linux/drivers/mtd/Kconfig
WeiXiong Liao 78c08247b9 mtd: Support kmsg dumper based on pstore/blk
This introduces mtdpstore, which is similar to mtdoops but more
powerful. It uses pstore/blk, and aims to store panic and oops logs to
a flash partition, where pstore can later read back and present as files
in the mounted pstore filesystem.

To make mtdpstore work, the "blkdev" of pstore/blk should be set
as MTD device name or MTD device number. For more details, see
Documentation/admin-guide/pstore-blk.rst

This solves a number of issues:
- Work duplication: both of pstore and mtdoops do the same job storing
  panic/oops log. They have very similar logic, registering to kmsg
  dumper and storing logs to several chunks one by one.
- Layer violations: drivers should provides methods instead of polices.
  MTD should provide read/write/erase operations, and allow a higher
  level drivers to provide the chunk management, kmsg dump
  configuration, etc.
- Missing features: pstore provides many additional features, including
  presenting the logs as files, logging dump time and count, and
  supporting other frontends like pmsg, console, etc.

Signed-off-by: WeiXiong Liao <liaoweixiong@allwinnertech.com>
Link: https://lore.kernel.org/lkml/20200511233229.27745-11-keescook@chromium.org/
Link: https://lore.kernel.org/r/1589266715-4168-1-git-send-email-liaoweixiong@allwinnertech.com
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-05-31 19:49:01 -07:00

223 lines
7.6 KiB
Plaintext

menuconfig MTD
tristate "Memory Technology Device (MTD) support"
imply NVMEM
help
Memory Technology Devices are flash, RAM and similar chips, often
used for solid state file systems on embedded devices. This option
will provide the generic support for MTD drivers to register
themselves with the kernel and for potential users of MTD devices
to enumerate the devices which are present and obtain a handle on
them. It will also allow you to select individual drivers for
particular hardware and users of MTD devices. If unsure, say N.
if MTD
config MTD_TESTS
tristate "MTD tests support (DANGEROUS)"
depends on m
help
This option includes various MTD tests into compilation. The tests
should normally be compiled as kernel modules. The modules perform
various checks and verifications when loaded.
WARNING: some of the tests will ERASE entire MTD device which they
test. Do not use these tests unless you really know what you do.
menu "Partition parsers"
source "drivers/mtd/parsers/Kconfig"
endmenu
comment "User Modules And Translation Layers"
#
# MTD block device support is select'ed if needed
#
config MTD_BLKDEVS
tristate
config MTD_BLOCK
tristate "Caching block device access to MTD devices"
depends on BLOCK
select MTD_BLKDEVS
help
Although most flash chips have an erase size too large to be useful
as block devices, it is possible to use MTD devices which are based
on RAM chips in this manner. This block device is a user of MTD
devices performing that function.
At the moment, it is also required for the Journalling Flash File
System(s) to obtain a handle on the MTD device when it's mounted
(although JFFS and JFFS2 don't actually use any of the functionality
of the mtdblock device).
Later, it may be extended to perform read/erase/modify/write cycles
on flash chips to emulate a smaller block size. Needless to say,
this is very unsafe, but could be useful for file systems which are
almost never written to.
You do not need this option for use with the DiskOnChip devices. For
those, enable NFTL support (CONFIG_NFTL) instead.
config MTD_BLOCK_RO
tristate "Readonly block device access to MTD devices"
depends on MTD_BLOCK!=y && BLOCK
select MTD_BLKDEVS
help
This allows you to mount read-only file systems (such as cramfs)
from an MTD device, without the overhead (and danger) of the caching
driver.
You do not need this option for use with the DiskOnChip devices. For
those, enable NFTL support (CONFIG_NFTL) instead.
config FTL
tristate "FTL (Flash Translation Layer) support"
depends on BLOCK
select MTD_BLKDEVS
help
This provides support for the original Flash Translation Layer which
is part of the PCMCIA specification. It uses a kind of pseudo-
file system on a flash device to emulate a block device with
512-byte sectors, on top of which you put a 'normal' file system.
You may find that the algorithms used in this code are patented
unless you live in the Free World where software patents aren't
legal - in the USA you are only permitted to use this on PCMCIA
hardware, although under the terms of the GPL you're obviously
permitted to copy, modify and distribute the code as you wish. Just
not use it.
config NFTL
tristate "NFTL (NAND Flash Translation Layer) support"
depends on BLOCK
select MTD_BLKDEVS
help
This provides support for the NAND Flash Translation Layer which is
used on M-Systems' DiskOnChip devices. It uses a kind of pseudo-
file system on a flash device to emulate a block device with
512-byte sectors, on top of which you put a 'normal' file system.
You may find that the algorithms used in this code are patented
unless you live in the Free World where software patents aren't
legal - in the USA you are only permitted to use this on DiskOnChip
hardware, although under the terms of the GPL you're obviously
permitted to copy, modify and distribute the code as you wish. Just
not use it.
config NFTL_RW
bool "Write support for NFTL"
depends on NFTL
help
Support for writing to the NAND Flash Translation Layer, as used
on the DiskOnChip.
config INFTL
tristate "INFTL (Inverse NAND Flash Translation Layer) support"
depends on BLOCK
select MTD_BLKDEVS
help
This provides support for the Inverse NAND Flash Translation
Layer which is used on M-Systems' newer DiskOnChip devices. It
uses a kind of pseudo-file system on a flash device to emulate
a block device with 512-byte sectors, on top of which you put
a 'normal' file system.
You may find that the algorithms used in this code are patented
unless you live in the Free World where software patents aren't
legal - in the USA you are only permitted to use this on DiskOnChip
hardware, although under the terms of the GPL you're obviously
permitted to copy, modify and distribute the code as you wish. Just
not use it.
config RFD_FTL
tristate "Resident Flash Disk (Flash Translation Layer) support"
depends on BLOCK
select MTD_BLKDEVS
help
This provides support for the flash translation layer known
as the Resident Flash Disk (RFD), as used by the Embedded BIOS
of General Software. There is a blurb at:
http://www.gensw.com/pages/prod/bios/rfd.htm
config SSFDC
tristate "NAND SSFDC (SmartMedia) read only translation layer"
depends on BLOCK
select MTD_BLKDEVS
help
This enables read only access to SmartMedia formatted NAND
flash. You can mount it with FAT file system.
config SM_FTL
tristate "SmartMedia/xD new translation layer"
depends on BLOCK
select MTD_BLKDEVS
select MTD_NAND_ECC_SW_HAMMING
help
This enables EXPERIMENTAL R/W support for SmartMedia/xD
FTL (Flash translation layer).
Write support is only lightly tested, therefore this driver
isn't recommended to use with valuable data (anyway if you have
valuable data, do backups regardless of software/hardware you
use, because you never know what will eat your data...)
If you only need R/O access, you can use older R/O driver
(CONFIG_SSFDC)
config MTD_OOPS
tristate "Log panic/oops to an MTD buffer"
help
This enables panic and oops messages to be logged to a circular
buffer in a flash partition where it can be read back at some
later point.
config MTD_PSTORE
tristate "Log panic/oops to an MTD buffer based on pstore"
depends on PSTORE_BLK
help
This enables panic and oops messages to be logged to a circular
buffer in a flash partition where it can be read back as files after
mounting pstore filesystem.
If unsure, say N.
config MTD_SWAP
tristate "Swap on MTD device support"
depends on MTD && SWAP
select MTD_BLKDEVS
help
Provides volatile block device driver on top of mtd partition
suitable for swapping. The mapping of written blocks is not saved.
The driver provides wear leveling by storing erase counter into the
OOB.
config MTD_PARTITIONED_MASTER
bool "Retain master device when partitioned"
default n
depends on MTD
help
For historical reasons, by default, either a master is present or
several partitions are present, but not both. The concern was that
data listed in multiple partitions was dangerous; however, SCSI does
this and it is frequently useful for applications. This config option
leaves the master in even if the device is partitioned. It also makes
the parent of the partition device be the master device, rather than
what lies behind the master.
source "drivers/mtd/chips/Kconfig"
source "drivers/mtd/maps/Kconfig"
source "drivers/mtd/devices/Kconfig"
source "drivers/mtd/nand/Kconfig"
source "drivers/mtd/lpddr/Kconfig"
source "drivers/mtd/spi-nor/Kconfig"
source "drivers/mtd/ubi/Kconfig"
source "drivers/mtd/hyperbus/Kconfig"
endif # MTD