I have a very novice question.
Currently, I'm looking at something about Raspberry Pi network interface cards.

I found that GPIO provide a kind of alternative function name RGMII_MDIO, but seems it's implement haven't use this kind of method, but Instead, it uses a direct address manipulation via MMIO to use MDIO (At least from my perspective it directly write int into MMIO mem.）
Are there any special considerations in the implementation of this section?