Triple Speed Ethernet (TSE) supports auto-negotiation only when used in 1000BASE-X/SGMII PCS mode.

This mode is available when implemented in FPGAs with embedded transceiver blocks used as the physical layer.
When using TSE as the MAC layer, auto-negotiation is done on the PHY side.

For details, please search for the keyword “AUTO NEGOTIATION” in the user guide at the URL link below and refer to it.
 https://www.altera.com/en_US/pdfs/literature/ug/ug_ethernet.pdf