diff --git a/drivers/renesas/rzg/ddr/dram_sub_func.h b/drivers/renesas/rzg/ddr/dram_sub_func.h
new file mode 100644
index 0000000..7affb61
--- /dev/null
+++ b/drivers/renesas/rzg/ddr/dram_sub_func.h
@@ -0,0 +1,14 @@
+/*
+ * Copyright (c) 2020, Renesas Electronics Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef DRAM_SUB_FUNC_H
+#define DRAM_SUB_FUNC_H
+
+#define DRAM_UPDATE_STATUS_ERR	-1
+#define DRAM_BOOT_STATUS_COLD	0
+#define DRAM_BOOT_STATUS_WARM	1
+
+#endif /* DRAM_SUB_FUNC_H */