Re: 2nd NIC on Rock64

[mlelstv%serpens.de@localhost (Michael van Elst)]

jmitchel%bigjar.com@localhost (Jason Mitchell) writes:

> Â Â Â  Pine64 sells a daughter board for the Rock64 that adds a second 
>ethernet port. However, I only see one interface, but it has two phys. 
>Am I correct in assuming that the two PHY's are for the two network 
>ports or am I mistaken.

If you have multiple ports you need multiple controllers.

The RK3328 only has a single controller (GMAC), but it does have two
interfaces for PHYs, one MII (10/100Mbps) where the PHY is internal,
and one RGMII (10/100/1000Mbps) for an external PHY. The main board
has such an external PHY that is used for Gigabit Ethernet.

The daughterboard connects the internal PHY to a second ethernet jack.

The driver can be configured to use either PHY, this is done in
the FDT, which currently selects the RGMII because that exists
on the main board.


Can you use both PHYs at the same time ? I doubt that, because there
is only a single GMAC. I can imagine that it could alternate between
both PHYs to make the appearance of two functional ports, sending
might even work, but receiving would have problems.

I have seen reports of people using the second Ethernet (with Linux)
though.



The two PHYs you see

>[Â Â Â Â  1.000006] rgephy0 at awge0 phy 0: RTL8211F 1000BASE-T media interface
>[Â Â Â Â  1.000006] rgephy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 
>1000baseT-FDX, auto
>[Â Â Â Â  1.000006] rgephy1 at awge0 phy 1: RTL8211F 1000BASE-T media interface
>[Â Â Â Â  1.000006] rgephy1: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 
>1000baseT-FDX, auto[Â Â Â Â  1.000006] awge0: interrupting on GIC irq 56

are the same external PHY on the RGMII interface. That device can be
configured to respond to phy 1-7 so that you could have multiple PHYs.
But phy 0 is a broadcast to control all PHYs in parallel (e.g. for a reset).

That behaviour isn't standard, so the driver probes all ids, including 0,
but as long there is only a single PHY the error is harmless.

-- 
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."