dsa: Split ops up, and avoid assigning tag_protocol and receive separately

This change addresses several issues.

First, it was possible to set tag_protocol without setting the ops pointer.
To correct that I have reordered things so that rcv is now populated before
we set tag_protocol.

Second, it didn't make much sense to keep setting the device ops each time a
new slave was registered.  So by moving the receive portion out into root
switch initialization that issue should be addressed.

Third, I wanted to avoid sending tags if the rcv pointer was not registered
so I changed the tag check to verify if the rcv function pointer is set on
the root tree.  If it is then we start sending DSA tagged frames.

Finally I split the device ops pointer in the structures into two spots.  I
placed the rcv function pointer in the root switch since this makes it
easiest to access from there, and I placed the xmit function pointer in the
slave for the same reason.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 98afed4..f90899e 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -12,7 +12,13 @@
 #define __DSA_PRIV_H
 
 #include <linux/phy.h>
-#include <net/dsa.h>
+#include <linux/netdevice.h>
+
+struct dsa_device_ops {
+	netdev_tx_t (*xmit)(struct sk_buff *skb, struct net_device *dev);
+	int (*rcv)(struct sk_buff *skb, struct net_device *dev,
+		   struct packet_type *pt, struct net_device *orig_dev);
+};
 
 struct dsa_slave_priv {
 	/*
@@ -20,6 +26,8 @@
 	 * switch port.
 	 */
 	struct net_device	*dev;
+	netdev_tx_t		(*xmit)(struct sk_buff *skb,
+					struct net_device *dev);
 
 	/*
 	 * Which switch this port is a part of, and the port index
@@ -43,6 +51,7 @@
 extern char dsa_driver_version[];
 
 /* slave.c */
+extern const struct dsa_device_ops notag_netdev_ops;
 void dsa_slave_mii_bus_init(struct dsa_switch *ds);
 struct net_device *dsa_slave_create(struct dsa_switch *ds,
 				    struct device *parent,