[U-Boot] Ethernet PHY Power Down

[Fabio Estevam]

On Fri, Nov 6, 2015 at 6:22 PM, Michael Welling <mwelling at ieee.org> wrote:
> Lets try this again with list membership.
>
> I have run into an issue with a KSZ9031 Gigabit Ethernet PHY on an IMX6 module.
>
> After booting into Linux and rebooting the ethernet fails consistently.
>
> With a bit of investigation I found that the power-down bit in the PHY control
> register is being set on reboot.
>
> => dhcp
> BOOTP broadcast 1
> BOOTP broadcast 2
> BOOTP broadcast 3
> BOOTP broadcast 4
> BOOTP broadcast 5
> .
> .
> Abort
> => mii dump 1 0
> 0.     (1940)                 -- PHY control register --
>   (8000:0000) 0.15    =     0    reset
>   (4000:0000) 0.14    =     0    loopback
>   (2040:0040) 0. 6,13 =   b10    speed selection = 1000 Mbps
>   (1000:1000) 0.12    =     1    A/N enable
>   (0800:0800) 0.11    =     1    power-down
>   (0400:0000) 0.10    =     0    isolate
>   (0200:0000) 0. 9    =     0    restart A/N
>   (0100:0100) 0. 8    =     1    duplex = full
>   (0080:0000) 0. 7    =     0    collision test enable
>   (003f:0000) 0. 5- 0 =     0    (reserved)
>
> When I manually toggle the power down bit it starts to work again.
>
> => mii write 1 0 1140
> => dhcp
> FEC Waiting for PHY auto negotiation to complete........ done
> BOOTP broadcast 1
> DHCP client bound to address 192.168.0.12 (62 ms)
>
> I tried performing the above steps in the PHY driver code with little luck.
>
> When I toggle the bit in the code the first dhcp always fails but then it
> works on subsequent attempts.
>
> Any ideas?
> Has anyone else seen this issue with other PHYs?

Could you try to revert 59370f3fc as suggested here?
https://www.mail-archive.com/u-boot@lists.denx.de/msg191196.html