e1000e: fix PHY init workarounds for i217/i218

Toggling the LANPHYPC Value bit cycles the power on the PHY and sets it
back to power-on defaults.  This includes setting it's MAC-PHY messaging
mode to use the PCIe-like interconnect, so the MAC must also be set back
from SMBus mode to PCIe mode otherwise the PHY can be inaccessible.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NJeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/ich8lan.c

@@ -426,6 +426,15 @@ static s32 e1000_init_phy_workarounds_pchlan(struct e1000_hw *hw)
 		mac_reg |= E1000_FEXTNVM3_PHY_CFG_COUNTER_50MSEC;
 		ew32(FEXTNVM3, mac_reg);
 
+		if (hw->mac.type == e1000_pch_lpt) {
+			/* Toggling LANPHYPC brings the PHY out of SMBus mode
+			 * So ensure that the MAC is also out of SMBus mode
+			 */
+			mac_reg = er32(CTRL_EXT);
+			mac_reg &= ~E1000_CTRL_EXT_FORCE_SMBUS;
+			ew32(CTRL_EXT, mac_reg);
+		}
+
 		/* Toggle LANPHYPC Value bit */
 		mac_reg = er32(CTRL);
 		mac_reg |= E1000_CTRL_LANPHYPC_OVERRIDE;