[net-next 4/6] e1000: configure and read MDI settings

[Jeff Kirsher <jeffrey.t.kirsher@intel.com>]

From: Jesse Brandeburg <jesse.brandeburg@intel.com>

This is the implementation in e1000 to allow ethtool to force
MDI state, allowing users to work around some improperly
behaving switches.

Current get_settings behavior slightly changes in that now when link is down
get_settings will return the MDI state of the last link because get_settings
needs to succeed to allow the set to work even when link is down.

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

To use must have the matching version of ethtool app that supports
this functionality.

Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
CC: Tushar Dave <tushar.n.dave@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/e1000/e1000_ethtool.c |   34 ++++++++++++++++++++++
 drivers/net/ethernet/intel/e1000/e1000_main.c    |    4 +++
 2 files changed, 38 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
index 3103f0b..1d96bda 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_ethtool.c
@@ -174,6 +174,15 @@ static int e1000_get_settings(struct net_device *netdev,
 
 	ecmd->autoneg = ((hw->media_type == e1000_media_type_fiber) ||
 			 hw->autoneg) ? AUTONEG_ENABLE : AUTONEG_DISABLE;
+
+	/* MDI-X => 1; MDI => 0 */
+	if (hw->media_type == e1000_media_type_copper)
+		ecmd->eth_tp_mdix = (!!adapter->phy_info.mdix_mode ?
+							ETH_TP_MDI_X :
+							ETH_TP_MDI);
+	else
+		ecmd->eth_tp_mdix = ETH_TP_MDI_INVALID;
+
 	return 0;
 }
 
@@ -183,6 +192,22 @@ static int e1000_set_settings(struct net_device *netdev,
 	struct e1000_adapter *adapter = netdev_priv(netdev);
 	struct e1000_hw *hw = &adapter->hw;
 
+	/*
+	 * 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->media_type != e1000_media_type_copper)
+			return -EOPNOTSUPP;
+
+		if ((ecmd->eth_tp_mdix_ctrl != ETH_TP_MDI_AUTO) &&
+		    (ecmd->autoneg != AUTONEG_ENABLE)) {
+			e_err(drv, "forcing MDI/MDI-X state is not supported when link speed and/or duplex are forced\n");
+			return -EINVAL;
+		}
+	}
+
 	while (test_and_set_bit(__E1000_RESETTING, &adapter->flags))
 		msleep(1);
 
@@ -199,12 +224,21 @@ static int e1000_set_settings(struct net_device *netdev,
 		ecmd->advertising = hw->autoneg_advertised;
 	} else {
 		u32 speed = ethtool_cmd_speed(ecmd);
+		/* calling this overrides forced MDI setting */
 		if (e1000_set_spd_dplx(adapter, speed, ecmd->duplex)) {
 			clear_bit(__E1000_RESETTING, &adapter->flags);
 			return -EINVAL;
 		}
 	}
 
+	/* MDI-X => 2; MDI => 1; Auto => 3 */
+	if (ecmd->eth_tp_mdix_ctrl) {
+		if (ecmd->eth_tp_mdix_ctrl == ETH_TP_MDI_AUTO)
+			hw->mdix = AUTO_ALL_MODES;
+		else
+			hw->mdix = ecmd->eth_tp_mdix_ctrl;
+	}
+
 	/* reset the link */
 
 	if (netif_running(adapter->netdev)) {
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
index 3bfbb8d..0ae2fcf 100644
--- a/drivers/net/ethernet/intel/e1000/e1000_main.c
+++ b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -4939,6 +4939,10 @@ int e1000_set_spd_dplx(struct e1000_adapter *adapter, u32 spd, u8 dplx)
 	default:
 		goto err_inval;
 	}
+
+	/* clear MDI, MDI(-X) override is only allowed when autoneg enabled */
+	hw->mdix = AUTO_ALL_MODES;
+
 	return 0;
 
 err_inval:
-- 
1.7.10.4