1menu "UBI support"
2
3config UBI_SILENCE_MSG
4	bool "UBI silence verbose messages"
5	default ENV_IS_IN_UBI
6	help
7	  Make the verbose messages from UBI stop printing. This leaves
8	  warnings and errors enabled.
9
10config MTD_UBI
11	bool "Enable UBI - Unsorted block images"
12	select RBTREE
13	select MTD_PARTITIONS
14	help
15	  UBI is a software layer above MTD layer which admits of LVM-like
16	  logical volumes on top of MTD devices, hides some complexities of
17	  flash chips like wear and bad blocks and provides some other useful
18	  capabilities. Please, consult the MTD web site for more details
19	  (www.linux-mtd.infradead.org).
20
21if MTD_UBI
22
23config MTD_UBI_WL_THRESHOLD
24	int "UBI wear-leveling threshold"
25	default 4096
26	range 2 65536
27	help
28	  This parameter defines the maximum difference between the highest
29	  erase counter value and the lowest erase counter value of eraseblocks
30	  of UBI devices. When this threshold is exceeded, UBI starts performing
31	  wear leveling by means of moving data from eraseblock with low erase
32	  counter to eraseblocks with high erase counter.
33
34	  The default value should be OK for SLC NAND flashes, NOR flashes and
35	  other flashes which have eraseblock life-cycle 100000 or more.
36	  However, in case of MLC NAND flashes which typically have eraseblock
37	  life-cycle less than 10000, the threshold should be lessened (e.g.,
38	  to 128 or 256, although it does not have to be power of 2).
39
40config MTD_UBI_BEB_LIMIT
41	int "Maximum expected bad eraseblock count per 1024 eraseblocks"
42	default 20
43	range 0 768
44	help
45	  This option specifies the maximum bad physical eraseblocks UBI
46	  expects on the MTD device (per 1024 eraseblocks). If the underlying
47	  flash does not admit of bad eraseblocks (e.g. NOR flash), this value
48	  is ignored.
49
50	  NAND datasheets often specify the minimum and maximum NVM (Number of
51	  Valid Blocks) for the flashes' endurance lifetime. The maximum
52	  expected bad eraseblocks per 1024 eraseblocks then can be calculated
53	  as "1024 * (1 - MinNVB / MaxNVB)", which gives 20 for most NANDs
54	  (MaxNVB is basically the total count of eraseblocks on the chip).
55
56	  To put it differently, if this value is 20, UBI will try to reserve
57	  about 1.9% of physical eraseblocks for bad blocks handling. And that
58	  will be 1.9% of eraseblocks on the entire NAND chip, not just the MTD
59	  partition UBI attaches. This means that if you have, say, a NAND
60	  flash chip admits maximum 40 bad eraseblocks, and it is split on two
61	  MTD partitions of the same size, UBI will reserve 40 eraseblocks when
62	  attaching a partition.
63
64	  This option can be overridden by the "mtd=" UBI module parameter or
65	  by the "attach" ioctl.
66
67	  Leave the default value if unsure.
68
69config MTD_UBI_FASTMAP
70	bool "UBI Fastmap (Experimental feature)"
71	default n
72	help
73	   Important: this feature is experimental so far and the on-flash
74	   format for fastmap may change in the next kernel versions
75
76	   Fastmap is a mechanism which allows attaching an UBI device
77	   in nearly constant time. Instead of scanning the whole MTD device it
78	   only has to locate a checkpoint (called fastmap) on the device.
79	   The on-flash fastmap contains all information needed to attach
80	   the device. Using fastmap makes only sense on large devices where
81	   attaching by scanning takes long. UBI will not automatically install
82	   a fastmap on old images, but you can set the UBI module parameter
83	   fm_autoconvert to 1 if you want so. Please note that fastmap-enabled
84	   images are still usable with UBI implementations without
85	   fastmap support. On typical flash devices the whole fastmap fits
86	   into one PEB. UBI will reserve PEBs to hold two fastmaps.
87
88	   If in doubt, say "N".
89
90config MTD_UBI_FASTMAP_AUTOCONVERT
91	int "enable UBI Fastmap autoconvert"
92	depends on MTD_UBI_FASTMAP
93	default 0
94	help
95	  Set this parameter to enable fastmap automatically on images
96	  without a fastmap.
97
98config MTD_UBI_FM_DEBUG
99	int "Enable UBI fastmap debug"
100	depends on MTD_UBI_FASTMAP
101	default 0
102	help
103	  Enable UBI fastmap debug
104
105endif # MTD_UBI
106endmenu # "Enable UBI - Unsorted block images"
107