ixgbe: cleanup some register reads

Remove duplicate inc of hwstats->ruc
Introduce separate loops for 8 and 16 register reads.
Consolidate mac checks under one case.
Make sure registers are cleared on read.

Reported-by: Jonathan Lynch <jonathan.lynch@thenowfactory.com>
Signed-off-by: Emil Tantilov <emil.s.tantilov@intel.com>
CC: Jonathan Lynch <jonathan.lynch@thenowfactory.com>
Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index a4103efde363..1e72c00dd7c0 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -5463,20 +5463,21 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
         netdev->stats.tx_packets = packets;
 
         hwstats->crcerrs += IXGBE_READ_REG(hw, IXGBE_CRCERRS);
+
+        /* 8 register reads */
         for (i = 0; i < 8; i++) {
                 /* for packet buffers not used, the register should read 0 */
                 mpc = IXGBE_READ_REG(hw, IXGBE_MPC(i));
                 missed_rx += mpc;
                 hwstats->mpc[i] += mpc;
                 total_mpc += hwstats->mpc[i];
-                if (hw->mac.type == ixgbe_mac_82598EB)
-                        hwstats->rnbc[i] += IXGBE_READ_REG(hw, IXGBE_RNBC(i));
-                hwstats->qptc[i] += IXGBE_READ_REG(hw, IXGBE_QPTC(i));
-                hwstats->qbtc[i] += IXGBE_READ_REG(hw, IXGBE_QBTC(i));
-                hwstats->qprc[i] += IXGBE_READ_REG(hw, IXGBE_QPRC(i));
-                hwstats->qbrc[i] += IXGBE_READ_REG(hw, IXGBE_QBRC(i));
+                hwstats->pxontxc[i] += IXGBE_READ_REG(hw, IXGBE_PXONTXC(i));
+                hwstats->pxofftxc[i] += IXGBE_READ_REG(hw, IXGBE_PXOFFTXC(i));
                 switch (hw->mac.type) {
                 case ixgbe_mac_82598EB:
+                        hwstats->rnbc[i] += IXGBE_READ_REG(hw, IXGBE_RNBC(i));
+                        hwstats->qbtc[i] += IXGBE_READ_REG(hw, IXGBE_QBTC(i));
+                        hwstats->qbrc[i] += IXGBE_READ_REG(hw, IXGBE_QBRC(i));
                         hwstats->pxonrxc[i] +=
                                 IXGBE_READ_REG(hw, IXGBE_PXONRXC(i));
                         break;
@@ -5488,9 +5489,21 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
                 default:
                         break;
                 }
-                hwstats->pxontxc[i] += IXGBE_READ_REG(hw, IXGBE_PXONTXC(i));
-                hwstats->pxofftxc[i] += IXGBE_READ_REG(hw, IXGBE_PXOFFTXC(i));
         }
+
+        /*16 register reads */
+        for (i = 0; i < 16; i++) {
+                hwstats->qptc[i] += IXGBE_READ_REG(hw, IXGBE_QPTC(i));
+                hwstats->qprc[i] += IXGBE_READ_REG(hw, IXGBE_QPRC(i));
+                if ((hw->mac.type == ixgbe_mac_82599EB) ||
+                    (hw->mac.type == ixgbe_mac_X540)) {
+                        hwstats->qbtc[i] += IXGBE_READ_REG(hw, IXGBE_QBTC_L(i));
+                        IXGBE_READ_REG(hw, IXGBE_QBTC_H(i)); /* to clear */
+                        hwstats->qbrc[i] += IXGBE_READ_REG(hw, IXGBE_QBRC_L(i));
+                        IXGBE_READ_REG(hw, IXGBE_QBRC_H(i)); /* to clear */
+                }
+        }
+
         hwstats->gprc += IXGBE_READ_REG(hw, IXGBE_GPRC);
         /* work around hardware counting issue */
         hwstats->gprc -= missed_rx;
@@ -5550,7 +5563,6 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
         hwstats->lxontxc += lxon;
         lxoff = IXGBE_READ_REG(hw, IXGBE_LXOFFTXC);
         hwstats->lxofftxc += lxoff;
-        hwstats->ruc += IXGBE_READ_REG(hw, IXGBE_RUC);
         hwstats->gptc += IXGBE_READ_REG(hw, IXGBE_GPTC);
         hwstats->mptc += IXGBE_READ_REG(hw, IXGBE_MPTC);
         /*