diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index 8e4dbfdca237..750e7b7c554e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -96,6 +96,22 @@ static int intel_serdes_powerup(struct net_device *ndev, void *priv_data)
 
 	serdes_phy_addr = intel_priv->mdio_adhoc_addr;
 
+	/* Set the serdes rate and the PCLK rate */
+	data = mdiobus_read(priv->mii, serdes_phy_addr,
+			    SERDES_GCR0);
+
+	data &= ~SERDES_RATE_MASK;
+	data &= ~SERDES_PCLK_MASK;
+
+	if (priv->plat->speed_2500_en)
+		data |= SERDES_RATE_PCIE_GEN2 << SERDES_RATE_PCIE_SHIFT |
+			SERDES_PCLK_37p5MHZ << SERDES_PCLK_SHIFT;
+	else
+		data |= SERDES_RATE_PCIE_GEN1 << SERDES_RATE_PCIE_SHIFT |
+			SERDES_PCLK_70MHZ << SERDES_PCLK_SHIFT;
+
+	mdiobus_write(priv->mii, serdes_phy_addr, SERDES_GCR0, data);
+
 	/* assert clk_req */
 	data = mdiobus_read(priv->mii, serdes_phy_addr, SERDES_GCR0);
 	data |= SERDES_PLL_CLK;
@@ -214,6 +230,28 @@ static void intel_serdes_powerdown(struct net_device *ndev, void *intel_data)
 	}
 }
 
+static bool intel_speed_mode_2500(struct net_device *ndev, void *intel_data)
+{
+	struct intel_priv_data *intel_priv = intel_data;
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	int serdes_phy_addr = 0;
+	u32 data = 0;
+
+	serdes_phy_addr = intel_priv->mdio_adhoc_addr;
+
+	/* Determine the link speed mode: 2.5Gbps/1Gbps */
+	data = mdiobus_read(priv->mii, serdes_phy_addr,
+			    SERDES_GCR);
+
+	if (((data & SERDES_LINK_MODE_MASK) >> SERDES_LINK_MODE_SHIFT) ==
+	    SERDES_LINK_MODE_2G5) {
+		dev_info(priv->device, "Link Speed Mode: 2.5Gbps\n");
+		return true;
+	} else {
+		return false;
+	}
+}
+
 /* Program PTP Clock Frequency for different variant of
  * Intel mGBE that has slightly different GPO mapping
  */
@@ -405,7 +443,7 @@ static int ehl_sgmii_data(struct pci_dev *pdev,
 {
 	plat->bus_id = 1;
 	plat->phy_interface = PHY_INTERFACE_MODE_SGMII;
-
+	plat->speed_mode_2500 = intel_speed_mode_2500;
 	plat->serdes_powerup = intel_serdes_powerup;
 	plat->serdes_powerdown = intel_serdes_powerdown;
 
@@ -456,6 +494,7 @@ static int ehl_pse0_sgmii1g_data(struct pci_dev *pdev,
 				 struct plat_stmmacenet_data *plat)
 {
 	plat->phy_interface = PHY_INTERFACE_MODE_SGMII;
+	plat->speed_mode_2500 = intel_speed_mode_2500;
 	plat->serdes_powerup = intel_serdes_powerup;
 	plat->serdes_powerdown = intel_serdes_powerdown;
 	return ehl_pse0_common_data(pdev, plat);
@@ -492,6 +531,7 @@ static int ehl_pse1_sgmii1g_data(struct pci_dev *pdev,
 				 struct plat_stmmacenet_data *plat)
 {
 	plat->phy_interface = PHY_INTERFACE_MODE_SGMII;
+	plat->speed_mode_2500 = intel_speed_mode_2500;
 	plat->serdes_powerup = intel_serdes_powerup;
 	plat->serdes_powerdown = intel_serdes_powerdown;
 	return ehl_pse1_common_data(pdev, plat);
@@ -516,6 +556,7 @@ static int tgl_sgmii_phy0_data(struct pci_dev *pdev,
 {
 	plat->bus_id = 1;
 	plat->phy_interface = PHY_INTERFACE_MODE_SGMII;
+	plat->speed_mode_2500 = intel_speed_mode_2500;
 	plat->serdes_powerup = intel_serdes_powerup;
 	plat->serdes_powerdown = intel_serdes_powerdown;
 	return tgl_common_data(pdev, plat);
@@ -530,6 +571,7 @@ static int tgl_sgmii_phy1_data(struct pci_dev *pdev,
 {
 	plat->bus_id = 2;
 	plat->phy_interface = PHY_INTERFACE_MODE_SGMII;
+	plat->speed_mode_2500 = intel_speed_mode_2500;
 	plat->serdes_powerup = intel_serdes_powerup;
 	plat->serdes_powerdown = intel_serdes_powerdown;
 	return tgl_common_data(pdev, plat);
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.h b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.h
index e723096c0b15..021a5c178d97 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.h
@@ -9,6 +9,7 @@
 #define POLL_DELAY_US 8
 
 /* SERDES Register */
+#define SERDES_GCR	0x0	/* Global Conguration */
 #define SERDES_GSR0	0x5	/* Global Status Reg0 */
 #define SERDES_GCR0	0xb	/* Global Configuration Reg0 */
 
@@ -16,8 +17,20 @@
 #define SERDES_PLL_CLK		BIT(0)		/* PLL clk valid signal */
 #define SERDES_RST		BIT(2)		/* Serdes Reset */
 #define SERDES_PWR_ST_MASK	GENMASK(6, 4)	/* Serdes Power state*/
+#define SERDES_RATE_MASK	GENMASK(9, 8)
+#define SERDES_PCLK_MASK	GENMASK(14, 12)	/* PCLK rate to PHY */
+#define SERDES_LINK_MODE_MASK	GENMASK(2, 1)
+#define SERDES_LINK_MODE_SHIFT	1
 #define SERDES_PWR_ST_SHIFT	4
 #define SERDES_PWR_ST_P0	0x0
 #define SERDES_PWR_ST_P3	0x3
+#define SERDES_LINK_MODE_2G5	0x3
+#define SERSED_LINK_MODE_1G	0x2
+#define SERDES_PCLK_37p5MHZ	0x0
+#define SERDES_PCLK_70MHZ	0x1
+#define SERDES_RATE_PCIE_GEN1	0x0
+#define SERDES_RATE_PCIE_GEN2	0x1
+#define SERDES_RATE_PCIE_SHIFT	8
+#define SERDES_PCLK_SHIFT	12
 
 #endif /* __DWMAC_INTEL_H__ */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
index 29f765a246a0..cbfc4de7e9a3 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
@@ -1349,6 +1349,7 @@ int dwmac4_setup(struct stmmac_priv *priv)
 	mac->link.speed10 = GMAC_CONFIG_PS;
 	mac->link.speed100 = GMAC_CONFIG_FES | GMAC_CONFIG_PS;
 	mac->link.speed1000 = 0;
+	mac->link.speed2500 = GMAC_CONFIG_FES;
 	mac->link.speed_mask = GMAC_CONFIG_FES | GMAC_CONFIG_PS;
 	mac->mii.addr = GMAC_MDIO_ADDR;
 	mac->mii.data = GMAC_MDIO_DATA;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c89f0421bfdb..df582ad7892a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -877,6 +877,25 @@ static void stmmac_validate(struct phylink_config *config,
 	phylink_set(mac_supported, Asym_Pause);
 	phylink_set_port_modes(mac_supported);
 
+	if (priv->plat->has_gmac ||
+	    priv->plat->has_gmac4 ||
+	    priv->plat->has_xgmac) {
+		phylink_set(mac_supported, 1000baseT_Half);
+		phylink_set(mac_supported, 1000baseT_Full);
+		phylink_set(mac_supported, 1000baseKX_Full);
+	}
+
+	/* 2.5G mode only support 2500baseT full duplex only */
+	if (priv->plat->has_gmac4 && priv->plat->speed_2500_en) {
+		phylink_set(mac_supported, 2500baseT_Full);
+		phylink_set(mask, 10baseT_Half);
+		phylink_set(mask, 10baseT_Full);
+		phylink_set(mask, 100baseT_Half);
+		phylink_set(mask, 100baseT_Full);
+		phylink_set(mask, 1000baseT_Half);
+		phylink_set(mask, 1000baseT_Full);
+	}
+
 	/* Cut down 1G if asked to */
 	if ((max_speed > 0) && (max_speed < 1000)) {
 		phylink_set(mask, 1000baseT_Full);
@@ -1166,8 +1185,14 @@ static int stmmac_phy_setup(struct stmmac_priv *priv)
 	priv->phylink_config.dev = &priv->dev->dev;
 	priv->phylink_config.type = PHYLINK_NETDEV;
 	priv->phylink_config.pcs_poll = true;
-	priv->phylink_config.ovr_an_inband =
-		priv->plat->mdio_bus_data->xpcs_an_inband;
+	/* For 2.5G, we do not use SGMII in-band AN */
+	if (priv->plat->speed_2500_en) {
+		priv->phylink_config.ovr_an_inband = false;
+	} else {
+		priv->phylink_config.ovr_an_inband =
+			priv->plat->mdio_bus_data->xpcs_an_inband;
+	}
+
 
 	if (!fwnode)
 		fwnode = dev_fwnode(priv->device);
@@ -5284,6 +5309,12 @@ int stmmac_dvr_probe(struct device *device,
 		}
 	}
 
+	if (priv->plat->speed_mode_2500) {
+		priv->plat->speed_2500_en = priv->plat->speed_mode_2500(ndev,
+									priv->plat->bsp_priv);
+		priv->hw->xpcs_args.speed_2500_en = priv->plat->speed_2500_en;
+	}
+
 	ret = stmmac_phy_setup(priv);
 	if (ret) {
 		netdev_err(ndev, "failed to setup phy (%d)\n", ret);
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index bf73982f92b3..d68805a57eb4 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -182,6 +182,7 @@ struct plat_stmmacenet_data {
 	void (*fix_mac_speed)(void *priv, unsigned int speed);
 	int (*serdes_powerup)(struct net_device *ndev, void *priv);
 	void (*serdes_powerdown)(struct net_device *ndev, void *priv);
+	bool (*speed_mode_2500)(struct net_device *ndev, void *priv);
 	void (*ptp_clk_freq_config)(void *priv);
 	int (*init)(struct platform_device *pdev, void *priv);
 	void (*exit)(struct platform_device *pdev, void *priv);
@@ -205,6 +206,7 @@ struct plat_stmmacenet_data {
 	int has_xgmac;
 	bool vlan_fail_q_en;
 	u8 vlan_fail_q;
+	bool speed_2500_en;
 	unsigned int eee_usecs_rate;
 	struct pci_dev *pdev;
 	bool has_safety_feat;
