On Saturday 24 October 2009 05:05:35 Babrian Viktor wrote:
> e a uC with a nand flash controller that computes ECC on the
> whole page at once. It has no separate bytes for spare area ECC. Which
> means that oob data cannot be written separately. Yaffs is going to be
> used on this chip and the question is that does yaffs write oob data
> separately? I looked into the sources and I see write_oob() function calls

yaffs1 writes tags seperately when it writes deletion markers.
yaffs2 only ever writes tags together with data.

The write_oob() call does not only write the oob area, it also writes the 
data. From yaffs_mtdif2.c:
	ops.mode = MTD_OOB_AUTO;
	ops.ooblen = (dev->inbandTags) ? 0 : packed_tags_size;
	ops.len = dev->totalBytesPerChunk;
	ops.ooboffs = 0;
	ops.datbuf = (__u8 *)data;
	ops.oobbuf = (dev->inbandTags) ? NULL : packed_tags_ptr;
	retval = mtd->write_oob(mtd, addr, &ops);

-- CHarles