firmware: arm_scmi: Implement is_notify_supported callback in perf protocol

Add a preliminary check to verify if the performance 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/20240212123233.1230090-4-cristian.marussi@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_scmi/perf.c

@@ -182,6 +182,8 @@ struct scmi_perf_info {
 	enum scmi_power_scale power_scale;
 	u64 stats_addr;
 	u32 stats_size;
+	bool notify_lvl_cmd;
+	bool notify_lim_cmd;
 	struct perf_dom_info *dom_info;
 };
 
@@ -222,6 +224,15 @@ static int scmi_perf_attributes_get(const struct scmi_protocol_handle *ph,
 	}
 
 	ph->xops->xfer_put(ph, t);
+
+	if (!ret) {
+		if (!ph->hops->protocol_msg_check(ph, PERF_NOTIFY_LEVEL, NULL))
+			pi->notify_lvl_cmd = true;
+
+		if (!ph->hops->protocol_msg_check(ph, PERF_NOTIFY_LIMITS, NULL))
+			pi->notify_lim_cmd = true;
+	}
+
 	return ret;
 }
 
@@ -239,6 +250,7 @@ static void scmi_perf_xa_destroy(void *data)
 static int
 scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph,
 				struct perf_dom_info *dom_info,
+				bool notify_lim_cmd, bool notify_lvl_cmd,
 				u32 version)
 {
 	int ret;
@@ -260,8 +272,12 @@ scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph,
 
 		dom_info->set_limits = SUPPORTS_SET_LIMITS(flags);
 		dom_info->info.set_perf = SUPPORTS_SET_PERF_LVL(flags);
-		dom_info->perf_limit_notify = SUPPORTS_PERF_LIMIT_NOTIFY(flags);
-		dom_info->perf_level_notify = SUPPORTS_PERF_LEVEL_NOTIFY(flags);
+		if (notify_lim_cmd)
+			dom_info->perf_limit_notify =
+				SUPPORTS_PERF_LIMIT_NOTIFY(flags);
+		if (notify_lvl_cmd)
+			dom_info->perf_level_notify =
+				SUPPORTS_PERF_LEVEL_NOTIFY(flags);
 		dom_info->perf_fastchannels = SUPPORTS_PERF_FASTCHANNELS(flags);
 		if (PROTOCOL_REV_MAJOR(version) >= 0x4)
 			dom_info->level_indexing_mode =
@@ -993,6 +1009,27 @@ static const struct scmi_perf_proto_ops perf_proto_ops = {
 	.power_scale_get = scmi_power_scale_get,
 };
 
+static bool scmi_perf_notify_supported(const struct scmi_protocol_handle *ph,
+				       u8 evt_id, u32 src_id)
+{
+	bool supported;
+	struct perf_dom_info *dom;
+
+	if (evt_id >= ARRAY_SIZE(evt_2_cmd))
+		return false;
+
+	dom = scmi_perf_domain_lookup(ph, src_id);
+	if (IS_ERR(dom))
+		return false;
+
+	if (evt_id == SCMI_EVENT_PERFORMANCE_LIMITS_CHANGED)
+		supported = dom->perf_limit_notify;
+	else
+		supported = dom->perf_level_notify;
+
+	return supported;
+}
+
 static int scmi_perf_set_notify_enabled(const struct scmi_protocol_handle *ph,
 					u8 evt_id, u32 src_id, bool enable)
 {
@@ -1082,6 +1119,7 @@ static const struct scmi_event perf_events[] = {
 };
 
 static const struct scmi_event_ops perf_event_ops = {
+	.is_notify_supported = scmi_perf_notify_supported,
 	.get_num_sources = scmi_perf_get_num_sources,
 	.set_notify_enabled = scmi_perf_set_notify_enabled,
 	.fill_custom_report = scmi_perf_fill_custom_report,
@@ -1126,7 +1164,8 @@ static int scmi_perf_protocol_init(const struct scmi_protocol_handle *ph)
 		struct perf_dom_info *dom = pinfo->dom_info + domain;
 
 		dom->id = domain;
-		scmi_perf_domain_attributes_get(ph, dom, version);
+		scmi_perf_domain_attributes_get(ph, dom, pinfo->notify_lim_cmd,
+						pinfo->notify_lvl_cmd, version);
 		scmi_perf_describe_levels_get(ph, dom, version);
 
 		if (dom->perf_fastchannels)