diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
index 18154774f9..516dda6179 100644
--- a/drivers/dfu/dfu.c
+++ b/drivers/dfu/dfu.c
@@ -500,12 +500,29 @@ int dfu_read(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 static int dfu_fill_entity(struct dfu_entity *dfu, char *s, int alt,
 			   char *interface, char *devstr)
 {
+	char *argv[DFU_MAX_ENTITY_ARGS];
+	int argc;
 	char *st;
 
 	debug("%s: %s interface: %s dev: %s\n", __func__, s, interface, devstr);
 	st = strsep(&s, " \t");
 	strlcpy(dfu->name, st, DFU_NAME_SIZE);
-	s = skip_spaces(s);
+
+	/* Parse arguments */
+	for (argc = 0; s && argc < DFU_MAX_ENTITY_ARGS; argc++) {
+		s = skip_spaces(s);
+		if (!*s)
+			break;
+		argv[argc] = strsep(&s, " \t");
+	}
+
+	if (argc == DFU_MAX_ENTITY_ARGS && s) {
+		s = skip_spaces(s);
+		if (*s) {
+			log_err("Too many arguments for %s\n", dfu->name);
+			return -EINVAL;
+		}
+	}
 
 	dfu->alt = alt;
 	dfu->max_buf_size = 0;
@@ -513,22 +530,22 @@ static int dfu_fill_entity(struct dfu_entity *dfu, char *s, int alt,
 
 	/* Specific for mmc device */
 	if (strcmp(interface, "mmc") == 0) {
-		if (dfu_fill_entity_mmc(dfu, devstr, s))
+		if (dfu_fill_entity_mmc(dfu, devstr, argv, argc))
 			return -1;
 	} else if (strcmp(interface, "mtd") == 0) {
-		if (dfu_fill_entity_mtd(dfu, devstr, s))
+		if (dfu_fill_entity_mtd(dfu, devstr, argv, argc))
 			return -1;
 	} else if (strcmp(interface, "nand") == 0) {
-		if (dfu_fill_entity_nand(dfu, devstr, s))
+		if (dfu_fill_entity_nand(dfu, devstr, argv, argc))
 			return -1;
 	} else if (strcmp(interface, "ram") == 0) {
-		if (dfu_fill_entity_ram(dfu, devstr, s))
+		if (dfu_fill_entity_ram(dfu, devstr, argv, argc))
 			return -1;
 	} else if (strcmp(interface, "sf") == 0) {
-		if (dfu_fill_entity_sf(dfu, devstr, s))
+		if (dfu_fill_entity_sf(dfu, devstr, argv, argc))
 			return -1;
 	} else if (strcmp(interface, "virt") == 0) {
-		if (dfu_fill_entity_virt(dfu, devstr, s))
+		if (dfu_fill_entity_virt(dfu, devstr, argv, argc))
 			return -1;
 	} else {
 		printf("%s: Device %s not (yet) supported!\n",
diff --git a/drivers/dfu/dfu_mmc.c b/drivers/dfu/dfu_mmc.c
index d747ede66c..a91da972d4 100644
--- a/drivers/dfu/dfu_mmc.c
+++ b/drivers/dfu/dfu_mmc.c
@@ -337,35 +337,34 @@ void dfu_free_entity_mmc(struct dfu_entity *dfu)
  *	4th (optional):
  *		mmcpart <num> (access to HW eMMC partitions)
  */
-int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
 	const char *entity_type;
 	ssize_t second_arg;
 	size_t third_arg;
-
 	struct mmc *mmc;
+	char *s;
 
-	const char *argv[3];
-	const char **parg = argv;
-
-	dfu->data.mmc.dev_num = dectoul(devstr, NULL);
-
-	for (; parg < argv + sizeof(argv) / sizeof(*argv); ++parg) {
-		*parg = strsep(&s, " \t");
-		if (*parg == NULL) {
-			pr_err("Invalid number of arguments.\n");
-			return -ENODEV;
-		}
-		s = skip_spaces(s);
+	if (argc < 3) {
+		pr_err("The number of parameters are not enough.\n");
+		return -EINVAL;
 	}
 
+	dfu->data.mmc.dev_num = dectoul(devstr, &s);
+	if (*s)
+		return -EINVAL;
+
 	entity_type = argv[0];
 	/*
 	 * Base 0 means we'll accept (prefixed with 0x or 0) base 16, 8,
 	 * with default 10.
 	 */
-	second_arg = simple_strtol(argv[1], NULL, 0);
-	third_arg = simple_strtoul(argv[2], NULL, 0);
+	second_arg = simple_strtol(argv[1], &s, 0);
+	if (*s)
+		return -EINVAL;
+	third_arg = simple_strtoul(argv[2], &s, 0);
+	if (*s)
+		return -EINVAL;
 
 	mmc = find_mmc_device(dfu->data.mmc.dev_num);
 	if (mmc == NULL) {
@@ -390,12 +389,14 @@ int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s)
 		 * Check for an extra entry at dfu_alt_info env variable
 		 * specifying the mmc HW defined partition number
 		 */
-		if (s)
-			if (!strcmp(strsep(&s, " \t"), "mmcpart")) {
-				s = skip_spaces(s);
-				dfu->data.mmc.hw_partition =
-					simple_strtoul(s, NULL, 0);
+		if (argc > 3) {
+			if (argc != 5 || strcmp(argv[3], "mmcpart")) {
+				pr_err("DFU mmc raw accept 'mmcpart <partnum>' option.\n");
+				return -EINVAL;
 			}
+			dfu->data.mmc.hw_partition =
+				simple_strtoul(argv[4], NULL, 0);
+		}
 
 	} else if (!strcmp(entity_type, "part")) {
 		struct disk_partition partinfo;
@@ -414,15 +415,18 @@ int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s)
 		 * Check for an extra entry at dfu_alt_info env variable
 		 * specifying the mmc HW defined partition number
 		 */
-		if (s)
-			if (!strcmp(strsep(&s, " \t"), "offset")) {
-				s = skip_spaces(s);
-				offset = simple_strtoul(s, NULL, 0);
+		if (argc > 3) {
+			if (argc != 5 || strcmp(argv[3], "offset")) {
+				pr_err("DFU mmc raw accept 'mmcpart <partnum>' option.\n");
+				return -EINVAL;
 			}
+			dfu->data.mmc.hw_partition =
+				simple_strtoul(argv[4], NULL, 0);
+		}
 
 		dfu->layout			= DFU_RAW_ADDR;
 		dfu->data.mmc.lba_start		= partinfo.start + offset;
-		dfu->data.mmc.lba_size		= partinfo.size-offset;
+		dfu->data.mmc.lba_size		= partinfo.size - offset;
 		dfu->data.mmc.lba_blk_size	= partinfo.blksz;
 	} else if (!strcmp(entity_type, "fat")) {
 		dfu->layout = DFU_FS_FAT;
diff --git a/drivers/dfu/dfu_mtd.c b/drivers/dfu/dfu_mtd.c
index ee534a9d10..81357769ff 100644
--- a/drivers/dfu/dfu_mtd.c
+++ b/drivers/dfu/dfu_mtd.c
@@ -251,9 +251,9 @@ static unsigned int dfu_polltimeout_mtd(struct dfu_entity *dfu)
 	return DFU_DEFAULT_POLL_TIMEOUT;
 }
 
-int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
-	char *st;
+	char *s;
 	struct mtd_info *mtd;
 	int ret, part;
 
@@ -265,25 +265,33 @@ int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr, char *s)
 	dfu->dev_type = DFU_DEV_MTD;
 	dfu->data.mtd.info = mtd;
 	dfu->max_buf_size = mtd->erasesize;
+	if (argc < 1)
+		return -EINVAL;
 
-	st = strsep(&s, " \t");
-	s = skip_spaces(s);
-	if (!strcmp(st, "raw")) {
+	if (!strcmp(argv[0], "raw")) {
+		if (argc != 3)
+			return -EINVAL;
 		dfu->layout = DFU_RAW_ADDR;
-		dfu->data.mtd.start = hextoul(s, &s);
-		if (!isspace(*s))
-			return -1;
-		s = skip_spaces(s);
-		dfu->data.mtd.size = hextoul(s, &s);
-	} else if ((!strcmp(st, "part")) || (!strcmp(st, "partubi"))) {
+		dfu->data.mtd.start = hextoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
+		dfu->data.mtd.size = hextoul(argv[2], &s);
+		if (*s)
+			return -EINVAL;
+	} else if ((!strcmp(argv[0], "part")) || (!strcmp(argv[0], "partubi"))) {
 		char mtd_id[32];
 		struct mtd_device *mtd_dev;
 		u8 part_num;
 		struct part_info *pi;
 
+		if (argc != 2)
+			return -EINVAL;
+
 		dfu->layout = DFU_RAW_ADDR;
 
-		part = dectoul(s, &s);
+		part = dectoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
 
 		sprintf(mtd_id, "%s,%d", devstr, part - 1);
 		printf("using id '%s'\n", mtd_id);
@@ -298,10 +306,10 @@ int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr, char *s)
 
 		dfu->data.mtd.start = pi->offset;
 		dfu->data.mtd.size = pi->size;
-		if (!strcmp(st, "partubi"))
+		if (!strcmp(argv[0], "partubi"))
 			dfu->data.mtd.ubi = 1;
 	} else {
-		printf("%s: Memory layout (%s) not supported!\n", __func__, st);
+		printf("%s: Memory layout (%s) not supported!\n", __func__, argv[0]);
 		return -1;
 	}
 
diff --git a/drivers/dfu/dfu_nand.c b/drivers/dfu/dfu_nand.c
index 76761939ab..08e8cf5cdb 100644
--- a/drivers/dfu/dfu_nand.c
+++ b/drivers/dfu/dfu_nand.c
@@ -194,23 +194,25 @@ unsigned int dfu_polltimeout_nand(struct dfu_entity *dfu)
 	return DFU_DEFAULT_POLL_TIMEOUT;
 }
 
-int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
-	char *st;
+	char *s;
 	int ret, dev, part;
 
 	dfu->data.nand.ubi = 0;
 	dfu->dev_type = DFU_DEV_NAND;
-	st = strsep(&s, " \t");
-	s = skip_spaces(s);
-	if (!strcmp(st, "raw")) {
+	if (argc != 3)
+		return -EINVAL;
+
+	if (!strcmp(argv[0], "raw")) {
 		dfu->layout = DFU_RAW_ADDR;
-		dfu->data.nand.start = hextoul(s, &s);
-		if (!isspace(*s))
-			return -1;
-		s = skip_spaces(s);
-		dfu->data.nand.size = hextoul(s, &s);
-	} else if ((!strcmp(st, "part")) || (!strcmp(st, "partubi"))) {
+		dfu->data.nand.start = hextoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
+		dfu->data.nand.size = hextoul(argv[2], &s);
+		if (*s)
+			return -EINVAL;
+	} else if ((!strcmp(argv[0], "part")) || (!strcmp(argv[0], "partubi"))) {
 		char mtd_id[32];
 		struct mtd_device *mtd_dev;
 		u8 part_num;
@@ -218,11 +220,12 @@ int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr, char *s)
 
 		dfu->layout = DFU_RAW_ADDR;
 
-		dev = dectoul(s, &s);
-		if (!isspace(*s))
-			return -1;
-		s = skip_spaces(s);
-		part = dectoul(s, &s);
+		dev = dectoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
+		part = dectoul(argv[2], &s);
+		if (*s)
+			return -EINVAL;
 
 		sprintf(mtd_id, "%s%d,%d", "nand", dev, part - 1);
 		debug("using id '%s'\n", mtd_id);
@@ -237,10 +240,10 @@ int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr, char *s)
 
 		dfu->data.nand.start = pi->offset;
 		dfu->data.nand.size = pi->size;
-		if (!strcmp(st, "partubi"))
+		if (!strcmp(argv[0], "partubi"))
 			dfu->data.nand.ubi = 1;
 	} else {
-		printf("%s: Memory layout (%s) not supported!\n", __func__, st);
+		printf("%s: Memory layout (%s) not supported!\n", __func__, argv[0]);
 		return -1;
 	}
 
diff --git a/drivers/dfu/dfu_ram.c b/drivers/dfu/dfu_ram.c
index 361a3ff8af..9d10303164 100644
--- a/drivers/dfu/dfu_ram.c
+++ b/drivers/dfu/dfu_ram.c
@@ -54,18 +54,13 @@ static int dfu_read_medium_ram(struct dfu_entity *dfu, u64 offset,
 	return dfu_transfer_medium_ram(DFU_OP_READ, dfu, offset, buf, len);
 }
 
-int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
-	const char *argv[3];
-	const char **parg = argv;
-
-	for (; parg < argv + sizeof(argv) / sizeof(*argv); ++parg) {
-		*parg = strsep(&s, " \t");
-		if (*parg == NULL) {
-			pr_err("Invalid number of arguments.\n");
-			return -ENODEV;
-		}
-		s = skip_spaces(s);
+	char *s;
+
+	if (argc != 3) {
+		pr_err("Invalid number of arguments.\n");
+		return -EINVAL;
 	}
 
 	dfu->dev_type = DFU_DEV_RAM;
@@ -75,8 +70,12 @@ int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr, char *s)
 	}
 
 	dfu->layout = DFU_RAM_ADDR;
-	dfu->data.ram.start = hextoul(argv[1], NULL);
-	dfu->data.ram.size = hextoul(argv[2], NULL);
+	dfu->data.ram.start = hextoul(argv[1], &s);
+	if (*s)
+		return -EINVAL;
+	dfu->data.ram.size = hextoul(argv[2], &s);
+	if (*s)
+		return -EINVAL;
 
 	dfu->write_medium = dfu_write_medium_ram;
 	dfu->get_medium_size = dfu_get_medium_size_ram;
diff --git a/drivers/dfu/dfu_sf.c b/drivers/dfu/dfu_sf.c
index 993e951bc3..25a9c81850 100644
--- a/drivers/dfu/dfu_sf.c
+++ b/drivers/dfu/dfu_sf.c
@@ -166,9 +166,9 @@ static struct spi_flash *parse_dev(char *devstr)
 	return dev;
 }
 
-int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
-	char *st;
+	char *s;
 	char *devstr_bkup = strdup(devstr);
 
 	dfu->data.sf.dev = parse_dev(devstr_bkup);
@@ -179,17 +179,18 @@ int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char *s)
 	dfu->dev_type = DFU_DEV_SF;
 	dfu->max_buf_size = dfu->data.sf.dev->sector_size;
 
-	st = strsep(&s, " \t");
-	s = skip_spaces(s);
-	if (!strcmp(st, "raw")) {
+	if (argc != 3)
+		return -EINVAL;
+	if (!strcmp(argv[0], "raw")) {
 		dfu->layout = DFU_RAW_ADDR;
-		dfu->data.sf.start = hextoul(s, &s);
-		if (!isspace(*s))
-			return -1;
-		s = skip_spaces(s);
-		dfu->data.sf.size = hextoul(s, &s);
+		dfu->data.sf.start = hextoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
+		dfu->data.sf.size = hextoul(argv[2], &s);
+		if (*s)
+			return -EINVAL;
 	} else if (CONFIG_IS_ENABLED(DFU_SF_PART) &&
-		   (!strcmp(st, "part") || !strcmp(st, "partubi"))) {
+		   (!strcmp(argv[0], "part") || !strcmp(argv[0], "partubi"))) {
 		char mtd_id[32];
 		struct mtd_device *mtd_dev;
 		u8 part_num;
@@ -198,11 +199,12 @@ int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char *s)
 
 		dfu->layout = DFU_RAW_ADDR;
 
-		dev = dectoul(s, &s);
-		if (!isspace(*s))
-			return -1;
-		s = skip_spaces(s);
-		part = dectoul(s, &s);
+		dev = dectoul(argv[1], &s);
+		if (*s)
+			return -EINVAL;
+		part = dectoul(argv[2], &s);
+		if (*s)
+			return -EINVAL;
 
 		sprintf(mtd_id, "%s%d,%d", "nor", dev, part - 1);
 		printf("using id '%s'\n", mtd_id);
@@ -216,10 +218,10 @@ int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char *s)
 		}
 		dfu->data.sf.start = pi->offset;
 		dfu->data.sf.size = pi->size;
-		if (!strcmp(st, "partubi"))
+		if (!strcmp(argv[0], "partubi"))
 			dfu->data.sf.ubi = 1;
 	} else {
-		printf("%s: Memory layout (%s) not supported!\n", __func__, st);
+		printf("%s: Memory layout (%s) not supported!\n", __func__, argv[0]);
 		spi_flash_free(dfu->data.sf.dev);
 		return -1;
 	}
diff --git a/drivers/dfu/dfu_virt.c b/drivers/dfu/dfu_virt.c
index 80c99cb06e..29f7a08f67 100644
--- a/drivers/dfu/dfu_virt.c
+++ b/drivers/dfu/dfu_virt.c
@@ -32,10 +32,13 @@ int __weak dfu_read_medium_virt(struct dfu_entity *dfu, u64 offset,
 	return 0;
 }
 
-int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr, char *s)
+int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr, char **argv, int argc)
 {
 	debug("%s: devstr = %s\n", __func__, devstr);
 
+	if (argc != 0)
+		return -EINVAL;
+
 	dfu->dev_type = DFU_DEV_VIRT;
 	dfu->layout = DFU_RAW_ADDR;
 	dfu->data.virt.dev_num = dectoul(devstr, NULL);
diff --git a/include/dfu.h b/include/dfu.h
index f6868982df..dcb9cd9d79 100644
--- a/include/dfu.h
+++ b/include/dfu.h
@@ -432,11 +432,15 @@ static inline void dfu_set_defer_flush(struct dfu_entity *dfu)
 int dfu_write_from_mem_addr(struct dfu_entity *dfu, void *buf, int size);
 
 /* Device specific */
+/* Each entity has 5 arguments in maximum. */
+#define DFU_MAX_ENTITY_ARGS	5
+
 #if CONFIG_IS_ENABLED(DFU_MMC)
-extern int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr, char *s);
+extern int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr,
+			       char **argv, int argc);
 #else
 static inline int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr,
-				      char *s)
+				      char **argv, int argc)
 {
 	puts("MMC support not available!\n");
 	return -1;
@@ -444,10 +448,11 @@ static inline int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *devstr,
 #endif
 
 #if CONFIG_IS_ENABLED(DFU_NAND)
-extern int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr, char *s);
+extern int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr,
+				char **argv, int argc);
 #else
 static inline int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr,
-				       char *s)
+				       char **argv, int argc)
 {
 	puts("NAND support not available!\n");
 	return -1;
@@ -455,10 +460,11 @@ static inline int dfu_fill_entity_nand(struct dfu_entity *dfu, char *devstr,
 #endif
 
 #if CONFIG_IS_ENABLED(DFU_RAM)
-extern int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr, char *s);
+extern int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr,
+			       char **argv, int argc);
 #else
 static inline int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr,
-				      char *s)
+				      char **argv, int argc)
 {
 	puts("RAM support not available!\n");
 	return -1;
@@ -466,10 +472,11 @@ static inline int dfu_fill_entity_ram(struct dfu_entity *dfu, char *devstr,
 #endif
 
 #if CONFIG_IS_ENABLED(DFU_SF)
-extern int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr, char *s);
+extern int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr,
+			      char **argv, int argc);
 #else
 static inline int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr,
-				     char *s)
+				     char **argv, int argc)
 {
 	puts("SF support not available!\n");
 	return -1;
@@ -477,10 +484,11 @@ static inline int dfu_fill_entity_sf(struct dfu_entity *dfu, char *devstr,
 #endif
 
 #if CONFIG_IS_ENABLED(DFU_MTD)
-int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr, char *s);
+extern int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr,
+			       char **argv, int argc);
 #else
 static inline int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr,
-				      char *s)
+				      char **argv, int argc)
 {
 	puts("MTD support not available!\n");
 	return -1;
@@ -488,7 +496,8 @@ static inline int dfu_fill_entity_mtd(struct dfu_entity *dfu, char *devstr,
 #endif
 
 #ifdef CONFIG_DFU_VIRT
-int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr, char *s);
+int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr,
+			 char **argv, int argc);
 int dfu_write_medium_virt(struct dfu_entity *dfu, u64 offset,
 			  void *buf, long *len);
 int dfu_get_medium_size_virt(struct dfu_entity *dfu, u64 *size);
@@ -496,7 +505,7 @@ int dfu_read_medium_virt(struct dfu_entity *dfu, u64 offset,
 			 void *buf, long *len);
 #else
 static inline int dfu_fill_entity_virt(struct dfu_entity *dfu, char *devstr,
-				       char *s)
+				       char **argv, int argc)
 {
 	puts("VIRT support not available!\n");
 	return -1;
