Opencores Ethernet with Phy

I wish to assemble an Ethernet driver based on the opencores module for 
low level functionality with phy support and the standalone layer for 
io. Looking at the ecos database (ecos-3.0) it appears only the Arm, 
Rattler/fcc and Moab/ppc405 PowerPC have used phy support. At the same 
time no other hardware family use unmodified opencores drivers (granted 
interfaces are similar for stop, start, can_send, send). Why have 
opencores drivers been so  unpopular among other processor families in 
that regard?  Why is the phy module used so seldom?   Are there further 
issues with the choice of io layer I should know about?  I chose 
standalone for the complement with Redboot rather than for an ECOS 
application.

Thanks for any guidance. -Les

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