diff --git a/include/s3c6400.h b/include/s3c6400.h
index fd3e99b..d3f136d 100644
--- a/include/s3c6400.h
+++ b/include/s3c6400.h
@@ -380,6 +380,11 @@
  */
 #define ELFIN_MEM_SYS_CFG	0x7e00f120
 
+#define S3C64XX_MEM_SYS_CFG_16BIT	(1 << 12)
+
+#define S3C64XX_MEM_SYS_CFG_NAND	0x0008
+#define S3C64XX_MEM_SYS_CFG_ONENAND	S3C64XX_MEM_SYS_CFG_16BIT
+
 #define GPACON		(ELFIN_GPIO_BASE + GPACON_OFFSET)
 #define GPADAT		(ELFIN_GPIO_BASE + GPADAT_OFFSET)
 #define GPAPUD		(ELFIN_GPIO_BASE + GPAPUD_OFFSET)