drm/amd/pp: Implement load_firmware interface

with this interface, gfx/sdma can be initialized
before smu.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -270,8 +270,23 @@ const struct amdgpu_ip_block_version pp_smu_ip_block =
 	.funcs = &pp_ip_funcs,
 };
 
+/* This interface only be supported On Vi,
+ * because only smu7/8 can help to load gfx/sdma fw,
+ * smu need to be enabled before load other ip's fw.
+ * so call start smu to load smu7 fw and other ip's fw
+ */
 static int pp_dpm_load_fw(void *handle)
 {
+	struct pp_hwmgr *hwmgr = handle;
+
+	if (!hwmgr || !hwmgr->smumgr_funcs || !hwmgr->smumgr_funcs->start_smu)
+		return -EINVAL;
+
+	if (hwmgr->smumgr_funcs->start_smu(hwmgr)) {
+		pr_err("fw load failed\n");
+		return -EINVAL;
+	}
+
 	return 0;
 }