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  1. 15 4月, 2014 1 次提交
    • H
      mtd: spi-nor: add the framework for SPI NOR · b199489d
      由 Huang Shijie 提交于 
      This patch cloned most of the m25p80.c. In theory, it adds a new spi-nor layer.

Before this patch, the layer is like:

                   MTD
         ------------------------
                  m25p80
         ------------------------
	       spi bus driver
         ------------------------
	        SPI NOR chip

After this patch, the layer is like:
                   MTD
         ------------------------
                  spi-nor
         ------------------------
                  m25p80
         ------------------------
	       spi bus driver
         ------------------------
	       SPI NOR chip

With the spi-nor controller driver(Freescale Quadspi), it looks like:
                   MTD
         ------------------------
                  spi-nor
         ------------------------
                fsl-quadspi
         ------------------------
	       SPI NOR chip

New APIs:
   spi_nor_scan: used to scan a spi-nor flash.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Acked-by: NMarek Vasut <marex@denx.de>
[Brian: rebased to include additional m25p_ids[] entry]
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
      b199489d
  3. 05 4月, 2013 1 次提交
    • A
      mtd: merge mtdchar module with mtdcore · 660685d9
      由 Artem Bityutskiy 提交于 
      The MTD subsystem has historically tried to be as configurable as possible. The
side-effect of this is that its configuration menu is rather large, and we are
gradually shrinking it. For example, we recently merged partitions support with
the mtdcore.

This patch does the next step - it merges the mtdchar module to mtdcore. And in
this case this is not only about eliminating too fine-grained separation and
simplifying the configuration menu. This is also about eliminating seemingly
useless kernel module.

Indeed, mtdchar is a module that allows user-space making use of MTD devices
via /dev/mtd* character devices. If users do not enable it, they simply cannot
use MTD devices at all. They cannot read or write the flash contents. Is it a
sane and useful setup? I believe not. And everyone just enables mtdchar.

Having mtdchar separate is also a little bit harmful. People sometimes miss the
fact that they need to enable an additional configuration option to have
user-space MTD interfaces, and then they wonder why on earth the kernel does
not allow using the flash? They spend time asking around.

Thus, let's just get rid of this module and make it part of mtd core.

Note, mtdchar had additional configuration option to enable OTP interfaces,
which are present on some flashes. I removed that option as well - it saves a
really tiny amount space.

[dwmw2: Strictly speaking, you can mount file systems on MTD devices just
        fine without the mtdchar (or mtdblock) devices; you just can't do
        other manipulations directly on the underlying device. But still I
        agree that it makes sense to make this unconditional. And Yay! we
        get to kill off an instance of checking CONFIG_foo_MODULE, which is
        an abomination that should never happen.]
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
      660685d9
  5. 29 9月, 2012 1 次提交
  7. 10 1月, 2012 1 次提交
  9. 11 9月, 2011 1 次提交
  11. 25 5月, 2011 1 次提交
  13. 11 3月, 2011 2 次提交
  15. 04 12月, 2010 1 次提交
  17. 27 4月, 2010 1 次提交
  19. 27 2月, 2010 1 次提交
  21. 24 3月, 2009 1 次提交
  23. 05 1月, 2009 1 次提交
  25. 10 12月, 2008 1 次提交
  27. 23 4月, 2008 1 次提交
  29. 03 2月, 2008 1 次提交
  31. 03 8月, 2007 1 次提交
  33. 29 6月, 2007 1 次提交
    • R
      [MTD] oops and panic message logging to MTD device · 4b23aff0
      由 Richard Purdie 提交于 
      Kernel oops and panic messages are invaluable when debugging crashes.
These messages often don't make it to flash based logging methods (say a
syslog on jffs2) due to the overheads involved in writing to flash.

This patch allows you to turn an MTD partition into a circular log
buffer where kernel oops and panic messages are written to. The messages
are obtained by registering a console driver and checking
oops_in_progress. Erases are performed in advance to maximise the
chances of a saving messages.

To activate it, add console=ttyMTDx to the kernel commandline (where x
is the mtd device number to use).
Signed-off-by: NRichard Purdie <rpurdie@openedhand.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>
      4b23aff0
  35. 11 5月, 2007 1 次提交
  37. 27 4月, 2007 1 次提交
    • A
      UBI: Unsorted Block Images · 801c135c
      由 Artem B. Bityutskiy 提交于 
      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: NArtem B. Bityutskiy <dedekind@linutronix.de>
Signed-off-by: NFrank Haverkamp <haver@vnet.ibm.com>
      801c135c
  39. 29 11月, 2006 1 次提交
  41. 22 9月, 2006 1 次提交
  43. 07 11月, 2005 2 次提交
  45. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      由 Linus Torvalds 提交于 
      Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
      1da177e4