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From: "Mark Chambers" <markc@mail.com>
To: <linuxppc-embedded@ozlabs.org>
Subject: MPC5200 PCI byte-swapping
Date: Thu, 30 Dec 2004 15:35:00 -0500	[thread overview]
Message-ID: <061001c4eeaf$0b5e1860$0301a8c0@chuck2> (raw)
In-Reply-To: C6D7331E-5A77-11D9-AECD-003065F9B7DC@embeddededge.com

I've just realized that the 5200 does byte-lane swapping
on all PCI accesses.  That is, if you write a 32 bit word
0x12345678, 0x12 will go out on byte 0, 0x34 on byte 1,
etc.  Unfortunately, my target, a T.I. DM642, does not
do this, so I've got a big/little endian mismatch.  A couple
of questions if anybody knows:

- Do all MPC8xxx processors do this - byte swap on
all PCI accesses, not just configuration space?

- Is there an elegant (simple) way to re-swap the bytes?
It's not a big problem really, but if there were a way to 
set LE mode on a particular page or something like that
it might be worth it.

Thanks,
Mark Chambers

  reply	other threads:[~2004-12-30 20:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-30 11:46 SMC/SCC uart problem with MPC852T David Jander
2004-12-30 15:30 ` Dan Malek
2004-12-30 20:35   ` Mark Chambers [this message]
2005-01-01 22:39     ` MPC5200 PCI byte-swapping Sylvain Munaut
2005-01-03 14:07       ` Mark Chambers
2005-01-03 16:47         ` Sylvain Munaut
2005-01-04  9:37           ` Stefan Nickl

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