This adds a simple network driver for virtual
networking on the IBM Full System Simulator.

From: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>

Index: linux-2.6.16-rc/drivers/net/Makefile
===================================================================
--- linux-2.6.16-rc.orig/drivers/net/Makefile
+++ linux-2.6.16-rc/drivers/net/Makefile
@@ -145,6 +145,7 @@ obj-$(CONFIG_EL3) += 3c509.o
 obj-$(CONFIG_3C515) += 3c515.o
 obj-$(CONFIG_EEXPRESS) += eexpress.o
 obj-$(CONFIG_EEXPRESS_PRO) += eepro.o
+obj-$(CONFIG_SYSTEMSIM_NET) += systemsim_net.o
 obj-$(CONFIG_8139CP) += 8139cp.o
 obj-$(CONFIG_8139TOO) += 8139too.o
 obj-$(CONFIG_ZNET) += znet.o
Index: linux-2.6.16-rc/drivers/net/Kconfig
===================================================================
--- linux-2.6.16-rc.orig/drivers/net/Kconfig
+++ linux-2.6.16-rc/drivers/net/Kconfig
@@ -1175,6 +1175,14 @@ config IBMVETH
 	  <file:Documentation/networking/net-modules.txt>. The module will
 	  be called ibmveth.
 
+config SYSTEMSIM_NET
+	depends on PPC_SYSTEMSIM
+	tristate "    IBM Full System Simulator Bogus Network Support"
+	default y
+	help
+	  Provides quick access to a raw ethernet device in the simulator
+	  without simulating any specific network device hardware.
+
 config IBM_EMAC
 	tristate "PowerPC 4xx on-chip Ethernet support"
 	depends on 4xx
Index: linux-2.6.16-rc/drivers/net/systemsim_net.c
===================================================================
--- /dev/null
+++ linux-2.6.16-rc/drivers/net/systemsim_net.c
@@ -0,0 +1,392 @@
+/*
+ *  Bogus Network Driver for PowerPC Full System Simulator
+ *
+ *  (C) Copyright IBM Corporation 2003-2005
+ *
+ *  Bogus Network Driver
+ *
+ *  Author: JimiX <jimix@watson.ibm.com>
+ *  Maintained By: Eric Van Hensbergen <ericvh@gmail.com>
+ *
+ * 	inspired by drivers/net/ibmveth.c
+ *	written by Dave Larson
+ *
+ *  Some code is from the IBM Full System Simulator Group in ARL
+ *  Author: Patrick Bohrer <IBM Austin Research Lab>
+ *
+ *  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, or (at your option)
+ *  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:
+ *  Free Software Foundation
+ *  51 Franklin Street, Fifth Floor
+ *  Boston, MA  02111-1301  USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/interrupt.h>
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/in.h>
+#include <linux/init.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/if_ether.h>	/* For the statistics structure. */
+#include <linux/if_arp.h>	/* For ARPHRD_ETHER */
+#include <linux/workqueue.h>
+#include <asm/prom.h>
+#include <linux/version.h>
+#include <asm/systemsim.h>
+
+#define MAMBO_BOGUS_NET_PROBE   119
+#define MAMBO_BOGUS_NET_SEND    120
+#define MAMBO_BOGUS_NET_RECV    121
+
+static inline int MamboBogusNetProbe(int devno, void *buf)
+{
+	return callthru2(MAMBO_BOGUS_NET_PROBE,
+			 (unsigned long)devno, (unsigned long)buf);
+}
+
+static inline int MamboBogusNetSend(int devno, void *buf, ulong size)
+{
+	return callthru3(MAMBO_BOGUS_NET_SEND,
+			 (unsigned long)devno,
+			 (unsigned long)buf, (unsigned long)size);
+}
+
+static inline int MamboBogusNetRecv(int devno, void *buf, ulong size)
+{
+	return callthru3(MAMBO_BOGUS_NET_RECV,
+			 (unsigned long)devno,
+			 (unsigned long)buf, (unsigned long)size);
+}
+
+static irqreturn_t
+mambonet_interrupt(int irq, void *dev_instance, struct pt_regs *regs);
+
+#define INIT_BOTTOM_HALF(x,y,z) INIT_WORK(x, y, (void*)z)
+#define SCHEDULE_BOTTOM_HALF(x) schedule_delayed_work(x, 1)
+#define KILL_BOTTOM_HALF(x) cancel_delayed_work(x); flush_scheduled_work()
+
+#define MAMBO_MTU 1500
+
+struct netdev_private {
+	int devno;
+	int closing;
+	struct work_struct poll_task;
+	struct net_device_stats stats;
+};
+
+static int mambonet_probedev(int devno, void *buf)
+{
+	struct device_node *mambo;
+	struct device_node *net;
+	unsigned int *reg;
+
+	mambo = find_path_device("/mambo");
+
+	if (mambo == NULL) {
+		return -1;
+	}
+	net = find_path_device("/mambo/bogus-net@0");
+	if (net == NULL) {
+		return -1;
+	}
+	reg = (unsigned int *)get_property(net, "reg", 0);
+
+	if (*reg != devno) {
+		return -1;
+	}
+
+	return MamboBogusNetProbe(devno, buf);
+}
+
+static int mambonet_send(int devno, void *buf, ulong size)
+{
+	return MamboBogusNetSend(devno, buf, size);
+}
+
+static int mambonet_recv(int devno, void *buf, ulong size)
+{
+	return MamboBogusNetRecv(devno, buf, size);
+}
+
+static int mambonet_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct netdev_private *priv = (struct netdev_private *)dev->priv;
+	int devno = priv->devno;
+
+	skb->dev = dev;
+
+	/* we might need to checksum or something */
+	mambonet_send(devno, skb->data, skb->len);
+
+	dev->last_rx = jiffies;
+	priv->stats.rx_bytes += skb->len;
+	priv->stats.tx_bytes += skb->len;
+	priv->stats.rx_packets++;
+	priv->stats.tx_packets++;
+
+	dev_kfree_skb(skb);
+
+	return (0);
+}
+
+static int mambonet_poll(struct net_device *dev, int *budget)
+{
+	struct netdev_private *np = dev->priv;
+	int devno = np->devno;
+	char buffer[1600];
+	int ns;
+	struct sk_buff *skb;
+	int frames = 0;
+	int max_frames = min(*budget, dev->quota);
+	int ret = 0;
+
+	while ((ns = mambonet_recv(devno, buffer, 1600)) > 0) {
+		if ((skb = dev_alloc_skb(ns + 2)) != NULL) {
+			skb->dev = dev;
+			skb_reserve(skb, 2);	/* 16 byte align the IP
+						 * header */
+#ifdef HAS_IP_COPYSUM
+			eth_copy_and_sum(skb, buffer, ns, 0);
+			skb_put(skb, ns);
+#else
+			memcpy(skb_put(skb, ns), buffer, ns);
+#endif
+			skb->protocol = eth_type_trans(skb, dev);
+
+			if (dev->irq)
+				netif_receive_skb(skb);
+			else
+				netif_rx(skb);
+
+			dev->last_rx = jiffies;
+			np->stats.rx_packets++;
+			np->stats.rx_bytes += ns;
+		} else {
+			printk("Failed to allocated skbuff, "
+			       "dropping packet\n");
+			np->stats.rx_dropped++;
+			/* wait for another cycle */
+			return 1;
+		}
+		++frames;
+		if (frames > max_frames) {
+			ret = 1;
+			break;
+		}
+	}
+	*budget -= frames;
+	dev->quota -= frames;
+
+	if ((!ret) && (dev->irq))
+		netif_rx_complete(dev);
+
+	return ret;
+}
+
+static void mambonet_timer(struct net_device *dev)
+{
+	int budget = 16;
+	struct netdev_private *priv = (struct netdev_private *)dev->priv;
+
+	mambonet_poll(dev, &budget);
+
+	if (!priv->closing) {
+		SCHEDULE_BOTTOM_HALF(&priv->poll_task);
+	}
+}
+
+static struct net_device_stats *get_stats(struct net_device *dev)
+{
+	struct netdev_private *priv = (struct netdev_private *)dev->priv;
+	return (struct net_device_stats *)&(priv->stats);
+}
+
+static irqreturn_t
+mambonet_interrupt(int irq, void *dev_instance, struct pt_regs *regs)
+{
+	struct net_device *dev = dev_instance;
+	if (netif_rx_schedule_prep(dev)) {
+		__netif_rx_schedule(dev);
+	}
+	return IRQ_HANDLED;
+}
+
+static int mambonet_open(struct net_device *dev)
+{
+	struct netdev_private *priv;
+	int ret = 0;
+
+	priv = dev->priv;
+
+	/*
+	 * we can't start polling in mambonet_init, because I don't think
+	 * workqueues are usable that early. so start polling now.
+	 */
+
+	if (dev->irq) {
+		ret = request_irq(dev->irq, &mambonet_interrupt, 0,
+				  dev->name, dev);
+
+		if (ret == 0) {
+			netif_start_queue(dev);
+		} else {
+			printk(KERN_ERR "mambonet: request irq failed\n");
+		}
+
+		MamboBogusNetProbe(priv->devno, NULL);	/* probe with NULL to activate interrupts */
+	} else {
+		mambonet_timer(dev);
+	}
+
+	return ret;
+}
+
+static int mambonet_close(struct net_device *dev)
+{
+	struct netdev_private *priv;
+
+	netif_stop_queue(dev);
+
+	if (dev->irq)
+		free_irq(dev->irq, dev);
+
+	priv = dev->priv;
+	priv->closing = 1;
+	if (dev->irq == 0) {
+		KILL_BOTTOM_HALF(&priv->poll_task);
+	}
+
+	kfree(priv);
+
+	return 0;
+}
+
+static struct net_device_stats mambonet_stats;
+
+static struct net_device_stats *mambonet_get_stats(struct net_device *dev)
+{
+	return &mambonet_stats;
+}
+
+static int mambonet_set_mac_address(struct net_device *dev, void *p)
+{
+	return -EOPNOTSUPP;
+}
+static int mambonet_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	return -EOPNOTSUPP;
+}
+static int nextdevno = 0;	/* running count of device numbers */
+
+/* Initialize the rest of the device. */
+int __init do_mambonet_probe(struct net_device *dev)
+{
+	struct netdev_private *priv;
+	int devno = nextdevno++;
+	int irq;
+
+	printk("eth%d: bogus network driver initialization\n", devno);
+
+	irq = mambonet_probedev(devno, dev->dev_addr);
+
+	if (irq < 0) {
+		printk("No IRQ retreived\n");
+		return (-ENODEV);
+	}
+
+	printk("%s: %2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n", dev->name,
+	       dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
+	       dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
+
+	SET_MODULE_OWNER(dev);
+
+	dev->irq = irq;
+	dev->mtu = MAMBO_MTU;
+	dev->open = mambonet_open;
+	dev->poll = mambonet_poll;
+	dev->weight = 16;
+	dev->stop = mambonet_close;
+	dev->hard_start_xmit = mambonet_start_xmit;
+	dev->get_stats = mambonet_get_stats;
+	dev->set_mac_address = mambonet_set_mac_address;
+	dev->do_ioctl = mambonet_ioctl;
+
+	dev->priv = kmalloc(sizeof(struct netdev_private), GFP_KERNEL);
+	if (dev->priv == NULL)
+		return -ENOMEM;
+	memset(dev->priv, 0, sizeof(struct netdev_private));
+
+	priv = dev->priv;
+	priv->devno = devno;
+	priv->closing = 0;
+	dev->get_stats = get_stats;
+
+	if (dev->irq == 0) {
+		INIT_BOTTOM_HALF(&priv->poll_task, (void *)mambonet_timer,
+				 (void *)dev);
+	}
+
+	return (0);
+};
+
+struct net_device *__init mambonet_probe(int unit)
+{
+	struct net_device *dev = alloc_etherdev(0);
+	int err;
+
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	sprintf(dev->name, "eth%d", unit);
+	netdev_boot_setup_check(dev);
+
+	err = do_mambonet_probe(dev);
+
+	if (err)
+		goto out;
+
+	err = register_netdev(dev);
+	if (err)
+		goto out;
+
+	return dev;
+
+      out:
+	free_netdev(dev);
+	return ERR_PTR(err);
+}
+
+int __init init_mambonet(void)
+{
+	mambonet_probe(0);
+	return 0;
+}
+
+module_init(init_mambonet);
+MODULE_LICENSE("GPL");

--