drm/amdgpu: add dpm helper function for DF Cstate control

The helper function hides software smu and legacy powerplay
implementation for DF Cstate control.
Signed-off-by: Hawking Zhang <Hawking.Zhang@amd.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1171,3 +1171,20 @@ int amdgpu_dpm_set_xgmi_pstate(struct amdgpu_device *adev,
 
 	return ret;
 }
+
+int amdgpu_dpm_set_df_cstate(struct amdgpu_device *adev,
+			     uint32_t cstate)
+{
+	int ret = 0;
+	const struct amd_pm_funcs *pp_funcs = adev->powerplay.pp_funcs;
+	void *pp_handle = adev->powerplay.pp_handle;
+	struct smu_context *smu = &adev->smu;
+
+	if (is_support_sw_smu(adev))
+		ret = smu_set_df_cstate(smu, cstate);
+	else if (pp_funcs &&
+		 pp_funcs->set_df_cstate)
+		ret = pp_funcs->set_df_cstate(pp_handle, cstate);
+
+	return ret;
+}

drivers/gpu/drm/amd/amdgpu/amdgpu_dpm.h

@@ -533,4 +533,7 @@ int amdgpu_dpm_baco_exit(struct amdgpu_device *adev);
 
 int amdgpu_dpm_baco_enter(struct amdgpu_device *adev);
 
+int amdgpu_dpm_set_df_cstate(struct amdgpu_device *adev,
+			     uint32_t cstate);
+
 #endif