net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode

Update the axienet driver to properly support the Xilinx PCS/PMA PHY
component which is used for 1000BaseX and SGMII modes, including
properly configuring the auto-negotiation mode of the PHY and reading
the negotiated state from the PHY.
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>
Link: https://lore.kernel.org/r/20201028171429.1699922-1-robert.hancock@calian.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/xilinx/xilinx_axienet.h

@@ -419,6 +419,9 @@ struct axienet_local {
 	struct phylink *phylink;
 	struct phylink_config phylink_config;
 
+	/* Reference to PCS/PMA PHY if used */
+	struct mdio_device *pcs_phy;
+
 	/* Clock for AXI bus */
 	struct clk *clk;
 

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1517,10 +1517,27 @@ static void axienet_validate(struct phylink_config *config,
 
 	phylink_set(mask, Asym_Pause);
 	phylink_set(mask, Pause);
-	phylink_set(mask, 1000baseX_Full);
-	phylink_set(mask, 10baseT_Full);
-	phylink_set(mask, 100baseT_Full);
-	phylink_set(mask, 1000baseT_Full);
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_NA:
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_GMII:
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		phylink_set(mask, 1000baseX_Full);
+		phylink_set(mask, 1000baseT_Full);
+		if (state->interface == PHY_INTERFACE_MODE_1000BASEX)
+			break;
+		fallthrough;
+	case PHY_INTERFACE_MODE_MII:
+		phylink_set(mask, 100baseT_Full);
+		phylink_set(mask, 10baseT_Full);
+	default:
+		break;
+	}
 
 	bitmap_and(supported, supported, mask,
 		   __ETHTOOL_LINK_MODE_MASK_NBITS);
@@ -1533,38 +1550,46 @@ static void axienet_mac_pcs_get_state(struct phylink_config *config,
 {
 	struct net_device *ndev = to_net_dev(config->dev);
 	struct axienet_local *lp = netdev_priv(ndev);
-	u32 emmc_reg, fcc_reg;
-
-	state->interface = lp->phy_mode;
-
-	emmc_reg = axienet_ior(lp, XAE_EMMC_OFFSET);
-	if (emmc_reg & XAE_EMMC_LINKSPD_1000)
-		state->speed = SPEED_1000;
-	else if (emmc_reg & XAE_EMMC_LINKSPD_100)
-		state->speed = SPEED_100;
-	else
-		state->speed = SPEED_10;
-
-	state->pause = 0;
-	fcc_reg = axienet_ior(lp, XAE_FCC_OFFSET);
-	if (fcc_reg & XAE_FCC_FCTX_MASK)
-		state->pause |= MLO_PAUSE_TX;
-	if (fcc_reg & XAE_FCC_FCRX_MASK)
-		state->pause |= MLO_PAUSE_RX;
 
-	state->an_complete = 0;
-	state->duplex = 1;
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		phylink_mii_c22_pcs_get_state(lp->pcs_phy, state);
+		break;
+	default:
+		break;
+	}
 }
 
 static void axienet_mac_an_restart(struct phylink_config *config)
 {
-	/* Unsupported, do nothing */
+	struct net_device *ndev = to_net_dev(config->dev);
+	struct axienet_local *lp = netdev_priv(ndev);
+
+	phylink_mii_c22_pcs_an_restart(lp->pcs_phy);
 }
 
 static void axienet_mac_config(struct phylink_config *config, unsigned int mode,
 			       const struct phylink_link_state *state)
 {
-	/* nothing meaningful to do */
+	struct net_device *ndev = to_net_dev(config->dev);
+	struct axienet_local *lp = netdev_priv(ndev);
+	int ret;
+
+	switch (state->interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_1000BASEX:
+		ret = phylink_mii_c22_pcs_config(lp->pcs_phy, mode,
+						 state->interface,
+						 state->advertising);
+		if (ret < 0)
+			netdev_warn(ndev, "Failed to configure PCS: %d\n",
+				    ret);
+		break;
+
+	default:
+		break;
+	}
 }
 
 static void axienet_mac_link_down(struct phylink_config *config,
@@ -1999,6 +2024,20 @@ static int axienet_probe(struct platform_device *pdev)
 			dev_warn(&pdev->dev,
 				 "error registering MDIO bus: %d\n", ret);
 	}
+	if (lp->phy_mode == PHY_INTERFACE_MODE_SGMII ||
+	    lp->phy_mode == PHY_INTERFACE_MODE_1000BASEX) {
+		if (!lp->phy_node) {
+			dev_err(&pdev->dev, "phy-handle required for 1000BaseX/SGMII\n");
+			ret = -EINVAL;
+			goto free_netdev;
+		}
+		lp->pcs_phy = of_mdio_find_device(lp->phy_node);
+		if (!lp->pcs_phy) {
+			ret = -EPROBE_DEFER;
+			goto free_netdev;
+		}
+		lp->phylink_config.pcs_poll = true;
+	}
 
 	lp->phylink_config.dev = &ndev->dev;
 	lp->phylink_config.type = PHYLINK_NETDEV;
@@ -2036,6 +2075,9 @@ static int axienet_remove(struct platform_device *pdev)
 	if (lp->phylink)
 		phylink_destroy(lp->phylink);
 
+	if (lp->pcs_phy)
+		put_device(&lp->pcs_phy->dev);
+
 	axienet_mdio_teardown(lp);
 
 	clk_disable_unprepare(lp->clk);