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* UAPI: Remove empty non-UAPI Kbuild filesDavid Howells2012-10-17
| | | | | | | | | | | | | | | | | | Remove non-UAPI Kbuild files that have become empty as a result of UAPI disintegration. They used to have only header-y lines in them and those have now moved to the Kbuild files in the corresponding uapi/ directories. Possibly these should not be removed but rather have a comment inserted to say they are intentionally left blank. This would make it easier to add generated header lines in future without having to restore the infrastructure. Note that at this point not all the UAPI disintegration parts have been merged, so it is likely that more empty Kbuild files will turn up. It is probably necessary to make the files non-empty to prevent the patch program from automatically deleting them when it reduces them to nothing. Signed-off-by: David Howells <dhowells@redhat.com>
* UAPI: (Scripted) Disintegrate include/mtdDavid Howells2012-10-09
| | | | | | | | | Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com>
* UBI: add max_beb_per1024 to attach ioctlRichard Genoud2012-09-04
| | | | | | | | | This patch provides a possibility to set the "maximum expected number of bad blocks per 1024 blocks" (max_beb_per1024) for each mtd device using the UBI_IOCATT ioctl. Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBI: amend commentaries WRT dtypeArtem Bityutskiy2012-05-20
| | | | | | | | | | | Richard removed the "dtype" hint, but few commentaries were left and this patch removes them. I've also added a better description about the "dtype" field in the ubi-user.h for people who may ever wonder what was that dtype thing about. This patch also adds an important note that it is better to use value "3" for the "dtype" field. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* UBI: remove data type hint from ubi-user.hRichard Weinberger2012-05-20
| | | | | | | | | This finally removes the data type hint from the UBI ABI. >From now on the "dtype" field will be ignored and must not used anymore. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
* mtd: document that MEMWRITE ioctl is NAND-specificArtem Bityutskiy2012-01-09
| | | | | Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: kill old field for `struct mtd_info_user'Brian Norris2011-09-11
| | | | | | | | | The ecctype and eccsize fields have been obsolete for a while. Since they don't have any users, we can kill them and leave padding in their place for now. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: document ABIBrian Norris2011-09-11
| | | | | | | | | | | | | We're missing a lot of important documentation in include/mtd/mtd-abi.h: * add a simple description of each ioctl (feel free to expand!) * give full explanations of recently added and modified operations * explain the usage of "RAW" that appear in different modes and types of operations * fix some comment style along the way Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: add MEMWRITE ioctlBrian Norris2011-09-11
| | | | | | | | | | | | | | | | | | | | | | | | | | Implement a new ioctl for writing both page data and OOB to flash at the same time. This ioctl is intended to be a generic interface that can replace other ioctls (MEMWRITEOOB and MEMWRITEOOB64) and cover the functionality of several other old ones, e.g., MEMWRITE can: * write autoplaced OOB instead of using ECCGETLAYOUT (deprecated) and working around the reserved areas * write raw (no ECC) OOB instead of using MTDFILEMODE to set the per-file-descriptor MTD_FILE_MODE_RAW * write raw (no ECC) data instead of using MTDFILEMODE (MTD_FILE_MODE_RAW) and using standard character device "write" This ioctl is especially useful for MLC NAND, which cannot be written twice (i.e., we cannot successfully write the page data and OOB in two separate operations). Instead, MEMWRITE can write both in a single operation. Note that this ioctl is not affected by the MTD file mode (i.e., MTD_FILE_MODE_RAW vs. MTD_FILE_MODE_NORMAL), since it receives its write mode as an input parameter. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: rename MTD_MODE_* to MTD_FILE_MODE_*Brian Norris2011-09-11
| | | | | | | | | | | | | | | | These modes hold their state only for the life of their file descriptor, and they overlap functionality with the MTD_OPS_* modes. Particularly, MTD_MODE_RAW and MTD_OPS_RAW cover the same function: to provide raw (i.e., without ECC) access to the flash. In fact, although it may not be clear, MTD_MODE_RAW implied that operations should enable the MTD_OPS_RAW mode. Thus, we should be specific on what each mode means. This is a start, where MTD_FILE_MODE_* actually represents a "file mode," not necessarily a true global MTD mode. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: rename MTD_OOB_* to MTD_OPS_*Brian Norris2011-09-11
| | | | | | | | | | These modes are not necessarily for OOB only. Particularly, MTD_OOB_RAW affected operations on in-band page data as well. To clarify these options and to emphasize that their effect is applied per-operation, we change the primary prefix to MTD_OPS_. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: move mtd_oob_mode_t to shared kernel/user spaceBrian Norris2011-09-11
| | | | | | | | | | | | | We will want to use the MTD_OOB_{PLACE,AUTO,RAW} modes in user-space applications through the introduction of new ioctls, so we should make this enum a shared type. This enum is now anonymous. Artem: tweaked the patch. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* mtd: remove MEMSETOOBSEL macro definitionBrian Norris2011-09-11
| | | | | | | | | | | | | MEMSETOOBSEL is completely unused and useless. Remove the definition. Note: it's probably best not to use this ioctl number in the future for MTD, since that may cause conflicts between old kernels and new user software (or new kernels and old user software). Artem: leave a comment about MEMSETOOBSEL. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
* UBI: fix minor stylistic issuesArtem Bityutskiy2011-04-14
| | | | | | | | | | 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>
* UBI: use __packed instead of __attribute__((packed))Artem Bityutskiy2011-04-14
| | | | | | | | | | | | | | | | | | | 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>
* UBI: cleanup comments around volume propertiesArtem Bityutskiy2011-04-14
| | | | | | | 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>
* UBI: re-name set volume properties ioctlArtem Bityutskiy2011-04-14
| | | | | | | | | | | | | | | | | | | 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>
* mtd: Define MLC Flash as a different flash typeRohit Hassan Sathyanarayan2010-10-24
| | | | | | | | | | | MLC NAND Flash has a different cell structure and differs in functioning than the SLC NAND Flash. Hence we are considering it as a different Flash type. Signed-off-by: Rohit H.S <rohit.hs@samsung.com> Signed-off-by: Raghav Gupta <gupta.raghav@samsung.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: edit comments on deprecation of ioctl ECCGETLAYOUTBrian Norris2010-10-24
| | | | | | | | | | | | | | | | | There were some improvements and additions necessary in the comments explaining of the expansion of nand_ecclayout, the introduction of nand_ecclayout_user, and the deprecation of the ioctl ECCGETLAYOUT. Also, I found a better placement for the macro MTD_MAX_ECCPOS_ENTRIES; next to the definition of MTD_MAX_OOBFREE_ENTRIES in mtd-abi.h. The macro is really only important for the ioctl code (found in drivers/mtd/mtdchar.c) but since there are small edits being made to the user-space header, I figured this is a better location. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: nand: expand nand_ecc_layout, deprecate ioctl ECCGETLAYOUTBrian Norris2010-10-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | struct nand_ecclayout is too small for many new chips; OOB regions can be as large as 448 bytes and may increase more in the future. Thus, copying that struct to user-space with the ECCGETLAYOUT ioctl is not a good idea; the ioctl would have to be updated every time there's a change to the current largest size. Instead, the old nand_ecclayout is renamed to nand_ecclayout_user and a new struct nand_ecclayout is created that can accomodate larger sizes and expand without affecting the user-space. struct nand_ecclayout can still be used in board drivers without modification -- at least for now. A new function is provided to convert from the new to the old in order to allow the deprecated ioctl to continue to work with truncated data. Perhaps the ioctl, the conversion process, and the struct nand_ecclayout_user can be removed altogether in the future. Note: There are comments in nand/davinci_nand.c::nand_davinci_probe() regarding this issue; this driver (and maybe others) can be updated to account for extra space. All kernel drivers can use the expanded nand_ecclayout as a drop-in replacement and ignore its benefits. Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: Update copyright noticesDavid Woodhouse2010-08-08
| | | | Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* mtd: add an ioctl to query the lock status of a flash sectorRichard Cochran2010-08-02
| | | | | | | | | | This patchs adds a way for user space programs to find out whether a flash sector is locked. An optional driver method in the mtd_info struct provides the information. Signed-off-by: Richard Cochran <richard.cochran@omicron.at> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* Kill jffs2-user.hArtem Bityutskiy2009-06-05
| | | | | | | | | | | | | | | This file does not define any kernel-userspace API, all it does it defines few helpers for userspace. Instead, userspace should have a private copy of this file. The main (if not the only) user is the mtd-utils package, but it already has a private copy of this file. This patch also removes references to 'jffs2-user.h' from 'Kbuild' and MAINTAINERS' files. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: add OOB ioctls for >4GiB devicesKevin Cernekee2009-05-29
| | | | | | Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* mtd: add MEMERASE64 ioctl for >4GiB devicesKevin Cernekee2009-05-29
| | | | | | | | | New MEMERASE/MEMREADOOB/MEMWRITEOOB ioctls are needed in order to support 64-bit offsets into large NAND flash devices. Signed-off-by: Kevin Cernekee <kpc.mtd@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
* make MTD headers use strict integer typesArnd Bergmann2009-03-26
| | | | | | | | | | | 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>
* make exported headers use strict posix typesArnd Bergmann2009-03-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | A number of standard posix types are used in exported headers, which is not allowed if __STRICT_KERNEL_NAMES is defined. In order to get rid of the non-__STRICT_KERNEL_NAMES part and to make sane headers the default, we have to change them all to safe types. There are also still some leftovers in reiserfs_fs.h, elfcore.h and coda.h, but these files have not compiled in user space for a long time. This leaves out the various integer types ({u_,u,}int{8,16,32,64}_t), which we take care of separately. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Cc: David Airlie <airlied@linux.ie> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Cc: netdev@vger.kernel.org Cc: linux-ppp@vger.kernel.org Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: David Woodhouse <dwmw2@infradead.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* headers_check fix: mtd/inftl-user.hJaswinder Singh Rajput2009-01-30
| | | | | | | | fix the following 'make headers_check' warning: usr/include/mtd/inftl-user.h:61: found __[us]{8,16,32,64} type without #include <linux/types.h> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
* UBI: allow direct user-space I/OSidney Amani2009-01-27
| | | | | | | | | | | 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>
* UBI: improve ioctl commentariesArtem Bityutskiy2009-01-18
| | | | Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBI: add ioctl for is_mapped operationCorentin Chary2009-01-18
| | | | | | | | | | | 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>
* UBI: add ioctl for unmap operationCorentin Chary2009-01-18
| | | | | | | | | | | 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>
* UBI: add ioctl for map operationCorentin Chary2009-01-18
| | | | | | | | | | | 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>
* trivial: fix then -> than typos in comments and documentationFrederik Schwarzer2009-01-06
| | | | | | | - (better, more, bigger ...) then -> (...) than Signed-off-by: Frederik Schwarzer <schwarzerf@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* Merge branch 'linux-next' of git://git.infradead.org/~dedekind/ubi-2.6David Woodhouse2008-07-25
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| * UBI: fix checkpatch.pl errors and warningsArtem Bityutskiy2008-07-24
| | | | | | | | | | | | | | | | 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>
| * UBI: implement multiple volumes renameArtem Bityutskiy2008-07-24
| | | | | | | | | | | | | | 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>
* | MTD/JFFS2: remove CVS keywordsAdrian Bunk2008-06-04
|/ | | | | | | | | | | | 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>
* UBI: make ubi-header.h localArtem Bityutskiy2008-04-17
| | | | | | | | | | | The new trend in linux is not to store headers which define on-media format in the include/ directory, but instead, store them locally. This is because these headers "do not define any kernel<->userspace interface". Do so for UBI as well. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* Merge git://git.infradead.org/~dedekind/ubi-2.6David Woodhouse2008-02-03
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| * UBI: introduce atomic LEB change ioctlArtem Bityutskiy2008-01-25
| | | | | | | | | | | | | | | | | | 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>
| * UBI: add layout volume informationArtem Bityutskiy2008-01-25
| | | | | | | | | | | | | | | | Add more information about layout volume to make userspace tools use the macros instead of constants. Also rename UBI_LAYOUT_VOL_ID to make it consistent with other macros. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
| * UBI: add auto-resize featureArtem Bityutskiy2008-01-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem: NAND flashes have different amount of initial bad physical eraseblocks (marked as bad by the manufacturer). For example, for 256MiB Samsung OneNAND flash there might be from 0 to 40 bad initial eraseblocks, which is about 2%. When UBI is used as the base system, one needs to know the exact amount of good physical eraseblocks, because this number is needed to create the UBI image which is put to the devices during production. But this number is not know, which forces us to use the minimum number of good physical eraseblocks. And UBI additionally reserves some percentage of physical eraseblocks for bad block handling (default is 1%), so we have 1-3% of PEBs reserved at the end, depending on the amount of initial bad PEBs. But it is desired to always have 1% (or more, depending on the configuration). Solution: this patch adds an "auto-resize" flag to the volume table. The volume which has the "auto-resize" flag will automatically be re-sized (enlarged) on the first UBI initialization. UBI clears the flag when the volume is re-sized. Only one volume may have the "auto-resize" flag. So, the production UBI image may have one volume with "auto-resize" flag set, and its size is automatically adjusted on the first boot of the device. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* | [MTD] Unlocking all Intel flash that is locked on power up.Justin Treon2008-02-03
|/ | | | | | | | | | | | | | | | | | Patch for unlocking all Intel flash that has instant locking on power up. The patch has been tested on Intel M18, P30 and J3D Strata Flash. 1. The automatic unlocking can be disabled for a particular partition in the map or the command line. a. For the bit mask in the map it should look like: .mask_flags = MTD_POWERUP_LOCK, b. For the command line parsing it should look like: mtdparts=0x80000(bootloader)lk 2. This will only unlock parts with instant individual block locking. Intel parts with legacy unlocking will not be unlocked. Signed-off-by: Justin Treon <justin_treon@yahoo.com> Signed-off-by: Jared Hulbert <jaredeh@gmail.com> Acked-by: Nicolas Pitre <nico@cam.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* UBI: introduce attach ioctlsArtem Bityutskiy2007-12-26
| | | | Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBI: kill homegrown endian macrosChristoph Hellwig2007-07-18
| | | | | | | | Kill UBI's homegrown endianess handling and replace it with the standard kernel endianess handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* UBI: Unsorted Block ImagesArtem B. Bityutskiy2007-04-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [MTD] remove unused ecctype,eccsize fields from struct mtd_infoArtem Bityutskiy2007-02-09
| | | | | | | | | | | | Remove unused and broken mtd->ecctype and mtd->eccsize fields from struct mtd_info. Do not remove them from userspace API data structures (don't want to breake userspace) but mark them as obsolete by a comment. Any userspace program which uses them should be half-broken anyway, so this is more about saving data structure size. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* Merge branch 'master' of ↵David Woodhouse2006-10-01
|\ | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Manually resolve conflict in include/mtd/Kbuild Signed-off-by: David Woodhouse <dwmw2@infradead.org>
| * Merge git://git.infradead.org/~dwmw2/hdronelineLinus Torvalds2006-09-22
| |\ | | | | | | | | | | | | | | | | | | * git://git.infradead.org/~dwmw2/hdroneline: [HEADERS] One line per header in Kbuild files to reduce conflicts Manual (trivial) conflict resolution in include/asm-s390/Kbuild
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