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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#
Wolfgang Denk1a459662013-07-08 09:37:19 +02008# SPDX-License-Identifier: GPL-2.0+
wdenk7a8e9bed2003-05-31 18:35:21 +00009
10Commands:
11
12 nand bad
13 Print a list of all of the bad blocks in the current device.
14
15 nand device
16 Print information about the current NAND device.
17
18 nand device num
19 Make device `num' the current device and print information about it.
20
Stefan Roese856f0542006-10-28 15:55:52 +020021 nand erase off|partition size
22 nand erase clean [off|partition size]
23 Erase `size' bytes starting at offset `off'. Alternatively partition
24 name can be specified, in this case size will be eventually limited
25 to not exceed partition size (this behaviour applies also to read
26 and write commands). Only complete erase blocks can be erased.
27
28 If `erase' is specified without an offset or size, the entire flash
29 is erased. If `erase' is specified with partition but without an
30 size, the entire partition is erased.
wdenk7a8e9bed2003-05-31 18:35:21 +000031
32 If `clean' is specified, a JFFS2-style clean marker is written to
Stefan Roese856f0542006-10-28 15:55:52 +020033 each block after it is erased.
wdenk7a8e9bed2003-05-31 18:35:21 +000034
35 This command will not erase blocks that are marked bad. There is
36 a debug option in cmd_nand.c to allow bad blocks to be erased.
37 Please read the warning there before using it, as blocks marked
38 bad by the manufacturer must _NEVER_ be erased.
39
40 nand info
41 Print information about all of the NAND devices found.
42
Stefan Roese856f0542006-10-28 15:55:52 +020043 nand read addr ofs|partition size
Scott Wood984e03c2008-06-12 13:13:23 -050044 Read `size' bytes from `ofs' in NAND flash to `addr'. Blocks that
45 are marked bad are skipped. If a page cannot be read because an
46 uncorrectable data error is found, the command stops with an error.
wdenk7a8e9bed2003-05-31 18:35:21 +000047
Stefan Roese856f0542006-10-28 15:55:52 +020048 nand read.oob addr ofs|partition size
wdenk7a8e9bed2003-05-31 18:35:21 +000049 Read `size' bytes from the out-of-band data area corresponding to
50 `ofs' in NAND flash to `addr'. This is limited to the 16 bytes of
51 data for one 512-byte page or 2 256-byte pages. There is no check
52 for bad blocks or ECC errors.
53
Stefan Roese856f0542006-10-28 15:55:52 +020054 nand write addr ofs|partition size
Scott Wood984e03c2008-06-12 13:13:23 -050055 Write `size' bytes from `addr' to `ofs' in NAND flash. Blocks that
56 are marked bad are skipped. If a page cannot be read because an
57 uncorrectable data error is found, the command stops with an error.
wdenk7a8e9bed2003-05-31 18:35:21 +000058
Scott Wood984e03c2008-06-12 13:13:23 -050059 As JFFS2 skips blocks similarly, this allows writing a JFFS2 image,
60 as long as the image is short enough to fit even after skipping the
61 bad blocks. Compact images, such as those produced by mkfs.jffs2
62 should work well, but loading an image copied from another flash is
63 going to be trouble if there are any bad blocks.
wdenk7a8e9bed2003-05-31 18:35:21 +000064
Ben Gardinerc9494862011-06-14 16:35:07 -040065 nand write.trimffs addr ofs|partition size
66 Enabled by the CONFIG_CMD_NAND_TRIMFFS macro. This command will write to
67 the NAND flash in a manner identical to the 'nand write' command
68 described above -- with the additional check that all pages at the end
69 of eraseblocks which contain only 0xff data will not be written to the
70 NAND flash. This behaviour is required when flashing UBI images
71 containing UBIFS volumes as per the UBI FAQ[1].
72
73 [1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_flasher_algo
74
Stefan Roese856f0542006-10-28 15:55:52 +020075 nand write.oob addr ofs|partition size
wdenk7a8e9bed2003-05-31 18:35:21 +000076 Write `size' bytes from `addr' to the out-of-band data area
77 corresponding to `ofs' in NAND flash. This is limited to the 16 bytes
78 of data for one 512-byte page or 2 256-byte pages. There is no check
79 for bad blocks.
80
Scott Wood418396e2012-03-02 14:01:57 -060081 nand read.raw addr ofs|partition [count]
82 nand write.raw addr ofs|partition [count]
83 Read or write one or more pages at "ofs" in NAND flash, from or to
84 "addr" in memory. This is a raw access, so ECC is avoided and the
85 OOB area is transferred as well. If count is absent, it is assumed
86 to be one page. As with .yaffs2 accesses, the data is formatted as
87 a packed sequence of "data, oob, data, oob, ..." -- no alignment of
88 individual pages is maintained.
Marek Vasutfb3659a2011-09-23 15:43:10 +020089
wdenk7a8e9bed2003-05-31 18:35:21 +000090Configuration Options:
91
Jon Loeligerb5501f72007-07-09 19:10:03 -050092 CONFIG_CMD_NAND
93 Enables NAND support and commmands.
wdenk7a8e9bed2003-05-31 18:35:21 +000094
Benoît Thébaudeau3287f6d2012-11-16 20:20:54 +010095 CONFIG_CMD_NAND_TORTURE
96 Enables the torture command (see description of this command below).
97
wdenk7a8e9bed2003-05-31 18:35:21 +000098 CONFIG_MTD_NAND_ECC_JFFS2
99 Define this if you want the Error Correction Code information in
100 the out-of-band data to be formatted to match the JFFS2 file system.
101 CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for
102 someone to implement.
103
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200104 CONFIG_SYS_MAX_NAND_DEVICE
wdenk7a8e9bed2003-05-31 18:35:21 +0000105 The maximum number of NAND devices you want to support.
106
Scott Wood99067b02009-04-01 15:33:24 -0500107 CONFIG_SYS_NAND_MAX_CHIPS
108 The maximum number of NAND chips per device to be supported.
wdenk7a8e9bed2003-05-31 18:35:21 +0000109
Scott Wood578931b2012-01-12 19:07:23 -0600110 CONFIG_SYS_NAND_SELF_INIT
111 Traditionally, glue code in drivers/mtd/nand/nand.c has driven
112 the initialization process -- it provides the mtd and nand
113 structs, calls a board init function for a specific device,
114 calls nand_scan(), and registers with mtd.
115
116 This arrangement does not provide drivers with the flexibility to
117 run code between nand_scan_ident() and nand_scan_tail(), or other
118 deviations from the "normal" flow.
119
120 If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c
121 will make one call to board_nand_init(), with no arguments. That
122 function is responsible for calling a driver init function for
123 each NAND device on the board, that performs all initialization
124 tasks except setting mtd->name, and registering with the rest of
125 U-Boot. Those last tasks are accomplished by calling nand_register()
126 on the new mtd device.
127
128 Example of new init to be added to the end of an existing driver
129 init:
130
131 /*
132 * devnum is the device number to be used in nand commands
133 * and in mtd->name. Must be less than
134 * CONFIG_SYS_NAND_MAX_DEVICE.
135 */
136 mtd = &nand_info[devnum];
137
138 /* chip is struct nand_chip, and is now provided by the driver. */
139 mtd->priv = &chip;
140
141 /*
142 * Fill in appropriate values if this driver uses these fields,
143 * or uses the standard read_byte/write_buf/etc. functions from
144 * nand_base.c that use these fields.
145 */
146 chip.IO_ADDR_R = ...;
147 chip.IO_ADDR_W = ...;
148
149 if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL))
150 error out
151
152 /*
153 * Insert here any code you wish to run after the chip has been
154 * identified, but before any other I/O is done.
155 */
156
157 if (nand_scan_tail(mtd))
158 error out
159
160 if (nand_register(devnum))
161 error out
162
163 In addition to providing more flexibility to the driver, it reduces
164 the difference between a U-Boot driver and its Linux counterpart.
165 nand_init() is now reduced to calling board_nand_init() once, and
166 printing a size summary. This should also make it easier to
167 transition to delayed NAND initialization.
168
169 Please convert your driver even if you don't need the extra
170 flexibility, so that one day we can eliminate the old mechanism.
171
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100172NOTE:
173=====
174
Scott Wood99067b02009-04-01 15:33:24 -0500175The current NAND implementation is based on what is in recent
Scott Woodbe33b042009-04-01 15:02:13 -0500176Linux kernels. The old legacy implementation has been removed.
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100177
Scott Wood99067b02009-04-01 15:33:24 -0500178If you have board code which used CONFIG_NAND_LEGACY, you'll need
179to convert to the current NAND interface for it to continue to work.
Wolfgang Denk4e3ccd22006-03-06 11:25:22 +0100180
Scott Wood99067b02009-04-01 15:33:24 -0500181The Disk On Chip driver is currently broken and has been for some time.
182There is a driver in drivers/mtd/nand, taken from Linux, that works with
183the current NAND system but has not yet been adapted to the u-boot
184environment.
Stefan Roese2255b2d2006-10-10 12:36:02 +0200185
Stefan Roese2255b2d2006-10-10 12:36:02 +0200186Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006
187
188JFFS2 related commands:
189
190 implement "nand erase clean" and old "nand erase"
191 using both the new code which is able to skip bad blocks
192 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob.
193
Stefan Roese2255b2d2006-10-10 12:36:02 +0200194Miscellaneous and testing commands:
195 "markbad [offset]"
196 create an artificial bad block (for testing bad block handling)
197
198 "scrub [offset length]"
199 like "erase" but don't skip bad block. Instead erase them.
200 DANGEROUS!!! Factory set bad blocks will be lost. Use only
201 to remove artificial bad blocks created with the "markbad" command.
202
Benoît Thébaudeau3287f6d2012-11-16 20:20:54 +0100203 "torture offset"
204 Torture block to determine if it is still reliable.
205 Enabled by the CONFIG_CMD_NAND_TORTURE configuration option.
206 This command returns 0 if the block is still reliable, else 1.
207 If the block is detected as unreliable, it is up to the user to decide to
208 mark this block as bad.
209 The analyzed block is put through 3 erase / write cycles (or less if the block
210 is detected as unreliable earlier).
211 This command can be used in scripts, e.g. together with the markbad command to
212 automate retries and handling of possibly newly detected bad blocks if the
213 nand write command fails.
214 It can also be used manually by users having seen some NAND errors in logs to
215 search the root cause of these errors.
216 The underlying nand_torture() function is also useful for code willing to
217 automate actions following a nand->write() error. This would e.g. be required
218 in order to program or update safely firmware to NAND, especially for the UBI
219 part of such firmware.
220
Stefan Roese2255b2d2006-10-10 12:36:02 +0200221
222NAND locking command (for chips with active LOCKPRE pin)
223
224 "nand lock"
225 set NAND chip to lock state (all pages locked)
226
227 "nand lock tight"
228 set NAND chip to lock tight state (software can't change locking anymore)
229
230 "nand lock status"
231 displays current locking status of all pages
232
233 "nand unlock [offset] [size]"
234 unlock consecutive area (can be called multiple times for different areas)
235
Joe Hershbergereee623a2012-08-22 16:49:42 -0500236 "nand unlock.allexcept [offset] [size]"
237 unlock all except specified consecutive area
Stefan Roese2255b2d2006-10-10 12:36:02 +0200238
239I have tested the code with board containing 128MiB NAND large page chips
240and 32MiB small page chips.