net: arc_emac: Add support for ndo_do_ioctl net_device_ops operation

This operation is required for handling ioctl commands like SIOCGMIIREG,
when debugging MDIO registers from userspace.

This commit adds support for this operation.
Signed-off-by: Romain Perier <romain.perier@collabora.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/arc/emac_main.c

@@ -720,6 +720,18 @@ static int arc_emac_set_address(struct net_device *ndev, void *p)
 	return 0;
 }
 
+static int arc_emac_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
+{
+	if (!netif_running(dev))
+		return -EINVAL;
+
+	if (!dev->phydev)
+		return -ENODEV;
+
+	return phy_mii_ioctl(dev->phydev, rq, cmd);
+}
+
+
 static const struct net_device_ops arc_emac_netdev_ops = {
 	.ndo_open		= arc_emac_open,
 	.ndo_stop		= arc_emac_stop,
@@ -727,6 +739,7 @@ static const struct net_device_ops arc_emac_netdev_ops = {
 	.ndo_set_mac_address	= arc_emac_set_address,
 	.ndo_get_stats		= arc_emac_stats,
 	.ndo_set_rx_mode	= arc_emac_set_rx_mode,
+	.ndo_do_ioctl		= arc_emac_ioctl,
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller	= arc_emac_poll_controller,
 #endif