Commit Graph

40 Commits

Author SHA1 Message Date
Richard Weinberger 1f4f43475f UBI: use own macros for the layout volume
This is a minor nicification: UBI_LAYOUT_VOLUME_TYPE and
UBI_LAYOUT_VOLUME_ALIGN are currently defined but not used -
use them.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
2012-01-15 15:08:55 +02:00
Richard Weinberger 6bdccffe8c UBI: make vid_hdr non-static
Remove 'static' modifier from the 'vid_hdr' local variable. I do not know
how it slipped in, but this is a bug and will break UBI if someone attaches
2 UBI volumes at the same time.

Artem: amended teh commit message, added -stable.

Signed-off-by: Richard Weinberger <rw@linutronix.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Cc: stable@kernel.org
2012-01-10 10:59:01 +02:00
Brian Norris d57f40544a mtd: utilize `mtd_is_*()' functions
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
2011-09-21 09:19:06 +03:00
Artem Bityutskiy 4788b60a5f UBI: remove dead code
Thanks to new gcc 4.6 for issuing the following warning:

drivers/mtd/ubi/vtbl.c: In function ‘create_vtbl’:
drivers/mtd/ubi/vtbl.c:311:33: warning: variable ‘old_seb’ set but not used [-Wunused-but-set-variable]

This patch removes some dead code and fixes the warning.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-07 09:15:55 +03:00
Artem Bityutskiy 2a734bb8d5 UBI: use debugfs for the extra checks knobs
This patch introduces debugfs support to UBI. All the UBI stuff is kept in the
"ubi" debugfs directory, which contains per-UBI device "ubi/ubiX"
sub-directories, containing debugging files. This file also creates
"ubi/ubiX/chk_gen" and "ubi/ubiX/chk_io" knobs for switching general and I/O
extra checks on and off. And it removes the 'debug_chks' UBI module parameters.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-06-01 11:21:47 +03:00
Linus Torvalds fd57ed0219 Merge branch 'linux-next' of git://git.infradead.org/ubi-2.6
* 'linux-next' of git://git.infradead.org/ubi-2.6:
  UBI: make tests modes dynamic
  UBI: make self-checks dynamic
  UBI: make debugging messages dynamic
  UBI: remove UBI_IO_DEBUG macro
  UBI: kill debugging buffer
  UBI: allocate erase checking buffer on demand
  UBI: allocate write checking buffer on demand
  UBI: always re-read in case of read failures
  UBI: cleanup comments about corrupted PEBs
  UBI: add slab cache for ubi_scan_leb objects
  UBI: use raw mtd read function in debugging code
  UBI: try to reveal buggy MTD drivers
  UBI: add a commentary about allocating VID header buffer on stack
  UBI: cleanup LEB start calculations
  UBI: fix NOR erase preparation quirk
2011-03-18 10:50:02 -07:00
Artem Bityutskiy 92d124f531 UBI: make self-checks dynamic
This patch adds a possibility to dynamically switch UBI self-checks
on and off, instead of toggling them compile-time from the configuration
menu. This is much more flexible, and consistent with UBIFS, and this
also simplifies UBI Kconfig menu and the code.

This patch introduces two levels of self-checks - general, which
includes all self-checks which are relatively fast, and I/O, which
includes write-verify checks and erase-verify checks, which are
relatively slow and involve flash I/O.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-03-16 13:50:16 +02:00
Joe Perches 309b5e4e41 mtd: use vzalloc
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-12-03 16:27:29 +00:00
Artem Bityutskiy 5fc01ab693 UBI: preserve corrupted PEBs
Currently UBI erases all corrupted eraseblocks, irrespectively of the nature
of corruption: corruption due to power cuts and non-power cut corruption.
The former case is OK, but the latter is not, because UBI may destroy
potentially important data.

With this patch, during scanning, when UBI hits a PEB with corrupted VID
header, it checks whether this PEB contains only 0xFF data. If yes, it is
safe to erase this PEB and it is put to the 'erase' list. If not, this may
be important data and it is better to avoid erasing this PEB. Instead,
UBI puts it to the corr list and moves out of the pool of available PEB.
IOW, UBI preserves this PEB.

Such corrupted PEB lessen the amount of available PEBs. So the more of them
we accumulate, the less PEBs are available. The maximum amount of non-power
cut corrupted PEBs is 8.

This patch is a response to UBIFS problem where reporter
(Matthew L. Creech <mlcreech@gmail.com>) observes that UBIFS index points
to an unmapped LEB. The theory is that corresponding PEB somehow got
corrupted and UBI wiped it. This patch (actually a series of patches)
tries to make sure such PEBs are preserved - this would make it is easier
to analyze the corruption.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2010-10-19 17:19:57 +03:00
Artem Bityutskiy 0525dac9fd UBI: do not put eraseblocks to the corrupted list unnecessarily
Currently UBI maintains 2 lists of PEBs during scanning:
1. 'erase' list - PEBs which have no corruptions but should be erased
2. 'corr' list - PEBs which have some corruptions and should be erased

But we do not really need 2 lists for PEBs which should be erased after
scanning is done - this is redundant. So this patch makes sure all PEBs
which are corrupted are moved to the head of the 'erase' list. We add
them to the head to make sure they are erased first and we get rid of
corruption ASAP.

However, we do not remove the 'corr' list and realted functions, because
the plan is to use this list for other purposes. Namely, we plan to
put eraseblocks with corruption which does not look like it was caused
by unclean power cut. Then we'll preserve thes PEBs in order to avoid
killing potentially valuable user data.

This patch also amends PEBs accounting, because it was closely tight to
the 'erase'/'corr' lists separation.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2010-10-19 17:19:57 +03:00
Shinya Kuribayashi be436f6238 UBI: misc comment fixes
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2010-05-07 08:33:32 +03:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Peter Horton ff99879328 UBI: initialise update marker
The in kernel copy of a volume's update marker is not initialised from the
volume table. This means that volumes where an update was unfinnished will
not be treated as "forbidden to use". This is basically that the update
functionality was broken.

Signed-off-by: Peter Horton <zero@colonel-panic.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Cc: stable@kernel.org
2010-01-12 13:19:08 +02:00
Frederik Schwarzer 025dfdafe7 trivial: fix then -> than typos in comments and documentation
- (better, more, bigger ...) then -> (...) than

Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-01-06 11:28:06 +01:00
Deepak Saxena 762a9f291b UBI: print reserved_peb when it is too large
This patch makes debugging a missconfigured UBI a bit easier
by providing the needed information in the boot log.

Signed-off-by: Deepak Saxena <dsaxena@laptop.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-10-09 16:19:04 +03:00
Artem Bityutskiy 9869cd801c UBI: remove pre-sqnum images support
Before UBI got into mainline, there was a slight flash format
change - we did not have sequence number support, then added it.

We have carried full support of those ancient images till this
moment. Now the support is removed, well, not fully removed.

Now UBI will support only _clean_ old images, which were cleanly
detached last time (just before kernel upgrade). This is most
likely the case.

But we will not support unclean ancient images. Surprisingly,
this allows us to remove a big chunk of legacy code.

And the same should be true for downgrading: clean images should
downgrade fine, but unclean ones will not.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:36:09 +03:00
Artem Bityutskiy ebaaf1af3e UBI: fix kernel-doc errors and warnings
No functional changes, just tweak comments to make kernel-doc
work fine and stop complaining.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:36:09 +03:00
Artem Bityutskiy 9c9ec14770 UBI: fix checkpatch.pl errors and warnings
Just out or curiousity ran checkpatch.pl for whole UBI,
and discovered there are quite a few of stylistic issues.
Fix them.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:36:09 +03:00
Artem Bityutskiy f40ac9cdf6 UBI: implement multiple volumes rename
Quite useful ioctl which allows to make atomic system upgrades.
The idea belongs to Richard Titmuss <richard_titmuss@logitech.com>

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:34:46 +03:00
Artem Bityutskiy c8566350a3 UBI: fix and re-work debugging stuff
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:34:45 +03:00
Kyungmin Park cadb40ccc1 UBI: avoid unnecessary division operations
UBI already checks that @min io size is the power of 2 at io_init.
It is save to use bit operations then.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:32:54 +03:00
Artem Bityutskiy beeea63603 UBI: add a comment
It is not clear why we schedule PEB for scrubbing in case of
-EBADMSG. Elaborate.

Requested-by: Kyungmin Park <kmpark@infradead.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:32:54 +03:00
Artem Bityutskiy 979c9296bd UBI: print error code
Print error code if checking failed which is very useful
to identify problems.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:32:54 +03:00
Adrian Bunk f7f0283776 UBI: mtd/ubi/vtbl.c: fix memory leak
This patch fixes a memory leak introduced by commit
4ccf8cffa9 and spotted by the Coverity
checker.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-03-04 11:03:09 +02:00
Artem Bityutskiy 6dc4a8717f UBI: do not flush queue on each vtbl change
This is just not necessary. We re-write whole layout copy, so
the old contents cannot show up again sice scan process will
drop it.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-02-01 13:48:49 +02:00
Artem Bityutskiy 91f2d53cd7 UBI: add layout volume information
Add more information about layout volume to make userspace tools
use the macros instead of constants. Also rename UBI_LAYOUT_VOL_ID
to make it consistent with other macros.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:25 +02:00
Artem Bityutskiy 4ccf8cffa9 UBI: add auto-resize feature
The problem: NAND flashes have different amount of initial bad physical
eraseblocks (marked as bad by the manufacturer). For example, for 256MiB
Samsung OneNAND flash there might be from 0 to 40 bad initial eraseblocks,
which is about 2%. When UBI is used as the base system, one needs to know
the exact amount of good physical eraseblocks, because this number is
needed to create the UBI image which is put to the devices during
production. But this number is not know, which forces us to use the
minimum number of good physical eraseblocks. And UBI additionally
reserves some percentage of physical eraseblocks for bad block handling
(default is 1%), so we have 1-3% of PEBs reserved at the end, depending
on the amount of initial bad PEBs. But it is desired to always have
1% (or more, depending on the configuration).

Solution: this patch adds an "auto-resize" flag to the volume table.
The volume which has the "auto-resize" flag will automatically be re-sized
(enlarged) on the first UBI initialization. UBI clears the flag when
the volume is re-sized. Only one volume may have the "auto-resize" flag.

So, the production UBI image may have one volume with "auto-resize"
flag set, and its size is automatically adjusted on the first boot
of the device.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:24 +02:00
Artem Bityutskiy 16f557ecbf UBI: fix comment
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:16 +02:00
Artem Bityutskiy d05c77a816 UBI: introduce volume refcounting
Add ref_count field to UBI volumes and remove weired "vol->removed"
field. This way things are better understandable and we do not have
to do whold show_attr operation under spinlock.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:16 +02:00
Artem Bityutskiy cae0a77125 UBI: tweak volumes locking
Transform vtbl_mutex to volumes_mutex - this just makes code
easier to understand.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:15 +02:00
Artem Bityutskiy 89b96b6929 UBI: improve internal interfaces
Pass volume description object to the EBA function which makes
more sense, and EBA function do not have to find the volume
description object by volume ID.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:15 +02:00
Artem Bityutskiy e88d6e10e5 UBI: do not use vmalloc on I/O path
Similar reason as in case of the previous patch: it causes
deadlocks if a filesystem with writeback support works on top
of UBI. So pre-allocate needed buffers when attaching MTD device.
We also need mutexes to protect the buffers, but they do not
cause much contantion because they are used in recovery, torture,
and WL copy routines, which are called seldom.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14 13:10:21 +03:00
Artem Bityutskiy 33818bbb84 UBI: allocate memory with GFP_NOFS
Use GFP_NOFS flag when allocating memory on I/O path, because otherwise
we may deadlock the filesystem which works on top of us. We observed
the deadlocks with UBIFS. Example:

VFS->FS lock a lock->UBI->kmalloc()->VFS writeback->FS locks the same
lock again.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14 13:10:20 +03:00
Vinit Agnihotri d08c3b78b8 UBI: fix overflow bug
I was experiencing overflows in multiplications for
volume->used_bytes in vmt.c & vtbl.c, while creating & resizing large volumes.

vol->used_bytes is long long however its 2 operands vol->used_ebs &
vol->usable_leb_size
are int. So their multiplication for larger values causes integer overflows.
Typecasting them solves the problem.

My machine & flash details:

64Bit dual-core AMD opteron, 1 GB RAM, linux 2.6.18.3.
mtd size = 6GB, volume size= 5GB, peb_size = 4MB.

heres patch which does the fix.

Signed-off-by: Vinit Agnihotri <vinit.agnihotri@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:58:12 +03:00
Artem Bityutskiy 94784d9164 UBI: bugfix in error path
When volume creation fails, we have to set ubi->volumes[vol_id]
back to NULL.

This patch also tweaks some debugging stuff.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:55:55 +03:00
Christoph Hellwig 3261ebd7d4 UBI: kill homegrown endian macros
Kill UBI's homegrown endianess handling and replace it with
the standard kernel endianess handling.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:53:49 +03:00
Artem Bityutskiy 92ad8f3750 UBI: use vmalloc for large buffers
UBI allocates temporary buffers of PEB size, which may be 256KiB.
Use vmalloc instead of kmalloc for such big temporary buffers.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:53:08 +03:00
Artem Bityutskiy 78d87c95b8 UBI: fix error path in create_vtbl()
There were several bugs in volume table creation error path. Thanks to
Satyam Sharma <satyam.sharma@gmail.com> and Florin Malita <fmalita@gmail.com>
for finding and analysing them: http://lkml.org/lkml/2007/5/3/274

This patch makes ubi_scan_add_to_list() static and renames it to
add_to_list(), just because it is not needed outside scan.c anymore.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:52:32 +03:00
Florin Malita c4e90ec013 UBI: fix dereference after kfree
Coverity (CID 1614) spotted new_seb being dereferenced after kfree() in
create_vtbl's write_error path.

Signed-off-by: Florin Malita <fmalita@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18 16:52:22 +03:00
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