diff --git a/drivers/net/cs8900.c b/drivers/net/cs8900.c
index da23755..291fd0a 100644
--- a/drivers/net/cs8900.c
+++ b/drivers/net/cs8900.c
@@ -360,7 +360,7 @@
 
 static void cs8900_info(struct device_d *dev)
 {
-	struct eth_device *edev = (struct eth_device *)dev->type_data;
+	struct eth_device *edev = dev_to_edev(dev);
 	struct cs8900_priv *priv = (struct cs8900_priv *)edev->priv;
 	u16 v;
 
diff --git a/include/net.h b/include/net.h
index 1026793..2eec47f 100644
--- a/include/net.h
+++ b/include/net.h
@@ -48,6 +48,8 @@
 	struct list_head list;
 };
 
+#define dev_to_edev(d) container_of(d, struct eth_device, dev)
+
 int eth_register(struct eth_device* dev);    /* Register network device		*/
 void eth_unregister(struct eth_device* dev); /* Unregister network device	*/
 
diff --git a/net/eth.c b/net/eth.c
index 20fdbf4..00b8836 100644
--- a/net/eth.c
+++ b/net/eth.c
@@ -147,7 +147,7 @@
 
 static int eth_set_ethaddr(struct device_d *dev, struct param_d *param, const char *val)
 {
-	struct eth_device *edev = dev->type_data;
+	struct eth_device *edev = dev_to_edev(dev);
 	char ethaddr[sizeof("xx:xx:xx:xx:xx:xx")];
 
 	if (!val)
@@ -168,7 +168,7 @@
 
 static int eth_set_ipaddr(struct device_d *dev, struct param_d *param, const char *val)
 {
-	struct eth_device *edev = dev->type_data;
+	struct eth_device *edev = dev_to_edev(dev);
 	IPaddr_t ip;
 
 	if (!val)
@@ -205,7 +205,6 @@
 
 	register_device(&edev->dev);
 
-	dev->type_data = edev;
 	dev_add_param(dev, "ipaddr", eth_set_ipaddr, NULL, 0);
 	dev_add_param(dev, "ethaddr", eth_set_ethaddr, NULL, 0);
 	dev_add_param(dev, "gateway", eth_set_ipaddr, NULL, 0);