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1 | NAND FLASH commands and notes |
2 | ||
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3 | See NOTE below!!! |
4 | ||
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5 | # (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 | ||
26 | Commands: | |
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 | ||
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37 | 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. | |
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47 | |
48 | If `clean' is specified, a JFFS2-style clean marker is written to | |
856f0544 | 49 | each block after it is erased. |
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50 | |
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 | ||
856f0544 | 59 | nand read addr ofs|partition size |
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60 | Read `size' bytes from `ofs' in NAND flash to `addr'. If a page |
61 | cannot be read because it is marked bad or an uncorrectable data | |
8bde7f77 | 62 | error is found the command stops with an error. |
7a8e9bed | 63 | |
856f0544 | 64 | nand read.jffs2 addr ofs|partition size |
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65 | Like `read', but the data for blocks that are marked bad is read as |
66 | 0xff. This gives a readable JFFS2 image that can be processed by | |
67 | the JFFS2 commands such as ls and fsload. | |
68 | ||
856f0544 | 69 | nand read.oob addr ofs|partition size |
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70 | Read `size' bytes from the out-of-band data area corresponding to |
71 | `ofs' in NAND flash to `addr'. This is limited to the 16 bytes of | |
72 | data for one 512-byte page or 2 256-byte pages. There is no check | |
73 | for bad blocks or ECC errors. | |
74 | ||
856f0544 | 75 | nand write addr ofs|partition size |
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76 | Write `size' bytes from `addr' to `ofs' in NAND flash. If a page |
77 | cannot be written because it is marked bad or the write fails the | |
8bde7f77 | 78 | command stops with an error. |
7a8e9bed | 79 | |
856f0544 | 80 | nand write.jffs2 addr ofs|partition size |
7a8e9bed | 81 | Like `write', but blocks that are marked bad are skipped and the |
10c7382b | 82 | data is written to the next block instead. This allows writing |
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83 | a JFFS2 image, as long as the image is short enough to fit even |
84 | after skipping the bad blocks. Compact images, such as those | |
85 | produced by mkfs.jffs2 should work well, but loading an image copied | |
86 | from another flash is going to be trouble if there are any bad blocks. | |
87 | ||
856f0544 | 88 | nand write.oob addr ofs|partition size |
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89 | Write `size' bytes from `addr' to the out-of-band data area |
90 | corresponding to `ofs' in NAND flash. This is limited to the 16 bytes | |
91 | of data for one 512-byte page or 2 256-byte pages. There is no check | |
92 | for bad blocks. | |
93 | ||
94 | Configuration Options: | |
95 | ||
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96 | CONFIG_CMD_NAND |
97 | Enables NAND support and commmands. | |
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98 | |
99 | CONFIG_MTD_NAND_ECC_JFFS2 | |
100 | Define this if you want the Error Correction Code information in | |
101 | the out-of-band data to be formatted to match the JFFS2 file system. | |
102 | CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for | |
103 | someone to implement. | |
104 | ||
105 | CFG_MAX_NAND_DEVICE | |
106 | The maximum number of NAND devices you want to support. | |
107 | ||
108 | NAND Interface: | |
109 | ||
110 | #define NAND_WAIT_READY(nand) | |
111 | Wait until the NAND flash is ready. Typically this would be a | |
112 | loop waiting for the READY/BUSY line from the flash to indicate it | |
113 | it is ready. | |
114 | ||
115 | #define WRITE_NAND_COMMAND(d, adr) | |
116 | Write the command byte `d' to the flash at `adr' with the | |
117 | CLE (command latch enable) line true. If your board uses writes to | |
118 | different addresses to control CLE and ALE, you can modify `adr' | |
119 | to be the appropriate address here. If your board uses I/O registers | |
120 | to control them, it is probably better to let NAND_CTL_SETCLE() | |
121 | and company do it. | |
122 | ||
123 | #define WRITE_NAND_ADDRESS(d, adr) | |
124 | Write the address byte `d' to the flash at `adr' with the | |
125 | ALE (address latch enable) line true. If your board uses writes to | |
126 | different addresses to control CLE and ALE, you can modify `adr' | |
127 | to be the appropriate address here. If your board uses I/O registers | |
128 | to control them, it is probably better to let NAND_CTL_SETALE() | |
129 | and company do it. | |
130 | ||
131 | #define WRITE_NAND(d, adr) | |
132 | Write the data byte `d' to the flash at `adr' with the | |
133 | ALE and CLE lines false. If your board uses writes to | |
134 | different addresses to control CLE and ALE, you can modify `adr' | |
135 | to be the appropriate address here. If your board uses I/O registers | |
136 | to control them, it is probably better to let NAND_CTL_CLRALE() | |
137 | and company do it. | |
138 | ||
139 | #define READ_NAND(adr) | |
140 | Read a data byte from the flash at `adr' with the | |
141 | ALE and CLE lines false. If your board uses reads from | |
142 | different addresses to control CLE and ALE, you can modify `adr' | |
143 | to be the appropriate address here. If your board uses I/O registers | |
144 | to control them, it is probably better to let NAND_CTL_CLRALE() | |
145 | and company do it. | |
146 | ||
147 | #define NAND_DISABLE_CE(nand) | |
148 | Set CE (Chip Enable) low to enable the NAND flash. | |
149 | ||
150 | #define NAND_ENABLE_CE(nand) | |
151 | Set CE (Chip Enable) high to disable the NAND flash. | |
152 | ||
153 | #define NAND_CTL_CLRALE(nandptr) | |
154 | Set ALE (address latch enable) low. If ALE control is handled by | |
155 | WRITE_NAND_ADDRESS() this can be empty. | |
156 | ||
157 | #define NAND_CTL_SETALE(nandptr) | |
158 | Set ALE (address latch enable) high. If ALE control is handled by | |
159 | WRITE_NAND_ADDRESS() this can be empty. | |
160 | ||
161 | #define NAND_CTL_CLRCLE(nandptr) | |
162 | Set CLE (command latch enable) low. If CLE control is handled by | |
163 | WRITE_NAND_ADDRESS() this can be empty. | |
164 | ||
165 | #define NAND_CTL_SETCLE(nandptr) | |
166 | Set CLE (command latch enable) high. If CLE control is handled by | |
167 | WRITE_NAND_ADDRESS() this can be empty. | |
8bde7f77 | 168 | |
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169 | More Definitions: |
170 | ||
171 | These definitions are needed in the board configuration for now, but | |
172 | may really belong in a header file. | |
173 | TODO: Figure which ones are truly configuration settings and rename | |
8bde7f77 | 174 | them to CFG_NAND_... and move the rest somewhere appropriate. |
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175 | |
176 | #define SECTORSIZE 512 | |
177 | #define ADDR_COLUMN 1 | |
178 | #define ADDR_PAGE 2 | |
179 | #define ADDR_COLUMN_PAGE 3 | |
180 | #define NAND_ChipID_UNKNOWN 0x00 | |
181 | #define NAND_MAX_FLOORS 1 | |
182 | #define NAND_MAX_CHIPS 1 | |
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183 | |
184 | ||
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185 | NOTE: |
186 | ===== | |
187 | ||
188 | We now use a complete rewrite of the NAND code based on what is in | |
189 | 2.6.12 Linux kernel. | |
190 | ||
191 | The old NAND handling code has been re-factored and is now confined | |
192 | to only board-specific files and - unfortunately - to the DoC code | |
193 | (see below). A new configuration variable has been introduced: | |
194 | CFG_NAND_LEGACY, which has to be defined in the board config file if | |
323bfa8f | 195 | that board uses legacy code. |
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196 | |
197 | The necessary changes have been made to all affected boards, and no | |
198 | build breakage has been introduced, except for NETTA and NETTA_ISDN | |
199 | targets from MAKEALL. This is due to the fact that these two boards | |
200 | use JFFS, which has been adopted to use the new NAND, and at the same | |
201 | time use NAND in legacy mode. The breakage will disappear when the | |
202 | board-specific code is changed to the new NAND. | |
203 | ||
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204 | As mentioned above, the legacy code is still used by the DoC subsystem. |
205 | The consequence of this is that the legacy NAND can't be removed from | |
206 | the tree until the DoC is ported to use the new NAND support (or boards | |
4e3ccd26 | 207 | with DoC will break). |
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208 | |
209 | ||
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210 | Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 |
211 | ||
212 | JFFS2 related commands: | |
213 | ||
214 | implement "nand erase clean" and old "nand erase" | |
215 | using both the new code which is able to skip bad blocks | |
216 | "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob. | |
217 | ||
218 | "nand write.jffs2" | |
219 | like "nand write" but skip found bad eraseblocks | |
220 | ||
221 | "nand read.jffs2" | |
222 | like "nand read" but skip found bad eraseblocks | |
223 | ||
224 | Miscellaneous and testing commands: | |
225 | "markbad [offset]" | |
226 | create an artificial bad block (for testing bad block handling) | |
227 | ||
228 | "scrub [offset length]" | |
229 | like "erase" but don't skip bad block. Instead erase them. | |
230 | DANGEROUS!!! Factory set bad blocks will be lost. Use only | |
231 | to remove artificial bad blocks created with the "markbad" command. | |
232 | ||
233 | ||
234 | NAND locking command (for chips with active LOCKPRE pin) | |
235 | ||
236 | "nand lock" | |
237 | set NAND chip to lock state (all pages locked) | |
238 | ||
239 | "nand lock tight" | |
240 | set NAND chip to lock tight state (software can't change locking anymore) | |
241 | ||
242 | "nand lock status" | |
243 | displays current locking status of all pages | |
244 | ||
245 | "nand unlock [offset] [size]" | |
246 | unlock consecutive area (can be called multiple times for different areas) | |
247 | ||
248 | ||
249 | I have tested the code with board containing 128MiB NAND large page chips | |
250 | and 32MiB small page chips. |