e1000e: reset MAC-PHY interconnect on 82577/82578 during Sx->S0

During Sx->S0 transitions, the interconnect between the MAC and PHY on
82577/82578 can remain in SMBus mode instead of transitioning to the
PCIe-like mode required during normal operation.  Toggling the LANPHYPC
Value bit essentially resets the interconnect forcing it to the correct
mode.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 5059c22155d9..0bfef8e16a7b 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -83,6 +83,8 @@
 
 
 #define E1000_ICH_FWSM_RSPCIPHY 0x00000040 /* Reset PHY on PCI Reset */
+/* FW established a valid mode */
+#define E1000_ICH_FWSM_FW_VALID         0x00008000
 
 #define E1000_ICH_MNG_IAMT_MODE         0x2
 
@@ -259,6 +261,7 @@ static inline void __ew32flash(struct e1000_hw *hw, unsigned long reg, u32 val)
 static s32 e1000_init_phy_params_pchlan(struct e1000_hw *hw)
 {
         struct e1000_phy_info *phy = &hw->phy;
+        u32 ctrl;
         s32 ret_val = 0;
 
         phy->addr                     = 1;
@@ -274,6 +277,23 @@ static s32 e1000_init_phy_params_pchlan(struct e1000_hw *hw)
         phy->ops.power_down           = e1000_power_down_phy_copper_ich8lan;
         phy->autoneg_mask             = AUTONEG_ADVERTISE_SPEED_DEFAULT;
 
+        if (!(er32(FWSM) & E1000_ICH_FWSM_FW_VALID)) {
+                /*
+                 * The MAC-PHY interconnect may still be in SMBus mode
+                 * after Sx->S0.  Toggle the LANPHYPC Value bit to force
+                 * the interconnect to PCIe mode, but only if there is no
+                 * firmware present otherwise firmware will have done it.
+                 */
+                ctrl = er32(CTRL);
+                ctrl |=  E1000_CTRL_LANPHYPC_OVERRIDE;
+                ctrl &= ~E1000_CTRL_LANPHYPC_VALUE;
+                ew32(CTRL, ctrl);
+                udelay(10);
+                ctrl &= ~E1000_CTRL_LANPHYPC_OVERRIDE;
+                ew32(CTRL, ctrl);
+                msleep(50);
+        }
+
         phy->id = e1000_phy_unknown;
         ret_val = e1000e_get_phy_id(hw);
         if (ret_val)