Re: [PATCH devicetree 3/4] arm64: dts: fsl: ls1028a: add node for Felix switch

Hi Andrew,

On Mon, 17 Feb 2020 at 17:29, Andrew Lunn [off-list ref] wrote:

Hi Vladimir

quoted

+                                     /* Internal port with DSA tagging */
+                                     mscc_felix_port4: port@4 {
+                                             reg = <4>;
+                                             phy-mode = "gmii";

Is it really using gmii? Often in SoC connections use something else,
and phy-mode = "internal" is more appropriate.

What would be that "something else"? Given that the host port and the
switch are completely different hardware IP blocks, I would assume
that a parallel GMII is what's connecting them, no optimizations done.
Certainly no serializer. But I don't know for sure.
Does it matter, in the end?

quoted

+                                             ethernet = <&enetc_port2>;
+
+                                             fixed-link {
+                                                     speed = <2500>;
+                                                     full-duplex;
+                                             };

gmii and 2500 also don't really go together.

Not even if you raise the clock frequency?

     Andrew

Thanks,
-Vladimir