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menuconfig MTD_UBI
tristate "Enable UBI - Unsorted block images"
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).
if MTD_UBI
config MTD_UBI_WL_THRESHOLD
int "UBI wear-leveling threshold"
default 4096
range 2 65536
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 than 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 2
range 0 25
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. 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)"
help
This option enables gluebi - an additional driver which emulates MTD
devices 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 unless you use legacy
software.
endif # MTD_UBI
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