references:
http://www.beyondlogic.org/serial/serial.htm
http://jamesthornton.com/freebsd/articles/serial-uart/
http://dugeem.net/david/work/freebsd-serial.html
http://dugeem.net/david/work/etc/sio.c

Moschip:
http://lxr.linux.no/linux+v2.6.28.7/drivers/parport/parport_serial.c#L108
http://lxr.linux.no/linux+v2.6.28.7/drivers/pci/quirks.c#L1462

if you can understand it:
http://lxr.linux.no/linux+v2.6.28.7/drivers/serial/