MTD device structure
buffer given by fs driver
out of band selection structre
1 = place given buffer into the oob bytes
number of pages to prepare
1. Filesystem buffer available and autoplacement is off, return filesystem buffer 2. No filesystem buffer or autoplace is off, return internal buffer 3. Filesystem buffer is given and autoplace selected put data from fs buffer into internal buffer and retrun internal buffer
The internal buffer is filled with 0xff. This must be done only once, when no autoplacement happens Autoplacement sets the buffer dirty flag, which forces the 0xff fill before using the buffer again.