[U-Boot] Ethernet support broken for Wandboard Quad on master

[Charles Coldwell]

On Thu, Jul 18, 2013 at 5:07 AM, Sascha Silbe <t-uboot at infra-silbe.de> wrote:
>
>
> Charles, do you have any idea why your commit breaks ethernet support on
> Wandboard Quad?

I've never heard of the Wandboard Quad, so I suppose the short answer
is "no".  However, the philosophy of the patch I submitted was:

1. Check the ESTATEN (Extended Status Enabled) bit in the BMSR (Basic
Mode Status Register at address 0x01) MII register.

2. If it is set, read the ESTATUS (Extended Status) register

3. If the ESTATUS register indicates that it supports 1000BASE-X or
1000BASE-T, set the corresponding speed and duplex fields of the
phy_device structure.

The MDIO registers in the Xilinx 1000BASE-X phy are documented here

http://www.xilinx.com/support/documentation/user_guides/ug194.pdf

starting on page 122.

ESTATEN is bit 8 of the BMSR at address 0x01; ESTATUS is at register
address 15 and should always hold the value 0x8000 on the Xilinx
1000BASE-X phy since the only mode it supports is 1000BASE-X full
duplex.

So, AFAICS, the patch should function correctly if both phys are using
the same register maps.  However, I don't think the Xilinx register
map is blessed by the MDIO standards bodies, and therein might lie the
trouble.

Can somebody look up the phy register maps for the i.MX6 phy (if it's
built in) or whatever the Wandboard is using?

--
Charles M. Coldwell, W1CMC
Belmont, Massachusetts, New England
"Turn on, log in, tune out"