From: Russell King <rmk+kernel@armlinux.org.uk>
Date: Wed, 11 Dec 2019 10:56:30 +0000
Subject: net: phylink: support Clause 45 PHYs on SFP+ modules
Patch-mainline: v5.6-rc1
Git-commit: e45d1f5288b81e77eb87288ae2d0a0d00e0989d3
References: bsc#1176447

Some SFP+ modules have Clause 45 PHYs embedded on them, which need a
little more handling in order to ensure that they are correctly setup,
as they switch the PHY link mode according to the negotiated speed.

With Clause 22 PHYs, we assumed that they would operate in SGMII mode,
but this assumption is now false.  Adapt phylink to support Clause 45
PHYs on SFP+ modules.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/phy/phylink.c |   21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -713,7 +713,8 @@ static void phylink_phy_change(struct ph
 		    phy_duplex_to_str(phydev->duplex));
 }
 
-static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy)
+static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
+			       phy_interface_t interface)
 {
 	struct phylink_link_state config;
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);
@@ -731,7 +732,7 @@ static int phylink_bringup_phy(struct ph
 	memset(&config, 0, sizeof(config));
 	linkmode_copy(supported, phy->supported);
 	linkmode_copy(config.advertising, phy->advertising);
-	config.interface = pl->link_config.interface;
+	config.interface = interface;
 
 	ret = phylink_validate(pl, supported, &config);
 	if (ret)
@@ -747,6 +748,7 @@ static int phylink_bringup_phy(struct ph
 	mutex_lock(&phy->lock);
 	mutex_lock(&pl->state_mutex);
 	pl->phydev = phy;
+	pl->phy_state.interface = interface;
 	linkmode_copy(pl->supported, supported);
 	linkmode_copy(pl->link_config.advertising, config.advertising);
 
@@ -809,7 +811,7 @@ int phylink_connect_phy(struct phylink *
 	if (ret < 0)
 		return ret;
 
-	ret = phylink_bringup_phy(pl, phy);
+	ret = phylink_bringup_phy(pl, phy, pl->link_config.interface);
 	if (ret)
 		phy_detach(phy);
 
@@ -862,7 +864,7 @@ int phylink_of_phy_connect(struct phylin
 	if (!phy_dev)
 		return -ENODEV;
 
-	ret = phylink_bringup_phy(pl, phy_dev);
+	ret = phylink_bringup_phy(pl, phy_dev, pl->link_config.interface);
 	if (ret)
 		phy_detach(phy_dev);
 
@@ -1814,13 +1816,22 @@ static void phylink_sfp_link_up(void *up
 static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
 {
 	struct phylink *pl = upstream;
+	phy_interface_t interface = pl->link_config.interface;
 	int ret;
 
 	ret = phylink_attach_phy(pl, phy, pl->link_config.interface);
 	if (ret < 0)
 		return ret;
 
-	ret = phylink_bringup_phy(pl, phy);
+	/* Clause 45 PHYs switch their Serdes lane between several different
+	 * modes, normally 10GBASE-R, SGMII. Some use 2500BASE-X for 2.5G
+	 * speeds.  We really need to know which interface modes the PHY and
+	 * MAC supports to properly work out which linkmodes can be supported.
+	 */
+	if (phy->is_c45)
+		interface = PHY_INTERFACE_MODE_NA;
+
+	ret = phylink_bringup_phy(pl, phy, interface);
 	if (ret)
 		phy_detach(phy);