On Fri, 2 Jul 2021 02:55:54 +0200 Andrew Lunn <andrew@xxxxxxx> wrote: > On Thu, Jul 01, 2021 at 02:53:47AM +0200, Marek Behún wrote: > > There are devices where the MAC signals from the ethernet controller are > > not directly connected to an ethernet PHY or a SFP cage, but to a > > multiplexer, so that the device can switch between the endpoints. > > > > For example on Turris Omnia the WAN controller is connected to a SerDes > > switch, which multiplexes the SerDes lanes between SFP cage and ethernet > > PHY, depending on whether a SFP module is present (MOD_DEF0 GPIO from > > the SFP cage). > > At the moment, i don't think phylink supports this. It does not have a > way to dynamically switch PHY. If the SFP disappears, you probably > want to configure the PHY, so that it is up, autoneg started, > etc. When the SFP reappears, the PHY needs to be configured down, the > SFP probably needs its TX GPIO line set active, etc. None of this > currently exists. Of course this is not supported by phylink: it can't be, since we don't even have a binding description :) I am figuring out how to do correct binding while working on implementing this into phylink. > The Marvell switches have something similar but different. Which ever > gets link first, SFP or PHY gets the data path. In this case, you > probably want phylink to configure both the SFP and the PHY, and then > wait and see what happens. The hardware will then set the mux when one > of them gets link. phylink should then configure the other > down. Again, non of this exists at the moment. > > I would imaging a similar binding could be used for these two > conditions. But until we get the needed code, it is hard for me to > say. So i think i would prefer to wait until we do have code. > I now have an idea that might be sane for bindings, so next time I will send the code as well. > I also wonder how wise it is to put this into the generic ethernet > controller binding. Muxing based on MOD_DEF0 i expect to be very > rare. Muxing based on first port having link seems more likely. But > both i expect are pretty unusual. So i would be tempted to make it a > standalone binding, which can be imported into an MAC binding which > actually needs it. Or it actually becomes part of the phylink > binding, since this all appears to be PHY related, not MAC. > > Andrew We'll see. Stay tuned for my patch series. :) Marek
