[mii] Add mii_find()

Add the function mii_find() in order to locate the PHY address.

Signed-off-by: Sylvie Barlow <sylvie.c.barlow@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/drivers/net/mii.c

 
 	return 0;
 }
+
+/**
+ * Find PHY address
+ *
+ * @v mii		MII device
+ * @ret rc		Return status code
+ */
+int mii_find ( struct mii_device *mii ) {
+	unsigned int address;
+	int id;
+
+	/* Try all possible PHY addresses */
+	for ( address = 0 ; address <= MII_MAX_PHY_ADDRESS ; address++ ) {
+		mii->address = address;
+		id = mii_read ( mii, MII_PHYSID1 );
+		if ( ( id > 0x0000 ) && ( id < 0xffff ) ) {
+			DBGC ( mii, "MII %p found PHY at address %d\n",
+			       mii, address );
+			return 0;
+		}
+	}
+
+	DBGC ( mii, "MII %p failed to find an address\n", mii );
+	return -ENOENT;
+}

src/include/ipxe/mii.h

 /** Maximum time to wait for a reset, in milliseconds */
 #define MII_RESET_MAX_WAIT_MS 500
 
+/** Maximum PHY address */
+#define MII_MAX_PHY_ADDRESS 31
+
 extern int mii_restart ( struct mii_device *mii );
 extern int mii_reset ( struct mii_device *mii );
 extern int mii_check_link ( struct mii_device *mii,
 			    struct net_device *netdev );
+extern int mii_find ( struct mii_device *mii );
 
 #endif /* _IPXE_MII_H */