Commit Graph

164 Commits

Author SHA1 Message Date
Kay Sievers
475b44c199 mtd: struct device - replace bus_id with dev_name(), dev_set_name()
CC: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-01-06 10:44:38 -08:00
Eric W. Biederman
467622ef2a [MTD] [NOR] Fix cfi_send_gen_cmd handling of x16 devices in x8 mode (v4)
For "unlock" cycles to 16bit devices in 8bit compatibility mode we need
to use the byte addresses 0xaaa and 0x555. These effectively match
the word address 0x555 and 0x2aa, except the latter has its low bit set.

Most chips don't care about the value of the 'A-1' pin in x8 mode,
but some -- like the ST M29W320D -- do. So we need to be careful to
set it where appropriate.

cfi_send_gen_cmd is only ever passed addresses where the low byte
is 0x00, 0x55 or 0xaa. Of those, only addresses ending 0xaa are
affected by this patch, by masking in the extra low bit when the device
is known to be in compatibility mode.

[dwmw2: Do it only when (cmd_ofs & 0xff) == 0xaa]
v4: Fix  stupid typo in cfi_build_cmd_addr that failed to compile
    I'm writing this patch way to late at night.
v3: Bring all of the work back into cfi_build_cmd_addr
    including calling of map_bankwidth(map) and cfi_interleave(cfi)
    So every caller doesn't need to.
v2: Only modified the address if we our device_type is larger than our
    bus width.

Cc: stable@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-11-05 14:40:25 +01:00
Linus Torvalds
2be508d847 Merge git://git.infradead.org/mtd-2.6
* git://git.infradead.org/mtd-2.6: (69 commits)
  Revert "[MTD] m25p80.c code cleanup"
  [MTD] [NAND] GPIO driver depends on ARM... for now.
  [MTD] [NAND] sh_flctl: fix compile error
  [MTD] [NOR] AT49BV6416 has swapped erase regions
  [MTD] [NAND] GPIO NAND flash driver
  [MTD] cmdlineparts documentation change - explain where mtd-id comes from
  [MTD] cfi_cmdset_0002.c: Add Macronix CFI V1.0 TopBottom detection
  [MTD] [NAND] Fix compilation warnings in drivers/mtd/nand/cs553x_nand.c
  [JFFS2] Write buffer offset adjustment for NOR-ECC (Sibley) flash
  [MTD] mtdoops: Fix a bug where block may not be erased
  [MTD] mtdoops: Add a magic number to logged kernel oops
  [MTD] mtdoops: Fix an off by one error
  [JFFS2] Correct parameter names of jffs2_compress() in comments
  [MTD] [NAND] sh_flctl: add support for Renesas SuperH FLCTL
  [MTD] [NAND] Bug on atmel_nand HW ECC : OOB info not correctly written
  [MTD] [MAPS] Remove unused variable after ROM API cleanup.
  [MTD] m25p80.c extended jedec support (v2)
  [MTD] remove unused mtd parameter in of_mtd_parse_partitions()
  [MTD] [NAND] remove dead Kconfig associated with !CONFIG_PPC_MERGE
  [MTD] [NAND] driver extension to support NAND on TQM85xx modules
  ...
2008-10-20 09:03:12 -07:00
Mike Rapoport
aaf7ea2000 [MTD] [NAND] GPIO NAND flash driver
The patch adds support for NAND flashes connected to GPIOs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-10-18 12:48:42 +01:00
Yoshihiro Shimoda
6028aa01f7 [MTD] [NAND] sh_flctl: add support for Renesas SuperH FLCTL
Several Renesas SuperH CPU has FLCTL. The FLCTL support NAND Flash.
This driver support SH7723.

Signed-off-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-10-14 13:33:05 +01:00
Sebastian Andrzej Siewior
69fd3a8d09 [MTD] remove unused mtd parameter in of_mtd_parse_partitions()
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-10-13 15:01:42 +01:00
David Woodhouse
eae9acd13a Support 'discard sectors' operation in translation layer support core
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:01 +02:00
Alexey Korolev
17c1d2be28 [MTD] [NAND] Fix missing kernel-doc
[Reported by Randy Dunlap]

Signed-off-by: Alexey Korolev <akorolev@infradead.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-20 22:35:40 +01:00
Adrian Hunter
bb0eb217c9 [MTD] Define and use MTD_FAIL_ADDR_UNKNOWN instead of 0xffffffff
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-12 11:02:15 +01:00
David Woodhouse
c314dfdc35 [MTD] [NOR] Rename and export new cfi_qry_*() functions
They need to be exported, so let's give them less generic-sounding names
while we're at it.

Original export patch, along with the suggestion about the nomenclature,
from Stephen Rothwell.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-07 11:55:07 +01:00
Anders Grafström
e93cafe45f [MTD] [NOR] cfi_cmdset_0001: Timeouts for erase, write and unlock operations
Timeouts are currently given by the typical operation time times 8.
It works in the general well-behaved case but not when an erase block is
failing. For erase operations, it seems that a failing erase block will
keep the device state machine in erasing state until the vendor
specified maximum timeout period has passed. By this time the driver
would have long since timed out, left erasing state and attempted
further operations which all fail. This patch implements timeouts using
values from the CFI Query structure when available.
The patch also sets a longer timeout for locking operations. The current
value used for locking/unlocking given by 1000000/HZ microseconds is too
short for devices like J3 and J5 Strataflash which have a typical clear
lock-bits time of 0.5 seconds.

Signed-off-by: Anders Grafström <grfstrm@users.sourceforge.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-06 09:44:54 +01:00
Alexey Korolev
2e489e077a [MTD] [NOR] Add qry_mode_on()/qry_omde_off() to deal with odd chips
There are some CFI chips which require non standard procedures to get 
into QRY mode. The possible way to support them would be trying 
different modes till QRY will be read. This patch introduce two new 
functions qry_mode_on qry_mode_off. qry_mode_on tries different commands 
in order switch chip into QRY mode.

So if we have one more "odd" chip - we just could add several lines to 
qry_mode_on. Also using these functions remove unnecessary code 
duplicaton in porbe procedure.

Currently there are two "odd" cases
1. Some old intel chips which require 0xFF before 0x98
2. ST M29DW chip which requires 0x98 to be sent at 0x555 (according to
CFI should be 0x55)

This patch is partialy based on the patch from Uwe
(see "[PATCH 2/4] [RFC][MTD] cfi_probe: remove Intel chip workaround"
thread )

Signed-off-by: Alexey Korolev <akorolev@infradead.org>
Signed-off-by: Alexander Belyakov <abelyako@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-06 09:43:58 +01:00
Adrian Hunter
feb2f55db4 [MTD] [OneNAND] Add defines for HF and sync write
Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-08-01 22:06:15 +01:00
David Brownell
95b1bc2053 [MTD] MTD_DEBUG always does compile-time typechecks
The current style for debug messages is to ensure they're always
parsed by the compiler and then subjected to dead code removal.
That way builds won't break only when debug options get enabled,
which is common when they are stripped out early by CPP.

This patch makes CONFIG_MTD_DEBUG adopt that convention.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-07-30 14:21:05 +01:00
Alexey Korolev
96d8b647cf [MTD] [NAND] fix subpage read for small page NAND
Current implementation of subpage read feature for NAND has issues with
small page devices. Small page NAND do not support RNDOUT command.
So subpage feature is not applicable for them.

This patch disables support of subpage for small page NAND.
The code is verified on nandsim(SP NAND simulation) and on LP NAND
devices.

Thanks a lot to Artem for finding this issue.

Signed-off-by: Alexey Korolev <akorolev@infradead.org>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-07-30 11:59:24 +01:00
Alexey Korolev
3d45955962 [MTD] [NAND] subpage read feature as a way to increase performance.
This patch enables NAND subpage read functionality.
If upper layer drivers are requesting to read non page aligned data NAND
subpage-read functionality reads the only whose ECC regions which include
requested data when original code reads whole page.
This significantly improves performance in many cases.

Here are some digits :

UBI volume mount time
No subpage reads: 5.75 seconds
Subpage read patch: 2.42 seconds

Open/stat time for files on JFFS2 volume:
No subpage read  0m 5.36s
Subpage read     0m 2.88s

Signed-off-by Alexey Korolev <akorolev@infradead.org>
Acked-by: Artem Bityutskiy <dedekind@infradead.org>
Acked-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-07-25 10:49:50 -04:00
David Woodhouse
ff877ea80e Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6 2008-07-25 10:40:14 -04:00
Artem Bityutskiy
85c6e6e282 UBI: amend commentaries
Hch asked not to use "unit" for sub-systems, let it be so.
Also some other commentaries modifications.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:32:56 +03:00
Artem Bityutskiy
a5bf619041 UBI: add ubi_sync() interface
To flush MTD device caches.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24 13:32:56 +03:00
Greg Kroah-Hartman
eadcf0d704 MTD: handle pci_name() being const
This changes the MTD core to handle pci_name() now returning a constant
string.

Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-21 21:55:03 -07:00
David Woodhouse
a8931ef380 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2008-07-11 14:36:25 +01:00
David Woodhouse
44d1b980c7 Fix various old email addresses for dwmw2
Although if people have questions about ARCnet, perhaps it's _better_
for them to be mailing dwmw2@cam.ac.uk about it...

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06 11:29:10 -07:00
Adrian Bunk
59018b6d2a MTD/JFFS2: remove CVS keywords
Once upon a time, the MTD repository was using CVS.

This patch therefore removes all usages of the no longer updated CVS
keywords from the MTD code.

This also includes code that printed them to the user.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-06-04 17:50:17 +01:00
Jared Hulbert
a98889f3d8 [MTD][NOR] Add physical address to point() method
Adding the ability to get a physical address from point() in addition
to virtual address.  This physical address is required for XIP of
userspace code from flash.

Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
Reviewed-by: Jörn Engel <joern@logfs.org>
Acked-by: Nicolas Pitre <nico@cam.org>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-05-01 18:59:11 +01:00
Robert P. J. Day
fb96c00819 [MTD] Delete long-unused jedec.h header file.
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-26 18:48:30 +01:00
Florian Fainelli
757570063a [MTD] [MAPS] Extend plat-ram to support a supplied probe type
This enhances plat-ram to take a map_probes argument in
the platform_data structure which allow plat-ram to support
any direct-mapped device that MTD supports (jedec, cfi, amd ..)

A few items are also fixed:
- Don't panic if probes is 0
- Actually use the partition list that is passed in

Signed-off-by: Florian Fainelli <florian.fainelli@telecomint.eu>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-22 20:10:10 +01:00
Adrian Bunk
607d1cb104 [MTD] [OneNAND] proper onenand_bbt_read_oob() prototype
This patch adds a proper prototype for onenand_bbt_read_oob() in
include/linux/mtd/onenand.h

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-22 15:59:13 +01:00
Adrian Bunk
51ee83df61 [MTD] proper prototypes for nftl_{read,write}_oob()
This patch adds proper prototypes for nftl_{read,write}_oob() in
include/linux/mtd/nftl.h

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-22 15:54:29 +01:00
Adrian Bunk
a8e8aa2569 [MTD] proper prototypes for inftl_{read,write}_oob()
This patch adds proper prototypes for inftl_{read,write}_oob() in
include/linux/mtd/inftl.h

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-04-22 15:54:16 +01:00
Richard Purdie
388bbb09b9 [MTD] Add mtd panic_write function pointer
MTDs are well suited for logging critical data and the mtdoops driver
allows kernel panics/oops to be written to flash in a blackbox flight
recorder fashion allowing better debugging and analysis of crashes.

Any kernel oops in user context can be easily handled since the kernel
continues as normal and any queued mtd writes are scheduled. Any kernel
oops in interrupt context results in a panic and the delayed writes will
not be scheduled however. The existing mtd->write function cannot be
called in interrupt context so these messages can never be written to
flash.

This patch adds a panic_write function pointer that drivers can
optionally implement which can be called in interrupt context. It is
only intended to be called when its known the kernel is about to panic
and we need to write to succeed. Since the kernel is not going to be
running for much longer, this function can break locks and delay to
ensure the write succeeds (but not sleep).

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-02-07 10:30:48 +00:00
David Woodhouse
6208e77e7f Merge git://git.infradead.org/~dedekind/ubi-2.6 2008-02-03 22:07:40 +11:00
David Woodhouse
b7e23d913a Merge git://git.infradead.org/~kmpark/onenand-mtd-2.6 2008-02-03 18:31:04 +11:00
Scott Wood
9a310d2119 [MTD] Factor out OF partition support from the NOR driver.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-02-03 18:06:48 +11:00
Kyungmin Park
e71f04fc92 [MTD] [OneNAND] Get correct density from device ID
Use the higher bits for other purpose.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
2008-01-29 17:11:38 +09:00
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
Bartlomiej Sieka
de7921f01a [MTD] [NOR] Fix incorrect interface code for x16/x32 chips
According to "Common Flash Memory Interface Publication 100" dated December 1,
2001, the interface code for x16/x32 chips is 0x0005, and not 0x0004 used so
far.

Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-01-10 22:07:12 +00:00
Artem Bityutskiy
393852ecfe UBI: add ubi_leb_map interface
The idea of this interface belongs to Adrian Hunter. The
interface is extremely useful when one has to have a guarantee
that an LEB will contain all 0xFFs even in case of an unclean
reboot. UBI does have an 'ubi_leb_erase()' call which may do
this, but it is stupid and ineffecient, because it flushes whole
queue. I should be re-worked to just be a pair of unmap,
map calls.

The user of the interfaci is UBIFS at the moment.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26 19:15:14 +02:00
Jesper Nilsson
a66f66c44d [MTD] Provide mtdram.h with mtdram_init_device() prototype
This is used by axisflashmap.c to boot from ram.

Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Mikael Starvik <starvik@axis.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-11-06 08:40:24 +00:00
Kevin Hao
c4a9f88daf [MTD] [NOR] fix ctrl-alt-del can't reboot for intel flash bug
When we press ctrl-alt-del,kernel_restart_prepare will invoke 
cfi_intelext_reboot which will set flash to read array mode, but later 
when device_shutdown is invoked which may put current work queue to 
sleep and other process may be scheduled to running and programming 
flash in not FL_READY mode again. So we can't boot up if this flash is 
used for bootloader.

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-10-13 14:36:18 +01:00
Jörn Engel
b38178ee71 [MTD] Document erase interface.
Document mtd erase interface.

Signed-off-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-09-21 14:48:33 +01:00
David Woodhouse
241651d04d [MTD] Fix CFI build error when no map width or interleave supported
When building NOR flash support, you have compile-time options for the
bus width and the number of individual chips which are interleaved
together onto that bus. The code to deal with arbitrary geometry is a
bit convoluted, and people want to just configure it for the specific
hardware they have, to avoid the runtime overhead.

Selecting _none_ of the available options doesn't make any sense. You
should have at least one. This makes it build though, since people
persist in trying.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-09-06 09:40:21 +01:00
Steven J. Hill
30eb0db07d [MTD] [NAND] Add NAND manufacturer AMD.
This patch adds the manufacturer ID for AMD flash.

Signed-off-by: Steven J. Hill <sjhill1@rockwellcollins.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-07-23 11:51:53 +01:00
Kyungmin Park
ee9745fcf2 [MTD] [OneNAND] 2X program support
The 2X Program is an extension of Program Operation.

Since the device is equipped with two DataRAMs, and two-plane NAND Flash 
memory array, these two component enables simultaneous program of 4KiB.
Plane1 has only even blocks such as block0, block2, block4 while Plane2 
has only odd blocks such as block1, block3, block5.
So MTD regards it as 4KiB page size and 256KiB block size

Now the following chips support it. (KFXXX16Q2M)
Demux: KFG2G16Q2M, KFH4G16Q2M, KFW8G16Q2M,
Mux:   KFM2G16Q2M, KFN4G16Q2M,

And more recent chips

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-06-30 08:24:57 +01:00
David Howells
acaebfd8a7 [MTD] generalise the handling of MTD-specific superblocks
Generalise the handling of MTD-specific superblocks so that JFFS2 and ROMFS
can both share it.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-05-11 12:14:15 +01:00
Robert P. J. Day
42f209d3c9 [MTD] Delete allegedly obsolete "bank_size" field of mtd_info.
Delete the allegedly obsolete "bank_size" member of struct mtd_info.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-05-09 13:26:52 +01:00
Robert P. J. Day
36200b7600 [MTD] Remove unnecessary user space check from mtd.h.
Since the header file include/linux/mtd/mtd.h is not exported to user
space, remove the user space check and error.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-05-09 13:24:37 +01:00
Vitaly Wool
972edcb79e [MTD] [NAND] platform NAND driver: update header
This patch extends nand.h in order to enable platform NAND driver.

Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-05-08 00:40:32 +01:00
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
sshahrom@micron.com
8c60e5475d [MTD][NAND] Add Micron Manufacturer ID
Add Micron Manufacturer ID.

Signed-off-by: Shahrom Sharif <sshahrom@micron.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-04-17 18:27:06 +01:00