diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 8406412..96d9e1f 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -62,6 +62,27 @@ const char *phy_duplex_to_str(unsigned int duplex)
 }
 EXPORT_SYMBOL_GPL(phy_duplex_to_str);
 
+/**
+ * phy_rate_matching_to_str - Return a string describing the rate matching
+ *
+ * @rate_matching: Type of rate matching to describe
+ */
+const char *phy_rate_matching_to_str(int rate_matching)
+{
+	switch (rate_matching) {
+	case RATE_MATCH_NONE:
+		return "none";
+	case RATE_MATCH_PAUSE:
+		return "pause";
+	case RATE_MATCH_CRS:
+		return "crs";
+	case RATE_MATCH_OPEN_LOOP:
+		return "open-loop";
+	}
+	return "Unsupported (update phy-core.c)";
+}
+EXPORT_SYMBOL_GPL(phy_rate_matching_to_str);
+
 /* A mapping of all SUPPORTED settings to speed/duplex.  This table
  * must be grouped by speed and sorted in descending match priority
  * - iow, descending speed. */
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index e223f0d..6f2e4c7 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -106,6 +106,33 @@ void phy_print_status(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_print_status);
 
+/**
+ * phy_get_rate_matching - determine if rate matching is supported
+ * @phydev: The phy device to return rate matching for
+ * @iface: The interface mode to use
+ *
+ * This determines the type of rate matching (if any) that @phy supports
+ * using @iface. @iface may be %PHY_INTERFACE_MODE_NA to determine if any
+ * interface supports rate matching.
+ *
+ * Return: The type of rate matching @phy supports for @iface, or
+ *         %RATE_MATCH_NONE.
+ */
+int phy_get_rate_matching(struct phy_device *phydev,
+			  phy_interface_t iface)
+{
+	int ret = RATE_MATCH_NONE;
+
+	if (phydev->drv->get_rate_matching) {
+		mutex_lock(&phydev->lock);
+		ret = phydev->drv->get_rate_matching(phydev, iface);
+		mutex_unlock(&phydev->lock);
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_get_rate_matching);
+
 /**
  * phy_clear_interrupt - Ack the phy device's interrupt
  * @phydev: the phy_device struct
@@ -380,6 +407,7 @@ void phy_ethtool_ksettings_get(struct phy_device *phydev,
 
 	cmd->base.speed = phydev->speed;
 	cmd->base.duplex = phydev->duplex;
+	cmd->base.rate_matching = phydev->rate_matching;
 	if (phydev->interface == PHY_INTERFACE_MODE_MOCA)
 		cmd->base.port = PORT_BNC;
 	else
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 6b63b98..949e3b8 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -155,6 +155,64 @@ static const char *phylink_an_mode_str(unsigned int mode)
 	return mode < ARRAY_SIZE(modestr) ? modestr[mode] : "unknown";
 }
 
+/**
+ * phylink_interface_max_speed() - get the maximum speed of a phy interface
+ * @interface: phy interface mode defined by &typedef phy_interface_t
+ *
+ * Determine the maximum speed of a phy interface. This is intended to help
+ * determine the correct speed to pass to the MAC when the phy is performing
+ * rate matching.
+ *
+ * Return: The maximum speed of @interface
+ */
+static int phylink_interface_max_speed(phy_interface_t interface)
+{
+	switch (interface) {
+	case PHY_INTERFACE_MODE_RMII:
+	case PHY_INTERFACE_MODE_SMII:
+	case PHY_INTERFACE_MODE_REVMII:
+	case PHY_INTERFACE_MODE_MII:
+		return SPEED_100;
+
+	case PHY_INTERFACE_MODE_TBI:
+	case PHY_INTERFACE_MODE_MOCA:
+	case PHY_INTERFACE_MODE_RTBI:
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_TRGMII:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_QSGMII:
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_GMII:
+		return SPEED_1000;
+
+	case PHY_INTERFACE_MODE_2500BASEX:
+		return SPEED_2500;
+
+	case PHY_INTERFACE_MODE_5GBASER:
+		return SPEED_5000;
+
+	case PHY_INTERFACE_MODE_XGMII:
+	case PHY_INTERFACE_MODE_RXAUI:
+	case PHY_INTERFACE_MODE_XAUI:
+	case PHY_INTERFACE_MODE_10GKR:
+	case PHY_INTERFACE_MODE_USXGMII:
+		return SPEED_10000;
+
+	case PHY_INTERFACE_MODE_INTERNAL:
+	case PHY_INTERFACE_MODE_NA:
+	case PHY_INTERFACE_MODE_MAX:
+		/* No idea! Garbage in, unknown out */
+		return SPEED_UNKNOWN;
+	}
+
+	/* If we get here, someone forgot to add an interface mode above */
+	WARN_ON_ONCE(1);
+	return SPEED_UNKNOWN;
+}
+
 static int phylink_validate_mac_and_pcs(struct phylink *pl,
 					unsigned long *supported,
 					struct phylink_link_state *state)
@@ -402,11 +460,12 @@ static void phylink_mac_config(struct phylink *pl,
 			       const struct phylink_link_state *state)
 {
 	phylink_dbg(pl,
-		    "%s: mode=%s/%s/%s/%s adv=%*pb pause=%02x link=%u an=%u\n",
+		    "%s: mode=%s/%s/%s/%s/%s adv=%*pb pause=%02x link=%u an=%u\n",
 		    __func__, phylink_an_mode_str(pl->cur_link_an_mode),
 		    phy_modes(state->interface),
 		    phy_speed_to_str(state->speed),
 		    phy_duplex_to_str(state->duplex),
+		    phy_rate_matching_to_str(state->rate_matching),
 		    __ETHTOOL_LINK_MODE_MASK_NBITS, state->advertising,
 		    state->pause, state->link, state->an_enabled);
 
@@ -499,6 +558,7 @@ static void phylink_mac_pcs_get_state(struct phylink *pl,
 	linkmode_zero(state->lp_advertising);
 	state->interface = pl->link_config.interface;
 	state->an_enabled = pl->link_config.an_enabled;
+	state->rate_matching = pl->link_config.rate_matching;
 	if (state->an_enabled) {
 		state->speed = SPEED_UNKNOWN;
 		state->duplex = DUPLEX_UNKNOWN;
@@ -614,9 +674,32 @@ static void phylink_link_up(struct phylink *pl,
 {
 	struct net_device *ndev = pl->netdev;
 	int speed, duplex;
+	bool rx_pause;
 
 	speed = link_state.speed;
 	duplex = link_state.duplex;
+	rx_pause = !!(link_state.pause & MLO_PAUSE_RX);
+
+	switch (link_state.rate_matching) {
+	case RATE_MATCH_PAUSE:
+		/* The PHY is doing rate matchion from the media rate (in
+		 * the link_state) to the interface speed, and will send
+		 * pause frames to the MAC to limit its transmission speed.
+		 */
+		speed = phylink_interface_max_speed(link_state.interface);
+		duplex = DUPLEX_FULL;
+		rx_pause = true;
+		break;
+
+	case RATE_MATCH_CRS:
+		/* The PHY is doing rate matchion from the media rate (in
+		 * the link_state) to the interface speed, and will cause
+		 * collisions to the MAC to limit its transmission speed.
+		 */
+		speed = phylink_interface_max_speed(link_state.interface);
+		duplex = DUPLEX_HALF;
+		break;
+	}
 
 	pl->cur_interface = link_state.interface;
 
@@ -626,8 +709,7 @@ static void phylink_link_up(struct phylink *pl,
 
 	pl->mac_ops->mac_link_up(pl->config, pl->phydev, pl->cur_link_an_mode,
 				 pl->cur_interface, speed, duplex,
-				 !!(link_state.pause & MLO_PAUSE_TX),
-				 !!(link_state.pause & MLO_PAUSE_RX));
+				 !!(link_state.pause & MLO_PAUSE_TX), rx_pause);
 
 	if (ndev)
 		netif_carrier_on(ndev);
@@ -719,6 +801,17 @@ static void phylink_resolve(struct work_struct *w)
 				}
 				link_state.interface = pl->phy_state.interface;
 
+				/* If we are doing rate matching, then the
+				 * link speed/duplex comes from the PHY
+				 */
+				if (pl->phy_state.rate_matching) {
+					link_state.rate_matching =
+						pl->phy_state.rate_matching;
+					link_state.speed = pl->phy_state.speed;
+					link_state.duplex =
+						pl->phy_state.duplex;
+				}
+
 				/* If we have a PHY, we need to update with
 				 * the PHY flow control bits.
 				 */
@@ -935,6 +1028,7 @@ static void phylink_phy_change(struct phy_device *phydev, bool up,
 	mutex_lock(&pl->state_mutex);
 	pl->phy_state.speed = phydev->speed;
 	pl->phy_state.duplex = phydev->duplex;
+	pl->phy_state.rate_matching = phydev->rate_matching;
 	pl->phy_state.pause = MLO_PAUSE_NONE;
 	if (phydev->pause)
 		pl->phy_state.pause |= MLO_PAUSE_SYM;
@@ -946,10 +1040,11 @@ static void phylink_phy_change(struct phy_device *phydev, bool up,
 
 	phylink_run_resolve(pl);
 
-	phylink_dbg(pl, "phy link %s %s/%s/%s\n", up ? "up" : "down",
+	phylink_dbg(pl, "phy link %s %s/%s/%s/%s\n", up ? "up" : "down",
 		    phy_modes(phydev->interface),
 		    phy_speed_to_str(phydev->speed),
-		    phy_duplex_to_str(phydev->duplex));
+		    phy_duplex_to_str(phydev->duplex),
+		    phy_rate_matching_to_str(phydev->rate_matching));
 }
 
 static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
@@ -971,6 +1066,12 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
 	memset(&config, 0, sizeof(config));
 	linkmode_copy(supported, phy->supported);
 	linkmode_copy(config.advertising, phy->advertising);
+
+	/* Check whether we would use rate matching for the proposed interface
+	 * mode.
+	 */
+	config.rate_matching = phy_get_rate_matching(phy, interface);
+
 	config.interface = interface;
 
 	ret = phylink_validate(pl, supported, &config);
@@ -988,6 +1089,7 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
 	mutex_lock(&pl->state_mutex);
 	pl->phydev = phy;
 	pl->phy_state.interface = interface;
+	pl->phy_state.rate_matching = RATE_MATCH_NONE;
 	linkmode_copy(pl->supported, supported);
 	linkmode_copy(pl->link_config.advertising, config.advertising);
 
@@ -1348,8 +1450,10 @@ static void phylink_get_ksettings(const struct phylink_link_state *state,
 {
 	phylink_merge_link_mode(kset->link_modes.advertising, state->advertising);
 	linkmode_copy(kset->link_modes.lp_advertising, state->lp_advertising);
-	kset->base.speed = state->speed;
-	kset->base.duplex = state->duplex;
+	if (kset->base.rate_matching == RATE_MATCH_NONE) {
+		kset->base.speed = state->speed;
+		kset->base.duplex = state->duplex;
+	}
 	kset->base.autoneg = state->an_enabled ? AUTONEG_ENABLE :
 				AUTONEG_DISABLE;
 }
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 4f2c105..df9fb90 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -423,6 +423,8 @@ struct phy_device {
 	/* Interrupts are enabled */
 	unsigned interrupts:1;
 
+	int rate_matching;
+
 	enum phy_state state;
 
 	u32 dev_flags;
@@ -544,6 +546,18 @@ struct phy_driver {
 	 */
 	int (*get_features)(struct phy_device *phydev);
 
+	/**
+	 * @get_rate_matching: Get the supported type of rate matching for a
+	 * particular phy interface. This is used by phy consumers to determine
+	 * whether to advertise lower-speed modes for that interface. It is
+	 * assumed that if a rate matching mode is supported on an interface,
+	 * then that interface's rate can be adapted to all slower link speeds
+	 * supported by the phy. If the interface is not supported, this should
+	 * return %RATE_MATCH_NONE.
+	 */
+	int (*get_rate_matching)(struct phy_device *phydev,
+				   phy_interface_t iface);
+
 	/* PHY Power Management */
 	int (*suspend)(struct phy_device *phydev);
 	int (*resume)(struct phy_device *phydev);
@@ -704,6 +718,7 @@ struct phy_fixup {
 
 const char *phy_speed_to_str(int speed);
 const char *phy_duplex_to_str(unsigned int duplex);
+const char *phy_rate_matching_to_str(int rate_matching);
 
 /* A structure for mapping a particular speed and duplex
  * combination to a particular SUPPORTED and ADVERTISED value
@@ -1242,6 +1257,8 @@ int phy_mii_ioctl(struct phy_device *phydev, struct ifreq *ifr, int cmd);
 void phy_request_interrupt(struct phy_device *phydev);
 void phy_free_interrupt(struct phy_device *phydev);
 void phy_print_status(struct phy_device *phydev);
+int phy_get_rate_matching(struct phy_device *phydev,
+			    phy_interface_t iface);
 int phy_set_max_speed(struct phy_device *phydev, u32 max_speed);
 void phy_remove_link_mode(struct phy_device *phydev, u32 link_mode);
 void phy_advertise_supported(struct phy_device *phydev);
diff --git a/include/linux/phylink.h b/include/linux/phylink.h
index 48ff9fe..e1c022f 100644
--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -38,6 +38,10 @@ static inline bool phylink_autoneg_inband(unsigned int mode)
  * @speed: link speed, one of the SPEED_* constants.
  * @duplex: link duplex mode, one of DUPLEX_* constants.
  * @pause: link pause state, described by MLO_PAUSE_* constants.
+ * @rate_matching: rate matching being performed, one of the RATE_MATCH_*
+ *   constants. If rate matching is taking place, then the speed/duplex of
+ *   the medium link mode (@speed and @duplex) and the speed/duplex of the phy
+ *   interface mode (@interface) are different.
  * @link: true if the link is up.
  * @an_enabled: true if autonegotiation is enabled/desired.
  * @an_complete: true if autonegotiation has completed.
@@ -49,6 +53,7 @@ struct phylink_link_state {
 	int speed;
 	int duplex;
 	int pause;
+	int rate_matching;
 	unsigned int link:1;
 	unsigned int an_enabled:1;
 	unsigned int an_complete:1;
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index 8d465e5..ce41d2f 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -1643,6 +1643,20 @@ static inline int ethtool_validate_duplex(__u8 duplex)
 	return 0;
 }
 
+/* These are used to throttle the rate of data on the phy interface when the
+ * native speed of the interface is higher than the link speed. These should
+ * not be used for phy interfaces which natively support multiple speeds (e.g.
+ * MII or SGMII).
+ */
+/* No rate matching performed. */
+#define RATE_MATCH_NONE		0
+/* The phy sends pause frames to throttle the MAC. */
+#define RATE_MATCH_PAUSE	1
+/* The phy asserts CRS to prevent the MAC from transmitting. */
+#define RATE_MATCH_CRS		2
+/* The MAC is programmed with a sufficiently-large IPG. */
+#define RATE_MATCH_OPEN_LOOP	3
+
 /* Which connector port. */
 #define PORT_TP			0x00
 #define PORT_AUI		0x01
@@ -1832,6 +1846,7 @@ enum ethtool_reset_flags {
  *	autonegotiation; 0 if unknown or not applicable.  Read-only.
  * @transceiver: Used to distinguish different possible PHY types,
  *	reported consistently by PHYLIB.  Read-only.
+ * @rate_matching: Rate adaptation performed by the PHY
  *
  * If autonegotiation is disabled, the speed and @duplex represent the
  * fixed link mode and are writable if the driver supports multiple
@@ -1879,7 +1894,8 @@ struct ethtool_link_settings {
 	__u8	eth_tp_mdix_ctrl;
 	__s8	link_mode_masks_nwords;
 	__u8	transceiver;
-	__u8	reserved1[3];
+	__u8	reserved1[2];
+	__u8	rate_matching;
 	__u32	reserved[7];
 	__u32	link_mode_masks[0];
 	/* layout of link_mode_masks fields:
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 9ae38c3..41a8b1d 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -656,6 +656,7 @@ static int ethtool_get_link_ksettings(struct net_device *dev,
 	link_ksettings.base.cmd = ETHTOOL_GLINKSETTINGS;
 	link_ksettings.base.link_mode_masks_nwords
 		= __ETHTOOL_LINK_MODE_MASK_NU32;
+	link_ksettings.base.rate_matching = RATE_MATCH_NONE;
 
 	return store_link_ksettings_for_user(useraddr, &link_ksettings);
 }