> I have a small question.  I am trying to port an old usermode hw io
> testing program that I wrote a long time ago from linux to netbsd.
> My question is, how does one do user mode hw io using bus_space_...

One doesn't.  The bus-space functions - and perhaps more importantly,
the support behind them - are kernel-only.  Indeed, one of the kernel's
jobs is to keep userland away from direct access to the hardware.

> So, am I trying to do something impossible, or not ?  i.e. can I
> compile a user mode program, to be run as root, which uses
> bus_space_peek and _poke, or do I have to write a proper driver ?

You'll need to write a driver (though for memory-mapped stuff, you can
in principle use /dev/mem - depending on your device's interface, this
may be good enough).

Unless your device has requirements such as DMA or tight timing, you
may well be able to get away with a very basic driver that just gives
userland a more or less direct interface to the appropriate bus-space
calls.  (It would be an immense security hole for normal use, or
distribution, but it may nevertheless be suitable on an
experimental-hackery system.)

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