if_mc.c revision 1.31.10.1 1 /* $NetBSD: if_mc.c,v 1.31.10.1 2007/10/03 19:24:06 garbled Exp $ */
2
3 /*-
4 * Copyright (c) 1997 David Huang <khym (at) azeotrope.org>
5 * All rights reserved.
6 *
7 * Portions of this code are based on code by Denton Gentry <denny1 (at) home.com>,
8 * Charles M. Hannum, Yanagisawa Takeshi <yanagisw (at) 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: if_mc.c,v 1.31.10.1 2007/10/03 19:24:06 garbled Exp $");
39
40 #include "opt_ddb.h"
41 #include "opt_inet.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/mbuf.h>
46 #include <sys/buf.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/syslog.h>
50 #include <sys/ioctl.h>
51 #include <sys/errno.h>
52 #include <sys/device.h>
53
54 #include <uvm/uvm_extern.h>
55
56 #include <net/if.h>
57 #include <net/if_dl.h>
58 #include <net/if_ether.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
69
70 #include "bpfilter.h"
71 #if NBPFILTER > 0
72 #include <net/bpf.h>
73 #include <net/bpfdesc.h>
74 #endif
75
76 #include <machine/bus.h>
77 #include <mac68k/dev/if_mcreg.h>
78 #include <mac68k/dev/if_mcvar.h>
79
80 hide void mcwatchdog(struct ifnet *);
81 hide int mcinit(struct mc_softc *);
82 hide int mcstop(struct mc_softc *);
83 hide int mcioctl(struct ifnet *, u_long, void *);
84 hide void mcstart(struct ifnet *);
85 hide void mcreset(struct mc_softc *);
86
87 integrate u_int maceput(struct mc_softc *, struct mbuf *);
88 integrate void mc_tint(struct mc_softc *);
89 integrate void mace_read(struct mc_softc *, void *, int);
90 integrate struct mbuf *mace_get(struct mc_softc *, void *, int);
91 static void mace_calcladrf(struct ethercom *, u_int8_t *);
92 static inline u_int16_t ether_cmp(void *, void *);
93
94
95 /*
96 * Compare two Ether/802 addresses for equality, inlined and
97 * unrolled for speed. Use this like bcmp().
98 *
99 * XXX: Add <machine/inlines.h> for stuff like this?
100 * XXX: or maybe add it to libkern.h instead?
101 *
102 * "I'd love to have an inline assembler version of this."
103 * XXX: Who wanted that? mycroft? I wrote one, but this
104 * version in C is as good as hand-coded assembly. -gwr
105 *
106 * Please do NOT tweak this without looking at the actual
107 * assembly code generated before and after your tweaks!
108 */
109 static inline u_int16_t
110 ether_cmp(void *one, void *two)
111 {
112 u_int16_t *a = (u_short *) one;
113 u_int16_t *b = (u_short *) two;
114 u_int16_t diff;
115
116 #ifdef m68k
117 /*
118 * The post-increment-pointer form produces the best
119 * machine code for m68k. This was carefully tuned
120 * so it compiles to just 8 short (2-byte) op-codes!
121 */
122 diff = *a++ - *b++;
123 diff |= *a++ - *b++;
124 diff |= *a++ - *b++;
125 #else
126 /*
127 * Most modern CPUs do better with a single expresion.
128 * Note that short-cut evaluation is NOT helpful here,
129 * because it just makes the code longer, not faster!
130 */
131 diff = (a[0] - b[0]) | (a[1] - b[1]) | (a[2] - b[2]);
132 #endif
133
134 return (diff);
135 }
136
137 #define ETHER_CMP ether_cmp
138
139 /*
140 * Interface exists: make available by filling in network interface
141 * record. System will initialize the interface when it is ready
142 * to accept packets.
143 */
144 int
145 mcsetup(struct mc_softc *sc, u_int8_t *lladdr)
146 {
147 struct ifnet *ifp = &sc->sc_if;
148
149 /* reset the chip and disable all interrupts */
150 NIC_PUT(sc, MACE_BIUCC, SWRST);
151 DELAY(100);
152 NIC_PUT(sc, MACE_IMR, ~0);
153
154 memcpy(sc->sc_enaddr, lladdr, ETHER_ADDR_LEN);
155 printf(": address %s\n", ether_sprintf(lladdr));
156
157 memcpy(ifp->if_xname, sc->sc_dev.dv_xname, IFNAMSIZ);
158 ifp->if_softc = sc;
159 ifp->if_ioctl = mcioctl;
160 ifp->if_start = mcstart;
161 ifp->if_flags =
162 IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
163 ifp->if_watchdog = mcwatchdog;
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
177 int s = splnet(), err = 0;
178
179 switch (cmd) {
180
181 case SIOCSIFADDR:
182 ifa = (struct ifaddr *)data;
183 ifp->if_flags |= IFF_UP;
184 switch (ifa->ifa_addr->sa_family) {
185 #ifdef INET
186 case AF_INET:
187 mcinit(sc);
188 arp_ifinit(ifp, ifa);
189 break;
190 #endif
191 default:
192 mcinit(sc);
193 break;
194 }
195 break;
196
197 case SIOCSIFFLAGS:
198 if ((ifp->if_flags & IFF_UP) == 0 &&
199 (ifp->if_flags & IFF_RUNNING) != 0) {
200 /*
201 * If interface is marked down and it is running,
202 * then stop it.
203 */
204 mcstop(sc);
205 ifp->if_flags &= ~IFF_RUNNING;
206 } else if ((ifp->if_flags & IFF_UP) != 0 &&
207 (ifp->if_flags & IFF_RUNNING) == 0) {
208 /*
209 * If interface is marked up and it is stopped,
210 * then start it.
211 */
212 (void)mcinit(sc);
213 } else {
214 /*
215 * reset the interface to pick up any other changes
216 * in flags
217 */
218 mcreset(sc);
219 mcstart(ifp);
220 }
221 break;
222
223 case SIOCADDMULTI:
224 case SIOCDELMULTI:
225 if ((err = ether_ioctl(ifp, cmd, data)) == ENETRESET) {
226 /*
227 * Multicast list has changed; set the hardware
228 * filter accordingly. But remember UP flag!
229 */
230 if (ifp->if_flags & IFF_RUNNING)
231 mcreset(sc);
232 err = 0;
233 }
234 break;
235 default:
236 err = EINVAL;
237 }
238 splx(s);
239 return (err);
240 }
241
242 /*
243 * Encapsulate a packet of type family for the local net.
244 */
245 hide void
246 mcstart(struct ifnet *ifp)
247 {
248 struct mc_softc *sc = ifp->if_softc;
249 struct mbuf *m;
250
251 if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
252 return;
253
254 while (1) {
255 if (ifp->if_flags & IFF_OACTIVE)
256 return;
257
258 IF_DEQUEUE(&ifp->if_snd, m);
259 if (m == 0)
260 return;
261
262 #if NBPFILTER > 0
263 /*
264 * If bpf is listening on this interface, let it
265 * see the packet before we commit it to the wire.
266 */
267 if (ifp->if_bpf)
268 bpf_mtap(ifp->if_bpf, m);
269 #endif
270
271 /*
272 * Copy the mbuf chain into the transmit buffer.
273 */
274 ifp->if_flags |= IFF_OACTIVE;
275 maceput(sc, m);
276
277 ifp->if_opackets++; /* # of pkts */
278 }
279 }
280
281 /*
282 * reset and restart the MACE. Called in case of fatal
283 * hardware/software errors.
284 */
285 hide void
286 mcreset(struct mc_softc *sc)
287 {
288 mcstop(sc);
289 mcinit(sc);
290 }
291
292 hide int
293 mcinit(struct mc_softc *sc)
294 {
295 int s;
296 u_int8_t maccc, ladrf[8];
297
298 if (sc->sc_if.if_flags & IFF_RUNNING)
299 /* already running */
300 return (0);
301
302 s = splnet();
303
304 NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc);
305 NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc);
306 NIC_PUT(sc, MACE_IMR, ~0); /* disable all interrupts */
307 NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc);
308
309 NIC_PUT(sc, MACE_UTR, RTRD); /* disable reserved test registers */
310
311 /* set MAC address */
312 NIC_PUT(sc, MACE_IAC, ADDRCHG);
313 while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
314 ;
315 NIC_PUT(sc, MACE_IAC, PHYADDR);
316 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR),
317 sc->sc_enaddr, ETHER_ADDR_LEN);
318
319 /* set logical address filter */
320 mace_calcladrf(&sc->sc_ethercom, ladrf);
321
322 NIC_PUT(sc, MACE_IAC, ADDRCHG);
323 while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
324 ;
325 NIC_PUT(sc, MACE_IAC, LOGADDR);
326 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF),
327 ladrf, 8);
328
329 NIC_PUT(sc, MACE_XMTFC, APADXMT);
330 /*
331 * No need to autostrip padding on receive... Ethernet frames
332 * don't have a length field, unlike 802.3 frames, so the MACE
333 * can't figure out the length of the packet anyways.
334 */
335 NIC_PUT(sc, MACE_RCVFC, 0);
336
337 maccc = ENXMT | ENRCV;
338 if (sc->sc_if.if_flags & IFF_PROMISC)
339 maccc |= PROM;
340
341 NIC_PUT(sc, MACE_MACCC, maccc);
342
343 if (sc->sc_bus_init)
344 (*sc->sc_bus_init)(sc);
345
346 /*
347 * Enable all interrupts except receive, since we use the DMA
348 * completion interrupt for that.
349 */
350 NIC_PUT(sc, MACE_IMR, RCVINTM);
351
352 /* flag interface as "running" */
353 sc->sc_if.if_flags |= IFF_RUNNING;
354 sc->sc_if.if_flags &= ~IFF_OACTIVE;
355
356 splx(s);
357 return (0);
358 }
359
360 /*
361 * close down an interface and free its buffers
362 * Called on final close of device, or if mcinit() fails
363 * part way through.
364 */
365 hide int
366 mcstop(struct mc_softc *sc)
367 {
368 int s;
369
370 s = splnet();
371
372 NIC_PUT(sc, MACE_BIUCC, SWRST);
373 DELAY(100);
374
375 sc->sc_if.if_timer = 0;
376 sc->sc_if.if_flags &= ~IFF_RUNNING;
377
378 splx(s);
379 return (0);
380 }
381
382 /*
383 * Called if any Tx packets remain unsent after 5 seconds,
384 * In all cases we just reset the chip, and any retransmission
385 * will be handled by higher level protocol timeouts.
386 */
387 hide void
388 mcwatchdog(struct ifnet *ifp)
389 {
390 struct mc_softc *sc = ifp->if_softc;
391
392 printf("mcwatchdog: resetting chip\n");
393 mcreset(sc);
394 }
395
396 /*
397 * stuff packet into MACE (at splnet)
398 */
399 integrate u_int
400 maceput(struct mc_softc *sc, struct mbuf *m)
401 {
402 struct mbuf *n;
403 u_int len, totlen = 0;
404 u_char *buff;
405
406 buff = (u_char*)sc->sc_txbuf + (sc->sc_txset == 0 ? 0 : 0x800);
407
408 for (; m; m = n) {
409 u_char *data = mtod(m, u_char *);
410 len = m->m_len;
411 totlen += len;
412 memcpy(buff, data, len);
413 buff += len;
414 MFREE(m, n);
415 }
416
417 if (totlen > PAGE_SIZE)
418 panic("%s: maceput: packet overflow", sc->sc_dev.dv_xname);
419
420 #if 0
421 if (totlen < ETHERMIN + sizeof(struct ether_header)) {
422 int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
423 memset(sc->sc_txbuf + totlen, 0, pad);
424 totlen = ETHERMIN + sizeof(struct ether_header);
425 }
426 #endif
427
428 (*sc->sc_putpacket)(sc, totlen);
429
430 sc->sc_if.if_timer = 5; /* 5 seconds to watch for failing to transmit */
431 return (totlen);
432 }
433
434 void
435 mcintr(void *arg)
436 {
437 struct mc_softc *sc = arg;
438 u_int8_t ir;
439
440 ir = NIC_GET(sc, MACE_IR) & ~NIC_GET(sc, MACE_IMR);
441 if (ir & JAB) {
442 #ifdef MCDEBUG
443 printf("%s: jabber error\n", sc->sc_dev.dv_xname);
444 #endif
445 sc->sc_if.if_oerrors++;
446 }
447
448 if (ir & BABL) {
449 #ifdef MCDEBUG
450 printf("%s: babble\n", sc->sc_dev.dv_xname);
451 #endif
452 sc->sc_if.if_oerrors++;
453 }
454
455 if (ir & CERR) {
456 #ifdef MCDEBUG
457 printf("%s: collision error\n", sc->sc_dev.dv_xname);
458 #endif
459 sc->sc_if.if_collisions++;
460 }
461
462 /*
463 * Pretend we have carrier; if we don't this will be cleared
464 * shortly.
465 */
466 sc->sc_havecarrier = 1;
467
468 if (ir & XMTINT)
469 mc_tint(sc);
470
471 if (ir & RCVINT)
472 mc_rint(sc);
473 }
474
475 integrate void
476 mc_tint(struct mc_softc *sc)
477 {
478 u_int8_t xmtrc, xmtfs;
479
480 xmtrc = NIC_GET(sc, MACE_XMTRC);
481 xmtfs = NIC_GET(sc, MACE_XMTFS);
482
483 if ((xmtfs & XMTSV) == 0)
484 return;
485
486 if (xmtfs & UFLO) {
487 printf("%s: underflow\n", sc->sc_dev.dv_xname);
488 mcreset(sc);
489 return;
490 }
491
492 if (xmtfs & LCOL) {
493 printf("%s: late collision\n", sc->sc_dev.dv_xname);
494 sc->sc_if.if_oerrors++;
495 sc->sc_if.if_collisions++;
496 }
497
498 if (xmtfs & MORE)
499 /* Real number is unknown. */
500 sc->sc_if.if_collisions += 2;
501 else if (xmtfs & ONE)
502 sc->sc_if.if_collisions++;
503 else if (xmtfs & RTRY) {
504 printf("%s: excessive collisions\n", sc->sc_dev.dv_xname);
505 sc->sc_if.if_collisions += 16;
506 sc->sc_if.if_oerrors++;
507 }
508
509 if (xmtfs & LCAR) {
510 sc->sc_havecarrier = 0;
511 printf("%s: lost carrier\n", sc->sc_dev.dv_xname);
512 sc->sc_if.if_oerrors++;
513 }
514
515 sc->sc_if.if_flags &= ~IFF_OACTIVE;
516 sc->sc_if.if_timer = 0;
517 mcstart(&sc->sc_if);
518 }
519
520 void
521 mc_rint(struct mc_softc *sc)
522 {
523 #define rxf sc->sc_rxframe
524 u_int len;
525
526 len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4;
527
528 #ifdef MCDEBUG
529 if (rxf.rx_rcvsts & 0xf0)
530 printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n",
531 sc->sc_dev.dv_xname, rxf.rx_rcvcnt, rxf.rx_rcvsts,
532 rxf.rx_rntpc, rxf.rx_rcvcc);
533 #endif
534
535 if (rxf.rx_rcvsts & OFLO) {
536 printf("%s: receive FIFO overflow\n", sc->sc_dev.dv_xname);
537 sc->sc_if.if_ierrors++;
538 return;
539 }
540
541 if (rxf.rx_rcvsts & CLSN)
542 sc->sc_if.if_collisions++;
543
544 if (rxf.rx_rcvsts & FRAM) {
545 #ifdef MCDEBUG
546 printf("%s: framing error\n", sc->sc_dev.dv_xname);
547 #endif
548 sc->sc_if.if_ierrors++;
549 return;
550 }
551
552 if (rxf.rx_rcvsts & FCS) {
553 #ifdef MCDEBUG
554 printf("%s: frame control checksum error\n", sc->sc_dev.dv_xname);
555 #endif
556 sc->sc_if.if_ierrors++;
557 return;
558 }
559
560 mace_read(sc, rxf.rx_frame, len);
561 #undef rxf
562 }
563
564 integrate void
565 mace_read(struct mc_softc *sc, void *pkt, int len)
566 {
567 struct ifnet *ifp = &sc->sc_if;
568 struct mbuf *m;
569
570 if (len <= sizeof(struct ether_header) ||
571 len > ETHERMTU + sizeof(struct ether_header)) {
572 #ifdef MCDEBUG
573 printf("%s: invalid packet size %d; dropping\n",
574 sc->sc_dev.dv_xname, len);
575 #endif
576 ifp->if_ierrors++;
577 return;
578 }
579
580 m = mace_get(sc, pkt, len);
581 if (m == NULL) {
582 ifp->if_ierrors++;
583 return;
584 }
585
586 ifp->if_ipackets++;
587
588 #if NBPFILTER > 0
589 /* Pass the packet to any BPF listeners. */
590 if (ifp->if_bpf)
591 bpf_mtap(ifp->if_bpf, m);
592 #endif
593
594 /* Pass the packet up. */
595 (*ifp->if_input)(ifp, m);
596 }
597
598 /*
599 * Pull data off an interface.
600 * Len is length of data, with local net header stripped.
601 * We copy the data into mbufs. When full cluster sized units are present
602 * we copy into clusters.
603 */
604 integrate struct mbuf *
605 mace_get(struct mc_softc *sc, void *pkt, int totlen)
606 {
607 struct mbuf *m;
608 struct mbuf *top, **mp;
609 int len;
610
611 MGETHDR(m, M_DONTWAIT, MT_DATA);
612 if (m == 0)
613 return (0);
614 m->m_pkthdr.rcvif = &sc->sc_if;
615 m->m_pkthdr.len = totlen;
616 len = MHLEN;
617 top = 0;
618 mp = ⊤
619
620 while (totlen > 0) {
621 if (top) {
622 MGET(m, M_DONTWAIT, MT_DATA);
623 if (m == 0) {
624 m_freem(top);
625 return 0;
626 }
627 len = MLEN;
628 }
629 if (totlen >= MINCLSIZE) {
630 MCLGET(m, M_DONTWAIT);
631 if ((m->m_flags & M_EXT) == 0) {
632 m_free(m);
633 m_freem(top);
634 return 0;
635 }
636 len = MCLBYTES;
637 }
638 m->m_len = len = min(totlen, len);
639 memcpy(mtod(m, void *), pkt, len);
640 pkt = (char*)pkt + len;
641 totlen -= len;
642 *mp = m;
643 mp = &m->m_next;
644 }
645
646 return (top);
647 }
648
649 /*
650 * Go through the list of multicast addresses and calculate the logical
651 * address filter.
652 */
653 void
654 mace_calcladrf(struct ethercom *ac, u_int8_t *af)
655 {
656 struct ifnet *ifp = &ac->ec_if;
657 struct ether_multi *enm;
658 u_char *cp;
659 u_int32_t crc;
660 static const u_int32_t crctab[] = {
661 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
662 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
663 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
664 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
665 };
666 int len;
667 struct ether_multistep step;
668
669 /*
670 * Set up multicast address filter by passing all multicast addresses
671 * through a crc generator, and then using the high order 6 bits as an
672 * index into the 64 bit logical address filter. The high order bit
673 * selects the word, while the rest of the bits select the bit within
674 * the word.
675 */
676
677 *((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0;
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 crc ^= *cp++;
696 crc = (crc >> 4) ^ crctab[crc & 0xf];
697 crc = (crc >> 4) ^ crctab[crc & 0xf];
698 }
699 /* Just want the 6 most significant bits. */
700 crc >>= 26;
701
702 /* Set the corresponding bit in the filter. */
703 af[crc >> 3] |= 1 << (crc & 7);
704
705 ETHER_NEXT_MULTI(step, enm);
706 }
707 ifp->if_flags &= ~IFF_ALLMULTI;
708 return;
709
710 allmulti:
711 ifp->if_flags |= IFF_ALLMULTI;
712 *((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0xffffffff;
713 }
714
715 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
716 #define bbr(v) ((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
717
718 u_char
719 mc_get_enaddr(bus_space_tag_t t, bus_space_handle_t h, bus_size_t o,
720 u_char *dst)
721 {
722 int i;
723 u_char b, csum;
724
725 /*
726 * The XOR of the 8 bytes of the ROM must be 0xff for it to be
727 * valid
728 */
729 for (i = 0, csum = 0; i < 8; i++) {
730 b = bus_space_read_1(t, h, o+16*i);
731 if (i < ETHER_ADDR_LEN)
732 dst[i] = bbr(b);
733 csum ^= b;
734 }
735
736 return csum;
737 }
738