[Yaffs] Verify problem with ECC

[Charles Manning]

On Friday 12 August 2005 20:34, Pihet Jean-jpih01 wrote:

> >
> >The trick is to do this in excatly one place only (ie YAFFS or mtd).
>
> So for the moment we have to hack things to make it work.

From YAFFS' perspective this is the same as the mtd doing it. (ie YAFS says 
"not my problem")
>
> >You also need to make sure that yaffs is using the same OOB layout at mtd.
> > The standard YAFFS layout is as used by SmartMedia. If you are using some
> > other OOB layout (quyite likely the case with some hardware ECC), then
> > you need to ensure that: 1) YAFFS is not doing ECC
>
> OK the HW is doing it
>
> >2) The spare bytes are being placed in the correct area. You might need to
> > write some byte shuffling code.
>
> I changed the yaffs_Spare struct for now, but I am sure there is a better
> solution as you indicated.
>
>
> It would be nice to converge to the right solution to have YAFFS working on
> top on MTD for all boards. What is the best solution to this ? Will the
> byte shuffling code be efficient ?

Right now there is a major code clean up etc underway. This should be 
completed in the next few days.

At present there is a small issue with the mtd interface and the way it 
handles read_oob (it does this raw instead of doing AUTOPLACE). When the new 
AUTOPLACE mechanism is in place, then YAFFS will use that mechanism in 
preference to yaffs_Spare. This should make things a lot cleaner.

This is high priority on the YAFFS side and (hopefully) on the mtd side.  I 
expect this issue to be resolved before the end of this month. In the mean 
time, you'll just need to hack either YAFFS or the mtd to get what you need.

-- CHarles