igb: Add support for SW timestamping

Enable SW timestamping for situations where the user may prefer it over HW
timestamping or there may not be HW timestamping.

Cc: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Matthew Vick <matthew.vick@intel.com>
Acked-by: Jacob Keller <Jacob.e.keller@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb_ethtool.c

@@ -2272,12 +2272,21 @@ static int igb_get_ts_info(struct net_device *dev,
 	struct igb_adapter *adapter = netdev_priv(dev);
 
 	switch (adapter->hw.mac.type) {
+	case e1000_82575:
+		info->so_timestamping =
+			SOF_TIMESTAMPING_TX_SOFTWARE |
+			SOF_TIMESTAMPING_RX_SOFTWARE |
+			SOF_TIMESTAMPING_SOFTWARE;
+		return 0;
 	case e1000_82576:
 	case e1000_82580:
 	case e1000_i350:
 	case e1000_i210:
 	case e1000_i211:
 		info->so_timestamping =
+			SOF_TIMESTAMPING_TX_SOFTWARE |
+			SOF_TIMESTAMPING_RX_SOFTWARE |
+			SOF_TIMESTAMPING_SOFTWARE |
 			SOF_TIMESTAMPING_TX_HARDWARE |
 			SOF_TIMESTAMPING_RX_HARDWARE |
 			SOF_TIMESTAMPING_RAW_HARDWARE;

drivers/net/ethernet/intel/igb/igb_main.c

@@ -4610,6 +4610,8 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
 	first->bytecount = skb->len;
 	first->gso_segs = 1;
 
+	skb_tx_timestamp(skb);
+
 	if (unlikely((skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) &&
 		     !(adapter->ptp_tx_skb))) {
 		skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;