Extending sys/dev/mii

[Juli Mallett]

On Sat, Feb 11, 2012 at 20:59, Warner Losh <imp at bsdimp.com> wrote:
>> The trouble in this whole mess (where FDT may help) is that phy's for
>> arge0 may actually sit on arge1. So you can't probe/attach the miibus
>> on arge0 until you've probe/attached arge1, so the arge1 MII registers
>> can be tickled.
>
> The PHYs don't sit on arge1.  They sit on another device that the driver bogusly assumes is tightly coupled to arge1, when in fact it isn't.

YES!  Thank you!  And even if it were tightly coupled in hardware,
there's no reason our device tree needs to mirror that, FDT or not.
Just break out an "arge controller" device, attach arge0 and arge1 to
it, and let it manage the MDIO bus.  No shortcomings, as far as I can
tell.  You can even be extra clever and say that the switch is
attached to that device, not either of the arge devices, and that one
of the arge devices happens to be connected to the switch's CPU/host
port.  But that's probably a bit much to ask for.