[PATCH AUTOSEL 4.9 56/60] e1000e: add workaround for possible stalled packet

[Sasha Levin <sashal@kernel.org>]

From: Kai-Heng Feng <kai.heng.feng@canonical.com>

[ Upstream commit e5e9a2ecfe780975820e157b922edee715710b66 ]

This works around a possible stalled packet issue, which may occur due to
clock recovery from the PCH being too slow, when the LAN is transitioning
from K1 at 1G link speed.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204057

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/e1000e/ich8lan.c | 10 ++++++++++
 drivers/net/ethernet/intel/e1000e/ich8lan.h |  2 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index dc7d671b903c5..625008e8cb0df 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -1447,6 +1447,16 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
 			else
 				phy_reg |= 0xFA;
 			e1e_wphy_locked(hw, I217_PLL_CLOCK_GATE_REG, phy_reg);
+
+			if (speed == SPEED_1000) {
+				hw->phy.ops.read_reg_locked(hw, HV_PM_CTRL,
+							    &phy_reg);
+
+				phy_reg |= HV_PM_CTRL_K1_CLK_REQ;
+
+				hw->phy.ops.write_reg_locked(hw, HV_PM_CTRL,
+							     phy_reg);
+			}
 		}
 		hw->phy.ops.release(hw);
 
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.h b/drivers/net/ethernet/intel/e1000e/ich8lan.h
index 67163ca898ba2..6374c8fc76a8d 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.h
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.h
@@ -227,7 +227,7 @@
 
 /* PHY Power Management Control */
 #define HV_PM_CTRL		PHY_REG(770, 17)
-#define HV_PM_CTRL_PLL_STOP_IN_K1_GIGA	0x100
+#define HV_PM_CTRL_K1_CLK_REQ		0x200
 #define HV_PM_CTRL_K1_ENABLE		0x4000
 
 #define I217_PLL_CLOCK_GATE_REG	PHY_REG(772, 28)
-- 
2.20.1