e1000e: implement 82577/579 MDI setting support

In order for e1000e to support MDI setting support via
ethtool this code is needed to allow setting the MDI state
via software.

This is in regards to the related ethtool patch and
fixes bugzilla.kernel.org bug 11998

Signed-off-by: Bruce W Allan <bruce.w.allan@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@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/e1000e/phy.c

@@ -84,8 +84,9 @@ static const u16 e1000_igp_2_cable_length_table[] = {
 #define I82577_PHY_STATUS2_SPEED_1000MBPS 0x0200
 
 /* I82577 PHY Control 2 */
-#define I82577_PHY_CTRL2_AUTO_MDIX        0x0400
-#define I82577_PHY_CTRL2_FORCE_MDI_MDIX   0x0200
+#define I82577_PHY_CTRL2_MANUAL_MDIX      0x0200
+#define I82577_PHY_CTRL2_AUTO_MDI_MDIX    0x0400
+#define I82577_PHY_CTRL2_MDIX_CFG_MASK    0x0600
 
 /* I82577 PHY Diagnostics Status */
 #define I82577_DSTATUS_CABLE_LENGTH       0x03FC
@@ -702,6 +703,32 @@ s32 e1000_copper_link_setup_82577(struct e1000_hw *hw)
 	if (ret_val)
 		return ret_val;
 
+	/* Set MDI/MDIX mode */
+	ret_val = e1e_rphy(hw, I82577_PHY_CTRL_2, &phy_data);
+	if (ret_val)
+		return ret_val;
+	phy_data &= ~I82577_PHY_CTRL2_MDIX_CFG_MASK;
+	/*
+	 * Options:
+	 *   0 - Auto (default)
+	 *   1 - MDI mode
+	 *   2 - MDI-X mode
+	 */
+	switch (hw->phy.mdix) {
+	case 1:
+		break;
+	case 2:
+		phy_data |= I82577_PHY_CTRL2_MANUAL_MDIX;
+		break;
+	case 0:
+	default:
+		phy_data |= I82577_PHY_CTRL2_AUTO_MDI_MDIX;
+		break;
+	}
+	ret_val = e1e_wphy(hw, I82577_PHY_CTRL_2, phy_data);
+	if (ret_val)
+		return ret_val;
+
 	return e1000_set_master_slave_mode(hw);
 }