xref: /netbsd-src/sys/arch/macppc/dev/am79c950.c (revision bbde328be4e75ea9ad02e9715ea13ca54b797ada)
1 /*	$NetBSD: am79c950.c,v 1.29 2010/04/05 07:19:30 joerg 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 1.29 2010/04/05 07:19:30 joerg 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 <uvm/uvm_extern.h>
54 
55 #include <net/if.h>
56 #include <net/if_dl.h>
57 #include <net/if_ether.h>
58 #include <net/if_media.h>
59 
60 #ifdef INET
61 #include <netinet/in.h>
62 #include <netinet/if_inarp.h>
63 #include <netinet/in_systm.h>
64 #include <netinet/in_var.h>
65 #include <netinet/ip.h>
66 #endif
67 
68 #include <net/bpf.h>
69 #include <net/bpfdesc.h>
70 
71 #include <machine/bus.h>
72 
73 #include <macppc/dev/am79c950reg.h>
74 #include <macppc/dev/if_mcvar.h>
75 
76 hide void	mcwatchdog(struct ifnet *);
77 hide int	mcinit(struct mc_softc *sc);
78 hide int	mcstop(struct mc_softc *sc);
79 hide int	mcioctl(struct ifnet *ifp, u_long cmd, void *data);
80 hide void	mcstart(struct ifnet *ifp);
81 hide void	mcreset(struct mc_softc *sc);
82 
83 integrate u_int	maceput(struct mc_softc *sc, struct mbuf *m0);
84 integrate void	mc_tint(struct mc_softc *sc);
85 integrate void	mace_read(struct mc_softc *, uint8_t *, int);
86 integrate struct mbuf *mace_get(struct mc_softc *, uint8_t *, int);
87 static void mace_calcladrf(struct ethercom *ac, u_int8_t *af);
88 static inline u_int16_t ether_cmp(void *, void *);
89 static int mc_mediachange(struct ifnet *);
90 static void mc_mediastatus(struct ifnet *, struct ifmediareq *);
91 
92 /*
93  * Compare two Ether/802 addresses for equality, inlined and
94  * unrolled for speed.  Use this like memcmp().
95  *
96  * XXX: Add <machine/inlines.h> for stuff like this?
97  * XXX: or maybe add it to libkern.h instead?
98  *
99  * "I'd love to have an inline assembler version of this."
100  * XXX: Who wanted that? mycroft?  I wrote one, but this
101  * version in C is as good as hand-coded assembly. -gwr
102  *
103  * Please do NOT tweak this without looking at the actual
104  * assembly code generated before and after your tweaks!
105  */
106 static inline u_int16_t
107 ether_cmp(void *one, void *two)
108 {
109 	register u_int16_t *a = (u_short *) one;
110 	register u_int16_t *b = (u_short *) two;
111 	register u_int16_t diff;
112 
113 #ifdef	m68k
114 	/*
115 	 * The post-increment-pointer form produces the best
116 	 * machine code for m68k.  This was carefully tuned
117 	 * so it compiles to just 8 short (2-byte) op-codes!
118 	 */
119 	diff  = *a++ - *b++;
120 	diff |= *a++ - *b++;
121 	diff |= *a++ - *b++;
122 #else
123 	/*
124 	 * Most modern CPUs do better with a single expresion.
125 	 * Note that short-cut evaluation is NOT helpful here,
126 	 * because it just makes the code longer, not faster!
127 	 */
128 	diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
129 #endif
130 
131 	return (diff);
132 }
133 
134 #define ETHER_CMP	ether_cmp
135 
136 /*
137  * Interface exists: make available by filling in network interface
138  * record.  System will initialize the interface when it is ready
139  * to accept packets.
140  */
141 int
142 mcsetup(struct mc_softc *sc, u_int8_t *lladdr)
143 {
144 	struct ifnet *ifp = &sc->sc_if;
145 
146 	/* reset the chip and disable all interrupts */
147 	NIC_PUT(sc, MACE_BIUCC, SWRST);
148 	DELAY(100);
149 	NIC_PUT(sc, MACE_IMR, ~0);
150 
151 	memcpy(sc->sc_enaddr, lladdr, ETHER_ADDR_LEN);
152 	printf(": address %s\n", ether_sprintf(lladdr));
153 
154 	memcpy(ifp->if_xname, sc->sc_dev.dv_xname, IFNAMSIZ);
155 	ifp->if_softc = sc;
156 	ifp->if_ioctl = mcioctl;
157 	ifp->if_start = mcstart;
158 	ifp->if_flags =
159 	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
160 	ifp->if_watchdog = mcwatchdog;
161 
162 	/* initialize ifmedia structures */
163 	ifmedia_init(&sc->sc_media, 0, mc_mediachange, mc_mediastatus);
164 	ifmedia_add(&sc->sc_media, IFM_ETHER|IFM_MANUAL, 0, NULL);
165 	ifmedia_set(&sc->sc_media, IFM_ETHER|IFM_MANUAL);
166 
167 	if_attach(ifp);
168 	ether_ifattach(ifp, lladdr);
169 
170 	return (0);
171 }
172 
173 hide int
174 mcioctl(struct ifnet *ifp, u_long cmd, void *data)
175 {
176 	struct mc_softc *sc = ifp->if_softc;
177 	struct ifaddr *ifa;
178 	struct ifreq *ifr;
179 
180 	int	s = splnet(), err = 0;
181 
182 	switch (cmd) {
183 
184 	case SIOCINITIFADDR:
185 		ifa = (struct ifaddr *)data;
186 		ifp->if_flags |= IFF_UP;
187 		mcinit(sc);
188 		switch (ifa->ifa_addr->sa_family) {
189 #ifdef INET
190 		case AF_INET:
191 			arp_ifinit(ifp, ifa);
192 			break;
193 #endif
194 		default:
195 			break;
196 		}
197 		break;
198 
199 	case SIOCSIFFLAGS:
200 		if ((err = ifioctl_common(ifp, cmd, data)) != 0)
201 			break;
202 		/* XXX see the comment in ed_ioctl() about code re-use */
203 		if ((ifp->if_flags & IFF_UP) == 0 &&
204 		    (ifp->if_flags & IFF_RUNNING) != 0) {
205 			/*
206 			 * If interface is marked down and it is running,
207 			 * then stop it.
208 			 */
209 			mcstop(sc);
210 			ifp->if_flags &= ~IFF_RUNNING;
211 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
212 		    (ifp->if_flags & IFF_RUNNING) == 0) {
213 			/*
214 			 * If interface is marked up and it is stopped,
215 			 * then start it.
216 			 */
217 			(void)mcinit(sc);
218 		} else {
219 			/*
220 			 * reset the interface to pick up any other changes
221 			 * in flags
222 			 */
223 			mcreset(sc);
224 			mcstart(ifp);
225 		}
226 		break;
227 
228 	case SIOCADDMULTI:
229 	case SIOCDELMULTI:
230 		if ((err = ether_ioctl(ifp, cmd, data)) == ENETRESET) {
231 			/*
232 			 * Multicast list has changed; set the hardware
233 			 * filter accordingly. But remember UP flag!
234 			 */
235 			if (ifp->if_flags & IFF_RUNNING)
236 				mcreset(sc);
237 			err = 0;
238 		}
239 		break;
240 
241 	case SIOCGIFMEDIA:
242 	case SIOCSIFMEDIA:
243 		ifr = (struct ifreq *) data;
244 		err = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
245 		break;
246 
247 	default:
248 		err = ether_ioctl(ifp, cmd, data);
249 		break;
250 	}
251 	splx(s);
252 	return (err);
253 }
254 
255 /*
256  * Encapsulate a packet of type family for the local net.
257  */
258 hide void
259 mcstart(struct ifnet *ifp)
260 {
261 	struct mc_softc	*sc = ifp->if_softc;
262 	struct mbuf	*m;
263 
264 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
265 		return;
266 
267 	while (1) {
268 		if (ifp->if_flags & IFF_OACTIVE)
269 			return;
270 
271 		IF_DEQUEUE(&ifp->if_snd, m);
272 		if (m == 0)
273 			return;
274 
275 		/*
276 		 * If bpf is listening on this interface, let it
277 		 * see the packet before we commit it to the wire.
278 		 */
279 		bpf_mtap(ifp, m);
280 
281 		/*
282 		 * Copy the mbuf chain into the transmit buffer.
283 		 */
284 		ifp->if_flags |= IFF_OACTIVE;
285 		maceput(sc, m);
286 
287 		ifp->if_opackets++;		/* # of pkts */
288 	}
289 }
290 
291 /*
292  * reset and restart the MACE.  Called in case of fatal
293  * hardware/software errors.
294  */
295 hide void
296 mcreset(struct mc_softc *sc)
297 {
298 	mcstop(sc);
299 	mcinit(sc);
300 }
301 
302 hide int
303 mcinit(struct mc_softc *sc)
304 {
305 	int s;
306 	u_int8_t maccc, ladrf[8];
307 
308 	if (sc->sc_if.if_flags & IFF_RUNNING)
309 		/* already running */
310 		return (0);
311 
312 	s = splnet();
313 
314 	NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc);
315 	NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc);
316 	NIC_PUT(sc, MACE_IMR, ~0); /* disable all interrupts */
317 	NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc);
318 
319 	NIC_PUT(sc, MACE_UTR, RTRD); /* disable reserved test registers */
320 
321 	/* set MAC address */
322 	NIC_PUT(sc, MACE_IAC, ADDRCHG);
323 	while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
324 		;
325 	NIC_PUT(sc, MACE_IAC, PHYADDR);
326 	bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR),
327 	    sc->sc_enaddr, ETHER_ADDR_LEN);
328 
329 	/* set logical address filter */
330 	mace_calcladrf(&sc->sc_ethercom, ladrf);
331 
332 	NIC_PUT(sc, MACE_IAC, ADDRCHG);
333 	while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
334 		;
335 	NIC_PUT(sc, MACE_IAC, LOGADDR);
336 	bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF),
337 	    ladrf, 8);
338 
339 	NIC_PUT(sc, MACE_XMTFC, APADXMT);
340 	/*
341 	 * No need to autostrip padding on receive... Ethernet frames
342 	 * don't have a length field, unlike 802.3 frames, so the MACE
343 	 * can't figure out the length of the packet anyways.
344 	 */
345 	NIC_PUT(sc, MACE_RCVFC, 0);
346 
347 	maccc = ENXMT | ENRCV;
348 	if (sc->sc_if.if_flags & IFF_PROMISC)
349 		maccc |= PROM;
350 
351 	NIC_PUT(sc, MACE_MACCC, maccc);
352 
353 	if (sc->sc_bus_init)
354 		(*sc->sc_bus_init)(sc);
355 
356 	/*
357 	 * Enable all interrupts except receive, since we use the DMA
358 	 * completion interrupt for that.
359 	 */
360 	NIC_PUT(sc, MACE_IMR, RCVINTM);
361 
362 	/* flag interface as "running" */
363 	sc->sc_if.if_flags |= IFF_RUNNING;
364 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
365 
366 	splx(s);
367 	return (0);
368 }
369 
370 /*
371  * close down an interface and free its buffers
372  * Called on final close of device, or if mcinit() fails
373  * part way through.
374  */
375 hide int
376 mcstop(struct mc_softc *sc)
377 {
378 	int	s = splnet();
379 
380 	NIC_PUT(sc, MACE_BIUCC, SWRST);
381 	DELAY(100);
382 
383 	sc->sc_if.if_timer = 0;
384 	sc->sc_if.if_flags &= ~IFF_RUNNING;
385 
386 	splx(s);
387 	return (0);
388 }
389 
390 /*
391  * Called if any Tx packets remain unsent after 5 seconds,
392  * In all cases we just reset the chip, and any retransmission
393  * will be handled by higher level protocol timeouts.
394  */
395 hide void
396 mcwatchdog(struct ifnet *ifp)
397 {
398 	struct mc_softc *sc = ifp->if_softc;
399 
400 	printf("mcwatchdog: resetting chip\n");
401 	mcreset(sc);
402 }
403 
404 /*
405  * stuff packet into MACE (at splnet)
406  */
407 integrate u_int
408 maceput(struct mc_softc *sc, struct mbuf *m)
409 {
410 	struct mbuf *n;
411 	u_int len, totlen = 0;
412 	u_char *buff;
413 
414 	buff = sc->sc_txbuf;
415 
416 	for (; m; m = n) {
417 		u_char *data = mtod(m, u_char *);
418 		len = m->m_len;
419 		totlen += len;
420 		memcpy(buff, data, len);
421 		buff += len;
422 		MFREE(m, n);
423 	}
424 
425 	if (totlen > PAGE_SIZE)
426 		panic("%s: maceput: packet overflow", sc->sc_dev.dv_xname);
427 
428 #if 0
429 	if (totlen < ETHERMIN + sizeof(struct ether_header)) {
430 		int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
431 		memset(sc->sc_txbuf + totlen, 0, pad);
432 		totlen = ETHERMIN + sizeof(struct ether_header);
433 	}
434 #endif
435 
436 	(*sc->sc_putpacket)(sc, totlen);
437 
438 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
439 	return (totlen);
440 }
441 
442 int
443 mcintr(void *arg)
444 {
445 	struct mc_softc *sc = arg;
446 	u_int8_t ir;
447 
448 	ir = NIC_GET(sc, MACE_IR) & ~NIC_GET(sc, MACE_IMR);
449 	if (ir == 0)
450 		return 0;
451 
452 	if (ir & JAB) {
453 #ifdef MCDEBUG
454 		printf("%s: jabber error\n", sc->sc_dev.dv_xname);
455 #endif
456 		sc->sc_if.if_oerrors++;
457 	}
458 
459 	if (ir & BABL) {
460 #ifdef MCDEBUG
461 		printf("%s: babble\n", sc->sc_dev.dv_xname);
462 #endif
463 		sc->sc_if.if_oerrors++;
464 	}
465 
466 	if (ir & CERR) {
467 		printf("%s: collision error\n", sc->sc_dev.dv_xname);
468 		sc->sc_if.if_collisions++;
469 	}
470 
471 	/*
472 	 * Pretend we have carrier; if we don't this will be cleared
473 	 * shortly.
474 	 */
475 	sc->sc_havecarrier = 1;
476 
477 	if (ir & XMTINT)
478 		mc_tint(sc);
479 
480 	if (ir & RCVINT)
481 		mc_rint(sc);
482 
483 	return 1;
484 }
485 
486 integrate void
487 mc_tint(struct mc_softc *sc)
488 {
489 	u_int8_t xmtrc, xmtfs;
490 
491 	xmtrc = NIC_GET(sc, MACE_XMTRC);
492 	xmtfs = NIC_GET(sc, MACE_XMTFS);
493 
494 	if ((xmtfs & XMTSV) == 0)
495 		return;
496 
497 	if (xmtfs & UFLO) {
498 		printf("%s: underflow\n", sc->sc_dev.dv_xname);
499 		mcreset(sc);
500 		return;
501 	}
502 
503 	if (xmtfs & LCOL) {
504 		printf("%s: late collision\n", sc->sc_dev.dv_xname);
505 		sc->sc_if.if_oerrors++;
506 		sc->sc_if.if_collisions++;
507 	}
508 
509 	if (xmtfs & MORE)
510 		/* Real number is unknown. */
511 		sc->sc_if.if_collisions += 2;
512 	else if (xmtfs & ONE)
513 		sc->sc_if.if_collisions++;
514 	else if (xmtfs & RTRY) {
515 		sc->sc_if.if_collisions += 16;
516 		sc->sc_if.if_oerrors++;
517 	}
518 
519 	if (xmtfs & LCAR) {
520 		sc->sc_havecarrier = 0;
521 		printf("%s: lost carrier\n", sc->sc_dev.dv_xname);
522 		sc->sc_if.if_oerrors++;
523 	}
524 
525 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
526 	sc->sc_if.if_timer = 0;
527 	mcstart(&sc->sc_if);
528 }
529 
530 void
531 mc_rint(struct mc_softc *sc)
532 {
533 #define	rxf	sc->sc_rxframe
534 	u_int len;
535 
536 	len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4;
537 
538 #ifdef MCDEBUG
539 	if (rxf.rx_rcvsts & 0xf0)
540 		printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n",
541 		    sc->sc_dev.dv_xname, rxf.rx_rcvcnt, rxf.rx_rcvsts,
542 		    rxf.rx_rntpc, rxf.rx_rcvcc);
543 #endif
544 
545 	if (rxf.rx_rcvsts & OFLO) {
546 		printf("%s: receive FIFO overflow\n", sc->sc_dev.dv_xname);
547 		sc->sc_if.if_ierrors++;
548 		return;
549 	}
550 
551 	if (rxf.rx_rcvsts & CLSN)
552 		sc->sc_if.if_collisions++;
553 
554 	if (rxf.rx_rcvsts & FRAM) {
555 #ifdef MCDEBUG
556 		printf("%s: framing error\n", sc->sc_dev.dv_xname);
557 #endif
558 		sc->sc_if.if_ierrors++;
559 		return;
560 	}
561 
562 	if (rxf.rx_rcvsts & FCS) {
563 #ifdef MCDEBUG
564 		printf("%s: frame control checksum error\n", sc->sc_dev.dv_xname);
565 #endif
566 		sc->sc_if.if_ierrors++;
567 		return;
568 	}
569 
570 	mace_read(sc, rxf.rx_frame, len);
571 #undef	rxf
572 }
573 
574 integrate void
575 mace_read(struct mc_softc *sc, uint8_t *pkt, int len)
576 {
577 	struct ifnet *ifp = &sc->sc_if;
578 	struct mbuf *m;
579 
580 	if (len <= sizeof(struct ether_header) ||
581 	    len > ETHERMTU + sizeof(struct ether_header)) {
582 #ifdef MCDEBUG
583 		printf("%s: invalid packet size %d; dropping\n",
584 		    sc->sc_dev.dv_xname, len);
585 #endif
586 		ifp->if_ierrors++;
587 		return;
588 	}
589 
590 	m = mace_get(sc, pkt, len);
591 	if (m == NULL) {
592 		ifp->if_ierrors++;
593 		return;
594 	}
595 
596 	ifp->if_ipackets++;
597 
598 	/* Pass this up to any BPF listeners. */
599 	bpf_mtap(ifp, m);
600 
601 	/* Pass the packet up. */
602 	(*ifp->if_input)(ifp, m);
603 }
604 
605 /*
606  * Pull data off an interface.
607  * Len is length of data, with local net header stripped.
608  * We copy the data into mbufs.  When full cluster sized units are present
609  * we copy into clusters.
610  */
611 integrate struct mbuf *
612 mace_get(struct mc_softc *sc, uint8_t *pkt, int totlen)
613 {
614 	register struct mbuf *m;
615 	struct mbuf *top, **mp;
616 	int len;
617 
618 	MGETHDR(m, M_DONTWAIT, MT_DATA);
619 	if (m == 0)
620 		return (0);
621 	m->m_pkthdr.rcvif = &sc->sc_if;
622 	m->m_pkthdr.len = totlen;
623 	len = MHLEN;
624 	top = 0;
625 	mp = &top;
626 
627 	while (totlen > 0) {
628 		if (top) {
629 			MGET(m, M_DONTWAIT, MT_DATA);
630 			if (m == 0) {
631 				m_freem(top);
632 				return 0;
633 			}
634 			len = MLEN;
635 		}
636 		if (totlen >= MINCLSIZE) {
637 			MCLGET(m, M_DONTWAIT);
638 			if ((m->m_flags & M_EXT) == 0) {
639 				m_free(m);
640 				m_freem(top);
641 				return 0;
642 			}
643 			len = MCLBYTES;
644 		}
645 		m->m_len = len = min(totlen, len);
646 		memcpy(mtod(m, void *), pkt, len);
647 		pkt += len;
648 		totlen -= len;
649 		*mp = m;
650 		mp = &m->m_next;
651 	}
652 
653 	return (top);
654 }
655 
656 /*
657  * Go through the list of multicast addresses and calculate the logical
658  * address filter.
659  */
660 void
661 mace_calcladrf(struct ethercom *ac, u_int8_t *af)
662 {
663 	struct ifnet *ifp = &ac->ec_if;
664 	struct ether_multi *enm;
665 	register u_char *cp, c;
666 	register u_int32_t crc;
667 	register int i, len;
668 	struct ether_multistep step;
669 
670 	/*
671 	 * Set up multicast address filter by passing all multicast addresses
672 	 * through a crc generator, and then using the high order 6 bits as an
673 	 * index into the 64 bit logical address filter.  The high order bit
674 	 * selects the word, while the rest of the bits select the bit within
675 	 * the word.
676 	 */
677 
678 	*((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0;
679 
680 	ETHER_FIRST_MULTI(step, ac, enm);
681 	while (enm != NULL) {
682 		if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
683 			/*
684 			 * We must listen to a range of multicast addresses.
685 			 * For now, just accept all multicasts, rather than
686 			 * trying to set only those filter bits needed to match
687 			 * the range.  (At this time, the only use of address
688 			 * ranges is for IP multicast routing, for which the
689 			 * range is big enough to require all bits set.)
690 			 */
691 			goto allmulti;
692 		}
693 
694 		cp = enm->enm_addrlo;
695 		crc = 0xffffffff;
696 		for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
697 			c = *cp++;
698 			for (i = 8; --i >= 0;) {
699 				if ((crc & 0x01) ^ (c & 0x01)) {
700 					crc >>= 1;
701 					crc ^= 0xedb88320;
702 				} else
703 					crc >>= 1;
704 				c >>= 1;
705 			}
706 		}
707 		/* Just want the 6 most significant bits. */
708 		crc >>= 26;
709 
710 		/* Set the corresponding bit in the filter. */
711 		af[crc >> 3] |= 1 << (crc & 7);
712 
713 		ETHER_NEXT_MULTI(step, enm);
714 	}
715 	ifp->if_flags &= ~IFF_ALLMULTI;
716 	return;
717 
718 allmulti:
719 	ifp->if_flags |= IFF_ALLMULTI;
720 	*((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0xffffffff;
721 }
722 
723 int
724 mc_mediachange(struct ifnet *ifp)
725 {
726 	return EINVAL;
727 }
728 
729 void
730 mc_mediastatus(struct ifnet *ifp, struct ifmediareq *ifmr)
731 {
732 	struct mc_softc *sc = ifp->if_softc;
733 
734 	if ((ifp->if_flags & IFF_UP) == 0)
735 		return;
736 
737 	if (sc->sc_havecarrier)
738 		ifmr->ifm_status |= IFM_ACTIVE;
739 }
740