xref: /netbsd-src/sys/arch/macppc/dev/am79c950.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /*	$NetBSD: am79c950.c,v 1.33 2014/03/14 21:59:41 mrg Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997 David Huang <khym@bga.com>
5  * All rights reserved.
6  *
7  * Portions of this code are based on code by Denton Gentry <denny1@home.com>,
8  * Charles M. Hannum, Yanagisawa Takeshi <yanagisw@aa.ap.titech.ac.jp>, and
9  * Jason R. Thorpe.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  *
30  */
31 
32 /*
33  * Driver for the AMD Am79C940 (MACE) ethernet chip, used for onboard
34  * ethernet on the Centris/Quadra 660av and Quadra 840av.
35  */
36 
37 #include <sys/cdefs.h>
38 __KERNEL_RCSID(0, "$NetBSD: am79c950.c,v 1.33 2014/03/14 21:59:41 mrg Exp $");
39 
40 #include "opt_inet.h"
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/mbuf.h>
45 #include <sys/buf.h>
46 #include <sys/protosw.h>
47 #include <sys/socket.h>
48 #include <sys/syslog.h>
49 #include <sys/ioctl.h>
50 #include <sys/errno.h>
51 #include <sys/device.h>
52 
53 #include <net/if.h>
54 #include <net/if_dl.h>
55 #include <net/if_ether.h>
56 #include <net/if_media.h>
57 
58 #ifdef INET
59 #include <netinet/in.h>
60 #include <netinet/if_inarp.h>
61 #include <netinet/in_systm.h>
62 #include <netinet/in_var.h>
63 #include <netinet/ip.h>
64 #endif
65 
66 #include <net/bpf.h>
67 #include <net/bpfdesc.h>
68 
69 #include <sys/bus.h>
70 
71 #include <macppc/dev/am79c950reg.h>
72 #include <macppc/dev/if_mcvar.h>
73 
74 hide void	mcwatchdog(struct ifnet *);
75 hide int	mcinit(struct mc_softc *sc);
76 hide int	mcstop(struct mc_softc *sc);
77 hide int	mcioctl(struct ifnet *ifp, u_long cmd, void *data);
78 hide void	mcstart(struct ifnet *ifp);
79 hide void	mcreset(struct mc_softc *sc);
80 
81 integrate u_int	maceput(struct mc_softc *sc, struct mbuf *m0);
82 integrate void	mc_tint(struct mc_softc *sc);
83 integrate void	mace_read(struct mc_softc *, uint8_t *, int);
84 integrate struct mbuf *mace_get(struct mc_softc *, uint8_t *, int);
85 static void mace_calcladrf(struct ethercom *ac, u_int8_t *af);
86 static inline u_int16_t ether_cmp(void *, void *);
87 static int mc_mediachange(struct ifnet *);
88 static void mc_mediastatus(struct ifnet *, struct ifmediareq *);
89 
90 /*
91  * Compare two Ether/802 addresses for equality, inlined and
92  * unrolled for speed.  Use this like memcmp().
93  *
94  * XXX: Add <machine/inlines.h> for stuff like this?
95  * XXX: or maybe add it to libkern.h instead?
96  *
97  * "I'd love to have an inline assembler version of this."
98  * XXX: Who wanted that? mycroft?  I wrote one, but this
99  * version in C is as good as hand-coded assembly. -gwr
100  *
101  * Please do NOT tweak this without looking at the actual
102  * assembly code generated before and after your tweaks!
103  */
104 static inline u_int16_t
105 ether_cmp(void *one, void *two)
106 {
107 	register u_int16_t *a = (u_short *) one;
108 	register u_int16_t *b = (u_short *) two;
109 	register u_int16_t diff;
110 
111 #ifdef	m68k
112 	/*
113 	 * The post-increment-pointer form produces the best
114 	 * machine code for m68k.  This was carefully tuned
115 	 * so it compiles to just 8 short (2-byte) op-codes!
116 	 */
117 	diff  = *a++ - *b++;
118 	diff |= *a++ - *b++;
119 	diff |= *a++ - *b++;
120 #else
121 	/*
122 	 * Most modern CPUs do better with a single expresion.
123 	 * Note that short-cut evaluation is NOT helpful here,
124 	 * because it just makes the code longer, not faster!
125 	 */
126 	diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
127 #endif
128 
129 	return (diff);
130 }
131 
132 #define ETHER_CMP	ether_cmp
133 
134 /*
135  * Interface exists: make available by filling in network interface
136  * record.  System will initialize the interface when it is ready
137  * to accept packets.
138  */
139 int
140 mcsetup(struct mc_softc *sc, u_int8_t *lladdr)
141 {
142 	struct ifnet *ifp = &sc->sc_if;
143 
144 	/* reset the chip and disable all interrupts */
145 	NIC_PUT(sc, MACE_BIUCC, SWRST);
146 	DELAY(100);
147 	NIC_PUT(sc, MACE_IMR, ~0);
148 
149 	memcpy(sc->sc_enaddr, lladdr, ETHER_ADDR_LEN);
150 	printf(": address %s\n", ether_sprintf(lladdr));
151 
152 	memcpy(ifp->if_xname, device_xname(sc->sc_dev), IFNAMSIZ);
153 	ifp->if_softc = sc;
154 	ifp->if_ioctl = mcioctl;
155 	ifp->if_start = mcstart;
156 	ifp->if_flags =
157 	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
158 	ifp->if_watchdog = mcwatchdog;
159 
160 	/* initialize ifmedia structures */
161 	ifmedia_init(&sc->sc_media, 0, mc_mediachange, mc_mediastatus);
162 	ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
163 	ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
164 
165 	if_attach(ifp);
166 	ether_ifattach(ifp, lladdr);
167 
168 	return (0);
169 }
170 
171 hide int
172 mcioctl(struct ifnet *ifp, u_long cmd, void *data)
173 {
174 	struct mc_softc *sc = ifp->if_softc;
175 	struct ifaddr *ifa;
176 	struct ifreq *ifr;
177 
178 	int	s = splnet(), err = 0;
179 
180 	switch (cmd) {
181 
182 	case SIOCINITIFADDR:
183 		ifa = (struct ifaddr *)data;
184 		ifp->if_flags |= IFF_UP;
185 		mcinit(sc);
186 		switch (ifa->ifa_addr->sa_family) {
187 #ifdef INET
188 		case AF_INET:
189 			arp_ifinit(ifp, ifa);
190 			break;
191 #endif
192 		default:
193 			break;
194 		}
195 		break;
196 
197 	case SIOCSIFFLAGS:
198 		if ((err = ifioctl_common(ifp, cmd, data)) != 0)
199 			break;
200 		/* XXX see the comment in ed_ioctl() about code re-use */
201 		if ((ifp->if_flags & IFF_UP) == 0 &&
202 		    (ifp->if_flags & IFF_RUNNING) != 0) {
203 			/*
204 			 * If interface is marked down and it is running,
205 			 * then stop it.
206 			 */
207 			mcstop(sc);
208 			ifp->if_flags &= ~IFF_RUNNING;
209 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
210 		    (ifp->if_flags & IFF_RUNNING) == 0) {
211 			/*
212 			 * If interface is marked up and it is stopped,
213 			 * then start it.
214 			 */
215 			(void)mcinit(sc);
216 		} else {
217 			/*
218 			 * reset the interface to pick up any other changes
219 			 * in flags
220 			 */
221 			mcreset(sc);
222 			mcstart(ifp);
223 		}
224 		break;
225 
226 	case SIOCADDMULTI:
227 	case SIOCDELMULTI:
228 		if ((err = ether_ioctl(ifp, cmd, data)) == ENETRESET) {
229 			/*
230 			 * Multicast list has changed; set the hardware
231 			 * filter accordingly. But remember UP flag!
232 			 */
233 			if (ifp->if_flags & IFF_RUNNING)
234 				mcreset(sc);
235 			err = 0;
236 		}
237 		break;
238 
239 	case SIOCGIFMEDIA:
240 	case SIOCSIFMEDIA:
241 		ifr = (struct ifreq *) data;
242 		err = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
243 		break;
244 
245 	default:
246 		err = ether_ioctl(ifp, cmd, data);
247 		break;
248 	}
249 	splx(s);
250 	return (err);
251 }
252 
253 /*
254  * Encapsulate a packet of type family for the local net.
255  */
256 hide void
257 mcstart(struct ifnet *ifp)
258 {
259 	struct mc_softc	*sc = ifp->if_softc;
260 	struct mbuf	*m;
261 
262 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
263 		return;
264 
265 	while (1) {
266 		if (ifp->if_flags & IFF_OACTIVE)
267 			return;
268 
269 		IF_DEQUEUE(&ifp->if_snd, m);
270 		if (m == 0)
271 			return;
272 
273 		/*
274 		 * If bpf is listening on this interface, let it
275 		 * see the packet before we commit it to the wire.
276 		 */
277 		bpf_mtap(ifp, m);
278 
279 		/*
280 		 * Copy the mbuf chain into the transmit buffer.
281 		 */
282 		ifp->if_flags |= IFF_OACTIVE;
283 		maceput(sc, m);
284 
285 		ifp->if_opackets++;		/* # of pkts */
286 	}
287 }
288 
289 /*
290  * reset and restart the MACE.  Called in case of fatal
291  * hardware/software errors.
292  */
293 hide void
294 mcreset(struct mc_softc *sc)
295 {
296 	mcstop(sc);
297 	mcinit(sc);
298 }
299 
300 hide int
301 mcinit(struct mc_softc *sc)
302 {
303 	int s;
304 	u_int8_t maccc, ladrf[8];
305 
306 	if (sc->sc_if.if_flags & IFF_RUNNING)
307 		/* already running */
308 		return (0);
309 
310 	s = splnet();
311 
312 	NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc);
313 	NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc);
314 	NIC_PUT(sc, MACE_IMR, ~0); /* disable all interrupts */
315 	NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc);
316 
317 	NIC_PUT(sc, MACE_UTR, RTRD); /* disable reserved test registers */
318 
319 	/* set MAC address */
320 	NIC_PUT(sc, MACE_IAC, ADDRCHG);
321 	while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
322 		;
323 	NIC_PUT(sc, MACE_IAC, PHYADDR);
324 	bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR),
325 	    sc->sc_enaddr, ETHER_ADDR_LEN);
326 
327 	/* set logical address filter */
328 	mace_calcladrf(&sc->sc_ethercom, ladrf);
329 
330 	NIC_PUT(sc, MACE_IAC, ADDRCHG);
331 	while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
332 		;
333 	NIC_PUT(sc, MACE_IAC, LOGADDR);
334 	bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF),
335 	    ladrf, 8);
336 
337 	NIC_PUT(sc, MACE_XMTFC, APADXMT);
338 	/*
339 	 * No need to autostrip padding on receive... Ethernet frames
340 	 * don't have a length field, unlike 802.3 frames, so the MACE
341 	 * can't figure out the length of the packet anyways.
342 	 */
343 	NIC_PUT(sc, MACE_RCVFC, 0);
344 
345 	maccc = ENXMT | ENRCV;
346 	if (sc->sc_if.if_flags & IFF_PROMISC)
347 		maccc |= PROM;
348 
349 	NIC_PUT(sc, MACE_MACCC, maccc);
350 
351 	if (sc->sc_bus_init)
352 		(*sc->sc_bus_init)(sc);
353 
354 	/*
355 	 * Enable all interrupts except receive, since we use the DMA
356 	 * completion interrupt for that.
357 	 */
358 	NIC_PUT(sc, MACE_IMR, RCVINTM);
359 
360 	/* flag interface as "running" */
361 	sc->sc_if.if_flags |= IFF_RUNNING;
362 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
363 
364 	splx(s);
365 	return (0);
366 }
367 
368 /*
369  * close down an interface and free its buffers
370  * Called on final close of device, or if mcinit() fails
371  * part way through.
372  */
373 hide int
374 mcstop(struct mc_softc *sc)
375 {
376 	int	s = splnet();
377 
378 	NIC_PUT(sc, MACE_BIUCC, SWRST);
379 	DELAY(100);
380 
381 	sc->sc_if.if_timer = 0;
382 	sc->sc_if.if_flags &= ~IFF_RUNNING;
383 
384 	splx(s);
385 	return (0);
386 }
387 
388 /*
389  * Called if any Tx packets remain unsent after 5 seconds,
390  * In all cases we just reset the chip, and any retransmission
391  * will be handled by higher level protocol timeouts.
392  */
393 hide void
394 mcwatchdog(struct ifnet *ifp)
395 {
396 	struct mc_softc *sc = ifp->if_softc;
397 
398 	printf("mcwatchdog: resetting chip\n");
399 	mcreset(sc);
400 }
401 
402 /*
403  * stuff packet into MACE (at splnet)
404  */
405 integrate u_int
406 maceput(struct mc_softc *sc, struct mbuf *m)
407 {
408 	struct mbuf *n;
409 	u_int len, totlen = 0;
410 	u_char *buff;
411 
412 	buff = sc->sc_txbuf;
413 
414 	for (; m; m = n) {
415 		u_char *data = mtod(m, u_char *);
416 		len = m->m_len;
417 		totlen += len;
418 		memcpy(buff, data, len);
419 		buff += len;
420 		MFREE(m, n);
421 	}
422 
423 	if (totlen > PAGE_SIZE)
424 		panic("%s: maceput: packet overflow", device_xname(sc->sc_dev));
425 
426 #if 0
427 	if (totlen < ETHERMIN + sizeof(struct ether_header)) {
428 		int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
429 		memset(sc->sc_txbuf + totlen, 0, pad);
430 		totlen = ETHERMIN + sizeof(struct ether_header);
431 	}
432 #endif
433 
434 	(*sc->sc_putpacket)(sc, totlen);
435 
436 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
437 	return (totlen);
438 }
439 
440 int
441 mcintr(void *arg)
442 {
443 	struct mc_softc *sc = arg;
444 	u_int8_t ir;
445 
446 	ir = NIC_GET(sc, MACE_IR) & ~NIC_GET(sc, MACE_IMR);
447 	if (ir == 0)
448 		return 0;
449 
450 	if (ir & JAB) {
451 #ifdef MCDEBUG
452 		printf("%s: jabber error\n", device_xname(sc->sc_dev));
453 #endif
454 		sc->sc_if.if_oerrors++;
455 	}
456 
457 	if (ir & BABL) {
458 #ifdef MCDEBUG
459 		printf("%s: babble\n", device_xname(sc->sc_dev));
460 #endif
461 		sc->sc_if.if_oerrors++;
462 	}
463 
464 	if (ir & CERR) {
465 		printf("%s: collision error\n", device_xname(sc->sc_dev));
466 		sc->sc_if.if_collisions++;
467 	}
468 
469 	/*
470 	 * Pretend we have carrier; if we don't this will be cleared
471 	 * shortly.
472 	 */
473 	sc->sc_havecarrier = 1;
474 
475 	if (ir & XMTINT)
476 		mc_tint(sc);
477 
478 	if (ir & RCVINT)
479 		mc_rint(sc);
480 
481 	return 1;
482 }
483 
484 integrate void
485 mc_tint(struct mc_softc *sc)
486 {
487 	u_int8_t xmtfs;
488 
489 	(void)NIC_GET(sc, MACE_XMTRC);
490 	xmtfs = NIC_GET(sc, MACE_XMTFS);
491 
492 	if ((xmtfs & XMTSV) == 0)
493 		return;
494 
495 	if (xmtfs & UFLO) {
496 		printf("%s: underflow\n", device_xname(sc->sc_dev));
497 		mcreset(sc);
498 		return;
499 	}
500 
501 	if (xmtfs & LCOL) {
502 		printf("%s: late collision\n", device_xname(sc->sc_dev));
503 		sc->sc_if.if_oerrors++;
504 		sc->sc_if.if_collisions++;
505 	}
506 
507 	if (xmtfs & MORE)
508 		/* Real number is unknown. */
509 		sc->sc_if.if_collisions += 2;
510 	else if (xmtfs & ONE)
511 		sc->sc_if.if_collisions++;
512 	else if (xmtfs & RTRY) {
513 		sc->sc_if.if_collisions += 16;
514 		sc->sc_if.if_oerrors++;
515 	}
516 
517 	if (xmtfs & LCAR) {
518 		sc->sc_havecarrier = 0;
519 		printf("%s: lost carrier\n", device_xname(sc->sc_dev));
520 		sc->sc_if.if_oerrors++;
521 	}
522 
523 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
524 	sc->sc_if.if_timer = 0;
525 	mcstart(&sc->sc_if);
526 }
527 
528 void
529 mc_rint(struct mc_softc *sc)
530 {
531 #define	rxf	sc->sc_rxframe
532 	u_int len;
533 
534 	len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4;
535 
536 #ifdef MCDEBUG
537 	if (rxf.rx_rcvsts & 0xf0)
538 		printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n",
539 		    device_xname(sc->sc_dev), rxf.rx_rcvcnt, rxf.rx_rcvsts,
540 		    rxf.rx_rntpc, rxf.rx_rcvcc);
541 #endif
542 
543 	if (rxf.rx_rcvsts & OFLO) {
544 		printf("%s: receive FIFO overflow\n", device_xname(sc->sc_dev));
545 		sc->sc_if.if_ierrors++;
546 		return;
547 	}
548 
549 	if (rxf.rx_rcvsts & CLSN)
550 		sc->sc_if.if_collisions++;
551 
552 	if (rxf.rx_rcvsts & FRAM) {
553 #ifdef MCDEBUG
554 		printf("%s: framing error\n", device_xname(sc->sc_dev));
555 #endif
556 		sc->sc_if.if_ierrors++;
557 		return;
558 	}
559 
560 	if (rxf.rx_rcvsts & FCS) {
561 #ifdef MCDEBUG
562 		printf("%s: frame control checksum error\n", device_xname(sc->sc_dev));
563 #endif
564 		sc->sc_if.if_ierrors++;
565 		return;
566 	}
567 
568 	mace_read(sc, rxf.rx_frame, len);
569 #undef	rxf
570 }
571 
572 integrate void
573 mace_read(struct mc_softc *sc, uint8_t *pkt, int len)
574 {
575 	struct ifnet *ifp = &sc->sc_if;
576 	struct mbuf *m;
577 
578 	if (len <= sizeof(struct ether_header) ||
579 	    len > ETHERMTU + sizeof(struct ether_header)) {
580 #ifdef MCDEBUG
581 		printf("%s: invalid packet size %d; dropping\n",
582 		    device_xname(sc->sc_dev), len);
583 #endif
584 		ifp->if_ierrors++;
585 		return;
586 	}
587 
588 	m = mace_get(sc, pkt, len);
589 	if (m == NULL) {
590 		ifp->if_ierrors++;
591 		return;
592 	}
593 
594 	ifp->if_ipackets++;
595 
596 	/* Pass this up to any BPF listeners. */
597 	bpf_mtap(ifp, m);
598 
599 	/* Pass the packet up. */
600 	(*ifp->if_input)(ifp, m);
601 }
602 
603 /*
604  * Pull data off an interface.
605  * Len is length of data, with local net header stripped.
606  * We copy the data into mbufs.  When full cluster sized units are present
607  * we copy into clusters.
608  */
609 integrate struct mbuf *
610 mace_get(struct mc_softc *sc, uint8_t *pkt, int totlen)
611 {
612 	register struct mbuf *m;
613 	struct mbuf *top, **mp;
614 	int len;
615 
616 	MGETHDR(m, M_DONTWAIT, MT_DATA);
617 	if (m == 0)
618 		return (0);
619 	m->m_pkthdr.rcvif = &sc->sc_if;
620 	m->m_pkthdr.len = totlen;
621 	len = MHLEN;
622 	top = 0;
623 	mp = &top;
624 
625 	while (totlen > 0) {
626 		if (top) {
627 			MGET(m, M_DONTWAIT, MT_DATA);
628 			if (m == 0) {
629 				m_freem(top);
630 				return 0;
631 			}
632 			len = MLEN;
633 		}
634 		if (totlen >= MINCLSIZE) {
635 			MCLGET(m, M_DONTWAIT);
636 			if ((m->m_flags & M_EXT) == 0) {
637 				m_free(m);
638 				m_freem(top);
639 				return 0;
640 			}
641 			len = MCLBYTES;
642 		}
643 		m->m_len = len = min(totlen, len);
644 		memcpy(mtod(m, void *), pkt, len);
645 		pkt += len;
646 		totlen -= len;
647 		*mp = m;
648 		mp = &m->m_next;
649 	}
650 
651 	return (top);
652 }
653 
654 /*
655  * Go through the list of multicast addresses and calculate the logical
656  * address filter.
657  */
658 void
659 mace_calcladrf(struct ethercom *ac, u_int8_t *af)
660 {
661 	struct ifnet *ifp = &ac->ec_if;
662 	struct ether_multi *enm;
663 	register u_char *cp, c;
664 	register u_int32_t crc;
665 	register int i, len;
666 	struct ether_multistep step;
667 
668 	/*
669 	 * Set up multicast address filter by passing all multicast addresses
670 	 * through a crc generator, and then using the high order 6 bits as an
671 	 * index into the 64 bit logical address filter.  The high order bit
672 	 * selects the word, while the rest of the bits select the bit within
673 	 * the word.
674 	 */
675 
676 	*((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0;
677 
678 	ETHER_FIRST_MULTI(step, ac, enm);
679 	while (enm != NULL) {
680 		if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
681 			/*
682 			 * We must listen to a range of multicast addresses.
683 			 * For now, just accept all multicasts, rather than
684 			 * trying to set only those filter bits needed to match
685 			 * the range.  (At this time, the only use of address
686 			 * ranges is for IP multicast routing, for which the
687 			 * range is big enough to require all bits set.)
688 			 */
689 			goto allmulti;
690 		}
691 
692 		cp = enm->enm_addrlo;
693 		crc = 0xffffffff;
694 		for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
695 			c = *cp++;
696 			for (i = 8; --i >= 0;) {
697 				if ((crc & 0x01) ^ (c & 0x01)) {
698 					crc >>= 1;
699 					crc ^= 0xedb88320;
700 				} else
701 					crc >>= 1;
702 				c >>= 1;
703 			}
704 		}
705 		/* Just want the 6 most significant bits. */
706 		crc >>= 26;
707 
708 		/* Set the corresponding bit in the filter. */
709 		af[crc >> 3] |= 1 << (crc & 7);
710 
711 		ETHER_NEXT_MULTI(step, enm);
712 	}
713 	ifp->if_flags &= ~IFF_ALLMULTI;
714 	return;
715 
716 allmulti:
717 	ifp->if_flags |= IFF_ALLMULTI;
718 	*((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0xffffffff;
719 }
720 
721 int
722 mc_mediachange(struct ifnet *ifp)
723 {
724 	return EINVAL;
725 }
726 
727 void
728 mc_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
729 {
730 	struct mc_softc *sc = ifp->if_softc;
731 
732 	if ((ifp->if_flags & IFF_UP) == 0)
733 		return;
734 
735 	if (sc->sc_havecarrier)
736 		ifmr->ifm_status |= IFM_ACTIVE;
737 }
738