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Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-mtd')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-mtd | 176 |
1 files changed, 0 insertions, 176 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-mtd b/Documentation/ABI/testing/sysfs-class-mtd deleted file mode 100644 index db1ad7e34fc..00000000000 --- a/Documentation/ABI/testing/sysfs-class-mtd +++ /dev/null @@ -1,176 +0,0 @@ -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. - -What: /sys/class/mtd/mtdX/bitflip_threshold -Date: April 2012 -KernelVersion: 3.4 -Contact: linux-mtd@lists.infradead.org -Description: - This allows the user to examine and adjust the criteria by which - mtd returns -EUCLEAN from mtd_read(). If the maximum number of - bit errors that were corrected on any single region comprising - an ecc step (as reported by the driver) equals or exceeds this - value, -EUCLEAN is returned. Otherwise, absent an error, 0 is - returned. Higher layers (e.g., UBI) use this return code as an - indication that an erase block may be degrading and should be - scrutinized as a candidate for being marked as bad. - - The initial value may be specified by the flash device driver. - If not, then the default value is ecc_strength. - - The introduction of this feature brings a subtle change to the - meaning of the -EUCLEAN return code. Previously, it was - interpreted to mean simply "one or more bit errors were - corrected". Its new interpretation can be phrased as "a - dangerously high number of bit errors were corrected on one or - more regions comprising an ecc step". The precise definition of - "dangerously high" can be adjusted by the user with - bitflip_threshold. Users are discouraged from doing this, - however, unless they know what they are doing and have intimate - knowledge of the properties of their device. Broadly speaking, - bitflip_threshold should be low enough to detect genuine erase - block degradation, but high enough to avoid the consequences of - a persistent return value of -EUCLEAN on devices where sticky - bitflips occur. Note that if bitflip_threshold exceeds - ecc_strength, -EUCLEAN is never returned by mtd_read(). - Conversely, if bitflip_threshold is zero, -EUCLEAN is always - returned, absent a hard error. - - This is generally applicable only to NAND flash devices with ECC - capability. It is ignored on devices lacking ECC capability; - i.e., devices for which ecc_strength is zero. |