3c59x: Add software timestamping

Added software timestamping ability. Tested with linuxptp and synchronized
clocks to an average of less than 200 microseconds on 10 megabit ethernet.

Tested on both Vortex and Boomerang models.
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/3com/3c59x.c

@@ -2079,10 +2079,12 @@ vortex_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		iowrite16(len, ioaddr + Wn7_MasterLen);
 		spin_unlock_irq(&vp->window_lock);
 		vp->tx_skb = skb;
+		skb_tx_timestamp(skb);
 		iowrite16(StartDMADown, ioaddr + EL3_CMD);
 		/* netif_wake_queue() will be called at the DMADone interrupt. */
 	} else {
 		/* ... and the packet rounded to a doubleword. */
+		skb_tx_timestamp(skb);
 		iowrite32_rep(ioaddr + TX_FIFO, skb->data, (skb->len + 3) >> 2);
 		dev_kfree_skb (skb);
 		if (ioread16(ioaddr + TxFree) > 1536) {
@@ -2212,6 +2214,7 @@ boomerang_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		prev_entry->status &= cpu_to_le32(~TxIntrUploaded);
 #endif
 	}
+	skb_tx_timestamp(skb);
 	iowrite16(DownUnstall, ioaddr + EL3_CMD);
 	spin_unlock_irqrestore(&vp->lock, flags);
 	return NETDEV_TX_OK;
@@ -2986,6 +2989,7 @@ static const struct ethtool_ops vortex_ethtool_ops = {
 	.nway_reset             = vortex_nway_reset,
 	.get_wol                = vortex_get_wol,
 	.set_wol                = vortex_set_wol,
+	.get_ts_info		= ethtool_op_get_ts_info,
 };
 
 #ifdef CONFIG_PCI