doc/README.JFFS2

   1 JFFS2 options and usage.
   2 -----------------------
   3
   4 JFFS2 in U-Boot is a read only implementation of the file system in
   5 Linux with the same name. To use JFFS2 define CONFIG_CMD_JFFS2.
   6
   7 The module adds three new commands.
   8 fsload  - load binary file from a file system image
   9 fsinfo  - print information about file systems
  10 ls      - list files in a directory
  11 chpart  - change active partition
  12
  13 If you do now need the commands, you can enable the filesystem separately
  14 with CONFIG_FS_JFFS2 and call the jffs2 functions yourself.
  15
  16 If you boot from a partition which is mounted writable, and you
  17 update your boot environment by replacing single files on that
  18 partition, you should also define CONFIG_SYS_JFFS2_SORT_FRAGMENTS. Scanning
  19 the JFFS2 filesystem takes *much* longer with this feature, though.
  20 Sorting is done while inserting into the fragment list, which is
  21 more or less a bubble sort. That algorithm is known to be O(n^2),
  22 thus you should really consider if you can avoid it!
  23
  24
  25 There only one way for JFFS2 to find the disk. It uses the flash_info
  26 structure to find the start of a JFFS2 disk (called partition in the code)
  27 and you can change where the partition is with two defines.
  28
  29 CONFIG_SYS_JFFS2_FIRST_BANK
  30         defined the first flash bank to use
  31
  32 CONFIG_SYS_JFFS2_FIRST_SECTOR
  33         defines the first sector to use
  34 ---
  35
  36 TODO.
  37
  38         Remove the assumption that JFFS can dereference a pointer
  39         into the disk. The current code do not work with memory holes
  40         or hardware with a sliding window (PCMCIA).