Commit Graph

15 Commits

Author SHA1 Message Date
David Woodhouse
d1da4e50e5 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	drivers/mtd/Kconfig

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-04-27 19:16:19 +01:00
Artem B. Bityutskiy
801c135ce7 UBI: Unsorted Block Images
UBI (Latin: "where?") manages multiple logical volumes on a single
flash device, specifically supporting NAND flash devices. UBI provides
a flexible partitioning concept which still allows for wear-levelling
across the whole flash device.

In a sense, UBI may be compared to the Logical Volume Manager
(LVM). Whereas LVM maps logical sector numbers to physical HDD sector
numbers, UBI maps logical eraseblocks to physical eraseblocks.

More information may be found at
http://www.linux-mtd.infradead.org/doc/ubi.html

Partitioning/Re-partitioning

  An UBI volume occupies a certain number of erase blocks. This is
  limited by a configured maximum volume size, which could also be
  viewed as the partition size. Each individual UBI volume's size can
  be changed independently of the other UBI volumes, provided that the
  sum of all volume sizes doesn't exceed a certain limit.

  UBI supports dynamic volumes and static volumes. Static volumes are
  read-only and their contents are protected by CRC check sums.

Bad eraseblocks handling

  UBI transparently handles bad eraseblocks. When a physical
  eraseblock becomes bad, it is substituted by a good physical
  eraseblock, and the user does not even notice this.

Scrubbing

  On a NAND flash bit flips can occur on any write operation,
  sometimes also on read. If bit flips persist on the device, at first
  they can still be corrected by ECC, but once they accumulate,
  correction will become impossible. Thus it is best to actively scrub
  the affected eraseblock, by first copying it to a free eraseblock
  and then erasing the original. The UBI layer performs this type of
  scrubbing under the covers, transparently to the UBI volume users.

Erase Counts

  UBI maintains an erase count header per eraseblock. This frees
  higher-level layers (like file systems) from doing this and allows
  for centralized erase count management instead. The erase counts are
  used by the wear-levelling algorithm in the UBI layer. The algorithm
  itself is exchangeable.

Booting from NAND

  For booting directly from NAND flash the hardware must at least be
  capable of fetching and executing a small portion of the NAND
  flash. Some NAND flash controllers have this kind of support. They
  usually limit the window to a few kilobytes in erase block 0. This
  "initial program loader" (IPL) must then contain sufficient logic to
  load and execute the next boot phase.

  Due to bad eraseblocks, which may be randomly scattered over the
  flash device, it is problematic to store the "secondary program
  loader" (SPL) statically. Also, due to bit-flips it may become
  corrupted over time. UBI allows to solve this problem gracefully by
  storing the SPL in a small static UBI volume.

UBI volumes vs. static partitions

  UBI volumes are still very similar to static MTD partitions:

    * both consist of eraseblocks (logical eraseblocks in case of UBI
      volumes, and physical eraseblocks in case of static partitions;
    * both support three basic operations - read, write, erase.

  But UBI volumes have the following advantages over traditional
  static MTD partitions:

    * there are no eraseblock wear-leveling constraints in case of UBI
      volumes, so the user should not care about this;
    * there are no bit-flips and bad eraseblocks in case of UBI volumes.

  So, UBI volumes may be considered as flash devices with relaxed
  restrictions.

Where can it be found?

  Documentation, kernel code and applications can be found in the MTD
  gits.

What are the applications for?

  The applications help to create binary flash images for two purposes: pfi
  files (partial flash images) for in-system update of UBI volumes, and plain
  binary images, with or without OOB data in case of NAND, for a manufacturing
  step. Furthermore some tools are/and will be created that allow flash content
  analysis after a system has crashed..

Who did UBI?

  The original ideas, where UBI is based on, were developed by Andreas
  Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and some others
  were involved too. The implementation of the kernel layer was done by Artem
  B. Bityutskiy. The user-space applications and tools were written by Oliver
  Lohmann with contributions from Frank Haverkamp, Andreas Arnez, and Artem.
  Joern Engel contributed a patch which modifies JFFS2 so that it can be run on
  a UBI volume. Thomas Gleixner did modifications to the NAND layer. Alexander
  Schmidt made some testing work as well as core functionality improvements.

Signed-off-by: Artem B. Bityutskiy <dedekind@linutronix.de>
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
2007-04-27 14:23:33 +03:00
Jan Engelhardt
ec98c681a5 Use menuconfig objects: MTD
Use menuconfigs instead of menus, so the whole menu can be disabled at once
instead of going through all options.

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-04-19 16:21:41 -05:00
Josh Boyer
f6a7ecb18d [MTD] add MTD_BLKDEVS Kconfig option
Add a MTD_BLKDEVS Kconfig option to cleanup the makefile a bit

Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>
2006-11-29 16:58:15 +02:00
Adrian Bunk
1ef93a0f66 [MTD] SSFDC must depend on BLOCK
This patch fixes the following compile error with
CONFIG_SSFDC=m, CONFIG_BLOCK=n:

<--  snip  -->

...
  CC [M]  drivers/mtd/mtd_blkdevs.o
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:40: warning: ‘struct request’ declared inside parameter list
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:40: warning: its scope is only this definition or declaration, which is probably not what you want
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c: In function ‘do_blktrans_request’:
/home/bunk/linux/kernel-2.6/git/linux-2.6/drivers/mtd/mtd_blkdevs.c:45: error: dereferencing pointer to incomplete type
...
make[3]: *** [drivers/mtd/mtd_blkdevs.o] Error 1

<--  snip  -->

Bug report by Jesper Juhl.

This patch also removes a pointless "default n" from the SSFDC option.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-10-09 07:25:28 +01:00
David Howells
9361401eb7 [PATCH] BLOCK: Make it possible to disable the block layer [try #6]
Make it possible to disable the block layer.  Not all embedded devices require
it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
the block layer to be present.

This patch does the following:

 (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
     support.

 (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
     an item that uses the block layer.  This includes:

     (*) Block I/O tracing.

     (*) Disk partition code.

     (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.

     (*) The SCSI layer.  As far as I can tell, even SCSI chardevs use the
     	 block layer to do scheduling.  Some drivers that use SCSI facilities -
     	 such as USB storage - end up disabled indirectly from this.

     (*) Various block-based device drivers, such as IDE and the old CDROM
     	 drivers.

     (*) MTD blockdev handling and FTL.

     (*) JFFS - which uses set_bdev_super(), something it could avoid doing by
     	 taking a leaf out of JFFS2's book.

 (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
     linux/elevator.h contingent on CONFIG_BLOCK being set.  sector_div() is,
     however, still used in places, and so is still available.

 (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
     parts of linux/fs.h.

 (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.

 (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.

 (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
     is not enabled.

 (*) fs/no-block.c is created to hold out-of-line stubs and things that are
     required when CONFIG_BLOCK is not set:

     (*) Default blockdev file operations (to give error ENODEV on opening).

 (*) Makes some /proc changes:

     (*) /proc/devices does not list any blockdevs.

     (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.

 (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.

 (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
     given command other than Q_SYNC or if a special device is specified.

 (*) In init/do_mounts.c, no reference is made to the blockdev routines if
     CONFIG_BLOCK is not defined.  This does not prohibit NFS roots or JFFS2.

 (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
     error ENOSYS by way of cond_syscall if so).

 (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
     CONFIG_BLOCK is not set, since they can't then happen.

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2006-09-30 20:52:31 +02:00
David Woodhouse
892e4fba1c [MTD] Fix dependencies with CONFIG_MTD=m
CMDLINEPARTS shouldn't be selectable, and neither should SSFDC, which
can be a tristate anyway.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-09-23 10:24:36 +01:00
Claudio Lanconelli
51197abf29 [MTD] Add SSFDC (SmartMedia) read-only translation layer
Signed-off-by: Claudio Lanconelli <lanconelli.claudio@eptar.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-09-22 11:01:37 +01:00
Linus Torvalds
2a2ed2db35 Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild
* git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild: (40 commits)
  kbuild: trivial fixes in Makefile
  kbuild: adding symbols in Kconfig and defconfig to TAGS
  kbuild: replace abort() with exit(1)
  kbuild: support for %.symtypes files
  kbuild: fix silentoldconfig recursion
  kbuild: add option for stripping modules while installing them
  kbuild: kill some false positives from modpost
  kbuild: export-symbol usage report generator
  kbuild: fix make -rR breakage
  kbuild: append -dirty for updated but uncommited changes
  kbuild: append git revision for all untagged commits
  kbuild: fix module.symvers parsing in modpost
  kbuild: ignore make's built-in rules & variables
  kbuild: bugfix with initramfs
  kbuild: modpost build fix
  kbuild: check license compatibility when building modules
  kbuild: export-type enhancement to modpost.c
  kbuild: add dependency on kernel.release to the package targets
  kbuild: `make kernelrelease' speedup
  kconfig: KCONFIG_OVERWRITECONFIG
  ...
2006-06-26 11:05:15 -07:00
Roman Zippel
e55a3e8aed kconfig: remove leading whitespace in menu prompts
This removes all the leading whitespace kconfig now warns about.

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2006-06-09 16:28:07 +02:00
Egry Gábor
4992a9e888 Trivial typo fixes in Kconfig files (MTD).
Signed-off-by: Egry Gábor <gaboregry@t-online.hu>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-05-12 17:35:02 +01:00
Thomas Gleixner
97894cda57 [MTD] core: Clean up trailing white spaces
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2005-11-07 13:37:38 +01:00
Kyungmin Park
cd5f6346bc [MTD] Add initial support for OneNAND flash chips
OneNAND is a new flash technology from Samsung with integrated SRAM
buffers and logic interface.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2005-11-06 21:17:24 +01:00
Sean Young
e27a9960af [MTD] Add Resident Flash Disk (RFD) support
This type of flash translation layer (FTL) is used by the Embedded BIOS
by General Software. It is known as the Resident Flash Disk (RFD), see:

http://www.gensw.com/pages/prod/bios/rfd.htm

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2005-11-06 20:08:54 +01:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00