xref: /openbmc/linux/fs/cramfs/Kconfig (revision ba61bb17)
1config CRAMFS
2	tristate "Compressed ROM file system support (cramfs)"
3	select ZLIB_INFLATE
4	help
5	  Saying Y here includes support for CramFs (Compressed ROM File
6	  System).  CramFs is designed to be a simple, small, and compressed
7	  file system for ROM based embedded systems.  CramFs is read-only,
8	  limited to 256MB file systems (with 16MB files), and doesn't support
9	  16/32 bits uid/gid, hard links and timestamps.
10
11	  See <file:Documentation/filesystems/cramfs.txt> and
12	  <file:fs/cramfs/README> for further information.
13
14	  To compile this as a module, choose M here: the module will be called
15	  cramfs.  Note that the root file system (the one containing the
16	  directory /) cannot be compiled as a module.
17
18	  This filesystem is limited in capabilities and performance on
19	  purpose to remain small and low on RAM usage. It is most suitable
20	  for small embedded systems. If you have ample RAM to spare, you may
21	  consider a more capable compressed filesystem such as SquashFS
22	  which is much better in terms of performance and features.
23
24	  If unsure, say N.
25
26config CRAMFS_BLOCKDEV
27	bool "Support CramFs image over a regular block device" if EXPERT
28	depends on CRAMFS && BLOCK
29	default y
30	help
31	  This option allows the CramFs driver to load data from a regular
32	  block device such a disk partition or a ramdisk.
33
34config CRAMFS_MTD
35	bool "Support CramFs image directly mapped in physical memory"
36	depends on CRAMFS && CRAMFS <= MTD
37	default y if !CRAMFS_BLOCKDEV
38	help
39	  This option allows the CramFs driver to load data directly from
40	  a linear adressed memory range (usually non volatile memory
41	  like flash) instead of going through the block device layer.
42	  This saves some memory since no intermediate buffering is
43	  necessary.
44
45	  The location of the CramFs image is determined by a
46	  MTD device capable of direct memory mapping e.g. from
47	  the 'physmap' map driver or a resulting MTD partition.
48	  For example, this would mount the cramfs image stored in
49	  the MTD partition named "xip_fs" on the /mnt mountpoint:
50
51	  mount -t cramfs mtd:xip_fs /mnt
52
53	  If unsure, say N.
54