xref: /openbmc/linux/drivers/net/arcnet/arcnet.c (revision 5d0e4d78)
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 #include <linux/errqueue.h>
55 
56 #include <linux/leds.h>
57 
58 #include "arcdevice.h"
59 #include "com9026.h"
60 
61 /* "do nothing" functions for protocol drivers */
62 static void null_rx(struct net_device *dev, int bufnum,
63 		    struct archdr *pkthdr, int length);
64 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
65 			     unsigned short type, uint8_t daddr);
66 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
67 			   int length, int bufnum);
68 
69 static void arcnet_rx(struct net_device *dev, int bufnum);
70 
71 /* one ArcProto per possible proto ID.  None of the elements of
72  * arc_proto_map are allowed to be NULL; they will get set to
73  * arc_proto_default instead.  It also must not be NULL; if you would like
74  * to set it to NULL, set it to &arc_proto_null instead.
75  */
76 struct ArcProto *arc_proto_map[256];
77 EXPORT_SYMBOL(arc_proto_map);
78 
79 struct ArcProto *arc_proto_default;
80 EXPORT_SYMBOL(arc_proto_default);
81 
82 struct ArcProto *arc_bcast_proto;
83 EXPORT_SYMBOL(arc_bcast_proto);
84 
85 struct ArcProto *arc_raw_proto;
86 EXPORT_SYMBOL(arc_raw_proto);
87 
88 static struct ArcProto arc_proto_null = {
89 	.suffix		= '?',
90 	.mtu		= XMTU,
91 	.is_ip          = 0,
92 	.rx		= null_rx,
93 	.build_header	= null_build_header,
94 	.prepare_tx	= null_prepare_tx,
95 	.continue_tx    = NULL,
96 	.ack_tx         = NULL
97 };
98 
99 /* Exported function prototypes */
100 int arcnet_debug = ARCNET_DEBUG;
101 EXPORT_SYMBOL(arcnet_debug);
102 
103 /* Internal function prototypes */
104 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
105 			 unsigned short type, const void *daddr,
106 			 const void *saddr, unsigned len);
107 static int go_tx(struct net_device *dev);
108 
109 static int debug = ARCNET_DEBUG;
110 module_param(debug, int, 0);
111 MODULE_LICENSE("GPL");
112 
113 static int __init arcnet_init(void)
114 {
115 	int count;
116 
117 	arcnet_debug = debug;
118 
119 	pr_info("arcnet loaded\n");
120 
121 	/* initialize the protocol map */
122 	arc_raw_proto = arc_proto_default = arc_bcast_proto = &arc_proto_null;
123 	for (count = 0; count < 256; count++)
124 		arc_proto_map[count] = arc_proto_default;
125 
126 	if (BUGLVL(D_DURING))
127 		pr_info("struct sizes: %zd %zd %zd %zd %zd\n",
128 			sizeof(struct arc_hardware),
129 			sizeof(struct arc_rfc1201),
130 			sizeof(struct arc_rfc1051),
131 			sizeof(struct arc_eth_encap),
132 			sizeof(struct archdr));
133 
134 	return 0;
135 }
136 
137 static void __exit arcnet_exit(void)
138 {
139 }
140 
141 module_init(arcnet_init);
142 module_exit(arcnet_exit);
143 
144 /* Dump the contents of an sk_buff */
145 #if ARCNET_DEBUG_MAX & D_SKB
146 void arcnet_dump_skb(struct net_device *dev,
147 		     struct sk_buff *skb, char *desc)
148 {
149 	char hdr[32];
150 
151 	/* dump the packet */
152 	snprintf(hdr, sizeof(hdr), "%6s:%s skb->data:", dev->name, desc);
153 	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
154 		       16, 1, skb->data, skb->len, true);
155 }
156 EXPORT_SYMBOL(arcnet_dump_skb);
157 #endif
158 
159 /* Dump the contents of an ARCnet buffer */
160 #if (ARCNET_DEBUG_MAX & (D_RX | D_TX))
161 static void arcnet_dump_packet(struct net_device *dev, int bufnum,
162 			       char *desc, int take_arcnet_lock)
163 {
164 	struct arcnet_local *lp = netdev_priv(dev);
165 	int i, length;
166 	unsigned long flags = 0;
167 	static uint8_t buf[512];
168 	char hdr[32];
169 
170 	/* hw.copy_from_card expects IRQ context so take the IRQ lock
171 	 * to keep it single threaded
172 	 */
173 	if (take_arcnet_lock)
174 		spin_lock_irqsave(&lp->lock, flags);
175 
176 	lp->hw.copy_from_card(dev, bufnum, 0, buf, 512);
177 	if (take_arcnet_lock)
178 		spin_unlock_irqrestore(&lp->lock, flags);
179 
180 	/* if the offset[0] byte is nonzero, this is a 256-byte packet */
181 	length = (buf[2] ? 256 : 512);
182 
183 	/* dump the packet */
184 	snprintf(hdr, sizeof(hdr), "%6s:%s packet dump:", dev->name, desc);
185 	print_hex_dump(KERN_DEBUG, hdr, DUMP_PREFIX_OFFSET,
186 		       16, 1, buf, length, true);
187 }
188 
189 #else
190 
191 #define arcnet_dump_packet(dev, bufnum, desc, take_arcnet_lock) do { } while (0)
192 
193 #endif
194 
195 /* Trigger a LED event in response to a ARCNET device event */
196 void arcnet_led_event(struct net_device *dev, enum arcnet_led_event event)
197 {
198 	struct arcnet_local *lp = netdev_priv(dev);
199 	unsigned long led_delay = 350;
200 	unsigned long tx_delay = 50;
201 
202 	switch (event) {
203 	case ARCNET_LED_EVENT_RECON:
204 		led_trigger_blink_oneshot(lp->recon_led_trig,
205 					  &led_delay, &led_delay, 0);
206 		break;
207 	case ARCNET_LED_EVENT_OPEN:
208 		led_trigger_event(lp->tx_led_trig, LED_OFF);
209 		led_trigger_event(lp->recon_led_trig, LED_OFF);
210 		break;
211 	case ARCNET_LED_EVENT_STOP:
212 		led_trigger_event(lp->tx_led_trig, LED_OFF);
213 		led_trigger_event(lp->recon_led_trig, LED_OFF);
214 		break;
215 	case ARCNET_LED_EVENT_TX:
216 		led_trigger_blink_oneshot(lp->tx_led_trig,
217 					  &tx_delay, &tx_delay, 0);
218 		break;
219 	}
220 }
221 EXPORT_SYMBOL_GPL(arcnet_led_event);
222 
223 static void arcnet_led_release(struct device *gendev, void *res)
224 {
225 	struct arcnet_local *lp = netdev_priv(to_net_dev(gendev));
226 
227 	led_trigger_unregister_simple(lp->tx_led_trig);
228 	led_trigger_unregister_simple(lp->recon_led_trig);
229 }
230 
231 /* Register ARCNET LED triggers for a arcnet device
232  *
233  * This is normally called from a driver's probe function
234  */
235 void devm_arcnet_led_init(struct net_device *netdev, int index, int subid)
236 {
237 	struct arcnet_local *lp = netdev_priv(netdev);
238 	void *res;
239 
240 	res = devres_alloc(arcnet_led_release, 0, GFP_KERNEL);
241 	if (!res) {
242 		netdev_err(netdev, "cannot register LED triggers\n");
243 		return;
244 	}
245 
246 	snprintf(lp->tx_led_trig_name, sizeof(lp->tx_led_trig_name),
247 		 "arc%d-%d-tx", index, subid);
248 	snprintf(lp->recon_led_trig_name, sizeof(lp->recon_led_trig_name),
249 		 "arc%d-%d-recon", index, subid);
250 
251 	led_trigger_register_simple(lp->tx_led_trig_name,
252 				    &lp->tx_led_trig);
253 	led_trigger_register_simple(lp->recon_led_trig_name,
254 				    &lp->recon_led_trig);
255 
256 	devres_add(&netdev->dev, res);
257 }
258 EXPORT_SYMBOL_GPL(devm_arcnet_led_init);
259 
260 /* Unregister a protocol driver from the arc_proto_map.  Protocol drivers
261  * are responsible for registering themselves, but the unregister routine
262  * is pretty generic so we'll do it here.
263  */
264 void arcnet_unregister_proto(struct ArcProto *proto)
265 {
266 	int count;
267 
268 	if (arc_proto_default == proto)
269 		arc_proto_default = &arc_proto_null;
270 	if (arc_bcast_proto == proto)
271 		arc_bcast_proto = arc_proto_default;
272 	if (arc_raw_proto == proto)
273 		arc_raw_proto = arc_proto_default;
274 
275 	for (count = 0; count < 256; count++) {
276 		if (arc_proto_map[count] == proto)
277 			arc_proto_map[count] = arc_proto_default;
278 	}
279 }
280 EXPORT_SYMBOL(arcnet_unregister_proto);
281 
282 /* Add a buffer to the queue.  Only the interrupt handler is allowed to do
283  * this, unless interrupts are disabled.
284  *
285  * Note: we don't check for a full queue, since there aren't enough buffers
286  * to more than fill it.
287  */
288 static void release_arcbuf(struct net_device *dev, int bufnum)
289 {
290 	struct arcnet_local *lp = netdev_priv(dev);
291 	int i;
292 
293 	lp->buf_queue[lp->first_free_buf++] = bufnum;
294 	lp->first_free_buf %= 5;
295 
296 	if (BUGLVL(D_DURING)) {
297 		arc_printk(D_DURING, dev, "release_arcbuf: freed #%d; buffer queue is now: ",
298 			   bufnum);
299 		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
300 			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
301 		arc_cont(D_DURING, "\n");
302 	}
303 }
304 
305 /* Get a buffer from the queue.
306  * If this returns -1, there are no buffers available.
307  */
308 static int get_arcbuf(struct net_device *dev)
309 {
310 	struct arcnet_local *lp = netdev_priv(dev);
311 	int buf = -1, i;
312 
313 	if (!atomic_dec_and_test(&lp->buf_lock)) {
314 		/* already in this function */
315 		arc_printk(D_NORMAL, dev, "get_arcbuf: overlap (%d)!\n",
316 			   lp->buf_lock.counter);
317 	} else {			/* we can continue */
318 		if (lp->next_buf >= 5)
319 			lp->next_buf -= 5;
320 
321 		if (lp->next_buf == lp->first_free_buf) {
322 			arc_printk(D_NORMAL, dev, "get_arcbuf: BUG: no buffers are available??\n");
323 		} else {
324 			buf = lp->buf_queue[lp->next_buf++];
325 			lp->next_buf %= 5;
326 		}
327 	}
328 
329 	if (BUGLVL(D_DURING)) {
330 		arc_printk(D_DURING, dev, "get_arcbuf: got #%d; buffer queue is now: ",
331 			   buf);
332 		for (i = lp->next_buf; i != lp->first_free_buf; i = (i + 1) % 5)
333 			arc_cont(D_DURING, "#%d ", lp->buf_queue[i]);
334 		arc_cont(D_DURING, "\n");
335 	}
336 
337 	atomic_inc(&lp->buf_lock);
338 	return buf;
339 }
340 
341 static int choose_mtu(void)
342 {
343 	int count, mtu = 65535;
344 
345 	/* choose the smallest MTU of all available encaps */
346 	for (count = 0; count < 256; count++) {
347 		if (arc_proto_map[count] != &arc_proto_null &&
348 		    arc_proto_map[count]->mtu < mtu) {
349 			mtu = arc_proto_map[count]->mtu;
350 		}
351 	}
352 
353 	return mtu == 65535 ? XMTU : mtu;
354 }
355 
356 static const struct header_ops arcnet_header_ops = {
357 	.create = arcnet_header,
358 };
359 
360 static const struct net_device_ops arcnet_netdev_ops = {
361 	.ndo_open	= arcnet_open,
362 	.ndo_stop	= arcnet_close,
363 	.ndo_start_xmit = arcnet_send_packet,
364 	.ndo_tx_timeout = arcnet_timeout,
365 };
366 
367 /* Setup a struct device for ARCnet. */
368 static void arcdev_setup(struct net_device *dev)
369 {
370 	dev->type = ARPHRD_ARCNET;
371 	dev->netdev_ops = &arcnet_netdev_ops;
372 	dev->header_ops = &arcnet_header_ops;
373 	dev->hard_header_len = sizeof(struct arc_hardware);
374 	dev->mtu = choose_mtu();
375 
376 	dev->addr_len = ARCNET_ALEN;
377 	dev->tx_queue_len = 100;
378 	dev->broadcast[0] = 0x00;	/* for us, broadcasts are address 0 */
379 	dev->watchdog_timeo = TX_TIMEOUT;
380 
381 	/* New-style flags. */
382 	dev->flags = IFF_BROADCAST;
383 }
384 
385 static void arcnet_timer(unsigned long data)
386 {
387 	struct net_device *dev = (struct net_device *)data;
388 
389 	if (!netif_carrier_ok(dev)) {
390 		netif_carrier_on(dev);
391 		netdev_info(dev, "link up\n");
392 	}
393 }
394 
395 static void arcnet_reply_tasklet(unsigned long data)
396 {
397 	struct arcnet_local *lp = (struct arcnet_local *)data;
398 
399 	struct sk_buff *ackskb, *skb;
400 	struct sock_exterr_skb *serr;
401 	struct sock *sk;
402 	int ret;
403 
404 	local_irq_disable();
405 	skb = lp->outgoing.skb;
406 	if (!skb || !skb->sk) {
407 		local_irq_enable();
408 		return;
409 	}
410 
411 	sock_hold(skb->sk);
412 	sk = skb->sk;
413 	ackskb = skb_clone_sk(skb);
414 	sock_put(skb->sk);
415 
416 	if (!ackskb) {
417 		local_irq_enable();
418 		return;
419 	}
420 
421 	serr = SKB_EXT_ERR(ackskb);
422 	memset(serr, 0, sizeof(*serr));
423 	serr->ee.ee_errno = ENOMSG;
424 	serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS;
425 	serr->ee.ee_data = skb_shinfo(skb)->tskey;
426 	serr->ee.ee_info = lp->reply_status;
427 
428 	/* finally erasing outgoing skb */
429 	dev_kfree_skb(lp->outgoing.skb);
430 	lp->outgoing.skb = NULL;
431 
432 	ackskb->dev = lp->dev;
433 
434 	ret = sock_queue_err_skb(sk, ackskb);
435 	if (ret)
436 		kfree_skb(ackskb);
437 
438 	local_irq_enable();
439 };
440 
441 struct net_device *alloc_arcdev(const char *name)
442 {
443 	struct net_device *dev;
444 
445 	dev = alloc_netdev(sizeof(struct arcnet_local),
446 			   name && *name ? name : "arc%d", NET_NAME_UNKNOWN,
447 			   arcdev_setup);
448 	if (dev) {
449 		struct arcnet_local *lp = netdev_priv(dev);
450 
451 		lp->dev = dev;
452 		spin_lock_init(&lp->lock);
453 		init_timer(&lp->timer);
454 		lp->timer.data = (unsigned long) dev;
455 		lp->timer.function = arcnet_timer;
456 	}
457 
458 	return dev;
459 }
460 EXPORT_SYMBOL(alloc_arcdev);
461 
462 /* Open/initialize the board.  This is called sometime after booting when
463  * the 'ifconfig' program is run.
464  *
465  * This routine should set everything up anew at each open, even registers
466  * that "should" only need to be set once at boot, so that there is
467  * non-reboot way to recover if something goes wrong.
468  */
469 int arcnet_open(struct net_device *dev)
470 {
471 	struct arcnet_local *lp = netdev_priv(dev);
472 	int count, newmtu, error;
473 
474 	arc_printk(D_INIT, dev, "opened.");
475 
476 	if (!try_module_get(lp->hw.owner))
477 		return -ENODEV;
478 
479 	if (BUGLVL(D_PROTO)) {
480 		arc_printk(D_PROTO, dev, "protocol map (default is '%c'): ",
481 			   arc_proto_default->suffix);
482 		for (count = 0; count < 256; count++)
483 			arc_cont(D_PROTO, "%c", arc_proto_map[count]->suffix);
484 		arc_cont(D_PROTO, "\n");
485 	}
486 
487 	tasklet_init(&lp->reply_tasklet, arcnet_reply_tasklet,
488 		     (unsigned long)lp);
489 
490 	arc_printk(D_INIT, dev, "arcnet_open: resetting card.\n");
491 
492 	/* try to put the card in a defined state - if it fails the first
493 	 * time, actually reset it.
494 	 */
495 	error = -ENODEV;
496 	if (lp->hw.reset(dev, 0) && lp->hw.reset(dev, 1))
497 		goto out_module_put;
498 
499 	newmtu = choose_mtu();
500 	if (newmtu < dev->mtu)
501 		dev->mtu = newmtu;
502 
503 	arc_printk(D_INIT, dev, "arcnet_open: mtu: %d.\n", dev->mtu);
504 
505 	/* autodetect the encapsulation for each host. */
506 	memset(lp->default_proto, 0, sizeof(lp->default_proto));
507 
508 	/* the broadcast address is special - use the 'bcast' protocol */
509 	for (count = 0; count < 256; count++) {
510 		if (arc_proto_map[count] == arc_bcast_proto) {
511 			lp->default_proto[0] = count;
512 			break;
513 		}
514 	}
515 
516 	/* initialize buffers */
517 	atomic_set(&lp->buf_lock, 1);
518 
519 	lp->next_buf = lp->first_free_buf = 0;
520 	release_arcbuf(dev, 0);
521 	release_arcbuf(dev, 1);
522 	release_arcbuf(dev, 2);
523 	release_arcbuf(dev, 3);
524 	lp->cur_tx = lp->next_tx = -1;
525 	lp->cur_rx = -1;
526 
527 	lp->rfc1201.sequence = 1;
528 
529 	/* bring up the hardware driver */
530 	if (lp->hw.open)
531 		lp->hw.open(dev);
532 
533 	if (dev->dev_addr[0] == 0)
534 		arc_printk(D_NORMAL, dev, "WARNING!  Station address 00 is reserved for broadcasts!\n");
535 	else if (dev->dev_addr[0] == 255)
536 		arc_printk(D_NORMAL, dev, "WARNING!  Station address FF may confuse DOS networking programs!\n");
537 
538 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
539 	if (lp->hw.status(dev) & RESETflag) {
540 		arc_printk(D_DEBUG, dev, "%s: %d: %s\n",
541 			   __FILE__, __LINE__, __func__);
542 		lp->hw.command(dev, CFLAGScmd | RESETclear);
543 	}
544 
545 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
546 	/* make sure we're ready to receive IRQ's. */
547 	lp->hw.intmask(dev, 0);
548 	udelay(1);		/* give it time to set the mask before
549 				 * we reset it again. (may not even be
550 				 * necessary)
551 				 */
552 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
553 	lp->intmask = NORXflag | RECONflag;
554 	lp->hw.intmask(dev, lp->intmask);
555 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
556 
557 	netif_carrier_off(dev);
558 	netif_start_queue(dev);
559 	mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
560 
561 	arcnet_led_event(dev, ARCNET_LED_EVENT_OPEN);
562 	return 0;
563 
564  out_module_put:
565 	module_put(lp->hw.owner);
566 	return error;
567 }
568 EXPORT_SYMBOL(arcnet_open);
569 
570 /* The inverse routine to arcnet_open - shuts down the card. */
571 int arcnet_close(struct net_device *dev)
572 {
573 	struct arcnet_local *lp = netdev_priv(dev);
574 
575 	arcnet_led_event(dev, ARCNET_LED_EVENT_STOP);
576 	del_timer_sync(&lp->timer);
577 
578 	netif_stop_queue(dev);
579 	netif_carrier_off(dev);
580 
581 	tasklet_kill(&lp->reply_tasklet);
582 
583 	/* flush TX and disable RX */
584 	lp->hw.intmask(dev, 0);
585 	lp->hw.command(dev, NOTXcmd);	/* stop transmit */
586 	lp->hw.command(dev, NORXcmd);	/* disable receive */
587 	mdelay(1);
588 
589 	/* shut down the card */
590 	lp->hw.close(dev);
591 	module_put(lp->hw.owner);
592 	return 0;
593 }
594 EXPORT_SYMBOL(arcnet_close);
595 
596 static int arcnet_header(struct sk_buff *skb, struct net_device *dev,
597 			 unsigned short type, const void *daddr,
598 			 const void *saddr, unsigned len)
599 {
600 	const struct arcnet_local *lp = netdev_priv(dev);
601 	uint8_t _daddr, proto_num;
602 	struct ArcProto *proto;
603 
604 	arc_printk(D_DURING, dev,
605 		   "create header from %d to %d; protocol %d (%Xh); size %u.\n",
606 		   saddr ? *(uint8_t *)saddr : -1,
607 		   daddr ? *(uint8_t *)daddr : -1,
608 		   type, type, len);
609 
610 	if (skb->len != 0 && len != skb->len)
611 		arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  skb->len(%d) != len(%d)!\n",
612 			   skb->len, len);
613 
614 	/* Type is host order - ? */
615 	if (type == ETH_P_ARCNET) {
616 		proto = arc_raw_proto;
617 		arc_printk(D_DEBUG, dev, "arc_raw_proto used. proto='%c'\n",
618 			   proto->suffix);
619 		_daddr = daddr ? *(uint8_t *)daddr : 0;
620 	} else if (!daddr) {
621 		/* if the dest addr isn't provided, we can't choose an
622 		 * encapsulation!  Store the packet type (eg. ETH_P_IP)
623 		 * for now, and we'll push on a real header when we do
624 		 * rebuild_header.
625 		 */
626 		*(uint16_t *)skb_push(skb, 2) = type;
627 		/* XXX: Why not use skb->mac_len? */
628 		if (skb->network_header - skb->mac_header != 2)
629 			arc_printk(D_NORMAL, dev, "arcnet_header: Yikes!  diff (%u) is not 2!\n",
630 				   skb->network_header - skb->mac_header);
631 		return -2;	/* return error -- can't transmit yet! */
632 	} else {
633 		/* otherwise, we can just add the header as usual. */
634 		_daddr = *(uint8_t *)daddr;
635 		proto_num = lp->default_proto[_daddr];
636 		proto = arc_proto_map[proto_num];
637 		arc_printk(D_DURING, dev, "building header for %02Xh using protocol '%c'\n",
638 			   proto_num, proto->suffix);
639 		if (proto == &arc_proto_null && arc_bcast_proto != proto) {
640 			arc_printk(D_DURING, dev, "actually, let's use '%c' instead.\n",
641 				   arc_bcast_proto->suffix);
642 			proto = arc_bcast_proto;
643 		}
644 	}
645 	return proto->build_header(skb, dev, type, _daddr);
646 }
647 
648 /* Called by the kernel in order to transmit a packet. */
649 netdev_tx_t arcnet_send_packet(struct sk_buff *skb,
650 			       struct net_device *dev)
651 {
652 	struct arcnet_local *lp = netdev_priv(dev);
653 	struct archdr *pkt;
654 	struct arc_rfc1201 *soft;
655 	struct ArcProto *proto;
656 	int txbuf;
657 	unsigned long flags;
658 	int retval;
659 
660 	arc_printk(D_DURING, dev,
661 		   "transmit requested (status=%Xh, txbufs=%d/%d, len=%d, protocol %x)\n",
662 		   lp->hw.status(dev), lp->cur_tx, lp->next_tx, skb->len, skb->protocol);
663 
664 	pkt = (struct archdr *)skb->data;
665 	soft = &pkt->soft.rfc1201;
666 	proto = arc_proto_map[soft->proto];
667 
668 	arc_printk(D_SKB_SIZE, dev, "skb: transmitting %d bytes to %02X\n",
669 		   skb->len, pkt->hard.dest);
670 	if (BUGLVL(D_SKB))
671 		arcnet_dump_skb(dev, skb, "tx");
672 
673 	/* fits in one packet? */
674 	if (skb->len - ARC_HDR_SIZE > XMTU && !proto->continue_tx) {
675 		arc_printk(D_NORMAL, dev, "fixme: packet too large: compensating badly!\n");
676 		dev_kfree_skb(skb);
677 		return NETDEV_TX_OK;	/* don't try again */
678 	}
679 
680 	/* We're busy transmitting a packet... */
681 	netif_stop_queue(dev);
682 
683 	spin_lock_irqsave(&lp->lock, flags);
684 	lp->hw.intmask(dev, 0);
685 	if (lp->next_tx == -1)
686 		txbuf = get_arcbuf(dev);
687 	else
688 		txbuf = -1;
689 
690 	if (txbuf != -1) {
691 		lp->outgoing.skb = skb;
692 		if (proto->prepare_tx(dev, pkt, skb->len, txbuf) &&
693 		    !proto->ack_tx) {
694 			/* done right away and we don't want to acknowledge
695 			 *  the package later - forget about it now
696 			 */
697 			dev->stats.tx_bytes += skb->len;
698 		} else {
699 			/* do it the 'split' way */
700 			lp->outgoing.proto = proto;
701 			lp->outgoing.skb = skb;
702 			lp->outgoing.pkt = pkt;
703 
704 			if (proto->continue_tx &&
705 			    proto->continue_tx(dev, txbuf)) {
706 				arc_printk(D_NORMAL, dev,
707 					   "bug! continue_tx finished the first time! (proto='%c')\n",
708 					   proto->suffix);
709 			}
710 		}
711 		retval = NETDEV_TX_OK;
712 		lp->next_tx = txbuf;
713 	} else {
714 		retval = NETDEV_TX_BUSY;
715 	}
716 
717 	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
718 		   __FILE__, __LINE__, __func__, lp->hw.status(dev));
719 	/* make sure we didn't ignore a TX IRQ while we were in here */
720 	lp->hw.intmask(dev, 0);
721 
722 	arc_printk(D_DEBUG, dev, "%s: %d: %s\n", __FILE__, __LINE__, __func__);
723 	lp->intmask |= TXFREEflag | EXCNAKflag;
724 	lp->hw.intmask(dev, lp->intmask);
725 	arc_printk(D_DEBUG, dev, "%s: %d: %s, status: %x\n",
726 		   __FILE__, __LINE__, __func__, lp->hw.status(dev));
727 
728 	arcnet_led_event(dev, ARCNET_LED_EVENT_TX);
729 
730 	spin_unlock_irqrestore(&lp->lock, flags);
731 	return retval;		/* no need to try again */
732 }
733 EXPORT_SYMBOL(arcnet_send_packet);
734 
735 /* Actually start transmitting a packet that was loaded into a buffer
736  * by prepare_tx.  This should _only_ be called by the interrupt handler.
737  */
738 static int go_tx(struct net_device *dev)
739 {
740 	struct arcnet_local *lp = netdev_priv(dev);
741 
742 	arc_printk(D_DURING, dev, "go_tx: status=%Xh, intmask=%Xh, next_tx=%d, cur_tx=%d\n",
743 		   lp->hw.status(dev), lp->intmask, lp->next_tx, lp->cur_tx);
744 
745 	if (lp->cur_tx != -1 || lp->next_tx == -1)
746 		return 0;
747 
748 	if (BUGLVL(D_TX))
749 		arcnet_dump_packet(dev, lp->next_tx, "go_tx", 0);
750 
751 	lp->cur_tx = lp->next_tx;
752 	lp->next_tx = -1;
753 
754 	/* start sending */
755 	lp->hw.command(dev, TXcmd | (lp->cur_tx << 3));
756 
757 	dev->stats.tx_packets++;
758 	lp->lasttrans_dest = lp->lastload_dest;
759 	lp->lastload_dest = 0;
760 	lp->excnak_pending = 0;
761 	lp->intmask |= TXFREEflag | EXCNAKflag;
762 
763 	return 1;
764 }
765 
766 /* Called by the kernel when transmit times out */
767 void arcnet_timeout(struct net_device *dev)
768 {
769 	unsigned long flags;
770 	struct arcnet_local *lp = netdev_priv(dev);
771 	int status = lp->hw.status(dev);
772 	char *msg;
773 
774 	spin_lock_irqsave(&lp->lock, flags);
775 	if (status & TXFREEflag) {	/* transmit _DID_ finish */
776 		msg = " - missed IRQ?";
777 	} else {
778 		msg = "";
779 		dev->stats.tx_aborted_errors++;
780 		lp->timed_out = 1;
781 		lp->hw.command(dev, NOTXcmd | (lp->cur_tx << 3));
782 	}
783 	dev->stats.tx_errors++;
784 
785 	/* make sure we didn't miss a TX or a EXC NAK IRQ */
786 	lp->hw.intmask(dev, 0);
787 	lp->intmask |= TXFREEflag | EXCNAKflag;
788 	lp->hw.intmask(dev, lp->intmask);
789 
790 	spin_unlock_irqrestore(&lp->lock, flags);
791 
792 	if (time_after(jiffies, lp->last_timeout + 10 * HZ)) {
793 		arc_printk(D_EXTRA, dev, "tx timed out%s (status=%Xh, intmask=%Xh, dest=%02Xh)\n",
794 			   msg, status, lp->intmask, lp->lasttrans_dest);
795 		lp->last_timeout = jiffies;
796 	}
797 
798 	if (lp->cur_tx == -1)
799 		netif_wake_queue(dev);
800 }
801 EXPORT_SYMBOL(arcnet_timeout);
802 
803 /* The typical workload of the driver: Handle the network interface
804  * interrupts. Establish which device needs attention, and call the correct
805  * chipset interrupt handler.
806  */
807 irqreturn_t arcnet_interrupt(int irq, void *dev_id)
808 {
809 	struct net_device *dev = dev_id;
810 	struct arcnet_local *lp;
811 	int recbuf, status, diagstatus, didsomething, boguscount;
812 	unsigned long flags;
813 	int retval = IRQ_NONE;
814 
815 	arc_printk(D_DURING, dev, "\n");
816 
817 	arc_printk(D_DURING, dev, "in arcnet_interrupt\n");
818 
819 	lp = netdev_priv(dev);
820 	BUG_ON(!lp);
821 
822 	spin_lock_irqsave(&lp->lock, flags);
823 
824 	/* RESET flag was enabled - if device is not running, we must
825 	 * clear it right away (but nothing else).
826 	 */
827 	if (!netif_running(dev)) {
828 		if (lp->hw.status(dev) & RESETflag)
829 			lp->hw.command(dev, CFLAGScmd | RESETclear);
830 		lp->hw.intmask(dev, 0);
831 		spin_unlock_irqrestore(&lp->lock, flags);
832 		return retval;
833 	}
834 
835 	arc_printk(D_DURING, dev, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
836 		   lp->hw.status(dev), lp->intmask);
837 
838 	boguscount = 5;
839 	do {
840 		status = lp->hw.status(dev);
841 		diagstatus = (status >> 8) & 0xFF;
842 
843 		arc_printk(D_DEBUG, dev, "%s: %d: %s: status=%x\n",
844 			   __FILE__, __LINE__, __func__, status);
845 		didsomething = 0;
846 
847 		/* RESET flag was enabled - card is resetting and if RX is
848 		 * disabled, it's NOT because we just got a packet.
849 		 *
850 		 * The card is in an undefined state.
851 		 * Clear it out and start over.
852 		 */
853 		if (status & RESETflag) {
854 			arc_printk(D_NORMAL, dev, "spurious reset (status=%Xh)\n",
855 				   status);
856 			arcnet_close(dev);
857 			arcnet_open(dev);
858 
859 			/* get out of the interrupt handler! */
860 			break;
861 		}
862 		/* RX is inhibited - we must have received something.
863 		 * Prepare to receive into the next buffer.
864 		 *
865 		 * We don't actually copy the received packet from the card
866 		 * until after the transmit handler runs (and possibly
867 		 * launches the next tx); this should improve latency slightly
868 		 * if we get both types of interrupts at once.
869 		 */
870 		recbuf = -1;
871 		if (status & lp->intmask & NORXflag) {
872 			recbuf = lp->cur_rx;
873 			arc_printk(D_DURING, dev, "Buffer #%d: receive irq (status=%Xh)\n",
874 				   recbuf, status);
875 
876 			lp->cur_rx = get_arcbuf(dev);
877 			if (lp->cur_rx != -1) {
878 				arc_printk(D_DURING, dev, "enabling receive to buffer #%d\n",
879 					   lp->cur_rx);
880 				lp->hw.command(dev, RXcmd | (lp->cur_rx << 3) | RXbcasts);
881 			}
882 			didsomething++;
883 		}
884 
885 		if ((diagstatus & EXCNAKflag)) {
886 			arc_printk(D_DURING, dev, "EXCNAK IRQ (diagstat=%Xh)\n",
887 				   diagstatus);
888 
889 			lp->hw.command(dev, NOTXcmd);      /* disable transmit */
890 			lp->excnak_pending = 1;
891 
892 			lp->hw.command(dev, EXCNAKclear);
893 			lp->intmask &= ~(EXCNAKflag);
894 			didsomething++;
895 		}
896 
897 		/* a transmit finished, and we're interested in it. */
898 		if ((status & lp->intmask & TXFREEflag) || lp->timed_out) {
899 			int ackstatus;
900 			lp->intmask &= ~(TXFREEflag | EXCNAKflag);
901 
902 			if (status & TXACKflag)
903 				ackstatus = 2;
904 			else if (lp->excnak_pending)
905 				ackstatus = 1;
906 			else
907 				ackstatus = 0;
908 
909 			arc_printk(D_DURING, dev, "TX IRQ (stat=%Xh)\n",
910 				   status);
911 
912 			if (lp->cur_tx != -1 && !lp->timed_out) {
913 				if (!(status & TXACKflag)) {
914 					if (lp->lasttrans_dest != 0) {
915 						arc_printk(D_EXTRA, dev,
916 							   "transmit was not acknowledged! (status=%Xh, dest=%02Xh)\n",
917 							   status,
918 							   lp->lasttrans_dest);
919 						dev->stats.tx_errors++;
920 						dev->stats.tx_carrier_errors++;
921 					} else {
922 						arc_printk(D_DURING, dev,
923 							   "broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)\n",
924 							   status,
925 							   lp->lasttrans_dest);
926 					}
927 				}
928 
929 				if (lp->outgoing.proto &&
930 				    lp->outgoing.proto->ack_tx) {
931 					lp->outgoing.proto
932 						->ack_tx(dev, ackstatus);
933 				}
934 				lp->reply_status = ackstatus;
935 				tasklet_hi_schedule(&lp->reply_tasklet);
936 			}
937 			if (lp->cur_tx != -1)
938 				release_arcbuf(dev, lp->cur_tx);
939 
940 			lp->cur_tx = -1;
941 			lp->timed_out = 0;
942 			didsomething++;
943 
944 			/* send another packet if there is one */
945 			go_tx(dev);
946 
947 			/* continue a split packet, if any */
948 			if (lp->outgoing.proto &&
949 			    lp->outgoing.proto->continue_tx) {
950 				int txbuf = get_arcbuf(dev);
951 
952 				if (txbuf != -1) {
953 					if (lp->outgoing.proto->continue_tx(dev, txbuf)) {
954 						/* that was the last segment */
955 						dev->stats.tx_bytes += lp->outgoing.skb->len;
956 						if (!lp->outgoing.proto->ack_tx) {
957 							dev_kfree_skb_irq(lp->outgoing.skb);
958 							lp->outgoing.proto = NULL;
959 						}
960 					}
961 					lp->next_tx = txbuf;
962 				}
963 			}
964 			/* inform upper layers of idleness, if necessary */
965 			if (lp->cur_tx == -1)
966 				netif_wake_queue(dev);
967 		}
968 		/* now process the received packet, if any */
969 		if (recbuf != -1) {
970 			if (BUGLVL(D_RX))
971 				arcnet_dump_packet(dev, recbuf, "rx irq", 0);
972 
973 			arcnet_rx(dev, recbuf);
974 			release_arcbuf(dev, recbuf);
975 
976 			didsomething++;
977 		}
978 		if (status & lp->intmask & RECONflag) {
979 			lp->hw.command(dev, CFLAGScmd | CONFIGclear);
980 			dev->stats.tx_carrier_errors++;
981 
982 			arc_printk(D_RECON, dev, "Network reconfiguration detected (status=%Xh)\n",
983 				   status);
984 			if (netif_carrier_ok(dev)) {
985 				netif_carrier_off(dev);
986 				netdev_info(dev, "link down\n");
987 			}
988 			mod_timer(&lp->timer, jiffies + msecs_to_jiffies(1000));
989 
990 			arcnet_led_event(dev, ARCNET_LED_EVENT_RECON);
991 			/* MYRECON bit is at bit 7 of diagstatus */
992 			if (diagstatus & 0x80)
993 				arc_printk(D_RECON, dev, "Put out that recon myself\n");
994 
995 			/* is the RECON info empty or old? */
996 			if (!lp->first_recon || !lp->last_recon ||
997 			    time_after(jiffies, lp->last_recon + HZ * 10)) {
998 				if (lp->network_down)
999 					arc_printk(D_NORMAL, dev, "reconfiguration detected: cabling restored?\n");
1000 				lp->first_recon = lp->last_recon = jiffies;
1001 				lp->num_recons = lp->network_down = 0;
1002 
1003 				arc_printk(D_DURING, dev, "recon: clearing counters.\n");
1004 			} else {	/* add to current RECON counter */
1005 				lp->last_recon = jiffies;
1006 				lp->num_recons++;
1007 
1008 				arc_printk(D_DURING, dev, "recon: counter=%d, time=%lds, net=%d\n",
1009 					   lp->num_recons,
1010 					   (lp->last_recon - lp->first_recon) / HZ,
1011 					   lp->network_down);
1012 
1013 				/* if network is marked up;
1014 				 * and first_recon and last_recon are 60+ apart;
1015 				 * and the average no. of recons counted is
1016 				 *    > RECON_THRESHOLD/min;
1017 				 * then print a warning message.
1018 				 */
1019 				if (!lp->network_down &&
1020 				    (lp->last_recon - lp->first_recon) <= HZ * 60 &&
1021 				    lp->num_recons >= RECON_THRESHOLD) {
1022 					lp->network_down = 1;
1023 					arc_printk(D_NORMAL, dev, "many reconfigurations detected: cabling problem?\n");
1024 				} else if (!lp->network_down &&
1025 					   lp->last_recon - lp->first_recon > HZ * 60) {
1026 					/* reset counters if we've gone for
1027 					 *  over a minute.
1028 					 */
1029 					lp->first_recon = lp->last_recon;
1030 					lp->num_recons = 1;
1031 				}
1032 			}
1033 		} else if (lp->network_down &&
1034 			   time_after(jiffies, lp->last_recon + HZ * 10)) {
1035 			if (lp->network_down)
1036 				arc_printk(D_NORMAL, dev, "cabling restored?\n");
1037 			lp->first_recon = lp->last_recon = 0;
1038 			lp->num_recons = lp->network_down = 0;
1039 
1040 			arc_printk(D_DURING, dev, "not recon: clearing counters anyway.\n");
1041 			netif_carrier_on(dev);
1042 		}
1043 
1044 		if (didsomething)
1045 			retval |= IRQ_HANDLED;
1046 	} while (--boguscount && didsomething);
1047 
1048 	arc_printk(D_DURING, dev, "arcnet_interrupt complete (status=%Xh, count=%d)\n",
1049 		   lp->hw.status(dev), boguscount);
1050 	arc_printk(D_DURING, dev, "\n");
1051 
1052 	lp->hw.intmask(dev, 0);
1053 	udelay(1);
1054 	lp->hw.intmask(dev, lp->intmask);
1055 
1056 	spin_unlock_irqrestore(&lp->lock, flags);
1057 	return retval;
1058 }
1059 EXPORT_SYMBOL(arcnet_interrupt);
1060 
1061 /* This is a generic packet receiver that calls arcnet??_rx depending on the
1062  * protocol ID found.
1063  */
1064 static void arcnet_rx(struct net_device *dev, int bufnum)
1065 {
1066 	struct arcnet_local *lp = netdev_priv(dev);
1067 	struct archdr pkt;
1068 	struct arc_rfc1201 *soft;
1069 	int length, ofs;
1070 
1071 	soft = &pkt.soft.rfc1201;
1072 
1073 	lp->hw.copy_from_card(dev, bufnum, 0, &pkt, ARC_HDR_SIZE);
1074 	if (pkt.hard.offset[0]) {
1075 		ofs = pkt.hard.offset[0];
1076 		length = 256 - ofs;
1077 	} else {
1078 		ofs = pkt.hard.offset[1];
1079 		length = 512 - ofs;
1080 	}
1081 
1082 	/* get the full header, if possible */
1083 	if (sizeof(pkt.soft) <= length) {
1084 		lp->hw.copy_from_card(dev, bufnum, ofs, soft, sizeof(pkt.soft));
1085 	} else {
1086 		memset(&pkt.soft, 0, sizeof(pkt.soft));
1087 		lp->hw.copy_from_card(dev, bufnum, ofs, soft, length);
1088 	}
1089 
1090 	arc_printk(D_DURING, dev, "Buffer #%d: received packet from %02Xh to %02Xh (%d+4 bytes)\n",
1091 		   bufnum, pkt.hard.source, pkt.hard.dest, length);
1092 
1093 	dev->stats.rx_packets++;
1094 	dev->stats.rx_bytes += length + ARC_HDR_SIZE;
1095 
1096 	/* call the right receiver for the protocol */
1097 	if (arc_proto_map[soft->proto]->is_ip) {
1098 		if (BUGLVL(D_PROTO)) {
1099 			struct ArcProto
1100 			*oldp = arc_proto_map[lp->default_proto[pkt.hard.source]],
1101 			*newp = arc_proto_map[soft->proto];
1102 
1103 			if (oldp != newp) {
1104 				arc_printk(D_PROTO, dev,
1105 					   "got protocol %02Xh; encap for host %02Xh is now '%c' (was '%c')\n",
1106 					   soft->proto, pkt.hard.source,
1107 					   newp->suffix, oldp->suffix);
1108 			}
1109 		}
1110 
1111 		/* broadcasts will always be done with the last-used encap. */
1112 		lp->default_proto[0] = soft->proto;
1113 
1114 		/* in striking contrast, the following isn't a hack. */
1115 		lp->default_proto[pkt.hard.source] = soft->proto;
1116 	}
1117 	/* call the protocol-specific receiver. */
1118 	arc_proto_map[soft->proto]->rx(dev, bufnum, &pkt, length);
1119 }
1120 
1121 static void null_rx(struct net_device *dev, int bufnum,
1122 		    struct archdr *pkthdr, int length)
1123 {
1124 	arc_printk(D_PROTO, dev,
1125 		   "rx: don't know how to deal with proto %02Xh from host %02Xh.\n",
1126 		   pkthdr->soft.rfc1201.proto, pkthdr->hard.source);
1127 }
1128 
1129 static int null_build_header(struct sk_buff *skb, struct net_device *dev,
1130 			     unsigned short type, uint8_t daddr)
1131 {
1132 	struct arcnet_local *lp = netdev_priv(dev);
1133 
1134 	arc_printk(D_PROTO, dev,
1135 		   "tx: can't build header for encap %02Xh; load a protocol driver.\n",
1136 		   lp->default_proto[daddr]);
1137 
1138 	/* always fails */
1139 	return 0;
1140 }
1141 
1142 /* the "do nothing" prepare_tx function warns that there's nothing to do. */
1143 static int null_prepare_tx(struct net_device *dev, struct archdr *pkt,
1144 			   int length, int bufnum)
1145 {
1146 	struct arcnet_local *lp = netdev_priv(dev);
1147 	struct arc_hardware newpkt;
1148 
1149 	arc_printk(D_PROTO, dev, "tx: no encap for this host; load a protocol driver.\n");
1150 
1151 	/* send a packet to myself -- will never get received, of course */
1152 	newpkt.source = newpkt.dest = dev->dev_addr[0];
1153 
1154 	/* only one byte of actual data (and it's random) */
1155 	newpkt.offset[0] = 0xFF;
1156 
1157 	lp->hw.copy_to_card(dev, bufnum, 0, &newpkt, ARC_HDR_SIZE);
1158 
1159 	return 1;		/* done */
1160 }
1161