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Move this piece of code to sort-me-out/. See README.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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Fixed a problem when ECC was checked. The correction was not properly
done by subpage. Added more output for the moment to be able to figure
out more potential problems.
Added testcase: bin2nand2bin.sh and biterror inject program inject_biterror.pl
Interface
o ECC correction disabled by default. Switch to turn it
explicitly on. The user must specify what he wants to be done.
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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The extraction of data from blocks used for dynamic volumes was
totally broken. The data size was calculated wrong. This fix is not
perfect, the alignment is still ignored.
The parameter "header-size" is very misleading. It does not reflect
the vid hdr offset properly. I assume therefor that it only works for
the layout I am using where the vid hdr is at the _end_ of the 1st
NAND page (2048).
I added the generation of a textfile with information about the blocks
which are going into the internal graph representation.
Instead of a graph I think that a simple array will simplify the code
very much. The array must than be sorted properly to cope with older
and newer block-copies but that should not be a problem.
discussed the tool with my coleage Andreas Arnez and we found that it
might be a good idea to replace it even with a perl program for the
same purpose since that would offer the flexibility to change it on
the fly when needed. The tool is mainly used for crash analysis so it
could be an advantage to change it without needing a C-compiler.
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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We have no good testcases for this kind of tool yet. Adding a 1st
draft.
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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This patch fixes UBI tests and adds udev problems solution description.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
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Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
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The testscripts ensure the correct functionality of the UBI code on
my reference system.
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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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 in the UBI design documentation:
ubidesign.pdf. Which can be found here:
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 and also
some to JFFS2 to make it work.
Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
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