ixgbe: fix several counter register errata

Several counters behave differently on 82598 causing them to display
incorrect values. Adjust the accounting so the reported numbers
make sense and do not double count or represent the wrong item.

Signed-off-by: Ayyappan Veeraiyan <ayyappan.veeraiyan@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/ixgbe/ixgbe_main.c

@@ -2026,22 +2026,26 @@ static int ixgbe_close(struct net_device *netdev)
 void ixgbe_update_stats(struct ixgbe_adapter *adapter)
 {
 	struct ixgbe_hw *hw = &adapter->hw;
-	u64 good_rx, missed_rx, bprc;
+	u64 total_mpc = 0;
+	u32 i, missed_rx = 0, mpc, bprc, lxon, lxoff, xon_off_tot;
 
 	adapter->stats.crcerrs += IXGBE_READ_REG(hw, IXGBE_CRCERRS);
-	good_rx = IXGBE_READ_REG(hw, IXGBE_GPRC);
-	missed_rx = IXGBE_READ_REG(hw, IXGBE_MPC(0));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(1));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(2));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(3));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(4));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(5));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(6));
-	missed_rx += IXGBE_READ_REG(hw, IXGBE_MPC(7));
-	adapter->stats.gprc += (good_rx - missed_rx);
-
-	adapter->stats.mpc[0] += missed_rx;
+	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;
+		adapter->stats.mpc[i] += mpc;
+		total_mpc += adapter->stats.mpc[i];
+		adapter->stats.rnbc[i] += IXGBE_READ_REG(hw, IXGBE_RNBC(i));
+	}
+	adapter->stats.gprc += IXGBE_READ_REG(hw, IXGBE_GPRC);
+	/* work around hardware counting issue */
+	adapter->stats.gprc -= missed_rx;
+
+	/* 82598 hardware only has a 32 bit counter in the high register */
 	adapter->stats.gorc += IXGBE_READ_REG(hw, IXGBE_GORCH);
+	adapter->stats.gotc += IXGBE_READ_REG(hw, IXGBE_GOTCH);
+	adapter->stats.tor += IXGBE_READ_REG(hw, IXGBE_TORH);
 	bprc = IXGBE_READ_REG(hw, IXGBE_BPRC);
 	adapter->stats.bprc += bprc;
 	adapter->stats.mprc += IXGBE_READ_REG(hw, IXGBE_MPRC);
@@ -2053,28 +2057,34 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
 	adapter->stats.prc511 += IXGBE_READ_REG(hw, IXGBE_PRC511);
 	adapter->stats.prc1023 += IXGBE_READ_REG(hw, IXGBE_PRC1023);
 	adapter->stats.prc1522 += IXGBE_READ_REG(hw, IXGBE_PRC1522);
-
 	adapter->stats.rlec += IXGBE_READ_REG(hw, IXGBE_RLEC);
 	adapter->stats.lxonrxc += IXGBE_READ_REG(hw, IXGBE_LXONRXC);
-	adapter->stats.lxontxc += IXGBE_READ_REG(hw, IXGBE_LXONTXC);
 	adapter->stats.lxoffrxc += IXGBE_READ_REG(hw, IXGBE_LXOFFRXC);
-	adapter->stats.lxofftxc += IXGBE_READ_REG(hw, IXGBE_LXOFFTXC);
+	lxon = IXGBE_READ_REG(hw, IXGBE_LXONTXC);
+	adapter->stats.lxontxc += lxon;
+	lxoff = IXGBE_READ_REG(hw, IXGBE_LXOFFTXC);
+	adapter->stats.lxofftxc += lxoff;
 	adapter->stats.ruc += IXGBE_READ_REG(hw, IXGBE_RUC);
 	adapter->stats.gptc += IXGBE_READ_REG(hw, IXGBE_GPTC);
-	adapter->stats.gotc += IXGBE_READ_REG(hw, IXGBE_GOTCH);
-	adapter->stats.rnbc[0] += IXGBE_READ_REG(hw, IXGBE_RNBC(0));
+	adapter->stats.mptc += IXGBE_READ_REG(hw, IXGBE_MPTC);
+	/*
+	 * 82598 errata - tx of flow control packets is included in tx counters
+	 */
+	xon_off_tot = lxon + lxoff;
+	adapter->stats.gptc -= xon_off_tot;
+	adapter->stats.mptc -= xon_off_tot;
+	adapter->stats.gotc -= (xon_off_tot * (ETH_ZLEN + ETH_FCS_LEN));
 	adapter->stats.ruc += IXGBE_READ_REG(hw, IXGBE_RUC);
 	adapter->stats.rfc += IXGBE_READ_REG(hw, IXGBE_RFC);
 	adapter->stats.rjc += IXGBE_READ_REG(hw, IXGBE_RJC);
-	adapter->stats.tor += IXGBE_READ_REG(hw, IXGBE_TORH);
 	adapter->stats.tpr += IXGBE_READ_REG(hw, IXGBE_TPR);
 	adapter->stats.ptc64 += IXGBE_READ_REG(hw, IXGBE_PTC64);
+	adapter->stats.ptc64 -= xon_off_tot;
 	adapter->stats.ptc127 += IXGBE_READ_REG(hw, IXGBE_PTC127);
 	adapter->stats.ptc255 += IXGBE_READ_REG(hw, IXGBE_PTC255);
 	adapter->stats.ptc511 += IXGBE_READ_REG(hw, IXGBE_PTC511);
 	adapter->stats.ptc1023 += IXGBE_READ_REG(hw, IXGBE_PTC1023);
 	adapter->stats.ptc1522 += IXGBE_READ_REG(hw, IXGBE_PTC1522);
-	adapter->stats.mptc += IXGBE_READ_REG(hw, IXGBE_MPTC);
 	adapter->stats.bptc += IXGBE_READ_REG(hw, IXGBE_BPTC);
 
 	/* Fill out the OS statistics structure */
@@ -2090,8 +2100,7 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
 	adapter->net_stats.rx_dropped = 0;
 	adapter->net_stats.rx_length_errors = adapter->stats.rlec;
 	adapter->net_stats.rx_crc_errors = adapter->stats.crcerrs;
-	adapter->net_stats.rx_missed_errors = adapter->stats.mpc[0];
-
+	adapter->net_stats.rx_missed_errors = total_mpc;
 }
 
 /**