summaryrefslogtreecommitdiff
path: root/Documentation/ABI/testing/sysfs-class-mtd
blob: 43d18180b46ed54e32765af0fbb85a1e0819432e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
What:		/sys/class/mtd/
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		The mtd/ class subdirectory belongs to the MTD subsystem
		(MTD core).

What:		/sys/class/mtd/mtdX/
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		The /sys/class/mtd/mtd{0,1,2,3,...} directories correspond
		to each /dev/mtdX character device.  These may represent
		physical/simulated flash devices, partitions on a flash
		device, or concatenated flash devices.  They exist regardless
		of whether CONFIG_MTD_CHAR is actually enabled.

What:		/sys/class/mtd/mtdXro/
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		These directories provide the corresponding read-only device
		nodes for /sys/class/mtd/mtdX/ .  They are only created
		(for the benefit of udev) if CONFIG_MTD_CHAR is enabled.

What:		/sys/class/mtd/mtdX/dev
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		Major and minor numbers of the character device corresponding
		to this MTD device (in <major>:<minor> format).  This is the
		read-write device so <minor> will be even.

What:		/sys/class/mtd/mtdXro/dev
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		Major and minor numbers of the character device corresponding
		to the read-only variant of thie MTD device (in
		<major>:<minor> format).  In this case <minor> will be odd.

What:		/sys/class/mtd/mtdX/erasesize
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		"Major" erase size for the device.  If numeraseregions is
		zero, this is the eraseblock size for the entire device.
		Otherwise, the MEMGETREGIONCOUNT/MEMGETREGIONINFO ioctls
		can be used to determine the actual eraseblock layout.

What:		/sys/class/mtd/mtdX/flags
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		A hexadecimal value representing the device flags, ORed
		together:

		0x0400: MTD_WRITEABLE - device is writable
		0x0800: MTD_BIT_WRITEABLE - single bits can be flipped
		0x1000: MTD_NO_ERASE - no erase necessary
		0x2000: MTD_POWERUP_LOCK - always locked after reset

What:		/sys/class/mtd/mtdX/name
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		A human-readable ASCII name for the device or partition.
		This will match the name in /proc/mtd .

What:		/sys/class/mtd/mtdX/numeraseregions
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		For devices that have variable eraseblock sizes, this
		provides the total number of erase regions.  Otherwise,
		it will read back as zero.

What:		/sys/class/mtd/mtdX/oobsize
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		Number of OOB bytes per page.

What:		/sys/class/mtd/mtdX/size
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		Total size of the device/partition, in bytes.

What:		/sys/class/mtd/mtdX/type
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		One of the following ASCII strings, representing the device
		type:

		absent, ram, rom, nor, nand, dataflash, ubi, unknown

What:		/sys/class/mtd/mtdX/writesize
Date:		April 2009
KernelVersion:	2.6.29
Contact:	linux-mtd@lists.infradead.org
Description:
		Minimal writable flash unit size.  This will always be
		a positive integer.

		In the case of NOR flash it is 1 (even though individual
		bits can be cleared).

		In the case of NAND flash it is one NAND page (or a
		half page, or a quarter page).

		In the case of ECC NOR, it is the ECC block size.

What:		/sys/class/mtd/mtdX/ecc_strength
Date:		April 2012
KernelVersion:	3.4
Contact:	linux-mtd@lists.infradead.org
Description:
		Maximum number of bit errors that the device is capable of
		correcting within each region covering an ecc step.  This will
		always be a non-negative integer.  Note that some devices will
		have multiple ecc steps within each writesize region.

		In the case of devices lacking any ECC capability, it is 0.