Re: Q: fixed link

[Ranran <ranshalit@gmail.com>]

On Sun, Sep 8, 2019 at 12:05 PM Andrew Lunn <andrew@lunn.ch> wrote:
>
> On Sun, Sep 08, 2019 at 10:30:51AM +0300, Ranran wrote:
> > Hello,
> >
> > In documentation of fixed-link it is said:"
> > Some Ethernet MACs have a "fixed link", and are not connected to a
> > normal MDIO-managed PHY device. For those situations, a Device Tree
> > binding allows to describe a "fixed link".
> > "
> > Does it mean, that on using unmanaged switch ("no cpu" mode), it is
> > better be used with fixed-link ?
>
> Hi Ranran
>
> Is there a MAC to MAC connection, or PHY to PHY connection?
>
> If the interface MAC is directly connected to the switch MAC, fixed
> link is what you should use. The fixed link will then tell the
> interface MAC what speed it should use.
>
> If you have back to back PHYs, you need a PHY driver for the PHY
> connected to the interface MAC, to configure its speed, duplex
> etc. The dumb switch should be controlling its PHY, and auto-neg will
> probably work.
>
>          Andrew


Hi,

We are using RGMII mode with the switch, which probably means
mac-to-mac (as far as I understand).

Does it mean we can choose between these 2 options:
1. configure dsa switch in device tree
2. configure fixed link in device tree


Thanks,
ranran