e1000e: workaround for packet drop on 82579 at 100Mbps

BugLink: http://bugs.launchpad.net/bugs/870127

The MAC can drop short packets when the PHY detects noise on the line at
100Mbps due to a timing issue.  Workaround the issue by increasing the PLL
counter so the PHY properly recognizes the synchronization pattern from the
MAC.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit 0ed013e28fe853244f4972cf18d8e2bd62eeb8fc)

Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 14 insertions, 5 deletions

diff --git a/drivers/net/e1000e/ich8lan.c b/drivers/net/e1000e/ich8lan.c
index 3369d1f6a39..ee77b94834d 100644
--- a/drivers/net/e1000e/ich8lan.c
+++ b/drivers/net/e1000e/ich8lan.c
@@ -137,8 +137,9 @@
 #define HV_PM_CTRL              PHY_REG(770, 17)
 
 /* PHY Low Power Idle Control */
-#define I82579_LPI_CTRL                 PHY_REG(772, 20)
-#define I82579_LPI_CTRL_ENABLE_MASK     0x6000
+#define I82579_LPI_CTRL                         PHY_REG(772, 20)
+#define I82579_LPI_CTRL_ENABLE_MASK             0x6000
+#define I82579_LPI_CTRL_FORCE_PLL_LOCK_COUNT    0x80
 
 /* EMI Registers */
 #define I82579_EMI_ADDR         0x10
@@ -1611,6 +1612,7 @@ static s32 e1000_k1_workaround_lv(struct e1000_hw *hw)
         s32 ret_val = 0;
         u16 status_reg = 0;
         u32 mac_reg;
+        u16 phy_reg;
 
         if (hw->mac.type != e1000_pch2lan)
                 goto out;
@@ -1625,12 +1627,19 @@ static s32 e1000_k1_workaround_lv(struct e1000_hw *hw)
                 mac_reg = er32(FEXTNVM4);
                 mac_reg &= ~E1000_FEXTNVM4_BEACON_DURATION_MASK;
 
-                if (status_reg & HV_M_STATUS_SPEED_1000)
+                ret_val = e1e_rphy(hw, I82579_LPI_CTRL, &phy_reg);
+                if (ret_val)
+                        goto out;
+
+                if (status_reg & HV_M_STATUS_SPEED_1000) {
                         mac_reg |= E1000_FEXTNVM4_BEACON_DURATION_8USEC;
-                else
+                        phy_reg &= ~I82579_LPI_CTRL_FORCE_PLL_LOCK_COUNT;
+                } else {
                         mac_reg |= E1000_FEXTNVM4_BEACON_DURATION_16USEC;
-
+                        phy_reg |= I82579_LPI_CTRL_FORCE_PLL_LOCK_COUNT;
+                }
                 ew32(FEXTNVM4, mac_reg);
+                ret_val = e1e_wphy(hw, I82579_LPI_CTRL, phy_reg);
         }
 
 out: