ixgbe: PFC not cleared on X540 devices

X540 devices do not clear PFC before sets. This results in
the device possibly responding to PFC frames that the user
has disabled. Although it would also be wrong for the peer
to be transmitting these frames. Now we clear the register
before set.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

2 files changed, 4 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82599.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82599.c
index ade98200288c..d64fb872978e 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82599.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_dcb_82599.c
@@ -252,8 +252,10 @@ s32 ixgbe_dcb_config_pfc_82599(struct ixgbe_hw *hw, u8 pfc_en)
                 reg &= ~IXGBE_MFLCN_RFCE;
                 reg |= IXGBE_MFLCN_RPFCE | IXGBE_MFLCN_DPF;
 
-                if (hw->mac.type == ixgbe_mac_X540)
+                if (hw->mac.type == ixgbe_mac_X540) {
+                        reg &= ~IXGBE_MFLCN_RPFCE_MASK;
                         reg |= pfc_en << IXGBE_MFLCN_RPFCE_SHIFT;
+                }
 
                 IXGBE_WRITE_REG(hw, IXGBE_MFLCN, reg);
 
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
index e0d970ebab7a..9f618ee7d333 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_type.h
@@ -1834,6 +1834,7 @@ enum {
 #define IXGBE_MFLCN_DPF         0x00000002 /* Discard Pause Frame */
 #define IXGBE_MFLCN_RPFCE       0x00000004 /* Receive Priority FC Enable */
 #define IXGBE_MFLCN_RFCE        0x00000008 /* Receive FC Enable */
+#define IXGBE_MFLCN_RPFCE_MASK  0x00000FE0 /* Receive FC Mask */
 
 #define IXGBE_MFLCN_RPFCE_SHIFT          4