LXR linux/fs/cramfs/Kconfig

   1# SPDX-License-Identifier: GPL-2.0-only
   2config 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.rst> 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
  27config 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
  35config 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.
  55