diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 99a4b990939f..587afe7be689 100644
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -131,8 +131,6 @@ static void free_skb_resources(struct gfar_private *priv);
 static void gfar_set_multi(struct net_device *dev);
 static void gfar_set_hash_for_addr(struct net_device *dev, u8 *addr);
 static void gfar_configure_serdes(struct net_device *dev);
-extern int gfar_local_mdio_write(struct gfar_mii __iomem *regs, int mii_id, int regnum, u16 value);
-extern int gfar_local_mdio_read(struct gfar_mii __iomem *regs, int mii_id, int regnum);
 #ifdef CONFIG_GFAR_NAPI
 static int gfar_poll(struct napi_struct *napi, int budget);
 #endif
@@ -477,24 +475,30 @@ static int init_phy(struct net_device *dev)
 	return 0;
 }
 
+/*
+ * Initialize TBI PHY interface for communicating with the
+ * SERDES lynx PHY on the chip.  We communicate with this PHY
+ * through the MDIO bus on each controller, treating it as a
+ * "normal" PHY at the address found in the TBIPA register.  We assume
+ * that the TBIPA register is valid.  Either the MDIO bus code will set
+ * it to a value that doesn't conflict with other PHYs on the bus, or the
+ * value doesn't matter, as there are no other PHYs on the bus.
+ */
 static void gfar_configure_serdes(struct net_device *dev)
 {
 	struct gfar_private *priv = netdev_priv(dev);
 	struct gfar_mii __iomem *regs =
 			(void __iomem *)&priv->regs->gfar_mii_regs;
+	int tbipa = gfar_read(&priv->regs->tbipa);
 
-	/* Initialise TBI i/f to communicate with serdes (lynx phy) */
+	/* Single clk mode, mii mode off(for serdes communication) */
+	gfar_local_mdio_write(regs, tbipa, MII_TBICON, TBICON_CLK_SELECT);
 
-	/* Single clk mode, mii mode off(for aerdes communication) */
-	gfar_local_mdio_write(regs, TBIPA_VALUE, MII_TBICON, TBICON_CLK_SELECT);
-
-	/* Supported pause and full-duplex, no half-duplex */
-	gfar_local_mdio_write(regs, TBIPA_VALUE, MII_ADVERTISE,
+	gfar_local_mdio_write(regs, tbipa, MII_ADVERTISE,
 			ADVERTISE_1000XFULL | ADVERTISE_1000XPAUSE |
 			ADVERTISE_1000XPSE_ASYM);
 
-	/* ANEG enable, restart ANEG, full duplex mode, speed[1] set */
-	gfar_local_mdio_write(regs, TBIPA_VALUE, MII_BMCR, BMCR_ANENABLE |
+	gfar_local_mdio_write(regs, tbipa, MII_BMCR, BMCR_ANENABLE |
 			BMCR_ANRESTART | BMCR_FULLDPLX | BMCR_SPEED1000);
 }
 
@@ -541,9 +545,6 @@ static void init_registers(struct net_device *dev)
 
 	/* Initialize the Minimum Frame Length Register */
 	gfar_write(&priv->regs->minflr, MINFLR_INIT_SETTINGS);
-
-	/* Assign the TBI an address which won't conflict with the PHYs */
-	gfar_write(&priv->regs->tbipa, TBIPA_VALUE);
 }
 
 
diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index 0d0883609469..fd487be3993e 100644
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -137,7 +137,6 @@ extern const char gfar_driver_version[];
 #define DEFAULT_RXCOUNT	0
 #endif /* CONFIG_GFAR_NAPI */
 
-#define TBIPA_VALUE		0x1f
 #define MIIMCFG_INIT_VALUE	0x00000007
 #define MIIMCFG_RESET           0x80000000
 #define MIIMIND_BUSY            0x00000001
diff --git a/drivers/net/gianfar_mii.c b/drivers/net/gianfar_mii.c
index b8898927236a..ebcfb27a904e 100644
--- a/drivers/net/gianfar_mii.c
+++ b/drivers/net/gianfar_mii.c
@@ -78,7 +78,6 @@ int gfar_local_mdio_write(struct gfar_mii __iomem *regs, int mii_id,
  * same as system mdio bus, used for controlling the external PHYs, for eg.
  */
 int gfar_local_mdio_read(struct gfar_mii __iomem *regs, int mii_id, int regnum)
-
 {
 	u16 value;
 
@@ -122,7 +121,7 @@ int gfar_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 }
 
 /* Reset the MIIM registers, and wait for the bus to free */
-int gfar_mdio_reset(struct mii_bus *bus)
+static int gfar_mdio_reset(struct mii_bus *bus)
 {
 	struct gfar_mii __iomem *regs = (void __iomem *)bus->priv;
 	unsigned int timeout = PHY_INIT_TIMEOUT;
@@ -152,14 +151,15 @@ int gfar_mdio_reset(struct mii_bus *bus)
 }
 
 
-int gfar_mdio_probe(struct device *dev)
+static int gfar_mdio_probe(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct gianfar_mdio_data *pdata;
 	struct gfar_mii __iomem *regs;
+	struct gfar __iomem *enet_regs;
 	struct mii_bus *new_bus;
 	struct resource *r;
-	int err = 0;
+	int i, err = 0;
 
 	if (NULL == dev)
 		return -EINVAL;
@@ -199,6 +199,34 @@ int gfar_mdio_probe(struct device *dev)
 	new_bus->dev = dev;
 	dev_set_drvdata(dev, new_bus);
 
+	/*
+	 * This is mildly evil, but so is our hardware for doing this.
+	 * Also, we have to cast back to struct gfar_mii because of
+	 * definition weirdness done in gianfar.h.
+	 */
+	enet_regs = (struct gfar __iomem *)
+		((char *)regs - offsetof(struct gfar, gfar_mii_regs));
+
+	/* Scan the bus, looking for an empty spot for TBIPA */
+	gfar_write(&enet_regs->tbipa, 0);
+	for (i = PHY_MAX_ADDR; i > 0; i--) {
+		u32 phy_id;
+		int r;
+
+		r = get_phy_id(new_bus, i, &phy_id);
+		if (r)
+			return r;
+
+		if (phy_id == 0xffffffff)
+			break;
+	}
+
+	/* The bus is full.  We don't support using 31 PHYs, sorry */
+	if (i == 0)
+		return -EBUSY;
+
+	gfar_write(&enet_regs->tbipa, i);
+
 	err = mdiobus_register(new_bus);
 
 	if (0 != err) {
@@ -218,7 +246,7 @@ int gfar_mdio_probe(struct device *dev)
 }
 
 
-int gfar_mdio_remove(struct device *dev)
+static int gfar_mdio_remove(struct device *dev)
 {
 	struct mii_bus *bus = dev_get_drvdata(dev);
 
diff --git a/drivers/net/gianfar_mii.h b/drivers/net/gianfar_mii.h
index b373091c7031..2af28b16a0e2 100644
--- a/drivers/net/gianfar_mii.h
+++ b/drivers/net/gianfar_mii.h
@@ -41,6 +41,9 @@ struct gfar_mii {
 
 int gfar_mdio_read(struct mii_bus *bus, int mii_id, int regnum);
 int gfar_mdio_write(struct mii_bus *bus, int mii_id, int regnum, u16 value);
+int gfar_local_mdio_write(struct gfar_mii __iomem *regs, int mii_id,
+			  int regnum, u16 value);
+int gfar_local_mdio_read(struct gfar_mii __iomem *regs, int mii_id, int regnum);
 int __init gfar_mdio_init(void);
 void gfar_mdio_exit(void);
 #endif /* GIANFAR_PHY_H */