Weird 5200/mtd-ram problem
albrecht.dress at arcor.de
Thu May 21 05:36:45 EST 2009
Am 20.05.09 16:23 schrieb(en) Gary Thomas:
> > In Linux, when I write the file to /dev/mtdx, the last dword of
> each block is broken, e.g. when running "dd if=pattern of=/dev/mtd5
> bs=512" the dword's at offset 0x1fc, 0x3fc, ... are 0x0000aaaa
> (instead of 0x0055aaff), if I use bs=1024 the dwords at 0x3fc, 0x7fc,
> ... show this value, if I use bs=4096 the dword at 0xffc shows this
> value, etc. I looked at the CS/WR lines with a scope, and I couldn't
> see anything special. The timing should be fine, as u-boot uses the
> same as Linux.
> > Any idea what goes wrong here? I guessed I missed something in the
> LPB setup...
> Check your cache setup - the BDI is most certainly not accessing this
> via the Data cache whereas Linux probably will be.
Hmm, yes - I didn't touch the vanilla Lite5200B Linux setup there,
which has a flash chip at cs1...
If it is really a cache problem (I'm away now from my test board) -
isn't a sync sufficient after doing the copy to the external ram
(lpb/cs1)? What is the proper approach for devices attached to the
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