From 8beeb3bb9df8caba36ad3e4f226255dff9c92556 Mon Sep 17 00:00:00 2001 From: Shmulik Ladkani Date: Wed, 4 Jul 2012 11:06:00 +0300 Subject: [PATCH] UBI: introduce new bad PEB limit Introduce 'ubi->bad_peb_limit', which specifies an upper limit of PEBs UBI expects to go bad. Currently, it is initialized to a fixed percentage of total PEBs in the UBI device (configurable via CONFIG_MTD_UBI_BEB_LIMIT). The 'bad_peb_limit' is intended to be used for calculating the amount of PEBs UBI needs to reserve for bad eraseblock handling. Artem: minor amendments. Signed-off-by: Shmulik Ladkani Signed-off-by: Artem Bityutskiy --- drivers/mtd/ubi/Kconfig | 26 +++++++++++++++++++------- drivers/mtd/ubi/build.c | 12 +++++++++++- drivers/mtd/ubi/ubi.h | 2 ++ 3 files changed, 32 insertions(+), 8 deletions(-) diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig index ea4b95b5451c..76195ac90e51 100644 --- a/drivers/mtd/ubi/Kconfig +++ b/drivers/mtd/ubi/Kconfig @@ -34,13 +34,25 @@ config MTD_UBI_BEB_RESERVE help If the MTD device admits of bad eraseblocks (e.g. NAND flash), UBI reserves some amount of physical eraseblocks to handle new bad - eraseblocks. For example, if a flash physical eraseblock becomes bad, - UBI uses these reserved physical eraseblocks to relocate the bad one. - This option specifies how many physical eraseblocks will be reserved - for bad eraseblock handling (percents of total number of good flash - eraseblocks). If the underlying flash does not admit of bad - eraseblocks (e.g. NOR flash), this value is ignored and nothing is - reserved. Leave the default value if unsure. + eraseblocks. When a physical eraseblock becomes bad, UBI uses these + reserved physical eraseblocks to relocate the bad one. This + configuration option specifies how many physical eraseblocks will be + reserved for bad eraseblock handling (percents of total number of + good physical eraseblocks on this MTD partition). If the underlying + flash does not admit of bad eraseblocks (e.g. NOR flash), this value + is ignored and nothing is reserved. Leave the default value if + unsure. + +config MTD_UBI_BEB_LIMIT + int "Percentage of maximum expected bad eraseblocks" + default 2 + range 0 25 + help + This option specifies the maximum bad physical eraseblocks UBI + expects on the UBI device (percents of total number of physical + eraseblocks on this MTD partition). If the underlying flash does not + admit of bad eraseblocks (e.g. NOR flash), this value is ignored. + Leave the default value if unsure. config MTD_UBI_GLUEBI tristate "MTD devices emulation driver (gluebi)" diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c index 3174dd40095d..ce311aa75a75 100644 --- a/drivers/mtd/ubi/build.c +++ b/drivers/mtd/ubi/build.c @@ -607,8 +607,18 @@ static int io_init(struct ubi_device *ubi) ubi->peb_count = mtd_div_by_eb(ubi->mtd->size, ubi->mtd); ubi->flash_size = ubi->mtd->size; - if (mtd_can_have_bb(ubi->mtd)) + if (mtd_can_have_bb(ubi->mtd)) { ubi->bad_allowed = 1; + if (CONFIG_MTD_UBI_BEB_LIMIT > 0) { + int percent = CONFIG_MTD_UBI_BEB_LIMIT; + int limit = mult_frac(ubi->peb_count, percent, 100); + + /* Round it up */ + if (mult_frac(limit, 100, percent) < ubi->peb_count) + limit += 1; + ubi->bad_peb_limit = limit; + } + } if (ubi->mtd->type == MTD_NORFLASH) { ubi_assert(ubi->mtd->writesize == 1); diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h index 84f66e3fa05d..aeb459eb7e42 100644 --- a/drivers/mtd/ubi/ubi.h +++ b/drivers/mtd/ubi/ubi.h @@ -363,6 +363,7 @@ struct ubi_wl_entry; * @flash_size: underlying MTD device size (in bytes) * @peb_count: count of physical eraseblocks on the MTD device * @peb_size: physical eraseblock size + * @bad_peb_limit: top limit of expected bad physical eraseblocks * @bad_peb_count: count of bad physical eraseblocks * @good_peb_count: count of good physical eraseblocks * @corr_peb_count: count of corrupted physical eraseblocks (preserved and not @@ -410,6 +411,7 @@ struct ubi_device { int avail_pebs; int beb_rsvd_pebs; int beb_rsvd_level; + int bad_peb_limit; int autoresize_vol_id; int vtbl_slots;