[PATCH 4.9 44/93] igb: Workaround for igb i210 firmware issue

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chris J Arges <christopherarges@xxxxxxxxx>

[ Upstream commit 4e684f59d760a2c7c716bb60190783546e2d08a1 ]

Sometimes firmware may not properly initialize I347AT4_PAGE_SELECT causing
the probe of an igb i210 NIC to fail. This patch adds an addition zeroing
of this register during igb_get_phy_id to workaround this issue.

Thanks for Jochen Henneberg for the idea and original patch.

Signed-off-by: Chris J Arges <christopherarges@xxxxxxxxx>
Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/intel/igb/e1000_phy.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/intel/igb/e1000_phy.c
+++ b/drivers/net/ethernet/intel/igb/e1000_phy.c
@@ -77,6 +77,10 @@ s32 igb_get_phy_id(struct e1000_hw *hw)
 	s32 ret_val = 0;
 	u16 phy_id;
 
+	/* ensure PHY page selection to fix misconfigured i210 */
+	if (hw->mac.type == e1000_i210)
+		phy->ops.write_reg(hw, I347AT4_PAGE_SELECT, 0);
+
 	ret_val = phy->ops.read_reg(hw, PHY_ID1, &phy_id);
 	if (ret_val)
 		goto out;