[PATCH AUTOSEL 5.2 172/185] e1000e: add workaround for possible stalled packet

Sasha Levin
2019-09-22T19:20:59Z

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 cdae0efde8e64..7998a73b6a0fa 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -1429,6 +1429,16 @@ 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 eb09c755fa172..1502895eb45dd 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.h
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.h
@@ -210,7 +210,7 @@

/* 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