Re: [net-next: PATCH v3 5/6] net: mvpp2: enable using phylink with ACPI

[Marcin Wojtas]

Hi,

śr., 23 cze 2021 o 22:37 Andrew Lunn <andrew@xxxxxxx> napisał(a):
>
> > +static bool mvpp2_use_acpi_compat_mode(struct fwnode_handle *port_fwnode)
> > +{
> > +     if (!is_acpi_node(port_fwnode))
> > +             return false;
> > +
> > +     return (!fwnode_property_present(port_fwnode, "phy-handle") &&
> > +             !fwnode_property_present(port_fwnode, "managed") &&
> > +             !fwnode_get_named_child_node(port_fwnode, "fixed-link"));
>
> I'm not too sure about this last one. You only use fixed-link when
> connecting to an Ethernet switch. I doubt anybody will try ACPI and a
> switch. It has been agreed, ACPI is for simple hardware, and you need
> to use DT for advanced hardware configurations.
>
> What is your use case for fixed-link?
>

Regardless of the "simple hardware" definition or whether DSA + ACPI
feasibility, you can still have e.g. the switch left in "unmanaged"
mode (or whatever the firmware configures), connected via fixed-link
to the MAC. The same effect as booting with DT, but not loading the
DSA/switch driver - the "CPU port" can be used as a normal netdev
interface.

I'd also prefer to have all 3 major interface types supported in
phylink, explicitly checked in the driver - it has not been supported
yet, but can be in the future, so let's have them covered in the
backward compatibility check.

Best regards,
Marcin