drm/amd/pm: add xgmi_plpd_policy sysfs node for user to change plpd policy

Add xgmi_plpd_policy sysfs node for users to check and select xgmi
per-link power down policy:
  - arg 0: disallow plpd
  - arg 1: default policy
  - arg 2: optimized policy

v2: split from smu v13.0.6 code and miscellaneous updates
v3: add usage comments around set/get functions
Signed-off-by: Le Ma <le.ma@amd.com>
Reviewed-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/amdgpu_dpm.c

@@ -365,6 +365,49 @@ int amdgpu_dpm_allow_xgmi_power_down(struct amdgpu_device *adev, bool en)
 	return ret;
 }
 
+int amdgpu_dpm_get_xgmi_plpd_mode(struct amdgpu_device *adev, char **mode_desc)
+{
+	struct smu_context *smu = adev->powerplay.pp_handle;
+	int mode = XGMI_PLPD_NONE;
+
+	if (is_support_sw_smu(adev)) {
+		mode = smu->plpd_mode;
+		if (mode_desc == NULL)
+			return mode;
+		switch (smu->plpd_mode) {
+		case XGMI_PLPD_DISALLOW:
+			*mode_desc = "disallow";
+			break;
+		case XGMI_PLPD_DEFAULT:
+			*mode_desc = "default";
+			break;
+		case XGMI_PLPD_OPTIMIZED:
+			*mode_desc = "optimized";
+			break;
+		case XGMI_PLPD_NONE:
+		default:
+			*mode_desc = "none";
+			break;
+		}
+	}
+
+	return mode;
+}
+
+int amdgpu_dpm_set_xgmi_plpd_mode(struct amdgpu_device *adev, int mode)
+{
+	struct smu_context *smu = adev->powerplay.pp_handle;
+	int ret = -EOPNOTSUPP;
+
+	if (is_support_sw_smu(adev)) {
+		mutex_lock(&adev->pm.mutex);
+		ret = smu_set_xgmi_plpd_mode(smu, mode);
+		mutex_unlock(&adev->pm.mutex);
+	}
+
+	return ret;
+}
+
 int amdgpu_dpm_enable_mgpu_fan_boost(struct amdgpu_device *adev)
 {
 	void *pp_handle = adev->powerplay.pp_handle;

drivers/gpu/drm/amd/pm/amdgpu_pm.c

@@ -1991,6 +1991,70 @@ static int ss_bias_attr_update(struct amdgpu_device *adev, struct amdgpu_device_
 	return 0;
 }
 
+/* Following items will be read out to indicate current plpd policy:
+ *  - -1: none
+ *  - 0: disallow
+ *  - 1: default
+ *  - 2: optimized
+ */
+static ssize_t amdgpu_get_xgmi_plpd_policy(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	char *mode_desc = "none";
+	int mode;
+
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+	if (adev->in_suspend && !adev->in_runpm)
+		return -EPERM;
+
+	mode = amdgpu_dpm_get_xgmi_plpd_mode(adev, &mode_desc);
+
+	return sysfs_emit(buf, "%d: %s\n", mode, mode_desc);
+}
+
+/* Following argument value is expected from user to change plpd policy
+ *  - arg 0: disallow plpd
+ *  - arg 1: default policy
+ *  - arg 2: optimized policy
+ */
+static ssize_t amdgpu_set_xgmi_plpd_policy(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	int mode, ret;
+
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+	if (adev->in_suspend && !adev->in_runpm)
+		return -EPERM;
+
+	ret = kstrtos32(buf, 0, &mode);
+	if (ret)
+		return -EINVAL;
+
+	ret = pm_runtime_get_sync(ddev->dev);
+	if (ret < 0) {
+		pm_runtime_put_autosuspend(ddev->dev);
+		return ret;
+	}
+
+	ret = amdgpu_dpm_set_xgmi_plpd_mode(adev, mode);
+
+	pm_runtime_mark_last_busy(ddev->dev);
+	pm_runtime_put_autosuspend(ddev->dev);
+
+	if (ret)
+		return ret;
+
+	return count;
+}
+
 static struct amdgpu_device_attr amdgpu_device_attrs[] = {
 	AMDGPU_DEVICE_ATTR_RW(power_dpm_state,				ATTR_FLAG_BASIC|ATTR_FLAG_ONEVF),
 	AMDGPU_DEVICE_ATTR_RW(power_dpm_force_performance_level,	ATTR_FLAG_BASIC|ATTR_FLAG_ONEVF),
@@ -2026,6 +2090,7 @@ static struct amdgpu_device_attr amdgpu_device_attrs[] = {
 			      .attr_update = ss_power_attr_update),
 	AMDGPU_DEVICE_ATTR_RW(smartshift_bias,				ATTR_FLAG_BASIC,
 			      .attr_update = ss_bias_attr_update),
+	AMDGPU_DEVICE_ATTR_RW(xgmi_plpd_policy,				ATTR_FLAG_BASIC),
 };
 
 static int default_attr_update(struct amdgpu_device *adev, struct amdgpu_device_attr *attr,
@@ -2124,6 +2189,9 @@ static int default_attr_update(struct amdgpu_device *adev, struct amdgpu_device_
 			*states = ATTR_STATE_UNSUPPORTED;
 		else if (gc_ver == IP_VERSION(10, 3, 0) && amdgpu_sriov_vf(adev))
 			*states = ATTR_STATE_UNSUPPORTED;
+	} else if (DEVICE_ATTR_IS(xgmi_plpd_policy)) {
+		if (amdgpu_dpm_get_xgmi_plpd_mode(adev, NULL) == XGMI_PLPD_NONE)
+			*states = ATTR_STATE_UNSUPPORTED;
 	}
 
 	switch (gc_ver) {

drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h

@@ -426,6 +426,11 @@ int amdgpu_dpm_set_df_cstate(struct amdgpu_device *adev,
 
 int amdgpu_dpm_allow_xgmi_power_down(struct amdgpu_device *adev, bool en);
 
+int amdgpu_dpm_get_xgmi_plpd_mode(struct amdgpu_device *adev,
+				  char **mode);
+
+int amdgpu_dpm_set_xgmi_plpd_mode(struct amdgpu_device *adev, int mode);
+
 int amdgpu_dpm_enable_mgpu_fan_boost(struct amdgpu_device *adev);
 
 int amdgpu_dpm_set_clockgating_by_smu(struct amdgpu_device *adev,