Hi Russell, On Sat, Sep 23, 2023 at 04:48:57PM +0300, Vladimir Oltean wrote: > Some phylink and phylib based systems might want to operate on backplane > media types ("K" in the name), and thus, picking a phy_interface_t for > them becomes a challenge. > > phy_interface_t is a description of the connection between the MAC and > the PHY, or if a MAC-side PCS is present, the connection between that > and the next link segment (which can be remote). > > A MAC-side PCS is so far considered to be a PCS handling link modes with > optional C37 autoneg. But C73 autoneg (for backplanes and SFP28 modules) > is not at the same level in the OSI layering, so that existing model may > or may not apply. > > (a) If we say that the PCS is MAC-side for C73 modes as well, the > implication seems to be that the phy-mode should be one of > PHY_INTERFACE_MODE_10GBASEKR, PHY_INTERFACE_MODE_1000BASEKX, etc. > Similar to PHY_INTERFACE_MODE_1000BASEX which imitates the link mode > ETHTOOL_LINK_MODE_1000baseX_Full_BIT. > > (b) If we say that the PCS is not MAC-side, but rather that the > phylink_pcs represents an entire non-phylib backplane PHY which may > negotiate one of many link modes (like a copper phylib PHY), then > the phy-mode should probably be one of PHY_INTERFACE_MODE_XGMII, > XLGMII etc. Or rather, because there is no MII pinout per se and the > backplane PHY / phylink_pcs is internal, we can also use > PHY_INTERFACE_MODE_INTERNAL. > > The trouble with (a), in my opinion, is that if we let the phy_interface_t > follow the link mode like in the case of Base-X fiber modes, we have to > consider the fact that C73 PHYs can advertise multiple link modes, so > the phy_interface_t selection will be arbitrary, and any phy_interface_t > selection will have to leave in the "supported" and "advertised" masks > of link modes all the other backplane modes. This may be hard to justify. > > That is the reasoning based on which I selected this phy-mode to > describe the setup in Layerscape SoCs which have integrated backplane > autoneg support. The changes in phylink permit the managed = > "in-band-status" fwnode property to be extended for C73 autoneg, which > is then controllable through ethtool. With phy-mode = "internal" in an > in-band autoneg mode, we advertise all backplane link modes. The list is > not exhaustive and may be extended in the future. > > Link: https://lore.kernel.org/netdev/ZOXlpkbcAZ4okric@xxxxxxxxxxxxxxxxxxxxx/ > Link: https://lore.kernel.org/netdev/ZGIkGmyL8yL1q1zp@xxxxxxxxxxxxxxxxxxxxx/ > Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx> > --- > v1->v2: patch is new > > drivers/net/phy/phylink.c | 19 ++++++++++++++++++- > include/linux/phylink.h | 1 + > 2 files changed, 19 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c > index 548130d77302..88ace7e203c3 100644 > --- a/drivers/net/phy/phylink.c > +++ b/drivers/net/phy/phylink.c > @@ -972,6 +972,21 @@ static int phylink_parse_mode(struct phylink *pl, > phylink_set(pl->supported, 100000baseDR2_Full); > break; > > + case PHY_INTERFACE_MODE_INTERNAL: > + phylink_set(pl->supported, 1000baseKX_Full); > + phylink_set(pl->supported, 10000baseKX4_Full); > + phylink_set(pl->supported, 10000baseKR_Full); > + phylink_set(pl->supported, 25000baseCR_Full); > + phylink_set(pl->supported, 25000baseKR_Full); > + phylink_set(pl->supported, 25000baseCR_S_Full); > + phylink_set(pl->supported, 25000baseKR_S_Full); > + phylink_set(pl->supported, 40000baseKR4_Full); > + phylink_set(pl->supported, 50000baseKR2_Full); > + phylink_set(pl->supported, 50000baseKR_Full); > + phylink_set(pl->supported, 100000baseKR4_Full); > + phylink_set(pl->supported, 100000baseKR2_Full); > + break; > + > default: > phylink_err(pl, > "incorrect link mode %s for in-band status\n", > @@ -1109,7 +1124,9 @@ static void phylink_mac_config(struct phylink *pl, > > static bool phylink_pcs_handles_an(phy_interface_t iface, unsigned int mode) > { > - return phy_interface_mode_is_8023z(iface) && phylink_autoneg_inband(mode); > + return (phy_interface_mode_is_8023z(iface) || > + iface == PHY_INTERFACE_MODE_INTERNAL) && > + phylink_autoneg_inband(mode); > } > > static void phylink_pcs_an_restart(struct phylink *pl) > diff --git a/include/linux/phylink.h b/include/linux/phylink.h > index 2b886ea654bb..7e8e26001587 100644 > --- a/include/linux/phylink.h > +++ b/include/linux/phylink.h > @@ -141,6 +141,7 @@ static inline unsigned int phylink_pcs_neg_mode(unsigned int mode, > > case PHY_INTERFACE_MODE_1000BASEX: > case PHY_INTERFACE_MODE_2500BASEX: > + case PHY_INTERFACE_MODE_INTERNAL: > /* 1000base-X is designed for use media-side for Fibre > * connections, and thus the Autoneg bit needs to be > * taken into account. We also do this for 2500base-X > -- > 2.34.1 > What do you think about this change?