xref: /netbsd-src/sys/arch/sun2/dev/if_ec.c (revision ba65fde2d7fefa7d39838fa5fa855e62bd606b5e)
1 /*	$NetBSD: if_ec.c,v 1.20 2012/02/02 19:43:00 tls Exp $	*/
2 
3 /*
4  * Copyright (c) 2001 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Matthew Fredette.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * 3Com 3C400 device driver
34  */
35 
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: if_ec.c,v 1.20 2012/02/02 19:43:00 tls Exp $");
38 
39 #include "opt_inet.h"
40 #include "opt_ns.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/errno.h>
45 #include <sys/ioctl.h>
46 #include <sys/mbuf.h>
47 #include <sys/socket.h>
48 #include <sys/syslog.h>
49 #include <sys/device.h>
50 #include <sys/endian.h>
51 #include <sys/rnd.h>
52 
53 #include <net/if.h>
54 #include <net/if_dl.h>
55 #include <net/if_types.h>
56 
57 #include <net/if_ether.h>
58 #include <net/if_media.h>
59 
60 #ifdef INET
61 #include <netinet/in.h>
62 #include <netinet/in_systm.h>
63 #include <netinet/in_var.h>
64 #include <netinet/ip.h>
65 #include <netinet/if_inarp.h>
66 #endif
67 
68 #ifdef NS
69 #include <netns/ns.h>
70 #include <netns/ns_if.h>
71 #endif
72 
73 #include <net/bpf.h>
74 #include <net/bpfdesc.h>
75 
76 #include <machine/cpu.h>
77 #include <machine/autoconf.h>
78 #include <machine/idprom.h>
79 #include <machine/bus.h>
80 #include <machine/intr.h>
81 
82 #include <sun2/dev/if_ecreg.h>
83 
84 /*
85  * Interface softc.
86  */
87 struct ec_softc {
88 	device_t sc_dev;
89 	void *sc_ih;
90 
91 	struct ethercom sc_ethercom;	/* ethernet common */
92 	struct ifmedia sc_media;	/* our supported media */
93 
94 	bus_space_tag_t sc_iot;	/* bus space tag */
95 	bus_space_handle_t sc_ioh;	/* bus space handle */
96 
97 	u_char sc_jammed;	/* nonzero if the net is jammed */
98 	u_char sc_colliding;	/* nonzero if the net is colliding */
99 	uint32_t sc_backoff_seed;	/* seed for the backoff PRNG */
100 
101 	krndsource_t rnd_source;
102 };
103 
104 /* Macros to read and write the CSR. */
105 #define	ECREG_CSR_RD bus_space_read_2(sc->sc_iot, sc->sc_ioh, ECREG_CSR)
106 #define	ECREG_CSR_WR(val) bus_space_write_2(sc->sc_iot, sc->sc_ioh, ECREG_CSR, val)
107 
108 /* After this many collisions, the packet is dropped. */
109 #define	EC_COLLISIONS_JAMMED		16
110 
111 /*
112  * Various constants used in the backoff pseudorandom
113  * number generator.
114  */
115 #define	EC_BACKOFF_PRNG_COLL_MAX	10
116 #define	EC_BACKOFF_PRNG_MUL		1103515245
117 #define	EC_BACKOFF_PRNG_ADD		12345
118 #define	EC_BACKOFF_PRNG_MASK		0x7fffffff
119 
120 /*
121  * Prototypes
122  */
123 int ec_intr(void *);
124 void ec_reset(struct ifnet *);
125 int ec_init(struct ifnet *);
126 int ec_ioctl(struct ifnet *, u_long, void *);
127 void ec_watchdog(struct ifnet *);
128 void ec_start(struct ifnet *);
129 
130 void ec_recv(struct ec_softc *, int);
131 void ec_coll(struct ec_softc *);
132 void ec_copyin(struct ec_softc *, void *, int, size_t);
133 void ec_copyout(struct ec_softc *, const void *, int, size_t);
134 
135 int ec_mediachange(struct ifnet *);
136 void ec_mediastatus(struct ifnet *, struct ifmediareq *);
137 
138 int ec_match(device_t, cfdata_t, void *);
139 void ec_attach(device_t, device_t, void *);
140 
141 CFATTACH_DECL_NEW(ec, sizeof(struct ec_softc),
142     ec_match, ec_attach, NULL, NULL);
143 
144 /*
145  * Copy board memory to kernel.
146  */
147 void
148 ec_copyin(struct ec_softc *sc, void *p, int offset, size_t size)
149 {
150 
151 	bus_space_copyin(sc->sc_iot, sc->sc_ioh, offset, p, size);
152 }
153 
154 /*
155  * Copy from kernel space to board memory.
156  */
157 void
158 ec_copyout(struct ec_softc *sc, const void *p, int offset, size_t size)
159 {
160 
161 	bus_space_copyout(sc->sc_iot, sc->sc_ioh, offset, p, size);
162 }
163 
164 int
165 ec_match(device_t parent, cfdata_t cf, void *aux)
166 {
167 	struct mbmem_attach_args *mbma = aux;
168 	bus_space_handle_t bh;
169 	bool matched;
170 
171 	/* No default Multibus address. */
172 	if (mbma->mbma_paddr == -1)
173 		return 0;
174 
175 	/* Make sure there is something there... */
176 	if (bus_space_map(mbma->mbma_bustag, mbma->mbma_paddr, ECREG_BANK_SZ,
177 	    0, &bh))
178 		return 0;
179 	matched = (bus_space_peek_2(mbma->mbma_bustag, bh, 0, NULL) == 0);
180 	bus_space_unmap(mbma->mbma_bustag, bh, ECREG_BANK_SZ);
181 	if (!matched)
182 		return 0;
183 
184 	/* Default interrupt priority. */
185 	if (mbma->mbma_pri == -1)
186 		mbma->mbma_pri = 3;
187 
188 	return 1;
189 }
190 
191 void
192 ec_attach(device_t parent, device_t self, void *aux)
193 {
194 	struct ec_softc *sc = device_private(self);
195 	struct mbmem_attach_args *mbma = aux;
196 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
197 	uint8_t myaddr[ETHER_ADDR_LEN];
198 
199 	sc->sc_dev = self;
200 
201 	aprint_normal("\n");
202 
203 	/* Map in the board control regs. */
204 	sc->sc_iot = mbma->mbma_bustag;
205 	if (bus_space_map(mbma->mbma_bustag, mbma->mbma_paddr, ECREG_BANK_SZ,
206 	    0, &sc->sc_ioh))
207 		panic("%s: can't map regs", __func__);
208 
209 	/* Reset the board. */
210 	ECREG_CSR_WR(EC_CSR_RESET);
211 	delay(160);
212 
213 	/*
214 	 * Copy out the board ROM Ethernet address,
215 	 * and use the non-vendor-ID part to seed
216 	 * our backoff pseudorandom number generator.
217 	 */
218 	bus_space_read_region_1(sc->sc_iot, sc->sc_ioh,
219 	    ECREG_AROM, myaddr, ETHER_ADDR_LEN);
220 	sc->sc_backoff_seed =
221 	    (myaddr[3] << 16) | (myaddr[4] << 8) | (myaddr[5]) | 1;
222 
223 	/* Initialize ifnet structure. */
224 	strcpy(ifp->if_xname, device_xname(self));
225 	ifp->if_softc = sc;
226 	ifp->if_start = ec_start;
227 	ifp->if_ioctl = ec_ioctl;
228 	ifp->if_init = ec_init;
229 	ifp->if_watchdog = ec_watchdog;
230 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS;
231 	IFQ_SET_READY(&ifp->if_snd);
232 
233         /* Initialize ifmedia structures. */
234 	ifmedia_init(&sc->sc_media, 0, ec_mediachange, ec_mediastatus);
235 	ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
236 	ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
237 
238 	/* Now we can attach the interface. */
239 	if_attach(ifp);
240 	idprom_etheraddr(myaddr);
241 	ether_ifattach(ifp, myaddr);
242 	aprint_normal_dev(self, "address %s\n", ether_sprintf(myaddr));
243 
244 	bus_intr_establish(mbma->mbma_bustag, mbma->mbma_pri, IPL_NET, 0,
245 	    ec_intr, sc);
246 
247 	rnd_attach_source(&sc->rnd_source, device_xname(self),
248 	    RND_TYPE_NET, 0);
249 }
250 
251 /*
252  * Reset interface.
253  */
254 void
255 ec_reset(struct ifnet *ifp)
256 {
257         int s;
258 
259         s = splnet();
260         ec_init(ifp);
261         splx(s);
262 }
263 
264 
265 /*
266  * Initialize interface.
267  */
268 int
269 ec_init(struct ifnet *ifp)
270 {
271 	struct ec_softc *sc = ifp->if_softc;
272 
273 	/* Reset the board. */
274 	ECREG_CSR_WR(EC_CSR_RESET);
275 	delay(160);
276 
277 	/* Set the Ethernet address. */
278 	bus_space_write_region_1(sc->sc_iot, sc->sc_ioh,
279 	    ECREG_ARAM, CLLADDR(sc->sc_ethercom.ec_if.if_sadl), ETHER_ADDR_LEN);
280 	ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_INTPA) | EC_CSR_AMSW);
281 	ECREG_CSR_WR(ECREG_CSR_RD & 0);
282 
283 	/* Enable interrupts. */
284 	ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_INTPA) |
285 	    EC_CSR_BBSW | EC_CSR_ABSW | EC_CSR_BINT | EC_CSR_AINT |
286 	    (ifp->if_flags & IFF_PROMISC ? EC_CSR_PROMISC : EC_CSR_PA));
287 
288 	/* Set flags appropriately. */
289 	ifp->if_flags |= IFF_RUNNING;
290 	ifp->if_flags &= ~IFF_OACTIVE;
291 
292 	/* Start output. */
293 	ec_start(ifp);
294 
295 	return 0;
296 }
297 
298 /*
299  * Start output on interface.
300  */
301 void
302 ec_start(struct ifnet *ifp)
303 {
304 	struct ec_softc *sc = ifp->if_softc;
305 	struct mbuf *m, *m0;
306 	int s;
307 	u_int count, realcount;
308 	bus_size_t off;
309 	static uint8_t padding[ETHER_MIN_LEN - ETHER_CRC_LEN] = {0};
310 
311 	s = splnet();
312 
313 	/* Don't do anything if output is active. */
314 	if ((ifp->if_flags & IFF_OACTIVE) != 0) {
315 		splx(s);
316 		return;
317 	}
318 	/* Don't do anything if the output queue is empty. */
319 	IFQ_DEQUEUE(&ifp->if_snd, m0);
320 	if (m0 == NULL) {
321 		splx(s);
322 		return;
323 	}
324 
325 	/* The BPF tap. */
326 	bpf_mtap(ifp, m0);
327 
328 	/* Size the packet. */
329 	count = EC_BUF_SZ - m0->m_pkthdr.len;
330 
331 	/* Copy the packet into the xmit buffer. */
332 	realcount = MIN(count, EC_PKT_MAXTDOFF);
333 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, ECREG_TBUF, realcount);
334 	for (off = realcount, m = m0; m != 0; off += m->m_len, m = m->m_next)
335 		ec_copyout(sc, mtod(m, uint8_t *), ECREG_TBUF + off, m->m_len);
336 	m_freem(m0);
337 	if (count - realcount)
338 		ec_copyout(sc, padding, ECREG_TBUF + off, count - realcount);
339 
340 	/* Enable the transmitter. */
341 	ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_PA) |
342 	    EC_CSR_TBSW | EC_CSR_TINT | EC_CSR_JINT);
343 	ifp->if_flags |= IFF_OACTIVE;
344 
345 	/* Done. */
346 	splx(s);
347 }
348 
349 /*
350  * Controller interrupt.
351  */
352 int
353 ec_intr(void *arg)
354 {
355 	struct ec_softc *sc = arg;
356 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
357 	int recv_first;
358 	int recv_second;
359 	int retval;
360 	struct mbuf *m0;
361 
362 	retval = 0;
363 
364 	/* Check for received packet(s). */
365 	recv_first = recv_second = 0;
366 	switch (ECREG_CSR_RD & (EC_CSR_BBSW | EC_CSR_ABSW | EC_CSR_RBBA)) {
367 
368 	case (EC_CSR_BBSW | EC_CSR_ABSW):
369 	case (EC_CSR_BBSW | EC_CSR_ABSW | EC_CSR_RBBA):
370 		/* Neither buffer is full.  Is this a transmit interrupt?
371 		 * Acknowledge the interrupt ourselves. */
372 		ECREG_CSR_WR(ECREG_CSR_RD &
373 		    (EC_CSR_TINT | EC_CSR_JINT | EC_CSR_PAMASK));
374 		ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_INTPA) |
375 		    EC_CSR_BINT | EC_CSR_AINT);
376 		break;
377 
378 	case EC_CSR_BBSW:
379 	case (EC_CSR_BBSW | EC_CSR_RBBA):
380 		/* Only the A buffer is full. */
381 		recv_first = EC_CSR_AINT;
382 		break;
383 
384 	case EC_CSR_ABSW:
385 	case (EC_CSR_ABSW | EC_CSR_RBBA):
386 		/* Only the B buffer is full. */
387 		recv_first = EC_CSR_BINT;
388 		break;
389 
390 	case 0:
391 		/* Both the A buffer and the B buffer are full, and the A
392 		 * buffer is older than the B buffer. */
393 		recv_first = EC_CSR_AINT;
394 		recv_second = EC_CSR_BINT;
395 		break;
396 
397 	case EC_CSR_RBBA:
398 		/* Both the A buffer and the B buffer are full, and the B
399 		 * buffer is older than the A buffer. */
400 		recv_first = EC_CSR_BINT;
401 		recv_second = EC_CSR_AINT;
402 		break;
403 	}
404 
405 	/* Receive packets. */
406 	if (recv_first) {
407 
408 		/* Acknowledge the interrupt. */
409 		ECREG_CSR_WR(ECREG_CSR_RD &
410 		    ((EC_CSR_BINT | EC_CSR_AINT | EC_CSR_TINT | EC_CSR_JINT |
411 		      EC_CSR_PAMASK) ^ (recv_first | recv_second)));
412 
413 		/* Receive a packet. */
414 		ec_recv(sc, recv_first);
415 
416 		/* Receive a packet. */
417 		if (recv_second)
418 			ec_recv(sc, recv_second);
419 
420 		retval++;
421 	}
422 	/* Check for a transmitted packet. */
423 	if (ifp->if_flags & IFF_OACTIVE) {
424 
425 		/* If we got a collision. */
426 		if (ECREG_CSR_RD & EC_CSR_JAM) {
427 			ECREG_CSR_WR(ECREG_CSR_RD &
428 			    (EC_CSR_BINT | EC_CSR_AINT | EC_CSR_PAMASK));
429 			sc->sc_ethercom.ec_if.if_collisions++;
430 			retval++;
431 			ec_coll(sc);
432 
433 		}
434 		/* If we transmitted a packet. */
435 		else if ((ECREG_CSR_RD & EC_CSR_TBSW) == 0) {
436 			ECREG_CSR_WR(ECREG_CSR_RD &
437 			    (EC_CSR_BINT | EC_CSR_AINT | EC_CSR_PAMASK));
438 			retval++;
439 			sc->sc_ethercom.ec_if.if_opackets++;
440 			sc->sc_jammed = 0;
441 			ifp->if_flags &= ~IFF_OACTIVE;
442 			IFQ_POLL(&ifp->if_snd, m0);
443 			if (m0 != NULL)
444 				ec_start(ifp);
445 		}
446 	} else {
447 
448 		/* Make sure we disable transmitter interrupts. */
449 		ECREG_CSR_WR(ECREG_CSR_RD &
450 		    (EC_CSR_BINT | EC_CSR_AINT | EC_CSR_PAMASK));
451 	}
452 
453 	return retval;
454 }
455 
456 /*
457  * Read in a packet from the board.
458  */
459 void
460 ec_recv(struct ec_softc *sc, int intbit)
461 {
462 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
463 	struct mbuf *m0, *m, *newm;
464 	bus_size_t buf;
465 	uint16_t status;
466 	uint16_t doff;
467 	int length, total_length;
468 
469 	buf = EC_CSR_INT_BUF(intbit);
470 
471 	/* Read in the packet status. */
472 	status = bus_space_read_2(sc->sc_iot, sc->sc_ioh, buf);
473 	doff = status & EC_PKT_DOFF;
474 
475 	for (total_length = -1, m0 = NULL;;) {
476 
477 		/* Check for an error. */
478 		if (status & (EC_PKT_FCSERR | EC_PKT_RGERR | EC_PKT_FRERR) ||
479 		    doff < EC_PKT_MINRDOFF ||
480 		    doff > EC_PKT_MAXRDOFF) {
481 			printf("%s: garbled packet, status 0x%04x; dropping\n",
482 			    device_xname(sc->sc_dev), (unsigned int)status);
483 			break;
484 		}
485 
486 		/* Adjust for the header. */
487 		total_length = doff - EC_PKT_RDOFF;
488 		buf += EC_PKT_RDOFF;
489 
490 		/* XXX - sometimes the card reports a large data offset. */
491 		if (total_length > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
492 #ifdef DEBUG
493 			printf("%s: fixing too-large length of %d\n",
494 			    device_xname(sc->sc_dev), total_length);
495 #endif
496 			total_length = (ETHER_MAX_LEN - ETHER_CRC_LEN);
497 		}
498 
499 		MGETHDR(m0, M_DONTWAIT, MT_DATA);
500 		if (m0 == NULL)
501 			break;
502 		m0->m_pkthdr.rcvif = ifp;
503 		m0->m_pkthdr.len = total_length;
504 		length = MHLEN;
505 		m = m0;
506 
507 		while (total_length > 0) {
508 			if (total_length >= MINCLSIZE) {
509 				MCLGET(m, M_DONTWAIT);
510 				if ((m->m_flags & M_EXT) == 0)
511 					break;
512 				length = MCLBYTES;
513 			}
514 			m->m_len = length = min(total_length, length);
515 			ec_copyin(sc, mtod(m, uint8_t *), buf, length);
516 			total_length -= length;
517 			buf += length;
518 
519 			if (total_length > 0) {
520 				MGET(newm, M_DONTWAIT, MT_DATA);
521 				if (newm == NULL)
522 					break;
523 				length = MLEN;
524 				m = m->m_next = newm;
525 			}
526 		}
527 		break;
528 	}
529 
530 	if (total_length == 0) {
531 		ifp->if_ipackets++;
532 
533 		/*
534 	 	* Check if there's a BPF listener on this interface.
535 	 	* If so, hand off the raw packet to BPF.
536 	 	*/
537 		bpf_mtap(ifp, m0);
538 
539 		/* Pass the packet up. */
540 		(*ifp->if_input)(ifp, m0);
541 
542 	} else {
543 		/* Something went wrong. */
544 		if (m0 != NULL)
545 			m_freem(m0);
546 		ifp->if_ierrors++;
547 	}
548 
549 	/* Give the receive buffer back to the card. */
550 	buf = EC_CSR_INT_BUF(intbit);
551 	bus_space_write_2(sc->sc_iot, sc->sc_ioh, buf, 0);
552 	ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_INTPA) |
553 	    EC_CSR_INT_BSW(intbit) | intbit);
554 }
555 
556 int
557 ec_mediachange(struct ifnet *ifp)
558 {
559 
560 	return 0;
561 }
562 
563 void
564 ec_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
565 {
566 
567 	if ((ifp->if_flags & IFF_UP) == 0)
568 		return;
569 
570 	ifmr->ifm_status = IFM_AVALID | IFM_ACTIVE;
571 }
572 
573 /*
574  * Process an ioctl request. This code needs some work - it looks pretty ugly.
575  */
576 int
577 ec_ioctl(struct ifnet *ifp, u_long cmd, void *data)
578 {
579 	struct ifaddr *ifa = (struct ifaddr *)data;
580 	struct ifreq *ifr = (struct ifreq *)data;
581 	struct ec_softc *sc = ifp->if_softc;
582 	int s, error = 0;
583 
584 	s = splnet();
585 
586 	switch (cmd) {
587 
588 	case SIOCINITIFADDR:
589 		ifp->if_flags |= IFF_UP;
590 
591 		switch (ifa->ifa_addr->sa_family) {
592 #ifdef INET
593 		case AF_INET:
594 			ec_init(ifp);
595 			arp_ifinit(ifp, ifa);
596 			break;
597 #endif
598 		default:
599 			ec_init(ifp);
600 			break;
601 		}
602 		break;
603 
604 	case SIOCSIFFLAGS:
605 		if ((error = ifioctl_common(ifp, cmd, data)) != 0)
606 			break;
607 		switch (ifp->if_flags & (IFF_UP|IFF_RUNNING)) {
608 		case IFF_RUNNING:
609 			/*
610 			 * If interface is marked down and it is running, then
611 			 * stop it.
612 			 */
613 			ifp->if_flags &= ~IFF_RUNNING;
614 			break;
615 		case IFF_UP:
616 			/*
617 			 * If interface is marked up and it is stopped, then
618 			 * start it.
619 			 */
620 			ec_init(ifp);
621 			break;
622 		default:
623 			/*
624 			 * Some other important flag might have changed, so
625 			 * reset.
626 			 */
627 			ec_reset(ifp);
628 			break;
629 		}
630 		break;
631 
632 	case SIOCGIFMEDIA:
633 	case SIOCSIFMEDIA:
634 		error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
635 		break;
636 
637 	default:
638 		error = ether_ioctl(ifp, cmd, data);
639 		break;
640 	}
641 
642 	splx(s);
643 	return error;
644 }
645 
646 /*
647  * Collision routine.
648  */
649 void
650 ec_coll(struct ec_softc *sc)
651 {
652 	struct ifnet *ifp = &sc->sc_ethercom.ec_if;
653 	u_short jams;
654 	struct mbuf *m0;
655 
656 	if ((++sc->sc_colliding) >= EC_COLLISIONS_JAMMED) {
657 		sc->sc_ethercom.ec_if.if_oerrors++;
658 		if (!sc->sc_jammed)
659 			printf("%s: ethernet jammed\n",
660 			    device_xname(sc->sc_dev));
661 		sc->sc_jammed = 1;
662 		sc->sc_colliding = 0;
663 		ifp->if_flags &= ~IFF_OACTIVE;
664 		IFQ_POLL(&ifp->if_snd, m0);
665 		if (m0 != NULL)
666 			ec_start(ifp);
667 	} else {
668 		jams = MAX(sc->sc_colliding, EC_BACKOFF_PRNG_COLL_MAX);
669 		sc->sc_backoff_seed =
670 		    ((sc->sc_backoff_seed * EC_BACKOFF_PRNG_MUL) +
671 		    EC_BACKOFF_PRNG_ADD) & EC_BACKOFF_PRNG_MASK;
672 		bus_space_write_2(sc->sc_iot, sc->sc_ioh, ECREG_BACKOFF,
673 		    -(((sc->sc_backoff_seed >> 8) & ~(-1 << jams)) + 1));
674 		ECREG_CSR_WR((ECREG_CSR_RD & EC_CSR_INTPA) |
675 		    EC_CSR_JAM | EC_CSR_TINT | EC_CSR_JINT);
676 	}
677 }
678 
679 /*
680  * Device timeout routine.
681  */
682 void
683 ec_watchdog(struct ifnet *ifp)
684 {
685 	struct ec_softc *sc = ifp->if_softc;
686 
687 	log(LOG_ERR, "%s: device timeout\n", device_xname(sc->sc_dev));
688 	sc->sc_ethercom.ec_if.if_oerrors++;
689 
690 	ec_reset(ifp);
691 }
692