net: stmmac: dwmac-qcom-ethqos: Add support for 2.5G SGMII

Serdes phy needs to operate at 2500 mode for 2.5G speed and 1000
mode for 1G/100M/10M speed.
Added changes to configure serdes phy and mac based on link speed.
Changing serdes phy speed involves multiple register writes for
serdes block. To avoid redundant write operations only update serdes
phy when new speed is different.
For 2500 speed MAC PCS autoneg needs to disabled. Added changes to
disable MAC PCS autoneg if ANE parameter is not set.

Signed-off-by: Sneh Shah <quic_snehshah@quicinc.com>
Tested-by: Abhishek Chauhan <quic_abchauha@quicinc.com> # sa8775p-ride
Reviewed-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-qcom-ethqos.c

@@ -106,6 +106,7 @@ struct qcom_ethqos {
 	struct clk *link_clk;
 	struct phy *serdes_phy;
 	unsigned int speed;
+	int serdes_speed;
 	phy_interface_t phy_mode;
 
 	const struct ethqos_emac_por *por;
@@ -606,19 +607,39 @@ static int ethqos_configure_rgmii(struct qcom_ethqos *ethqos)
  */
 static int ethqos_configure_sgmii(struct qcom_ethqos *ethqos)
 {
+	struct net_device *dev = platform_get_drvdata(ethqos->pdev);
+	struct stmmac_priv *priv = netdev_priv(dev);
 	int val;
 
 	val = readl(ethqos->mac_base + MAC_CTRL_REG);
 
 	switch (ethqos->speed) {
+	case SPEED_2500:
+		val &= ~ETHQOS_MAC_CTRL_PORT_SEL;
+		rgmii_updatel(ethqos, RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
+			      RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
+			      RGMII_IO_MACRO_CONFIG2);
+		if (ethqos->serdes_speed != SPEED_2500)
+			phy_set_speed(ethqos->serdes_phy, SPEED_2500);
+		ethqos->serdes_speed = SPEED_2500;
+		stmmac_pcs_ctrl_ane(priv, priv->ioaddr, 0, 0, 0);
+		break;
 	case SPEED_1000:
 		val &= ~ETHQOS_MAC_CTRL_PORT_SEL;
 		rgmii_updatel(ethqos, RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
 			      RGMII_CONFIG2_RGMII_CLK_SEL_CFG,
 			      RGMII_IO_MACRO_CONFIG2);
+		if (ethqos->serdes_speed != SPEED_1000)
+			phy_set_speed(ethqos->serdes_phy, SPEED_1000);
+		ethqos->serdes_speed = SPEED_1000;
+		stmmac_pcs_ctrl_ane(priv, priv->ioaddr, 1, 0, 0);
 		break;
 	case SPEED_100:
 		val |= ETHQOS_MAC_CTRL_PORT_SEL | ETHQOS_MAC_CTRL_SPEED_MODE;
+		if (ethqos->serdes_speed != SPEED_1000)
+			phy_set_speed(ethqos->serdes_phy, SPEED_1000);
+		ethqos->serdes_speed = SPEED_1000;
+		stmmac_pcs_ctrl_ane(priv, priv->ioaddr, 1, 0, 0);
 		break;
 	case SPEED_10:
 		val |= ETHQOS_MAC_CTRL_PORT_SEL;
@@ -627,6 +648,10 @@ static int ethqos_configure_sgmii(struct qcom_ethqos *ethqos)
 			      FIELD_PREP(RGMII_CONFIG_SGMII_CLK_DVDR,
 					 SGMII_10M_RX_CLK_DVDR),
 			      RGMII_IO_MACRO_CONFIG);
+		if (ethqos->serdes_speed != SPEED_1000)
+			phy_set_speed(ethqos->serdes_phy, ethqos->speed);
+		ethqos->serdes_speed = SPEED_1000;
+		stmmac_pcs_ctrl_ane(priv, priv->ioaddr, 1, 0, 0);
 		break;
 	}
 
@@ -799,6 +824,7 @@ static int qcom_ethqos_probe(struct platform_device *pdev)
 				     "Failed to get serdes phy\n");
 
 	ethqos->speed = SPEED_1000;
+	ethqos->serdes_speed = SPEED_1000;
 	ethqos_update_link_clk(ethqos, SPEED_1000);
 	ethqos_set_func_clk_en(ethqos);
 

drivers/net/ethernet/stmicro/stmmac/stmmac_pcs.h

@@ -110,6 +110,8 @@ static inline void dwmac_ctrl_ane(void __iomem *ioaddr, u32 reg, bool ane,
 	/* Enable and restart the Auto-Negotiation */
 	if (ane)
 		value |= GMAC_AN_CTRL_ANE | GMAC_AN_CTRL_RAN;
+	else
+		value &= ~GMAC_AN_CTRL_ANE;
 
 	/* In case of MAC-2-MAC connection, block is configured to operate
 	 * according to MAC conf register.