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
  48           If unsure, say N.
  49
  50 config YAFFS_DOES_ECC
  51         bool "Lets Yaffs do its own ECC"
  52         depends on YAFFS_FS && YAFFS_YAFFS1 && !YAFFS_9BYTE_TAGS
  53         default n
  54         help
  55           This enables Yaffs to use its own ECC functions instead of using
  56           the ones from the generic MTD-NAND driver.
  57
  58           If unsure, say N.
  59
  60 config YAFFS_ECC_WRONG_ORDER
  61         bool "Use the same ecc byte order as Steven Hill's nand_ecc.c"
  62         depends on YAFFS_FS && YAFFS_DOES_ECC && !YAFFS_9BYTE_TAGS
  63         default n
  64         help
  65           This makes yaffs_ecc.c use the same ecc byte order as Steven
  66           Hill's nand_ecc.c. If not set, then you get the same ecc byte
  67           order as SmartMedia.
  68
  69           If unsure, say N.
  70
  71 config YAFFS_YAFFS2
  72         bool "2048 byte (or larger) / page devices"
  73         depends on YAFFS_FS
  74         default y
  75         help
  76           Enable YAFFS2 support -- yaffs for >= 2K bytes per page devices
  77
  78           If unsure, say Y.
  79
  80 config YAFFS_AUTO_YAFFS2
  81         bool "Autoselect yaffs2 format"
  82         depends on YAFFS_YAFFS2
  83         default y
  84         help
  85           Without this, you need to explicitely use yaffs2 as the file
  86           system type. With this, you can say "yaffs" and yaffs or yaffs2
  87           will be used depending on the device page size (yaffs on
  88           512-byte page devices, yaffs2 on 2K page devices).
  89
  90           If unsure, say Y.
  91
  92 config YAFFS_DISABLE_LAZY_LOAD
  93         bool "Disable lazy loading"
  94         depends on YAFFS_YAFFS2
  95         default n
  96         help
  97           "Lazy loading" defers loading file details until they are
  98           required. This saves mount time, but makes the first look-up
  99           a bit longer.
 100
 101           Lazy loading will only happen if enabled by this option being 'n'
 102           and if the appropriate tags are available, else yaffs2 will
 103           automatically fall back to immediate loading and do the right
 104           thing.
 105
 106           Lazy laoding will be required by checkpointing.
 107
 108           Setting this to 'y' will disable lazy loading.
 109
 110           If unsure, say N.
 111
 112 config YAFFS_CHECKPOINT_RESERVED_BLOCKS
 113         int "Reserved blocks for checkpointing"
 114         depends on YAFFS_YAFFS2
 115         default 10
 116         help
 117           Give the number of Blocks to reserve for checkpointing.
 118           Checkpointing saves the state at unmount so that mounting is
 119           much faster as a scan of all the flash to regenerate this state
 120           is not needed.  These Blocks are reserved per partition, so if
 121           you have very small partitions the default (10) may be a mess
 122           for you.  You can set this value to 0, but that does not mean
 123           checkpointing is disabled at all. There only won't be any
 124           specially reserved blocks for checkpointing, so if there is
 125           enough free space on the filesystem, it will be used for
 126           checkpointing.
 127
 128           If unsure, leave at default (10), but don't wonder if there are
 129           always 2MB used on your large page device partition (10 x 2k
 130           pagesize). When using small partitions or when being very small
 131           on space, you probably want to set this to zero.
 132
 133 config YAFFS_DISABLE_WIDE_TNODES
 134         bool "Turn off wide tnodes"
 135         depends on YAFFS_FS
 136         default n
 137         help
 138           Wide tnodes are only used for NAND arrays >=32MB for 512-byte
 139           page devices and >=128MB for 2k page devices. They use slightly
 140           more RAM but are faster since they eliminate chunk group
 141           searching.
 142
 143           Setting this to 'y' will force tnode width to 16 bits and save
 144           memory but make large arrays slower.
 145
 146           If unsure, say N.
 147
 148 config YAFFS_ALWAYS_CHECK_CHUNK_ERASED
 149         bool "Force chunk erase check"
 150         depends on YAFFS_FS
 151         default n
 152         help
 153           Normally YAFFS only checks chunks before writing until an erased
 154           chunk is found. This helps to detect any partially written
 155           chunks that might have happened due to power loss.
 156
 157           Enabling this forces on the test that chunks are erased in flash
 158           before writing to them. This takes more time but is potentially
 159           a bit more secure.
 160
 161           Suggest setting Y during development and ironing out driver
 162           issues etc. Suggest setting to N if you want faster writing.
 163
 164           If unsure, say Y.
 165
 166 config YAFFS_SHORT_NAMES_IN_RAM
 167         bool "Cache short names in RAM"
 168         depends on YAFFS_FS
 169         default y
 170         help
 171           If this config is set, then short names are stored with the
 172           yaffs_Object.  This costs an extra 16 bytes of RAM per object,
 173           but makes look-ups faster.
 174
 175           If unsure, say Y.