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# drivers/mtd/ubi/Kconfig
menu "UBI - Unsorted block images"
depends on MTD
config MTD_UBI
tristate "Enable UBI"
depends on MTD
select CRC32
help
UBI is a software layer above MTD layer which admits of LVM-like
logical volumes on top of MTD devices, hides some complexities of
flash chips like wear and bad blocks and provides some other useful
capabilities. Please, consult the MTD web site for more details
(www.linux-mtd.infradead.org).
config MTD_UBI_WL_THRESHOLD
int "UBI wear-leveling threshold"
default 4096
range 2 65536
depends on MTD_UBI
help
This parameter defines the maximum difference between the highest
erase counter value and the lowest erase counter value of eraseblocks
of UBI devices. When this threshold is exceeded, UBI starts performing
wear leveling by means of moving data from eraseblock with low erase
counter to eraseblocks with high erase counter.
The default value should be OK for SLC NAND flashes, NOR flashes and
other flashes which have eraseblock life-cycle 100000 or more.
However, in case of MLC NAND flashes which typically have eraseblock
life-cycle less then 10000, the threshold should be lessened (e.g.,
to 128 or 256, although it does not have to be power of 2).
config MTD_UBI_BEB_RESERVE
int "Percentage of reserved eraseblocks for bad eraseblocks handling"
default 1
range 0 25
depends on MTD_UBI
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.
config MTD_UBI_GLUEBI
bool "Emulate MTD devices"
default n
depends on MTD_UBI
help
This option enables MTD devices emulation on top of UBI volumes: for
each UBI volumes an MTD device is created, and all I/O to this MTD
device is redirected to the UBI volume. This is handy to make
MTD-oriented software (like JFFS2) work on top of UBI. Do not enable
this if no legacy software will be used.
source "drivers/mtd/ubi/Kconfig.debug"
endmenu
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