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wdenk7a8e9bed2003-05-31 18:35:21 +00001NAND FLASH commands and notes
2
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +01003See NOTE below!!!
4
wdenk7a8e9bed2003-05-31 18:35:21 +00005# (C) Copyright 2003
6# Dave Ellis, SIXNET, dge@sixnetio.com
7#
8# See file CREDITS for list of people who contributed to this
9# project.
10#
11# This program is free software; you can redistribute it and/or
12# modify it under the terms of the GNU General Public License as
13# published by the Free Software Foundation; either version 2 of
14# the License, or (at your option) any later version.
15#
16# This program is distributed in the hope that it will be useful,
17# but WITHOUT ANY WARRANTY; without even the implied warranty of
18# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19# GNU General Public License for more details.
20#
21# You should have received a copy of the GNU General Public License
22# along with this program; if not, write to the Free Software
23# Foundation, Inc., 59 Temple Place, Suite 330, Boston,
24# MA 02111-1307 USA
25
26Commands:
27
28 nand bad
29 Print a list of all of the bad blocks in the current device.
30
31 nand device
32 Print information about the current NAND device.
33
34 nand device num
35 Make device `num' the current device and print information about it.
36
Stefan Roese856f0542006-10-28 15:55:52 +020037 nand erase off|partition size
38 nand erase clean [off|partition size]
39 Erase `size' bytes starting at offset `off'. Alternatively partition
40 name can be specified, in this case size will be eventually limited
41 to not exceed partition size (this behaviour applies also to read
42 and write commands). Only complete erase blocks can be erased.
43
44 If `erase' is specified without an offset or size, the entire flash
45 is erased. If `erase' is specified with partition but without an
46 size, the entire partition is erased.
wdenk7a8e9bed2003-05-31 18:35:21 +000047
48 If `clean' is specified, a JFFS2-style clean marker is written to
Stefan Roese856f0542006-10-28 15:55:52 +020049 each block after it is erased.
wdenk7a8e9bed2003-05-31 18:35:21 +000050
51 This command will not erase blocks that are marked bad. There is
52 a debug option in cmd_nand.c to allow bad blocks to be erased.
53 Please read the warning there before using it, as blocks marked
54 bad by the manufacturer must _NEVER_ be erased.
55
56 nand info
57 Print information about all of the NAND devices found.
58
Stefan Roese856f0542006-10-28 15:55:52 +020059 nand read addr ofs|partition size
Scott Wood984e03c2008-06-12 13:13:23 -050060 Read `size' bytes from `ofs' in NAND flash to `addr'. Blocks that
61 are marked bad are skipped. If a page cannot be read because an
62 uncorrectable data error is found, the command stops with an error.
wdenk7a8e9bed2003-05-31 18:35:21 +000063
Stefan Roese856f0542006-10-28 15:55:52 +020064 nand read.oob addr ofs|partition size
wdenk7a8e9bed2003-05-31 18:35:21 +000065 Read `size' bytes from the out-of-band data area corresponding to
66 `ofs' in NAND flash to `addr'. This is limited to the 16 bytes of
67 data for one 512-byte page or 2 256-byte pages. There is no check
68 for bad blocks or ECC errors.
69
Stefan Roese856f0542006-10-28 15:55:52 +020070 nand write addr ofs|partition size
Scott Wood984e03c2008-06-12 13:13:23 -050071 Write `size' bytes from `addr' to `ofs' in NAND flash. Blocks that
72 are marked bad are skipped. If a page cannot be read because an
73 uncorrectable data error is found, the command stops with an error.
wdenk7a8e9bed2003-05-31 18:35:21 +000074
Scott Wood984e03c2008-06-12 13:13:23 -050075 As JFFS2 skips blocks similarly, this allows writing a JFFS2 image,
76 as long as the image is short enough to fit even after skipping the
77 bad blocks. Compact images, such as those produced by mkfs.jffs2
78 should work well, but loading an image copied from another flash is
79 going to be trouble if there are any bad blocks.
wdenk7a8e9bed2003-05-31 18:35:21 +000080
Stefan Roese856f0542006-10-28 15:55:52 +020081 nand write.oob addr ofs|partition size
wdenk7a8e9bed2003-05-31 18:35:21 +000082 Write `size' bytes from `addr' to the out-of-band data area
83 corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
84 of data for one 512-byte page or 2 256-byte pages. There is no check
85 for bad blocks.
86
87Configuration Options:
88
Jon Loeligerb5501f72007-07-09 19:10:03 -050089 CONFIG_CMD_NAND
90 Enables NAND support and commmands.
wdenk7a8e9bed2003-05-31 18:35:21 +000091
92 CONFIG_MTD_NAND_ECC_JFFS2
93 Define this if you want the Error Correction Code information in
94 the out-of-band data to be formatted to match the JFFS2 file system.
95 CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for
96 someone to implement.
97
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +020098 CONFIG_SYS_MAX_NAND_DEVICE
wdenk7a8e9bed2003-05-31 18:35:21 +000099 The maximum number of NAND devices you want to support.
100
Scott Wood99067b02009-04-01 15:33:24 -0500101 CONFIG_SYS_NAND_MAX_CHIPS
102 The maximum number of NAND chips per device to be supported.
wdenk7a8e9bed2003-05-31 18:35:21 +0000103
Scott Wood99067b02009-04-01 15:33:24 -0500104 CONFIG_SYS_DAVINCI_BROKEN_ECC
Hugo Villeneuve9b05aa72008-08-30 17:06:55 -0400105 Versions of U-Boot <= 1.3.3 and Montavista Linux kernels
106 generated bogus ECCs on large-page NAND. Both large and small page
107 NAND ECCs were incompatible with the Linux davinci git tree (since
108 NAND was integrated in 2.6.24).
109 Turn this ON if you want backwards compatibility.
110 Turn this OFF if you want U-Boot and the Linux davinci git kernel
111 to use the same ECC format.
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100112
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100113NOTE:
114=====
115
Scott Wood99067b02009-04-01 15:33:24 -0500116The current NAND implementation is based on what is in recent
117Linux kernels. The old legacy implementation has been disabled,
118and will be removed soon.
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100119
Scott Wood99067b02009-04-01 15:33:24 -0500120If you have board code which used CONFIG_NAND_LEGACY, you'll need
121to convert to the current NAND interface for it to continue to work.
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100122
Scott Wood99067b02009-04-01 15:33:24 -0500123The Disk On Chip driver is currently broken and has been for some time.
124There is a driver in drivers/mtd/nand, taken from Linux, that works with
125the current NAND system but has not yet been adapted to the u-boot
126environment.
Stefan Roese2255b2d2006-10-10 12:36:02 +0200127
Stefan Roese2255b2d2006-10-10 12:36:02 +0200128Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006
129
130JFFS2 related commands:
131
132 implement "nand erase clean" and old "nand erase"
133 using both the new code which is able to skip bad blocks
134 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
135
Stefan Roese2255b2d2006-10-10 12:36:02 +0200136Miscellaneous and testing commands:
137 "markbad [offset]"
138 create an artificial bad block (for testing bad block handling)
139
140 "scrub [offset length]"
141 like "erase" but don't skip bad block. Instead erase them.
142 DANGEROUS!!! Factory set bad blocks will be lost. Use only
143 to remove artificial bad blocks created with the "markbad" command.
144
145
146NAND locking command (for chips with active LOCKPRE pin)
147
148 "nand lock"
149 set NAND chip to lock state (all pages locked)
150
151 "nand lock tight"
152 set NAND chip to lock tight state (software can't change locking anymore)
153
154 "nand lock status"
155 displays current locking status of all pages
156
157 "nand unlock [offset] [size]"
158 unlock consecutive area (can be called multiple times for different areas)
159
160
161I have tested the code with board containing 128MiB NAND large page chips
162and 32MiB small page chips.