net: phylink: delay MAC configuration for copper SFP modules

Knowing whether we need to delay the MAC configuration because a module
may have a PHY is useful to phylink to allow NBASE-T modules to work on
systems supporting no more than 2.5G speeds.

This commit allows us to delay such configuration until after the PHY
has been probed by recording the parsed capabilities, and if the module
may have a PHY, doing no more until the module_start() notification is
called.  At that point, we either have a PHY, or we don't.

We move the PHY-based setup a little later, and use the PHYs support
capabilities rather than the EEPROM parsed capabilities to determine
whether we can support the PHY.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 43 insertions, 10 deletions

diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index eff0e54ef036..88afc98a2aa6 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -72,6 +72,9 @@ struct phylink {
 	bool mac_link_dropped;
 
 	struct sfp_bus *sfp_bus;
+	bool sfp_may_have_phy;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
+	u8 sfp_port;
 };
 
 #define phylink_printk(level, pl, fmt, ...) \
@@ -1686,7 +1689,7 @@ static void phylink_sfp_detach(void *upstream, struct sfp_bus *bus)
 	pl->netdev->sfp_bus = NULL;
 }
 
-static int phylink_sfp_config(struct phylink *pl, u8 mode, u8 port,
+static int phylink_sfp_config(struct phylink *pl, u8 mode,
 			      const unsigned long *supported,
 			      const unsigned long *advertising)
 {
@@ -1759,7 +1762,7 @@ static int phylink_sfp_config(struct phylink *pl, u8 mode, u8 port,
 			     phy_modes(config.interface));
 	}
 
-	pl->link_port = port;
+	pl->link_port = pl->sfp_port;
 
 	if (changed && !test_bit(PHYLINK_DISABLE_STOPPED,
 				 &pl->phylink_disable_state))
@@ -1772,15 +1775,20 @@ static int phylink_sfp_module_insert(void *upstream,
 				     const struct sfp_eeprom_id *id)
 {
 	struct phylink *pl = upstream;
-	__ETHTOOL_DECLARE_LINK_MODE_MASK(support) = { 0, };
-	u8 port;
+	unsigned long *support = pl->sfp_support;
 
 	ASSERT_RTNL();
 
+	linkmode_zero(support);
 	sfp_parse_support(pl->sfp_bus, id, support);
-	port = sfp_parse_port(pl->sfp_bus, id, support);
+	pl->sfp_port = sfp_parse_port(pl->sfp_bus, id, support);
 
-	return phylink_sfp_config(pl, MLO_AN_INBAND, port, support, support);
+	/* If this module may have a PHY connecting later, defer until later */
+	pl->sfp_may_have_phy = sfp_may_have_phy(pl->sfp_bus, id);
+	if (pl->sfp_may_have_phy)
+		return 0;
+
+	return phylink_sfp_config(pl, MLO_AN_INBAND, support, support);
 }
 
 static int phylink_sfp_module_start(void *upstream)
@@ -1788,10 +1796,19 @@ static int phylink_sfp_module_start(void *upstream)
 	struct phylink *pl = upstream;
 
 	/* If this SFP module has a PHY, start the PHY now. */
-	if (pl->phydev)
+	if (pl->phydev) {
 		phy_start(pl->phydev);
+		return 0;
+	}
 
-	return 0;
+	/* If the module may have a PHY but we didn't detect one we
+	 * need to configure the MAC here.
+	 */
+	if (!pl->sfp_may_have_phy)
+		return 0;
+
+	return phylink_sfp_config(pl, MLO_AN_INBAND,
+				  pl->sfp_support, pl->sfp_support);
 }
 
 static void phylink_sfp_module_stop(void *upstream)
@@ -1825,10 +1842,26 @@ static void phylink_sfp_link_up(void *upstream)
 static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
 {
 	struct phylink *pl = upstream;
-	phy_interface_t interface = pl->link_config.interface;
+	phy_interface_t interface;
 	int ret;
 
-	ret = phylink_attach_phy(pl, phy, pl->link_config.interface);
+	/*
+	 * This is the new way of dealing with flow control for PHYs,
+	 * as described by Timur Tabi in commit 529ed1275263 ("net: phy:
+	 * phy drivers should not set SUPPORTED_[Asym_]Pause") except
+	 * using our validate call to the MAC, we rely upon the MAC
+	 * clearing the bits from both supported and advertising fields.
+	 */
+	phy_support_asym_pause(phy);
+
+	/* Do the initial configuration */
+	ret = phylink_sfp_config(pl, MLO_AN_INBAND, phy->supported,
+				 phy->advertising);
+	if (ret < 0)
+		return ret;
+
+	interface = pl->link_config.interface;
+	ret = phylink_attach_phy(pl, phy, interface);
 	if (ret < 0)
 		return ret;