xref: /openbmc/linux/drivers/net/arcnet/arcnet.c (revision 372892ec1151c895c7dec362f3246f089690cfc7)
1 /*
2  * Linux ARCnet driver - device-independent routines
3  *
4  * Written 1997 by David Woodhouse.
5  * Written 1994-1999 by Avery Pennarun.
6  * Written 1999-2000 by Martin Mares <mj@ucw.cz>.
7  * Derived from skeleton.c by Donald Becker.
8  *
9  * Special thanks to Contemporary Controls, Inc. (www.ccontrols.com)
10  *  for sponsoring the further development of this driver.
11  *
12  * **********************
13  *
14  * The original copyright was as follows:
15  *
16  * skeleton.c Written 1993 by Donald Becker.
17  * Copyright 1993 United States Government as represented by the
18  * Director, National Security Agency.  This software may only be used
19  * and distributed according to the terms of the GNU General Public License as
20  * modified by SRC, incorporated herein by reference.
21  *
22  * **********************
23  *
24  * The change log is now in a file called ChangeLog in this directory.
25  *
26  * Sources:
27  *  - Crynwr arcnet.com/arcether.com packet drivers.
28  *  - arcnet.c v0.00 dated 1/1/94 and apparently by
29  *     Donald Becker - it didn't work :)
30  *  - skeleton.c v0.05 dated 11/16/93 by Donald Becker
31  *     (from Linux Kernel 1.1.45)
32  *  - RFC's 1201 and 1051 - re: TCP/IP over ARCnet
33  *  - The official ARCnet COM9026 data sheets (!) thanks to
34  *     Ken Cornetet <kcornete@nyx10.cs.du.edu>
35  *  - The official ARCnet COM20020 data sheets.
36  *  - Information on some more obscure ARCnet controller chips, thanks
37  *     to the nice people at SMSC.
38  *  - net/inet/eth.c (from kernel 1.1.50) for header-building info.
39  *  - Alternate Linux ARCnet source by V.Shergin <vsher@sao.stavropol.su>
40  *  - Textual information and more alternate source from Joachim Koenig
41  *     <jojo@repas.de>
42  */
43 
44 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45 
46 #include <linux/module.h>
47 #include <linux/types.h>
48 #include <linux/delay.h>
49 #include <linux/netdevice.h>
50 #include <linux/if_arp.h>
51 #include <net/arp.h>
52 #include <linux/init.h>
53 #include <linux/jiffies.h>
54 
55 #include "arcdevice.h"
56 #include "com9026.h"
57 
58 /* "do nothing" functions for protocol drivers */
59 static void null_rx(struct net_device *dev, int bufnum,
60 		    struct archdr *pkthdr, int length);
61 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
62 			     unsigned short type, uint8_t daddr);
63 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
64 			   int length, int bufnum);
65 
66 static void arcnet_rx(struct net_device *dev, int bufnum);
67 
68 /* one ArcProto per possible proto ID.  None of the elements of
69  * arc_proto_map are allowed to be NULL; they will get set to
70  * arc_proto_default instead.  It also must not be NULL; if you would like
71  * to set it to NULL, set it to &arc_proto_null instead.
72  */
73 struct ArcProto *arc_proto_map[256];
74 EXPORT_SYMBOL(arc_proto_map);
75 
76 struct ArcProto *arc_proto_default;
77 EXPORT_SYMBOL(arc_proto_default);
78 
79 struct ArcProto *arc_bcast_proto;
80 EXPORT_SYMBOL(arc_bcast_proto);
81 
82 struct ArcProto *arc_raw_proto;
83 EXPORT_SYMBOL(arc_raw_proto);
84 
85 static struct ArcProto arc_proto_null = {
86 	.suffix		= '?',
87 	.mtu		= XMTU,
88 	.is_ip          = 0,
89 	.rx		= null_rx,
90 	.build_header	= null_build_header,
91 	.prepare_tx	= null_prepare_tx,
92 	.continue_tx    = NULL,
93 	.ack_tx         = NULL
94 };
95 
96 /* Exported function prototypes */
97 int arcnet_debug = ARCNET_DEBUG;
98 EXPORT_SYMBOL(arcnet_debug);
99 
100 /* Internal function prototypes */
101 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
102 			 unsigned short type, const void *daddr,
103 			 const void *saddr, unsigned len);
104 static int go_tx(struct net_device *dev);
105 
106 static int debug = ARCNET_DEBUG;
107 module_param(debug, int, 0);
108 MODULE_LICENSE("GPL");
109 
110 static int __init arcnet_init(void)
111 {
112 	int count;
113 
114 	arcnet_debug = debug;
115 
116 	pr_info("arcnet loaded\n");
117 
118 	/* initialize the protocol map */
119 	arc_raw_proto = arc_proto_default = arc_bcast_proto = &arc_proto_null;
120 	for (count = 0; count < 256; count++)
121 		arc_proto_map[count] = arc_proto_default;
122 
123 	if (BUGLVL(D_DURING))
124 		pr_info("struct sizes: %Zd %Zd %Zd %Zd %Zd\n",
125 			sizeof(struct arc_hardware),
126 			sizeof(struct arc_rfc1201),
127 			sizeof(struct arc_rfc1051),
128 			sizeof(struct arc_eth_encap),
129 			sizeof(struct archdr));
130 
131 	return 0;
132 }
133 
134 static void __exit arcnet_exit(void)
135 {
136 }
137 
138 module_init(arcnet_init);
139 module_exit(arcnet_exit);
140 
141 /* Dump the contents of an sk_buff */
142 #if ARCNET_DEBUG_MAX & D_SKB
143 void arcnet_dump_skb(struct net_device *dev,
144 		     struct sk_buff *skb, char *desc)
145 {
146 	char hdr[32];
147 
148 	/* dump the packet */
149 	snprintf(hdr, sizeof(hdr), "%6s:%s skb->data:", dev->name, desc);
150 	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
151 		       16, 1, skb->data, skb->len, true);
152 }
153 EXPORT_SYMBOL(arcnet_dump_skb);
154 #endif
155 
156 /* Dump the contents of an ARCnet buffer */
157 #if (ARCNET_DEBUG_MAX & (D_RX | D_TX))
158 static void arcnet_dump_packet(struct net_device *dev, int bufnum,
159 			       char *desc, int take_arcnet_lock)
160 {
161 	struct arcnet_local *lp = netdev_priv(dev);
162 	int i, length;
163 	unsigned long flags = 0;
164 	static uint8_t buf[512];
165 	char hdr[32];
166 
167 	/* hw.copy_from_card expects IRQ context so take the IRQ lock
168 	 * to keep it single threaded
169 	 */
170 	if (take_arcnet_lock)
171 		spin_lock_irqsave(&lp->lock, flags);
172 
173 	lp->hw.copy_from_card(dev, bufnum, 0, buf, 512);
174 	if (take_arcnet_lock)
175 		spin_unlock_irqrestore(&lp->lock, flags);
176 
177 	/* if the offset[0] byte is nonzero, this is a 256-byte packet */
178 	length = (buf[2] ? 256 : 512);
179 
180 	/* dump the packet */
181 	snprintf(hdr, sizeof(hdr), "%6s:%s packet dump:", dev->name, desc);
182 	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
183 		       16, 1, buf, length, true);
184 }
185 
186 #else
187 
188 #define arcnet_dump_packet(dev, bufnum, desc, take_arcnet_lock) do { } while (0)
189 
190 #endif
191 
192 /* Unregister a protocol driver from the arc_proto_map.  Protocol drivers
193  * are responsible for registering themselves, but the unregister routine
194  * is pretty generic so we'll do it here.
195  */
196 void arcnet_unregister_proto(struct ArcProto *proto)
197 {
198 	int count;
199 
200 	if (arc_proto_default == proto)
201 		arc_proto_default = &arc_proto_null;
202 	if (arc_bcast_proto == proto)
203 		arc_bcast_proto = arc_proto_default;
204 	if (arc_raw_proto == proto)
205 		arc_raw_proto = arc_proto_default;
206 
207 	for (count = 0; count < 256; count++) {
208 		if (arc_proto_map[count] == proto)
209 			arc_proto_map[count] = arc_proto_default;
210 	}
211 }
212 EXPORT_SYMBOL(arcnet_unregister_proto);
213 
214 /* Add a buffer to the queue.  Only the interrupt handler is allowed to do
215  * this, unless interrupts are disabled.
216  *
217  * Note: we don't check for a full queue, since there aren't enough buffers
218  * to more than fill it.
219  */
220 static void release_arcbuf(struct net_device *dev, int bufnum)
221 {
222 	struct arcnet_local *lp = netdev_priv(dev);
223 	int i;
224 
225 	lp->buf_queue[lp->first_free_buf++] = bufnum;
226 	lp->first_free_buf %= 5;
227 
228 	if (BUGLVL(D_DURING)) {
229 		arc_printk(D_DURING, dev, "release_arcbuf: freed #%d; buffer queue is now: ",
230 			   bufnum);
231 		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
232 			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
233 		arc_cont(D_DURING, "\n");
234 	}
235 }
236 
237 /* Get a buffer from the queue.
238  * If this returns -1, there are no buffers available.
239  */
240 static int get_arcbuf(struct net_device *dev)
241 {
242 	struct arcnet_local *lp = netdev_priv(dev);
243 	int buf = -1, i;
244 
245 	if (!atomic_dec_and_test(&lp->buf_lock)) {
246 		/* already in this function */
247 		arc_printk(D_NORMAL, dev, "get_arcbuf: overlap (%d)!\n",
248 			   lp->buf_lock.counter);
249 	} else {			/* we can continue */
250 		if (lp->next_buf >= 5)
251 			lp->next_buf -= 5;
252 
253 		if (lp->next_buf == lp->first_free_buf) {
254 			arc_printk(D_NORMAL, dev, "get_arcbuf: BUG: no buffers are available??\n");
255 		} else {
256 			buf = lp->buf_queue[lp->next_buf++];
257 			lp->next_buf %= 5;
258 		}
259 	}
260 
261 	if (BUGLVL(D_DURING)) {
262 		arc_printk(D_DURING, dev, "get_arcbuf: got #%d; buffer queue is now: ",
263 			   buf);
264 		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
265 			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
266 		arc_cont(D_DURING, "\n");
267 	}
268 
269 	atomic_inc(&lp->buf_lock);
270 	return buf;
271 }
272 
273 static int choose_mtu(void)
274 {
275 	int count, mtu = 65535;
276 
277 	/* choose the smallest MTU of all available encaps */
278 	for (count = 0; count < 256; count++) {
279 		if (arc_proto_map[count] != &arc_proto_null &&
280 		    arc_proto_map[count]->mtu < mtu) {
281 			mtu = arc_proto_map[count]->mtu;
282 		}
283 	}
284 
285 	return mtu == 65535 ? XMTU : mtu;
286 }
287 
288 static const struct header_ops arcnet_header_ops = {
289 	.create = arcnet_header,
290 };
291 
292 static const struct net_device_ops arcnet_netdev_ops = {
293 	.ndo_open	= arcnet_open,
294 	.ndo_stop	= arcnet_close,
295 	.ndo_start_xmit = arcnet_send_packet,
296 	.ndo_tx_timeout = arcnet_timeout,
297 };
298 
299 /* Setup a struct device for ARCnet. */
300 static void arcdev_setup(struct net_device *dev)
301 {
302 	dev->type = ARPHRD_ARCNET;
303 	dev->netdev_ops = &arcnet_netdev_ops;
304 	dev->header_ops = &arcnet_header_ops;
305 	dev->hard_header_len = sizeof(struct archdr);
306 	dev->mtu = choose_mtu();
307 
308 	dev->addr_len = ARCNET_ALEN;
309 	dev->tx_queue_len = 100;
310 	dev->broadcast[0] = 0x00;	/* for us, broadcasts are address 0 */
311 	dev->watchdog_timeo = TX_TIMEOUT;
312 
313 	/* New-style flags. */
314 	dev->flags = IFF_BROADCAST;
315 }
316 
317 struct net_device *alloc_arcdev(const char *name)
318 {
319 	struct net_device *dev;
320 
321 	dev = alloc_netdev(sizeof(struct arcnet_local),
322 			   name && *name ? name : "arc%d", NET_NAME_UNKNOWN,
323 			   arcdev_setup);
324 	if (dev) {
325 		struct arcnet_local *lp = netdev_priv(dev);
326 
327 		spin_lock_init(&lp->lock);
328 	}
329 
330 	return dev;
331 }
332 EXPORT_SYMBOL(alloc_arcdev);
333 
334 /* Open/initialize the board.  This is called sometime after booting when
335  * the 'ifconfig' program is run.
336  *
337  * This routine should set everything up anew at each open, even registers
338  * that "should" only need to be set once at boot, so that there is
339  * non-reboot way to recover if something goes wrong.
340  */
341 int arcnet_open(struct net_device *dev)
342 {
343 	struct arcnet_local *lp = netdev_priv(dev);
344 	int count, newmtu, error;
345 
346 	arc_printk(D_INIT, dev, "opened.");
347 
348 	if (!try_module_get(lp->hw.owner))
349 		return -ENODEV;
350 
351 	if (BUGLVL(D_PROTO)) {
352 		arc_printk(D_PROTO, dev, "protocol map (default is '%c'): ",
353 			   arc_proto_default->suffix);
354 		for (count = 0; count < 256; count++)
355 			arc_cont(D_PROTO, "%c", arc_proto_map[count]->suffix);
356 		arc_cont(D_PROTO, "\n");
357 	}
358 
359 	arc_printk(D_INIT, dev, "arcnet_open: resetting card.\n");
360 
361 	/* try to put the card in a defined state - if it fails the first
362 	 * time, actually reset it.
363 	 */
364 	error = -ENODEV;
365 	if (lp->hw.reset(dev, 0) && lp->hw.reset(dev, 1))
366 		goto out_module_put;
367 
368 	newmtu = choose_mtu();
369 	if (newmtu < dev->mtu)
370 		dev->mtu = newmtu;
371 
372 	arc_printk(D_INIT, dev, "arcnet_open: mtu: %d.\n", dev->mtu);
373 
374 	/* autodetect the encapsulation for each host. */
375 	memset(lp->default_proto, 0, sizeof(lp->default_proto));
376 
377 	/* the broadcast address is special - use the 'bcast' protocol */
378 	for (count = 0; count < 256; count++) {
379 		if (arc_proto_map[count] == arc_bcast_proto) {
380 			lp->default_proto[0] = count;
381 			break;
382 		}
383 	}
384 
385 	/* initialize buffers */
386 	atomic_set(&lp->buf_lock, 1);
387 
388 	lp->next_buf = lp->first_free_buf = 0;
389 	release_arcbuf(dev, 0);
390 	release_arcbuf(dev, 1);
391 	release_arcbuf(dev, 2);
392 	release_arcbuf(dev, 3);
393 	lp->cur_tx = lp->next_tx = -1;
394 	lp->cur_rx = -1;
395 
396 	lp->rfc1201.sequence = 1;
397 
398 	/* bring up the hardware driver */
399 	if (lp->hw.open)
400 		lp->hw.open(dev);
401 
402 	if (dev->dev_addr[0] == 0)
403 		arc_printk(D_NORMAL, dev, "WARNING!  Station address 00 is reserved for broadcasts!\n");
404 	else if (dev->dev_addr[0] == 255)
405 		arc_printk(D_NORMAL, dev, "WARNING!  Station address FF may confuse DOS networking programs!\n");
406 
407 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
408 	if (lp->hw.status(dev) & RESETflag) {
409 		arc_printk(D_DEBUG, dev, "%s: %d: %s\n",
410 			   __FILE__, __LINE__, __func__);
411 		lp->hw.command(dev, CFLAGScmd | RESETclear);
412 	}
413 
414 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
415 	/* make sure we're ready to receive IRQ's. */
416 	lp->hw.intmask(dev, 0);
417 	udelay(1);		/* give it time to set the mask before
418 				 * we reset it again. (may not even be
419 				 * necessary)
420 				 */
421 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
422 	lp->intmask = NORXflag | RECONflag;
423 	lp->hw.intmask(dev, lp->intmask);
424 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
425 
426 	netif_start_queue(dev);
427 
428 	return 0;
429 
430  out_module_put:
431 	module_put(lp->hw.owner);
432 	return error;
433 }
434 EXPORT_SYMBOL(arcnet_open);
435 
436 /* The inverse routine to arcnet_open - shuts down the card. */
437 int arcnet_close(struct net_device *dev)
438 {
439 	struct arcnet_local *lp = netdev_priv(dev);
440 
441 	netif_stop_queue(dev);
442 
443 	/* flush TX and disable RX */
444 	lp->hw.intmask(dev, 0);
445 	lp->hw.command(dev, NOTXcmd);	/* stop transmit */
446 	lp->hw.command(dev, NORXcmd);	/* disable receive */
447 	mdelay(1);
448 
449 	/* shut down the card */
450 	lp->hw.close(dev);
451 	module_put(lp->hw.owner);
452 	return 0;
453 }
454 EXPORT_SYMBOL(arcnet_close);
455 
456 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
457 			 unsigned short type, const void *daddr,
458 			 const void *saddr, unsigned len)
459 {
460 	const struct arcnet_local *lp = netdev_priv(dev);
461 	uint8_t _daddr, proto_num;
462 	struct ArcProto *proto;
463 
464 	arc_printk(D_DURING, dev,
465 		   "create header from %d to %d; protocol %d (%Xh); size %u.\n",
466 		   saddr ? *(uint8_t *)saddr : -1,
467 		   daddr ? *(uint8_t *)daddr : -1,
468 		   type, type, len);
469 
470 	if (skb->len != 0 && len != skb->len)
471 		arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!\n",
472 			   skb->len, len);
473 
474 	/* Type is host order - ? */
475 	if (type == ETH_P_ARCNET) {
476 		proto = arc_raw_proto;
477 		arc_printk(D_DEBUG, dev, "arc_raw_proto used. proto='%c'\n",
478 			   proto->suffix);
479 		_daddr = daddr ? *(uint8_t *)daddr : 0;
480 	} else if (!daddr) {
481 		/* if the dest addr isn't provided, we can't choose an
482 		 * encapsulation!  Store the packet type (eg. ETH_P_IP)
483 		 * for now, and we'll push on a real header when we do
484 		 * rebuild_header.
485 		 */
486 		*(uint16_t *)skb_push(skb, 2) = type;
487 		/* XXX: Why not use skb->mac_len? */
488 		if (skb->network_header - skb->mac_header != 2)
489 			arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  diff (%u) is not 2!\n",
490 				   skb->network_header - skb->mac_header);
491 		return -2;	/* return error -- can't transmit yet! */
492 	} else {
493 		/* otherwise, we can just add the header as usual. */
494 		_daddr = *(uint8_t *)daddr;
495 		proto_num = lp->default_proto[_daddr];
496 		proto = arc_proto_map[proto_num];
497 		arc_printk(D_DURING, dev, "building header for %02Xh using protocol '%c'\n",
498 			   proto_num, proto->suffix);
499 		if (proto == &arc_proto_null && arc_bcast_proto != proto) {
500 			arc_printk(D_DURING, dev, "actually, let's use '%c' instead.\n",
501 				   arc_bcast_proto->suffix);
502 			proto = arc_bcast_proto;
503 		}
504 	}
505 	return proto->build_header(skb, dev, type, _daddr);
506 }
507 
508 /* Called by the kernel in order to transmit a packet. */
509 netdev_tx_t arcnet_send_packet(struct sk_buff *skb,
510 			       struct net_device *dev)
511 {
512 	struct arcnet_local *lp = netdev_priv(dev);
513 	struct archdr *pkt;
514 	struct arc_rfc1201 *soft;
515 	struct ArcProto *proto;
516 	int txbuf;
517 	unsigned long flags;
518 	int freeskb, retval;
519 
520 	arc_printk(D_DURING, dev,
521 		   "transmit requested (status=%Xh, txbufs=%d/%d, len=%d, protocol %x)\n",
522 		   lp->hw.status(dev), lp->cur_tx, lp->next_tx, skb->len, skb->protocol);
523 
524 	pkt = (struct archdr *)skb->data;
525 	soft = &pkt->soft.rfc1201;
526 	proto = arc_proto_map[soft->proto];
527 
528 	arc_printk(D_SKB_SIZE, dev, "skb: transmitting %d bytes to %02X\n",
529 		   skb->len, pkt->hard.dest);
530 	if (BUGLVL(D_SKB))
531 		arcnet_dump_skb(dev, skb, "tx");
532 
533 	/* fits in one packet? */
534 	if (skb->len - ARC_HDR_SIZE > XMTU && !proto->continue_tx) {
535 		arc_printk(D_NORMAL, dev, "fixme: packet too large: compensating badly!\n");
536 		dev_kfree_skb(skb);
537 		return NETDEV_TX_OK;	/* don't try again */
538 	}
539 
540 	/* We're busy transmitting a packet... */
541 	netif_stop_queue(dev);
542 
543 	spin_lock_irqsave(&lp->lock, flags);
544 	lp->hw.intmask(dev, 0);
545 	if (lp->next_tx == -1)
546 		txbuf = get_arcbuf(dev);
547 	else
548 		txbuf = -1;
549 
550 	if (txbuf != -1) {
551 		if (proto->prepare_tx(dev, pkt, skb->len, txbuf) &&
552 		    !proto->ack_tx) {
553 			/* done right away and we don't want to acknowledge
554 			 *  the package later - forget about it now
555 			 */
556 			dev->stats.tx_bytes += skb->len;
557 			freeskb = 1;
558 		} else {
559 			/* do it the 'split' way */
560 			lp->outgoing.proto = proto;
561 			lp->outgoing.skb = skb;
562 			lp->outgoing.pkt = pkt;
563 
564 			freeskb = 0;
565 
566 			if (proto->continue_tx &&
567 			    proto->continue_tx(dev, txbuf)) {
568 				arc_printk(D_NORMAL, dev,
569 					   "bug! continue_tx finished the first time! (proto='%c')\n",
570 					   proto->suffix);
571 			}
572 		}
573 		retval = NETDEV_TX_OK;
574 		lp->next_tx = txbuf;
575 	} else {
576 		retval = NETDEV_TX_BUSY;
577 		freeskb = 0;
578 	}
579 
580 	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
581 		   __FILE__, __LINE__, __func__, lp->hw.status(dev));
582 	/* make sure we didn't ignore a TX IRQ while we were in here */
583 	lp->hw.intmask(dev, 0);
584 
585 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
586 	lp->intmask |= TXFREEflag | EXCNAKflag;
587 	lp->hw.intmask(dev, lp->intmask);
588 	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
589 		   __FILE__, __LINE__, __func__, lp->hw.status(dev));
590 
591 	spin_unlock_irqrestore(&lp->lock, flags);
592 	if (freeskb)
593 		dev_kfree_skb(skb);
594 
595 	return retval;		/* no need to try again */
596 }
597 EXPORT_SYMBOL(arcnet_send_packet);
598 
599 /* Actually start transmitting a packet that was loaded into a buffer
600  * by prepare_tx.  This should _only_ be called by the interrupt handler.
601  */
602 static int go_tx(struct net_device *dev)
603 {
604 	struct arcnet_local *lp = netdev_priv(dev);
605 
606 	arc_printk(D_DURING, dev, "go_tx: status=%Xh, intmask=%Xh, next_tx=%d, cur_tx=%d\n",
607 		   lp->hw.status(dev), lp->intmask, lp->next_tx, lp->cur_tx);
608 
609 	if (lp->cur_tx != -1 || lp->next_tx == -1)
610 		return 0;
611 
612 	if (BUGLVL(D_TX))
613 		arcnet_dump_packet(dev, lp->next_tx, "go_tx", 0);
614 
615 	lp->cur_tx = lp->next_tx;
616 	lp->next_tx = -1;
617 
618 	/* start sending */
619 	lp->hw.command(dev, TXcmd | (lp->cur_tx << 3));
620 
621 	dev->stats.tx_packets++;
622 	lp->lasttrans_dest = lp->lastload_dest;
623 	lp->lastload_dest = 0;
624 	lp->excnak_pending = 0;
625 	lp->intmask |= TXFREEflag | EXCNAKflag;
626 
627 	return 1;
628 }
629 
630 /* Called by the kernel when transmit times out */
631 void arcnet_timeout(struct net_device *dev)
632 {
633 	unsigned long flags;
634 	struct arcnet_local *lp = netdev_priv(dev);
635 	int status = lp->hw.status(dev);
636 	char *msg;
637 
638 	spin_lock_irqsave(&lp->lock, flags);
639 	if (status & TXFREEflag) {	/* transmit _DID_ finish */
640 		msg = " - missed IRQ?";
641 	} else {
642 		msg = "";
643 		dev->stats.tx_aborted_errors++;
644 		lp->timed_out = 1;
645 		lp->hw.command(dev, NOTXcmd | (lp->cur_tx << 3));
646 	}
647 	dev->stats.tx_errors++;
648 
649 	/* make sure we didn't miss a TX or a EXC NAK IRQ */
650 	lp->hw.intmask(dev, 0);
651 	lp->intmask |= TXFREEflag | EXCNAKflag;
652 	lp->hw.intmask(dev, lp->intmask);
653 
654 	spin_unlock_irqrestore(&lp->lock, flags);
655 
656 	if (time_after(jiffies, lp->last_timeout + 10 * HZ)) {
657 		arc_printk(D_EXTRA, dev, "tx timed out%s (status=%Xh, intmask=%Xh, dest=%02Xh)\n",
658 			   msg, status, lp->intmask, lp->lasttrans_dest);
659 		lp->last_timeout = jiffies;
660 	}
661 
662 	if (lp->cur_tx == -1)
663 		netif_wake_queue(dev);
664 }
665 EXPORT_SYMBOL(arcnet_timeout);
666 
667 /* The typical workload of the driver: Handle the network interface
668  * interrupts. Establish which device needs attention, and call the correct
669  * chipset interrupt handler.
670  */
671 irqreturn_t arcnet_interrupt(int irq, void *dev_id)
672 {
673 	struct net_device *dev = dev_id;
674 	struct arcnet_local *lp;
675 	int recbuf, status, diagstatus, didsomething, boguscount;
676 	int retval = IRQ_NONE;
677 
678 	arc_printk(D_DURING, dev, "\n");
679 
680 	arc_printk(D_DURING, dev, "in arcnet_interrupt\n");
681 
682 	lp = netdev_priv(dev);
683 	BUG_ON(!lp);
684 
685 	spin_lock(&lp->lock);
686 
687 	/* RESET flag was enabled - if device is not running, we must
688 	 * clear it right away (but nothing else).
689 	 */
690 	if (!netif_running(dev)) {
691 		if (lp->hw.status(dev) & RESETflag)
692 			lp->hw.command(dev, CFLAGScmd | RESETclear);
693 		lp->hw.intmask(dev, 0);
694 		spin_unlock(&lp->lock);
695 		return retval;
696 	}
697 
698 	arc_printk(D_DURING, dev, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
699 		   lp->hw.status(dev), lp->intmask);
700 
701 	boguscount = 5;
702 	do {
703 		status = lp->hw.status(dev);
704 		diagstatus = (status >> 8) & 0xFF;
705 
706 		arc_printk(D_DEBUG, dev, "%s: %d: %s: status=%x\n",
707 			   __FILE__, __LINE__, __func__, status);
708 		didsomething = 0;
709 
710 		/* RESET flag was enabled - card is resetting and if RX is
711 		 * disabled, it's NOT because we just got a packet.
712 		 *
713 		 * The card is in an undefined state.
714 		 * Clear it out and start over.
715 		 */
716 		if (status & RESETflag) {
717 			arc_printk(D_NORMAL, dev, "spurious reset (status=%Xh)\n",
718 				   status);
719 			arcnet_close(dev);
720 			arcnet_open(dev);
721 
722 			/* get out of the interrupt handler! */
723 			break;
724 		}
725 		/* RX is inhibited - we must have received something.
726 		 * Prepare to receive into the next buffer.
727 		 *
728 		 * We don't actually copy the received packet from the card
729 		 * until after the transmit handler runs (and possibly
730 		 * launches the next tx); this should improve latency slightly
731 		 * if we get both types of interrupts at once.
732 		 */
733 		recbuf = -1;
734 		if (status & lp->intmask & NORXflag) {
735 			recbuf = lp->cur_rx;
736 			arc_printk(D_DURING, dev, "Buffer #%d: receive irq (status=%Xh)\n",
737 				   recbuf, status);
738 
739 			lp->cur_rx = get_arcbuf(dev);
740 			if (lp->cur_rx != -1) {
741 				arc_printk(D_DURING, dev, "enabling receive to buffer #%d\n",
742 					   lp->cur_rx);
743 				lp->hw.command(dev, RXcmd | (lp->cur_rx << 3) | RXbcasts);
744 			}
745 			didsomething++;
746 		}
747 
748 		if ((diagstatus & EXCNAKflag)) {
749 			arc_printk(D_DURING, dev, "EXCNAK IRQ (diagstat=%Xh)\n",
750 				   diagstatus);
751 
752 			lp->hw.command(dev, NOTXcmd);      /* disable transmit */
753 			lp->excnak_pending = 1;
754 
755 			lp->hw.command(dev, EXCNAKclear);
756 			lp->intmask &= ~(EXCNAKflag);
757 			didsomething++;
758 		}
759 
760 		/* a transmit finished, and we're interested in it. */
761 		if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {
762 			lp->intmask &= ~(TXFREEflag | EXCNAKflag);
763 
764 			arc_printk(D_DURING, dev, "TX IRQ (stat=%Xh)\n",
765 				   status);
766 
767 			if (lp->cur_tx != -1 && !lp->timed_out) {
768 				if (!(status & TXACKflag)) {
769 					if (lp->lasttrans_dest != 0) {
770 						arc_printk(D_EXTRA, dev,
771 							   "transmit was not acknowledged! (status=%Xh, dest=%02Xh)\n",
772 							   status,
773 							   lp->lasttrans_dest);
774 						dev->stats.tx_errors++;
775 						dev->stats.tx_carrier_errors++;
776 					} else {
777 						arc_printk(D_DURING, dev,
778 							   "broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)\n",
779 							   status,
780 							   lp->lasttrans_dest);
781 					}
782 				}
783 
784 				if (lp->outgoing.proto &&
785 				    lp->outgoing.proto->ack_tx) {
786 					int ackstatus;
787 
788 					if (status & TXACKflag)
789 						ackstatus = 2;
790 					else if (lp->excnak_pending)
791 						ackstatus = 1;
792 					else
793 						ackstatus = 0;
794 
795 					lp->outgoing.proto
796 						->ack_tx(dev, ackstatus);
797 				}
798 			}
799 			if (lp->cur_tx != -1)
800 				release_arcbuf(dev, lp->cur_tx);
801 
802 			lp->cur_tx = -1;
803 			lp->timed_out = 0;
804 			didsomething++;
805 
806 			/* send another packet if there is one */
807 			go_tx(dev);
808 
809 			/* continue a split packet, if any */
810 			if (lp->outgoing.proto &&
811 			    lp->outgoing.proto->continue_tx) {
812 				int txbuf = get_arcbuf(dev);
813 
814 				if (txbuf != -1) {
815 					if (lp->outgoing.proto->continue_tx(dev, txbuf)) {
816 						/* that was the last segment */
817 						dev->stats.tx_bytes += lp->outgoing.skb->len;
818 						if (!lp->outgoing.proto->ack_tx) {
819 							dev_kfree_skb_irq(lp->outgoing.skb);
820 							lp->outgoing.proto = NULL;
821 						}
822 					}
823 					lp->next_tx = txbuf;
824 				}
825 			}
826 			/* inform upper layers of idleness, if necessary */
827 			if (lp->cur_tx == -1)
828 				netif_wake_queue(dev);
829 		}
830 		/* now process the received packet, if any */
831 		if (recbuf != -1) {
832 			if (BUGLVL(D_RX))
833 				arcnet_dump_packet(dev, recbuf, "rx irq", 0);
834 
835 			arcnet_rx(dev, recbuf);
836 			release_arcbuf(dev, recbuf);
837 
838 			didsomething++;
839 		}
840 		if (status & lp->intmask & RECONflag) {
841 			lp->hw.command(dev, CFLAGScmd | CONFIGclear);
842 			dev->stats.tx_carrier_errors++;
843 
844 			arc_printk(D_RECON, dev, "Network reconfiguration detected (status=%Xh)\n",
845 				   status);
846 			/* MYRECON bit is at bit 7 of diagstatus */
847 			if (diagstatus & 0x80)
848 				arc_printk(D_RECON, dev, "Put out that recon myself\n");
849 
850 			/* is the RECON info empty or old? */
851 			if (!lp->first_recon || !lp->last_recon ||
852 			    time_after(jiffies, lp->last_recon + HZ * 10)) {
853 				if (lp->network_down)
854 					arc_printk(D_NORMAL, dev, "reconfiguration detected: cabling restored?\n");
855 				lp->first_recon = lp->last_recon = jiffies;
856 				lp->num_recons = lp->network_down = 0;
857 
858 				arc_printk(D_DURING, dev, "recon: clearing counters.\n");
859 			} else {	/* add to current RECON counter */
860 				lp->last_recon = jiffies;
861 				lp->num_recons++;
862 
863 				arc_printk(D_DURING, dev, "recon: counter=%d, time=%lds, net=%d\n",
864 					   lp->num_recons,
865 					   (lp->last_recon - lp->first_recon) / HZ,
866 					   lp->network_down);
867 
868 				/* if network is marked up;
869 				 * and first_recon and last_recon are 60+ apart;
870 				 * and the average no. of recons counted is
871 				 *    > RECON_THRESHOLD/min;
872 				 * then print a warning message.
873 				 */
874 				if (!lp->network_down &&
875 				    (lp->last_recon - lp->first_recon) <= HZ * 60 &&
876 				    lp->num_recons >= RECON_THRESHOLD) {
877 					lp->network_down = 1;
878 					arc_printk(D_NORMAL, dev, "many reconfigurations detected: cabling problem?\n");
879 				} else if (!lp->network_down &&
880 					   lp->last_recon - lp->first_recon > HZ * 60) {
881 					/* reset counters if we've gone for
882 					 *  over a minute.
883 					 */
884 					lp->first_recon = lp->last_recon;
885 					lp->num_recons = 1;
886 				}
887 			}
888 		} else if (lp->network_down &&
889 			   time_after(jiffies, lp->last_recon + HZ * 10)) {
890 			if (lp->network_down)
891 				arc_printk(D_NORMAL, dev, "cabling restored?\n");
892 			lp->first_recon = lp->last_recon = 0;
893 			lp->num_recons = lp->network_down = 0;
894 
895 			arc_printk(D_DURING, dev, "not recon: clearing counters anyway.\n");
896 		}
897 
898 		if (didsomething)
899 			retval |= IRQ_HANDLED;
900 	} while (--boguscount && didsomething);
901 
902 	arc_printk(D_DURING, dev, "arcnet_interrupt complete (status=%Xh, count=%d)\n",
903 		   lp->hw.status(dev), boguscount);
904 	arc_printk(D_DURING, dev, "\n");
905 
906 	lp->hw.intmask(dev, 0);
907 	udelay(1);
908 	lp->hw.intmask(dev, lp->intmask);
909 
910 	spin_unlock(&lp->lock);
911 	return retval;
912 }
913 EXPORT_SYMBOL(arcnet_interrupt);
914 
915 /* This is a generic packet receiver that calls arcnet??_rx depending on the
916  * protocol ID found.
917  */
918 static void arcnet_rx(struct net_device *dev, int bufnum)
919 {
920 	struct arcnet_local *lp = netdev_priv(dev);
921 	struct archdr pkt;
922 	struct arc_rfc1201 *soft;
923 	int length, ofs;
924 
925 	soft = &pkt.soft.rfc1201;
926 
927 	lp->hw.copy_from_card(dev, bufnum, 0, &pkt, ARC_HDR_SIZE);
928 	if (pkt.hard.offset[0]) {
929 		ofs = pkt.hard.offset[0];
930 		length = 256 - ofs;
931 	} else {
932 		ofs = pkt.hard.offset[1];
933 		length = 512 - ofs;
934 	}
935 
936 	/* get the full header, if possible */
937 	if (sizeof(pkt.soft) <= length) {
938 		lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(pkt.soft));
939 	} else {
940 		memset(&pkt.soft, 0, sizeof(pkt.soft));
941 		lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
942 	}
943 
944 	arc_printk(D_DURING, dev, "Buffer #%d: received packet from %02Xh to %02Xh (%d+4 bytes)\n",
945 		   bufnum, pkt.hard.source, pkt.hard.dest, length);
946 
947 	dev->stats.rx_packets++;
948 	dev->stats.rx_bytes += length + ARC_HDR_SIZE;
949 
950 	/* call the right receiver for the protocol */
951 	if (arc_proto_map[soft->proto]->is_ip) {
952 		if (BUGLVL(D_PROTO)) {
953 			struct ArcProto
954 			*oldp = arc_proto_map[lp->default_proto[pkt.hard.source]],
955 			*newp = arc_proto_map[soft->proto];
956 
957 			if (oldp != newp) {
958 				arc_printk(D_PROTO, dev,
959 					   "got protocol %02Xh; encap for host %02Xh is now '%c' (was '%c')\n",
960 					   soft->proto, pkt.hard.source,
961 					   newp->suffix, oldp->suffix);
962 			}
963 		}
964 
965 		/* broadcasts will always be done with the last-used encap. */
966 		lp->default_proto[0] = soft->proto;
967 
968 		/* in striking contrast, the following isn't a hack. */
969 		lp->default_proto[pkt.hard.source] = soft->proto;
970 	}
971 	/* call the protocol-specific receiver. */
972 	arc_proto_map[soft->proto]->rx(dev, bufnum, &pkt, length);
973 }
974 
975 static void null_rx(struct net_device *dev, int bufnum,
976 		    struct archdr *pkthdr, int length)
977 {
978 	arc_printk(D_PROTO, dev,
979 		   "rx: don't know how to deal with proto %02Xh from host %02Xh.\n",
980 		   pkthdr->soft.rfc1201.proto, pkthdr->hard.source);
981 }
982 
983 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
984 			     unsigned short type, uint8_t daddr)
985 {
986 	struct arcnet_local *lp = netdev_priv(dev);
987 
988 	arc_printk(D_PROTO, dev,
989 		   "tx: can't build header for encap %02Xh; load a protocol driver.\n",
990 		   lp->default_proto[daddr]);
991 
992 	/* always fails */
993 	return 0;
994 }
995 
996 /* the "do nothing" prepare_tx function warns that there's nothing to do. */
997 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
998 			   int length, int bufnum)
999 {
1000 	struct arcnet_local *lp = netdev_priv(dev);
1001 	struct arc_hardware newpkt;
1002 
1003 	arc_printk(D_PROTO, dev, "tx: no encap for this host; load a protocol driver.\n");
1004 
1005 	/* send a packet to myself -- will never get received, of course */
1006 	newpkt.source = newpkt.dest = dev->dev_addr[0];
1007 
1008 	/* only one byte of actual data (and it's random) */
1009 	newpkt.offset[0] = 0xFF;
1010 
1011 	lp->hw.copy_to_card(dev, bufnum, 0, &newpkt, ARC_HDR_SIZE);
1012 
1013 	return 1;		/* done */
1014 }
1015