| 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 1 |
| 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. 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)" |
| 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 |
