Re: [PATCH v4 06/12] ARM: dove: add gigabit ethernet and mvmdio devicetree nodes

From: Sebastian Hesselbarth
Date: Wed May 22 2013 - 14:44:30 EST

On 05/22/2013 07:48 PM, Jason Cooper wrote:
On Wed, May 22, 2013 at 07:42:36PM +0200, Sebastian Hesselbarth wrote:
Hmm, maybe a little bit too early. While restoring the MAC address now
works, another bug arises which I guess is related with phy setup
and aneg.

Will investigate and update patch set accordingly.

Cool, chances are, we should be able to take that patch in by itself for
this merge window...

Which patch do you mean? The local-mac-address workaround will only be
available for DT mv643xx_eth because it uses the DT node to store the

Anyway, I found the bit that caused the other issue. It is the
Clk125_Bypass_En bit in PORT_SERIAL_CONTROL1 register. What bothers me
about it is:
- Only Dove and Kirkwood have the bit, MV78x00 doesn't have it, Orion5x
doesn't have the register at all. With ppc mv64x60 I can only guess,
but think it is like in Orion5x.
- Reset value of that bit should be 0, but after gating clock on
Kirkwood it is set to 1 causing wrong port clock to be selected.
Also Thomas Petazzoni confirmed that it is set after reset so
either FS is wrong about it or BootROM messes with it.
- Kirkwood and Dove FS tell me that port link must be down when you
change the bit.

As I can't be sure about how mv643xx_eth will behave on other platforms
except Kirkwood and Dove when writing that register, I tend to force
that bit to zero in the driver but only for those two by #ifdefs.

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