Merge branch 'net-fix-optical-sfp-failures'

Russell King says:

====================
net: fix optical SFP failures

A regression was reported back in April concerning pcs-lynx and 10G
optical SFPs. This patch series addresses that regression, and likely
similar unreported regressions.

These patches:
- Add phy_interface_weight() which will be used in the solution.
- Split out the code that determines the inband "type" for an
  interface mode.
- Clear the Autoneg bit in the advertising mask, or the Autoneg bit
  in the support mask and the entire advertising mask if the selected
  interface mode has no inband capabilties.

Tested with the mvpp2 patch posted earlier today.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: kuba-moo

drivers/net/phy/phylink.c

@@ -1016,6 +1016,42 @@ static void phylink_pcs_an_restart(struct phylink *pl)
 		pl->pcs->ops->pcs_an_restart(pl->pcs);
 }
 
+enum inband_type {
+	INBAND_NONE,
+	INBAND_CISCO_SGMII,
+	INBAND_BASEX,
+};
+
+static enum inband_type phylink_get_inband_type(phy_interface_t interface)
+{
+	switch (interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_QSGMII:
+	case PHY_INTERFACE_MODE_QUSGMII:
+	case PHY_INTERFACE_MODE_USXGMII:
+	case PHY_INTERFACE_MODE_10G_QXGMII:
+		/* These protocols are designed for use with a PHY which
+		 * communicates its negotiation result back to the MAC via
+		 * inband communication. Note: there exist PHYs that run
+		 * with SGMII but do not send the inband data.
+		 */
+		return INBAND_CISCO_SGMII;
+
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		/* 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
+		 * as well, but drivers may not support this, so may
+		 * need to override this.
+		 */
+		return INBAND_BASEX;
+
+	default:
+		return INBAND_NONE;
+	}
+}
+
 /**
  * phylink_pcs_neg_mode() - helper to determine PCS inband mode
  * @pl: a pointer to a &struct phylink returned from phylink_create()
@@ -1043,46 +1079,19 @@ static void phylink_pcs_neg_mode(struct phylink *pl, struct phylink_pcs *pcs,
 	unsigned int pcs_ib_caps = 0;
 	unsigned int phy_ib_caps = 0;
 	unsigned int neg_mode, mode;
-	enum {
-		INBAND_CISCO_SGMII,
-		INBAND_BASEX,
-	} type;
-
-	mode = pl->req_link_an_mode;
-
-	pl->phy_ib_mode = 0;
+	enum inband_type type;
 
-	switch (interface) {
-	case PHY_INTERFACE_MODE_SGMII:
-	case PHY_INTERFACE_MODE_QSGMII:
-	case PHY_INTERFACE_MODE_QUSGMII:
-	case PHY_INTERFACE_MODE_USXGMII:
-	case PHY_INTERFACE_MODE_10G_QXGMII:
-		/* These protocols are designed for use with a PHY which
-		 * communicates its negotiation result back to the MAC via
-		 * inband communication. Note: there exist PHYs that run
-		 * with SGMII but do not send the inband data.
-		 */
-		type = INBAND_CISCO_SGMII;
-		break;
-
-	case PHY_INTERFACE_MODE_1000BASEX:
-	case PHY_INTERFACE_MODE_2500BASEX:
-		/* 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
-		 * as well, but drivers may not support this, so may
-		 * need to override this.
-		 */
-		type = INBAND_BASEX;
-		break;
-
-	default:
+	type = phylink_get_inband_type(interface);
+	if (type == INBAND_NONE) {
 		pl->pcs_neg_mode = PHYLINK_PCS_NEG_NONE;
-		pl->act_link_an_mode = mode;
+		pl->act_link_an_mode = pl->req_link_an_mode;
 		return;
 	}
 
+	mode = pl->req_link_an_mode;
+
+	pl->phy_ib_mode = 0;
+
 	if (pcs)
 		pcs_ib_caps = phylink_pcs_inband_caps(pcs, interface);
 
@@ -3625,6 +3634,7 @@ static int phylink_sfp_config_optical(struct phylink *pl)
 {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(support);
 	struct phylink_link_state config;
+	enum inband_type inband_type;
 	phy_interface_t interface;
 	int ret;
 
@@ -3671,6 +3681,23 @@ static int phylink_sfp_config_optical(struct phylink *pl)
 	phylink_dbg(pl, "optical SFP: chosen %s interface\n",
 		    phy_modes(interface));
 
+	inband_type = phylink_get_inband_type(interface);
+	if (inband_type == INBAND_NONE) {
+		/* If this is the sole interface, and there is no inband
+		 * support, clear the advertising mask and Autoneg bit in
+		 * the support mask. Otherwise, just clear the Autoneg bit
+		 * in the advertising mask.
+		 */
+		if (phy_interface_weight(pl->sfp_interfaces) == 1) {
+			linkmode_clear_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
+					   pl->sfp_support);
+			linkmode_zero(config.advertising);
+		} else {
+			linkmode_clear_bit(ETHTOOL_LINK_MODE_Autoneg_BIT,
+					   config.advertising);
+		}
+	}
+
 	if (!phylink_validate_pcs_inband_autoneg(pl, interface,
 						 config.advertising)) {
 		phylink_err(pl, "autoneg setting not compatible with PCS");

include/linux/phy.h

@@ -169,6 +169,11 @@ static inline bool phy_interface_empty(const unsigned long *intf)
 	return bitmap_empty(intf, PHY_INTERFACE_MODE_MAX);
 }
 
+static inline unsigned int phy_interface_weight(const unsigned long *intf)
+{
+	return bitmap_weight(intf, PHY_INTERFACE_MODE_MAX);
+}
+
 static inline void phy_interface_and(unsigned long *dst, const unsigned long *a,
 				     const unsigned long *b)
 {