P1021MDS QE Ethernet Ports

Ioannis Kokkoris johnkokko at hotmail.com
Thu Sep 2 18:26:31 EST 2010

> From: johnkokko at hotmail.com
> To: linuxppc-dev at lists.ozlabs.org
> Subject: P1021MDS QE Ethernet Ports
> Date: Wed, 1 Sep 2010 15:11:56 +0300
> Hello,
> we are seeing a strange behavior when trying to use the QE Ethernet interfaces.
> ENET5 (UCC5 - RMII) interface on P1021MDS boards does not come up if there is no physical link on the ENET1 (UCC1 - MII) Port.
> It seems that interrupts from ENET5 are normally received but the link comes up and works properly only if we have physical connection on ENET1.
So far I found the following:

After adding traces, it seems that genphy_update_link() polls the correct device, with the correct address (0x03), but although a physical link is present in ENET5, the polling is not successful until there is a link in ENET1 (address 0x02)!

genphy_update_link: Dev: Micrel KS8041 ADD: 3 Status read 0x7849  (without ENET1 Link)
genphy_update_link: Dev: Micrel KS8041 ADD: 3 Status read 0x786D  (with    ENET1 Link)

How does the MDIO of ENET1 affect the management of the physical interface in a different HW address?

> Can anyone think of a possible reason for this behavior, is there a way to trace this problem?
> I can provide any further information needed.
> Any help would be appreciated,
> Regards,
> John
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