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_MTD_NAND_ECC_JFFS2 112 Define this if you want the Error Correction Code information in 113 the out-of-band data to be formatted to match the JFFS2 file system. 114 CONFIG_MTD_NAND_ECC_YAFFS would be another useful choice for 115 someone to implement. 116 117 CONFIG_SYS_MAX_NAND_DEVICE 118 The maximum number of NAND devices you want to support. 119 120 CONFIG_SYS_NAND_MAX_CHIPS 121 The maximum number of NAND chips per device to be supported. 122 123 CONFIG_SYS_NAND_SELF_INIT 124 Traditionally, glue code in drivers/mtd/nand/nand.c has driven 125 the initialization process -- it provides the mtd and nand 126 structs, calls a board init function for a specific device, 127 calls nand_scan(), and registers with mtd. 128 129 This arrangement does not provide drivers with the flexibility to 130 run code between nand_scan_ident() and nand_scan_tail(), or other 131 deviations from the "normal" flow. 132 133 If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c 134 will make one call to board_nand_init(), with no arguments. That 135 function is responsible for calling a driver init function for 136 each NAND device on the board, that performs all initialization 137 tasks except setting mtd->name, and registering with the rest of 138 U-Boot. Those last tasks are accomplished by calling nand_register() 139 on the new mtd device. 140 141 Example of new init to be added to the end of an existing driver 142 init: 143 144 /* 145 * devnum is the device number to be used in nand commands 146 * and in mtd->name. Must be less than 147 * CONFIG_SYS_NAND_MAX_DEVICE. 148 */ 149 mtd = &nand_info[devnum]; 150 151 /* chip is struct nand_chip, and is now provided by the driver. */ 152 mtd->priv = &chip; 153 154 /* 155 * Fill in appropriate values if this driver uses these fields, 156 * or uses the standard read_byte/write_buf/etc. functions from 157 * nand_base.c that use these fields. 158 */ 159 chip.IO_ADDR_R = ...; 160 chip.IO_ADDR_W = ...; 161 162 if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL)) 163 error out 164 165 /* 166 * Insert here any code you wish to run after the chip has been 167 * identified, but before any other I/O is done. 168 */ 169 170 if (nand_scan_tail(mtd)) 171 error out 172 173 if (nand_register(devnum)) 174 error out 175 176 In addition to providing more flexibility to the driver, it reduces 177 the difference between a U-Boot driver and its Linux counterpart. 178 nand_init() is now reduced to calling board_nand_init() once, and 179 printing a size summary. This should also make it easier to 180 transition to delayed NAND initialization. 181 182 Please convert your driver even if you don't need the extra 183 flexibility, so that one day we can eliminate the old mechanism. 184 185NOTE: 186===== 187 188The current NAND implementation is based on what is in recent 189Linux kernels. The old legacy implementation has been removed. 190 191If you have board code which used CONFIG_NAND_LEGACY, you'll need 192to convert to the current NAND interface for it to continue to work. 193 194The Disk On Chip driver is currently broken and has been for some time. 195There is a driver in drivers/mtd/nand, taken from Linux, that works with 196the current NAND system but has not yet been adapted to the u-boot 197environment. 198 199Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 200 201JFFS2 related commands: 202 203 implement "nand erase clean" and old "nand erase" 204 using both the new code which is able to skip bad blocks 205 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob. 206 207Miscellaneous and testing commands: 208 "markbad [offset]" 209 create an artificial bad block (for testing bad block handling) 210 211 "scrub [offset length]" 212 like "erase" but don't skip bad block. Instead erase them. 213 DANGEROUS!!! Factory set bad blocks will be lost. Use only 214 to remove artificial bad blocks created with the "markbad" command. 215 216 217NAND locking command (for chips with active LOCKPRE pin) 218 219 "nand lock" 220 set NAND chip to lock state (all pages locked) 221 222 "nand lock tight" 223 set NAND chip to lock tight state (software can't change locking anymore) 224 225 "nand lock status" 226 displays current locking status of all pages 227 228 "nand unlock [offset] [size]" 229 unlock consecutive area (can be called multiple times for different areas) 230 231 "nand unlock.allexcept [offset] [size]" 232 unlock all except specified consecutive area 233 234I have tested the code with board containing 128MiB NAND large page chips 235and 32MiB small page chips. 236