Add support for on-flash bad block table. This makes U-Boot handle an existing
BBT correctly.

Signed-off-by: David Dueck <davidcdueck@googlemail.com>
Reviewed-by: Boris BREZILLON <boris.brezillon@free-electrons.com>
CC: Boris BREZILLON <boris.brezillon@free-electrons.com>
CC: Josh Wu <josh.wu@atmel.com>
CC: Andreas Bießmann <andreas.devel@googlemail.com>
CC: Scott Wood <scottwood@freescale.com>
Acked-by: Josh Wu <josh.wu@atmel.com>

Testing showed, that commands like STATUS made the buffer dirty
when executed with NFC_SECSZ set to the page size. It looks
like the controller transfers bogus data when this register
is configured. When setting it to 0, the buffer does not get
altered while the status command still seems to work flawless.

Signed-off-by: Stefan Agner <stefan@agner.ch>

The driver tries to re-use the page buffer by storing the page
number of the current page in the buffer. The page is only read
if the requested page number is not currently in the buffer. When
a block is erased, the page number is marked as invalid if the
erased page equals the one currently in the cache. However, since
a erase block consists of multiple pages, also other page numbers
could be affected.

The commands to reproduce this issue (on a written page):
> nand dump 0x800
> nand erase 0x0 0x20000
> nand dump 0x800

The second nand dump command returns the data from the buffer,
while in fact the page is erased (0xff).

Avoid the hassle to calculate whether the page is affected or not,
but set the page buffer unconditionally to invalid instead.

Signed-off-by: Stefan Agner <stefan@agner.ch>

This command is only enabled by one board, complicates the NAND code,
and doesn't appear to have been functioning properly for several
years.  If there are no bad blocks in the NAND region being written
nand_write_skip_bad() will take the shortcut of calling nand_write()
which bypasses the special yaffs handling.  This causes invalid YAFFS
data to be written. See
http://lists.denx.de/pipermail/u-boot/2011-September/102830.html for
an example and a potential workaround.

U-Boot still retains the ability to mount and access YAFFS partitions
via CONFIG_YAFFS2.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

The CONFIG_MTD_NAND_VERIFY_WRITE has been removed from Linux for some
time and a more generic method of NAND verification now exists in U-Boot.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>

Previously NAND writes were not verified and could fail silently.  Add
a verification step after all writes to NAND.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>

Add nand_verify() and nand_verify_page_oob().  nand_verify() verifies
NAND contents against an arbitrarily sized buffer using ECC while
nand_verify_page_oob() verifies a NAND page's contents and OOB.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Tested-by: Heiko Schocher <hs@denx.de>
Acked-by: Heiko Schocher <hs@denx.de>