54de1f1c44
The actual value (1%) is too low for actual NAND devices, a huge majority of device has 2% maximum bad blocks (SLC or MLC). (Actually it's 20 blocks on a 1024 blocks device, 40/2048...) Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
55 lines
2.3 KiB
Text
55 lines
2.3 KiB
Text
menuconfig MTD_UBI
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tristate "Enable UBI - Unsorted block images"
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select CRC32
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help
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UBI is a software layer above MTD layer which admits of LVM-like
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logical volumes on top of MTD devices, hides some complexities of
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flash chips like wear and bad blocks and provides some other useful
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capabilities. Please, consult the MTD web site for more details
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(www.linux-mtd.infradead.org).
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if MTD_UBI
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config MTD_UBI_WL_THRESHOLD
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int "UBI wear-leveling threshold"
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default 4096
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range 2 65536
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help
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This parameter defines the maximum difference between the highest
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erase counter value and the lowest erase counter value of eraseblocks
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of UBI devices. When this threshold is exceeded, UBI starts performing
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wear leveling by means of moving data from eraseblock with low erase
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counter to eraseblocks with high erase counter.
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The default value should be OK for SLC NAND flashes, NOR flashes and
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other flashes which have eraseblock life-cycle 100000 or more.
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However, in case of MLC NAND flashes which typically have eraseblock
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life-cycle less than 10000, the threshold should be lessened (e.g.,
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to 128 or 256, although it does not have to be power of 2).
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config MTD_UBI_BEB_RESERVE
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int "Percentage of reserved eraseblocks for bad eraseblocks handling"
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default 2
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range 0 25
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help
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If the MTD device admits of bad eraseblocks (e.g. NAND flash), UBI
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reserves some amount of physical eraseblocks to handle new bad
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eraseblocks. For example, if a flash physical eraseblock becomes bad,
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UBI uses these reserved physical eraseblocks to relocate the bad one.
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This option specifies how many physical eraseblocks will be reserved
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for bad eraseblock handling (percents of total number of good flash
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eraseblocks). If the underlying flash does not admit of bad
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eraseblocks (e.g. NOR flash), this value is ignored and nothing is
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reserved. Leave the default value if unsure.
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config MTD_UBI_GLUEBI
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tristate "MTD devices emulation driver (gluebi)"
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help
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This option enables gluebi - an additional driver which emulates MTD
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devices on top of UBI volumes: for each UBI volumes an MTD device is
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created, and all I/O to this MTD device is redirected to the UBI
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volume. This is handy to make MTD-oriented software (like JFFS2)
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work on top of UBI. Do not enable this unless you use legacy
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software.
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endif # MTD_UBI
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