Re: NIU driver: Sun x8 Express Quad Gigabit Ethernet Adapter
From: Jesper Dangaard Brouer
Date: Wed Nov 12 2008 - 16:32:00 EST
Hi Google,
On Wed, 12 Nov 2008, David Miller wrote:
Guess what that does? The packet counters live in the upper
32-bits and the MARK bits live in the lower 32-bits of the
TX_CS register.
So it first reads the packet counters, and as a side effect that
clears the MARK bits in the TX_CS register. So when we read the lower
32-bits the MARK bits are always seen as zero.
For the thorough reader, the TX_CS Transmit Control and Status register is
described in table 26-15 page 761-762 in the PDF document titled:
"UltraSPARC T2 supplement to UltraSPARC architecture 2007", downloadable
from:
http://opensparc-t2.sunsource.net/specs/UST2-UASuppl-current-draft-HP-EXT.pdf
Cheers,
Jesper Brouer
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