ixgbe: Fix 82599 adapter link flickering issues

Fix autoneg restart issues in flow control path which might create
endless link flickering due to known timing issues with 82599
adapters.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakakla@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 31 insertions, 84 deletions

diff --git a/drivers/net/ixgbe/ixgbe_82598.c b/drivers/net/ixgbe/ixgbe_82598.c
index 88e8350aa786..b9923047ce11 100644
--- a/drivers/net/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ixgbe/ixgbe_82598.c
@@ -293,6 +293,17 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
 	u32 rmcs_reg;
 	u32 reg;
 
+#ifdef CONFIG_DCB
+	if (hw->fc.requested_mode == ixgbe_fc_pfc)
+		goto out;
+
+#endif /* CONFIG_DCB */
+	/* Negotiate the fc mode to use */
+	ret_val = ixgbe_fc_autoneg(hw);
+	if (ret_val)
+		goto out;
+
+	/* Disable any previous flow control settings */
 	fctrl_reg = IXGBE_READ_REG(hw, IXGBE_FCTRL);
 	fctrl_reg &= ~(IXGBE_FCTRL_RFCE | IXGBE_FCTRL_RPFCE);
 
@@ -304,14 +315,20 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
 	 * 0: Flow control is completely disabled
 	 * 1: Rx flow control is enabled (we can receive pause frames,
 	 *    but not send pause frames).
-	 * 2:  Tx flow control is enabled (we can send pause frames but
+	 * 2: Tx flow control is enabled (we can send pause frames but
 	 *     we do not support receiving pause frames).
 	 * 3: Both Rx and Tx flow control (symmetric) are enabled.
 	 * other: Invalid.
+#ifdef CONFIG_DCB
+	 * 4: Priority Flow Control is enabled.
+#endif
 	 */
 	switch (hw->fc.current_mode) {
 	case ixgbe_fc_none:
-		/* Flow control completely disabled by software override. */
+		/*
+		 * Flow control is disabled by software override or autoneg.
+		 * The code below will actually disable it in the HW.
+		 */
 		break;
 	case ixgbe_fc_rx_pause:
 		/*
@@ -336,6 +353,11 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
 		fctrl_reg |= IXGBE_FCTRL_RFCE;
 		rmcs_reg |= IXGBE_RMCS_TFCE_802_3X;
 		break;
+#ifdef CONFIG_DCB
+	case ixgbe_fc_pfc:
+		goto out;
+		break;
+#endif /* CONFIG_DCB */
 	default:
 		hw_dbg(hw, "Flow control param set incorrectly\n");
 		ret_val = -IXGBE_ERR_CONFIG;
@@ -343,7 +365,7 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
 		break;
 	}
 
-	/* Enable 802.3x based flow control settings. */
+	/* Set 802.3x based flow control settings. */
 	fctrl_reg |= IXGBE_FCTRL_DPF;
 	IXGBE_WRITE_REG(hw, IXGBE_FCTRL, fctrl_reg);
 	IXGBE_WRITE_REG(hw, IXGBE_RMCS, rmcs_reg);
@@ -377,79 +399,6 @@ out:
 }
 
 /**
- *  ixgbe_setup_fc_82598 - Configure flow control settings
- *  @hw: pointer to hardware structure
- *  @packetbuf_num: packet buffer number (0-7)
- *
- *  Configures the flow control settings based on SW configuration.  This
- *  function is used for 802.3x flow control configuration only.
- **/
-static s32 ixgbe_setup_fc_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
-{
-	s32 ret_val = 0;
-	ixgbe_link_speed speed;
-	bool link_up;
-
-	/* Validate the packetbuf configuration */
-	if (packetbuf_num < 0 || packetbuf_num > 7) {
-		hw_dbg(hw, "Invalid packet buffer number [%d], expected range is"
-		          " 0-7\n", packetbuf_num);
-		ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
-		goto out;
-	}
-
-	/*
-	 * Validate the water mark configuration.  Zero water marks are invalid
-	 * because it causes the controller to just blast out fc packets.
-	 */
-	if (!hw->fc.low_water || !hw->fc.high_water || !hw->fc.pause_time) {
-		if (hw->fc.requested_mode != ixgbe_fc_none) {
-			hw_dbg(hw, "Invalid water mark configuration\n");
-			ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
-			goto out;
-		}
-	}
-
-	/*
-	 * Validate the requested mode.  Strict IEEE mode does not allow
-	 * ixgbe_fc_rx_pause because it will cause testing anomalies.
-	 */
-	if (hw->fc.strict_ieee && hw->fc.requested_mode == ixgbe_fc_rx_pause) {
-		hw_dbg(hw, "ixgbe_fc_rx_pause not valid in strict IEEE mode\n");
-		ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
-		goto out;
-	}
-
-	/*
-	 * 10gig parts do not have a word in the EEPROM to determine the
-	 * default flow control setting, so we explicitly set it to full.
-	 */
-	if (hw->fc.requested_mode == ixgbe_fc_default)
-		hw->fc.requested_mode = ixgbe_fc_full;
-
-	/*
-	 * Save off the requested flow control mode for use later.  Depending
-	 * on the link partner's capabilities, we may or may not use this mode.
-	 */
-
-	hw->fc.current_mode = hw->fc.requested_mode;
-
-	/* Decide whether to use autoneg or not. */
-	hw->mac.ops.check_link(hw, &speed, &link_up, false);
-	if (!hw->fc.disable_fc_autoneg && hw->phy.multispeed_fiber &&
-	    (speed == IXGBE_LINK_SPEED_1GB_FULL))
-		ret_val = ixgbe_fc_autoneg(hw);
-
-	if (ret_val)
-		goto out;
-
-	ret_val = ixgbe_fc_enable_82598(hw, packetbuf_num);
-
-out:
-	return ret_val;
-}
-
-/**
  *  ixgbe_setup_mac_link_82598 - Configures MAC link settings
  *  @hw: pointer to hardware structure
  *
@@ -488,13 +437,6 @@ static s32 ixgbe_setup_mac_link_82598(struct ixgbe_hw *hw)
 		}
 	}
 
-	/*
-	 * We want to save off the original Flow Control configuration just in
-	 * case we get disconnected and then reconnected into a different hub
-	 * or switch with different Flow Control capabilities.
-	 */
-	ixgbe_setup_fc_82598(hw, 0);
-
 	/* Add delay to filter out noises during initial link setup */
 	msleep(50);
 
@@ -581,6 +523,11 @@ static s32 ixgbe_check_mac_link_82598(struct ixgbe_hw *hw,
 	else
 		*speed = IXGBE_LINK_SPEED_1GB_FULL;
 
+	/* if link is down, zero out the current_mode */
+	if (*link_up == false) {
+		hw->fc.current_mode = ixgbe_fc_none;
+		hw->fc.fc_was_autonegged = false;
+	}
 out:
 	return 0;
 }
@@ -1168,7 +1115,7 @@ static struct ixgbe_mac_operations mac_ops_82598 = {
 	.disable_mc		= &ixgbe_disable_mc_generic,
 	.clear_vfta		= &ixgbe_clear_vfta_82598,
 	.set_vfta		= &ixgbe_set_vfta_82598,
-	.setup_fc		= &ixgbe_setup_fc_82598,
+	.fc_enable		= &ixgbe_fc_enable_82598,
 };
 
 static struct ixgbe_eeprom_operations eeprom_ops_82598 = {