From db7e21c21f293d52f5363fe8d9ee91d6bd0a503a Mon Sep 17 00:00:00 2001 From: Richard Genoud Date: Mon, 20 Aug 2012 18:00:15 +0200 Subject: UBI: add max_beb_per1024 to attach ioctl 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 Signed-off-by: Artem Bityutskiy --- include/mtd/ubi-user.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'include/mtd') diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h index 8787349..53cae1e 100644 --- a/include/mtd/ubi-user.h +++ b/include/mtd/ubi-user.h @@ -222,6 +222,7 @@ enum { * @ubi_num: UBI device number to create * @mtd_num: MTD device number to attach * @vid_hdr_offset: VID header offset (use defaults if %0) + * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs * @padding: reserved for future, not used, has to be zeroed * * This data structure is used to specify MTD device UBI has to attach and the @@ -245,12 +246,25 @@ enum { * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes * aligned, which is OK, as UBI is clever enough to realize this is 4th * sub-page of the first page and add needed padding. + * + * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the + * UBI device per 1024 eraseblocks. This value is often given in an other form + * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The + * maximum expected bad eraseblocks per 1024 is then: + * 1024 * (1 - MinNVB / MaxNVB) + * Which gives 20 for most NAND devices. This limit is used in order to derive + * amount of eraseblock UBI reserves for handling new bad blocks. If the device + * has more bad eraseblocks than this limit, UBI does not reserve any physical + * eraseblocks for new bad eraseblocks, but attempts to use available + * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the + * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used. */ struct ubi_attach_req { __s32 ubi_num; __s32 mtd_num; __s32 vid_hdr_offset; - __s8 padding[12]; + __s16 max_beb_per1024; + __s8 padding[10]; }; /** -- cgit v1.1