Honestly I would postpone untile we have a clear idea of what is
actually part of the PHY and what can be handled externally... Example
setting the clock in gcc, writing a specific driver...
That is really core of the problem here. We have no reliable
description of the hardware. The datasheet often starts with a block
diagram of the PHY package. Sometimes there is a product brief with
the same diagram. We need that published. I'm not asking for the full
data sheet, just the introductory text which gives a high level
overview of what the hardware actually is. Then we can sketch out a
high level Linux architecture for the PHY package.