amd-xgbe-phy: Enhance parallel detection to support KR speed

Add support to allow parallel detection to work in KR speed. With
both speed modes of KX and KR supported, KX must be checked first.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/amd-xgbe-phy.c

@@ -100,9 +100,11 @@ MODULE_DESCRIPTION("AMD 10GbE (amd-xgbe) PHY driver");
 #ifndef MDIO_PMA_10GBR_PMD_CTRL
 #define MDIO_PMA_10GBR_PMD_CTRL		0x0096
 #endif
+
 #ifndef MDIO_PMA_10GBR_FEC_CTRL
 #define MDIO_PMA_10GBR_FEC_CTRL		0x00ab
 #endif
+
 #ifndef MDIO_AN_XNP
 #define MDIO_AN_XNP			0x0016
 #endif
@@ -110,14 +112,23 @@ MODULE_DESCRIPTION("AMD 10GbE (amd-xgbe) PHY driver");
 #ifndef MDIO_AN_INTMASK
 #define MDIO_AN_INTMASK			0x8001
 #endif
+
 #ifndef MDIO_AN_INT
 #define MDIO_AN_INT			0x8002
 #endif
 
+#ifndef MDIO_AN_KR_CTRL
+#define MDIO_AN_KR_CTRL			0x8003
+#endif
+
 #ifndef MDIO_CTRL1_SPEED1G
 #define MDIO_CTRL1_SPEED1G		(MDIO_CTRL1_SPEED10G & ~BMCR_SPEED100)
 #endif
 
+#ifndef MDIO_KR_CTRL_PDETECT
+#define MDIO_KR_CTRL_PDETECT		0x01
+#endif
+
 /* SerDes integration register offsets */
 #define SIR0_KR_RT_1			0x002c
 #define SIR0_STATUS			0x0040
@@ -341,6 +352,7 @@ struct amd_xgbe_phy_priv {
 	enum amd_xgbe_phy_rx kx_state;
 	struct work_struct an_work;
 	struct workqueue_struct *an_workqueue;
+	unsigned int parallel_detect;
 };
 
 static int amd_xgbe_an_enable_kr_training(struct phy_device *phydev)
@@ -808,6 +820,13 @@ static enum amd_xgbe_phy_an amd_xgbe_an_start(struct phy_device *phydev)
 	/* Enable and start auto-negotiation */
 	phy_write_mmd(phydev, MDIO_MMD_AN, MDIO_AN_INT, 0);
 
+	ret = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_AN_KR_CTRL);
+	if (ret < 0)
+		return AMD_XGBE_AN_ERROR;
+
+	ret |= MDIO_KR_CTRL_PDETECT;
+	phy_write_mmd(phydev, MDIO_MMD_AN, MDIO_AN_KR_CTRL, ret);
+
 	ret = phy_read_mmd(phydev, MDIO_MMD_AN, MDIO_CTRL1);
 	if (ret < 0)
 		return AMD_XGBE_AN_ERROR;
@@ -888,6 +907,10 @@ static void amd_xgbe_an_state_machine(struct work_struct *work)
 	int sleep;
 	unsigned int an_supported = 0;
 
+	/* Start in KX mode */
+	if (amd_xgbe_phy_set_mode(phydev, AMD_XGBE_MODE_KX))
+		priv->an_state = AMD_XGBE_AN_ERROR;
+
 	while (1) {
 		mutex_lock(&priv->an_mutex);
 
@@ -895,8 +918,9 @@ static void amd_xgbe_an_state_machine(struct work_struct *work)
 
 		switch (priv->an_state) {
 		case AMD_XGBE_AN_START:
-			priv->an_state = amd_xgbe_an_start(phydev);
 			an_supported = 0;
+			priv->parallel_detect = 0;
+			priv->an_state = amd_xgbe_an_start(phydev);
 			break;
 
 		case AMD_XGBE_AN_EVENT:
@@ -913,6 +937,7 @@ static void amd_xgbe_an_state_machine(struct work_struct *work)
 			break;
 
 		case AMD_XGBE_AN_COMPLETE:
+			priv->parallel_detect = an_supported ? 0 : 1;
 			netdev_info(phydev->attached_dev, "%s successful\n",
 				    an_supported ? "Auto negotiation"
 						 : "Parallel detection");
@@ -1150,7 +1175,8 @@ static int amd_xgbe_phy_read_status(struct phy_device *phydev)
 	if (ret)
 		return ret;
 
-	if (phydev->autoneg == AUTONEG_ENABLE) {
+	if ((phydev->autoneg == AUTONEG_ENABLE) &&
+	    !priv->parallel_detect) {
 		if (!(mmd_mask & MDIO_DEVS_AN))
 			return -EINVAL;