Accessing my NIC's hardware Help!!

Hello,

I've been working on making my own OS and I have a Broadcom 570x NIC.
The Tigon3 driver does the trick for interfacing with my controller
under linux so I've been looking at the code trying to figure out how
to talk to the hardware, but I can't seem to see where or how to access
the NIC's hardware.

The best would be to find the specs for my hardware, but I can't seem
to get my hands on anything pertinent.

Could somebody point me in the right direction? It would save me an
awful lot of time.

Is it possible to access the device through ports directly, or do I
have to use the PCI bus?

I am not trying to make anything generic. Something very crude and very
specific will do just fine.

Regards
Jean-Francois Michaud