net: add phylink support for PCS

index 805fec9f1c3f..9466c4e09290 100644
@@ -41,6 +41,7 @@ struct phylink {
 	/* private: */
 	struct net_device *netdev;
 	const struct phylink_mac_ops *mac_ops;
+	const struct phylink_pcs_ops *pcs_ops;
 	struct phylink_config *config;
 	struct device *dev;
 	unsigned int old_link_state:1;

@@ -398,11 +399,31 @@ static void phylink_mac_config_up(struct phylink *pl,
 		phylink_mac_config(pl, state);
 }
 
-static void phylink_mac_an_restart(struct phylink *pl)
+static void phylink_mac_pcs_an_restart(struct phylink *pl)
 {
 	if (pl->link_config.an_enabled &&
-	    phy_interface_mode_is_8023z(pl->link_config.interface))
-		pl->mac_ops->mac_an_restart(pl->config);
+	    phy_interface_mode_is_8023z(pl->link_config.interface)) {
+		if (pl->pcs_ops)
+			pl->pcs_ops->pcs_an_restart(pl->config);
+		else
+			pl->mac_ops->mac_an_restart(pl->config);
+	}
+}
+
+static void phylink_pcs_config(struct phylink *pl, bool force_restart,
+			       const struct phylink_link_state *state)
+{
+	bool restart = force_restart;
+
+	if (pl->pcs_ops && pl->pcs_ops->pcs_config(pl->config,
+						   pl->cur_link_an_mode,
+						   state))
+		restart = true;
+
+	phylink_mac_config(pl, state);
+
+	if (restart)
+		phylink_mac_pcs_an_restart(pl);
 }
 
 static void phylink_mac_pcs_get_state(struct phylink *pl,

@@ -418,7 +439,10 @@ static void phylink_mac_pcs_get_state(struct phylink *pl,
 	state->an_complete = 0;
 	state->link = 1;
 
-	pl->mac_ops->mac_pcs_get_state(pl->config, state);
+	if (pl->pcs_ops)
+		pl->pcs_ops->pcs_get_state(pl->config, state);
+	else
+		pl->mac_ops->mac_pcs_get_state(pl->config, state);
 }
 
 /* The fixed state is... fixed except for the link state,

@@ -436,7 +460,7 @@ static void phylink_get_fixed_state(struct phylink *pl,
 	phylink_resolve_flow(state);
 }
 
-static void phylink_mac_initial_config(struct phylink *pl)
+static void phylink_mac_initial_config(struct phylink *pl, bool force_restart)
 {
 	struct phylink_link_state link_state;
 

@@ -462,7 +486,7 @@ static void phylink_mac_initial_config(struct phylink *pl)
 	link_state.link = false;
 
 	phylink_apply_manual_flow(pl, &link_state);
-	phylink_mac_config(pl, &link_state);
+	phylink_pcs_config(pl, force_restart, &link_state);
 }
 
 static const char *phylink_pause_to_str(int pause)

@@ -479,12 +503,18 @@ static const char *phylink_pause_to_str(int pause)
 	}
 }
 
-static void phylink_mac_link_up(struct phylink *pl,
-				struct phylink_link_state link_state)
+static void phylink_link_up(struct phylink *pl,
+			    struct phylink_link_state link_state)
 {
 	struct net_device *ndev = pl->netdev;
 
 	pl->cur_interface = link_state.interface;
+
+	if (pl->pcs_ops && pl->pcs_ops->pcs_link_up)
+		pl->pcs_ops->pcs_link_up(pl->config, pl->cur_link_an_mode,
+					 pl->cur_interface,
+					 link_state.speed, link_state.duplex);
+
 	pl->mac_ops->mac_link_up(pl->config, pl->phydev,
 				 pl->cur_link_an_mode, pl->cur_interface,
 				 link_state.speed, link_state.duplex,

@@ -501,7 +531,7 @@ static void phylink_mac_link_up(struct phylink *pl,
 		     phylink_pause_to_str(link_state.pause));
 }
 
-static void phylink_mac_link_down(struct phylink *pl)
+static void phylink_link_down(struct phylink *pl)
 {
 	struct net_device *ndev = pl->netdev;
 

@@ -570,9 +600,9 @@ static void phylink_resolve(struct work_struct *w)
 	if (link_changed) {
 		pl->old_link_state = link_state.link;
 		if (!link_state.link)
-			phylink_mac_link_down(pl);
+			phylink_link_down(pl);
 		else
-			phylink_mac_link_up(pl, link_state);
+			phylink_link_up(pl, link_state);
 	}
 	if (!link_state.link && pl->mac_link_dropped) {
 		pl->mac_link_dropped = false;

@@ -719,6 +749,12 @@ struct phylink *phylink_create(struct phylink_config *config,
 }
 EXPORT_SYMBOL_GPL(phylink_create);
 
+void phylink_add_pcs(struct phylink *pl, const struct phylink_pcs_ops *ops)
+{
+	pl->pcs_ops = ops;
+}
+EXPORT_SYMBOL_GPL(phylink_add_pcs);
+
 /**
  * phylink_destroy() - cleanup and destroy the phylink instance
  * @pl: a pointer to a &struct phylink returned from phylink_create()

@@ -1055,14 +1091,12 @@ void phylink_start(struct phylink *pl)
 	/* Apply the link configuration to the MAC when starting. This allows
 	 * a fixed-link to start with the correct parameters, and also
 	 * ensures that we set the appropriate advertisement for Serdes links.
-	 */
-	phylink_mac_initial_config(pl);
-
-	/* Restart autonegotiation if using 802.3z to ensure that the link
+	 *
+	 * Restart autonegotiation if using 802.3z to ensure that the link
 	 * parameters are properly negotiated.  This is necessary for DSA
 	 * switches using 802.3z negotiation to ensure they see our modes.
 	 */
-	phylink_mac_an_restart(pl);
+	phylink_mac_initial_config(pl, true);
 
 	clear_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state);
 	phylink_run_resolve(pl);

@@ -1359,8 +1393,7 @@ int phylink_ethtool_ksettings_set(struct phylink *pl,
 			 * advertisement; the only thing we have is the pause
 			 * modes which can only come from a PHY.
 			 */
-			phylink_mac_config(pl, &pl->link_config);
-			phylink_mac_an_restart(pl);
+			phylink_pcs_config(pl, true, &pl->link_config);
 		}
 		mutex_unlock(&pl->state_mutex);
 	}

@@ -1388,7 +1421,7 @@ int phylink_ethtool_nway_reset(struct phylink *pl)
 
 	if (pl->phydev)
 		ret = phy_restart_aneg(pl->phydev);
-	phylink_mac_an_restart(pl);
+	phylink_mac_pcs_an_restart(pl);
 
 	return ret;
 }

@@ -1467,8 +1500,7 @@ int phylink_ethtool_set_pauseparam(struct phylink *pl,
 				   pause->tx_pause);
 	} else if (!test_bit(PHYLINK_DISABLE_STOPPED,
 			     &pl->phylink_disable_state)) {
-		phylink_mac_config(pl, &pl->link_config);
-		phylink_mac_an_restart(pl);
+		phylink_pcs_config(pl, true, &pl->link_config);
 	}
 	mutex_unlock(&pl->state_mutex);
 

@@ -1874,7 +1906,7 @@ static int phylink_sfp_config(struct phylink *pl, u8 mode,
 
 	if (changed && !test_bit(PHYLINK_DISABLE_STOPPED,
 				 &pl->phylink_disable_state))
-		phylink_mac_initial_config(pl);
+		phylink_mac_initial_config(pl, false);
 
 	return ret;
 }

index 8fa6df3b881b..dc27dd341ebd 100644
@@ -97,6 +97,16 @@ struct phylink_mac_ops {
 			    bool tx_pause, bool rx_pause);
 };
 
+struct phylink_pcs_ops {
+	void (*pcs_get_state)(struct phylink_config *config,
+			      struct phylink_link_state *state);
+	int (*pcs_config)(struct phylink_config *config, unsigned int mode,
+			  const struct phylink_link_state *state);
+	void (*pcs_an_restart)(struct phylink_config *config);
+	void (*pcs_link_up)(struct phylink_config *config, unsigned int mode,
+			    phy_interface_t interface, int speed, int duplex);
+};
+
 #if 0 /* For kernel-doc purposes only. */
 /**
  * validate - Validate and update the link configuration

@@ -273,6 +283,7 @@ void mac_link_up(struct phylink_config *config, struct phy_device *phy,
 struct phylink *phylink_create(struct phylink_config *, struct fwnode_handle *,
 			       phy_interface_t iface,
 			       const struct phylink_mac_ops *ops);
+void phylink_add_pcs(struct phylink *, const struct phylink_pcs_ops *ops);
 void phylink_destroy(struct phylink *);
 
 int phylink_connect_phy(struct phylink *, struct phy_device *);

index bff570f59d5c..805fec9f1c3f 100644
@@ -40,7 +40,7 @@ enum {
 struct phylink {
 	/* private: */
 	struct net_device *netdev;
-	const struct phylink_mac_ops *ops;
+	const struct phylink_mac_ops *mac_ops;
 	struct phylink_config *config;
 	struct device *dev;
 	unsigned int old_link_state:1;

@@ -154,7 +154,7 @@ static const char *phylink_an_mode_str(unsigned int mode)
 static int phylink_validate(struct phylink *pl, unsigned long *supported,
 			    struct phylink_link_state *state)
 {
-	pl->ops->validate(pl->config, supported, state);
+	pl->mac_ops->validate(pl->config, supported, state);
 
 	return phylink_is_empty_linkmode(supported) ? -EINVAL : 0;
 }

@@ -388,7 +388,7 @@ static void phylink_mac_config(struct phylink *pl,
 		    __ETHTOOL_LINK_MODE_MASK_NBITS, state->advertising,
 		    state->pause, state->link, state->an_enabled);
 
-	pl->ops->mac_config(pl->config, pl->cur_link_an_mode, state);
+	pl->mac_ops->mac_config(pl->config, pl->cur_link_an_mode, state);
 }
 
 static void phylink_mac_config_up(struct phylink *pl,

@@ -402,7 +402,7 @@ static void phylink_mac_an_restart(struct phylink *pl)
 {
 	if (pl->link_config.an_enabled &&
 	    phy_interface_mode_is_8023z(pl->link_config.interface))
-		pl->ops->mac_an_restart(pl->config);
+		pl->mac_ops->mac_an_restart(pl->config);
 }
 
 static void phylink_mac_pcs_get_state(struct phylink *pl,

@@ -418,7 +418,7 @@ static void phylink_mac_pcs_get_state(struct phylink *pl,
 	state->an_complete = 0;
 	state->link = 1;
 
-	pl->ops->mac_pcs_get_state(pl->config, state);
+	pl->mac_ops->mac_pcs_get_state(pl->config, state);
 }
 
 /* The fixed state is... fixed except for the link state,

@@ -485,11 +485,11 @@ static void phylink_mac_link_up(struct phylink *pl,
 	struct net_device *ndev = pl->netdev;
 
 	pl->cur_interface = link_state.interface;
-	pl->ops->mac_link_up(pl->config, pl->phydev,
-			     pl->cur_link_an_mode, pl->cur_interface,
-			     link_state.speed, link_state.duplex,
-			     !!(link_state.pause & MLO_PAUSE_TX),
-			     !!(link_state.pause & MLO_PAUSE_RX));
+	pl->mac_ops->mac_link_up(pl->config, pl->phydev,
+				 pl->cur_link_an_mode, pl->cur_interface,
+				 link_state.speed, link_state.duplex,
+				 !!(link_state.pause & MLO_PAUSE_TX),
+				 !!(link_state.pause & MLO_PAUSE_RX));
 
 	if (ndev)
 		netif_carrier_on(ndev);

@@ -507,8 +507,8 @@ static void phylink_mac_link_down(struct phylink *pl)
 
 	if (ndev)
 		netif_carrier_off(ndev);
-	pl->ops->mac_link_down(pl->config, pl->cur_link_an_mode,
-			       pl->cur_interface);
+	pl->mac_ops->mac_link_down(pl->config, pl->cur_link_an_mode,
+				   pl->cur_interface);
 	phylink_info(pl, "Link is Down\n");
 }
 

@@ -639,7 +639,7 @@ static int phylink_register_sfp(struct phylink *pl,
  * @fwnode: a pointer to a &struct fwnode_handle describing the network
  *	interface
  * @iface: the desired link mode defined by &typedef phy_interface_t
- * @ops: a pointer to a &struct phylink_mac_ops for the MAC.
+ * @mac_ops: a pointer to a &struct phylink_mac_ops for the MAC.
  *
  * Create a new phylink instance, and parse the link parameters found in @np.
  * This will parse in-band modes, fixed-link or SFP configuration.

@@ -652,7 +652,7 @@ static int phylink_register_sfp(struct phylink *pl,
 struct phylink *phylink_create(struct phylink_config *config,
 			       struct fwnode_handle *fwnode,
 			       phy_interface_t iface,
-			       const struct phylink_mac_ops *ops)
+			       const struct phylink_mac_ops *mac_ops)
 {
 	struct phylink *pl;
 	int ret;

@@ -685,7 +685,7 @@ struct phylink *phylink_create(struct phylink_config *config,
 	pl->link_config.speed = SPEED_UNKNOWN;
 	pl->link_config.duplex = DUPLEX_UNKNOWN;
 	pl->link_config.an_enabled = true;
-	pl->ops = ops;
+	pl->mac_ops = mac_ops;
 	__set_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state);
 	timer_setup(&pl->link_poll, phylink_fixed_poll, 0);
 

index 7ca427c46d9f..bff570f59d5c 100644
@@ -2247,4 +2247,34 @@ void phylink_mii_c22_pcs_an_restart(struct mdio_device *pcs)
 }
 EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_an_restart);
 
+#define C45_ADDR(d,a)	(MII_ADDR_C45 | (d) << 16 | (a))
+void phylink_mii_c45_pcs_get_state(struct mdio_device *pcs,
+				   struct phylink_link_state *state)
+{
+	struct mii_bus *bus = pcs->bus;
+	int addr = pcs->addr;
+	int stat;
+
+	stat = mdiobus_read(bus, addr, C45_ADDR(MDIO_MMD_PCS, MDIO_STAT1));
+	if (stat < 0) {
+		state->link = false;
+		return;
+	}
+
+	state->link = !!(stat & MDIO_STAT1_LSTATUS);
+	if (!state->link)
+		return;
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_10GBASER:
+		state->speed = SPEED_10000;
+		state->duplex = DUPLEX_FULL;
+		break;
+
+	default:
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(phylink_mii_c45_pcs_get_state);
+
 MODULE_LICENSE("GPL v2");

index de591c2fb37e..8fa6df3b881b 100644
@@ -323,4 +323,6 @@ int phylink_mii_c22_pcs_set_advertisement(struct mdio_device *pcs,
 					const struct phylink_link_state *state);
 void phylink_mii_c22_pcs_an_restart(struct mdio_device *pcs);
 
+void phylink_mii_c45_pcs_get_state(struct mdio_device *pcs,
+				   struct phylink_link_state *state);
 #endif

index 3ab9ca7614d1..b33d1e793686 100644
@@ -824,6 +824,38 @@ int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 }
 EXPORT_SYMBOL(__mdiobus_write);
 
+/**
+ * __mdiobus_modify_changed - Unlocked version of the mdiobus_modify function
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to modify
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Read, modify, and if any change, write the register value back to the
+ * device. Any error returns a negative number.
+ *
+ * NOTE: MUST NOT be called from interrupt context.
+ */
+int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
+			     u16 mask, u16 set)
+{
+	int new, ret;
+
+	ret = __mdiobus_read(bus, addr, regnum);
+	if (ret < 0)
+		return ret;
+
+	new = (ret & ~mask) | set;
+	if (new == ret)
+		return 0;
+
+	ret = __mdiobus_write(bus, addr, regnum, new);
+
+	return ret < 0 ? ret : 1;
+}
+EXPORT_SYMBOL_GPL(__mdiobus_modify_changed);
+
 /**
  * mdiobus_read_nested - Nested version of the mdiobus_read function
  * @bus: the mii_bus struct

@@ -928,6 +960,29 @@ int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
 }
 EXPORT_SYMBOL(mdiobus_write);
 
+/**
+ * mdiobus_modify - Convenience function for modifying a given mdio device
+ *	register
+ * @bus: the mii_bus struct
+ * @addr: the phy address
+ * @regnum: register number to write
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ */
+int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask, u16 set)
+{
+	int err;
+
+	BUG_ON(in_interrupt());
+
+	mutex_lock(&bus->mdio_lock);
+	err = __mdiobus_modify_changed(bus, addr, regnum, mask, set);
+	mutex_unlock(&bus->mdio_lock);
+
+	return err < 0 ? err : 0;
+}
+EXPORT_SYMBOL_GPL(mdiobus_modify);
+
 /**
  * mdio_bus_match - determine if given MDIO driver supports the given
  *		    MDIO device

index e083e7a76ada..94cd85b1e49b 100644
@@ -488,37 +488,6 @@ int phy_write_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val)
 }
 EXPORT_SYMBOL(phy_write_mmd);
 
-/**
- * __phy_modify_changed() - Convenience function for modifying a PHY register
- * @phydev: a pointer to a &struct phy_device
- * @regnum: register number
- * @mask: bit mask of bits to clear
- * @set: bit mask of bits to set
- *
- * Unlocked helper function which allows a PHY register to be modified as
- * new register value = (old register value & ~mask) | set
- *
- * Returns negative errno, 0 if there was no change, and 1 in case of change
- */
-int __phy_modify_changed(struct phy_device *phydev, u32 regnum, u16 mask,
-			 u16 set)
-{
-	int new, ret;
-
-	ret = __phy_read(phydev, regnum);
-	if (ret < 0)
-		return ret;
-
-	new = (ret & ~mask) | set;
-	if (new == ret)
-		return 0;
-
-	ret = __phy_write(phydev, regnum, new);
-
-	return ret < 0 ? ret : 1;
-}
-EXPORT_SYMBOL_GPL(__phy_modify_changed);
-
 /**
  * phy_modify_changed - Function for modifying a PHY register
  * @phydev: the phy_device struct

index a7604248777b..917e4bb2ed71 100644
@@ -316,11 +316,15 @@ static inline void mii_10gbt_stat_mod_linkmode_lpa_t(unsigned long *advertising,
 
 int __mdiobus_read(struct mii_bus *bus, int addr, u32 regnum);
 int __mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val);
+int __mdiobus_modify_changed(struct mii_bus *bus, int addr, u32 regnum,
+			     u16 mask, u16 set);
 
 int mdiobus_read(struct mii_bus *bus, int addr, u32 regnum);
 int mdiobus_read_nested(struct mii_bus *bus, int addr, u32 regnum);
 int mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val);
 int mdiobus_write_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val);
+int mdiobus_modify(struct mii_bus *bus, int addr, u32 regnum, u16 mask,
+		   u16 set);
 
 int mdiobus_register_device(struct mdio_device *mdiodev);
 int mdiobus_unregister_device(struct mdio_device *mdiodev);

index 7a08023bdbc5..c56166487036 100644
@@ -750,6 +750,25 @@ static inline int __phy_write(struct phy_device *phydev, u32 regnum, u16 val)
 			       val);
 }
 
+/**
+ * __phy_modify_changed() - Convenience function for modifying a PHY register
+ * @phydev: a pointer to a &struct phy_device
+ * @regnum: register number
+ * @mask: bit mask of bits to clear
+ * @set: bit mask of bits to set
+ *
+ * Unlocked helper function which allows a PHY register to be modified as
+ * new register value = (old register value & ~mask) | set
+ *
+ * Returns negative errno, 0 if there was no change, and 1 in case of change
+ */
+static inline int __phy_modify_changed(struct phy_device *phydev, u32 regnum,
+				       u16 mask, u16 set)
+{
+	return __mdiobus_modify_changed(phydev->mdio.bus, phydev->mdio.addr,
+					regnum, mask, set);
+}
+
 /**
  * phy_read_mmd - Convenience function for reading a register
  * from an MMD on a given PHY.

index a8eeaabb2d18..7ca427c46d9f 100644
@@ -2041,4 +2041,210 @@ void phylink_helper_basex_speed(struct phylink_link_state *state)
 }
 EXPORT_SYMBOL_GPL(phylink_helper_basex_speed);
 
+static void phylink_decode_c37_word(struct phylink_link_state *state,
+				    uint16_t config_reg, int speed)
+{
+	bool tx_pause, rx_pause;
+	int fd_bit;
+
+	if (speed == SPEED_2500)
+		fd_bit = ETHTOOL_LINK_MODE_2500baseX_Full_BIT;
+	else
+		fd_bit = ETHTOOL_LINK_MODE_1000baseX_Full_BIT;
+
+	mii_lpa_mod_linkmode_x(state->lp_advertising, config_reg, fd_bit);
+
+	if (linkmode_test_bit(fd_bit, state->advertising) &&
+	    linkmode_test_bit(fd_bit, state->lp_advertising)) {
+		state->speed = speed;
+		state->duplex = DUPLEX_FULL;
+	} else {
+		/* negotiation failure */
+		state->link = false;
+	}
+
+	linkmode_resolve_pause(state->advertising, state->lp_advertising,
+			       &tx_pause, &rx_pause);
+
+	if (tx_pause)
+		state->pause |= MLO_PAUSE_TX;
+	if (rx_pause)
+		state->pause |= MLO_PAUSE_RX;
+}
+
+static void phylink_decode_sgmii_word(struct phylink_link_state *state,
+				      uint16_t config_reg)
+{
+	if (!(config_reg & LPA_SGMII_LINK)) {
+		state->link = false;
+		return;
+	}
+
+	switch (config_reg & LPA_SGMII_SPD_MASK) {
+	case LPA_SGMII_10:
+		state->speed = SPEED_10;
+		break;
+	case LPA_SGMII_100:
+		state->speed = SPEED_100;
+		break;
+	case LPA_SGMII_1000:
+		state->speed = SPEED_1000;
+		break;
+	default:
+		state->link = false;
+		return;
+	}
+	if (config_reg & LPA_SGMII_FULL_DUPLEX)
+		state->duplex = DUPLEX_FULL;
+	else
+		state->duplex = DUPLEX_HALF;
+}
+
+/**
+ * phylink_mii_c22_pcs_get_state() - read the MAC PCS state
+ * @pcs: a pointer to a &struct mdio_device.
+ * @state: a pointer to a &struct phylink_link_state.
+ *
+ * Helper for MAC PCS supporting the 802.3 clause 22 register set for
+ * clause 37 negotiation and/or SGMII control.
+ *
+ * Read the MAC PCS state from the MII device configured in @config and
+ * parse the Clause 37 or Cisco SGMII link partner negotiation word into
+ * the phylink @state structure. This is suitable to be directly plugged
+ * into the mac_pcs_get_state() member of the struct phylink_mac_ops
+ * structure.
+ */
+void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,
+				   struct phylink_link_state *state)
+{
+	struct mii_bus *bus = pcs->bus;
+	int addr = pcs->addr;
+	int bmsr, lpa;
+
+	bmsr = mdiobus_read(bus, addr, MII_BMSR);
+	lpa = mdiobus_read(bus, addr, MII_LPA);
+	if (bmsr < 0 || lpa < 0) {
+		state->link = false;
+		return;
+	}
+
+	state->link = !!(bmsr & BMSR_LSTATUS);
+	state->an_complete = !!(bmsr & BMSR_ANEGCOMPLETE);
+	if (!state->link)
+		return;
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_1000BASEX:
+		phylink_decode_c37_word(state, lpa, SPEED_1000);
+		break;
+
+	case PHY_INTERFACE_MODE_2500BASEX:
+		phylink_decode_c37_word(state, lpa, SPEED_2500);
+		break;
+
+	case PHY_INTERFACE_MODE_SGMII:
+		phylink_decode_sgmii_word(state, lpa);
+		break;
+
+	default:
+		state->link = false;
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_get_state);
+
+/**
+ * phylink_mii_c22_pcs_set_advertisement() - configure the clause 37 PCS
+ *	advertisement
+ * @pcs: a pointer to a &struct mdio_device.
+ * @state: a pointer to the state being configured.
+ *
+ * Helper for MAC PCS supporting the 802.3 clause 22 register set for
+ * clause 37 negotiation and/or SGMII control.
+ *
+ * Configure the clause 37 PCS advertisement as specified by @state. This
+ * does not trigger a renegotiation; phylink will do that via the
+ * mac_an_restart() method of the struct phylink_mac_ops structure.
+ *
+ * Returns negative error code on failure to configure the advertisement,
+ * zero if no change has been made, or one if the advertisement has changed.
+ */
+int phylink_mii_c22_pcs_set_advertisement(struct mdio_device *pcs,
+					const struct phylink_link_state *state)
+{
+	struct mii_bus *bus = pcs->bus;
+	int addr = pcs->addr;
+	int val, ret;
+	u16 adv;
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		adv = ADVERTISE_1000XFULL;
+		if (linkmode_test_bit(ETHTOOL_LINK_MODE_Pause_BIT,
+				      state->advertising))
+			adv |= ADVERTISE_1000XPAUSE;
+		if (linkmode_test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
+				      state->advertising))
+			adv |= ADVERTISE_1000XPSE_ASYM;
+
+		val = mdiobus_read(bus, addr, MII_ADVERTISE);
+		if (val < 0)
+			return val;
+
+		if (val == adv)
+			return 0;
+
+		ret = mdiobus_write(bus, addr, MII_ADVERTISE, adv);
+		if (ret < 0)
+			return ret;
+
+		return 1;
+
+	case PHY_INTERFACE_MODE_SGMII:
+		val = mdiobus_read(bus, addr, MII_ADVERTISE);
+		if (val < 0)
+			return val;
+
+		if (val == 0x0001)
+			return 0;
+
+		ret = mdiobus_write(bus, addr, MII_ADVERTISE, 0x0001);
+		if (ret < 0)
+			return ret;
+
+		return 1;
+
+	default:
+		/* Nothing to do for other modes */
+		return 0;
+	}
+}
+EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_set_advertisement);
+
+/**
+ * phylink_mii_c22_pcs_an_restart() - restart 802.3z autonegotiation
+ * @pcs: a pointer to a &struct mdio_device.
+ *
+ * Helper for MAC PCS supporting the 802.3 clause 22 register set for
+ * clause 37 negotiation.
+ *
+ * Restart the clause 37 negotiation with the link partner. This is
+ * suitable to be directly plugged into the mac_pcs_get_state() member
+ * of the struct phylink_mac_ops structure.
+ */
+void phylink_mii_c22_pcs_an_restart(struct mdio_device *pcs)
+{
+	struct mii_bus *bus = pcs->bus;
+	int val, addr = pcs->addr;
+
+	val = mdiobus_read(bus, addr, MII_BMCR);
+	if (val >= 0) {
+		val |= BMCR_ANRESTART;
+
+		mdiobus_write(bus, addr, MII_BMCR, val);
+	}
+}
+EXPORT_SYMBOL_GPL(phylink_mii_c22_pcs_an_restart);
+
 MODULE_LICENSE("GPL v2");

index 2180eb1aa254..de591c2fb37e 100644
@@ -317,4 +317,10 @@ int phylink_mii_ioctl(struct phylink *, struct ifreq *, int);
 void phylink_set_port_modes(unsigned long *bits);
 void phylink_helper_basex_speed(struct phylink_link_state *state);
 
+void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,
+				   struct phylink_link_state *state);
+int phylink_mii_c22_pcs_set_advertisement(struct mdio_device *pcs,
+					const struct phylink_link_state *state);
+void phylink_mii_c22_pcs_an_restart(struct mdio_device *pcs);
+
 #endif

index 0b9c3beda345..90f9b4e1ba27 100644
@@ -134,11 +134,16 @@
 /* MAC and PHY tx_config_Reg[15:0] for SGMII in-band auto-negotiation.*/
 #define ADVERTISE_SGMII		0x0001	/* MAC can do SGMII            */
 #define LPA_SGMII		0x0001	/* PHY can do SGMII            */
+#define LPA_SGMII_SPD_MASK	0x0c00	/* SGMII speed mask            */
+#define LPA_SGMII_FULL_DUPLEX	0x1000	/* SGMII full duplex           */
 #define LPA_SGMII_DPX_SPD_MASK	0x1C00	/* SGMII duplex and speed bits */
+#define LPA_SGMII_10		0x0000	/* 10Mbps                      */
 #define LPA_SGMII_10HALF	0x0000	/* Can do 10mbps half-duplex   */
 #define LPA_SGMII_10FULL	0x1000	/* Can do 10mbps full-duplex   */
+#define LPA_SGMII_100		0x0400	/* 100Mbps                     */
 #define LPA_SGMII_100HALF	0x0400	/* Can do 100mbps half-duplex  */
 #define LPA_SGMII_100FULL	0x1400	/* Can do 100mbps full-duplex  */
+#define LPA_SGMII_1000		0x0800	/* 1000Mbps                    */
 #define LPA_SGMII_1000HALF	0x0800	/* Can do 1000mbps half-duplex */
 #define LPA_SGMII_1000FULL	0x1800	/* Can do 1000mbps full-duplex */
 #define LPA_SGMII_LINK		0x8000	/* PHY link with copper-side partner */