summaryrefslogtreecommitdiff
AgeCommit message (Collapse)Author
2006-10-31UBI - Unsorted Block ImagesFrank Haverkamp
UBI (Latin: "where?") manages multiple logical volumes on a single flash device, specifically supporting NAND flash devices. UBI provides a flexible partitioning concept which still allows for wear-levelling across the whole flash device. In a sense, UBI may be compared to the Logical Volume Manager (LVM). Whereas LVM maps logical sector numbers to physical HDD sector numbers, UBI maps logical eraseblocks to physical eraseblocks. More information may be found in the UBI design documentation: ubidesign.pdf. Which can be found here: http://www.linux-mtd.infradead.org/doc/ubi.html Partitioning/Re-partitioning An UBI volume occupies a certain number of erase blocks. This is limited by a configured maximum volume size, which could also be viewed as the partition size. Each individual UBI volume's size can be changed independently of the other UBI volumes, provided that the sum of all volume sizes doesn't exceed a certain limit. UBI supports dynamic volumes and static volumes. Static volumes are read-only and their contents are protected by CRC check sums. Bad eraseblocks handling UBI transparently handles bad eraseblocks. When a physical eraseblock becomes bad, it is substituted by a good physical eraseblock, and the user does not even notice this. Scrubbing On a NAND flash bit flips can occur on any write operation, sometimes also on read. If bit flips persist on the device, at first they can still be corrected by ECC, but once they accumulate, correction will become impossible. Thus it is best to actively scrub the affected eraseblock, by first copying it to a free eraseblock and then erasing the original. The UBI layer performs this type of scrubbing under the covers, transparently to the UBI volume users. Erase Counts UBI maintains an erase count header per eraseblock. This frees higher-level layers (like file systems) from doing this and allows for centralized erase count management instead. The erase counts are used by the wear-levelling algorithm in the UBI layer. The algorithm itself is exchangeable. Booting from NAND For booting directly from NAND flash the hardware must at least be capable of fetching and executing a small portion of the NAND flash. Some NAND flash controllers have this kind of support. They usually limit the window to a few kilobytes in erase block 0. This "initial program loader" (IPL) must then contain sufficient logic to load and execute the next boot phase. Due to bad eraseblocks, which may be randomly scattered over the flash device, it is problematic to store the "secondary program loader" (SPL) statically. Also, due to bit-flips it may become corrupted over time. UBI allows to solve this problem gracefully by storing the SPL in a small static UBI volume. UBI volumes vs. static partitions UBI volumes are still very similar to static MTD partitions: * both consist of eraseblocks (logical eraseblocks in case of UBI volumes, and physical eraseblocks in case of static partitions; * both support three basic operations - read, write, erase. But UBI volumes have the following advantages over traditional static MTD partitions: * there are no eraseblock wear-leveling constraints in case of UBI volumes, so the user should not care about this; * there are no bit-flips and bad eraseblocks in case of UBI volumes. So, UBI volumes may be considered as flash devices with relaxed restrictions. Where can it be found? Documentation, kernel code and applications can be found in the MTD gits. What are the applications for? The applications help to create binary flash images for two purposes: pfi files (partial flash images) for in-system update of UBI volumes, and plain binary images, with or without OOB data in case of NAND, for a manufacturing step. Furthermore some tools are/and will be created that allow flash content analysis after a system has crashed. Who did UBI? The original ideas, where UBI is based on, were developed by Andreas Arnez, Frank Haverkamp and Thomas Gleixner. Josh W. Boyer and some others were involved too. The implementation of the kernel layer was done by Artem B. Bityutskiy. The user-space applications and tools were written by Oliver Lohmann with contributions from Frank Haverkamp, Andreas Arnez, and Artem. Joern Engel contributed a patch which modifies JFFS2 so that it can be run on a UBI volume. Thomas Gleixner did modifications to the NAND layer and also some to JFFS2 to make it work. Signed-off-by: Frank Haverkamp <haver@vnet.ibm.com>
2006-10-09Fixup whitespaceJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-09-18Report compressed file sizes (including node headers) in mkfs.jffs2 stats.Daniel P. Berrange
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-08-07Add xseqno into jffs2_raw_xref on mkfs.jffs2KaiGai Kohei
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com> Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-08-03Add patch from David Byron for separating source and build directoriesDavid Byron
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-06-21Added 64-bit swapping functionsJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-06-21Fix swab32 to use standard typesJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-06-14Remove crufty autocrap MakefileJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-30Update yet again to latest mtd-abi.h from kernel tree. And fix mtd_debug.c.Josh Boyer
Again. Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-30Add .gitignore fileThomas Gleixner
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2006-05-30Update mtd-abi.h and use new NAND ECC functionalityThomas Gleixner
The NAND rework exposes more information to userspace and has a different mechanism to read raw FLASH contents without ECC. Update nanddump and nandwrite. Use the new ECC statistics ioctl to inform the user about corrected and uncorrectable bitflips. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2006-05-29Update user headers from latest kernel treeJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-27Fix mtd_debug for new upstream mtd-abi.hJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-27Merge git://git.infradead.org/users/joern/utilsJosh Boyer
2006-05-27Update mtd-abi.h from upstream kernel.Josh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-23s/oobblock/writesize/gJoern Engel
Follow the kernel in the rename. Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>
2006-05-17Need to include stdint.h to use standard typesJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-17Switch to using standard types. This is userspace, not kernel.Josh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-17Remove ancient filesystem tool that never went anywhereJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-16Consolidate the swab macros into one locationJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-05-14MTD Utils. (Resubmit as attachment)Steve Finney
Modify nanddump to take a '-n' argument for reading without error correction; also accept hex (and octal) for start and length. Signed-off-by: Steven Finney (sfinney@healthhero.com)
2006-05-14MTD Utils. (Resubmit as attachment)Steve Finney
Modify nandwrite to accept hex argument for "-s" argument; also make an error message more accurate. Signed-off-by: Steven Finney <sfinney@healthhero.com>
2006-05-14MTD Utils. (Resubmit as attachment)Steve Finney
Add a basic usage message to flash_erase.c. Signed-off-by: Steven Finney <sfinney@healthhero.com>
2006-05-14Remove XATTR struct typedefsDavid Woodhouse
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-05-06Add XATTR support to mkfs.jffs2David Woodhouse
Since this is optional, it might as well go in immediately.
2006-05-01Add GPL license textJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-30Fix make installv1.0.0David Woodhouse
2006-04-22Fix mtd_debug after removal of some MTD types and flagsJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-17Update ABI header with latest changes from kernelJosh Boyer
Signed-off-by: Josh Boyer <jwboyer@yoda.jdub.homelinux.org>
2006-04-11Fix cbuf free properly.David Woodhouse
Noted by Dan Berrange. Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-11Fix memory leak in write_regular_file()David Woodhouse
Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-11- Update utils to build from in tree include filesJosh Boyer
- Revert any ebh stuff for now Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-11Add include directory to new mtd-utils repo. This contains all the user spaceJosh Boyer
include files needed for the utils Signed-off-by: Josh Boyer <jwboyer@gmail.com>
2006-04-11Initial commitDavid Woodhouse