net: dsa: Allow switch drivers to indicate number of TX queues

Let switch drivers indicate how many TX queues they support. Some
switches, such as Broadcom Starfighter 2 are designed with 8 egress
queues. Future changes will allow us to leverage the queue mapping and
direct the transmission towards a particular queue.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -243,6 +243,9 @@ struct dsa_switch {
 	/* devlink used to represent this switch device */
 	struct devlink		*devlink;
 
+	/* Number of switch port queues */
+	unsigned int		num_tx_queues;
+
 	/* Dynamically allocated ports, keep last */
 	size_t num_ports;
 	struct dsa_port ports[];

net/dsa/slave.c

@@ -1259,8 +1259,12 @@ int dsa_slave_create(struct dsa_port *port, const char *name)
 	cpu_dp = ds->dst->cpu_dp;
 	master = cpu_dp->netdev;
 
-	slave_dev = alloc_netdev(sizeof(struct dsa_slave_priv), name,
-				 NET_NAME_UNKNOWN, ether_setup);
+	if (!ds->num_tx_queues)
+		ds->num_tx_queues = 1;
+
+	slave_dev = alloc_netdev_mqs(sizeof(struct dsa_slave_priv), name,
+				     NET_NAME_UNKNOWN, ether_setup,
+				     ds->num_tx_queues, 1);
 	if (slave_dev == NULL)
 		return -ENOMEM;