lkml.org 
[lkml]   [2020]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [RFC net-next] net: phy: Add basic support for Synopsys XPCS using a PHY driver
    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

    \
     
     \ /
      Last update: 2020-01-13 15:51    [W:5.026 / U:0.024 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site