aboutsummaryrefslogblamecommitdiffstats
path: root/drivers/net/arcnet/arcnet.c
blob: 12ef52c193a39a2e1743bda3292110c4f76279d8 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599






















































































































































































































































































































































































































































































































































































































                                                                                                   
                            
















                                                                                      
                                                             






                                                 




                                        












                                                                           

                                    






                                                                             

                                           

                                    

                                        














                                                                                             
                                                          
























                                                                                   

































































































































































































































                                                                                                       


                                                                              






















































































































































































                                                                                                               
/*
 * 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 VERSION "arcnet: v3.93 BETA 2000/04/29 - by Avery Pennarun et al.\n"

#include <linux/module.h>
#include <linux/config.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/arcdevice.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);


/*
 * 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], *arc_proto_default,
   *arc_bcast_proto, *arc_raw_proto;

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(arc_proto_map);
EXPORT_SYMBOL(arc_proto_default);
EXPORT_SYMBOL(arc_bcast_proto);
EXPORT_SYMBOL(arc_raw_proto);
EXPORT_SYMBOL(arc_proto_null);
EXPORT_SYMBOL(arcnet_unregister_proto);
EXPORT_SYMBOL(arcnet_debug);
EXPORT_SYMBOL(alloc_arcdev);
EXPORT_SYMBOL(arcnet_interrupt);

/* Internal function prototypes */
static int arcnet_open(struct net_device *dev);
static int arcnet_close(struct net_device *dev);
static int arcnet_send_packet(struct sk_buff *skb, struct net_device *dev);
static void arcnet_timeout(struct net_device *dev);
static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
			 unsigned short type, void *daddr, void *saddr,
			 unsigned len);
static int arcnet_rebuild_header(struct sk_buff *skb);
static struct net_device_stats *arcnet_get_stats(struct net_device *dev);
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;

	printk(VERSION);

#ifdef ALPHA_WARNING
	BUGLVL(D_EXTRA) {
		printk("arcnet: ***\n"
		"arcnet: * Read arcnet.txt for important release notes!\n"
		       "arcnet: *\n"
		       "arcnet: * This is an ALPHA version! (Last stable release: v3.02)  E-mail\n"
		       "arcnet: * me if you have any questions, comments, or bug reports.\n"
		       "arcnet: ***\n");
	}
#endif

	/* 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;

	BUGLVL(D_DURING)
	    printk("arcnet: struct sizes: %Zd %Zd %Zd %Zd %Zd\n",
		 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)
{
	int i;

	printk(KERN_DEBUG "%6s: skb dump (%s) follows:", dev->name, desc);
	for (i = 0; i < skb->len; i++) {
		if (i % 16 == 0)
			printk("\n" KERN_DEBUG "[%04X] ", i);
		printk("%02X ", ((u_char *) skb->data)[i]);
	}
	printk("\n");
}

EXPORT_SYMBOL(arcnet_dump_skb);
#endif


/*
 * Dump the contents of an ARCnet buffer
 */
#if (ARCNET_DEBUG_MAX & (D_RX | D_TX))
void arcnet_dump_packet(struct net_device *dev, int bufnum, char *desc,
			int take_arcnet_lock)
{
	struct arcnet_local *lp = dev->priv;
	int i, length;
	unsigned long flags = 0;
	static uint8_t buf[512];

	/* 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);

	printk(KERN_DEBUG "%6s: packet dump (%s) follows:", dev->name, desc);
	for (i = 0; i < length; i++) {
		if (i % 16 == 0)
			printk("\n" KERN_DEBUG "[%04X] ", i);
		printk("%02X ", buf[i]);
	}
	printk("\n");

}

EXPORT_SYMBOL(arcnet_dump_packet);
#endif


/*
 * 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;
	}
}


/*
 * 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 = dev->priv;
	int i;

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

	BUGLVL(D_DURING) {
		BUGMSG(D_DURING, "release_arcbuf: freed #%d; buffer queue is now: ",
		       bufnum);
		for (i = lp->next_buf; i != lp->first_free_buf; i = (i+1) % 5)
			BUGMSG2(D_DURING, "#%d ", lp->buf_queue[i]);
		BUGMSG2(D_DURING, "\n");
	}
}


/*
 * 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 = dev->priv;
	int buf = -1, i;

	if (!atomic_dec_and_test(&lp->buf_lock)) {
		/* already in this function */
		BUGMSG(D_NORMAL, "get_arcbuf: overlap (%d)!\n",
		       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)
			BUGMSG(D_NORMAL, "get_arcbuf: BUG: no buffers are available??\n");
		else {
			buf = lp->buf_queue[lp->next_buf++];
			lp->next_buf %= 5;
		}
	}


	BUGLVL(D_DURING) {
		BUGMSG(D_DURING, "get_arcbuf: got #%d; buffer queue is now: ", buf);
		for (i = lp->next_buf; i != lp->first_free_buf; i = (i+1) % 5)
			BUGMSG2(D_DURING, "#%d ", lp->buf_queue[i]);
		BUGMSG2(D_DURING, "\n");
	}

	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;
}


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

	/*
	 * Put in this stuff here, so we don't have to export the symbols to
	 * the chipset drivers.
	 */
	dev->open = arcnet_open;
	dev->stop = arcnet_close;
	dev->hard_start_xmit = arcnet_send_packet;
	dev->tx_timeout = arcnet_timeout;
	dev->get_stats = arcnet_get_stats;
	dev->hard_header = arcnet_header;
	dev->rebuild_header = arcnet_rebuild_header;
}

struct net_device *alloc_arcdev(char *name)
{
	struct net_device *dev;

	dev = alloc_netdev(sizeof(struct arcnet_local),
			   name && *name ? name : "arc%d", arcdev_setup);
	if(dev) {
		struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
		spin_lock_init(&lp->lock);
	}

	return dev;
}

/*
 * 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.
 */
static int arcnet_open(struct net_device *dev)
{
	struct arcnet_local *lp = dev->priv;
	int count, newmtu, error;

	BUGMSG(D_INIT,"opened.");

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

	BUGLVL(D_PROTO) {
		int count;
		BUGMSG(D_PROTO, "protocol map (default is '%c'): ",
		       arc_proto_default->suffix);
		for (count = 0; count < 256; count++)
			BUGMSG2(D_PROTO, "%c", arc_proto_map[count]->suffix);
		BUGMSG2(D_PROTO, "\n");
	}


	BUGMSG(D_INIT, "arcnet_open: resetting card.\n");

	/* try to put the card in a defined state - if it fails the first
	 * time, actually reset it.
	 */
	error = -ENODEV;
	if (ARCRESET(0) && ARCRESET(1))
		goto out_module_put;

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

	BUGMSG(D_INIT, "arcnet_open: mtu: %d.\n", 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)
		BUGMSG(D_NORMAL, "WARNING!  Station address 00 is reserved "
		       "for broadcasts!\n");
	else if (dev->dev_addr[0] == 255)
		BUGMSG(D_NORMAL, "WARNING!  Station address FF may confuse "
		       "DOS networking programs!\n");

	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	if (ASTATUS() & RESETflag) {
	  	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
		ACOMMAND(CFLAGScmd | RESETclear);
	}


	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	/* make sure we're ready to receive IRQ's. */
	AINTMASK(0);
	udelay(1);		/* give it time to set the mask before
				 * we reset it again. (may not even be
				 * necessary)
				 */
	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	lp->intmask = NORXflag | RECONflag;
	AINTMASK(lp->intmask);
	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);

	netif_start_queue(dev);

	return 0;

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


/* The inverse routine to arcnet_open - shuts down the card. */
static int arcnet_close(struct net_device *dev)
{
	struct arcnet_local *lp = dev->priv;

	netif_stop_queue(dev);

	/* flush TX and disable RX */
	AINTMASK(0);
	ACOMMAND(NOTXcmd);	/* stop transmit */
	ACOMMAND(NORXcmd);	/* disable receive */
	mdelay(1);

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


static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
			 unsigned short type, void *daddr, void *saddr,
			 unsigned len)
{
	struct arcnet_local *lp = dev->priv;
	uint8_t _daddr, proto_num;
	struct ArcProto *proto;

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

	if (skb->len!=0 && len != skb->len)
		BUGMSG(D_NORMAL, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!\n",
		       skb->len, len);


  	/* Type is host order - ? */
  	if(type == ETH_P_ARCNET) {
  		proto = arc_raw_proto;
  		BUGMSG(D_DEBUG, "arc_raw_proto used. proto='%c'\n",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;
		if (skb->nh.raw - skb->mac.raw != 2)
			BUGMSG(D_NORMAL, "arcnet_header: Yikes!  diff (%d) is not 2!\n",
			       (int)(skb->nh.raw - skb->mac.raw));
		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];
		BUGMSG(D_DURING, "building header for %02Xh using protocol '%c'\n",
		       proto_num, proto->suffix);
		if (proto == &arc_proto_null && arc_bcast_proto != proto) {
			BUGMSG(D_DURING, "actually, let's use '%c' instead.\n",
			       arc_bcast_proto->suffix);
			proto = arc_bcast_proto;
		}
	}
	return proto->build_header(skb, dev, type, _daddr);
}


/* 
 * Rebuild the ARCnet hard header. This is called after an ARP (or in the
 * future other address resolution) has completed on this sk_buff. We now
 * let ARP fill in the destination field.
 */
static int arcnet_rebuild_header(struct sk_buff *skb)
{
	struct net_device *dev = skb->dev;
	struct arcnet_local *lp = dev->priv;
	int status = 0;		/* default is failure */
	unsigned short type;
	uint8_t daddr=0;
	struct ArcProto *proto;

	if (skb->nh.raw - skb->mac.raw != 2) {
		BUGMSG(D_NORMAL,
		     "rebuild_header: shouldn't be here! (hdrsize=%d)\n",
		     (int)(skb->nh.raw - skb->mac.raw));
		return 0;
	}
	type = *(uint16_t *) skb_pull(skb, 2);
	BUGMSG(D_DURING, "rebuild header for protocol %Xh\n", type);

	if (type == ETH_P_IP) {
#ifdef CONFIG_INET
		BUGMSG(D_DURING, "rebuild header for ethernet protocol %Xh\n", type);
		status = arp_find(&daddr, skb) ? 1 : 0;
		BUGMSG(D_DURING, " rebuilt: dest is %d; protocol %Xh\n",
		       daddr, type);
#endif
	} else {
		BUGMSG(D_NORMAL,
		       "I don't understand ethernet protocol %Xh addresses!\n", type);
		lp->stats.tx_errors++;
		lp->stats.tx_aborted_errors++;
	}

	/* if we couldn't resolve the address... give up. */
	if (!status)
		return 0;

	/* add the _real_ header this time! */
	proto = arc_proto_map[lp->default_proto[daddr]];
	proto->build_header(skb, dev, type, daddr);

	return 1;		/* success */
}



/* Called by the kernel in order to transmit a packet. */
static int arcnet_send_packet(struct sk_buff *skb, struct net_device *dev)
{
	struct arcnet_local *lp = dev->priv;
	struct archdr *pkt;
	struct arc_rfc1201 *soft;
	struct ArcProto *proto;
	int txbuf;
	unsigned long flags;
	int freeskb, retval;

	BUGMSG(D_DURING,
	       "transmit requested (status=%Xh, txbufs=%d/%d, len=%d, protocol %x)\n",
	       ASTATUS(), 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];

	BUGMSG(D_SKB_SIZE, "skb: transmitting %d bytes to %02X\n",
		skb->len, pkt->hard.dest);
	BUGLVL(D_SKB) arcnet_dump_skb(dev, skb, "tx");

	/* fits in one packet? */
	if (skb->len - ARC_HDR_SIZE > XMTU && !proto->continue_tx) {
		BUGMSG(D_NORMAL, "fixme: packet too large: compensating badly!\n");
		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);
	AINTMASK(0);
	if(lp->next_tx == -1)
		txbuf = get_arcbuf(dev);
	else {
		txbuf = -1;
	}
	if (txbuf != -1) {
		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 */
			lp->stats.tx_bytes += skb->len;
			freeskb = 1;
		} else {
			/* do it the 'split' way */
			lp->outgoing.proto = proto;
			lp->outgoing.skb = skb;
			lp->outgoing.pkt = pkt;

			freeskb = 0;

			if (proto->continue_tx &&
			    proto->continue_tx(dev, txbuf)) {
			  BUGMSG(D_NORMAL,
				 "bug! continue_tx finished the first time! "
				 "(proto='%c')\n", proto->suffix);
			}
		}
		retval = NETDEV_TX_OK;
		dev->trans_start = jiffies;
		lp->next_tx = txbuf;
	} else {
		retval = NETDEV_TX_BUSY;
		freeskb = 0;
	}

	BUGMSG(D_DEBUG, "%s: %d: %s, status: %x\n",__FILE__,__LINE__,__FUNCTION__,ASTATUS());
	/* make sure we didn't ignore a TX IRQ while we were in here */
	AINTMASK(0);

	BUGMSG(D_DEBUG, "%s: %d: %s\n",__FILE__,__LINE__,__FUNCTION__);
	lp->intmask |= TXFREEflag|EXCNAKflag;
	AINTMASK(lp->intmask);
	BUGMSG(D_DEBUG, "%s: %d: %s, status: %x\n",__FILE__,__LINE__,__FUNCTION__,ASTATUS());

	spin_unlock_irqrestore(&lp->lock, flags);
	if (freeskb) {
		dev_kfree_skb(skb);
	}
	return retval;		/* no need to try again */
}


/*
 * 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 = dev->priv;

	BUGMSG(D_DURING, "go_tx: status=%Xh, intmask=%Xh, next_tx=%d, cur_tx=%d\n",
	       ASTATUS(), lp->intmask, lp->next_tx, lp->cur_tx);

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

	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 */
	ACOMMAND(TXcmd | (lp->cur_tx << 3));

	lp->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 */
static void arcnet_timeout(struct net_device *dev)
{
	unsigned long flags;
	struct arcnet_local *lp = dev->priv;
	int status = ASTATUS();
	char *msg;

	spin_lock_irqsave(&lp->lock, flags);
	if (status & TXFREEflag) {	/* transmit _DID_ finish */
		msg = " - missed IRQ?";
	} else {
		msg = "";
		lp->stats.tx_aborted_errors++;
		lp->timed_out = 1;
		ACOMMAND(NOTXcmd | (lp->cur_tx << 3));
	}
	lp->stats.tx_errors++;

	/* make sure we didn't miss a TX or a EXC NAK IRQ */
	AINTMASK(0);
	lp->intmask |= TXFREEflag|EXCNAKflag;
	AINTMASK(lp->intmask);
	
	spin_unlock_irqrestore(&lp->lock, flags);

	if (jiffies - lp->last_timeout > 10*HZ) {
		BUGMSG(D_EXTRA, "tx timed out%s (status=%Xh, intmask=%Xh, dest=%02Xh)\n",
		       msg, status, lp->intmask, lp->lasttrans_dest);
		lp->last_timeout = jiffies;
	}

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


/*
 * 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 pt_regs *regs)
{
	struct net_device *dev = dev_id;
	struct arcnet_local *lp;
	int recbuf, status, diagstatus, didsomething, boguscount;
	int retval = IRQ_NONE;

	BUGMSG(D_DURING, "\n");

	BUGMSG(D_DURING, "in arcnet_interrupt\n");
	
	lp = dev->priv;
	if (!lp)
		BUG();
		
	spin_lock(&lp->lock);

	/*
	 * RESET flag was enabled - if device is not running, we must clear it right
	 * away (but nothing else).
	 */
	if (!netif_running(dev)) {
		if (ASTATUS() & RESETflag)
			ACOMMAND(CFLAGScmd | RESETclear);
		AINTMASK(0);
		spin_unlock(&lp->lock);
		return IRQ_HANDLED;
	}

	BUGMSG(D_DURING, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
	       ASTATUS(), lp->intmask);

	boguscount = 5;
	do {
		status = ASTATUS();
                diagstatus = (status >> 8) & 0xFF;

		BUGMSG(D_DEBUG, "%s: %d: %s: status=%x\n",
			__FILE__,__LINE__,__FUNCTION__,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) {
			BUGMSG(D_NORMAL, "spurious reset (status=%Xh)\n", 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;
			BUGMSG(D_DURING, "Buffer #%d: receive irq (status=%Xh)\n",
			       recbuf, status);

			lp->cur_rx = get_arcbuf(dev);
			if (lp->cur_rx != -1) {
				BUGMSG(D_DURING, "enabling receive to buffer #%d\n",
				       lp->cur_rx);
				ACOMMAND(RXcmd | (lp->cur_rx << 3) | RXbcasts);
			}
			didsomething++;
		}

		if((diagstatus & EXCNAKflag)) {
			BUGMSG(D_DURING, "EXCNAK IRQ (diagstat=%Xh)\n",
			       diagstatus);

                        ACOMMAND(NOTXcmd);      /* disable transmit */
                        lp->excnak_pending = 1;

                        ACOMMAND(EXCNAKclear);
			lp->intmask &= ~(EXCNAKflag);
                        didsomething++;
                }


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

			BUGMSG(D_DURING, "TX IRQ (stat=%Xh)\n", status);

			if (lp->cur_tx != -1 && !lp->timed_out) {
				if(!(status & TXACKflag)) {
					if (lp->lasttrans_dest != 0) {
						BUGMSG(D_EXTRA,
						       "transmit was not acknowledged! "
						       "(status=%Xh, dest=%02Xh)\n",
						       status, lp->lasttrans_dest);
						lp->stats.tx_errors++;
						lp->stats.tx_carrier_errors++;
					} else {
						BUGMSG(D_DURING,
						       "broadcast was not acknowledged; that's normal "
						       "(status=%Xh, dest=%02Xh)\n",
						       status, lp->lasttrans_dest);
					}
				}

				if (lp->outgoing.proto &&
				    lp->outgoing.proto->ack_tx) {
				  int ackstatus;
				  if(status & TXACKflag)
                                    ackstatus=2;
                                  else if(lp->excnak_pending)
                                    ackstatus=1;
                                  else
                                    ackstatus=0;

                                  lp->outgoing.proto
                                    ->ack_tx(dev, ackstatus);
				}
			}
			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 */
						lp->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) {
			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) {
			ACOMMAND(CFLAGScmd | CONFIGclear);
			lp->stats.tx_carrier_errors++;

			BUGMSG(D_RECON, "Network reconfiguration detected (status=%Xh)\n",
			       status);
			/* MYRECON bit is at bit 7 of diagstatus */
			if(diagstatus & 0x80)
				BUGMSG(D_RECON,"Put out that recon myself\n");

			/* is the RECON info empty or old? */
			if (!lp->first_recon || !lp->last_recon ||
			    jiffies - lp->last_recon > HZ * 10) {
				if (lp->network_down)
					BUGMSG(D_NORMAL, "reconfiguration detected: cabling restored?\n");
				lp->first_recon = lp->last_recon = jiffies;
				lp->num_recons = lp->network_down = 0;

				BUGMSG(D_DURING, "recon: clearing counters.\n");
			} else {	/* add to current RECON counter */
				lp->last_recon = jiffies;
				lp->num_recons++;

				BUGMSG(D_DURING, "recon: counter=%d, time=%lds, net=%d\n",
				       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;
					BUGMSG(D_NORMAL, "many reconfigurations detected: cabling problem?\n");
				} 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 && jiffies - lp->last_recon > HZ * 10) {
			if (lp->network_down)
				BUGMSG(D_NORMAL, "cabling restored?\n");
			lp->first_recon = lp->last_recon = 0;
			lp->num_recons = lp->network_down = 0;

			BUGMSG(D_DURING, "not recon: clearing counters anyway.\n");
		}

		if(didsomething) {
			retval |= IRQ_HANDLED;
		}
	}
	while (--boguscount && didsomething);

	BUGMSG(D_DURING, "arcnet_interrupt complete (status=%Xh, count=%d)\n",
	       ASTATUS(), boguscount);
	BUGMSG(D_DURING, "\n");


	AINTMASK(0);
	udelay(1);
	AINTMASK(lp->intmask);
	
	spin_unlock(&lp->lock);
	return retval;
}


/*
 * This is a generic packet receiver that calls arcnet??_rx depending on the
 * protocol ID found.
 */
void arcnet_rx(struct net_device *dev, int bufnum)
{
	struct arcnet_local *lp = dev->priv;
	struct archdr pkt;
	struct arc_rfc1201 *soft;
	int length, ofs;

	soft = &pkt.soft.rfc1201;

	lp->hw.copy_from_card(dev, bufnum, 0, &pkt, sizeof(ARC_HDR_SIZE));
	if (pkt.hard.offset[0]) {
		ofs = pkt.hard.offset[0];
		length = 256 - ofs;
	} else {
		ofs = pkt.hard.offset[1];
		length = 512 - ofs;
	}

	/* get the full header, if possible */
	if (sizeof(pkt.soft) <= length)
		lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(pkt.soft));
	else {
		memset(&pkt.soft, 0, sizeof(pkt.soft));
		lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
	}

	BUGMSG(D_DURING, "Buffer #%d: received packet from %02Xh to %02Xh "
	       "(%d+4 bytes)\n",
	       bufnum, pkt.hard.source, pkt.hard.dest, length);

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

	/* call the right receiver for the protocol */
	if (arc_proto_map[soft->proto]->is_ip) {
		BUGLVL(D_PROTO) {
			struct ArcProto
			*oldp = arc_proto_map[lp->default_proto[pkt.hard.source]],
			*newp = arc_proto_map[soft->proto];

			if (oldp != newp) {
				BUGMSG(D_PROTO,
				       "got protocol %02Xh; encap for host %02Xh is now '%c'"
				       " (was '%c')\n", soft->proto, 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[pkt.hard.source] = soft->proto;
	}
	/* call the protocol-specific receiver. */
	arc_proto_map[soft->proto]->rx(dev, bufnum, &pkt, length);
}



/* 
 * Get the current statistics.  This may be called with the card open or
 * closed.
 */
static struct net_device_stats *arcnet_get_stats(struct net_device *dev)
{
	struct arcnet_local *lp = dev->priv;
	return &lp->stats;
}


static void null_rx(struct net_device *dev, int bufnum,
		    struct archdr *pkthdr, int length)
{
	BUGMSG(D_PROTO,
	"rx: don't know how to deal with proto %02Xh from host %02Xh.\n",
	       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 = dev->priv;

	BUGMSG(D_PROTO,
	       "tx: can't build header for encap %02Xh; load a protocol driver.\n",
	       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 = dev->priv;
	struct arc_hardware newpkt;

	BUGMSG(D_PROTO, "tx: no encap for this host; load a protocol driver.\n");

	/* 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 */
}