On Friday 22 June 2007 05:18, Nobin Mathew wrote:
> Nay body has idea about OOB layout of YAFFS2?

This is a pretty terse question.  If you mean YAFFS2 on large
page NAND then...

The packed tags structure is defined in yaffs_packedtags2.h and
struct yaffs_ECCOther in yaffs_ecc.h. This is 28 bytes on most
systems with 32-bit unsigned ints.

The layout on NAND spare/oob (64 bytes) is determined by MTD,
see struct nand_oob_64 in nand_base.c. The version in 2.6.21 has
38 bytes of oob available starting at offset 2 within the
NAND chip's spare area.  So Yaffs tags start at offset 2.

If you want an answer for YAFFS2 code running on small-page NAND
the answer depends on a bunch of things determined by the version
and configuration of Yaffs and MTD, and possibly the platform's
NAND mapping driver which can configure MTD as it wishes.
You need to figure out what configuration/path is taken
in Yaffs yaffs_mtdif.c, what MTD api is being used; whether or
not MTD's AUTOPLACE is begin used, what the MTD layout policy is.

-imcd

BTW: I'm NOT cross-posting this reply to linux-kernel@vger.kernel.org