1NAND FLASH commands and notes 2 3See NOTE below!!! 4 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 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 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. 47 48 If `clean' is specified, a JFFS2-style clean marker is written to 49 each block after it is erased. 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 59 nand read addr ofs|partition size 60 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. 63 64 nand read.oob addr ofs|partition size 65 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 70 nand write addr ofs|partition size 71 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. 74 75 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. 80 81 nand write.trimffs addr ofs|partition size 82 Enabled by the CONFIG_CMD_NAND_TRIMFFS macro. This command will write to 83 the NAND flash in a manner identical to the 'nand write' command 84 described above -- with the additional check that all pages at the end 85 of eraseblocks which contain only 0xff data will not be written to the 86 NAND flash. This behaviour is required when flashing UBI images 87 containing UBIFS volumes as per the UBI FAQ[1]. 88 89 [1] http://www.linux-mtd.infradead.org/doc/ubi.html#L_flasher_algo 90 91 nand write.oob addr ofs|partition size 92 Write `size' bytes from `addr' to the out-of-band data area 93 corresponding to `ofs' in NAND flash. This is limited to the 16 bytes 94 of data for one 512-byte page or 2 256-byte pages. There is no check 95 for bad blocks. 96 97 nand read.raw addr ofs|partition [count] 98 nand write.raw addr ofs|partition [count] 99 Read or write one or more pages at "ofs" in NAND flash, from or to 100 "addr" in memory. This is a raw access, so ECC is avoided and the 101 OOB area is transferred as well. If count is absent, it is assumed 102 to be one page. As with .yaffs2 accesses, the data is formatted as 103 a packed sequence of "data, oob, data, oob, ..." -- no alignment of 104 individual pages is maintained. 105 106Configuration Options: 107 108 CONFIG_CMD_NAND 109 Enables NAND support and commmands. 110 111 CONFIG_CMD_NAND_TORTURE 112 Enables the torture command (see description of this command below). 113 114 CONFIG_MTD_NAND_ECC_JFFS2 115 Define this if you want the Error Correction Code information in 116 the out-of-band data to be formatted to match the JFFS2 file system. 117 CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for 118 someone to implement. 119 120 CONFIG_SYS_MAX_NAND_DEVICE 121 The maximum number of NAND devices you want to support. 122 123 CONFIG_SYS_NAND_MAX_CHIPS 124 The maximum number of NAND chips per device to be supported. 125 126 CONFIG_SYS_NAND_SELF_INIT 127 Traditionally, glue code in drivers/mtd/nand/nand.c has driven 128 the initialization process -- it provides the mtd and nand 129 structs, calls a board init function for a specific device, 130 calls nand_scan(), and registers with mtd. 131 132 This arrangement does not provide drivers with the flexibility to 133 run code between nand_scan_ident() and nand_scan_tail(), or other 134 deviations from the "normal" flow. 135 136 If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c 137 will make one call to board_nand_init(), with no arguments. That 138 function is responsible for calling a driver init function for 139 each NAND device on the board, that performs all initialization 140 tasks except setting mtd->name, and registering with the rest of 141 U-Boot. Those last tasks are accomplished by calling nand_register() 142 on the new mtd device. 143 144 Example of new init to be added to the end of an existing driver 145 init: 146 147 /* 148 * devnum is the device number to be used in nand commands 149 * and in mtd->name. Must be less than 150 * CONFIG_SYS_NAND_MAX_DEVICE. 151 */ 152 mtd = &nand_info[devnum]; 153 154 /* chip is struct nand_chip, and is now provided by the driver. */ 155 mtd->priv = &chip; 156 157 /* 158 * Fill in appropriate values if this driver uses these fields, 159 * or uses the standard read_byte/write_buf/etc. functions from 160 * nand_base.c that use these fields. 161 */ 162 chip.IO_ADDR_R = ...; 163 chip.IO_ADDR_W = ...; 164 165 if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL)) 166 error out 167 168 /* 169 * Insert here any code you wish to run after the chip has been 170 * identified, but before any other I/O is done. 171 */ 172 173 if (nand_scan_tail(mtd)) 174 error out 175 176 if (nand_register(devnum)) 177 error out 178 179 In addition to providing more flexibility to the driver, it reduces 180 the difference between a U-Boot driver and its Linux counterpart. 181 nand_init() is now reduced to calling board_nand_init() once, and 182 printing a size summary. This should also make it easier to 183 transition to delayed NAND initialization. 184 185 Please convert your driver even if you don't need the extra 186 flexibility, so that one day we can eliminate the old mechanism. 187 188NOTE: 189===== 190 191The current NAND implementation is based on what is in recent 192Linux kernels. The old legacy implementation has been removed. 193 194If you have board code which used CONFIG_NAND_LEGACY, you'll need 195to convert to the current NAND interface for it to continue to work. 196 197The Disk On Chip driver is currently broken and has been for some time. 198There is a driver in drivers/mtd/nand, taken from Linux, that works with 199the current NAND system but has not yet been adapted to the u-boot 200environment. 201 202Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 203 204JFFS2 related commands: 205 206 implement "nand erase clean" and old "nand erase" 207 using both the new code which is able to skip bad blocks 208 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob. 209 210Miscellaneous and testing commands: 211 "markbad [offset]" 212 create an artificial bad block (for testing bad block handling) 213 214 "scrub [offset length]" 215 like "erase" but don't skip bad block. Instead erase them. 216 DANGEROUS!!! Factory set bad blocks will be lost. Use only 217 to remove artificial bad blocks created with the "markbad" command. 218 219 "torture offset" 220 Torture block to determine if it is still reliable. 221 Enabled by the CONFIG_CMD_NAND_TORTURE configuration option. 222 This command returns 0 if the block is still reliable, else 1. 223 If the block is detected as unreliable, it is up to the user to decide to 224 mark this block as bad. 225 The analyzed block is put through 3 erase / write cycles (or less if the block 226 is detected as unreliable earlier). 227 This command can be used in scripts, e.g. together with the markbad command to 228 automate retries and handling of possibly newly detected bad blocks if the 229 nand write command fails. 230 It can also be used manually by users having seen some NAND errors in logs to 231 search the root cause of these errors. 232 The underlying nand_torture() function is also useful for code willing to 233 automate actions following a nand->write() error. This would e.g. be required 234 in order to program or update safely firmware to NAND, especially for the UBI 235 part of such firmware. 236 237 238NAND locking command (for chips with active LOCKPRE pin) 239 240 "nand lock" 241 set NAND chip to lock state (all pages locked) 242 243 "nand lock tight" 244 set NAND chip to lock tight state (software can't change locking anymore) 245 246 "nand lock status" 247 displays current locking status of all pages 248 249 "nand unlock [offset] [size]" 250 unlock consecutive area (can be called multiple times for different areas) 251 252 "nand unlock.allexcept [offset] [size]" 253 unlock all except specified consecutive area 254 255I have tested the code with board containing 128MiB NAND large page chips 256and 32MiB small page chips. 257