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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