Re: registers access in user space deive driver

[Henrik Nordstrom <hno@marasystems.com>]

On Fri, 12 Nov 2004, Yueting Shen wrote:

> > For IOIO see iopl
> >
> >         iopl - change I/O privilege level
> how? should I invoke it before inb&outb?

yes,

> and the privilege level should be set
> less than or equal to 3?

Not entirely sure what the different levels < 3 are. At level 3 you have 
access to all ports.

> > Not sure about MMIO, but I suppose it is possible to mmap the
> > appropriate regions of /dev/mem?
>
> Where can I find an example for this function since its arguments have special
> requirement(as to offset and fd)

For documentation on /dev/mem:

   man mem

For documenation on mmap:

   man mmap

or your favorite UNIX programming book.


Regards
Henrik
-
: send the line "unsubscribe linux-net" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html