Messages in this thread | | | From | Vladimir Oltean <> | Date | Mon, 13 Jan 2020 16:50:18 +0200 | Subject | Re: [RFC net-next] net: phy: Add basic support for Synopsys XPCS using a PHY driver |
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Hi Russell,
On Mon, 13 Jan 2020 at 16:19, Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote: > > I've recently suggested a patch to phylink to add a generic helper to > read the state from a generic 802.3 clause 37 PCS, but I guess that > won't be sufficient for an XPCS. However, it should give some clues > if you're intending to use phylink. >
I don't think the PCS implementations out there are sufficiently similar to be driven by a unified driver, and at least nothing mandates that for now. Although the configuration interface is MDIO with registers quasi-compliant to C22 or C45, many times bits in BMCR/BMSR are not implemented, you can't typically achieve full functionality [ sometimes not at all ] without writing to some vendor-specific registers, there might be errata workarounds that need to be implemented through PCS writes, often the PCS driver needs to be correlated with a MMIO region corresponding to that SerDes lane for stuff such as eye parameters. The code duplication isn't even all that bad.
_But_ I am not sure how PHYLINK comes into play here. A PHY driver should work with the plain PHY library too. Dealing with clause 73 autoneg indicates to me that this is more than just a MAC PCS, therefore it shouldn't be tied in with PHYLINK.
Thanks, -Vladimir
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