summaryrefslogtreecommitdiff
path: root/drivers/mtd/Makefile
AgeCommit message (Collapse)Author
2020-05-31mtd: Support kmsg dumper based on pstore/blkWeiXiong Liao
This introduces mtdpstore, which is similar to mtdoops but more powerful. It uses pstore/blk, and aims to store panic and oops logs to a flash partition, where pstore can later read back and present as files in the mounted pstore filesystem. To make mtdpstore work, the "blkdev" of pstore/blk should be set as MTD device name or MTD device number. For more details, see Documentation/admin-guide/pstore-blk.rst This solves a number of issues: - Work duplication: both of pstore and mtdoops do the same job storing panic/oops log. They have very similar logic, registering to kmsg dumper and storing logs to several chunks one by one. - Layer violations: drivers should provides methods instead of polices. MTD should provide read/write/erase operations, and allow a higher level drivers to provide the chunk management, kmsg dump configuration, etc. - Missing features: pstore provides many additional features, including presenting the logs as files, logging dump time and count, and supporting other frontends like pmsg, console, etc. Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com> Link: https://lore.kernel.org/lkml/20200511233229.27745-11-keescook@chromium.org/ Link: https://lore.kernel.org/r/1589266715-4168-1-git-send-email-liaoweixiong@allwinnertech.com Signed-off-by: Kees Cook <keescook@chromium.org>
2019-09-15mtd: parsers: Move CMDLINE parserLinus Walleij
This moves the CMDLINE partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15mtd: parsers: Move OF parserLinus Walleij
This moves the OF/device tree partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15mtd: parsers: Move BCM63xx parserLinus Walleij
This moves the BCM63xx partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15mtd: parsers: Move BCM47xx parserLinus Walleij
This moves the BCM47xx partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-09-15mtd: parsers: Move TI AR7 parserLinus Walleij
This moves the TI AR7 partition parser down into the parser subdirectory. No functional change. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2019-06-27mtd: Add support for HyperBus memory devicesVignesh Raghavendra
Cypress' HyperBus is Low Signal Count, High Performance Double Data Rate Bus interface between a host system master and one or more slave interfaces. HyperBus is used to connect microprocessor, microcontroller, or ASIC devices with random access NOR flash memory (called HyperFlash) or self refresh DRAM (called HyperRAM). Its a 8-bit data bus (DQ[7:0]) with Read-Write Data Strobe (RWDS) signal and either Single-ended clock(3.0V parts) or Differential clock (1.8V parts). It uses ChipSelect lines to select b/w multiple slaves. At bus level, it follows a separate protocol described in HyperBus specification[1]. HyperFlash follows CFI AMD/Fujitsu Extended Command Set (0x0002) similar to that of existing parallel NORs. Since HyperBus is x8 DDR bus, its equivalent to x16 parallel NOR flash with respect to bits per clock cycle. But HyperBus operates at >166MHz frequencies. HyperRAM provides direct random read/write access to flash memory array. But, HyperBus memory controllers seem to abstract implementation details and expose a simple MMIO interface to access connected flash. Add support for registering HyperFlash devices with MTD framework. MTD maps framework along with CFI chip support framework are used to support communicating with flash. Framework is modelled along the lines of spi-nor framework. HyperBus memory controller (HBMC) drivers calls hyperbus_register_device() to register a single HyperFlash device. HyperFlash core parses MMIO access information from DT, sets up the map_info struct, probes CFI flash and registers it with MTD framework. Some HBMC masters need calibration/training sequence[3] to be carried out, in order for DLL inside the controller to lock, by reading a known string/pattern. This is done by repeatedly reading CFI Query Identification String. Calibration needs to be done before trying to detect flash as part of CFI flash probe. HyperRAM is not supported at the moment. HyperBus specification can be found at[1] HyperFlash datasheet can be found at[2] [1] https://www.cypress.com/file/213356/download [2] https://www.cypress.com/file/213346/download [3] http://www.ti.com/lit/ug/spruid7b/spruid7b.pdf Table 12-5741. HyperFlash Access Sequence Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
2019-05-06mtd: afs: Move AFS partition parser to parsers subdirLinus Walleij
This moves the AFS (ARM Firmware Suite) partition parser for NOR flash down into the parsers subdirectory. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2018-11-12mtd: Move Redboot partition parserLinus Walleij
This moves the Redboot partition parser down to the parsers subdirectory. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
2018-03-15mtd: Move onenand code base to drivers/mtd/nand/onenandBoris Brezillon
Move onenand code base to the drivers/mtd/nand directory in the hope that someday someone will patch it to use the generic NAND helpers. If it never happens, at least we'll have all NAND related support in a single directory and not spread over the drivers/mtd/ directory. Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-22mtd: extract TRX parser out of bcm47xxpart into a separated moduleRafał Miłecki
This makes TRX parsing code reusable with other platforms and parsers. Please note this patch doesn't really change anything in the existing code, just moves it. There is still some place for improvement (e.g. working on non-hacky method of checking rootfs format) but it's not really a subject of this change. Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2014-04-14mtd: spi-nor: shorten Kconfig namingBrian Norris
Signed-off-by: Brian Norris <computersforpeace@gmail.com> Reviewed-by: Marek Vasut <marex@denx.de> Acked-by: Huang Shijie <b32955@freescale.com>
2014-04-14mtd: spi-nor: add the framework for SPI NORHuang Shijie
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: Huang Shijie <b32955@freescale.com> Acked-by: Marek Vasut <marex@denx.de> [Brian: rebased to include additional m25p_ids[] entry] Signed-off-by: Brian Norris <computersforpeace@gmail.com>
2013-04-05mtd: merge mtdchar module with mtdcoreArtem Bityutskiy
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: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2012-09-29mtd: bcm47part driver for BCM47XX chipsetsRafał Miłecki
This driver provides parser detecting partitions on BCM47XX flash memories. It has many differences in comparison to BCM63XX, like: 1) Different CFE with no more trivial MAGICs 2) More partitions types (board_data, ML, POT) 3) Supporting more than 1 flash on a device which resulted in decision of writing new parser. It uses generic mtd interface and was successfully tested with Netgear WNDR4500 router which has 2 flash memories: serial one and NAND one. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2012-01-09mtd: maps: bcm963xx-flash: make CFE partition parsing an mtd parserJonas Gorski
Recent BCM63XX devices support a variety of flash types (parallel, SPI, NAND) and share the partition layout. To prevent code duplication make the CFE partition parsing code a stand alone mtd parser to allow SPI or NAND flash drivers to use it. Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com> Acked-by: Florian Fainelli <florian@openwrt.org> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2011-09-11mtd: make ofpart buildable as a separate moduleDmitry Eremin-Solenikov
As ofpart now uses a standard mtd partitions parser interface, make it buildable as a separate module. Also provide MODULE_DESCRIPTION and MODULE_AUTHOR for this module. Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Artem Bityutskiy <dedekind1@gmail.com>
2011-05-25mtd: kill CONFIG_MTD_PARTITIONSJamie Iles
Now that none of the drivers use CONFIG_MTD_PARTITIONS we can remove it from Kconfig and the last remaining uses. Signed-off-by: Jamie Iles <jamie@jamieiles.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2011-03-11mtd: Add mtdswap block driverJarkko Lavinen
Add a driver for allowing an mtd device to be used as a block device for swapping. The block device is volatile, and the mapping of swapped pages is not stored on flash. Signed-off-by: Jarkko Lavinen <jarkko.lavinen@nokia.com> Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2011-03-11mtd: make MTD_CONCAT support mandatoryDmitry Eremin-Solenikov
Move mtdconcat to be an integral part of the mtd core. It's a tiny bit of code, which bears 'say Y if you don't know what to do' note in the Kconfig. OTOH there are several ugly ifdefs depending on the MTD_CONCAT. So, making MTD_CONCAT support mandatory will allow us to clean up code a lot. Kconfig entry is changed to be a bool defaulting to Y, so all code pieces depending on it, will have MTD_CONCAT Kconfig symbol and CONFIG_MTD_CONCAT define. This will be removed in one of next patches. Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Acked-by: Stefan Roese <sr@denx.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-12-03mtd: Fix MTD_OF_PARTS for all arch and minor tidy of MTD_PARTITIONSGrant Likely
MTD_OF_PARTS should be possible on all architectures, not just powerpc and microblaze, and it probably should not be a user selectable option. Neither does it need to be in a separate module. Also, rework MTD Kconfig to group options dependant on MTD_PARTITIONS into a if/endif block. Do the same for MTD_REDBOOT_PARTS. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-05-10Merge branch 'master' of ↵David Woodhouse
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: drivers/mtd/mtdcore.c Pull in the bdi fixes and ARM platform changes that other outstanding patches depend on.
2010-04-27Move mtd_bdi_*mappable to mtdcore.cJörn Engel
Removes one .h and one .c file that are never used outside of mtdcore.c. Signed-off-by: Joern Engel <joern@logfs.org> Edited to remove on leftover debug define. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26mtd: Add new SmartMedia/xD FTLMaxim Levitsky
This implements new readwrite SmartMedia/xd FTL. mtd driver must have support proper ECC and badblock verification based on oob parts for 512 bytes nand. Also mtd driver must define read_oob and write_oob, which are used to read and write both data and oob together. Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-03-24NOMMU: Present backing device capabilities for MTD chardevsDavid Howells
Present backing device capabilities for MTD character device files to allow NOMMU mmap to do direct mapping where possible. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Bernd Schmidt <bernd.schmidt@analog.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2009-01-05Merge branch 'master' of git://git.infradead.org/users/dedekind/mtd-tests-2.6David Woodhouse
Conflicts: drivers/mtd/Makefile
2009-01-05[MTD] LPDDR Makefile and KConfigAlexey Korolev
We have two components to manage LPDDR flash memories in Linux. 1. It is a driver for chip probing and reading its capabilities 2. It is a device operations driver. Signed-off-by: Alexey Korolev <akorolev@infradead.org> Acked-by: Jared Hulbert <jaredeh@gmail.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-12-10MTD: add MTD tests to compilationArtem Bityutskiy
Add MTD tests to Kconfig and Makefiles. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-04-22[MTD] AR7 mtd partition mapMatteo Croce
Signed-off-by: Matteo Croce <technoboy85@gmail.com> Signed-off-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Eugene Konev <ejka@imfi.kspu.ru> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2008-02-03[MTD] Factor out OF partition support from the NOR driver.Scott Wood
Signed-off-by: Scott Wood <scottwood@freescale.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-08-23Merge branch 'master' of ↵David Woodhouse
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
2007-08-03[MTD] Makefile fix for mtdsuperSatyam Sharma
We want drivers/mtd/{mtdcore, mtdsuper, mtdpart}.c to be built and linked into the same mtd.ko module. Fix the Makefile to ensure this, and remove duplicate MODULE_ declarations in mtdpart.c, as mtdcore.c already has them. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-06-28[MTD] oops and panic message logging to MTD deviceRichard Purdie
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: Richard Purdie <rpurdie@openedhand.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-05-11[MTD] generalise the handling of MTD-specific superblocksDavid Howells
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>
2007-04-27UBI: Unsorted Block ImagesArtem B. Bityutskiy
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>
2006-11-29[MTD] add MTD_BLKDEVS Kconfig optionJosh Boyer
Add a MTD_BLKDEVS Kconfig option to cleanup the makefile a bit Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>
2006-09-22[MTD] Add SSFDC (SmartMedia) read-only translation layerClaudio Lanconelli
Signed-off-by: Claudio Lanconelli <lanconelli.claudio@eptar.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2005-11-06[MTD] Add initial support for OneNAND flash chipsKyungmin Park
OneNAND is a new flash technology from Samsung with integrated SRAM buffers and logic interface. Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2005-11-06[MTD] Add Resident Flash Disk (RFD) supportSean Young
This type of flash translation layer (FTL) is used by the Embedded BIOS by General Software. It is known as the Resident Flash Disk (RFD), see: http://www.gensw.com/pages/prod/bios/rfd.htm Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
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!