drm/amd/powerplay: simplify the code around setting power limit

Use the cached max/current power limit and move the input check
to the top layer.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/amdgpu_smu.c

@@ -2239,9 +2239,20 @@ int smu_set_power_limit(struct smu_context *smu, uint32_t limit)
 
 	mutex_lock(&smu->mutex);
 
+	if (limit > smu->max_power_limit) {
+		dev_err(smu->adev->dev,
+			"New power limit (%d) is over the max allowed %d\n",
+			limit, smu->max_power_limit);
+		goto out;
+	}
+
+	if (!limit)
+		limit = smu->current_power_limit;
+
 	if (smu->ppt_funcs->set_power_limit)
 		ret = smu->ppt_funcs->set_power_limit(smu, limit);
 
+out:
 	mutex_unlock(&smu->mutex);
 
 	return ret;

drivers/gpu/drm/amd/powerplay/smu_v11_0.c

@@ -1082,19 +1082,6 @@ int smu_v11_0_get_current_power_limit(struct smu_context *smu,
 int smu_v11_0_set_power_limit(struct smu_context *smu, uint32_t n)
 {
 	int ret = 0;
-	uint32_t max_power_limit;
-
-	max_power_limit = smu_get_max_power_limit(smu);
-
-	if (n > max_power_limit) {
-		dev_err(smu->adev->dev, "New power limit (%d) is over the max allowed %d\n",
-				n,
-				max_power_limit);
-		return -EINVAL;
-	}
-
-	if (n == 0)
-		n = smu->default_power_limit;
 
 	if (!smu_feature_is_enabled(smu, SMU_FEATURE_PPT_BIT)) {
 		dev_err(smu->adev->dev, "Setting new power limit is not supported!\n");
@@ -1106,7 +1093,8 @@ int smu_v11_0_set_power_limit(struct smu_context *smu, uint32_t n)
 		dev_err(smu->adev->dev, "[%s] Set power limit Failed!\n", __func__);
 		return ret;
 	}
-	smu->power_limit = n;
+
+	smu->current_power_limit = n;
 
 	return 0;
 }