https://docs.amd.com/r/2.6-English/pg292-ethernet-1-10-25g/Register-Space?contentId=XY2rg6U6BIWWjvt~D7gaaQ
Register Space - Register Space - 2.6 English - PG292
All the control and status registers are memory mapped. After power-up or reset, you can reconfigure the core parameters from their defaults at any time.
registerspaceenglish