net: dsa: allow enabling and disable switch ports

Whenever a per-port network device is used/unused, invoke the switch
driver port_enable/port_disable callbacks to allow saving as much power
as possible by disabling unused parts of the switch (RX/TX logic, memory
arrays, PHYs...). We supply a PHY device argument to make sure the
switch driver can act on the PHY device if needed (like putting/taking
the PHY out of deep low power mode).
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/dsa.h

@@ -224,6 +224,14 @@ struct dsa_switch_driver {
 	 */
 	int	(*suspend)(struct dsa_switch *ds);
 	int	(*resume)(struct dsa_switch *ds);
+
+	/*
+	 * Port enable/disable
+	 */
+	int	(*port_enable)(struct dsa_switch *ds, int port,
+			       struct phy_device *phy);
+	void	(*port_disable)(struct dsa_switch *ds, int port,
+				struct phy_device *phy);
 };
 
 void register_switch_driver(struct dsa_switch_driver *type);

net/dsa/slave.c

@@ -62,6 +62,7 @@ static int dsa_slave_open(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 	struct net_device *master = p->parent->dst->master_netdev;
+	struct dsa_switch *ds = p->parent;
 	int err;
 
 	if (!(master->flags & IFF_UP))
@@ -84,11 +85,20 @@ static int dsa_slave_open(struct net_device *dev)
 			goto clear_allmulti;
 	}
 
+	if (ds->drv->port_enable) {
+		err = ds->drv->port_enable(ds, p->port, p->phy);
+		if (err)
+			goto clear_promisc;
+	}
+
 	if (p->phy)
 		phy_start(p->phy);
 
 	return 0;
 
+clear_promisc:
+	if (dev->flags & IFF_PROMISC)
+		dev_set_promiscuity(master, 0);
 clear_allmulti:
 	if (dev->flags & IFF_ALLMULTI)
 		dev_set_allmulti(master, -1);
@@ -103,6 +113,7 @@ static int dsa_slave_close(struct net_device *dev)
 {
 	struct dsa_slave_priv *p = netdev_priv(dev);
 	struct net_device *master = p->parent->dst->master_netdev;
+	struct dsa_switch *ds = p->parent;
 
 	if (p->phy)
 		phy_stop(p->phy);
@@ -117,6 +128,9 @@ static int dsa_slave_close(struct net_device *dev)
 	if (!ether_addr_equal(dev->dev_addr, master->dev_addr))
 		dev_uc_del(master, dev->dev_addr);
 
+	if (ds->drv->port_disable)
+		ds->drv->port_disable(ds, p->port, p->phy);
+
 	return 0;
 }