amd-xgbe-phy: Provide support for auto-negotiation timeout

Currently, there is no interrupt code that indicates auto-negotiation
has timed out. If the auto-negotiation has timed out then the start of
a new auto-negotiation will begin again with a new base page being
received. The state machine could be in a state that is not expecting
this interrupt code which results in an error during auto-negotiation.

Update the code to timestamp when the auto-negotiation starts.  Should
another page received interrupt code occur before auto-negotiation has
completed but after the auto-negotiation timeout, then reset the state
machine to allow the auto-negotiation to continue.
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

@@ -78,6 +78,7 @@
 #include <linux/bitops.h>
 #include <linux/property.h>
 #include <linux/acpi.h>
+#include <linux/jiffies.h>
 
 MODULE_AUTHOR("Tom Lendacky <thomas.lendacky@amd.com>");
 MODULE_LICENSE("Dual BSD/GPL");
@@ -100,6 +101,8 @@ MODULE_DESCRIPTION("AMD 10GbE (amd-xgbe) PHY driver");
 #define XGBE_PHY_SPEED_2500		1
 #define XGBE_PHY_SPEED_10000		2
 
+#define XGBE_AN_MS_TIMEOUT		500
+
 #define XGBE_AN_INT_CMPLT		0x01
 #define XGBE_AN_INC_LINK		0x02
 #define XGBE_AN_PG_RCV			0x04
@@ -434,6 +437,7 @@ struct amd_xgbe_phy_priv {
 	unsigned int an_supported;
 	unsigned int parallel_detect;
 	unsigned int fec_ability;
+	unsigned long an_start;
 
 	unsigned int lpm_ctrl;		/* CTRL1 for resume */
 };
@@ -902,8 +906,23 @@ static enum amd_xgbe_phy_an amd_xgbe_an_page_received(struct phy_device *phydev)
 {
 	struct amd_xgbe_phy_priv *priv = phydev->priv;
 	enum amd_xgbe_phy_rx *state;
+	unsigned long an_timeout;
 	int ret;
 
+	if (!priv->an_start) {
+		priv->an_start = jiffies;
+	} else {
+		an_timeout = priv->an_start +
+			     msecs_to_jiffies(XGBE_AN_MS_TIMEOUT);
+		if (time_after(jiffies, an_timeout)) {
+			/* Auto-negotiation timed out, reset state */
+			priv->kr_state = AMD_XGBE_RX_BPA;
+			priv->kx_state = AMD_XGBE_RX_BPA;
+
+			priv->an_start = jiffies;
+		}
+	}
+
 	state = amd_xgbe_phy_in_kr_mode(phydev) ? &priv->kr_state
 						: &priv->kx_state;
 
@@ -1078,6 +1097,7 @@ static void amd_xgbe_an_state_machine(struct work_struct *work)
 		priv->an_state = AMD_XGBE_AN_READY;
 		priv->kr_state = AMD_XGBE_RX_BPA;
 		priv->kx_state = AMD_XGBE_RX_BPA;
+		priv->an_start = 0;
 	}
 
 	if (cur_state != priv->an_state)