How to configure the Linux kernel/Device drivers/Memory Technology Devices (MTD)/RAM-ROM-Flash chip drivers

Howto configure the Linux kernel / drivers / mtd / chips


 * drivers/mtd/chips]]
 * $Id: Kconfig,v 1.18 2005/11/07 11:14:22 gleixner Exp $

RAM/ROM/Flash chip drivers

 * depends on MTD!=n


 * Option: MTD_CFI
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Detect flash chips by Common Flash Interface (CFI) probe
 * depends on MTD
 * select MTD_GEN_PROBE
 * The Common Flash Interface specification was developed by Intel, AMD and other flash manufactures that provides a universal method for probing the capabilities of flash devices. If you wish to support any device that is CFI-compliant, you need to enable this option. Visit  for more information on CFI.


 * Option: MTD_JEDECPROBE
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Detect non-CFI AMD/JEDEC-compatible flash chips
 * depends on MTD
 * select MTD_GEN_PROBE
 * This option enables JEDEC-style probing of flash chips which are not compatible with the Common Flash Interface, but will use the common CFI-targeted flash drivers for any chips which are identified which are in fact compatible in all but the probe method. This actually covers most AMD/Fujitsu-compatible chips, and will shortly cover also non-CFI Intel chips (that code is in MTD CVS and should shortly be sent for inclusion in Linus' tree)


 * Option: MTD_GEN_PROBE
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module)


 * Option: MTD_CFI_ADV_OPTIONS
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Flash chip driver advanced configuration options
 * depends on MTD_GEN_PROBE
 * If you need to specify a specific endianness for access to flash chips, or if you wish to reduce the size of the kernel by including support for only specific arrangements of flash chips, say 'Y'. This option does not directly affect the code, but will enable other configuration options which allow you to do so.
 * If unsure, say 'N'.

"Flash cmd/query data swapping"
 * depends on MTD_CFI_ADV_OPTIONS
 * default MTD_CFI_NOSWAP


 * Option: MTD_CFI_NOSWAP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) NO
 * This option defines the way in which the CPU attempts to arrange data bits when writing the 'magic' commands to the chips. Saying 'NO', which is the default when CONFIG_MTD_CFI_ADV_OPTIONS isn't enabled, means that the CPU will not do any swapping; the chips are expected to be wired to the CPU in 'host-endian' form. Specific arrangements are possible with the BIG_ENDIAN_BYTE and LITTLE_ENDIAN_BYTE, if the bytes are reversed.
 * If you have a LART, on which the data (and address) lines were connected in a fashion which ensured that the nets were as short as possible, resulting in a bit-shuffling which seems utterly random to the untrained eye, you need the LART_ENDIAN_BYTE option.
 * Yes, there really exists something sicker than PDP-endian :)


 * Option: MTD_CFI_BE_BYTE_SWAP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) BIG_ENDIAN_BYTE


 * Option: MTD_CFI_LE_BYTE_SWAP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) LITTLE_ENDIAN_BYTE


 * Option: MTD_CFI_GEOMETRY
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Specific CFI Flash geometry selection
 * depends on MTD_CFI_ADV_OPTIONS
 * This option does not affect the code directly, but will enable some other configuration options which would allow you to reduce the size of the kernel by including support for only certain arrangements of CFI chips. If unsure, say 'N' and all options which are supported by the current code will be enabled.


 * Option: MTD_MAP_BANK_WIDTH_1
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support  8-bit buswidth if MTD_CFI_GEOMETRY
 * default y
 * If you wish to support CFI devices on a physical bus which is 8 bits wide, say 'Y'.


 * Option: MTD_MAP_BANK_WIDTH_2
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 16-bit buswidth if MTD_CFI_GEOMETRY
 * default y
 * If you wish to support CFI devices on a physical bus which is 16 bits wide, say 'Y'.


 * Option: MTD_MAP_BANK_WIDTH_4
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 32-bit buswidth if MTD_CFI_GEOMETRY
 * default y
 * If you wish to support CFI devices on a physical bus which is 32 bits wide, say 'Y'.


 * Option: MTD_MAP_BANK_WIDTH_8
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 64-bit buswidth if MTD_CFI_GEOMETRY
 * default n
 * If you wish to support CFI devices on a physical bus which is 64 bits wide, say 'Y'.


 * Option: MTD_MAP_BANK_WIDTH_16
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 128-bit buswidth if MTD_CFI_GEOMETRY
 * default n
 * If you wish to support CFI devices on a physical bus which is 128 bits wide, say 'Y'.


 * Option: MTD_MAP_BANK_WIDTH_32
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 256-bit buswidth if MTD_CFI_GEOMETRY
 * default n
 * If you wish to support CFI devices on a physical bus which is 256 bits wide, say 'Y'.


 * Option: MTD_CFI_I1
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 1-chip flash interleave if MTD_CFI_GEOMETRY
 * default y
 * If your flash chips are not interleaved - i.e. you only have one flash chip addressed by each bus cycle, then say 'Y'.


 * Option: MTD_CFI_I2
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 2-chip flash interleave if MTD_CFI_GEOMETRY
 * default y
 * If your flash chips are interleaved in pairs - i.e. you have two flash chips addressed by each bus cycle, then say 'Y'.


 * Option: MTD_CFI_I4
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 4-chip flash interleave if MTD_CFI_GEOMETRY
 * default n
 * If your flash chips are interleaved in fours - i.e. you have four flash chips addressed by each bus cycle, then say 'Y'.


 * Option: MTD_CFI_I8
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Support 8-chip flash interleave if MTD_CFI_GEOMETRY
 * default n
 * If your flash chips are interleaved in eights - i.e. you have eight flash chips addressed by each bus cycle, then say 'Y'.


 * Option: MTD_OTP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) Protection Registers aka one-time programmable (OTP) bits
 * depends on MTD_CFI_ADV_OPTIONS
 * default n
 * This enables support for reading, writing and locking so called Protection Registers present on some flash chips. A subset of them are pre-programmed at the factory with a unique set of values. The rest is user-programmable.
 * The user-programmable Protection Registers contain one-time programmable (OTP) bits; when programmed, register bits cannot be erased. Each Protection Register can be accessed multiple times to program individual bits, as long as the register remains unlocked.
 * Each Protection Register has an associated Lock Register bit. When a Lock Register bit is programmed, the associated Protection Register can only be read; it can no longer be programmed. Additionally, because the Lock Register bits themselves are OTP, when programmed, Lock Register bits cannot be erased. Therefore, when a Protection Register is locked, it cannot be unlocked.
 * This feature should therefore be used with extreme care. Any mistake in the programming of OTP bits will waste them.


 * Option: MTD_CFI_INTELEXT
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for Intel/Sharp flash chips
 * depends on MTD_GEN_PROBE
 * select MTD_CFI_UTIL
 * The Common Flash Interface defines a number of different command sets which a CFI-compliant chip may claim to implement. This code provides support for one of those command sets, used on Intel StrataFlash and other parts.


 * Option: MTD_CFI_AMDSTD
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for AMD/Fujitsu flash chips
 * depends on MTD_GEN_PROBE
 * select MTD_CFI_UTIL
 * The Common Flash Interface defines a number of different command sets which a CFI-compliant chip may claim to implement. This code provides support for one of those command sets, used on chips including the AMD Am29LV320.

"Retry failed commands (erase/program)"
 * Option: MTD_CFI_AMDSTD_RETRY
 * Kernel Versions: 2.6.15.6 ...
 * depends on MTD_CFI_AMDSTD
 * default "0"
 * Some chips, when attached to a shared bus, don't properly filter bus traffic that is destined to other devices. This broken behavior causes erase and program sequences to be aborted when the sequences are mixed with traffic for other devices.
 * SST49LF040 (and related) chips are know to be broken.

"Max retries of failed commands (erase/program)"
 * Option: MTD_CFI_AMDSTD_RETRY_MAX
 * Kernel Versions: 2.6.15.6 ...
 * depends on MTD_CFI_AMDSTD_RETRY
 * default "0"
 * If you have an SST49LF040 (or related chip) then this value should be set to at least 1. This can also be adjusted at driver load time with the retry_cmd_max module parameter.


 * Option: MTD_CFI_STAA
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for ST (Advanced Architecture) flash chips
 * depends on MTD_GEN_PROBE
 * select MTD_CFI_UTIL
 * The Common Flash Interface defines a number of different command sets which a CFI-compliant chip may claim to implement. This code provides support for one of those command sets.


 * Option: MTD_CFI_UTIL
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module)


 * Option: MTD_RAM
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for RAM chips in bus mapping
 * depends on MTD
 * This option enables basic support for RAM chips accessed through a bus mapping driver.


 * Option: MTD_ROM
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for ROM chips in bus mapping
 * depends on MTD
 * This option enables basic support for ROM chips accessed through a bus mapping driver.


 * Option: MTD_ABSENT
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) Support for absent chips in bus mapping
 * depends on MTD
 * This option enables support for a dummy probing driver used to allocated placeholder MTD devices on systems that have socketed or removable media. Use of this driver as a fallback chip probe preserves the expected registration order of MTD device nodes on the system regardless of media presence.  Device nodes created with this driver will return -ENODEV upon access.


 * Option: MTD_OBSOLETE_CHIPS
 * Kernel Versions: 2.6.15.6 ...
 * depends on MTD && BROKEN
 * (on/off) Older (theoretically obsoleted now) drivers for non-CFI chips
 * This option does not enable any code directly, but will allow you to select some other chip drivers which are now considered obsolete, because the generic CONFIG_JEDECPROBE code above should now detect the chips which are supported by these drivers, and allow the generic CFI-compatible drivers to drive the chips. Say 'N' here unless you have already tried the CONFIG_JEDECPROBE method and reported its failure to the MTD mailing list at 


 * Option: MTD_AMDSTD
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) AMD compatible flash chip support (non-CFI)
 * depends on MTD && MTD_OBSOLETE_CHIPS
 * This option enables support for flash chips using AMD-compatible commands, including some which are not CFI-compatible and hence cannot be used with the CONFIG_MTD_CFI_AMDSTD option.
 * It also works on AMD compatible chips that do conform to CFI.


 * Option: MTD_SHARP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) pre-CFI Sharp chip support
 * depends on MTD && MTD_OBSOLETE_CHIPS
 * This option enables support for flash chips using Sharp-compatible commands, including some which are not CFI-compatible and hence cannot be used with the CONFIG_MTD_CFI_INTELxxx options.


 * Option: MTD_JEDEC
 * Kernel Versions: 2.6.15.6 ...
 * (on/off/module) JEDEC device support
 * depends on MTD && MTD_OBSOLETE_CHIPS
 * Enable older older JEDEC flash interface devices for self programming flash. It is commonly used in older AMD chips.  It is only called JEDEC because the JEDEC association  distributes the identification codes for the chips.


 * Option: MTD_XIP
 * Kernel Versions: 2.6.15.6 ...
 * (on/off) XIP aware MTD support
 * depends on !SMP && (MTD_CFI_INTELEXT || MTD_CFI_AMDSTD) && EXPERIMENTAL && ARM
 * default y if XIP_KERNEL
 * This allows MTD support to work with flash memory which is also used for XIP purposes. If you're not sure what this is all about then say N.

Linux Kernel Configuration