igc: Expose LPI counters

Completion to commit 900d1e8 ("igc: Add LPI counters")
LPI counters exposed by statistics update method.
A EEE TX LPI counter reflect the transmitter entries EEE (IEEE 802.3az)
into the LPI state. A EEE RX LPI counter reflect the receiver link
partner entries into EEE(IEEE 802.3az) LPI state.

Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/igc/igc_ethtool.c

@@ -321,6 +321,9 @@ static void igc_ethtool_get_regs(struct net_device *netdev,
 
 	for (i = 0; i < 8; i++)
 		regs_buff[205 + i] = rd32(IGC_ETQF(i));
+
+	regs_buff[213] = adapter->stats.tlpic;
+	regs_buff[214] = adapter->stats.rlpic;
 }
 
 static void igc_ethtool_get_wol(struct net_device *netdev,

drivers/net/ethernet/intel/igc/igc_hw.h

@@ -244,6 +244,8 @@ struct igc_hw_stats {
 	u64 prc511;
 	u64 prc1023;
 	u64 prc1522;
+	u64 tlpic;
+	u64 rlpic;
 	u64 gprc;
 	u64 bprc;
 	u64 mprc;

drivers/net/ethernet/intel/igc/igc_main.c

@@ -3683,6 +3683,8 @@ void igc_update_stats(struct igc_adapter *adapter)
 	adapter->stats.prc511 += rd32(IGC_PRC511);
 	adapter->stats.prc1023 += rd32(IGC_PRC1023);
 	adapter->stats.prc1522 += rd32(IGC_PRC1522);
+	adapter->stats.tlpic += rd32(IGC_TLPIC);
+	adapter->stats.rlpic += rd32(IGC_RLPIC);
 
 	mpc = rd32(IGC_MPC);
 	adapter->stats.mpc += mpc;