On Tue, Jun 23, 2020 at 11:49:28AM +0000, Ioana Ciornei wrote:
> > This should be added to phylink_mii_c45_pcs_get_state(). There is nothing
> > that
> > is Lynx PCS specific here.
>
> The USXGMII standard only describes the auto-negotiation word, not the MMD
> where this can be found (MMD_VEND2 in this case).
> I would not add a generic phylink herper that reads the MMD and also
> decodes it.
> Maybe a helper that just decodes the USXGMII word read from the
> Lynx module - phylink_decode_usxgmii_word(state, lpa) ?
Yes, you're right - as they come from the vendor 2 MMD, there's no
standard. So yes, just a helper to decode the USXGMII word please.
> > > +static void lynx_pcs_get_state_2500basex(struct mdio_device *pcs,
> > > + struct phylink_link_state *state) {
> > > + struct mii_bus *bus = pcs->bus;
> > > + int addr = pcs->addr;
> > > + int bmsr, lpa;
> > > +
> > > + bmsr = mdiobus_read(bus, addr, MII_BMSR);
> > > + lpa = mdiobus_read(bus, addr, MII_LPA);
> > > + if (bmsr < 0 || lpa < 0) {
> > > + state->link = false;
> > > + return;
> > > + }
> > > +
> > > + state->link = !!(bmsr & BMSR_LSTATUS);
> > > + state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
> > > + if (!state->link)
> > > + return;
> > > +
> > > + state->speed = SPEED_2500;
> > > + state->pause |= MLO_PAUSE_TX | MLO_PAUSE_RX;
> >
> > How do you know the other side is using pause frames, or is capable of
> > dealing
> > with them?
>
> Isn't this done by also looking into the PHY's pause frame bits and
> enabling pause frames in the MAC only when both the PCS and the PHY
> have flow enabled?
You are assuming that there is a PHY to read that information from.
There may not be a PHY - I have 2500base-X fibre links here, there is
no PHY to read that from, there is only the PCS - but this runs with
the configuration word present, so is not supported by this code (at
least at the moment.)
If there is a PHY, these bits will not be used anyway, so there's no
point setting them.
> Yep, will remove. I've gone through the documentation and the register
> should be initialized to 0x0001 when in SGMII mode
> (as done by phylink_mii_c22_pcs_config()).
Yep, that was actually written referring to the LX2160A documentation.
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