net: dsa: Refactor selection of tag ops into a function

Replace the two switch statements with an array lookup, and store the
result in the dsa tree structure. The drivers no longer need to know
the selected tag protocol, so remove it from the dsa switch structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/dsa.h b/include/net/dsa.h
index b666f27..bd6ecaa 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -26,6 +26,7 @@
 	DSA_TAG_PROTO_TRAILER,
 	DSA_TAG_PROTO_EDSA,
 	DSA_TAG_PROTO_BRCM,
+	DSA_TAG_LAST,		/* MUST BE LAST */
 };
 
 #define DSA_MAX_SWITCHES	4
@@ -99,7 +100,6 @@
 				       struct net_device *dev,
 				       struct packet_type *pt,
 				       struct net_device *orig_dev);
-	enum dsa_tag_protocol	tag_protocol;
 
 	/*
 	 * Original copy of the master netdev ethtool_ops
@@ -116,6 +116,12 @@
 	 * Data for the individual switch chips.
 	 */
 	struct dsa_switch	*ds[DSA_MAX_SWITCHES];
+
+	/*
+	 * Tagging protocol operations for adding and removing an
+	 * encapsulation tag.
+	 */
+	const struct dsa_device_ops *tag_ops;
 };
 
 struct dsa_port {
diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 7140de4..221ebde 100644
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -29,6 +29,33 @@
 
 char dsa_driver_version[] = "0.1";
 
+static struct sk_buff *dsa_slave_notag_xmit(struct sk_buff *skb,
+					    struct net_device *dev)
+{
+	/* Just return the original SKB */
+	return skb;
+}
+
+static const struct dsa_device_ops none_ops = {
+	.xmit	= dsa_slave_notag_xmit,
+	.rcv	= NULL,
+};
+
+const struct dsa_device_ops *dsa_device_ops[DSA_TAG_LAST] = {
+#ifdef CONFIG_NET_DSA_TAG_DSA
+	[DSA_TAG_PROTO_DSA] = &dsa_netdev_ops,
+#endif
+#ifdef CONFIG_NET_DSA_TAG_EDSA
+	[DSA_TAG_PROTO_EDSA] = &edsa_netdev_ops,
+#endif
+#ifdef CONFIG_NET_DSA_TAG_TRAILER
+	[DSA_TAG_PROTO_TRAILER] = &trailer_netdev_ops,
+#endif
+#ifdef CONFIG_NET_DSA_TAG_BRCM
+	[DSA_TAG_PROTO_BRCM] = &brcm_netdev_ops,
+#endif
+	[DSA_TAG_PROTO_NONE] = &none_ops,
+};
 
 /* switch driver registration ***********************************************/
 static DEFINE_MUTEX(dsa_switch_drivers_mutex);
@@ -225,6 +252,20 @@
 	return 0;
 }
 
+const struct dsa_device_ops *dsa_resolve_tag_protocol(int tag_protocol)
+{
+	const struct dsa_device_ops *ops;
+
+	if (tag_protocol >= DSA_TAG_LAST)
+		return ERR_PTR(-EINVAL);
+	ops = dsa_device_ops[tag_protocol];
+
+	if (!ops)
+		return ERR_PTR(-ENOPROTOOPT);
+
+	return ops;
+}
+
 static int dsa_switch_setup_one(struct dsa_switch *ds, struct device *parent)
 {
 	struct dsa_switch_driver *drv = ds->drv;
@@ -277,35 +318,13 @@
 	 * switch.
 	 */
 	if (dst->cpu_switch == index) {
-		switch (drv->tag_protocol) {
-#ifdef CONFIG_NET_DSA_TAG_DSA
-		case DSA_TAG_PROTO_DSA:
-			dst->rcv = dsa_netdev_ops.rcv;
-			break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_EDSA
-		case DSA_TAG_PROTO_EDSA:
-			dst->rcv = edsa_netdev_ops.rcv;
-			break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-		case DSA_TAG_PROTO_TRAILER:
-			dst->rcv = trailer_netdev_ops.rcv;
-			break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_BRCM
-		case DSA_TAG_PROTO_BRCM:
-			dst->rcv = brcm_netdev_ops.rcv;
-			break;
-#endif
-		case DSA_TAG_PROTO_NONE:
-			break;
-		default:
-			ret = -ENOPROTOOPT;
+		dst->tag_ops = dsa_resolve_tag_protocol(drv->tag_protocol);
+		if (IS_ERR(dst->tag_ops)) {
+			ret = PTR_ERR(dst->tag_ops);
 			goto out;
 		}
 
-		dst->tag_protocol = drv->tag_protocol;
+		dst->rcv = dst->tag_ops->rcv;
 	}
 
 	memcpy(ds->rtable, cd->rtable, sizeof(ds->rtable));
diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index dbea5d9..72f7b89 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h
@@ -53,6 +53,7 @@
 int dsa_cpu_dsa_setup(struct dsa_switch *ds, struct device *dev,
 		      struct device_node *port_dn, int port);
 void dsa_cpu_dsa_destroy(struct device_node *port_dn);
+const struct dsa_device_ops *dsa_resolve_tag_protocol(int tag_protocol);
 
 /* slave.c */
 extern const struct dsa_device_ops notag_netdev_ops;
diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 52f1183..35e5f0f 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -521,14 +521,6 @@
 	return NETDEV_TX_OK;
 }
 
-static struct sk_buff *dsa_slave_notag_xmit(struct sk_buff *skb,
-					    struct net_device *dev)
-{
-	/* Just return the original SKB */
-	return skb;
-}
-
-
 /* ethtool operations *******************************************************/
 static int
 dsa_slave_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
@@ -1151,32 +1143,7 @@
 	p = netdev_priv(slave_dev);
 	p->parent = ds;
 	p->port = port;
-
-	switch (ds->dst->tag_protocol) {
-#ifdef CONFIG_NET_DSA_TAG_DSA
-	case DSA_TAG_PROTO_DSA:
-		p->xmit = dsa_netdev_ops.xmit;
-		break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_EDSA
-	case DSA_TAG_PROTO_EDSA:
-		p->xmit = edsa_netdev_ops.xmit;
-		break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_TRAILER
-	case DSA_TAG_PROTO_TRAILER:
-		p->xmit = trailer_netdev_ops.xmit;
-		break;
-#endif
-#ifdef CONFIG_NET_DSA_TAG_BRCM
-	case DSA_TAG_PROTO_BRCM:
-		p->xmit = brcm_netdev_ops.xmit;
-		break;
-#endif
-	default:
-		p->xmit	= dsa_slave_notag_xmit;
-		break;
-	}
+	p->xmit = dst->tag_ops->xmit;
 
 	p->old_pause = -1;
 	p->old_link = -1;