Cadence Ethernet MAC has a feature named user_io, which provides
some input and some output signals for arbitrary purpose in the SoC.
From the driver code, I understand that, on Atmel SoC, it is used to
drive the PHY mode.
At least on Cadence IP7014 r1p12, this feature is optional, and I am
working on a SoC that does not instantiate it. The presence of this
feature is advertised in DCFG1, this patch merely disables the access
to the user_io register based on this information.
I did not apply this change to the non-gigabit capable versions of
the IP, as I do not have documentation for them, and a new non-gigabit
instance is unlikely to appear. I prefer avoiding regressions on old
systems.
Signed-off-by: Christian DREHER <christian.dreher@nanoxplore.com>
d7fe1f4333