Newbie asking directions...

[Patrick Roberts]

I am new to hardware and Linux programming and have a user-space programming
question that probably isn't appropriate for this list, but I'm not sure where
else to go.  I've tried a bunch of searches and haven't found anything useful,
so if one of the gurus here could point me to a resource or give me a direction
to go in I would be eternally greatful.  (Help me Kernel-wan Kanobi...)

Q:
  I have an AGP video card (with a closed source X driver).  I would like to
access the address-mapped hardware registers to control some special features. 
I can get the base address through /proc, and I have docs on the card, but
what's the most 'friendly' way to read and write to these registers in Linux
with C? (not std. PCI registers).

Thanks for any help or information :)