1# drivers/mtd/ubi/Kconfig 2 3menu "UBI - Unsorted block images" 4 depends on MTD 5 6config MTD_UBI 7 tristate "Enable UBI" 8 depends on MTD 9 select CRC32 10 help 11 UBI is a software layer above MTD layer which admits of LVM-like 12 logical volumes on top of MTD devices, hides some complexities of 13 flash chips like wear and bad blocks and provides some other useful 14 capabilities. Please, consult the MTD web site for more details 15 (www.linux-mtd.infradead.org). 16 17config MTD_UBI_WL_THRESHOLD 18 int "UBI wear-leveling threshold" 19 default 4096 20 range 2 65536 21 depends on MTD_UBI 22 help 23 This parameter defines the maximum difference between the highest 24 erase counter value and the lowest erase counter value of eraseblocks 25 of UBI devices. When this threshold is exceeded, UBI starts performing 26 wear leveling by means of moving data from eraseblock with low erase 27 counter to eraseblocks with high erase counter. 28 29 The default value should be OK for SLC NAND flashes, NOR flashes and 30 other flashes which have eraseblock life-cycle 100000 or more. 31 However, in case of MLC NAND flashes which typically have eraseblock 32 life-cycle less then 10000, the threshold should be lessened (e.g., 33 to 128 or 256, although it does not have to be power of 2). 34 35config MTD_UBI_BEB_RESERVE 36 int "Percentage of reserved eraseblocks for bad eraseblocks handling" 37 default 1 38 range 0 25 39 depends on MTD_UBI 40 help 41 If the MTD device admits of bad eraseblocks (e.g. NAND flash), UBI 42 reserves some amount of physical eraseblocks to handle new bad 43 eraseblocks. For example, if a flash physical eraseblock becomes bad, 44 UBI uses these reserved physical eraseblocks to relocate the bad one. 45 This option specifies how many physical eraseblocks will be reserved 46 for bad eraseblock handling (percents of total number of good flash 47 eraseblocks). If the underlying flash does not admit of bad 48 eraseblocks (e.g. NOR flash), this value is ignored and nothing is 49 reserved. Leave the default value if unsure. 50 51config MTD_UBI_GLUEBI 52 bool "Emulate MTD devices" 53 default n 54 depends on MTD_UBI 55 help 56 This option enables MTD devices emulation on top of UBI volumes: for 57 each UBI volumes an MTD device is created, and all I/O to this MTD 58 device is redirected to the UBI volume. This is handy to make 59 MTD-oriented software (like JFFS2) work on top of UBI. Do not enable 60 this if no legacy software will be used. 61 62source "drivers/mtd/ubi/Kconfig.debug" 63endmenu 64