Re: [PATCH V1 net-next 0/3] net: stmmac: implement clocks

Hi Andrew,

Thanks for you explanation, I still don't quite understand what the use case it is, could you give me more details, thanks a lot!
AFAIK now, there are two connections methods, we can abstract the layer:
	MAC <-> MAC, there is no PHY attached. It seems to know as Fixed link, right?

Yes, this is the most common way of connecting a switch.

	MAC+PHY <-> PHY+MAC

Switches can be connected like this, but not often. Why pay for two
PHYs which you do not need?

From your expression, you should use an external Ethernet switch, if
yes, why Ethernet switch needs to use MDIO bus to access another
MAC's(STMMAC) PHY?

The switch is on the same board as the MAC. Take a look at:
https://netdevconf.info/2.1/papers/distributed-switch-architecture.pdf

It explains the DSA architecture.

   Andrew