nand oob layout assumptions

David Updegraff dave at cray.com
Thu Mar 25 13:44:50 EST 2004


Hi.

So I have a little ducttape-string-and-bailing wire driver here now that 
deals with these newer bigger Samsung K9xxx chips; am hitting snags 
around the declarations of oob areas.

The ecc calcluations within the driver are easy to deal with, straightup 
algorithm of ecc-space-needed = 3 * #-of-256byte chunks in the page.

But how to cope with that exposed oobinfo structure defn. in mtd.h that 
declares the all the universe uses 6 bytes for ecc in oob?

It seems we need the lo-level driver to declare (and allocate?) that 
oobinfo struct, and while we're at breaking everything by doing so, add 
a badblock_pos element to it, since these samsung chips mark badblocks 
not at offset:5 but offset:0 in oob.

I have no solution dreamed up yet on how to cope with the MEMSETOOBSEL
ioctl, though.  Do you?

-dbu.



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