igb: update to allow reading/setting MDI state

This is the implementation for igb to allow forcing MDI state
via ethtool, allowing users to work around some improperly
behaving switches.

Forcing in this driver is for now only allowed when auto-neg is
enabled.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Carolyn Wyborny <carolyn.wyborny@intel.com>
Tested-by: Aaron Brown aaron.f.brown@intel.com
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb_ethtool.c

diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
index a19c84c..cf0e9fb 100644
--- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
+++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
@@ -198,6 +198,19 @@
 	}
 
 	ecmd->autoneg = hw->mac.autoneg ? AUTONEG_ENABLE : AUTONEG_DISABLE;
+
+	/* MDI-X => 2; MDI =>1; Invalid =>0 */
+	if (hw->phy.media_type == e1000_media_type_copper)
+		ecmd->eth_tp_mdix = hw->phy.is_mdix ? ETH_TP_MDI_X :
+						      ETH_TP_MDI;
+	else
+		ecmd->eth_tp_mdix = ETH_TP_MDI_INVALID;
+
+	if (hw->phy.mdix == AUTO_ALL_MODES)
+		ecmd->eth_tp_mdix_ctrl = ETH_TP_MDI_AUTO;
+	else
+		ecmd->eth_tp_mdix_ctrl = hw->phy.mdix;
+
 	return 0;
 }
 
@@ -214,6 +227,22 @@
 		return -EINVAL;
 	}
 
+	/*
+	 * MDI setting is only allowed when autoneg enabled because
+	 * some hardware doesn't allow MDI setting when speed or
+	 * duplex is forced.
+	 */
+	if (ecmd->eth_tp_mdix_ctrl) {
+		if (hw->phy.media_type != e1000_media_type_copper)
+			return -EOPNOTSUPP;
+
+		if ((ecmd->eth_tp_mdix_ctrl != ETH_TP_MDI_AUTO) &&
+		    (ecmd->autoneg != AUTONEG_ENABLE)) {
+			dev_err(&adapter->pdev->dev, "forcing MDI/MDI-X state is not supported when link speed and/or duplex are forced\n");
+			return -EINVAL;
+		}
+	}
+
 	while (test_and_set_bit(__IGB_RESETTING, &adapter->state))
 		msleep(1);
 
@@ -227,12 +256,25 @@
 			hw->fc.requested_mode = e1000_fc_default;
 	} else {
 		u32 speed = ethtool_cmd_speed(ecmd);
+		/* calling this overrides forced MDI setting */
 		if (igb_set_spd_dplx(adapter, speed, ecmd->duplex)) {
 			clear_bit(__IGB_RESETTING, &adapter->state);
 			return -EINVAL;
 		}
 	}
 
+	/* MDI-X => 2; MDI => 1; Auto => 3 */
+	if (ecmd->eth_tp_mdix_ctrl) {
+		/*
+		 * fix up the value for auto (3 => 0) as zero is mapped
+		 * internally to auto
+		 */
+		if (ecmd->eth_tp_mdix_ctrl == ETH_TP_MDI_AUTO)
+			hw->phy.mdix = AUTO_ALL_MODES;
+		else
+			hw->phy.mdix = ecmd->eth_tp_mdix_ctrl;
+	}
+
 	/* reset the link */
 	if (netif_running(adapter->netdev)) {
 		igb_down(adapter);

drivers/net/ethernet/intel/igb/igb_main.c

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index b7c2d50..d4f47a0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6676,6 +6676,10 @@
 	default:
 		goto err_inval;
 	}
+
+	/* clear MDI, MDI(-X) override is only allowed when autoneg enabled */
+	adapter->hw.phy.mdix = AUTO_ALL_MODES;
+
 	return 0;
 
 err_inval: