History log of /include/mtd/ubi-user.h
Revision Date Author Comments (<<< Hide modified files) (Show modified files >>>)
feddbb34ebd75e9b6bf573b852079e327a88c07a 28-Mar-2011 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
3627924acf70a9a26587712e4888ee7144489678 28-Mar-2011 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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 82ddcb040570411fc2d421d96b3e69711c670328.

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>
/include/mtd/ubi-user.h
e8e088de305d7cc00b2c8b2a857ceb62d5fa68d3 15-Mar-2011 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
6748482f4153fc0e095aa3dc831d5edac5656a80 15-Mar-2011 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
a1452a3771c4eb85bd779790b040efdc36f4274e 08-Aug-2010 David Woodhouse <David.Woodhouse@intel.com> mtd: Update copyright notices

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
/include/mtd/ubi-user.h
ccef7ab534347e2e1e1ef398d2ec987d37e519f3 26-Feb-2009 Arnd Bergmann <arnd@arndb.de> 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>
/include/mtd/ubi-user.h
766fb95ba06e1bbf531d30dc05e21b2d4a0e8dd2 27-Jan-2009 Sidney Amani <seed@uffs.org> 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>
/include/mtd/ubi-user.h
f7fc6f3f33703e3365c0ef9d4bf322b88cc9dae7 07-Jan-2009 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> UBI: improve ioctl commentaries

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
/include/mtd/ubi-user.h
a27ce8f55dd5fddf0b8ea179cce8f399c13dc94f 05-Jan-2009 Corentin Chary <corentincj@iksaif.net> 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>
/include/mtd/ubi-user.h
c3da23be1673be4e738aea235604b4e6cb259655 05-Jan-2009 Corentin Chary <corentincj@iksaif.net> 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>
/include/mtd/ubi-user.h
141e6ebd1b1759bd5cebf092b7216b6f1c7b4c4f 05-Jan-2009 Corentin Chary <corentincj@iksaif.net> 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>
/include/mtd/ubi-user.h
025dfdafe77f20b3890981a394774baab7b9c827 16-Oct-2008 Frederik Schwarzer <schwarzerf@gmail.com> 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>
/include/mtd/ubi-user.h
9c9ec147709e63e4e8ac6a037c6bb50688ff8e9c 18-Jul-2008 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
f40ac9cdf6991287f19bdafe9b0752ee40137908 13-Jul-2008 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
866136827b9a71c39dcb06d23ce523f719eab74b 24-Jan-2008 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 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>
/include/mtd/ubi-user.h
9b79cc0f84edecceb04b806b9014fcec1306c34d 18-Dec-2007 Artem Bityutskiy <Artem.Bityutskiy@nokia.com> UBI: introduce attach ioctls

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
/include/mtd/ubi-user.h
801c135ce73d5df1caf3eca35b66a10824ae0707 26-Jun-2006 Artem B. Bityutskiy <dedekind@linutronix.de> 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>
/include/mtd/ubi-user.h