[PATCH 1/5] ubi: introduce ubi->bad_peb_limit

Shmulik Ladkani
2012-07-04T08:06:00Z

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.

Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
---
arch/arm/configs/sam9_l9260_defconfig | 1 +
drivers/mtd/ubi/Kconfig | 11 +++++++++++
drivers/mtd/ubi/build.c | 13 ++++++++++++-
drivers/mtd/ubi/ubi.h | 2 ++
4 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/arch/arm/configs/sam9_l9260_defconfig b/arch/arm/configs/sam9_l9260_defconfig
index ecf2531..f6917c9 100644
--- a/arch/arm/configs/sam9_l9260_defconfig
+++ b/arch/arm/configs/sam9_l9260_defconfig
@@ -40,6 +40,7 @@ CONFIG_MTD_NAND_ATMEL=y
CONFIG_MTD_NAND_PLATFORM=y
CONFIG_MTD_UBI=y
CONFIG_MTD_UBI_BEB_RESERVE=3
+CONFIG_MTD_UBI_BEB_LIMIT=3
CONFIG_MTD_UBI_GLUEBI=y
CONFIG_BLK_DEV_LOOP=y
CONFIG_BLK_DEV_RAM=y
diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 738ee8d..8df256f 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -42,6 +42,17 @@ config MTD_UBI_BEB_RESERVE
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 eraseblocks UBI expects on the
+ ubi device (percents of total number of flash eraseblocks).
+ 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)"
help
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 2c5ed5c..62cc6ce 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -607,8 +607,19 @@ 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 beb_limit;
+
+ beb_limit = mult_frac(ubi->peb_count, percent, 100);
+ /* round it up */
+ if (mult_frac(beb_limit, 100, percent) < ubi->peb_count)
+ beb_limit++;
+ ubi->bad_peb_limit = beb_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 a1a81c9..b5217ef 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;
--
1.7.9