> how I can access PHY device registers via MDIO/MII?

The network driver does this all the time, for link
management - see the mii.c source.

> have found "DCMD_IO_NET_MIIPHY"

I just grepped the io-net driver source - I really,
really wish it was publicly available, but I understand
if we do, our lawyers will tar and feather us - and 
it appears that this extension was added for the
"tulip" driver.

> Can I just add DCMD_IO_NET_MIIPHY to the devctl
> switch statement?

That's what the tulip driver did - it just calls
a function, with pointers to the driver structure,
and the devctl data.

> Do I need some locking against other threads here? 

You sure do!  You must ensure that you acquire the
same mutex as the driver does, before it accesses
the mii registers.

> Can I "invent" my own parameter formats for 
> DCMD_IO_NET_MIIPHY or is there any standard?

I would just copy what the tulip driver does.
I can probably give you some source, as long
as our lawyers don't find out about it.

> how is this all solved with io-pkt? 

I don't think io-pkt has an API for reading
and writing network driver MII registers, but
I may be mistaken.  Rob?  Sean?

--
aboyd

> parameter formats for DCMD_IO_NET_MIIPHY or is there any standard?

At the end of usr/include/hw/nicinfo.h I see a typedef
of nic_miiphy_dcmd_t ... that struct is passed in as
the "data" for the devctl, to the tulip driver.  I
would probably just copy that.  There are a bunch of
NIC_MIIPHY defines there, that you will probably find
handy.

--
aboyd