ixgbe: Fix - Do not allow Rx FC on 82598 at 1G due to errata

The 82598 has an erratum that receipt of pause frames at 1G
could lead to a Tx Hang.  To avoid this this patch disables
Rx FC while at 1G speed for all 82598 parts.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/drivers/net/ixgbe/ixgbe_82598.c b/drivers/net/ixgbe/ixgbe_82598.c
index 3103f4165311..35a06b47587b 100644
--- a/drivers/net/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ixgbe/ixgbe_82598.c
@@ -357,12 +357,34 @@ static s32 ixgbe_fc_enable_82598(struct ixgbe_hw *hw, s32 packetbuf_num)
         u32 fctrl_reg;
         u32 rmcs_reg;
         u32 reg;
+        u32 link_speed = 0;
+        bool link_up;
 
 #ifdef CONFIG_DCB
         if (hw->fc.requested_mode == ixgbe_fc_pfc)
                 goto out;
 
 #endif /* CONFIG_DCB */
+        /*
+         * On 82598 having Rx FC on causes resets while doing 1G
+         * so if it's on turn it off once we know link_speed. For
+         * more details see 82598 Specification update.
+         */
+        hw->mac.ops.check_link(hw, &link_speed, &link_up, false);
+        if (link_up && link_speed == IXGBE_LINK_SPEED_1GB_FULL) {
+                switch (hw->fc.requested_mode) {
+                case ixgbe_fc_full:
+                        hw->fc.requested_mode = ixgbe_fc_tx_pause;
+                        break;
+                case ixgbe_fc_rx_pause:
+                        hw->fc.requested_mode = ixgbe_fc_none;
+                        break;
+                default:
+                        /* no change */
+                        break;
+                }
+        }
+
         /* Negotiate the fc mode to use */
         ret_val = ixgbe_fc_autoneg(hw);
         if (ret_val)