Re-writing SMC91111 Ethernet driver

[Robert Catherall]

Hi,

The SMC91111 Ethernet driver was removed in commit

ecf1d2741d95f5f84e31dc1d0bef149d8ff1f0a3

because it had not been converted to DM_ETH.

I would be interested in doing the conversion and re-instating the 
driver to support Arm FastModel virtual prototypes (and Juno r0 hardware 
while I'm at it). I had a couple of questions

1. Is there any advantage or preference for starting with the previous 
code or am I free to start from another point?

My inclination was to copy'n'paste something like the SMC91x driver in 
order to get the outline, CONFIG_OF and DM_ETH framework correct and 
then fill out the actual moving parts with code from the previous 
implementation (or the Linux kernel if that has been updated more recently).

2. Can I ignore all the original CONFIG_ options and just write a driver 
that supports one fixed combination of those options and is only 
intended to work in the vexpress64 config?

Based on the commit above it was only still in use on two armltd 
platforms: integrator (splendidly obsolete) and vexpress64 (which covers 
my two cases).

I don't want to unnecessarily disadvantage another platform that could 
otherwise benefit from re-enabling the device again, but equally it 
would be nice to avoid the various macros for different types of access 
especially if I can't test them, and they are unlikely to ever be used.

Many thanks
Robert