firmware: arm_scmi: Check beforehand if the perf domain set operations are allowed

Certain SCMI performance domains may have restrictions on the set level
and/or limits operation. If the set level/limits are performed by an
agent who is not allowed to do so may get SCMI_ERR_SUPPORT. However,
since this information about the domain is already known to the
agent(OSPM here) obtained via PERF_DOMAIN_ATTRIBUTES, the agent(OSPM)
can avoid making PERF_LEVEL_SET and PERF_LIMITS_SET calls to the firmware.

Add those checks and return -ENOTSUPP to the caller without interacting
with the firmware based on the information collected during the domain
enumeration stage.

Signed-off-by: xinglong.yang <xinglong.yang@cixtech.com>
Link: https://lore.kernel.org/r/20231109082855.472681-1-xinglong.yang@cixtech.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

Author: xinglong.yang

drivers/firmware/arm_scmi/perf.c

@@ -504,6 +504,9 @@ static int scmi_perf_limits_set(const struct scmi_protocol_handle *ph,
 	if (IS_ERR(dom))
 		return PTR_ERR(dom);
 
+	if (!dom->set_limits)
+		return -EOPNOTSUPP;
+
 	if (PROTOCOL_REV_MAJOR(pi->version) >= 0x3 && !max_perf && !min_perf)
 		return -EINVAL;
 
@@ -654,6 +657,9 @@ static int scmi_perf_level_set(const struct scmi_protocol_handle *ph,
 	if (IS_ERR(dom))
 		return PTR_ERR(dom);
 
+	if (!dom->info.set_perf)
+		return -EOPNOTSUPP;
+
 	if (dom->level_indexing_mode) {
 		struct scmi_opp *opp;