Kconfig 4.0 KB

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  1. menu "UBI support"
  2. config UBI_SILENCE_MSG
  3. bool "UBI silence verbose messages"
  4. default ENV_IS_IN_UBI
  5. help
  6. Make the verbose messages from UBI stop printing. This leaves
  7. warnings and errors enabled.
  8. config MTD_UBI
  9. bool "Enable UBI - Unsorted block images"
  10. select RBTREE
  11. select MTD_PARTITIONS
  12. help
  13. UBI is a software layer above MTD layer which admits of LVM-like
  14. logical volumes on top of MTD devices, hides some complexities of
  15. flash chips like wear and bad blocks and provides some other useful
  16. capabilities. Please, consult the MTD web site for more details
  17. (www.linux-mtd.infradead.org).
  18. if MTD_UBI
  19. config MTD_UBI_WL_THRESHOLD
  20. int "UBI wear-leveling threshold"
  21. default 4096
  22. range 2 65536
  23. help
  24. This parameter defines the maximum difference between the highest
  25. erase counter value and the lowest erase counter value of eraseblocks
  26. of UBI devices. When this threshold is exceeded, UBI starts performing
  27. wear leveling by means of moving data from eraseblock with low erase
  28. counter to eraseblocks with high erase counter.
  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 than 10000, the threshold should be lessened (e.g.,
  33. to 128 or 256, although it does not have to be power of 2).
  34. config MTD_UBI_BEB_LIMIT
  35. int "Maximum expected bad eraseblock count per 1024 eraseblocks"
  36. default 20
  37. range 0 768
  38. help
  39. This option specifies the maximum bad physical eraseblocks UBI
  40. expects on the MTD device (per 1024 eraseblocks). If the underlying
  41. flash does not admit of bad eraseblocks (e.g. NOR flash), this value
  42. is ignored.
  43. NAND datasheets often specify the minimum and maximum NVM (Number of
  44. Valid Blocks) for the flashes' endurance lifetime. The maximum
  45. expected bad eraseblocks per 1024 eraseblocks then can be calculated
  46. as "1024 * (1 - MinNVB / MaxNVB)", which gives 20 for most NANDs
  47. (MaxNVB is basically the total count of eraseblocks on the chip).
  48. To put it differently, if this value is 20, UBI will try to reserve
  49. about 1.9% of physical eraseblocks for bad blocks handling. And that
  50. will be 1.9% of eraseblocks on the entire NAND chip, not just the MTD
  51. partition UBI attaches. This means that if you have, say, a NAND
  52. flash chip admits maximum 40 bad eraseblocks, and it is split on two
  53. MTD partitions of the same size, UBI will reserve 40 eraseblocks when
  54. attaching a partition.
  55. This option can be overridden by the "mtd=" UBI module parameter or
  56. by the "attach" ioctl.
  57. Leave the default value if unsure.
  58. config MTD_UBI_FASTMAP
  59. bool "UBI Fastmap (Experimental feature)"
  60. default n
  61. help
  62. Important: this feature is experimental so far and the on-flash
  63. format for fastmap may change in the next kernel versions
  64. Fastmap is a mechanism which allows attaching an UBI device
  65. in nearly constant time. Instead of scanning the whole MTD device it
  66. only has to locate a checkpoint (called fastmap) on the device.
  67. The on-flash fastmap contains all information needed to attach
  68. the device. Using fastmap makes only sense on large devices where
  69. attaching by scanning takes long. UBI will not automatically install
  70. a fastmap on old images, but you can set the UBI module parameter
  71. fm_autoconvert to 1 if you want so. Please note that fastmap-enabled
  72. images are still usable with UBI implementations without
  73. fastmap support. On typical flash devices the whole fastmap fits
  74. into one PEB. UBI will reserve PEBs to hold two fastmaps.
  75. If in doubt, say "N".
  76. config MTD_UBI_FASTMAP_AUTOCONVERT
  77. int "enable UBI Fastmap autoconvert"
  78. depends on MTD_UBI_FASTMAP
  79. default 0
  80. help
  81. Set this parameter to enable fastmap automatically on images
  82. without a fastmap.
  83. config MTD_UBI_FM_DEBUG
  84. int "Enable UBI fastmap debug"
  85. depends on MTD_UBI_FASTMAP
  86. default 0
  87. help
  88. Enable UBI fastmap debug
  89. endif # MTD_UBI
  90. endmenu # "Enable UBI - Unsorted block images"