enic: add sw timestamp support

Add ethtool ops to advertise sw timestamping.
Call skb_tx_timestamp() just before ringing the wq doorbell.

Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cisco/enic/enic_ethtool.c

@@ -18,6 +18,7 @@
 
 #include <linux/netdevice.h>
 #include <linux/ethtool.h>
+#include <linux/net_tstamp.h>
 
 #include "enic_res.h"
 #include "enic.h"
@@ -578,6 +579,16 @@ static int enic_set_rxfh(struct net_device *netdev, const u32 *indir,
 	return __enic_set_rsskey(enic);
 }
 
+static int enic_get_ts_info(struct net_device *netdev,
+			    struct ethtool_ts_info *info)
+{
+	info->so_timestamping = SOF_TIMESTAMPING_TX_SOFTWARE |
+				SOF_TIMESTAMPING_RX_SOFTWARE |
+				SOF_TIMESTAMPING_SOFTWARE;
+
+	return 0;
+}
+
 static const struct ethtool_ops enic_ethtool_ops = {
 	.get_drvinfo = enic_get_drvinfo,
 	.get_msglevel = enic_get_msglevel,
@@ -597,6 +608,7 @@ static const struct ethtool_ops enic_ethtool_ops = {
 	.get_rxfh = enic_get_rxfh,
 	.set_rxfh = enic_set_rxfh,
 	.get_link_ksettings = enic_get_ksettings,
+	.get_ts_info = enic_get_ts_info,
 };
 
 void enic_set_ethtool_ops(struct net_device *netdev)

drivers/net/ethernet/cisco/enic/enic_main.c

@@ -856,6 +856,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
 
 	if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
 		netif_tx_stop_queue(txq);
+	skb_tx_timestamp(skb);
 	if (!skb->xmit_more || netif_xmit_stopped(txq))
 		vnic_wq_doorbell(wq);