fs/cramfs/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 config CRAMFS
   3         tristate "Compressed ROM file system support (cramfs)"
   4         select ZLIB_INFLATE
   5         help
   6           Saying Y here includes support for CramFs (Compressed ROM File
   7           System).  CramFs is designed to be a simple, small, and compressed
   8           file system for ROM based embedded systems.  CramFs is read-only,
   9           limited to 256MB file systems (with 16MB files), and doesn't support
  10           16/32 bits uid/gid, hard links and timestamps.
  11
  12           See <file:Documentation/filesystems/cramfs.txt> and
  13           <file:fs/cramfs/README> for further information.
  14
  15           To compile this as a module, choose M here: the module will be called
  16           cramfs.  Note that the root file system (the one containing the
  17           directory /) cannot be compiled as a module.
  18
  19           This filesystem is limited in capabilities and performance on
  20           purpose to remain small and low on RAM usage. It is most suitable
  21           for small embedded systems. If you have ample RAM to spare, you may
  22           consider a more capable compressed filesystem such as SquashFS
  23           which is much better in terms of performance and features.
  24
  25           If unsure, say N.
  26
  27 config CRAMFS_BLOCKDEV
  28         bool "Support CramFs image over a regular block device" if EXPERT
  29         depends on CRAMFS && BLOCK
  30         default y
  31         help
  32           This option allows the CramFs driver to load data from a regular
  33           block device such a disk partition or a ramdisk.
  34
  35 config CRAMFS_MTD
  36         bool "Support CramFs image directly mapped in physical memory"
  37         depends on CRAMFS && CRAMFS <= MTD
  38         default y if !CRAMFS_BLOCKDEV
  39         help
  40           This option allows the CramFs driver to load data directly from
  41           a linear adressed memory range (usually non volatile memory
  42           like flash) instead of going through the block device layer.
  43           This saves some memory since no intermediate buffering is
  44           necessary.
  45
  46           The location of the CramFs image is determined by a
  47           MTD device capable of direct memory mapping e.g. from
  48           the 'physmap' map driver or a resulting MTD partition.
  49           For example, this would mount the cramfs image stored in
  50           the MTD partition named "xip_fs" on the /mnt mountpoint:
  51
  52           mount -t cramfs mtd:xip_fs /mnt
  53
  54           If unsure, say N.