ixgbe: convert low_water into an array

Since fc.high_water is an array, we should treat low_water as an array
also. This allows the algorithm to output different values for different
TCs, and then we can distinguish between them. In addition, this patch
changes one path that didn't honor the return value from ixgbe_setup_fc.

Reported-by: Aaron Salter <aaron.k.salter@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 22 insertions, 13 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
index 24fba39e194e..6cc148b7c132 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.c
@@ -271,6 +271,7 @@ out:
  **/
 s32 ixgbe_start_hw_generic(struct ixgbe_hw *hw)
 {
+	s32 ret_val;
 	u32 ctrl_ext;
 
 	/* Set the media type */
@@ -292,12 +293,15 @@ s32 ixgbe_start_hw_generic(struct ixgbe_hw *hw)
 	IXGBE_WRITE_FLUSH(hw);
 
 	/* Setup flow control */
-	ixgbe_setup_fc(hw);
+	ret_val = ixgbe_setup_fc(hw);
+	if (!ret_val)
+		goto out;
 
 	/* Clear adapter stopped flag */
 	hw->adapter_stopped = false;
 
-	return 0;
+out:
+	return ret_val;
 }
 
 /**
@@ -2106,19 +2110,25 @@ s32 ixgbe_fc_enable_generic(struct ixgbe_hw *hw)
 	u32 fcrtl, fcrth;
 	int i;
 
-	/*
-	 * Validate the water mark configuration for packet buffer 0.  Zero
-	 * water marks indicate that the packet buffer was not configured
-	 * and the watermarks for packet buffer 0 should always be configured.
-	 */
-	if (!hw->fc.low_water ||
-	    !hw->fc.high_water[0] ||
-	    !hw->fc.pause_time) {
-		hw_dbg(hw, "Invalid water mark configuration\n");
+	/* Validate the water mark configuration. */
+	if (!hw->fc.pause_time) {
 		ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
 		goto out;
 	}
 
+	/* Low water mark of zero causes XOFF floods */
+	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
+		if ((hw->fc.current_mode & ixgbe_fc_tx_pause) &&
+		    hw->fc.high_water[i]) {
+			if (!hw->fc.low_water[i] ||
+			    hw->fc.low_water[i] >= hw->fc.high_water[i]) {
+				hw_dbg(hw, "Invalid water mark configuration\n");
+				ret_val = IXGBE_ERR_INVALID_LINK_SETTINGS;
+				goto out;
+			}
+		}
+	}
+
 	/* Negotiate the fc mode to use */
 	ixgbe_fc_autoneg(hw);
 
@@ -2181,12 +2191,11 @@ s32 ixgbe_fc_enable_generic(struct ixgbe_hw *hw)
 	IXGBE_WRITE_REG(hw, IXGBE_MFLCN, mflcn_reg);
 	IXGBE_WRITE_REG(hw, IXGBE_FCCFG, fccfg_reg);
 
-	fcrtl = (hw->fc.low_water << 10) | IXGBE_FCRTL_XONE;
-
 	/* Set up and enable Rx high/low water mark thresholds, enable XON. */
 	for (i = 0; i < MAX_TRAFFIC_CLASS; i++) {
 		if ((hw->fc.current_mode & ixgbe_fc_tx_pause) &&
 		    hw->fc.high_water[i]) {
+			fcrtl = (hw->fc.low_water[i] << 10) | IXGBE_FCRTL_XONE;
 			IXGBE_WRITE_REG(hw, IXGBE_FCRTL_82599(i), fcrtl);
 			fcrth = (hw->fc.high_water[i] << 10) | IXGBE_FCRTH_FCEN;
 		} else {