Re: gnumach2 & the serial port

[Roland McGrath]

You cited the code for oskit_bus_t devices, which has nothing to do with
the serial device in particular.

The code you cited is used if you do e.g.  "storecat -Tdevice @".  From
that you can see the bus structure and then use other names starting with @
for "bus-walk" syntax as described in the comment at the top of
oskit/unsupported/bus_walk_lookup.c.

You might have meant to cite the code that uses oskit_stream_t.
As the comment there says, that is a special case for the console.

In ds_routines.c, notice the #ifdef oskit_streamdev_open parts.  Perhaps
you meant to cite that.  It's in #ifdef because the oskit doesn't actually
have an oskit_streamdev_t interface.  I added that when I wrote the i8042
driver.  You'll need to build your own oskit with those changes (which I
must have posted here sometime in the past, or can again), and recompile
oskit-mach with the new oskit/dev/stream.h header installed.  That is the
baseline for stream-like devices, and sufficient for the i8042 where you
can get away without having any control operations.

You need a lot more glue work in oskit-mach to support a set of control
interfaces sufficient for serial devices.  Once that is done, it will take
some more hoops to use the freebsd sio driver that's in the oskit.  What
the oskit has is oskit_ttydev_t, which is a cop out using POSIX.1-style
interfaces rather than true driver-level interfaces exposing the hardware
models directly.