The RK3568 GMAC is a DesignWare Ethernet QoS core (version 5.x), which dwc
supports since 9006a6ad1b30. Add the SoC specific code:
- Select the GMAC0 or GMAC1 GRF registers from the device address, set the PHY interface and the RX/TX clock delays.
- Switch the RGMII speed clock according to the media (the device tree only selects the gigabit one).
- Compute the MDIO clock range from the main clock, the CSR clock of this core.
- Set DWC_HAS_GMAC5 so that the QoS backend is used.
eqos also matches this device, probe with a higher priority until it is
removed.