From patchwork Fri Aug 17 14:57:20 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [2/4] sync include/mtd/ubi-user.h: add max_beb_per1024 parameter Date: Fri, 17 Aug 2012 04:57:20 -0000 From: Richard Genoud X-Patchwork-Id: 178235 Message-Id: <1345215442-19082-3-git-send-email-richard.genoud@gmail.com> To: Artem Bityutskiy Cc: Richard Genoud , linux-mtd@lists.infradead.org, Shmulik Ladkani , linux-kernel@vger.kernel.org Signed-off-by: Richard Genoud --- include/mtd/ubi-user.h | 19 ++++++++++++++++++- 1 files changed, 18 insertions(+), 1 deletions(-) diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h index 123951f..32771cf 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 bad eraseblocks per 1024 eraseblocks * @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 +246,28 @@ 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 bad eraseblocks 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 0-255. If 0 is given, the default kernel config value + * CONFIG_MTD_UBI_BEB_LIMIT will be used for compatibility. */ struct ubi_attach_req { __s32 ubi_num; __s32 mtd_num; __s32 vid_hdr_offset; - __s8 padding[12]; + __u8 max_beb_per1024; + __s8 padding[11]; }; /**