# 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 tristate "MTD devices emulation driver (gluebi)" default n depends on MTD_UBI 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. source "drivers/mtd/ubi/Kconfig.debug" endmenu