAP_CAP_SET(flags);
 		dom_info->powercap_cap_config =
@@ -788,6 +804,26 @@ static int scmi_powercap_notify(const struct scmi_protocol_handle *ph,
 	return ret;
 }
 
+static bool
+scmi_powercap_notify_supported(const struct scmi_protocol_handle *ph,
+			       u8 evt_id, u32 src_id)
+{
+	bool supported = false;
+	const struct scmi_powercap_info *dom_info;
+	struct powercap_info *pi = ph->get_priv(ph);
+
+	if (evt_id >= ARRAY_SIZE(evt_2_cmd) || src_id >= pi->num_domains)
+		return false;
+
+	dom_info = pi->powercaps + src_id;
+	if (evt_id == SCMI_EVENT_POWERCAP_CAP_CHANGED)
+		supported = dom_info->notify_powercap_cap_change;
+	else if (evt_id == SCMI_EVENT_POWERCAP_MEASUREMENTS_CHANGED)
+		supported = dom_info->notify_powercap_measurement_change;
+
+	return supported;
+}
+
 static int
 scmi_powercap_set_notify_enabled(const struct scmi_protocol_handle *ph,
 				 u8 evt_id, u32 src_id, bool enable)
@@ -904,6 +940,7 @@ static const struct scmi_event powercap_events[] = {
 };
 
 static const struct scmi_event_ops powercap_event_ops = {
+	.is_notify_supported = scmi_powercap_notify_supported,
 	.get_num_sources = scmi_powercap_get_num_sources,
 	.set_notify_enabled = scmi_powercap_set_notify_enabled,
 	.fill_custom_report = scmi_powercap_fill_custom_report,