target/linux/generic-2.6/files-2.6.25/fs/yaffs2/Kconfig

   1 #
   2 # YAFFS file system configurations
   3 #
   4
   5 config YAFFS_FS
   6         tristate "YAFFS2 file system support"
   7         default n
   8         depends on MTD
   9         select YAFFS_YAFFS1
  10         select YAFFS_YAFFS2
  11         help
  12           YAFFS2, or Yet Another Flash Filing System, is a filing system
  13           optimised for NAND Flash chips.
  14
  15           To compile the YAFFS2 file system support as a module, choose M
  16           here: the module will be called yaffs2.
  17
  18           If unsure, say N.
  19
  20           Further information on YAFFS2 is available at
  21           <http://www.aleph1.co.uk/yaffs/>.
  22
  23 config YAFFS_YAFFS1
  24         bool "512 byte / page devices"
  25         depends on YAFFS_FS
  26         default y
  27         help
  28           Enable YAFFS1 support -- yaffs for 512 byte / page devices
  29
  30           Not needed for 2K-page devices.
  31
  32           If unsure, say Y.
  33
  34 config YAFFS_9BYTE_TAGS
  35         bool "Use older-style on-NAND data format with pageStatus byte"
  36         depends on YAFFS_YAFFS1
  37         default n
  38         help
  39
  40           Older-style on-NAND data format has a "pageStatus" byte to record
  41           chunk/page state.  This byte is zero when the page is discarded.
  42           Choose this option if you have existing on-NAND data using this
  43           format that you need to continue to support.  New data written
  44           also uses the older-style format.  Note: Use of this option
  45           generally requires that MTD's oob layout be adjusted to use the
  46           older-style format.  See notes on tags formats and MTD versions
  47           in yaffs_mtdif1.c.
  48
  49           If unsure, say N.
  50
  51 config YAFFS_DOES_ECC
  52         bool "Lets Yaffs do its own ECC"
  53         depends on YAFFS_FS && YAFFS_YAFFS1 && !YAFFS_9BYTE_TAGS
  54         default n
  55         help
  56           This enables Yaffs to use its own ECC functions instead of using
  57           the ones from the generic MTD-NAND driver.
  58
  59           If unsure, say N.
  60
  61 config YAFFS_ECC_WRONG_ORDER
  62         bool "Use the same ecc byte order as Steven Hill's nand_ecc.c"
  63         depends on YAFFS_FS && YAFFS_DOES_ECC && !YAFFS_9BYTE_TAGS
  64         default n
  65         help
  66           This makes yaffs_ecc.c use the same ecc byte order as Steven
  67           Hill's nand_ecc.c. If not set, then you get the same ecc byte
  68           order as SmartMedia.
  69
  70           If unsure, say N.
  71
  72 config YAFFS_YAFFS2
  73         bool "2048 byte (or larger) / page devices"
  74         depends on YAFFS_FS
  75         default y
  76         help
  77           Enable YAFFS2 support -- yaffs for >= 2K bytes per page devices
  78
  79           If unsure, say Y.
  80
  81 config YAFFS_AUTO_YAFFS2
  82         bool "Autoselect yaffs2 format"
  83         depends on YAFFS_YAFFS2
  84         default y
  85         help
  86           Without this, you need to explicitely use yaffs2 as the file
  87           system type. With this, you can say "yaffs" and yaffs or yaffs2
  88           will be used depending on the device page size (yaffs on
  89           512-byte page devices, yaffs2 on 2K page devices).
  90
  91           If unsure, say Y.
  92
  93 config YAFFS_DISABLE_LAZY_LOAD
  94         bool "Disable lazy loading"
  95         depends on YAFFS_YAFFS2
  96         default n
  97         help
  98           "Lazy loading" defers loading file details until they are
  99           required. This saves mount time, but makes the first look-up
 100           a bit longer.
 101
 102           Lazy loading will only happen if enabled by this option being 'n'
 103           and if the appropriate tags are available, else yaffs2 will
 104           automatically fall back to immediate loading and do the right
 105           thing.
 106
 107           Lazy laoding will be required by checkpointing.
 108
 109           Setting this to 'y' will disable lazy loading.
 110
 111           If unsure, say N.
 112
 113
 114 config YAFFS_DISABLE_WIDE_TNODES
 115         bool "Turn off wide tnodes"
 116         depends on YAFFS_FS
 117         default n
 118         help
 119           Wide tnodes are only used for NAND arrays >=32MB for 512-byte
 120           page devices and >=128MB for 2k page devices. They use slightly
 121           more RAM but are faster since they eliminate chunk group
 122           searching.
 123
 124           Setting this to 'y' will force tnode width to 16 bits and save
 125           memory but make large arrays slower.
 126
 127           If unsure, say N.
 128
 129 config YAFFS_ALWAYS_CHECK_CHUNK_ERASED
 130         bool "Force chunk erase check"
 131         depends on YAFFS_FS
 132         default n
 133         help
 134           Normally YAFFS only checks chunks before writing until an erased
 135           chunk is found. This helps to detect any partially written
 136           chunks that might have happened due to power loss.
 137
 138           Enabling this forces on the test that chunks are erased in flash
 139           before writing to them. This takes more time but is potentially
 140           a bit more secure.
 141
 142           Suggest setting Y during development and ironing out driver
 143           issues etc. Suggest setting to N if you want faster writing.
 144
 145           If unsure, say Y.
 146
 147 config YAFFS_SHORT_NAMES_IN_RAM
 148         bool "Cache short names in RAM"
 149         depends on YAFFS_FS
 150         default y
 151         help
 152           If this config is set, then short names are stored with the
 153           yaffs_Object.  This costs an extra 16 bytes of RAM per object,
 154           but makes look-ups faster.
 155
 156           If unsure, say Y.