MTDs are well suited for logging critical data and the mtdoops driver
allows kernel panics/oops to be written to flash in a blackbox flight
recorder fashion allowing better debugging and analysis of crashes.

Any kernel oops in user context can be easily handled since the kernel
continues as normal and any queued mtd writes are scheduled. Any kernel
oops in interrupt context results in a panic and the delayed writes will
not be scheduled however. The existing mtd->write function cannot be
called in interrupt context so these messages can never be written to
flash.

This patch adds a panic_write function pointer that drivers can
optionally implement which can be called in interrupt context. It is
only intended to be called when its known the kernel is about to panic
and we need to write to succeed. Since the kernel is not going to be
running for much longer, this function can break locks and delay to
ensure the write succeeds (but not sleep).
Signed-off-by: NRichard Purdie <rpurdie@rpsys.net>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

We want drivers/mtd/{mtdcore, mtdsuper, mtdpart}.c to be built and linked
into the same mtd.ko module. Fix the Makefile to ensure this, and remove
duplicate MODULE_ declarations in mtdpart.c, as mtdcore.c already has them.
Signed-off-by: NSatyam Sharma <satyam@infradead.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Delete the allegedly obsolete "bank_size" member of struct mtd_info.
Signed-off-by: NRobert P. J. Day <rpjday@mindspring.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

If an erase operation fails, the address at which the
failure occurred is returned by the driver.  The MTD
partition must adjust this address (by subtracting the
partition offset) before returning to the caller.
This was not happening, which caused JFFS2 to mark
the wrong block bad!
Signed-off-by: NAdrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

During the MTD rework the oobavail parameter of mtd_info structure has become
private. This is not quite correct in terms of integrity and logic. If we have
means to write to OOB area, then we'd like to know upfront how many bytes out
of OOB are spare per page to be able to adapt to specific cases.
The patch inlined adds the public oobavail parameter.
Signed-off-by: NVitaly Wool <vwool@ru.mvista.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Remove unused and broken mtd->ecctype and mtd->eccsize fields
from struct mtd_info. Do not remove them from userspace API
data structures (don't want to breake userspace) but mark them
as obsolete by a comment. Any userspace program which uses them
should be half-broken anyway, so this is more about saving
data structure size.
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Many SLC NANDs support up to 4 writes at one NAND page. Add support
of this feature.
Signed-off-by: NArtem Bityutskiy <dedekind@infradead.org>

Signed-off-by: NYan Burman <yan_952@hotmail.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

As was discussed between Ricard Wanderlöf, David Woodhouse, Artem 
Bityutskiy and me, the current API for reading/writing OOB is confusing. 

The thing that introduces confusion is the need to specify ops.len 
together with ops.ooblen for reads/writes that concern only OOB not data 
area. So, ops.len is overloaded: when ops.datbuf != NULL it serves to 
specify the length of the data read, and when ops.datbuf == NULL, it 
serves to specify the full OOB read length.

The patch inlined below is the slightly updated version of the previous 
patch serving the same purpose, but with the new Artem's comments taken 
into account.

Artem, BTW, thanks a lot for your valuable input!
Signed-off-by: NVitaly Wool <vwool@ru.mvista.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

The raw read/write access to NAND (without ECC) has been changed in the
NAND rework. Expose the new way - setting the file mode via ioctl - to
userspace. Also allow to read out the ecc statistics information so userspace
tools can see that bitflips happened and whether errors where correctable
or not. Also expose the number of bad blocks for the partition, so nandwrite
can check if the data fits into the parition before writing to it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Hopefully the last iteration on this!

The handling of out of band data on NAND was accompanied by tons of fruitless
discussions and halfarsed patches to make it work for a particular
problem. Sufficiently annoyed by I all those "I know it better" mails and the
resonable amount of discarded "it solves my problem" patches, I finally decided
to go for the big rework. After removing the _ecc variants of mtd read/write
functions the solution to satisfy the various requirements was to refactor the
read/write _oob functions in mtd.

The major change is that read/write_oob now takes a pointer to an operation
descriptor structure "struct mtd_oob_ops".instead of having a function with at
least seven arguments.

read/write_oob which should probably renamed to a more descriptive name, can do
the following tasks:

- read/write out of band data
- read/write data content and out of band data
- read/write raw data content and out of band data (ecc disabled)

struct mtd_oob_ops has a mode field, which determines the oob handling mode.

Aside of the MTD_OOB_RAW mode, which is intended to be especially for
diagnostic purposes and some internal functions e.g. bad block table creation,
the other two modes are for mtd clients:

MTD_OOB_PLACE puts/gets the given oob data exactly to/from the place which is
described by the ooboffs and ooblen fields of the mtd_oob_ops strcuture. It's
up to the caller to make sure that the byte positions are not used by the ECC
placement algorithms.

MTD_OOB_AUTO puts/gets the given oob data automaticaly to/from the places in
the out of band area which are described by the oobfree tuples in the ecclayout
data structre which is associated to the devicee.

The decision whether data plus oob or oob only handling is done depends on the
setting of the datbuf member of the data structure. When datbuf == NULL then
the internal read/write_oob functions are selected, otherwise the read/write
data routines are invoked.

Tested on a few platforms with all variants. Please be aware of possible
regressions for your particular device / application scenario

Disclaimer: Any whining will be ignored from those who just contributed "hot
air blurb" and never sat down to tackle the underlying problem of the mess in
the NAND driver grown over time and the big chunk of work to fix up the
existing users. The problem was not the holiness of the existing MTD
interfaces. The problems was the lack of time to go for the big overhaul. It's
easy to add more mess to the existing one, but it takes alot of effort to go
for a real solution.

Improvements and bugfixes are welcome!
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The nand_oobinfo structure is not fitting the newer error correction
demands anymore. Replace it by struct nand_ecclayout and fixup the users
all over the place. Keep the nand_oobinfo based ioctl for user space
compability reasons.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The info structure for out of band data was copied into
the mtd structure. Make it a pointer and remove the ability
to set it from userspace. The position of ecc bytes is
defined by the hardware and should not be changed by software.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

MTD clients are agnostic of FLASH which needs ECC suppport.
Remove the functions and fixup the callers.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

These functions were never implemented and added only bloat to
partition and concat code.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

NAND writev(_ecc) support is not longer necessary. Remove it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

At least two flashes exists that have the concept of a minimum write unit,
similar to NAND pages, but no other NAND characteristics.  Therefore, rename
the minimum write unit to "writesize" for all flashes, including NAND.
Signed-off-by: NJoern Engel <joern@wh.fh-wedel.de>

'oobavail' parameter of mtd_info structure is now propagated to the MTD
partitions
Signed-off-by: NVitaly Wool <vwool@ru.mvista.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Don't assume eraseblock size is power of 2.
Dataflash can have aligned eraseblock size.

From: Peter Menzebach <pm-mtd@mw-itcon.de>
Acked-by: NArtem B. Bityutskiy <dedekind@infradead.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

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.
Signed-off-by: NNicolas Pitre <nico@cam.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!