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/openbmc/linux/include/linux/mtd/ |
H A D | mtd.h | 0e4ca7e5 Thu Dec 16 16:42:14 CST 2010 Anatolij Gustschin <agust@denx.de> mtd: add writebufsize field to mtd_info struct
This field will be used to indicate the write buffer size of the MTD device. UBI will set it's minimal I/O unit size (min_io_size) to the indicated write buffer size. By this change we intend to fix failed recovery of UBIFS partitions we currently observe on NOR flash when mounting the partition after unclean unmount.
Currently the min_io_size is set to mtd->writesize (which is 1 byte for NOR flash). But flash programming is often done from prepared write buffer containing multiple bytes and is performed in one programming operation which could be interrupted by a power cut or a system reset causing corrupted (partially written) areas in a flash sector. Knowing the size of potentially corrupted areas UBIFS scanning and recovery algorithms are able to perform successful recovery.
In case of NOR flash minimal I/O size must be equal to the maximal size of the write buffer used by embedded flash programming algorithm. In case of NAND flash mtd->writebufsize should be equivalent to mtd->writesize.
The subsequent patches will add mtd->writebufsize initialization where needed.
Signed-off-by: Anatolij Gustschin <agust@denx.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> 0e4ca7e5 Thu Dec 16 16:42:14 CST 2010 Anatolij Gustschin <agust@denx.de> mtd: add writebufsize field to mtd_info struct This field will be used to indicate the write buffer size of the MTD device. UBI will set it's minimal I/O unit size (min_io_size) to the indicated write buffer size. By this change we intend to fix failed recovery of UBIFS partitions we currently observe on NOR flash when mounting the partition after unclean unmount. Currently the min_io_size is set to mtd->writesize (which is 1 byte for NOR flash). But flash programming is often done from prepared write buffer containing multiple bytes and is performed in one programming operation which could be interrupted by a power cut or a system reset causing corrupted (partially written) areas in a flash sector. Knowing the size of potentially corrupted areas UBIFS scanning and recovery algorithms are able to perform successful recovery. In case of NOR flash minimal I/O size must be equal to the maximal size of the write buffer used by embedded flash programming algorithm. In case of NAND flash mtd->writebufsize should be equivalent to mtd->writesize. The subsequent patches will add mtd->writebufsize initialization where needed. Signed-off-by: Anatolij Gustschin <agust@denx.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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