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 98 Read page from `ofs' in NAND flash to `addr'. This reads the raw page, 99 so ECC is avoided and the OOB area is read as well. 100 101 nand write.raw addr ofs|partition 102 Write page from `addr' to `ofs' in NAND flash. This writes the raw page, 103 so ECC is avoided and the OOB area is written as well, making the whole 104 page written as-is. 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 123NOTE: 124===== 125 126The current NAND implementation is based on what is in recent 127Linux kernels. The old legacy implementation has been removed. 128 129If you have board code which used CONFIG_NAND_LEGACY, you'll need 130to convert to the current NAND interface for it to continue to work. 131 132The Disk On Chip driver is currently broken and has been for some time. 133There is a driver in drivers/mtd/nand, taken from Linux, that works with 134the current NAND system but has not yet been adapted to the u-boot 135environment. 136 137Additional improvements to the NAND subsystem by Guido Classen, 10-10-2006 138 139JFFS2 related commands: 140 141 implement "nand erase clean" and old "nand erase" 142 using both the new code which is able to skip bad blocks 143 "nand erase clean" additionally writes JFFS2-cleanmarkers in the oob. 144 145Miscellaneous and testing commands: 146 "markbad [offset]" 147 create an artificial bad block (for testing bad block handling) 148 149 "scrub [offset length]" 150 like "erase" but don't skip bad block. Instead erase them. 151 DANGEROUS!!! Factory set bad blocks will be lost. Use only 152 to remove artificial bad blocks created with the "markbad" command. 153 154 155NAND locking command (for chips with active LOCKPRE pin) 156 157 "nand lock" 158 set NAND chip to lock state (all pages locked) 159 160 "nand lock tight" 161 set NAND chip to lock tight state (software can't change locking anymore) 162 163 "nand lock status" 164 displays current locking status of all pages 165 166 "nand unlock [offset] [size]" 167 unlock consecutive area (can be called multiple times for different areas) 168 169 170I have tested the code with board containing 128MiB NAND large page chips 171and 32MiB small page chips. 172