/*
   * Linux ARCnet driver - device-independent routines

   *

   * Written 1997 by David Woodhouse.
   * Written 1994-1999 by Avery Pennarun.
   * Written 1999-2000 by Martin Mares <mj@ucw.cz>.
   * Derived from skeleton.c by Donald Becker.
   *
   * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
   *  for sponsoring the further development of this driver.
   *
   * **********************
   *
   * The original copyright was as follows:
   *
   * skeleton.c Written 1993 by Donald Becker.
   * Copyright 1993 United States Government as represented by the
   * Director, National Security Agency.  This software may only be used
   * and distributed according to the terms of the GNU General Public License as
   * modified by SRC, incorporated herein by reference.
   *
   * **********************

   *

   * The change log is now in a file called ChangeLog in this directory.
   *
   * Sources:
   *  - Crynwr arcnet.com/arcether.com packet drivers.

   *  - arcnet.c v0.00 dated 1/1/94 and apparently by

   *     Donald Becker - it didn't work :)
   *  - skeleton.c v0.05 dated 11/16/93 by Donald Becker
   *     (from Linux Kernel 1.1.45)
   *  - RFC's 1201 and 1051 - re: TCP/IP over ARCnet
   *  - The official ARCnet COM9026 data sheets (!) thanks to
   *     Ken Cornetet <kcornete@nyx10.cs.du.edu>
   *  - The official ARCnet COM20020 data sheets.
   *  - Information on some more obscure ARCnet controller chips, thanks
   *     to the nice people at SMSC.
   *  - net/inet/eth.c (from kernel 1.1.50) for header-building info.
   *  - Alternate Linux ARCnet source by V.Shergin <vsher@sao.stavropol.su>
   *  - Textual information and more alternate source from Joachim Koenig
   *     <jojo@repas.de>
   */

  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

  
  #include <linux/module.h>

  #include <linux/types.h>
  #include <linux/delay.h>
  #include <linux/netdevice.h>
  #include <linux/if_arp.h>
  #include <net/arp.h>
  #include <linux/init.h>

  #include <linux/jiffies.h>

  #include <linux/errqueue.h>

  #include <linux/leds.h>

  #include "arcdevice.h"

  #include "com9026.h"

  /* "do nothing" functions for protocol drivers */
  static void null_rx(struct net_device *dev, int bufnum,
  		    struct archdr *pkthdr, int length);
  static int null_build_header(struct sk_buff *skb, struct net_device *dev,
  			     unsigned short type, uint8_t daddr);
  static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
  			   int length, int bufnum);

  static void arcnet_rx(struct net_device *dev, int bufnum);

  /* one ArcProto per possible proto ID.  None of the elements of

   * arc_proto_map are allowed to be NULL; they will get set to
   * arc_proto_default instead.  It also must not be NULL; if you would like
   * to set it to NULL, set it to &arc_proto_null instead.
   */

  struct ArcProto *arc_proto_map[256];
  EXPORT_SYMBOL(arc_proto_map);
  
  struct ArcProto *arc_proto_default;
  EXPORT_SYMBOL(arc_proto_default);
  
  struct ArcProto *arc_bcast_proto;
  EXPORT_SYMBOL(arc_bcast_proto);
  
  struct ArcProto *arc_raw_proto;
  EXPORT_SYMBOL(arc_raw_proto);

  static struct ArcProto arc_proto_null = {

  	.suffix		= '?',
  	.mtu		= XMTU,
  	.is_ip          = 0,
  	.rx		= null_rx,
  	.build_header	= null_build_header,
  	.prepare_tx	= null_prepare_tx,
  	.continue_tx    = NULL,
  	.ack_tx         = NULL
  };
  
  /* Exported function prototypes */
  int arcnet_debug = ARCNET_DEBUG;

  EXPORT_SYMBOL(arcnet_debug);

  
  /* Internal function prototypes */

  static int arcnet_header(struct sk_buff *skb, struct net_device *dev,

  			 unsigned short type, const void *daddr,
  			 const void *saddr, unsigned len);

  static int go_tx(struct net_device *dev);
  
  static int debug = ARCNET_DEBUG;
  module_param(debug, int, 0);
  MODULE_LICENSE("GPL");
  
  static int __init arcnet_init(void)
  {
  	int count;
  
  	arcnet_debug = debug;

  	pr_info("arcnet loaded
  ");

  
  	/* initialize the protocol map */
  	arc_raw_proto = arc_proto_default = arc_bcast_proto = &arc_proto_null;
  	for (count = 0; count < 256; count++)
  		arc_proto_map[count] = arc_proto_default;

  	if (BUGLVL(D_DURING))

  		pr_info("struct sizes: %zd %zd %zd %zd %zd
  ",

  			sizeof(struct arc_hardware),
  			sizeof(struct arc_rfc1201),
  			sizeof(struct arc_rfc1051),
  			sizeof(struct arc_eth_encap),
  			sizeof(struct archdr));

  
  	return 0;
  }
  
  static void __exit arcnet_exit(void)
  {
  }
  
  module_init(arcnet_init);
  module_exit(arcnet_exit);

  /* Dump the contents of an sk_buff */

  #if ARCNET_DEBUG_MAX & D_SKB
  void arcnet_dump_skb(struct net_device *dev,
  		     struct sk_buff *skb, char *desc)
  {

  	char hdr[32];

  	/* dump the packet */
  	snprintf(hdr, sizeof(hdr), "%6s:%s skb->data:", dev->name, desc);
  	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
  		       16, 1, skb->data, skb->len, true);

  }

  EXPORT_SYMBOL(arcnet_dump_skb);
  #endif

  /* Dump the contents of an ARCnet buffer */

  #if (ARCNET_DEBUG_MAX & (D_RX | D_TX))

  static void arcnet_dump_packet(struct net_device *dev, int bufnum,
  			       char *desc, int take_arcnet_lock)

  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	int i, length;
  	unsigned long flags = 0;
  	static uint8_t buf[512];

  	char hdr[32];

  
  	/* hw.copy_from_card expects IRQ context so take the IRQ lock

  	 * to keep it single threaded
  	 */

  	if (take_arcnet_lock)

  		spin_lock_irqsave(&lp->lock, flags);
  
  	lp->hw.copy_from_card(dev, bufnum, 0, buf, 512);

  	if (take_arcnet_lock)

  		spin_unlock_irqrestore(&lp->lock, flags);
  
  	/* if the offset[0] byte is nonzero, this is a 256-byte packet */
  	length = (buf[2] ? 256 : 512);

  	/* dump the packet */
  	snprintf(hdr, sizeof(hdr), "%6s:%s packet dump:", dev->name, desc);
  	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
  		       16, 1, buf, length, true);

  }

  #else

  #define arcnet_dump_packet(dev, bufnum, desc, take_arcnet_lock) do { } while (0)

  #endif

  /* Trigger a LED event in response to a ARCNET device event */
  void arcnet_led_event(struct net_device *dev, enum arcnet_led_event event)
  {
  	struct arcnet_local *lp = netdev_priv(dev);
  	unsigned long led_delay = 350;
  	unsigned long tx_delay = 50;
  
  	switch (event) {
  	case ARCNET_LED_EVENT_RECON:
  		led_trigger_blink_oneshot(lp->recon_led_trig,
  					  &led_delay, &led_delay, 0);
  		break;
  	case ARCNET_LED_EVENT_OPEN:
  		led_trigger_event(lp->tx_led_trig, LED_OFF);
  		led_trigger_event(lp->recon_led_trig, LED_OFF);
  		break;
  	case ARCNET_LED_EVENT_STOP:
  		led_trigger_event(lp->tx_led_trig, LED_OFF);
  		led_trigger_event(lp->recon_led_trig, LED_OFF);
  		break;
  	case ARCNET_LED_EVENT_TX:
  		led_trigger_blink_oneshot(lp->tx_led_trig,
  					  &tx_delay, &tx_delay, 0);
  		break;
  	}
  }
  EXPORT_SYMBOL_GPL(arcnet_led_event);
  
  static void arcnet_led_release(struct device *gendev, void *res)
  {
  	struct arcnet_local *lp = netdev_priv(to_net_dev(gendev));
  
  	led_trigger_unregister_simple(lp->tx_led_trig);
  	led_trigger_unregister_simple(lp->recon_led_trig);
  }
  
  /* Register ARCNET LED triggers for a arcnet device
   *
   * This is normally called from a driver's probe function
   */
  void devm_arcnet_led_init(struct net_device *netdev, int index, int subid)
  {
  	struct arcnet_local *lp = netdev_priv(netdev);
  	void *res;
  
  	res = devres_alloc(arcnet_led_release, 0, GFP_KERNEL);
  	if (!res) {
  		netdev_err(netdev, "cannot register LED triggers
  ");
  		return;
  	}
  
  	snprintf(lp->tx_led_trig_name, sizeof(lp->tx_led_trig_name),
  		 "arc%d-%d-tx", index, subid);
  	snprintf(lp->recon_led_trig_name, sizeof(lp->recon_led_trig_name),
  		 "arc%d-%d-recon", index, subid);
  
  	led_trigger_register_simple(lp->tx_led_trig_name,
  				    &lp->tx_led_trig);
  	led_trigger_register_simple(lp->recon_led_trig_name,
  				    &lp->recon_led_trig);
  
  	devres_add(&netdev->dev, res);
  }
  EXPORT_SYMBOL_GPL(devm_arcnet_led_init);

  /* Unregister a protocol driver from the arc_proto_map.  Protocol drivers

   * are responsible for registering themselves, but the unregister routine
   * is pretty generic so we'll do it here.
   */
  void arcnet_unregister_proto(struct ArcProto *proto)
  {
  	int count;
  
  	if (arc_proto_default == proto)
  		arc_proto_default = &arc_proto_null;
  	if (arc_bcast_proto == proto)
  		arc_bcast_proto = arc_proto_default;
  	if (arc_raw_proto == proto)
  		arc_raw_proto = arc_proto_default;
  
  	for (count = 0; count < 256; count++) {
  		if (arc_proto_map[count] == proto)
  			arc_proto_map[count] = arc_proto_default;
  	}
  }

  EXPORT_SYMBOL(arcnet_unregister_proto);

  /* Add a buffer to the queue.  Only the interrupt handler is allowed to do

   * this, unless interrupts are disabled.

   *

   * Note: we don't check for a full queue, since there aren't enough buffers
   * to more than fill it.
   */
  static void release_arcbuf(struct net_device *dev, int bufnum)
  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	int i;
  
  	lp->buf_queue[lp->first_free_buf++] = bufnum;
  	lp->first_free_buf %= 5;

  	if (BUGLVL(D_DURING)) {

  		arc_printk(D_DURING, dev, "release_arcbuf: freed #%d; buffer queue is now: ",
  			   bufnum);

  		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)

  			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
  		arc_cont(D_DURING, "
  ");

  	}
  }

  /* Get a buffer from the queue.
   * If this returns -1, there are no buffers available.

   */
  static int get_arcbuf(struct net_device *dev)
  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	int buf = -1, i;
  
  	if (!atomic_dec_and_test(&lp->buf_lock)) {
  		/* already in this function */

  		arc_printk(D_NORMAL, dev, "get_arcbuf: overlap (%d)!
  ",
  			   lp->buf_lock.counter);

  	} else {			/* we can continue */

  		if (lp->next_buf >= 5)
  			lp->next_buf -= 5;

  		if (lp->next_buf == lp->first_free_buf) {

  			arc_printk(D_NORMAL, dev, "get_arcbuf: BUG: no buffers are available??
  ");

  		} else {

  			buf = lp->buf_queue[lp->next_buf++];
  			lp->next_buf %= 5;
  		}
  	}

  	if (BUGLVL(D_DURING)) {

  		arc_printk(D_DURING, dev, "get_arcbuf: got #%d; buffer queue is now: ",
  			   buf);

  		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)

  			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
  		arc_cont(D_DURING, "
  ");

  	}
  
  	atomic_inc(&lp->buf_lock);
  	return buf;
  }

  static int choose_mtu(void)
  {
  	int count, mtu = 65535;
  
  	/* choose the smallest MTU of all available encaps */
  	for (count = 0; count < 256; count++) {

  		if (arc_proto_map[count] != &arc_proto_null &&
  		    arc_proto_map[count]->mtu < mtu) {

  			mtu = arc_proto_map[count]->mtu;
  		}
  	}
  
  	return mtu == 65535 ? XMTU : mtu;
  }

  static const struct header_ops arcnet_header_ops = {
  	.create = arcnet_header,

  };

  static const struct net_device_ops arcnet_netdev_ops = {
  	.ndo_open	= arcnet_open,
  	.ndo_stop	= arcnet_close,
  	.ndo_start_xmit = arcnet_send_packet,
  	.ndo_tx_timeout = arcnet_timeout,
  };

  
  /* Setup a struct device for ARCnet. */
  static void arcdev_setup(struct net_device *dev)
  {
  	dev->type = ARPHRD_ARCNET;

  	dev->netdev_ops = &arcnet_netdev_ops;

  	dev->header_ops = &arcnet_header_ops;

  	dev->hard_header_len = sizeof(struct arc_hardware);

  	dev->mtu = choose_mtu();
  
  	dev->addr_len = ARCNET_ALEN;
  	dev->tx_queue_len = 100;
  	dev->broadcast[0] = 0x00;	/* for us, broadcasts are address 0 */
  	dev->watchdog_timeo = TX_TIMEOUT;
  
  	/* New-style flags. */
  	dev->flags = IFF_BROADCAST;

  }

  static void arcnet_timer(struct timer_list *t)

  {

  	struct arcnet_local *lp = from_timer(lp, t, timer);
  	struct net_device *dev = lp->dev;

  
  	if (!netif_carrier_ok(dev)) {
  		netif_carrier_on(dev);
  		netdev_info(dev, "link up
  ");
  	}
  }

  static void arcnet_reply_tasklet(unsigned long data)
  {
  	struct arcnet_local *lp = (struct arcnet_local *)data;
  
  	struct sk_buff *ackskb, *skb;
  	struct sock_exterr_skb *serr;
  	struct sock *sk;
  	int ret;
  
  	local_irq_disable();
  	skb = lp->outgoing.skb;
  	if (!skb || !skb->sk) {
  		local_irq_enable();
  		return;
  	}
  
  	sock_hold(skb->sk);
  	sk = skb->sk;
  	ackskb = skb_clone_sk(skb);
  	sock_put(skb->sk);
  
  	if (!ackskb) {
  		local_irq_enable();
  		return;
  	}
  
  	serr = SKB_EXT_ERR(ackskb);
  	memset(serr, 0, sizeof(*serr));
  	serr->ee.ee_errno = ENOMSG;
  	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
  	serr->ee.ee_data = skb_shinfo(skb)->tskey;
  	serr->ee.ee_info = lp->reply_status;
  
  	/* finally erasing outgoing skb */
  	dev_kfree_skb(lp->outgoing.skb);
  	lp->outgoing.skb = NULL;
  
  	ackskb->dev = lp->dev;
  
  	ret = sock_queue_err_skb(sk, ackskb);
  	if (ret)
  		kfree_skb(ackskb);
  
  	local_irq_enable();
  };

  struct net_device *alloc_arcdev(const char *name)

  {
  	struct net_device *dev;
  
  	dev = alloc_netdev(sizeof(struct arcnet_local),

  			   name && *name ? name : "arc%d", NET_NAME_UNKNOWN,
  			   arcdev_setup);

  	if (dev) {

  		struct arcnet_local *lp = netdev_priv(dev);

  		lp->dev = dev;

  		spin_lock_init(&lp->lock);

  		timer_setup(&lp->timer, arcnet_timer, 0);

  	}
  
  	return dev;
  }

  EXPORT_SYMBOL(alloc_arcdev);

  /* Open/initialize the board.  This is called sometime after booting when

   * the 'ifconfig' program is run.
   *
   * This routine should set everything up anew at each open, even registers
   * that "should" only need to be set once at boot, so that there is
   * non-reboot way to recover if something goes wrong.
   */

  int arcnet_open(struct net_device *dev)

  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	int count, newmtu, error;

  	arc_printk(D_INIT, dev, "opened.");

  
  	if (!try_module_get(lp->hw.owner))
  		return -ENODEV;

  	if (BUGLVL(D_PROTO)) {

  		arc_printk(D_PROTO, dev, "protocol map (default is '%c'): ",
  			   arc_proto_default->suffix);

  		for (count = 0; count < 256; count++)

  			arc_cont(D_PROTO, "%c", arc_proto_map[count]->suffix);
  		arc_cont(D_PROTO, "
  ");

  	}

  	tasklet_init(&lp->reply_tasklet, arcnet_reply_tasklet,
  		     (unsigned long)lp);

  	arc_printk(D_INIT, dev, "arcnet_open: resetting card.
  ");

  
  	/* try to put the card in a defined state - if it fails the first
  	 * time, actually reset it.
  	 */
  	error = -ENODEV;

  	if (lp->hw.reset(dev, 0) && lp->hw.reset(dev, 1))

  		goto out_module_put;
  
  	newmtu = choose_mtu();
  	if (newmtu < dev->mtu)
  		dev->mtu = newmtu;

  	arc_printk(D_INIT, dev, "arcnet_open: mtu: %d.
  ", dev->mtu);

  
  	/* autodetect the encapsulation for each host. */
  	memset(lp->default_proto, 0, sizeof(lp->default_proto));
  
  	/* the broadcast address is special - use the 'bcast' protocol */
  	for (count = 0; count < 256; count++) {
  		if (arc_proto_map[count] == arc_bcast_proto) {
  			lp->default_proto[0] = count;
  			break;
  		}
  	}
  
  	/* initialize buffers */
  	atomic_set(&lp->buf_lock, 1);
  
  	lp->next_buf = lp->first_free_buf = 0;
  	release_arcbuf(dev, 0);
  	release_arcbuf(dev, 1);
  	release_arcbuf(dev, 2);
  	release_arcbuf(dev, 3);
  	lp->cur_tx = lp->next_tx = -1;
  	lp->cur_rx = -1;
  
  	lp->rfc1201.sequence = 1;
  
  	/* bring up the hardware driver */
  	if (lp->hw.open)
  		lp->hw.open(dev);
  
  	if (dev->dev_addr[0] == 0)

  		arc_printk(D_NORMAL, dev, "WARNING!  Station address 00 is reserved for broadcasts!
  ");

  	else if (dev->dev_addr[0] == 255)

  		arc_printk(D_NORMAL, dev, "WARNING!  Station address FF may confuse DOS networking programs!
  ");

  	arc_printk(D_DEBUG, dev, "%s: %d: %s
  ", __FILE__, __LINE__, __func__);

  	if (lp->hw.status(dev) & RESETflag) {

  		arc_printk(D_DEBUG, dev, "%s: %d: %s
  ",
  			   __FILE__, __LINE__, __func__);

  		lp->hw.command(dev, CFLAGScmd | RESETclear);

  	}

  	arc_printk(D_DEBUG, dev, "%s: %d: %s
  ", __FILE__, __LINE__, __func__);

  	/* make sure we're ready to receive IRQ's. */

  	lp->hw.intmask(dev, 0);

  	udelay(1);		/* give it time to set the mask before
  				 * we reset it again. (may not even be
  				 * necessary)
  				 */

  	arc_printk(D_DEBUG, dev, "%s: %d: %s
  ", __FILE__, __LINE__, __func__);

  	lp->intmask = NORXflag | RECONflag;

  	lp->hw.intmask(dev, lp->intmask);

  	arc_printk(D_DEBUG, dev, "%s: %d: %s
  ", __FILE__, __LINE__, __func__);

  	netif_carrier_off(dev);

  	netif_start_queue(dev);

  	mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));

  	arcnet_led_event(dev, ARCNET_LED_EVENT_OPEN);

  	return 0;
  
   out_module_put:
  	module_put(lp->hw.owner);
  	return error;
  }

  EXPORT_SYMBOL(arcnet_open);

  /* The inverse routine to arcnet_open - shuts down the card. */

  int arcnet_close(struct net_device *dev)

  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	arcnet_led_event(dev, ARCNET_LED_EVENT_STOP);

  	del_timer_sync(&lp->timer);

  	netif_stop_queue(dev);

  	netif_carrier_off(dev);

  	tasklet_kill(&lp->reply_tasklet);

  	/* flush TX and disable RX */

  	lp->hw.intmask(dev, 0);
  	lp->hw.command(dev, NOTXcmd);	/* stop transmit */
  	lp->hw.command(dev, NORXcmd);	/* disable receive */

  	mdelay(1);
  
  	/* shut down the card */
  	lp->hw.close(dev);
  	module_put(lp->hw.owner);
  	return 0;
  }

  EXPORT_SYMBOL(arcnet_close);

  static int arcnet_header(struct sk_buff *skb, struct net_device *dev,

  			 unsigned short type, const void *daddr,
  			 const void *saddr, unsigned len)

  {

  	const struct arcnet_local *lp = netdev_priv(dev);

  	uint8_t _daddr, proto_num;
  	struct ArcProto *proto;

  	arc_printk(D_DURING, dev,
  		   "create header from %d to %d; protocol %d (%Xh); size %u.
  ",
  		   saddr ? *(uint8_t *)saddr : -1,
  		   daddr ? *(uint8_t *)daddr : -1,
  		   type, type, len);

  	if (skb->len != 0 && len != skb->len)

  		arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!
  ",
  			   skb->len, len);

  	/* Type is host order - ? */
  	if (type == ETH_P_ARCNET) {
  		proto = arc_raw_proto;

  		arc_printk(D_DEBUG, dev, "arc_raw_proto used. proto='%c'
  ",
  			   proto->suffix);

  		_daddr = daddr ? *(uint8_t *)daddr : 0;

  	} else if (!daddr) {

  		/* if the dest addr isn't provided, we can't choose an
  		 * encapsulation!  Store the packet type (eg. ETH_P_IP)
  		 * for now, and we'll push on a real header when we do
  		 * rebuild_header.

  		 */

  		*(uint16_t *)skb_push(skb, 2) = type;

  		/* XXX: Why not use skb->mac_len? */

  		if (skb->network_header - skb->mac_header != 2)

  			arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  diff (%u) is not 2!
  ",
  				   skb->network_header - skb->mac_header);

  		return -2;	/* return error -- can't transmit yet! */

  	} else {

  		/* otherwise, we can just add the header as usual. */

  		_daddr = *(uint8_t *)daddr;

  		proto_num = lp->default_proto[_daddr];
  		proto = arc_proto_map[proto_num];

  		arc_printk(D_DURING, dev, "building header for %02Xh using protocol '%c'
  ",
  			   proto_num, proto->suffix);

  		if (proto == &arc_proto_null && arc_bcast_proto != proto) {

  			arc_printk(D_DURING, dev, "actually, let's use '%c' instead.
  ",
  				   arc_bcast_proto->suffix);

  			proto = arc_bcast_proto;
  		}
  	}
  	return proto->build_header(skb, dev, type, _daddr);
  }

  /* Called by the kernel in order to transmit a packet. */

  netdev_tx_t arcnet_send_packet(struct sk_buff *skb,

  			       struct net_device *dev)

  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	struct archdr *pkt;
  	struct arc_rfc1201 *soft;
  	struct ArcProto *proto;
  	int txbuf;
  	unsigned long flags;

  	int retval;

  	arc_printk(D_DURING, dev,
  		   "transmit requested (status=%Xh, txbufs=%d/%d, len=%d, protocol %x)
  ",

  		   lp->hw.status(dev), lp->cur_tx, lp->next_tx, skb->len, skb->protocol);

  	pkt = (struct archdr *)skb->data;

  	soft = &pkt->soft.rfc1201;
  	proto = arc_proto_map[soft->proto];

  	arc_printk(D_SKB_SIZE, dev, "skb: transmitting %d bytes to %02X
  ",
  		   skb->len, pkt->hard.dest);

  	if (BUGLVL(D_SKB))
  		arcnet_dump_skb(dev, skb, "tx");

  
  	/* fits in one packet? */
  	if (skb->len - ARC_HDR_SIZE > XMTU && !proto->continue_tx) {

  		arc_printk(D_NORMAL, dev, "fixme: packet too large: compensating badly!
  ");

  		dev_kfree_skb(skb);

  		return NETDEV_TX_OK;	/* don't try again */

  	}
  
  	/* We're busy transmitting a packet... */
  	netif_stop_queue(dev);
  
  	spin_lock_irqsave(&lp->lock, flags);

  	lp->hw.intmask(dev, 0);

  	if (lp->next_tx == -1)

  		txbuf = get_arcbuf(dev);

  	else

  		txbuf = -1;

  	if (txbuf != -1) {

  		lp->outgoing.skb = skb;

  		if (proto->prepare_tx(dev, pkt, skb->len, txbuf) &&
  		    !proto->ack_tx) {
  			/* done right away and we don't want to acknowledge

  			 *  the package later - forget about it now
  			 */

  			dev->stats.tx_bytes += skb->len;

  		} else {
  			/* do it the 'split' way */
  			lp->outgoing.proto = proto;
  			lp->outgoing.skb = skb;
  			lp->outgoing.pkt = pkt;
  
  			if (proto->continue_tx &&
  			    proto->continue_tx(dev, txbuf)) {

  				arc_printk(D_NORMAL, dev,
  					   "bug! continue_tx finished the first time! (proto='%c')
  ",
  					   proto->suffix);

  			}
  		}

  		retval = NETDEV_TX_OK;

  		lp->next_tx = txbuf;
  	} else {

  		retval = NETDEV_TX_BUSY;

  	}

  	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x
  ",

  		   __FILE__, __LINE__, __func__, lp->hw.status(dev));

  	/* make sure we didn't ignore a TX IRQ while we were in here */

  	lp->hw.intmask(dev, 0);

  	arc_printk(D_DEBUG, dev, "%s: %d: %s
  ", __FILE__, __LINE__, __func__);

  	lp->intmask |= TXFREEflag | EXCNAKflag;

  	lp->hw.intmask(dev, lp->intmask);

  	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x
  ",

  		   __FILE__, __LINE__, __func__, lp->hw.status(dev));

  	arcnet_led_event(dev, ARCNET_LED_EVENT_TX);

  	spin_unlock_irqrestore(&lp->lock, flags);

  	return retval;		/* no need to try again */

  }

  EXPORT_SYMBOL(arcnet_send_packet);

  /* Actually start transmitting a packet that was loaded into a buffer

   * by prepare_tx.  This should _only_ be called by the interrupt handler.
   */
  static int go_tx(struct net_device *dev)
  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	arc_printk(D_DURING, dev, "go_tx: status=%Xh, intmask=%Xh, next_tx=%d, cur_tx=%d
  ",

  		   lp->hw.status(dev), lp->intmask, lp->next_tx, lp->cur_tx);

  
  	if (lp->cur_tx != -1 || lp->next_tx == -1)
  		return 0;

  	if (BUGLVL(D_TX))
  		arcnet_dump_packet(dev, lp->next_tx, "go_tx", 0);

  
  	lp->cur_tx = lp->next_tx;
  	lp->next_tx = -1;
  
  	/* start sending */

  	lp->hw.command(dev, TXcmd | (lp->cur_tx << 3));

  	dev->stats.tx_packets++;

  	lp->lasttrans_dest = lp->lastload_dest;
  	lp->lastload_dest = 0;
  	lp->excnak_pending = 0;

  	lp->intmask |= TXFREEflag | EXCNAKflag;

  
  	return 1;
  }

  /* Called by the kernel when transmit times out */

  void arcnet_timeout(struct net_device *dev, unsigned int txqueue)

  {
  	unsigned long flags;

  	struct arcnet_local *lp = netdev_priv(dev);

  	int status = lp->hw.status(dev);

  	char *msg;
  
  	spin_lock_irqsave(&lp->lock, flags);
  	if (status & TXFREEflag) {	/* transmit _DID_ finish */
  		msg = " - missed IRQ?";
  	} else {
  		msg = "";

  		dev->stats.tx_aborted_errors++;

  		lp->timed_out = 1;

  		lp->hw.command(dev, NOTXcmd | (lp->cur_tx << 3));

  	}

  	dev->stats.tx_errors++;

  
  	/* make sure we didn't miss a TX or a EXC NAK IRQ */

  	lp->hw.intmask(dev, 0);

  	lp->intmask |= TXFREEflag | EXCNAKflag;

  	lp->hw.intmask(dev, lp->intmask);

  	spin_unlock_irqrestore(&lp->lock, flags);

  	if (time_after(jiffies, lp->last_timeout + 10 * HZ)) {

  		arc_printk(D_EXTRA, dev, "tx timed out%s (status=%Xh, intmask=%Xh, dest=%02Xh)
  ",
  			   msg, status, lp->intmask, lp->lasttrans_dest);

  		lp->last_timeout = jiffies;
  	}
  
  	if (lp->cur_tx == -1)
  		netif_wake_queue(dev);
  }

  EXPORT_SYMBOL(arcnet_timeout);

  /* The typical workload of the driver: Handle the network interface

   * interrupts. Establish which device needs attention, and call the correct
   * chipset interrupt handler.
   */

  irqreturn_t arcnet_interrupt(int irq, void *dev_id)

  {
  	struct net_device *dev = dev_id;
  	struct arcnet_local *lp;
  	int recbuf, status, diagstatus, didsomething, boguscount;

  	unsigned long flags;

  	int retval = IRQ_NONE;

  	arc_printk(D_DURING, dev, "
  ");

  	arc_printk(D_DURING, dev, "in arcnet_interrupt
  ");

  
  	lp = netdev_priv(dev);

  	BUG_ON(!lp);

  	spin_lock_irqsave(&lp->lock, flags);

  	/* RESET flag was enabled - if device is not running, we must
  	 * clear it right away (but nothing else).

  	 */
  	if (!netif_running(dev)) {

  		if (lp->hw.status(dev) & RESETflag)
  			lp->hw.command(dev, CFLAGScmd | RESETclear);
  		lp->hw.intmask(dev, 0);

  		spin_unlock_irqrestore(&lp->lock, flags);

  		return retval;

  	}

  	arc_printk(D_DURING, dev, "in arcnet_inthandler (status=%Xh, intmask=%Xh)
  ",

  		   lp->hw.status(dev), lp->intmask);

  
  	boguscount = 5;
  	do {

  		status = lp->hw.status(dev);

  		diagstatus = (status >> 8) & 0xFF;

  		arc_printk(D_DEBUG, dev, "%s: %d: %s: status=%x
  ",
  			   __FILE__, __LINE__, __func__, status);

  		didsomething = 0;

  		/* RESET flag was enabled - card is resetting and if RX is

  		 * disabled, it's NOT because we just got a packet.

  		 *

  		 * The card is in an undefined state.
  		 * Clear it out and start over.

  		 */
  		if (status & RESETflag) {

  			arc_printk(D_NORMAL, dev, "spurious reset (status=%Xh)
  ",
  				   status);

  			arcnet_close(dev);
  			arcnet_open(dev);
  
  			/* get out of the interrupt handler! */
  			break;
  		}

  		/* RX is inhibited - we must have received something.
  		 * Prepare to receive into the next buffer.

  		 *

  		 * We don't actually copy the received packet from the card
  		 * until after the transmit handler runs (and possibly
  		 * launches the next tx); this should improve latency slightly
  		 * if we get both types of interrupts at once.

  		 */
  		recbuf = -1;
  		if (status & lp->intmask & NORXflag) {
  			recbuf = lp->cur_rx;

  			arc_printk(D_DURING, dev, "Buffer #%d: receive irq (status=%Xh)
  ",
  				   recbuf, status);

  
  			lp->cur_rx = get_arcbuf(dev);
  			if (lp->cur_rx != -1) {

  				arc_printk(D_DURING, dev, "enabling receive to buffer #%d
  ",
  					   lp->cur_rx);

  				lp->hw.command(dev, RXcmd | (lp->cur_rx << 3) | RXbcasts);

  			}
  			didsomething++;
  		}

  		if ((diagstatus & EXCNAKflag)) {

  			arc_printk(D_DURING, dev, "EXCNAK IRQ (diagstat=%Xh)
  ",
  				   diagstatus);

  			lp->hw.command(dev, NOTXcmd);      /* disable transmit */

  			lp->excnak_pending = 1;

  			lp->hw.command(dev, EXCNAKclear);

  			lp->intmask &= ~(EXCNAKflag);

  			didsomething++;
  		}

  		/* a transmit finished, and we're interested in it. */
  		if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {

  			int ackstatus;

  			lp->intmask &= ~(TXFREEflag | EXCNAKflag);

  			if (status & TXACKflag)
  				ackstatus = 2;
  			else if (lp->excnak_pending)
  				ackstatus = 1;
  			else
  				ackstatus = 0;

  			arc_printk(D_DURING, dev, "TX IRQ (stat=%Xh)
  ",
  				   status);

  
  			if (lp->cur_tx != -1 && !lp->timed_out) {

  				if (!(status & TXACKflag)) {

  					if (lp->lasttrans_dest != 0) {

  						arc_printk(D_EXTRA, dev,
  							   "transmit was not acknowledged! (status=%Xh, dest=%02Xh)
  ",
  							   status,
  							   lp->lasttrans_dest);

  						dev->stats.tx_errors++;
  						dev->stats.tx_carrier_errors++;

  					} else {

  						arc_printk(D_DURING, dev,
  							   "broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)
  ",
  							   status,
  							   lp->lasttrans_dest);

  					}
  				}
  
  				if (lp->outgoing.proto &&
  				    lp->outgoing.proto->ack_tx) {

  					lp->outgoing.proto
  						->ack_tx(dev, ackstatus);

  				}

  				lp->reply_status = ackstatus;
  				tasklet_hi_schedule(&lp->reply_tasklet);

  			}
  			if (lp->cur_tx != -1)
  				release_arcbuf(dev, lp->cur_tx);
  
  			lp->cur_tx = -1;
  			lp->timed_out = 0;
  			didsomething++;
  
  			/* send another packet if there is one */
  			go_tx(dev);
  
  			/* continue a split packet, if any */

  			if (lp->outgoing.proto &&
  			    lp->outgoing.proto->continue_tx) {

  				int txbuf = get_arcbuf(dev);

  				if (txbuf != -1) {
  					if (lp->outgoing.proto->continue_tx(dev, txbuf)) {
  						/* that was the last segment */

  						dev->stats.tx_bytes += lp->outgoing.skb->len;

  						if (!lp->outgoing.proto->ack_tx) {

  							dev_kfree_skb_irq(lp->outgoing.skb);
  							lp->outgoing.proto = NULL;
  						}

  					}
  					lp->next_tx = txbuf;
  				}
  			}
  			/* inform upper layers of idleness, if necessary */
  			if (lp->cur_tx == -1)
  				netif_wake_queue(dev);
  		}
  		/* now process the received packet, if any */
  		if (recbuf != -1) {

  			if (BUGLVL(D_RX))
  				arcnet_dump_packet(dev, recbuf, "rx irq", 0);

  
  			arcnet_rx(dev, recbuf);
  			release_arcbuf(dev, recbuf);
  
  			didsomething++;
  		}
  		if (status & lp->intmask & RECONflag) {

  			lp->hw.command(dev, CFLAGScmd | CONFIGclear);

  			dev->stats.tx_carrier_errors++;

  			arc_printk(D_RECON, dev, "Network reconfiguration detected (status=%Xh)
  ",
  				   status);

  			if (netif_carrier_ok(dev)) {
  				netif_carrier_off(dev);
  				netdev_info(dev, "link down
  ");
  			}
  			mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));

  			arcnet_led_event(dev, ARCNET_LED_EVENT_RECON);

  			/* MYRECON bit is at bit 7 of diagstatus */

  			if (diagstatus & 0x80)

  				arc_printk(D_RECON, dev, "Put out that recon myself
  ");

  
  			/* is the RECON info empty or old? */
  			if (!lp->first_recon || !lp->last_recon ||

  			    time_after(jiffies, lp->last_recon + HZ * 10)) {

  				if (lp->network_down)

  					arc_printk(D_NORMAL, dev, "reconfiguration detected: cabling restored?
  ");

  				lp->first_recon = lp->last_recon = jiffies;
  				lp->num_recons = lp->network_down = 0;

  				arc_printk(D_DURING, dev, "recon: clearing counters.
  ");

  			} else {	/* add to current RECON counter */
  				lp->last_recon = jiffies;
  				lp->num_recons++;

  				arc_printk(D_DURING, dev, "recon: counter=%d, time=%lds, net=%d
  ",
  					   lp->num_recons,
  					   (lp->last_recon - lp->first_recon) / HZ,
  					   lp->network_down);

  
  				/* if network is marked up;
  				 * and first_recon and last_recon are 60+ apart;
  				 * and the average no. of recons counted is
  				 *    > RECON_THRESHOLD/min;
  				 * then print a warning message.
  				 */

  				if (!lp->network_down &&
  				    (lp->last_recon - lp->first_recon) <= HZ * 60 &&
  				    lp->num_recons >= RECON_THRESHOLD) {

  					lp->network_down = 1;

  					arc_printk(D_NORMAL, dev, "many reconfigurations detected: cabling problem?
  ");

  				} else if (!lp->network_down &&
  					   lp->last_recon - lp->first_recon > HZ * 60) {

  					/* reset counters if we've gone for
  					 *  over a minute.
  					 */

  					lp->first_recon = lp->last_recon;
  					lp->num_recons = 1;
  				}
  			}

  		} else if (lp->network_down &&

  			   time_after(jiffies, lp->last_recon + HZ * 10)) {

  			if (lp->network_down)

  				arc_printk(D_NORMAL, dev, "cabling restored?
  ");

  			lp->first_recon = lp->last_recon = 0;
  			lp->num_recons = lp->network_down = 0;

  			arc_printk(D_DURING, dev, "not recon: clearing counters anyway.
  ");

  			netif_carrier_on(dev);

  		}

  		if (didsomething)

  			retval |= IRQ_HANDLED;

  	} while (--boguscount && didsomething);

  	arc_printk(D_DURING, dev, "arcnet_interrupt complete (status=%Xh, count=%d)
  ",

  		   lp->hw.status(dev), boguscount);

  	arc_printk(D_DURING, dev, "
  ");

  	lp->hw.intmask(dev, 0);

  	udelay(1);

  	lp->hw.intmask(dev, lp->intmask);

  	spin_unlock_irqrestore(&lp->lock, flags);

  	return retval;
  }

  EXPORT_SYMBOL(arcnet_interrupt);

  /* This is a generic packet receiver that calls arcnet??_rx depending on the

   * protocol ID found.
   */

  static void arcnet_rx(struct net_device *dev, int bufnum)

  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	union {
  		struct archdr pkt;
  		char buf[512];
  	} rxdata;

  	struct arc_rfc1201 *soft;
  	int length, ofs;

  	soft = &rxdata.pkt.soft.rfc1201;

  	lp->hw.copy_from_card(dev, bufnum, 0, &rxdata.pkt, ARC_HDR_SIZE);
  	if (rxdata.pkt.hard.offset[0]) {
  		ofs = rxdata.pkt.hard.offset[0];

  		length = 256 - ofs;
  	} else {

  		ofs = rxdata.pkt.hard.offset[1];

  		length = 512 - ofs;
  	}
  
  	/* get the full header, if possible */

  	if (sizeof(rxdata.pkt.soft) <= length) {
  		lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(rxdata.pkt.soft));

  	} else {

  		memset(&rxdata.pkt.soft, 0, sizeof(rxdata.pkt.soft));

  		lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
  	}

  	arc_printk(D_DURING, dev, "Buffer #%d: received packet from %02Xh to %02Xh (%d+4 bytes)
  ",

  		   bufnum, rxdata.pkt.hard.source, rxdata.pkt.hard.dest, length);

  	dev->stats.rx_packets++;
  	dev->stats.rx_bytes += length + ARC_HDR_SIZE;

  
  	/* call the right receiver for the protocol */
  	if (arc_proto_map[soft->proto]->is_ip) {

  		if (BUGLVL(D_PROTO)) {

  			struct ArcProto

  			*oldp = arc_proto_map[lp->default_proto[rxdata.pkt.hard.source]],

  			*newp = arc_proto_map[soft->proto];
  
  			if (oldp != newp) {

  				arc_printk(D_PROTO, dev,
  					   "got protocol %02Xh; encap for host %02Xh is now '%c' (was '%c')
  ",

  					   soft->proto, rxdata.pkt.hard.source,

  					   newp->suffix, oldp->suffix);

  			}
  		}
  
  		/* broadcasts will always be done with the last-used encap. */
  		lp->default_proto[0] = soft->proto;
  
  		/* in striking contrast, the following isn't a hack. */

  		lp->default_proto[rxdata.pkt.hard.source] = soft->proto;

  	}
  	/* call the protocol-specific receiver. */

  	arc_proto_map[soft->proto]->rx(dev, bufnum, &rxdata.pkt, length);

  }

  static void null_rx(struct net_device *dev, int bufnum,
  		    struct archdr *pkthdr, int length)
  {

  	arc_printk(D_PROTO, dev,
  		   "rx: don't know how to deal with proto %02Xh from host %02Xh.
  ",
  		   pkthdr->soft.rfc1201.proto, pkthdr->hard.source);

  }

  static int null_build_header(struct sk_buff *skb, struct net_device *dev,
  			     unsigned short type, uint8_t daddr)
  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	arc_printk(D_PROTO, dev,
  		   "tx: can't build header for encap %02Xh; load a protocol driver.
  ",
  		   lp->default_proto[daddr]);

  
  	/* always fails */
  	return 0;
  }

  /* the "do nothing" prepare_tx function warns that there's nothing to do. */
  static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
  			   int length, int bufnum)
  {

  	struct arcnet_local *lp = netdev_priv(dev);

  	struct arc_hardware newpkt;

  	arc_printk(D_PROTO, dev, "tx: no encap for this host; load a protocol driver.
  ");

  
  	/* send a packet to myself -- will never get received, of course */
  	newpkt.source = newpkt.dest = dev->dev_addr[0];
  
  	/* only one byte of actual data (and it's random) */
  	newpkt.offset[0] = 0xFF;
  
  	lp->hw.copy_to_card(dev, bufnum, 0, &newpkt, ARC_HDR_SIZE);
  
  	return 1;		/* done */
  }