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path: root/drivers/mtd/ubi/io.c
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2008-07-24UBI: fix kernel-doc errors and warningsArtem Bityutskiy
No functional changes, just tweak comments to make kernel-doc work fine and stop complaining. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.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: rework scrubbing messagesArtem Bityutskiy
If bit-flips happen often, UBI prints to many messages. Lessen the amount by only printing the messages when the PEB has been scrubbed. Also, print torturing messages. 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: amend commentariesArtem Bityutskiy
Hch asked not to use "unit" for sub-systems, let it be so. Also some other commentaries modifications. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2008-04-17UBI: be verbose when debuggin is enabledArtem Bityutskiy
Make I/O function to be always verbose when about CRC errors and magic number errors when I/O debugging is enabled. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-12-26UBI: fix error code in ubi_io_read()Artem Bityutskiy
When NAND detects an ECC error, it returns -EBADMSG. It does not stop reading requested data if one page has an ECC error, it keeps going and reads all the requested data. If it fails to read all the data, it does not return -EBADMSG, but returns the error code which reflects the reason of the failure. But some drivers may have bugs (e.g., OneNAND had) and stop reading after the first ECC error, so it returns -EBADMSG. In turn, UBI propagates this up to the caller. The caller will treat this as "all the requested data was read, but there was an ECC error". So we change the error code to -EIO if it is -EBADMSG and the read length is less then the requested length. We also add an assertion, so if UBI debugging is enabled, UBI will bug. Pointed-to-by: Adrian Hunter <ext-adrian.hunter@nokia.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14UBI: use byte hexdumpArtem Bityutskiy
More handy since word hexdump prints in host endian. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14UBI: do not use vmalloc on I/O pathArtem Bityutskiy
Similar reason as in case of the previous patch: it causes deadlocks if a filesystem with writeback support works on top of UBI. So pre-allocate needed buffers when attaching MTD device. We also need mutexes to protect the buffers, but they do not cause much contantion because they are used in recovery, torture, and WL copy routines, which are called seldom. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14UBI: allocate memory with GFP_NOFSArtem Bityutskiy
Use GFP_NOFS flag when allocating memory on I/O path, because otherwise we may deadlock the filesystem which works on top of us. We observed the deadlocks with UBIFS. Example: VFS->FS lock a lock->UBI->kmalloc()->VFS writeback->FS locks the same lock again. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14UBI: use linux print_hex_dump(), not home-grown oneArtem Bityutskiy
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-10-14UBI: add more printsArtem Bityutskiy
I hit those situations and found out lack of print messages. Add more prints when erase problems occur. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18UBI: fix commentsArtem Bityutskiy
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18UBI: fix signed-unsigned multiplicationBrijesh Singh
There is signed multiplication assigned to unsigned ei.addr in io.c. This causes wrong addresses for big multiplication.This patch solves the problem. Signed-off-by: Brijesh Singh <brijesh.s.singh@gmail.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
2007-07-18UBI: kill homegrown endian macrosChristoph Hellwig
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>
2007-07-18UBI: use vmalloc for large buffersArtem Bityutskiy
UBI allocates temporary buffers of PEB size, which may be 256KiB. Use vmalloc instead of kmalloc for such big temporary buffers. 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>