Confusion about memory mapped I/O

[Amit Uttamchandani]

Hi,

I am trying to understand the magic behind memory mapped I/O in linux
device drivers. I understand the concepts behind setting up memory
mapped I/O but I am confused about how the data (once written into
memory) gets transferred onto the bus and onto the peripheral.

E.g. many network drivers use memory mapped I/O and this makes it quite
generic but how do you specify the bus in all this?

Thanks for any help,
Amit