[U-Boot-Users] [PATCH] NAND feature update

[Ladislav Michl <ladis@linux-mips.org>]

Hi Stefan,

On Sat, Oct 21, 2006 at 12:32:24PM +0200, Stefan Roese wrote:
> > @@ -83,50 +92,70 @@ static int nand_dump(nand_info_t *nand, 
> >  
> >  /* ------------------------------------------------------------------------- */
> >  
> > -static void
> > -arg_off_size(int argc, char *argv[], ulong *off, ulong *size, ulong totsize)
> > +static int str2long(char *p, ulong *num)
> 
> Please either remove this small helper function are make it inline.

Marked inline.

> > @@ -181,7 +210,7 @@ int do_nand(cmd_tbl_t * cmdtp, int flag,
> >  		return 0;
> >  	}
> >  
> > -	if (strcmp(cmd, "bad") != 0 && strcmp(cmd, "erase") != 0 &&
> > +	if (strcmp(cmd, "bad") != 0 && strncmp(cmd, "erase", 3) != 0 &&
> 
> Please don't change the check on "erase" here. The string should match
> completely and not only the first 3 chars.

Change removed (I wanted to save myself some typing and make it the same
as erase (era) command).

> >  		nand_erase_options_t opts;
> >  		int clean = argc >= 3 && !strcmp("clean", argv[2]);
> > -		int rest_argc = argc - 2;
> > -		char **rest_argv = argv + 2;
> > +		int o = clean ? 3 : 2;
> >  		int scrub = !strcmp(cmd, "scrub");
> >  
> > -		if (clean) {
> > -			rest_argc--;
> > -			rest_argv++;
> > -		}
> > -
> > -		if (rest_argc == 0) {
> > -
> > -			printf("\nNAND %s: device %d whole chip\n",
> > -			       cmd,
> > -			       nand_curr_device);
> > -
> > -			off = size = 0;
> > -		} else {
> > -			arg_off_size(rest_argc, rest_argv, &off, &size,
> > -				     nand->size);
> > -
> > -			if (off == 0 && size == 0)
> > -				return 1;
> > -
> > -			printf("\nNAND %s: device %d offset 0x%x, size 0x%x\n",
> > -			       cmd, nand_curr_device, off, size);
> > -		}
> > +		printf("\nNAND %s: ", scrub ? "scrub" : "erase");
> > +		if (arg_off_size(argc - o, argv + o, nand, &off, &size) != 0)
> > +			return 1;
> 
> This seems quite obscure (at least to Wolfgang and me ;-)). Could you please
> either make the code a little more "readable", or at least add some comments
> here. Thanks.

Yes, we already had that debate, but I forgot to add comments to this
patch. Readded.

> >  
> >  		memset(&opts, 0, sizeof(opts));
> >  		opts.offset = off;
> > @@ -242,23 +251,23 @@ int do_nand(cmd_tbl_t * cmdtp, int flag,
> >  		opts.quiet  = quiet;
> >  
> >  		if (scrub) {
> > -			printf("Warning: "
> > -			       "scrub option will erase all factory set "
> > -			       "bad blocks!\n"
> > -			       "	 "
> > -			       "There is no reliable way to recover them.\n"
> > -			       "	 "
> > -			       "Use this command only for testing purposes "
> > -			       "if you\n"
> > -			       "	 "
> > -			       "are sure of what you are doing!\n"
> > -			       "\nReally scrub this NAND flash? <y/N>\n"
> > -				);
> > +			puts("Warning: "
> > +			     "scrub option will erase all factory set "
> > +			     "bad blocks!\n"
> > +			     "         "
> > +			     "There is no reliable way to recover them.\n"
> > +			     "         "
> > +			     "Use this command only for testing purposes "
> > +			     "if you\n"
> > +			     "         "
> > +			     "are sure of what you are doing!\n"
> > +			     "\nReally scrub this NAND flash? <y/N>\n"
> > +			    );
> 
> Indentation with TAB's please.

Indenting with TABs really doesn't improve readability. Original code
uses this style indentation, so I kept it. Anyway, I can send it as
separate patch to make it consistent over whole file.

> > @@ -404,9 +408,9 @@ int do_nand(cmd_tbl_t * cmdtp, int flag,
> >  		       }
> >  		} else {
> >  			if (!nand_lock(nand, tight)) {
> > -				printf ("NAND flash successfully locked\n");
> > +				puts("NAND flash successfully locked\n");
> >  			} else {
> > -				printf ("Error locking NAND flash. \n");
> > +				puts("Error locking NAND flash. \n");
> 
> Please remove the space after the ".". Thanks.

Fixed.

> > @@ -414,19 +418,14 @@ int do_nand(cmd_tbl_t * cmdtp, int flag,
> >  	}
> >  
> >  	if (strcmp(cmd, "unlock") == 0) {
> > -		if (argc == 2) {
> > -			off = 0;
> > -			size = nand->size;
> > -		} else {
> > -			arg_off_size(argc - 2, argv + 2, &off, &size,
> > -				     nand->size);
> > -		}
> > +		if (arg_off_size(argc - 2, argv + 2, nand, &off, &size) < 0)
> > +			return 1;
> >  
> >  		if (!nand_unlock(nand, off, size)) {
> > -			printf("NAND flash successfully unlocked\n");
> > +			puts("NAND flash successfully unlocked\n");
> >  		} else {
> > -			printf("Error unlocking NAND flash. "
> > -			       "Write and erase will probably fail\n");
> > +			puts("Error unlocking NAND flash. "
> 
> Please remove the space after the ".". Thanks.

This is multiline string. "... NAND flash. Write and..." reads better
with space.

Here is an updated patch.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>

CHANGELOG
* Patch by Ladislav Michl, 23 Oct 2006:
  chpart, nboot and NAND subsystem related commands now accept also
  partition name to specify offset.

diff --git a/common/cmd_jffs2.c b/common/cmd_jffs2.c
index b5fd417..7fd1fa3 100644
--- a/common/cmd_jffs2.c
+++ b/common/cmd_jffs2.c
@@ -1300,7 +1300,7 @@ static void list_partitions(void)
  * Given partition identifier in form of <dev_type><dev_num>,<part_num> find
  * corresponding device and verify partition number.
  *
- * @param id string describing device and partition
+ * @param id string describing device and partition or partition name
  * @param dev pointer to the requested device (output)
  * @param part_num verified partition number (output)
  * @param part pointer to requested partition (output)
@@ -1309,11 +1309,23 @@ static void list_partitions(void)
 int find_dev_and_part(const char *id, struct mtd_device **dev,
 		u8 *part_num, struct part_info **part)
 {
+	struct list_head *dentry, *pentry;
 	u8 type, dnum, pnum;
 	const char *p;
 
 	DEBUGF("--- find_dev_and_part ---\nid = %s\n", id);
 
+	list_for_each(dentry, &devices) {
+		*part_num = 0;
+		*dev = list_entry(dentry, struct mtd_device, link);
+		list_for_each(pentry, &(*dev)->parts) {
+			*part = list_entry(pentry, struct part_info, link);
+			if (strcmp((*part)->name, id) == 0)
+				return 0;
+			(*part_num)++;
+		}
+	}
+
 	p = id;
 	*dev = NULL;
 	*part = NULL;
diff --git a/common/cmd_nand.c b/common/cmd_nand.c
index 4fb3b65..446e7b8 100644
--- a/common/cmd_nand.c
+++ b/common/cmd_nand.c
@@ -36,6 +36,15 @@ #endif
 #include <jffs2/jffs2.h>
 #include <nand.h>
 
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2) && defined(CONFIG_JFFS2_CMDLINE)
+
+/* parition handling routines */
+int mtdparts_init(void);
+int id_parse(const char *id, const char **ret_id, u8 *dev_type, u8 *dev_num);
+int find_dev_and_part(const char *id, struct mtd_device **dev,
+		u8 *part_num, struct part_info **part);
+#endif
+
 extern nand_info_t nand_info[];       /* info for NAND chips */
 
 static int nand_dump_oob(nand_info_t *nand, ulong off)
@@ -83,50 +92,70 @@ static int nand_dump(nand_info_t *nand, 
 
 /* ------------------------------------------------------------------------- */
 
-static void
-arg_off_size(int argc, char *argv[], ulong *off, ulong *size, ulong totsize)
+static inline int str2long(char *p, ulong *num)
 {
-	*off = 0;
-	*size = 0;
+	char *endptr;
 
-#if defined(CONFIG_JFFS2_NAND) && defined(CFG_JFFS_CUSTOM_PART)
-	if (argc >= 1 && strcmp(argv[0], "partition") == 0) {
-		int part_num;
-		struct part_info *part;
-		const char *partstr;
-
-		if (argc >= 2)
-			partstr = argv[1];
-		else
-			partstr = getenv("partition");
-
-		if (partstr)
-			part_num = (int)simple_strtoul(partstr, NULL, 10);
-		else
-			part_num = 0;
+	*num = simple_strtoul(p, &endptr, 16);
+	return (*p != '\0' && *endptr == '\0') ? 1 : 0;
+}
 
-		part = jffs2_part_info(part_num);
-		if (part == NULL) {
-			printf("\nInvalid partition %d\n", part_num);
-			return;
+static int
+arg_off_size(int argc, char *argv[], nand_info_t *nand, ulong *off, ulong *size)
+{
+	int idx = nand_curr_device;
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2) && defined(CONFIG_JFFS2_CMDLINE)
+	struct mtd_device *dev;
+	struct part_info *part;
+	u8 pnum;
+
+	if (argc >= 1 && !(str2long(argv[0], off))) {
+		if ((mtdparts_init() == 0) &&
+		    (find_dev_and_part(argv[0], &dev, &pnum, &part) == 0)) {
+			if (dev->id->type != MTD_DEV_TYPE_NAND) {
+				puts("not a NAND device\n");
+				return -1;
+			}
+			*off = part->offset;
+			if (argc >= 2) {
+				if (!(str2long(argv[1], size))) {
+					printf("'%s' is not a number\n", argv[1]);
+					return -1;
+				}
+				if (*size > part->size)
+					*size = part->size;
+			} else
+				*size = part->size;
+			idx = dev->id->num;
+			*nand = nand_info[idx];
+			goto out;
 		}
-		*size = part->size;
-		*off = (ulong)part->offset;
-	} else
+	}
 #endif
-	{
-		if (argc >= 1)
-			*off = (ulong)simple_strtoul(argv[0], NULL, 16);
-		else
-			*off = 0;
-
-		if (argc >= 2)
-			*size = (ulong)simple_strtoul(argv[1], NULL, 16);
-		else
-			*size = totsize - *off;
 
-	}
+	if (argc >= 1) {
+		if (!(str2long(argv[0], off))) {
+			printf("'%s' is not a number\n", argv[0]);
+			return -1;
+		}
+	} else
+		*off = 0;
 
+	if (argc >= 2) {
+		if (!(str2long(argv[1], size))) {
+			printf("'%s' is not a number\n", argv[1]);
+			return -1;
+		}
+	} else
+		*size = nand->size - *off;
+
+out:
+	printf("device %d ", idx);
+	if (*size == nand->size)
+		puts("whole chip\n");
+	else
+		printf("offset 0x%x, size 0x%x\n", *off, *size);
+	return 0;
 }
 
 int do_nand(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
@@ -213,35 +242,22 @@ #endif
 		return 0;
 	}
 
+	/*
+	 * Syntax is:
+	 *   0    1     2       3    4
+	 *   nand erase [clean] [off size]
+	 */
 	if (strcmp(cmd, "erase") == 0 || strcmp(cmd, "scrub") == 0) {
 		nand_erase_options_t opts;
-		int clean = argc >= 3 && !strcmp("clean", argv[2]);
-		int rest_argc = argc - 2;
-		char **rest_argv = argv + 2;
+		/* "clean" at index 2 means request to write cleanmarker */
+		int clean = argc > 2 && !strcmp("clean", argv[2]);
+		int o = clean ? 3 : 2;
 		int scrub = !strcmp(cmd, "scrub");
 
-		if (clean) {
-			rest_argc--;
-			rest_argv++;
-		}
-
-		if (rest_argc == 0) {
-
-			printf("\nNAND %s: device %d whole chip\n",
-			       cmd,
-			       nand_curr_device);
-
-			off = size = 0;
-		} else {
-			arg_off_size(rest_argc, rest_argv, &off, &size,
-				     nand->size);
-
-			if (off == 0 && size == 0)
-				return 1;
-
-			printf("\nNAND %s: device %d offset 0x%x, size 0x%x\n",
-			       cmd, nand_curr_device, off, size);
-		}
+		printf("\nNAND %s: ", scrub ? "scrub" : "erase");
+		/* skip first two or three arguments, look for offset and size */
+		if (arg_off_size(argc - o, argv + o, nand, &off, &size) != 0)
+			return 1;
 
 		memset(&opts, 0, sizeof(opts));
 		opts.offset = off;
@@ -250,23 +266,23 @@ #endif
 		opts.quiet  = quiet;
 
 		if (scrub) {
-			printf("Warning: "
-			       "scrub option will erase all factory set "
-			       "bad blocks!\n"
-			       "	 "
-			       "There is no reliable way to recover them.\n"
-			       "	 "
-			       "Use this command only for testing purposes "
-			       "if you\n"
-			       "	 "
-			       "are sure of what you are doing!\n"
-			       "\nReally scrub this NAND flash? <y/N>\n"
-				);
+			puts("Warning: "
+			     "scrub option will erase all factory set "
+			     "bad blocks!\n"
+			     "         "
+			     "There is no reliable way to recover them.\n"
+			     "         "
+			     "Use this command only for testing purposes "
+			     "if you\n"
+			     "         "
+			     "are sure of what you are doing!\n"
+			     "\nReally scrub this NAND flash? <y/N>\n"
+			    );
 
 			if (getc() == 'y' && getc() == '\r') {
 				opts.scrub = 1;
 			} else {
-				printf("scrub aborted\n");
+				puts("scrub aborted\n");
 				return -1;
 			}
 		}
@@ -301,13 +317,10 @@ #endif
 
 		addr = (ulong)simple_strtoul(argv[2], NULL, 16);
 
-		arg_off_size(argc - 3, argv + 3, &off, &size, nand->size);
-		if (off == 0 && size == 0)
-			return 1;
-
 		read = strncmp(cmd, "read", 4) == 0; /* 1 = read, 0 = write */
-		printf("\nNAND %s: device %d offset %u, size %u ... ",
-		       read ? "read" : "write", nand_curr_device, off, size);
+		printf("\nNAND %s: ", read ? "read" : "write");
+		if (arg_off_size(argc - 3, argv + 3, nand, &off, &size) != 0)
+			return 1;
 
 		s = strchr(cmd, '.');
 		if (s != NULL &&
@@ -334,15 +347,13 @@ #endif
 				opts.quiet      = quiet;
 				ret = nand_write_opts(nand, &opts);
 			}
-			printf("%s\n", ret ? "ERROR" : "OK");
-			return ret == 0 ? 0 : 1;
+		} else {
+			if (read)
+				ret = nand_read(nand, off, &size, (u_char *)addr);
+			else
+				ret = nand_write(nand, off, &size, (u_char *)addr);
 		}
 
-		if (read)
-			ret = nand_read(nand, off, &size, (u_char *)addr);
-		else
-			ret = nand_write(nand, off, &size, (u_char *)addr);
-
 		printf(" %d bytes %s: %s\n", size,
 		       read ? "read" : "written", ret ? "ERROR" : "OK");
 
@@ -412,9 +423,9 @@ #endif
 		       }
 		} else {
 			if (!nand_lock(nand, tight)) {
-				printf ("NAND flash successfully locked\n");
+				puts("NAND flash successfully locked\n");
 			} else {
-				printf ("Error locking NAND flash. \n");
+				puts("Error locking NAND flash\n");
 				return 1;
 			}
 		}
@@ -422,19 +433,14 @@ #endif
 	}
 
 	if (strcmp(cmd, "unlock") == 0) {
-		if (argc == 2) {
-			off = 0;
-			size = nand->size;
-		} else {
-			arg_off_size(argc - 2, argv + 2, &off, &size,
-				     nand->size);
-		}
+		if (arg_off_size(argc - 2, argv + 2, nand, &off, &size) < 0)
+			return 1;
 
 		if (!nand_unlock(nand, off, size)) {
-			printf("NAND flash successfully unlocked\n");
+			puts("NAND flash successfully unlocked\n");
 		} else {
-			printf("Error unlocking NAND flash. "
-			       "Write and erase will probably fail\n");
+			puts("Error unlocking NAND flash, "
+			     "write and erase will probably fail\n");
 			return 1;
 		}
 		return 0;
@@ -449,8 +455,8 @@ U_BOOT_CMD(nand, 5, 1, do_nand,
 	"nand    - NAND sub-system\n",
 	"info                  - show available NAND devices\n"
 	"nand device [dev]     - show or set current device\n"
-	"nand read[.jffs2]     - addr off size\n"
-	"nand write[.jffs2]    - addr off size - read/write `size' bytes starting\n"
+	"nand read[.jffs2]     - addr off|partition size\n"
+	"nand write[.jffs2]    - addr off|partiton size - read/write `size' bytes starting\n"
 	"   @offset `off' to/from memory address `addr'\n"
 	"nand erase [clean] [off size] - erase `size' bytes from\n"
 	"    offset `off' (entire device if not specified)\n"
@@ -462,62 +468,20 @@ U_BOOT_CMD(nand, 5, 1, do_nand,
 	"nand lock [tight] [status] - bring nand to lock state or display locked pages\n"
 	"nand unlock [offset] [size] - unlock section\n");
 
-int do_nandboot(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+static int nand_load_image(cmd_tbl_t *cmdtp, nand_info_t *nand,
+			   ulong offset, ulong addr, char *cmd)
 {
-	char *boot_device = NULL;
-	char *ep;
-	int dev;
 	int r;
-	ulong addr, cnt, offset = 0;
+	char *ep;
+	ulong cnt;
 	image_header_t *hdr;
-	nand_info_t *nand;
 
-	switch (argc) {
-	case 1:
-		addr = CFG_LOAD_ADDR;
-		boot_device = getenv("bootdevice");
-		break;
-	case 2:
-		addr = simple_strtoul(argv[1], NULL, 16);
-		boot_device = getenv("bootdevice");
-		break;
-	case 3:
-		addr = simple_strtoul(argv[1], NULL, 16);
-		boot_device = argv[2];
-		break;
-	case 4:
-		addr = simple_strtoul(argv[1], NULL, 16);
-		boot_device = argv[2];
-		offset = simple_strtoul(argv[3], NULL, 16);
-		break;
-	default:
-		printf("Usage:\n%s\n", cmdtp->usage);
-		SHOW_BOOT_PROGRESS(-1);
-		return 1;
-	}
-
-	if (!boot_device) {
-		puts("\n** No boot device **\n");
-		SHOW_BOOT_PROGRESS(-1);
-		return 1;
-	}
-
-	dev = simple_strtoul(boot_device, &ep, 16);
-
-	if (dev < 0 || dev >= CFG_MAX_NAND_DEVICE || !nand_info[dev].name) {
-		printf("\n** Device %d not available\n", dev);
-		SHOW_BOOT_PROGRESS(-1);
-		return 1;
-	}
-
-	nand = &nand_info[dev];
-	printf("\nLoading from device %d: %s (offset 0x%lx)\n",
-	       dev, nand->name, offset);
+	printf("\nLoading from %s, offset 0x%lx\n", nand->name, offset);
 
 	cnt = nand->oobblock;
 	r = nand_read(nand, offset, &cnt, (u_char *) addr);
 	if (r) {
-		printf("** Read error on %d\n", dev);
+		puts("** Read error\n");
 		SHOW_BOOT_PROGRESS(-1);
 		return 1;
 	}
@@ -536,7 +500,7 @@ int do_nandboot(cmd_tbl_t * cmdtp, int f
 
 	r = nand_read(nand, offset, &cnt, (u_char *) addr);
 	if (r) {
-		printf("** Read error on %d\n", dev);
+		puts("** Read error\n");
 		SHOW_BOOT_PROGRESS(-1);
 		return 1;
 	}
@@ -550,7 +514,7 @@ int do_nandboot(cmd_tbl_t * cmdtp, int f
 		char *local_args[2];
 		extern int do_bootm(cmd_tbl_t *, int, int, char *[]);
 
-		local_args[0] = argv[0];
+		local_args[0] = cmd;
 		local_args[1] = NULL;
 
 		printf("Automatic boot of image at addr 0x%08lx ...\n", addr);
@@ -561,9 +525,81 @@ int do_nandboot(cmd_tbl_t * cmdtp, int f
 	return 0;
 }
 
-U_BOOT_CMD(nboot, 4, 1, do_nandboot,
-	"nboot   - boot from NAND device\n", "loadAddr dev\n");
+int do_nandboot(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+{
+	char *boot_device = NULL;
+	int idx;
+	ulong addr, offset = 0;
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2) && defined(CONFIG_JFFS2_CMDLINE)
+	struct mtd_device *dev;
+	struct part_info *part;
+	u8 pnum;
+
+	if (argc >= 2) {
+		char *p = (argc == 2) ? argv[1] : argv[2];
+		if (!(str2long(p, &addr)) && (mtdparts_init() == 0) &&
+		    (find_dev_and_part(p, &dev, &pnum, &part) == 0)) {
+			if (dev->id->type != MTD_DEV_TYPE_NAND) {
+				puts("Not a NAND device\n");
+				return 1;
+			}
+			if (argc > 3)
+				goto usage;
+			if (argc == 3)
+				addr = simple_strtoul(argv[2], NULL, 16);
+			else
+				addr = CFG_LOAD_ADDR;
+			return nand_load_image(cmdtp, &nand_info[dev->id->num],
+					       part->offset, addr, argv[0]);
+		}
+	}
+#endif
+
+	switch (argc) {
+	case 1:
+		addr = CFG_LOAD_ADDR;
+		boot_device = getenv("bootdevice");
+		break;
+	case 2:
+		addr = simple_strtoul(argv[1], NULL, 16);
+		boot_device = getenv("bootdevice");
+		break;
+	case 3:
+		addr = simple_strtoul(argv[1], NULL, 16);
+		boot_device = argv[2];
+		break;
+	case 4:
+		addr = simple_strtoul(argv[1], NULL, 16);
+		boot_device = argv[2];
+		offset = simple_strtoul(argv[3], NULL, 16);
+		break;
+	default:
+usage:
+		printf("Usage:\n%s\n", cmdtp->usage);
+		SHOW_BOOT_PROGRESS(-1);
+		return 1;
+	}
+
+	if (!boot_device) {
+		puts("\n** No boot device **\n");
+		SHOW_BOOT_PROGRESS(-1);
+		return 1;
+	}
+
+	idx = simple_strtoul(boot_device, NULL, 16);
 
+	if (idx < 0 || idx >= CFG_MAX_NAND_DEVICE || !nand_info[idx].name) {
+		printf("\n** Device %d not available\n", idx);
+		SHOW_BOOT_PROGRESS(-1);
+		return 1;
+	}
+
+	return nand_load_image(cmdtp, &nand_info[idx], offset, addr, argv[0]);
+}
+
+U_BOOT_CMD(nboot, 4, 1, do_nandboot,
+	"nboot   - boot from NAND device\n",
+	"[partition] | [[[loadAddr] dev] offset]\n");
 
 #endif				/* (CONFIG_COMMANDS & CFG_CMD_NAND) */
 
diff --git a/doc/README.nand b/doc/README.nand
index 5279a4f..b5171f4 100644
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -34,14 +34,19 @@ Commands:
    nand device num
       Make device `num' the current device and print information about it.
 
-   nand erase off size
-   nand erase clean [off size]
-      Erase `size' bytes starting at offset `off'.  Only complete erase
-      blocks can be erased.
+   nand erase off|partition size
+   nand erase clean [off|partition size]
+      Erase `size' bytes starting at offset `off'. Alternatively partition
+      name can be specified, in this case size will be eventually limited
+      to not exceed partition size (this behaviour applies also to read
+      and write commands). Only complete erase blocks can be erased.
+
+      If `erase' is specified without an offset or size, the entire flash
+      is erased. If `erase' is specified with partition but without an
+      size, the entire partition is erased.
 
       If `clean' is specified, a JFFS2-style clean marker is written to
-      each block after it is erased. If `clean' is specified without an
-      offset or size, the entire flash is erased.
+      each block after it is erased.
 
       This command will not erase blocks that are marked bad. There is
       a debug option in cmd_nand.c to allow bad blocks to be erased.
@@ -51,28 +56,28 @@ Commands:
    nand info
       Print information about all of the NAND devices found.
 
-   nand read addr ofs size
+   nand read addr ofs|partition size
       Read `size' bytes from `ofs' in NAND flash to `addr'. If a page
       cannot be read because it is marked bad or an uncorrectable data
       error is found the command stops with an error.
 
-   nand read.jffs2 addr ofs size
+   nand read.jffs2 addr ofs|partition size
       Like `read', but the data for blocks that are marked bad is read as
       0xff. This gives a readable JFFS2 image that can be processed by
       the JFFS2 commands such as ls and fsload.
 
-   nand read.oob addr ofs size
+   nand read.oob addr ofs|partition size
       Read `size' bytes from the out-of-band data area corresponding to
       `ofs' in NAND flash to `addr'. This is limited to the 16 bytes of
       data for one 512-byte page or 2 256-byte pages. There is no check
       for bad blocks or ECC errors.
 
-   nand write addr ofs size
+   nand write addr ofs|partition size
       Write `size' bytes from `addr' to `ofs' in NAND flash. If a page
       cannot be written because it is marked bad or the write fails the
       command stops with an error.
 
-   nand write.jffs2 addr ofs size
+   nand write.jffs2 addr ofs|partition size
       Like `write', but blocks that are marked bad are skipped and the
       is written to the next block instead. This allows writing writing
       a JFFS2 image, as long as the image is short enough to fit even
@@ -80,7 +85,7 @@ Commands:
       produced by mkfs.jffs2 should work well, but loading an image copied
       from another flash is going to be trouble if there are any bad blocks.
 
-   nand write.oob addr ofs size
+   nand write.oob addr ofs|partition size
       Write `size' bytes from `addr' to the out-of-band data area
       corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
       of data for one 512-byte page or 2 256-byte pages. There is no check
diff --git a/drivers/nand/nand_util.c b/drivers/nand/nand_util.c
index 7570210..10bf036 100644
--- a/drivers/nand/nand_util.c
+++ b/drivers/nand/nand_util.c
@@ -83,15 +83,8 @@ int nand_erase_opts(nand_info_t *meminfo
 
 	erase.mtd = meminfo;
 	erase.len  = meminfo->erasesize;
-	if (opts->offset == 0 && opts->length == 0) {
-		/* erase complete chip */
-		erase.addr = 0;
-		erase_length = meminfo->size;
-	} else {
-		/* erase specified region */
-		erase.addr = opts->offset;
-		erase_length = opts->length;
-	}
+	erase.addr = opts->offset;
+	erase_length = opts->length;
 
 	isNAND = meminfo->type == MTD_NANDFLASH ? 1 : 0;