[RFC v8 net-next 15/16] net: dsa: felix: add phylink_get_caps capability

[Russell King (Oracle)]

On Fri, Sep 09, 2022 at 11:33:59AM -0700, Colin Foster wrote:
> Seemingly because net/dsa/port.c checks for phylink_validate before it
> checks for mac_capabilties, it won't make a difference there, but this
> seems ... wrong? Or maybe it isn't wrong until I implement the QSGMII
> port that supports 2500FD (as in drivers/net/ethernet/mscc/ocelot_net.c
> ocelot_port_phylink_create())

No, the code in dsa_port_phylink_validate() is exactly what I intend.

If there's a phylink_validate() function, then that gets used to cater
for Ocelot's rate adaption in the PCS (where the link modes are not
limited by the interface mode.)

If there isn't a phylink_validate() function, then we require that
mac_capabilities() is filled in, and if it is, we use the generic
validator - essentially I want to see everyone filling in both the
supported interface masks and the MAC capabilities no matter what.

The Ocelot rate adaption is something that needs to be tidied up, but
until that has been done, Ocelot needs to have the phylink_validate()
hook. Ocelot is currently the sole user of this hook.

I have some experimental patches to address this, but nothing that I
felt happy to send out yet.

-- 
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