From ffb89801a541ac368d87b144a4f264cbcd8642ea Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 12 Feb 2021 19:01:52 +0200 Subject: [PATCH] net: phylink: explicitly configure in-band autoneg for PHYs that support it Currently Linux has no control over whether a MAC-to-PHY interface uses in-band signaling or not, even though phylink has the managed = "in-band-status"; property which denotes that the MAC expects in-band signaling to be used. The problem is really that if the in-band signaling is configurable in both the PHY and the MAC, there is a risk that they are out of sync unless phylink manages them both. Most if not all in-band autoneg state machines follow IEEE 802.3 clause 37, which means that they will not change the operating mode of the SERDES lane from control to data mode unless in-band AN completed successfully. Therefore traffic will not work. It is particularly unpleasant that currently, we assume that PHYs which have configurable in-band AN come pre-configured from a prior boot stage such as U-Boot, because once the bootloader changes, all bets are off. Let's introduce a new PHY driver method for configuring in-band autoneg, and make phylink be its first user. The main PHY library does not call phy_config_inband_autoneg, because it does not know what to configure it to. Presumably, non-phylink drivers can also call phy_config_inband_autoneg individually. Signed-off-by: Vladimir Oltean --- drivers/net/phy/phy.c | 12 ++++++++++++ drivers/net/phy/phylink.c | 8 ++++++++ include/linux/phy.h | 8 ++++++++ 3 files changed, 28 insertions(+) diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index 28ddaad721ed..7da6bdb3af82 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -766,6 +766,18 @@ static int phy_check_link_status(struct phy_device *phydev) return 0; } +int phy_config_inband_aneg(struct phy_device *phydev, bool enabled) +{ + if (!phydev->drv) + return -EIO; + + if (!phydev->drv->config_inband_aneg) + return -EOPNOTSUPP; + + return phydev->drv->config_inband_aneg(phydev, enabled); +} +EXPORT_SYMBOL(phy_config_inband_aneg); + /** * phy_start_aneg - start auto-negotiation for this PHY device * @phydev: the phy_device struct diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c index 6072e87ed6c3..0cd94633a75f 100644 --- a/drivers/net/phy/phylink.c +++ b/drivers/net/phy/phylink.c @@ -978,6 +978,14 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy, return ret; } + ret = phy_config_inband_aneg(phy, + (pl->cur_link_an_mode == MLO_AN_INBAND)); + if (ret && ret != -EOPNOTSUPP) { + phylink_warn(pl, "failed to configure PHY in-band autoneg: %d\n", + ret); + return ret; + } + phy->phylink = pl; phy->phy_link_change = phylink_phy_change; diff --git a/include/linux/phy.h b/include/linux/phy.h index ce888ed2c3c4..152a47a3f0cf 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -742,6 +742,13 @@ struct phy_driver { */ int (*config_aneg)(struct phy_device *phydev); + /** + * @config_inband_aneg: Enable or disable in-band auto-negotiation for + * the system-side interface if the PHY operates in a mode that + * requires it: (Q)SGMII, USXGMII, 1000Base-X, etc. + */ + int (*config_inband_aneg)(struct phy_device *phydev, bool enabled); + /** @aneg_done: Determines the auto negotiation result */ int (*aneg_done)(struct phy_device *phydev); @@ -1396,6 +1403,7 @@ void phy_detach(struct phy_device *phydev); void phy_start(struct phy_device *phydev); void phy_stop(struct phy_device *phydev); int phy_start_aneg(struct phy_device *phydev); +int phy_config_inband_aneg(struct phy_device *phydev, bool enabled); int phy_aneg_done(struct phy_device *phydev); int phy_speed_down(struct phy_device *phydev, bool sync); int phy_speed_up(struct phy_device *phydev); -- 2.17.1