diff --git a/drivers/renesas/rzg/ddr/boot_init_dram.h b/drivers/renesas/rzg/ddr/boot_init_dram.h
new file mode 100644
index 0000000..294582f
--- /dev/null
+++ b/drivers/renesas/rzg/ddr/boot_init_dram.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2020, Renesas Electronics Corporation. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef BOOT_INIT_DRAM_H
+#define BOOT_INIT_DRAM_H
+
+extern int32_t rzg_dram_init(void);
+
+#define INITDRAM_OK		0
+#define INITDRAM_NG		0xffffffff
+#define INITDRAM_ERR_I		0xffffffff
+#define INITDRAM_ERR_O		0xfffffffe
+#define INITDRAM_ERR_T		0xfffffff0
+
+#endif /* BOOT_INIT_DRAM_H */