Documentation/ABI/testing/sysfs-class-mtd

   1 What:           /sys/class/mtd/
   2 Date:           April 2009
   3 KernelVersion:  2.6.29
   4 Contact:        linux-mtd@lists.infradead.org
   5 Description:
   6                 The mtd/ class subdirectory belongs to the MTD subsystem
   7                 (MTD core).
   8
   9 What:           /sys/class/mtd/mtdX/
  10 Date:           April 2009
  11 KernelVersion:  2.6.29
  12 Contact:        linux-mtd@lists.infradead.org
  13 Description:
  14                 The /sys/class/mtd/mtd{0,1,2,3,...} directories correspond
  15                 to each /dev/mtdX character device.  These may represent
  16                 physical/simulated flash devices, partitions on a flash
  17                 device, or concatenated flash devices.  They exist regardless
  18                 of whether CONFIG_MTD_CHAR is actually enabled.
  19
  20 What:           /sys/class/mtd/mtdXro/
  21 Date:           April 2009
  22 KernelVersion:  2.6.29
  23 Contact:        linux-mtd@lists.infradead.org
  24 Description:
  25                 These directories provide the corresponding read-only device
  26                 nodes for /sys/class/mtd/mtdX/ .  They are only created
  27                 (for the benefit of udev) if CONFIG_MTD_CHAR is enabled.
  28
  29 What:           /sys/class/mtd/mtdX/dev
  30 Date:           April 2009
  31 KernelVersion:  2.6.29
  32 Contact:        linux-mtd@lists.infradead.org
  33 Description:
  34                 Major and minor numbers of the character device corresponding
  35                 to this MTD device (in <major>:<minor> format).  This is the
  36                 read-write device so <minor> will be even.
  37
  38 What:           /sys/class/mtd/mtdXro/dev
  39 Date:           April 2009
  40 KernelVersion:  2.6.29
  41 Contact:        linux-mtd@lists.infradead.org
  42 Description:
  43                 Major and minor numbers of the character device corresponding
  44                 to the read-only variant of thie MTD device (in
  45                 <major>:<minor> format).  In this case <minor> will be odd.
  46
  47 What:           /sys/class/mtd/mtdX/erasesize
  48 Date:           April 2009
  49 KernelVersion:  2.6.29
  50 Contact:        linux-mtd@lists.infradead.org
  51 Description:
  52                 "Major" erase size for the device.  If numeraseregions is
  53                 zero, this is the eraseblock size for the entire device.
  54                 Otherwise, the MEMGETREGIONCOUNT/MEMGETREGIONINFO ioctls
  55                 can be used to determine the actual eraseblock layout.
  56
  57 What:           /sys/class/mtd/mtdX/flags
  58 Date:           April 2009
  59 KernelVersion:  2.6.29
  60 Contact:        linux-mtd@lists.infradead.org
  61 Description:
  62                 A hexadecimal value representing the device flags, ORed
  63                 together:
  64
  65                 0x0400: MTD_WRITEABLE - device is writable
  66                 0x0800: MTD_BIT_WRITEABLE - single bits can be flipped
  67                 0x1000: MTD_NO_ERASE - no erase necessary
  68                 0x2000: MTD_POWERUP_LOCK - always locked after reset
  69
  70 What:           /sys/class/mtd/mtdX/name
  71 Date:           April 2009
  72 KernelVersion:  2.6.29
  73 Contact:        linux-mtd@lists.infradead.org
  74 Description:
  75                 A human-readable ASCII name for the device or partition.
  76                 This will match the name in /proc/mtd .
  77
  78 What:           /sys/class/mtd/mtdX/numeraseregions
  79 Date:           April 2009
  80 KernelVersion:  2.6.29
  81 Contact:        linux-mtd@lists.infradead.org
  82 Description:
  83                 For devices that have variable eraseblock sizes, this
  84                 provides the total number of erase regions.  Otherwise,
  85                 it will read back as zero.
  86
  87 What:           /sys/class/mtd/mtdX/oobsize
  88 Date:           April 2009
  89 KernelVersion:  2.6.29
  90 Contact:        linux-mtd@lists.infradead.org
  91 Description:
  92                 Number of OOB bytes per page.
  93
  94 What:           /sys/class/mtd/mtdX/size
  95 Date:           April 2009
  96 KernelVersion:  2.6.29
  97 Contact:        linux-mtd@lists.infradead.org
  98 Description:
  99                 Total size of the device/partition, in bytes.
 100
 101 What:           /sys/class/mtd/mtdX/type
 102 Date:           April 2009
 103 KernelVersion:  2.6.29
 104 Contact:        linux-mtd@lists.infradead.org
 105 Description:
 106                 One of the following ASCII strings, representing the device
 107                 type:
 108
 109                 absent, ram, rom, nor, nand, dataflash, ubi, unknown
 110
 111 What:           /sys/class/mtd/mtdX/writesize
 112 Date:           April 2009
 113 KernelVersion:  2.6.29
 114 Contact:        linux-mtd@lists.infradead.org
 115 Description:
 116                 Minimal writable flash unit size.  This will always be
 117                 a positive integer.
 118
 119                 In the case of NOR flash it is 1 (even though individual
 120                 bits can be cleared).
 121
 122                 In the case of NAND flash it is one NAND page (or a
 123                 half page, or a quarter page).
 124
 125                 In the case of ECC NOR, it is the ECC block size.
 126
 127 What:           /sys/class/mtd/mtdX/ecc_strength
 128 Date:           April 2012
 129 KernelVersion:  3.4
 130 Contact:        linux-mtd@lists.infradead.org
 131 Description:
 132                 Maximum number of bit errors that the device is capable of
 133                 correcting within each region covering an ecc step.  This will
 134                 always be a non-negative integer.  Note that some devices will
 135                 have multiple ecc steps within each writesize region.
 136
 137                 In the case of devices lacking any ECC capability, it is 0.