I am listing down certain threads which might be useful
- PSoC 5LP Freesoc 2, and ethernet
- How to use Ethernet module
They mention the type of ethernet controller used and also how they interfaced with PSoC. Just make sure to port/modify it according to your target device.
Just ensure the ethernet controller is compatible with 1000 Base-T networks. The PSoC 5 has clocks ranging from 24Mhz upto 74 Mhz based on what device you are using, which should be able to provide necessary clocking for the SPI communication.