Use net_device_operations structure and netdev_nullify() to allow for

safe dropping of the netdev ref by the driver while other refs still
exist.

Add netdev_irq() method.  Net device open()/close() methods should no
longer enable or disable IRQs.

Remove rx_quota; it wasn't used anywhere and added too much complexity
to implementing correct interrupt-masking behaviour in pxe_undi.c.

2 files changed, 76 insertions, 14 deletions

diff --git a/src/net/netdevice.c b/src/net/netdevice.c
index d72392ca0..460de89cf 100644
--- a/src/net/netdevice.c
+++ b/src/net/netdevice.c
@@ -68,7 +68,7 @@ int netdev_tx ( struct net_device *netdev, struct io_buffer *iobuf ) {
 		goto err;
 	}
 		
-	if ( ( rc = netdev->transmit ( netdev, iobuf ) ) != 0 )
+	if ( ( rc = netdev->op->transmit ( netdev, iobuf ) ) != 0 )
 		goto err;
 
 	return 0;
@@ -187,22 +187,18 @@ void netdev_rx_err ( struct net_device *netdev,
 }
 
 /**
- * Poll for packet on network device
+ * Poll for completed and received packets on network device
  *
  * @v netdev		Network device
- * @v rx_quota		Maximum number of packets to receive
- * @ret True		There are packets present in the receive queue
- * @ret False		There are no packets present in the receive queue
  *
- * Polls the network device for received packets.  Any received
- * packets will be added to the RX packet queue via netdev_rx().
+ * Polls the network device for completed transmissions and received
+ * packets.  Any received packets will be added to the RX packet queue
+ * via netdev_rx().
  */
-int netdev_poll ( struct net_device *netdev, unsigned int rx_quota ) {
+void netdev_poll ( struct net_device *netdev ) {
 
 	if ( netdev->state & NETDEV_OPEN )
-		netdev->poll ( netdev, rx_quota );
-
-	return ( ! list_empty ( &netdev->rx_queue ) );
+		netdev->op->poll ( netdev );
 }
 
 /**
@@ -317,7 +313,7 @@ int netdev_open ( struct net_device *netdev ) {
 	DBGC ( netdev, "NETDEV %p opening\n", netdev );
 
 	/* Open the device */
-	if ( ( rc = netdev->open ( netdev ) ) != 0 )
+	if ( ( rc = netdev->op->open ( netdev ) ) != 0 )
 		return rc;
 
 	/* Mark as opened */
@@ -339,7 +335,7 @@ void netdev_close ( struct net_device *netdev ) {
 	DBGC ( netdev, "NETDEV %p closing\n", netdev );
 
 	/* Close the device */
-	netdev->close ( netdev );
+	netdev->op->close ( netdev );
 
 	/* Flush TX and RX queues */
 	netdev_tx_flush ( netdev );
@@ -367,6 +363,15 @@ void unregister_netdev ( struct net_device *netdev ) {
 	DBGC ( netdev, "NETDEV %p unregistered\n", netdev );
 }
 
+/** Enable or disable interrupts
+ *
+ * @v netdev		Network device
+ * @v enable		Interrupts should be enabled
+ */
+void netdev_irq ( struct net_device *netdev, int enable ) {
+	netdev->op->irq ( netdev, enable );
+}
+
 /**
  * Get network device by name
  *
@@ -462,7 +467,7 @@ static void net_step ( struct process *process __unused ) {
 	list_for_each_entry ( netdev, &net_devices, list ) {
 
 		/* Poll for new packets */
-		netdev_poll ( netdev, -1U );
+		netdev_poll ( netdev );
 
 		/* Process at most one received packet.  Give priority
 		 * to getting packets out of the NIC over processing
diff --git a/src/net/nullnet.c b/src/net/nullnet.c
new file mode 100644
index 000000000..4b6ba4c16
--- /dev/null
+++ b/src/net/nullnet.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdint.h>
+#include <gpxe/iobuf.h>
+#include <gpxe/netdevice.h>
+
+/** @file
+ *
+ * Null network device
+ *
+ */
+
+static int null_open ( struct net_device *netdev __unused ) {
+	return -ENODEV;
+};
+
+static void null_close ( struct net_device *netdev __unused ) {
+	/* Do nothing */
+};
+
+static int null_transmit ( struct net_device *netdev __unused,
+			   struct io_buffer *iobuf __unused ) {
+	return -ENODEV;
+};
+
+static void null_poll ( struct net_device *netdev __unused ) {
+	/* Do nothing */
+}
+
+static void null_irq ( struct net_device *netdev __unused,
+		       int enable __unused ) {
+	/* Do nothing */
+}
+
+struct net_device_operations null_netdev_operations = {
+	.open		= null_open,
+	.close		= null_close,
+	.transmit	= null_transmit,
+	.poll		= null_poll,
+	.irq   		= null_irq,
+};