if_mc.c revision 1.30 1 /* $NetBSD: if_mc.c,v 1.30 2007/03/04 06:00:07 christos 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 1.30 2007/03/04 06:00:07 christos 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 struct ifreq *ifr;
177
178 int s = splnet(), err = 0;
179
180 switch (cmd) {
181
182 case SIOCSIFADDR:
183 ifa = (struct ifaddr *)data;
184 ifp->if_flags |= IFF_UP;
185 switch (ifa->ifa_addr->sa_family) {
186 #ifdef INET
187 case AF_INET:
188 mcinit(sc);
189 arp_ifinit(ifp, ifa);
190 break;
191 #endif
192 default:
193 mcinit(sc);
194 break;
195 }
196 break;
197
198 case SIOCSIFFLAGS:
199 if ((ifp->if_flags & IFF_UP) == 0 &&
200 (ifp->if_flags & IFF_RUNNING) != 0) {
201 /*
202 * If interface is marked down and it is running,
203 * then stop it.
204 */
205 mcstop(sc);
206 ifp->if_flags &= ~IFF_RUNNING;
207 } else if ((ifp->if_flags & IFF_UP) != 0 &&
208 (ifp->if_flags & IFF_RUNNING) == 0) {
209 /*
210 * If interface is marked up and it is stopped,
211 * then start it.
212 */
213 (void)mcinit(sc);
214 } else {
215 /*
216 * reset the interface to pick up any other changes
217 * in flags
218 */
219 mcreset(sc);
220 mcstart(ifp);
221 }
222 break;
223
224 case SIOCADDMULTI:
225 case SIOCDELMULTI:
226 ifr = (struct ifreq *) data;
227 err = (cmd == SIOCADDMULTI) ?
228 ether_addmulti(ifr, &sc->sc_ethercom) :
229 ether_delmulti(ifr, &sc->sc_ethercom);
230
231 if (err == ENETRESET) {
232 /*
233 * Multicast list has changed; set the hardware
234 * filter accordingly. But remember UP flag!
235 */
236 if (ifp->if_flags & IFF_RUNNING)
237 mcreset(sc);
238 err = 0;
239 }
240 break;
241 default:
242 err = EINVAL;
243 }
244 splx(s);
245 return (err);
246 }
247
248 /*
249 * Encapsulate a packet of type family for the local net.
250 */
251 hide void
252 mcstart(struct ifnet *ifp)
253 {
254 struct mc_softc *sc = ifp->if_softc;
255 struct mbuf *m;
256
257 if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
258 return;
259
260 while (1) {
261 if (ifp->if_flags & IFF_OACTIVE)
262 return;
263
264 IF_DEQUEUE(&ifp->if_snd, m);
265 if (m == 0)
266 return;
267
268 #if NBPFILTER > 0
269 /*
270 * If bpf is listening on this interface, let it
271 * see the packet before we commit it to the wire.
272 */
273 if (ifp->if_bpf)
274 bpf_mtap(ifp->if_bpf, m);
275 #endif
276
277 /*
278 * Copy the mbuf chain into the transmit buffer.
279 */
280 ifp->if_flags |= IFF_OACTIVE;
281 maceput(sc, m);
282
283 ifp->if_opackets++; /* # of pkts */
284 }
285 }
286
287 /*
288 * reset and restart the MACE. Called in case of fatal
289 * hardware/software errors.
290 */
291 hide void
292 mcreset(struct mc_softc *sc)
293 {
294 mcstop(sc);
295 mcinit(sc);
296 }
297
298 hide int
299 mcinit(struct mc_softc *sc)
300 {
301 int s;
302 u_int8_t maccc, ladrf[8];
303
304 if (sc->sc_if.if_flags & IFF_RUNNING)
305 /* already running */
306 return (0);
307
308 s = splnet();
309
310 NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc);
311 NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc);
312 NIC_PUT(sc, MACE_IMR, ~0); /* disable all interrupts */
313 NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc);
314
315 NIC_PUT(sc, MACE_UTR, RTRD); /* disable reserved test registers */
316
317 /* set MAC address */
318 NIC_PUT(sc, MACE_IAC, ADDRCHG);
319 while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
320 ;
321 NIC_PUT(sc, MACE_IAC, PHYADDR);
322 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR),
323 sc->sc_enaddr, ETHER_ADDR_LEN);
324
325 /* set logical address filter */
326 mace_calcladrf(&sc->sc_ethercom, ladrf);
327
328 NIC_PUT(sc, MACE_IAC, ADDRCHG);
329 while (NIC_GET(sc, MACE_IAC) & ADDRCHG)
330 ;
331 NIC_PUT(sc, MACE_IAC, LOGADDR);
332 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF),
333 ladrf, 8);
334
335 NIC_PUT(sc, MACE_XMTFC, APADXMT);
336 /*
337 * No need to autostrip padding on receive... Ethernet frames
338 * don't have a length field, unlike 802.3 frames, so the MACE
339 * can't figure out the length of the packet anyways.
340 */
341 NIC_PUT(sc, MACE_RCVFC, 0);
342
343 maccc = ENXMT | ENRCV;
344 if (sc->sc_if.if_flags & IFF_PROMISC)
345 maccc |= PROM;
346
347 NIC_PUT(sc, MACE_MACCC, maccc);
348
349 if (sc->sc_bus_init)
350 (*sc->sc_bus_init)(sc);
351
352 /*
353 * Enable all interrupts except receive, since we use the DMA
354 * completion interrupt for that.
355 */
356 NIC_PUT(sc, MACE_IMR, RCVINTM);
357
358 /* flag interface as "running" */
359 sc->sc_if.if_flags |= IFF_RUNNING;
360 sc->sc_if.if_flags &= ~IFF_OACTIVE;
361
362 splx(s);
363 return (0);
364 }
365
366 /*
367 * close down an interface and free its buffers
368 * Called on final close of device, or if mcinit() fails
369 * part way through.
370 */
371 hide int
372 mcstop(struct mc_softc *sc)
373 {
374 int s;
375
376 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 + (sc->sc_txset == 0 ? 0 : 0x800);
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", sc->sc_dev.dv_xname);
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 void
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 & JAB) {
448 #ifdef MCDEBUG
449 printf("%s: jabber error\n", sc->sc_dev.dv_xname);
450 #endif
451 sc->sc_if.if_oerrors++;
452 }
453
454 if (ir & BABL) {
455 #ifdef MCDEBUG
456 printf("%s: babble\n", sc->sc_dev.dv_xname);
457 #endif
458 sc->sc_if.if_oerrors++;
459 }
460
461 if (ir & CERR) {
462 #ifdef MCDEBUG
463 printf("%s: collision error\n", sc->sc_dev.dv_xname);
464 #endif
465 sc->sc_if.if_collisions++;
466 }
467
468 /*
469 * Pretend we have carrier; if we don't this will be cleared
470 * shortly.
471 */
472 sc->sc_havecarrier = 1;
473
474 if (ir & XMTINT)
475 mc_tint(sc);
476
477 if (ir & RCVINT)
478 mc_rint(sc);
479 }
480
481 integrate void
482 mc_tint(struct mc_softc *sc)
483 {
484 u_int8_t xmtrc, xmtfs;
485
486 xmtrc = NIC_GET(sc, MACE_XMTRC);
487 xmtfs = NIC_GET(sc, MACE_XMTFS);
488
489 if ((xmtfs & XMTSV) == 0)
490 return;
491
492 if (xmtfs & UFLO) {
493 printf("%s: underflow\n", sc->sc_dev.dv_xname);
494 mcreset(sc);
495 return;
496 }
497
498 if (xmtfs & LCOL) {
499 printf("%s: late collision\n", sc->sc_dev.dv_xname);
500 sc->sc_if.if_oerrors++;
501 sc->sc_if.if_collisions++;
502 }
503
504 if (xmtfs & MORE)
505 /* Real number is unknown. */
506 sc->sc_if.if_collisions += 2;
507 else if (xmtfs & ONE)
508 sc->sc_if.if_collisions++;
509 else if (xmtfs & RTRY) {
510 printf("%s: excessive collisions\n", sc->sc_dev.dv_xname);
511 sc->sc_if.if_collisions += 16;
512 sc->sc_if.if_oerrors++;
513 }
514
515 if (xmtfs & LCAR) {
516 sc->sc_havecarrier = 0;
517 printf("%s: lost carrier\n", sc->sc_dev.dv_xname);
518 sc->sc_if.if_oerrors++;
519 }
520
521 sc->sc_if.if_flags &= ~IFF_OACTIVE;
522 sc->sc_if.if_timer = 0;
523 mcstart(&sc->sc_if);
524 }
525
526 void
527 mc_rint(struct mc_softc *sc)
528 {
529 #define rxf sc->sc_rxframe
530 u_int len;
531
532 len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4;
533
534 #ifdef MCDEBUG
535 if (rxf.rx_rcvsts & 0xf0)
536 printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n",
537 sc->sc_dev.dv_xname, rxf.rx_rcvcnt, rxf.rx_rcvsts,
538 rxf.rx_rntpc, rxf.rx_rcvcc);
539 #endif
540
541 if (rxf.rx_rcvsts & OFLO) {
542 printf("%s: receive FIFO overflow\n", sc->sc_dev.dv_xname);
543 sc->sc_if.if_ierrors++;
544 return;
545 }
546
547 if (rxf.rx_rcvsts & CLSN)
548 sc->sc_if.if_collisions++;
549
550 if (rxf.rx_rcvsts & FRAM) {
551 #ifdef MCDEBUG
552 printf("%s: framing error\n", sc->sc_dev.dv_xname);
553 #endif
554 sc->sc_if.if_ierrors++;
555 return;
556 }
557
558 if (rxf.rx_rcvsts & FCS) {
559 #ifdef MCDEBUG
560 printf("%s: frame control checksum error\n", sc->sc_dev.dv_xname);
561 #endif
562 sc->sc_if.if_ierrors++;
563 return;
564 }
565
566 mace_read(sc, rxf.rx_frame, len);
567 #undef rxf
568 }
569
570 integrate void
571 mace_read(struct mc_softc *sc, void *pkt, int len)
572 {
573 struct ifnet *ifp = &sc->sc_if;
574 struct mbuf *m;
575
576 if (len <= sizeof(struct ether_header) ||
577 len > ETHERMTU + sizeof(struct ether_header)) {
578 #ifdef MCDEBUG
579 printf("%s: invalid packet size %d; dropping\n",
580 sc->sc_dev.dv_xname, len);
581 #endif
582 ifp->if_ierrors++;
583 return;
584 }
585
586 m = mace_get(sc, pkt, len);
587 if (m == NULL) {
588 ifp->if_ierrors++;
589 return;
590 }
591
592 ifp->if_ipackets++;
593
594 #if NBPFILTER > 0
595 /* Pass the packet to any BPF listeners. */
596 if (ifp->if_bpf)
597 bpf_mtap(ifp->if_bpf, m);
598 #endif
599
600 /* Pass the packet up. */
601 (*ifp->if_input)(ifp, m);
602 }
603
604 /*
605 * Pull data off an interface.
606 * Len is length of data, with local net header stripped.
607 * We copy the data into mbufs. When full cluster sized units are present
608 * we copy into clusters.
609 */
610 integrate struct mbuf *
611 mace_get(struct mc_softc *sc, void *pkt, int totlen)
612 {
613 struct mbuf *m;
614 struct mbuf *top, **mp;
615 int len;
616
617 MGETHDR(m, M_DONTWAIT, MT_DATA);
618 if (m == 0)
619 return (0);
620 m->m_pkthdr.rcvif = &sc->sc_if;
621 m->m_pkthdr.len = totlen;
622 len = MHLEN;
623 top = 0;
624 mp = ⊤
625
626 while (totlen > 0) {
627 if (top) {
628 MGET(m, M_DONTWAIT, MT_DATA);
629 if (m == 0) {
630 m_freem(top);
631 return 0;
632 }
633 len = MLEN;
634 }
635 if (totlen >= MINCLSIZE) {
636 MCLGET(m, M_DONTWAIT);
637 if ((m->m_flags & M_EXT) == 0) {
638 m_free(m);
639 m_freem(top);
640 return 0;
641 }
642 len = MCLBYTES;
643 }
644 m->m_len = len = min(totlen, len);
645 memcpy(mtod(m, void *), pkt, len);
646 pkt += len;
647 totlen -= len;
648 *mp = m;
649 mp = &m->m_next;
650 }
651
652 return (top);
653 }
654
655 /*
656 * Go through the list of multicast addresses and calculate the logical
657 * address filter.
658 */
659 void
660 mace_calcladrf(struct ethercom *ac, u_int8_t *af)
661 {
662 struct ifnet *ifp = &ac->ec_if;
663 struct ether_multi *enm;
664 u_char *cp;
665 u_int32_t crc;
666 static const u_int32_t crctab[] = {
667 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
668 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
669 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
670 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
671 };
672 int len;
673 struct ether_multistep step;
674
675 /*
676 * Set up multicast address filter by passing all multicast addresses
677 * through a crc generator, and then using the high order 6 bits as an
678 * index into the 64 bit logical address filter. The high order bit
679 * selects the word, while the rest of the bits select the bit within
680 * the word.
681 */
682
683 *((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0;
684 ETHER_FIRST_MULTI(step, ac, enm);
685 while (enm != NULL) {
686 if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) {
687 /*
688 * We must listen to a range of multicast addresses.
689 * For now, just accept all multicasts, rather than
690 * trying to set only those filter bits needed to match
691 * the range. (At this time, the only use of address
692 * ranges is for IP multicast routing, for which the
693 * range is big enough to require all bits set.)
694 */
695 goto allmulti;
696 }
697
698 cp = enm->enm_addrlo;
699 crc = 0xffffffff;
700 for (len = sizeof(enm->enm_addrlo); --len >= 0;) {
701 crc ^= *cp++;
702 crc = (crc >> 4) ^ crctab[crc & 0xf];
703 crc = (crc >> 4) ^ crctab[crc & 0xf];
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 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
722 #define bbr(v) ((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
723
724 u_char
725 mc_get_enaddr(bus_space_tag_t t, bus_space_handle_t h, bus_size_t o,
726 u_char *dst)
727 {
728 int i;
729 u_char b, csum;
730
731 /*
732 * The XOR of the 8 bytes of the ROM must be 0xff for it to be
733 * valid
734 */
735 for (i = 0, csum = 0; i < 8; i++) {
736 b = bus_space_read_1(t, h, o+16*i);
737 if (i < ETHER_ADDR_LEN)
738 dst[i] = bbr(b);
739 csum ^= b;
740 }
741
742 return csum;
743 }
744