netdev - [net-next 02/12] ixgbe: fix read-modify-write in x550 phy setup

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Date:   Fri, 23 Mar 2018 16:16:21 -0700
From:   Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:     davem@...emloft.net
Cc:     Paul Greenwalt <paul.greenwalt@...el.com>, netdev@...r.kernel.org,
        nhorman@...hat.com, sassmann@...hat.com, jogreene@...hat.com,
        Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next 02/12] ixgbe: fix read-modify-write in x550 phy setup

From: Paul Greenwalt <paul.greenwalt@...el.com>

Replaced an assignment operation with an OR operation.

The variable assignment was overwriting the value read from the PHY
register. The OR operation sets only the intended register bits.

The bits that were being overwritten are reserved, so the assignment had no
functional impact.

Reported by: Shannon Nelson <shannon.nelson@...cle.com>
Signed-off-by: Paul Greenwalt <paul.greenwalt@...el.com>
Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
index f470d0204771..3123267dfba9 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
@@ -1847,9 +1847,9 @@ ixgbe_setup_mac_link_sfp_x550a(struct ixgbe_hw *hw, ixgbe_link_speed speed,
 			 (IXGBE_CS4227_EDC_MODE_SR << 1));
 
 	if (setup_linear)
-		reg_phy_ext = (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 1;
+		reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 1;
 	else
-		reg_phy_ext = (IXGBE_CS4227_EDC_MODE_SR << 1) | 1;
+		reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_SR << 1) | 1;
 
 	ret_val = hw->phy.ops.write_reg(hw, reg_slice,
 					IXGBE_MDIO_ZERO_DEV_TYPE, reg_phy_ext);
-- 
2.14.3