[PATCH v2] firmware: arm_scmi: Refrain set operations of perf

[xinglong.yang]

Refrain from trying to take the SET operation where the set_* operations
are not supported, because: (1.) avoid unneeded SCMI exchanges, (2.)
avoids to trust the FW reply blindly.

Signed-off-by: xinglong.yang <xinglong.yang at cixtech.com>
---
 drivers/firmware/arm_scmi/perf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 431bda9165c3..3bcdef91ed5c 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -377,6 +377,9 @@ 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;
 
@@ -473,6 +476,9 @@ static int scmi_perf_level_set(const struct scmi_protocol_handle *ph,
 	if (IS_ERR(dom))
 		return PTR_ERR(dom);
 
+	if (!dom->set_perf)
+		return -EOPNOTSUPP;
+
 	if (dom->fc_info && dom->fc_info[PERF_FC_LEVEL].set_addr) {
 		struct scmi_fc_info *fci = &dom->fc_info[PERF_FC_LEVEL];
 
-- 
2.42.0