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.oob addr ofs|partition size 82 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 89 CONFIG_CMD_NAND 90 Enables NAND support and commmands. 91 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 98 CONFIG_SYS_MAX_NAND_DEVICE 99 The maximum number of NAND devices you want to support. 100 101 CONFIG_SYS_NAND_MAX_CHIPS 102 The maximum number of NAND chips per device to be supported. 103 104NOTE: 105===== 106 107The current NAND implementation is based on what is in recent 108Linux kernels. The old legacy implementation has been removed. 109 110If you have board code which used CONFIG_NAND_LEGACY, you'll need 111to convert to the current NAND interface for it to continue to work. 112 113The Disk On Chip driver is currently broken and has been for some time. 114There is a driver in drivers/mtd/nand, taken from Linux, that works with 115the current NAND system but has not yet been adapted to the u-boot 116environment. 117 118Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 119 120JFFS2 related commands: 121 122 implement "nand erase clean" and old "nand erase" 123 using both the new code which is able to skip bad blocks 124 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob. 125 126Miscellaneous and testing commands: 127 "markbad [offset]" 128 create an artificial bad block (for testing bad block handling) 129 130 "scrub [offset length]" 131 like "erase" but don't skip bad block. Instead erase them. 132 DANGEROUS!!! Factory set bad blocks will be lost. Use only 133 to remove artificial bad blocks created with the "markbad" command. 134 135 136NAND locking command (for chips with active LOCKPRE pin) 137 138 "nand lock" 139 set NAND chip to lock state (all pages locked) 140 141 "nand lock tight" 142 set NAND chip to lock tight state (software can't change locking anymore) 143 144 "nand lock status" 145 displays current locking status of all pages 146 147 "nand unlock [offset] [size]" 148 unlock consecutive area (can be called multiple times for different areas) 149 150 151I have tested the code with board containing 128MiB NAND large page chips 152and 32MiB small page chips. 153