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path: root/drivers/mtd/ubi/gluebi.c
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2009-01-18UBI: use nicer 64-bit mathArtem Bityutskiy
Get rid of 'do_div()' and use more user-friendly primitives from 'linux/math64.h'. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-12-10[MTD] update internal API to support 64-bit device sizeAdrian Hunter
MTD internal API presently uses 32-bit values to represent device size. This patch updates them to 64-bits but leaves the external API unchanged. Extending the external API is a separate issue for several reasons. First, no one needs it at the moment. Secondly, whether the implementation is done with IOCTLs, sysfs or both is still debated. Thirdly external API changes require the internal API to be accepted first. Note that although the MTD API will be able to support 64-bit device sizes, existing drivers do not and are not required to do so, although NAND base has been updated. In general, changing from 32-bit to 64-bit values cause little or no changes to the majority of the code with the following exceptions: - printk message formats - division and modulus of 64-bit values - NAND base support - 32-bit local variables used by mtdpart and mtdconcat - naughtily assuming one structure maps to another in MEMERASE ioctl Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2008-07-24UBI: fix checkpatch.pl errors and warningsArtem Bityutskiy
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>
2008-07-24UBI: fix and re-work debugging stuffArtem Bityutskiy
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-07-24UBI: fix error messageArtem Bityutskiy
The ubi_err() macro will add \n. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-04-17UBI: initialize static volumes with vol->used_bytesJan Altenberg
I came across a problem which seems to be present since: commit 941dfb07ed91451b1c58626a0d258dfdf468b593 UBI: set correct gluebi device size ubi_create_gluebi() leaves mtd->size = 0 for static volumes. So even existing static volumes are initialized with a size of 0. Signed-off-by: Jan Altenberg <jan.altenberg@linutronix.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26UBI: improve internal interfacesArtem Bityutskiy
Pass volume description object to the EBA function which makes more sense, and EBA function do not have to find the volume description object by volume ID. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18UBI: set correct gluebi device sizeArtem Bityutskiy
In case of static volumes, make emulated MTD device size to be equivalent to data size, rather then volume size. Reported-by: John Smith <john@arrows.demon.co.uk> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-04-27UBI: remove unused variableArtem Bityutskiy
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
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>