superio and "shared" io port

[Andriy Gapon]

Here I am with Super I/O question again.
There is a certain Super I/O that is configured to use the same port for
entering/exiting configuration mode as the one that is used by fdc in
the same Super I/O. This is port 0x3f0.
I guess the hardware works by examining a value written to this port and
forwarding non-magic accesses to the fdc.

I wonder what is the best way to handle this double-use of an io port
with newbus isa code.

-- 
Andriy Gapon