From: Florian Fainelli <f.faine...@gmail.com>
Date: Sat, 24 Sep 2016 12:58:30 -0700
> This reverts commit 62469c76007e ("net: ethernet: bcmgenet: use phydev
> from struct net_device") because it causes GENETv1/2/3 adapters to
> expose the following behavior after an ifconfig down/up sequence:
>
> PING fainelli-linux (10.112.156.244): 56 data bytes
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.352 ms
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.472 ms (DUP!)
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.496 ms (DUP!)
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.517 ms (DUP!)
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.536 ms (DUP!)
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=1.557 ms (DUP!)
> 64 bytes from 10.112.156.244: seq=1 ttl=61 time=752.448 ms (DUP!)
>
> This was previously fixed by commit 5dbebbb44a6a ("net: bcmgenet:
> Software reset EPHY after power on") but the commit we are reverting was
> essentially making this previous commit void, here is why.
>
> Without commit 62469c76007e we would have the following scenario after
> an ifconfig down then up sequence:
>
> - bcmgenet_open() calls bcmgenet_power_up() to make sure the PHY is
> initialized *before* we get to initialize the UniMAC, this is
> critical to ensure the PHY is in a correct state, priv->phydev is
> valid, this code executes fine
>
> - second time from bcmgenet_mii_probe(), through the normal
> phy_init_hw() call (which arguably could be optimized out)
>
> Everything is fine in that case. With commit 62469c76007e, we would have
> the following scenario to happen after an ifconfig down then up
> sequence:
>
> - bcmgenet_close() calls phy_disonnect() which makes dev->phydev become
> NULL
>
> - when bcmgenet_open() executes again and calls bcmgenet_mii_reset() from
> bcmgenet_power_up() to initialize the internal PHY, the NULL check
> becomes true, so we do not reset the PHY, yet we keep going on and
> initialize the UniMAC, causing MAC activity to occur
>
> - we call bcmgenet_mii_reset() from bcmgenet_mii_probe(), but this is
> too late, the PHY is botched, and causes the above bogus pings/packets
> transmission/reception to occur
>
> Reported-by: Jaedon Shin <jaedon.s...@gmail.com>
> Signed-off-by: Florian Fainelli <f.faine...@gmail.com>
Applied and queued up for -stable.
