net: ethtool: Introduce ethtool_phy_ops

In order to decouple ethtool from its PHY library dependency, define an
ethtool_phy_ops singleton which can be overriden by the PHY library when
it loads with an appropriate set of function pointers.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ethtool/common.c

@@ -2,6 +2,7 @@
 
 #include <linux/net_tstamp.h>
 #include <linux/phy.h>
+#include <linux/rtnetlink.h>
 
 #include "common.h"
 
@@ -373,3 +374,13 @@ int __ethtool_get_ts_info(struct net_device *dev, struct ethtool_ts_info *info)
 
 	return 0;
 }
+
+const struct ethtool_phy_ops *ethtool_phy_ops;
+
+void ethtool_set_ethtool_phy_ops(const struct ethtool_phy_ops *ops)
+{
+	rtnl_lock();
+	ethtool_phy_ops = ops;
+	rtnl_unlock();
+}
+EXPORT_SYMBOL_GPL(ethtool_set_ethtool_phy_ops);