Commit graph

19 commits

Author SHA1 Message Date
Artem Bityutskiy
4415626732 UBI: amend commentaries WRT dtype
Richard removed the "dtype" hint, but few commentaries were left and this patch
removes them. I've also added a better description about the "dtype" field in
the ubi-user.h for people who may ever wonder what was that dtype thing about.

This patch also adds an important note that it is better to use value "3" for
the "dtype" field.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-05-20 20:25:59 +03:00
Richard Weinberger
a65a0eb6d1 UBI: remove data type hint from ubi-user.h
This finally removes the data type hint from the UBI ABI.
>From now on the "dtype" field will be ignored and must not used
anymore.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
2012-05-20 20:25:59 +03:00
Artem Bityutskiy
feddbb34eb UBI: fix minor stylistic issues
Fix checkpatch.pl errors and warnings:

* space before tab
* line over 80 characters
* include linux/ioctl.h instead of asm/ioctl.h

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:41 +03:00
Artem Bityutskiy
3627924acf UBI: use __packed instead of __attribute__((packed))
There was an attempt to standartize various "__attribute__" and
other macros in order to have potentially portable and more
consistent code, see commit 82ddcb0405.

Note, that commit refers Rober Love's blog post, but the URL
is broken, the valid URL is:
http://blog.rlove.org/2005/10/with-little-help-from-your-compiler.html

Moreover, nowadays checkpatch.pl warns about using
__attribute__((packed)):

"WARNING: __packed is preferred over __attribute__((packed))"

It is not a big deal for UBI to use __packed, so let's do it.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:41 +03:00
Artem Bityutskiy
e8e088de30 UBI: cleanup comments around volume properties
Cleanup and improve commentaries around the "set volume properties" ioctl,
make a simple indentation fix as well.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:40 +03:00
Artem Bityutskiy
6748482f41 UBI: re-name set volume properties ioctl
Rename the ioctl which sets volume properties from 'UBI_IOCSETPROP' to
'UBI_IOCSETVOLPROP' to reflect the fact that this ioctl is about volume
properties, not device properties. This is also consistent with the
other volume ioctl name - 'UBI_IOCVOLUP'.

The main motivation for the re-name, however, is that we are going
to introduce the per-UBI device "set properties" ioctl, so we need
good and logical naming.

At the same time, re-name the "set volume properties request" data
structure from 'struct ubi_set_prop_req' to
'struct ubi_set_vol_prop_req'.

And re-name 'UBI_PROP_DIRECT_WRITE' to 'UBI_VOL_PROP_DIRECT_WRITE'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2011-04-14 11:34:40 +03:00
David Woodhouse
a1452a3771 mtd: Update copyright notices
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2010-08-08 20:58:20 +01:00
Arnd Bergmann
ccef7ab534 make MTD headers use strict integer types
The MTD headers traditionally use stdint types rather than
the kernel integer types. This converts them to do the
same as all the others.

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-26 18:14:17 +01:00
Sidney Amani
766fb95ba0 UBI: allow direct user-space I/O
Introduce a new ioctl UBI_IOCSETPROP to set properties
on a volume. Also add the first property:
UBI_PROP_DIRECT_WRITE, this property is used to set the
ability to use direct writes in userspace

Signed-off-by: Sidney Amani <seed@uffs.org>
Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-27 16:54:41 +02:00
Artem Bityutskiy
f7fc6f3f33 UBI: improve ioctl commentaries
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary
a27ce8f55d UBI: add ioctl for is_mapped operation
This patch adds ioctl to check if an LEB is mapped or not (as a
debugging option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary
c3da23be16 UBI: add ioctl for unmap operation
This patch adds ioctl for the LEB unmap operation (as a debugging
option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +02:00
Corentin Chary
141e6ebd1b UBI: add ioctl for map operation
This patch adds ioctl for the LEB map operation (as a debugging
option so far).

[Re-named ioctl to make it look the same as the other one and made
 some minor stylistic changes. Artem Bityutskiy.]

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2009-01-18 14:02:08 +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
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
866136827b UBI: introduce atomic LEB change ioctl
We have to be able to change individual LEBs for utilities like
ubifsck, ubifstune. For example, ubifsck has to be able to fix
errors on the media, ubifstune has to be able to change the
the superblock, hence this ioctl.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-01-25 16:41:25 +02:00
Artem Bityutskiy
9b79cc0f84 UBI: introduce attach ioctls
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:17 +02:00
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