text: /*
   * Simulated Ethernet Driver
   *
   * Copyright (C) 1999-2001, 2003 Hewlett-Packard Co
   *	Stephane Eranian <eranian@hpl.hp.com>
   */
  #include <linux/kernel.h>
  #include <linux/sched.h>
  #include <linux/types.h>
  #include <linux/in.h>
  #include <linux/string.h>
  #include <linux/init.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/netdevice.h>
  #include <linux/etherdevice.h>
  #include <linux/inetdevice.h>
  #include <linux/if_ether.h>
  #include <linux/if_arp.h>
  #include <linux/skbuff.h>
  #include <linux/notifier.h>
  #include <linux/bitops.h>
  #include <asm/irq.h>
  #include <asm/hpsim.h>
  
  #include "hpsim_ssc.h"
  
  #define SIMETH_RECV_MAX	10
  
  /*
   * Maximum possible received frame for Ethernet.
   * We preallocate an sk_buff of that size to avoid costly
   * memcpy for temporary buffer into sk_buff. We do basically
   * what's done in other drivers, like eepro with a ring.
   * The difference is, of course, that we don't have real DMA !!!
   */
  #define SIMETH_FRAME_SIZE	ETH_FRAME_LEN
  
  
  #define NETWORK_INTR			8
  
  struct simeth_local {
  	struct net_device_stats stats;
  	int 			simfd;	 /* descriptor in the simulator */
  };
  
  static int simeth_probe1(void);
  static int simeth_open(struct net_device *dev);
  static int simeth_close(struct net_device *dev);
  static int simeth_tx(struct sk_buff *skb, struct net_device *dev);
  static int simeth_rx(struct net_device *dev);
  static struct net_device_stats *simeth_get_stats(struct net_device *dev);
  static irqreturn_t simeth_interrupt(int irq, void *dev_id);
  static void set_multicast_list(struct net_device *dev);
  static int simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr);
  
  static char *simeth_version="0.3";
  
  /*
   * This variable is used to establish a mapping between the Linux/ia64 kernel
   * and the host linux kernel.
   *
   * As of today, we support only one card, even though most of the code
   * is ready for many more. The mapping is then:
   *	linux/ia64 -> linux/x86
   * 	   eth0    -> eth1
   *
   * In the future, we some string operations, we could easily support up
   * to 10 cards (0-9).
   *
   * The default mapping can be changed on the kernel command line by
   * specifying simeth=ethX (or whatever string you want).
   */
  static char *simeth_device="eth0";	 /* default host interface to use */
  
  
  
  static volatile unsigned int card_count; /* how many cards "found" so far */
  static int simeth_debug;		/* set to 1 to get debug information */
  
  /*
   * Used to catch IFF_UP & IFF_DOWN events
   */
  static struct notifier_block simeth_dev_notifier = {
  	simeth_device_event,
  	NULL
  };
  
  
  /*
   * Function used when using a kernel command line option.
   *
   * Format: simeth=interface_name (like eth0)
   */
  static int __init
  simeth_setup(char *str)
  {
  	simeth_device = str;
  	return 1;
  }
  
  __setup("simeth=", simeth_setup);
  
  /*
   * Function used to probe for simeth devices when not installed
   * as a loadable module
   */
  
  int __init
  simeth_probe (void)
  {
  	int r;
  
  	printk(KERN_INFO "simeth: v%s\n", simeth_version);
  
  	r = simeth_probe1();
  
  	if (r == 0) register_netdevice_notifier(&simeth_dev_notifier);
  
  	return r;
  }
  
  static inline int
  netdev_probe(char *name, unsigned char *ether)
  {
  	return ia64_ssc(__pa(name), __pa(ether), 0,0, SSC_NETDEV_PROBE);
  }
  
  
  static inline int
  netdev_attach(int fd, int irq, unsigned int ipaddr)
  {
  	/* this puts the host interface in the right mode (start interrupting) */
  	return ia64_ssc(fd, ipaddr, 0,0, SSC_NETDEV_ATTACH);
  }
  
  
  static inline int
  netdev_detach(int fd)
  {
  	/*
  	 * inactivate the host interface (don't interrupt anymore) */
  	return ia64_ssc(fd, 0,0,0, SSC_NETDEV_DETACH);
  }
  
  static inline int
  netdev_send(int fd, unsigned char *buf, unsigned int len)
  {
  	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_SEND);
  }
  
  static inline int
  netdev_read(int fd, unsigned char *buf, unsigned int len)
  {
  	return ia64_ssc(fd, __pa(buf), len, 0, SSC_NETDEV_RECV);
  }
  
  static const struct net_device_ops simeth_netdev_ops = {
  	.ndo_open		= simeth_open,
  	.ndo_stop		= simeth_close,
  	.ndo_start_xmit		= simeth_tx,
  	.ndo_get_stats		= simeth_get_stats,
  	.ndo_set_rx_mode	= set_multicast_list, /* not yet used */
  
  };
  
  /*
   * Function shared with module code, so cannot be in init section
   *
   * So far this function "detects" only one card (test_&_set) but could
   * be extended easily.
   *
   * Return:
   * 	- -ENODEV is no device found
   *	- -ENOMEM is no more memory
   *	- 0 otherwise
   */
  static int
  simeth_probe1(void)
  {
  	unsigned char mac_addr[ETH_ALEN];
  	struct simeth_local *local;
  	struct net_device *dev;
  	int fd, err, rc;
  
  	/*
  	 * XXX Fix me
  	 * let's support just one card for now
  	 */
  	if (test_and_set_bit(0, &card_count))
  		return -ENODEV;
  
  	/*
  	 * check with the simulator for the device
  	 */
  	fd = netdev_probe(simeth_device, mac_addr);
  	if (fd == -1)
  		return -ENODEV;
  
  	dev = alloc_etherdev(sizeof(struct simeth_local));
  	if (!dev)
  		return -ENOMEM;
  
  	memcpy(dev->dev_addr, mac_addr, sizeof(mac_addr));
  
  	local = netdev_priv(dev);
  	local->simfd = fd; /* keep track of underlying file descriptor */
  
  	dev->netdev_ops = &simeth_netdev_ops;
  
  	err = register_netdev(dev);
  	if (err) {
  		free_netdev(dev);
  		return err;
  	}
  
  	/*
  	 * attach the interrupt in the simulator, this does enable interrupts
  	 * until a netdev_attach() is called
  	 */
  	if ((rc = hpsim_get_irq(NETWORK_INTR)) < 0)
  		panic("%s: out of interrupt vectors!\n", __func__);
  	dev->irq = rc;
  
  	printk(KERN_INFO "%s: hosteth=%s simfd=%d, HwAddr=%pm, IRQ %d\n",
  	       dev->name, simeth_device, local->simfd, dev->dev_addr, dev->irq);
  
  	return 0;
  }
  
  /*
   * actually binds the device to an interrupt vector
   */
  static int
  simeth_open(struct net_device *dev)
  {
  	if (request_irq(dev->irq, simeth_interrupt, 0, "simeth", dev)) {
  		printk(KERN_WARNING "simeth: unable to get IRQ %d.\n", dev->irq);
  		return -EAGAIN;
  	}
  
  	netif_start_queue(dev);
  
  	return 0;
  }
  
  /* copied from lapbether.c */
  static __inline__ int dev_is_ethdev(struct net_device *dev)
  {
         return ( dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5));
  }
  
  
  /*
   * Handler for IFF_UP or IFF_DOWN
   *
   * The reason for that is that we don't want to be interrupted when the
   * interface is down. There is no way to unconnect in the simualtor. Instead
   * we use this function to shutdown packet processing in the frame filter
   * in the simulator. Thus no interrupts are generated
   *
   *
   * That's also the place where we pass the IP address of this device to the
   * simulator so that that we can start filtering packets for it
   *
   * There may be a better way of doing this, but I don't know which yet.
   */
  static int
  simeth_device_event(struct notifier_block *this,unsigned long event, void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  	struct simeth_local *local;
  	struct in_device *in_dev;
  	struct in_ifaddr **ifap = NULL;
  	struct in_ifaddr *ifa = NULL;
  	int r;
  
  
  	if ( ! dev ) {
  		printk(KERN_WARNING "simeth_device_event dev=0\n");
  		return NOTIFY_DONE;
  	}
  
  	if (dev_net(dev) != &init_net)
  		return NOTIFY_DONE;
  
  	if ( event != NETDEV_UP && event != NETDEV_DOWN ) return NOTIFY_DONE;
  
  	/*
  	 * Check whether or not it's for an ethernet device
  	 *
  	 * XXX Fixme: This works only as long as we support one
  	 * type of ethernet device.
  	 */
  	if ( !dev_is_ethdev(dev) ) return NOTIFY_DONE;
  
  	if ((in_dev=dev->ip_ptr) != NULL) {
  		for (ifap=&in_dev->ifa_list; (ifa=*ifap) != NULL; ifap=&ifa->ifa_next)
  			if (strcmp(dev->name, ifa->ifa_label) == 0) break;
  	}
  	if ( ifa == NULL ) {
  		printk(KERN_ERR "simeth_open: can't find device %s's ifa\n", dev->name);
  		return NOTIFY_DONE;
  	}
  
  	printk(KERN_INFO "simeth_device_event: %s ipaddr=0x%x\n",
  	       dev->name, ntohl(ifa->ifa_local));
  
  	/*
  	 * XXX Fix me
  	 * if the device was up, and we're simply reconfiguring it, not sure
  	 * we get DOWN then UP.
  	 */
  
  	local = netdev_priv(dev);
  	/* now do it for real */
  	r = event == NETDEV_UP ?
  		netdev_attach(local->simfd, dev->irq, ntohl(ifa->ifa_local)):
  		netdev_detach(local->simfd);
  
  	printk(KERN_INFO "simeth: netdev_attach/detach: event=%s ->%d\n",
  	       event == NETDEV_UP ? "attach":"detach", r);
  
  	return NOTIFY_DONE;
  }
  
  static int
  simeth_close(struct net_device *dev)
  {
  	netif_stop_queue(dev);
  
  	free_irq(dev->irq, dev);
  
  	return 0;
  }
  
  /*
   * Only used for debug
   */
  static void
  frame_print(unsigned char *from, unsigned char *frame, int len)
  {
  	int i;
  
  	printk("%s: (%d) %02x", from, len, frame[0] & 0xff);
  	for(i=1; i < 6; i++ ) {
  		printk(":%02x", frame[i] &0xff);
  	}
  	printk(" %2x", frame[6] &0xff);
  	for(i=7; i < 12; i++ ) {
  		printk(":%02x", frame[i] &0xff);
  	}
  	printk(" [%02x%02x]\n", frame[12], frame[13]);
  
  	for(i=14; i < len; i++ ) {
  		printk("%02x ", frame[i] &0xff);
  		if ( (i%10)==0) printk("\n");
  	}
  	printk("\n");
  }
  
  
  /*
   * Function used to transmit of frame, very last one on the path before
   * going to the simulator.
   */
  static int
  simeth_tx(struct sk_buff *skb, struct net_device *dev)
  {
  	struct simeth_local *local = netdev_priv(dev);
  
  #if 0
  	/* ensure we have at least ETH_ZLEN bytes (min frame size) */
  	unsigned int length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
  	/* Where do the extra padding bytes comes from inthe skbuff ? */
  #else
  	/* the real driver in the host system is going to take care of that
  	 * or maybe it's the NIC itself.
  	 */
  	unsigned int length = skb->len;
  #endif
  
  	local->stats.tx_bytes += skb->len;
  	local->stats.tx_packets++;
  
  
  	if (simeth_debug > 5) frame_print("simeth_tx", skb->data, length);
  
  	netdev_send(local->simfd, skb->data, length);
  
  	/*
  	 * we are synchronous on write, so we don't simulate a
  	 * trasnmit complete interrupt, thus we don't need to arm a tx
  	 */
  
  	dev_kfree_skb(skb);
  	return NETDEV_TX_OK;
  }
  
  static inline struct sk_buff *
  make_new_skb(struct net_device *dev)
  {
  	struct sk_buff *nskb;
  
  	/*
  	 * The +2 is used to make sure that the IP header is nicely
  	 * aligned (on 4byte boundary I assume 14+2=16)
  	 */
  	nskb = dev_alloc_skb(SIMETH_FRAME_SIZE + 2);
  	if ( nskb == NULL ) {
  		printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
  		return NULL;
  	}
  
  	skb_reserve(nskb, 2);	/* Align IP on 16 byte boundaries */
  
  	skb_put(nskb,SIMETH_FRAME_SIZE);
  
  	return nskb;
  }
  
  /*
   * called from interrupt handler to process a received frame
   */
  static int
  simeth_rx(struct net_device *dev)
  {
  	struct simeth_local	*local;
  	struct sk_buff		*skb;
  	int			len;
  	int			rcv_count = SIMETH_RECV_MAX;
  
  	local = netdev_priv(dev);
  	/*
  	 * the loop concept has been borrowed from other drivers
  	 * looks to me like it's a throttling thing to avoid pushing to many
  	 * packets at one time into the stack. Making sure we can process them
  	 * upstream and make forward progress overall
  	 */
  	do {
  		if ( (skb=make_new_skb(dev)) == NULL ) {
  			printk(KERN_NOTICE "%s: memory squeeze. dropping packet.\n", dev->name);
  			local->stats.rx_dropped++;
  			return 0;
  		}
  		/*
  		 * Read only one frame at a time
  		 */
  		len = netdev_read(local->simfd, skb->data, SIMETH_FRAME_SIZE);
  		if ( len == 0 ) {
  			if ( simeth_debug > 0 ) printk(KERN_WARNING "%s: count=%d netdev_read=0\n",
  						       dev->name, SIMETH_RECV_MAX-rcv_count);
  			break;
  		}
  #if 0
  		/*
  		 * XXX Fix me
  		 * Should really do a csum+copy here
  		 */
  		skb_copy_to_linear_data(skb, frame, len);
  #endif
  		skb->protocol = eth_type_trans(skb, dev);
  
  		if ( simeth_debug > 6 ) frame_print("simeth_rx", skb->data, len);
  
  		/*
  		 * push the packet up & trigger software interrupt
  		 */
  		netif_rx(skb);
  
  		local->stats.rx_packets++;
  		local->stats.rx_bytes += len;
  
  	} while ( --rcv_count );
  
  	return len; /* 0 = nothing left to read, otherwise, we can try again */
  }
  
  /*
   * Interrupt handler (Yes, we can do it too !!!)
   */
  static irqreturn_t
  simeth_interrupt(int irq, void *dev_id)
  {
  	struct net_device *dev = dev_id;
  
  	/*
  	 * very simple loop because we get interrupts only when receiving
  	 */
  	while (simeth_rx(dev));
  	return IRQ_HANDLED;
  }
  
  static struct net_device_stats *
  simeth_get_stats(struct net_device *dev)
  {
  	struct simeth_local *local = netdev_priv(dev);
  
  	return &local->stats;
  }
  
  /* fake multicast ability */
  static void
  set_multicast_list(struct net_device *dev)
  {
  	printk(KERN_WARNING "%s: set_multicast_list called\n", dev->name);
  }
  
  __initcall(simeth_probe);
  