Re: [PATCH] 2.5.17 /dev/port

[Alan Cox]

> On non-Intel platforms, with no dedicated IOIO opcodes, IOIO is
> usually implemented as a specific memory range.  In that case, the
> only way to allow user-space access to it would be to mmap() that
> range... which means iopl() inb() and outb() on those platforms might
> be implemented either as open, readp and writep, respectively, or by
> iopl() being open() followed by mmap().

mmap and some other logic in certain cases. An outb stalls until the I/O
hits the device even on PCI.  Either way thats really about what you
put into /dev/port (either the i/o logic or a map of /dev/mem with slightly
tweaked args)