linux-toradex.git/include/linux/mtd/mtd.h, branch v3.0-rc3

mtd: kill CONFIG_MTD_PARTITIONS

2011-05-25T01:25:35+00:00

Now that none of the drivers use CONFIG_MTD_PARTITIONS we can remove
it from Kconfig and the last remaining uses.

Signed-off-by: Jamie Iles 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: remove add_mtd_partitions, add_mtd_device and friends

2011-05-25T01:25:16+00:00

These symbols are replaced with mtd_device_register() (and removal with
mtd_device_unregister()) for public registration.

Signed-off-by: Jamie Iles 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: introduce mtd_device_(un)register()

2011-05-25T01:12:36+00:00

To prepare for the removal of add_mtd_device and add_mtd_partitions(),
introduce mtd_device_register().  This will create partitions if they
are supplied or register the whole device if there are no partitions.

Once all drivers are converted to use mtd_device_register(),
add_mtd_device() and add_mtd_partitions() will be made internal only.

v2: move kerneldoc to implementation file and fixup some kerneldoc
warnings.

Artem: tweak comments: remove junk tabs, use dots consistently.

Signed-off-by: Jamie Iles 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: create function to perform large allocations

2011-05-25T00:59:43+00:00

Introduce a common function to handle large, contiguous kmalloc buffer
allocations by exponentially backing off on the size of the requested
kernel transfer buffer until it succeeds or until the requested
transfer buffer size falls below the page size.

This helps ensure the operation can succeed under low-memory, highly-
fragmented situations albeit somewhat more slowly.

Artem: so this patch solves the problem that the kernel tries to kmalloc too
large buffers, which (a) may fail and does fail - people complain about this,
and (b) slows down the system in case of high memory fragmentation, because
the kernel starts dropping caches, writing back, swapping, etc. But we do not
really have to allocate a lot of memory to do the I/O, we may do this even with
as little as one min. I/O unit (NAND page) of RAM. So the idea of this patch is
that if the user asks to read or write a lot, we try to kmalloc a lot, with GFP
flags which make the kernel _not_ drop caches, etc. If we can allocate it - good,
if not - we try to allocate twice as less, and so on, until we reach the min.
I/O unit size, which is our last resort allocation and use the normal
GFP_KERNEL flag.

Artem: re-write the allocation function so that it makes sure the allocated
buffer is aligned to the min. I/O size of the flash.

Signed-off-by: Grant Erickson 
Tested-by: Ben Gardiner 
Tested-by: Stefano Babic 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: add writebufsize field to mtd_info struct

2011-01-06T15:35:50+00:00

This field will be used to indicate the write buffer size
of the MTD device. UBI will set it's minimal I/O unit size
(min_io_size) to the indicated write buffer size. By this
change we intend to fix failed recovery of UBIFS partitions
we currently observe on NOR flash when mounting the partition
after unclean unmount.

Currently the min_io_size is set to mtd->writesize (which is 1
byte for NOR flash). But flash programming is often done from
prepared write buffer containing multiple bytes and is performed
in one programming operation which could be interrupted by a power
cut or a system reset causing corrupted (partially written) areas
in a flash sector. Knowing the size of potentially corrupted areas
UBIFS scanning and recovery algorithms are able to perform
successful recovery.

In case of NOR flash minimal I/O size must be equal to the
maximal size of the write buffer used by embedded flash
programming algorithm. In case of NAND flash mtd->writebufsize
should be equivalent to mtd->writesize.

The subsequent patches will add mtd->writebufsize initialization
where needed.

Signed-off-by: Anatolij Gustschin 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: edit comments on deprecation of ioctl ECCGETLAYOUT

2010-10-24T22:37:27+00:00

There were some improvements and additions necessary in the
comments explaining of the expansion of nand_ecclayout, the
introduction of nand_ecclayout_user, and the deprecation of the
ioctl ECCGETLAYOUT.

Also, I found a better placement for the macro MTD_MAX_ECCPOS_ENTRIES;
next to the definition of MTD_MAX_OOBFREE_ENTRIES in mtd-abi.h. The macro
is really only important for the ioctl code (found in drivers/mtd/mtdchar.c)
but since there are small edits being made to the user-space header, I
figured this is a better location.

Signed-off-by: Brian Norris 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: nand: expand nand_ecc_layout, deprecate ioctl ECCGETLAYOUT

2010-10-24T22:37:24+00:00

struct nand_ecclayout is too small for many new chips; OOB regions can be as
large as 448 bytes and may increase more in the future. Thus, copying that
struct to user-space with the ECCGETLAYOUT ioctl is not a good idea; the ioctl
would have to be updated every time there's a change to the current largest
size.

Instead, the old nand_ecclayout is renamed to nand_ecclayout_user and a
new struct nand_ecclayout is created that can accomodate larger sizes and
expand without affecting the user-space. struct nand_ecclayout can still
be used in board drivers without modification -- at least for now.

A new function is provided to convert from the new to the old in order to
allow the deprecated ioctl to continue to work with truncated data. Perhaps
the ioctl, the conversion process, and the struct nand_ecclayout_user can be
removed altogether in the future.

Note: There are comments in nand/davinci_nand.c::nand_davinci_probe()
regarding this issue; this driver (and maybe others) can be updated to
account for extra space. All kernel drivers can use the expanded
nand_ecclayout as a drop-in replacement and ignore its benefits.

Signed-off-by: Brian Norris 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: Remove obsolete include

2010-08-08T20:19:42+00:00

Signed-off-by: David Woodhouse

mtd: Update copyright notices

2010-08-08T19:58:20+00:00

Signed-off-by: David Woodhouse

mtd: add an ioctl to query the lock status of a flash sector

2010-08-02T08:03:41+00:00

This patchs adds a way for user space programs to find out whether a
flash sector is locked. An optional driver method in the mtd_info struct
provides the information.

Signed-off-by: Richard Cochran 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse