diff --git a/drivers/mtd/mtd_uboot.c b/drivers/mtd/mtd_uboot.c
index 7197007..c517b9c 100644
--- a/drivers/mtd/mtd_uboot.c
+++ b/drivers/mtd/mtd_uboot.c
@@ -43,7 +43,7 @@ static int get_part(const char *partname, int *idx, loff_t *off, loff_t *size,
 }
 
 int mtd_arg_off(const char *arg, int *idx, loff_t *off, loff_t *size,
-		loff_t *maxsize, int devtype, int chipsize)
+		loff_t *maxsize, int devtype, uint64_t chipsize)
 {
 	if (!str2off(arg, off))
 		return get_part(arg, idx, off, size, maxsize, devtype);
@@ -59,7 +59,8 @@ int mtd_arg_off(const char *arg, int *idx, loff_t *off, loff_t *size,
 }
 
 int mtd_arg_off_size(int argc, char *const argv[], int *idx, loff_t *off,
-		 loff_t *size, loff_t *maxsize, int devtype, int chipsize)
+		     loff_t *size, loff_t *maxsize, int devtype,
+		     uint64_t chipsize)
 {
 	int ret;
 
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 33669da..552d4d6 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -484,8 +484,9 @@ int add_mtd_partitions(struct mtd_info *, const struct mtd_partition *, int);
 int del_mtd_partitions(struct mtd_info *);
 
 int mtd_arg_off(const char *arg, int *idx, loff_t *off, loff_t *size,
-		loff_t *maxsize, int devtype, int chipsize);
+		loff_t *maxsize, int devtype, uint64_t chipsize);
 int mtd_arg_off_size(int argc, char *const argv[], int *idx, loff_t *off,
-		 loff_t *size, loff_t *maxsize, int devtype, int chipsize);
+		     loff_t *size, loff_t *maxsize, int devtype,
+		     uint64_t chipsize);
 #endif
 #endif /* __MTD_MTD_H__ */