| Artem B. Bityutskiy | 801c135 | 2006-06-27 12:22:22 +0400 | [diff] [blame] | 1 | # drivers/mtd/ubi/Kconfig |
| 2 | |
| 3 | menu "UBI - Unsorted block images" |
| 4 | depends on MTD |
| 5 | |
| 6 | config 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 | |
| 17 | config 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 |
| Artem Bityutskiy | 6e0c84e | 2008-03-27 17:18:45 +0200 | [diff] [blame^] | 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). |
| Artem B. Bityutskiy | 801c135 | 2006-06-27 12:22:22 +0400 | [diff] [blame] | 34 | |
| 35 | config 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 | |
| 51 | config 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 | |
| 62 | source "drivers/mtd/ubi/Kconfig.debug" |
| 63 | endmenu |