net: dsa: allow for more complex PHY setups

Modify the DSA slave interface to be bound to an arbitray PHY, not just
the ones that are available as child PHY devices of the switch MDIO bus.

This allows us for instance to have external PHYs connected to a
separate MDIO bus, but yet also connected to a given switch port.

Under certain configurations, the physical port mask might not be a 1:1
mapping to the MII PHYs mask. This is the case, if e.g: Port 1 of the
switch is used and connects to a PHY at a MDIO address different than 1.

Introduce a phys_mii_mask variable which allows driver to implement and
divert their own MDIO read/writes operations for a subset of the MDIO
PHY addresses.

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

include/net/dsa.h

@@ -130,6 +130,7 @@ struct dsa_switch {
 	 */
 	u32			dsa_port_mask;
 	u32			phys_port_mask;
+	u32			phys_mii_mask;
 	struct mii_bus		*slave_mii_bus;
 	struct net_device	*ports[DSA_MAX_PORTS];
 };

net/dsa/dsa.c

@@ -144,6 +144,11 @@ dsa_switch_setup(struct dsa_switch_tree *dst, int index,
 		goto out;
 	}
 
+	/* Make the built-in MII bus mask match the number of ports,
+	 * switch drivers can override this later
+	 */
+	ds->phys_mii_mask = ds->phys_port_mask;
+
 	/*
 	 * If the CPU connects to this switch, set the switch tree
 	 * tagging protocol to the preferred tagging format of this

net/dsa/dsa_priv.h

@@ -33,6 +33,10 @@ struct dsa_slave_priv {
 	 * to this port.
 	 */
 	struct phy_device	*phy;
+	phy_interface_t		phy_interface;
+	int			old_link;
+	int			old_pause;
+	int			old_duplex;
 };
 
 /* dsa.c */

net/dsa/slave.c

@@ -12,14 +12,16 @@
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/phy.h>
+#include <linux/of_net.h>
+#include <linux/of_mdio.h>
 #include "dsa_priv.h"
 
 /* slave mii_bus handling ***************************************************/
 static int dsa_slave_phy_read(struct mii_bus *bus, int addr, int reg)
 {
 	struct dsa_switch *ds = bus->priv;
 
-	if (ds->phys_port_mask & (1 << addr))
+	if (ds->phys_mii_mask & (1 << addr))
 		return ds->drv->phy_read(ds, addr, reg);
 
 	return 0xffff;
@@ -29,7 +31,7 @@ static int dsa_slave_phy_write(struct mii_bus *bus, int addr, int reg, u16 val)
 {
 	struct dsa_switch *ds = bus->priv;
 
-	if (ds->phys_port_mask & (1 << addr))
+	if (ds->phys_mii_mask & (1 << addr))
 		return ds->drv->phy_write(ds, addr, reg, val);
 
 	return 0;
@@ -312,7 +314,70 @@ static const struct net_device_ops dsa_slave_netdev_ops = {
 	.ndo_do_ioctl		= dsa_slave_ioctl,
 };
 
+static void dsa_slave_adjust_link(struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	unsigned int status_changed = 0;
+
+	if (p->old_link != p->phy->link) {
+		status_changed = 1;
+		p->old_link = p->phy->link;
+	}
+
+	if (p->old_duplex != p->phy->duplex) {
+		status_changed = 1;
+		p->old_duplex = p->phy->duplex;
+	}
+
+	if (p->old_pause != p->phy->pause) {
+		status_changed = 1;
+		p->old_pause = p->phy->pause;
+	}
+
+	if (status_changed)
+		phy_print_status(p->phy);
+}
+
 /* slave device setup *******************************************************/
+static void dsa_slave_phy_setup(struct dsa_slave_priv *p,
+				struct net_device *slave_dev)
+{
+	struct dsa_switch *ds = p->parent;
+	struct dsa_chip_data *cd = ds->pd;
+	struct device_node *phy_dn, *port_dn;
+	int ret;
+
+	port_dn = cd->port_dn[p->port];
+	p->phy_interface = of_get_phy_mode(port_dn);
+
+	phy_dn = of_parse_phandle(port_dn, "phy-handle", 0);
+	if (of_phy_is_fixed_link(port_dn)) {
+		/* In the case of a fixed PHY, the DT node associated
+		 * to the fixed PHY is the Port DT node
+		 */
+		ret = of_phy_register_fixed_link(port_dn);
+		if (ret) {
+			pr_err("failed to register fixed PHY\n");
+			return;
+		}
+		phy_dn = port_dn;
+	}
+
+	if (phy_dn)
+		p->phy = of_phy_connect(slave_dev, phy_dn,
+					dsa_slave_adjust_link, 0,
+					p->phy_interface);
+
+	/* We could not connect to a designated PHY, so use the switch internal
+	 * MDIO bus instead
+	 */
+	if (!p->phy)
+		p->phy = ds->slave_mii_bus->phy_map[p->port];
+	else
+		pr_info("attached PHY at address %d [%s]\n",
+			p->phy->addr, p->phy->drv->name);
+}
+
 struct net_device *
 dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 		 int port, char *name)
@@ -361,7 +426,12 @@ dsa_slave_create(struct dsa_switch *ds, struct device *parent,
 	p->dev = slave_dev;
 	p->parent = ds;
 	p->port = port;
-	p->phy = ds->slave_mii_bus->phy_map[port];
+
+	p->old_pause = -1;
+	p->old_link = -1;
+	p->old_duplex = -1;
+
+	dsa_slave_phy_setup(p, slave_dev);
 
 	ret = register_netdev(slave_dev);
 	if (ret) {