Kill off hotplug.h and just make net devices normal reference-counted

structures.

DHCP still broken and #if 0'd out.

src/include/gpxe/aoe.h

@@ -13,7 +13,6 @@
 #include <gpxe/retry.h>
 #include <gpxe/async.h>
 #include <gpxe/ata.h>
-#include <gpxe/hotplug.h>
 
 /** An AoE ATA command */
 struct aoecmd {
@@ -87,8 +86,6 @@ struct aoe_session {
 
 	/** Network device */
 	struct net_device *netdev;
-	/** Reference to network device */
-	struct reference netdev_ref;
 
 	/** Major number */
 	uint16_t major;

src/include/gpxe/dhcp.h

@@ -13,7 +13,6 @@
 #include <gpxe/udp.h>
 #include <gpxe/async.h>
 #include <gpxe/retry.h>
-#include <gpxe/hotplug.h>
 
 /** BOOTP/DHCP server port */
 #define BOOTPS_PORT 67
@@ -449,6 +448,8 @@ struct dhcp_packet {
 	struct dhcp_option_block options[NUM_OPT_BLOCKS];
 };
 
+struct udp_connection {};
+
 /** A DHCP session */
 struct dhcp_session {
 	/** UDP connection for this session */
@@ -456,8 +457,6 @@ struct dhcp_session {
 
 	/** Network device being configured */
 	struct net_device *netdev;
-	/** Persistent reference to network device */
-	struct reference netdev_ref;
 
 	/** Options obtained from server */
 	struct dhcp_option_block *options;

src/include/gpxe/hotplug.h

@@ -1,58 +0,0 @@
-#ifndef _GPXE_HOTPLUG_H
-#define _GPXE_HOTPLUG_H
-
-/** @file
- *
- * Hotplug support
- *
- */
-
-#include <gpxe/list.h>
-
-/**
- * A persistent reference to another data structure
- *
- * This data structure should be embedded within any data structure
- * (the referrer) which holds a persistent reference to a separate,
- * volatile data structure (the referee).
- */
-struct reference {
-	/** List of persistent references */
-	struct list_head list;
-	/** Forget persistent reference
-	 *
-	 * @v ref		Persistent reference
-	 *
-	 * This method is called immediately before the referred-to
-	 * data structure is destroyed.  The reference holder must
-	 * forget all references to the referee before returning from
-	 * this method.
-	 *
-	 * This method must also call ref_del() to remove the
-	 * reference.
-	 */
-	void ( * forget ) ( struct reference *ref );
-};
-
-/**
- * Add persistent reference
- *
- * @v ref		Persistent reference
- * @v list		List of persistent references
- */
-static inline void ref_add ( struct reference *ref, struct list_head *list ) {
-	list_add ( &ref->list, list );
-}
-
-/**
- * Remove persistent reference
- *
- * @v ref		Persistent reference
- */
-static inline void ref_del ( struct reference *ref ) {
-	list_del ( &ref->list );
-}
-
-extern void forget_references ( struct list_head *list );
-
-#endif /* _GPXE_HOTPLUG_H */

src/include/gpxe/ip.h

@@ -9,7 +9,6 @@
 
 #include <ip.h>
 #include <gpxe/retry.h>
-#include <gpxe/hotplug.h>
 
 /* IP constants */
 
@@ -44,8 +43,6 @@ struct ipv4_miniroute {
 
 	/** Network device */
 	struct net_device *netdev;
-	/** Reference to network device */
-	struct reference netdev_ref;
 
 	/** IPv4 address */
 	struct in_addr address;

src/include/gpxe/netdevice.h

@@ -10,7 +10,7 @@
 #include <stdint.h>
 #include <gpxe/list.h>
 #include <gpxe/tables.h>
-#include <gpxe/hotplug.h>
+#include <gpxe/refcnt.h>
 
 struct io_buffer;
 struct net_device;
@@ -137,14 +137,14 @@ struct ll_protocol {
  * not just an Ethernet device.
  */
 struct net_device {
+	/** Reference counter */
+	struct refcnt refcnt;
 	/** List of network devices */
 	struct list_head list;
 	/** Name of this network device */
 	char name[8];
 	/** Underlying hardware device */
 	struct device *dev;
-	/** List of persistent reference holders */
-	struct list_head references;
 
 	/** Open network device
 	 *
@@ -251,6 +251,28 @@ static inline int have_netdevs ( void ) {
 	return ( ! list_empty ( &net_devices ) );
 }
 
+/**
+ * Get reference to network device
+ *
+ * @v netdev		Network device
+ * @ret netdev		Network device
+ */
+static inline __attribute__ (( always_inline )) struct net_device *
+netdev_get ( struct net_device *netdev ) {
+	ref_get ( &netdev->refcnt );
+	return netdev;
+}
+
+/**
+ * Drop reference to network device
+ *
+ * @v netdev		Network device
+ */
+static inline __attribute__ (( always_inline )) void
+netdev_put ( struct net_device *netdev ) {
+	ref_put ( &netdev->refcnt );
+}
+
 extern int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf );
 void netdev_tx_complete ( struct net_device *netdev, struct io_buffer *iobuf );
 void netdev_tx_complete_next ( struct net_device *netdev );
@@ -262,7 +284,6 @@ extern int register_netdev ( struct net_device *netdev );
 extern int netdev_open ( struct net_device *netdev );
 extern void netdev_close ( struct net_device *netdev );
 extern void unregister_netdev ( struct net_device *netdev );
-extern void free_netdev ( struct net_device *netdev );
 struct net_device * find_netdev ( const char *name );
 struct net_device * find_pci_netdev ( unsigned int busdevfn );