drm/amd/powerplay: implement sysfs of get num states function

add function smu_get_power_num_state function for sw-smu.
it's only for sysfs interface, the power state feature is not ready for sw-smu.
Signed-off-by: Kevin Wang <Kevin1.Wang@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -350,9 +350,13 @@ static ssize_t amdgpu_get_pp_num_states(struct device *dev,
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct amdgpu_device *adev = ddev->dev_private;
 	struct pp_states_info data;
-	int i, buf_len;
+	int i, buf_len, ret;
 
-	if (adev->powerplay.pp_funcs->get_pp_num_states)
+	if (is_support_sw_smu(adev)) {
+		ret = smu_get_power_num_states(&adev->smu, &data);
+		if (ret)
+			return ret;
+	} else if (adev->powerplay.pp_funcs->get_pp_num_states)
 		amdgpu_dpm_get_pp_num_states(adev, &data);
 
 	buf_len = snprintf(buf, PAGE_SIZE, "states: %d\n", data.nums);

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

@@ -29,6 +29,19 @@
 #include "smu_v11_0.h"
 #include "atom.h"
 
+int smu_get_power_num_states(struct smu_context *smu,
+			     struct pp_states_info *state_info)
+{
+	if (!state_info)
+		return -EINVAL;
+
+	/* not support power state */
+	memset(state_info, 0, sizeof(struct pp_states_info));
+	state_info->nums = 0;
+
+	return 0;
+}
+
 int smu_common_read_sensor(struct smu_context *smu, enum amd_pp_sensors sensor,
 			   void *data, uint32_t *size)
 {

drivers/gpu/drm/amd/powerplay/inc/amdgpu_smu.h

@@ -381,5 +381,6 @@ int smu_common_read_sensor(struct smu_context *smu, enum amd_pp_sensors sensor,
 			   void *data, uint32_t *size);
 int smu_sys_get_pp_table(struct smu_context *smu, void **table);
 int smu_sys_set_pp_table(struct smu_context *smu,  void *buf, size_t size);
+int smu_get_power_num_states(struct smu_context *smu, struct pp_states_info *state_info);
 
 #endif