| Message ID | 20231019111459.1000218-3-o.rempel@pengutronix.de (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | fix forced link mode for KSZ886X switches | expand |
On Thu, Oct 19, 2023 at 01:14:59PM +0200, Oleksij Rempel wrote: > Address a link speed detection issue in KSZ886X PHY driver when in > forced link mode. Previously, link partners like "ASIX AX88772B" > with KSZ8873 could fall back to 10Mbit instead of configured 100Mbit. > > The issue arises as KSZ886X PHY continues sending Fast Link Pulses (FLPs) > even with autonegotiation off, misleading link partners in autoneg mode, > leading to incorrect link speed detection. > > Now, when autonegotiation is disabled, the driver sets the link state > forcefully using KSZ886X_CTRL_FORCE_LINK bit. This action, beyond just > disabling autonegotiation, makes the PHY state more reliably detected by > link partners using parallel detection, thus fixing the link speed > misconfiguration. > > With autonegotiation enabled, link state is not forced, allowing proper > autonegotiation process participation. > > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > --- Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> -----Original Message----- > From: Oleksij Rempel <o.rempel@pengutronix.de> > Sent: Thursday, October 19, 2023 4:45 PM > To: Woojung Huh - C21699 <Woojung.Huh@microchip.com>; > UNGLinuxDriver <UNGLinuxDriver@microchip.com>; Andrew Lunn > <andrew@lunn.ch>; Florian Fainelli <f.fainelli@gmail.com>; Vladimir Oltean > <olteanv@gmail.com>; David S. Miller <davem@davemloft.net>; Eric Dumazet > <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni > <pabeni@redhat.com>; Heiner Kallweit <hkallweit1@gmail.com> > Cc: Oleksij Rempel <o.rempel@pengutronix.de>; kernel@pengutronix.de; > linux-kernel@vger.kernel.org; Russell King <linux@armlinux.org.uk>; > netdev@vger.kernel.org; Alexander Stein <alexander.stein@ew.tq-group.com> > Subject: [PATCH net-next v3 2/2] net: phy: micrel: Fix forced link mode for > KSZ886X switches > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the > content is safe > > Address a link speed detection issue in KSZ886X PHY driver when in forced link > mode. Previously, link partners like "ASIX AX88772B" > with KSZ8873 could fall back to 10Mbit instead of configured 100Mbit. > > The issue arises as KSZ886X PHY continues sending Fast Link Pulses (FLPs) > even with autonegotiation off, misleading link partners in autoneg mode, > leading to incorrect link speed detection. > > Now, when autonegotiation is disabled, the driver sets the link state forcefully > using KSZ886X_CTRL_FORCE_LINK bit. This action, beyond just disabling > autonegotiation, makes the PHY state more reliably detected by link partners > using parallel detection, thus fixing the link speed misconfiguration. > > With autonegotiation enabled, link state is not forced, allowing proper > autonegotiation process participation. > > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> > --- > drivers/net/phy/micrel.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c index > 927d3d54658e..08e3915001c3 100644 > --- a/drivers/net/phy/micrel.c > +++ b/drivers/net/phy/micrel.c > @@ -1733,6 +1733,28 @@ static int ksz886x_config_aneg(struct phy_device > *phydev) > if (ret) > return ret; > > + if (phydev->autoneg != AUTONEG_ENABLE) { > + /* When autonegotation is disabled, we need to manually force > + * the link state. If we don't do this, the PHY will keep > + * sending Fast Link Pulses (FLPs) which are part of the > + * autonegotiation process. This is not desired when > + * autonegotiation is off. > + */ > + ret = phy_set_bits(phydev, MII_KSZPHY_CTRL, > + KSZ886X_CTRL_FORCE_LINK); > + if (ret) > + return ret; > + } else { > + /* If we had previously forced the link state, we need to > + * clear KSZ886X_CTRL_FORCE_LINK bit now. Otherwise, the PHY > + * will not perform autonegotiation. > + */ > + ret = phy_clear_bits(phydev, MII_KSZPHY_CTRL, > + KSZ886X_CTRL_FORCE_LINK); > + if (ret) > + return ret; > + } > + > /* The MDI-X configuration is automatically changed by the PHY after > * switching from autoneg off to on. So, take MDI-X configuration under > * own control and set it after autoneg configuration was done. > -- > 2.39.2 Reviewed-by: Divya Koppera <divya.koppera@microchip.com>
diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c index 927d3d54658e..08e3915001c3 100644 --- a/drivers/net/phy/micrel.c +++ b/drivers/net/phy/micrel.c @@ -1733,6 +1733,28 @@ static int ksz886x_config_aneg(struct phy_device *phydev) if (ret) return ret; + if (phydev->autoneg != AUTONEG_ENABLE) { + /* When autonegotation is disabled, we need to manually force + * the link state. If we don't do this, the PHY will keep + * sending Fast Link Pulses (FLPs) which are part of the + * autonegotiation process. This is not desired when + * autonegotiation is off. + */ + ret = phy_set_bits(phydev, MII_KSZPHY_CTRL, + KSZ886X_CTRL_FORCE_LINK); + if (ret) + return ret; + } else { + /* If we had previously forced the link state, we need to + * clear KSZ886X_CTRL_FORCE_LINK bit now. Otherwise, the PHY + * will not perform autonegotiation. + */ + ret = phy_clear_bits(phydev, MII_KSZPHY_CTRL, + KSZ886X_CTRL_FORCE_LINK); + if (ret) + return ret; + } + /* The MDI-X configuration is automatically changed by the PHY after * switching from autoneg off to on. So, take MDI-X configuration under * own control and set it after autoneg configuration was done.
Address a link speed detection issue in KSZ886X PHY driver when in forced link mode. Previously, link partners like "ASIX AX88772B" with KSZ8873 could fall back to 10Mbit instead of configured 100Mbit. The issue arises as KSZ886X PHY continues sending Fast Link Pulses (FLPs) even with autonegotiation off, misleading link partners in autoneg mode, leading to incorrect link speed detection. Now, when autonegotiation is disabled, the driver sets the link state forcefully using KSZ886X_CTRL_FORCE_LINK bit. This action, beyond just disabling autonegotiation, makes the PHY state more reliably detected by link partners using parallel detection, thus fixing the link speed misconfiguration. With autonegotiation enabled, link state is not forced, allowing proper autonegotiation process participation. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- drivers/net/phy/micrel.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)