1 /* $NetBSD: if_mc.c,v 1.45 2017/02/22 09:45:16 nonaka Exp $ */ 2 3 /*- 4 * Copyright (c) 1997 David Huang <khym@azeotrope.org> 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: if_mc.c,v 1.45 2017/02/22 09:45:16 nonaka 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 <net/bpf.h> 71 #include <net/bpfdesc.h> 72 73 #include <machine/bus.h> 74 #include <mac68k/dev/if_mcreg.h> 75 #include <mac68k/dev/if_mcvar.h> 76 77 hide void mcwatchdog(struct ifnet *); 78 hide int mcinit(struct mc_softc *); 79 hide int mcstop(struct mc_softc *); 80 hide int mcioctl(struct ifnet *, u_long, void *); 81 hide void mcstart(struct ifnet *); 82 hide void mcreset(struct mc_softc *); 83 84 integrate u_int maceput(struct mc_softc *, struct mbuf *); 85 integrate void mc_tint(struct mc_softc *); 86 integrate void mace_read(struct mc_softc *, void *, int); 87 integrate struct mbuf *mace_get(struct mc_softc *, void *, int); 88 static void mace_calcladrf(struct ethercom *, u_int8_t *); 89 static inline u_int16_t ether_cmp(void *, void *); 90 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 u_int16_t *a = (u_short *) one; 110 u_int16_t *b = (u_short *) two; 111 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, device_xname(sc->sc_dev), 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 if_attach(ifp); 163 if_deferred_start_init(ifp, NULL); 164 ether_ifattach(ifp, lladdr); 165 166 return (0); 167 } 168 169 hide int 170 mcioctl(struct ifnet *ifp, u_long cmd, void *data) 171 { 172 struct mc_softc *sc = ifp->if_softc; 173 struct ifaddr *ifa; 174 175 int s = splnet(), err = 0; 176 177 switch (cmd) { 178 179 case SIOCINITIFADDR: 180 ifa = (struct ifaddr *)data; 181 ifp->if_flags |= IFF_UP; 182 mcinit(sc); 183 switch (ifa->ifa_addr->sa_family) { 184 #ifdef INET 185 case AF_INET: 186 arp_ifinit(ifp, ifa); 187 break; 188 #endif 189 default: 190 break; 191 } 192 break; 193 194 case SIOCSIFFLAGS: 195 if ((err = ifioctl_common(ifp, cmd, data)) != 0) 196 break; 197 /* XXX see the comment in ed_ioctl() about code re-use */ 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 = ether_ioctl(ifp, cmd, data); 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 /* 263 * If bpf is listening on this interface, let it 264 * see the packet before we commit it to the wire. 265 */ 266 bpf_mtap(ifp, m); 267 268 /* 269 * Copy the mbuf chain into the transmit buffer. 270 */ 271 ifp->if_flags |= IFF_OACTIVE; 272 maceput(sc, m); 273 274 ifp->if_opackets++; /* # of pkts */ 275 } 276 } 277 278 /* 279 * reset and restart the MACE. Called in case of fatal 280 * hardware/software errors. 281 */ 282 hide void 283 mcreset(struct mc_softc *sc) 284 { 285 mcstop(sc); 286 mcinit(sc); 287 } 288 289 hide int 290 mcinit(struct mc_softc *sc) 291 { 292 int s; 293 u_int8_t maccc, ladrf[8]; 294 295 if (sc->sc_if.if_flags & IFF_RUNNING) 296 /* already running */ 297 return (0); 298 299 s = splnet(); 300 301 NIC_PUT(sc, MACE_BIUCC, sc->sc_biucc); 302 NIC_PUT(sc, MACE_FIFOCC, sc->sc_fifocc); 303 NIC_PUT(sc, MACE_IMR, ~0); /* disable all interrupts */ 304 NIC_PUT(sc, MACE_PLSCC, sc->sc_plscc); 305 306 NIC_PUT(sc, MACE_UTR, RTRD); /* disable reserved test registers */ 307 308 /* set MAC address */ 309 NIC_PUT(sc, MACE_IAC, ADDRCHG); 310 while (NIC_GET(sc, MACE_IAC) & ADDRCHG) 311 ; 312 NIC_PUT(sc, MACE_IAC, PHYADDR); 313 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_PADR), 314 sc->sc_enaddr, ETHER_ADDR_LEN); 315 316 /* set logical address filter */ 317 mace_calcladrf(&sc->sc_ethercom, ladrf); 318 319 NIC_PUT(sc, MACE_IAC, ADDRCHG); 320 while (NIC_GET(sc, MACE_IAC) & ADDRCHG) 321 ; 322 NIC_PUT(sc, MACE_IAC, LOGADDR); 323 bus_space_write_multi_1(sc->sc_regt, sc->sc_regh, MACE_REG(MACE_LADRF), 324 ladrf, 8); 325 326 NIC_PUT(sc, MACE_XMTFC, APADXMT); 327 /* 328 * No need to autostrip padding on receive... Ethernet frames 329 * don't have a length field, unlike 802.3 frames, so the MACE 330 * can't figure out the length of the packet anyways. 331 */ 332 NIC_PUT(sc, MACE_RCVFC, 0); 333 334 maccc = ENXMT | ENRCV; 335 if (sc->sc_if.if_flags & IFF_PROMISC) 336 maccc |= PROM; 337 338 NIC_PUT(sc, MACE_MACCC, maccc); 339 340 if (sc->sc_bus_init) 341 (*sc->sc_bus_init)(sc); 342 343 /* 344 * Enable all interrupts except receive, since we use the DMA 345 * completion interrupt for that. 346 */ 347 NIC_PUT(sc, MACE_IMR, RCVINTM); 348 349 /* flag interface as "running" */ 350 sc->sc_if.if_flags |= IFF_RUNNING; 351 sc->sc_if.if_flags &= ~IFF_OACTIVE; 352 353 splx(s); 354 return (0); 355 } 356 357 /* 358 * close down an interface and free its buffers 359 * Called on final close of device, or if mcinit() fails 360 * part way through. 361 */ 362 hide int 363 mcstop(struct mc_softc *sc) 364 { 365 int s; 366 367 s = splnet(); 368 369 NIC_PUT(sc, MACE_BIUCC, SWRST); 370 DELAY(100); 371 372 sc->sc_if.if_timer = 0; 373 sc->sc_if.if_flags &= ~IFF_RUNNING; 374 375 splx(s); 376 return (0); 377 } 378 379 /* 380 * Called if any Tx packets remain unsent after 5 seconds, 381 * In all cases we just reset the chip, and any retransmission 382 * will be handled by higher level protocol timeouts. 383 */ 384 hide void 385 mcwatchdog(struct ifnet *ifp) 386 { 387 struct mc_softc *sc = ifp->if_softc; 388 389 printf("mcwatchdog: resetting chip\n"); 390 mcreset(sc); 391 } 392 393 /* 394 * stuff packet into MACE (at splnet) 395 */ 396 integrate u_int 397 maceput(struct mc_softc *sc, struct mbuf *m) 398 { 399 struct mbuf *n; 400 u_int len, totlen = 0; 401 u_char *buff; 402 403 buff = (u_char*)sc->sc_txbuf + (sc->sc_txset == 0 ? 0 : 0x800); 404 405 for (; m; m = n) { 406 u_char *data = mtod(m, u_char *); 407 len = m->m_len; 408 totlen += len; 409 memcpy(buff, data, len); 410 buff += len; 411 n = m_free(m); 412 } 413 414 if (totlen > PAGE_SIZE) 415 panic("%s: maceput: packet overflow", device_xname(sc->sc_dev)); 416 417 #if 0 418 if (totlen < ETHERMIN + sizeof(struct ether_header)) { 419 int pad = ETHERMIN + sizeof(struct ether_header) - totlen; 420 memset(sc->sc_txbuf + totlen, 0, pad); 421 totlen = ETHERMIN + sizeof(struct ether_header); 422 } 423 #endif 424 425 (*sc->sc_putpacket)(sc, totlen); 426 427 sc->sc_if.if_timer = 5; /* 5 seconds to watch for failing to transmit */ 428 return (totlen); 429 } 430 431 void 432 mcintr(void *arg) 433 { 434 struct mc_softc *sc = arg; 435 u_int8_t ir; 436 437 ir = NIC_GET(sc, MACE_IR) & ~NIC_GET(sc, MACE_IMR); 438 if (ir & JAB) { 439 #ifdef MCDEBUG 440 printf("%s: jabber error\n", device_xname(sc->sc_dev)); 441 #endif 442 sc->sc_if.if_oerrors++; 443 } 444 445 if (ir & BABL) { 446 #ifdef MCDEBUG 447 printf("%s: babble\n", device_xname(sc->sc_dev)); 448 #endif 449 sc->sc_if.if_oerrors++; 450 } 451 452 if (ir & CERR) { 453 #ifdef MCDEBUG 454 printf("%s: collision error\n", device_xname(sc->sc_dev)); 455 #endif 456 sc->sc_if.if_collisions++; 457 } 458 459 /* 460 * Pretend we have carrier; if we don't this will be cleared 461 * shortly. 462 */ 463 sc->sc_havecarrier = 1; 464 465 if (ir & XMTINT) 466 mc_tint(sc); 467 468 if (ir & RCVINT) 469 mc_rint(sc); 470 } 471 472 integrate void 473 mc_tint(struct mc_softc *sc) 474 { 475 u_int8_t /* xmtrc,*/ xmtfs; 476 477 /* xmtrc = */ NIC_GET(sc, MACE_XMTRC); 478 xmtfs = NIC_GET(sc, MACE_XMTFS); 479 480 if ((xmtfs & XMTSV) == 0) 481 return; 482 483 if (xmtfs & UFLO) { 484 printf("%s: underflow\n", device_xname(sc->sc_dev)); 485 mcreset(sc); 486 return; 487 } 488 489 if (xmtfs & LCOL) { 490 printf("%s: late collision\n", device_xname(sc->sc_dev)); 491 sc->sc_if.if_oerrors++; 492 sc->sc_if.if_collisions++; 493 } 494 495 if (xmtfs & MORE) 496 /* Real number is unknown. */ 497 sc->sc_if.if_collisions += 2; 498 else if (xmtfs & ONE) 499 sc->sc_if.if_collisions++; 500 else if (xmtfs & RTRY) { 501 printf("%s: excessive collisions\n", device_xname(sc->sc_dev)); 502 sc->sc_if.if_collisions += 16; 503 sc->sc_if.if_oerrors++; 504 } 505 506 if (xmtfs & LCAR) { 507 sc->sc_havecarrier = 0; 508 printf("%s: lost carrier\n", device_xname(sc->sc_dev)); 509 sc->sc_if.if_oerrors++; 510 } 511 512 sc->sc_if.if_flags &= ~IFF_OACTIVE; 513 sc->sc_if.if_timer = 0; 514 if_schedule_deferred_start(&sc->sc_if); 515 } 516 517 void 518 mc_rint(struct mc_softc *sc) 519 { 520 #define rxf sc->sc_rxframe 521 u_int len; 522 523 len = (rxf.rx_rcvcnt | ((rxf.rx_rcvsts & 0xf) << 8)) - 4; 524 525 #ifdef MCDEBUG 526 if (rxf.rx_rcvsts & 0xf0) 527 printf("%s: rcvcnt %02x rcvsts %02x rntpc 0x%02x rcvcc 0x%02x\n", 528 device_xname(sc->sc_dev), rxf.rx_rcvcnt, rxf.rx_rcvsts, 529 rxf.rx_rntpc, rxf.rx_rcvcc); 530 #endif 531 532 if (rxf.rx_rcvsts & OFLO) { 533 printf("%s: receive FIFO overflow\n", device_xname(sc->sc_dev)); 534 sc->sc_if.if_ierrors++; 535 return; 536 } 537 538 if (rxf.rx_rcvsts & CLSN) 539 sc->sc_if.if_collisions++; 540 541 if (rxf.rx_rcvsts & FRAM) { 542 #ifdef MCDEBUG 543 printf("%s: framing error\n", device_xname(sc->sc_dev)); 544 #endif 545 sc->sc_if.if_ierrors++; 546 return; 547 } 548 549 if (rxf.rx_rcvsts & FCS) { 550 #ifdef MCDEBUG 551 printf("%s: frame control checksum error\n", device_xname(sc->sc_dev)); 552 #endif 553 sc->sc_if.if_ierrors++; 554 return; 555 } 556 557 mace_read(sc, rxf.rx_frame, len); 558 #undef rxf 559 } 560 561 integrate void 562 mace_read(struct mc_softc *sc, void *pkt, int len) 563 { 564 struct ifnet *ifp = &sc->sc_if; 565 struct mbuf *m; 566 567 if (len <= sizeof(struct ether_header) || 568 len > ETHERMTU + sizeof(struct ether_header)) { 569 #ifdef MCDEBUG 570 printf("%s: invalid packet size %d; dropping\n", 571 device_xname(sc->sc_dev), len); 572 #endif 573 ifp->if_ierrors++; 574 return; 575 } 576 577 m = mace_get(sc, pkt, len); 578 if (m == NULL) { 579 ifp->if_ierrors++; 580 return; 581 } 582 583 /* Pass the packet up. */ 584 if_percpuq_enqueue(ifp->if_percpuq, m); 585 } 586 587 /* 588 * Pull data off an interface. 589 * Len is length of data, with local net header stripped. 590 * We copy the data into mbufs. When full cluster sized units are present 591 * we copy into clusters. 592 */ 593 integrate struct mbuf * 594 mace_get(struct mc_softc *sc, void *pkt, int totlen) 595 { 596 struct mbuf *m; 597 struct mbuf *top, **mp; 598 int len; 599 600 MGETHDR(m, M_DONTWAIT, MT_DATA); 601 if (m == 0) 602 return (0); 603 m_set_rcvif(m, &sc->sc_if); 604 m->m_pkthdr.len = totlen; 605 len = MHLEN; 606 top = 0; 607 mp = ⊤ 608 609 while (totlen > 0) { 610 if (top) { 611 MGET(m, M_DONTWAIT, MT_DATA); 612 if (m == 0) { 613 m_freem(top); 614 return 0; 615 } 616 len = MLEN; 617 } 618 if (totlen >= MINCLSIZE) { 619 MCLGET(m, M_DONTWAIT); 620 if ((m->m_flags & M_EXT) == 0) { 621 m_free(m); 622 m_freem(top); 623 return 0; 624 } 625 len = MCLBYTES; 626 } 627 m->m_len = len = min(totlen, len); 628 memcpy(mtod(m, void *), pkt, len); 629 pkt = (char*)pkt + len; 630 totlen -= len; 631 *mp = m; 632 mp = &m->m_next; 633 } 634 635 return (top); 636 } 637 638 /* 639 * Go through the list of multicast addresses and calculate the logical 640 * address filter. 641 */ 642 void 643 mace_calcladrf(struct ethercom *ac, u_int8_t *af) 644 { 645 struct ifnet *ifp = &ac->ec_if; 646 struct ether_multi *enm; 647 u_char *cp; 648 u_int32_t crc; 649 static const u_int32_t crctab[] = { 650 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 651 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, 652 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 653 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c 654 }; 655 int len; 656 struct ether_multistep step; 657 658 /* 659 * Set up multicast address filter by passing all multicast addresses 660 * through a crc generator, and then using the high order 6 bits as an 661 * index into the 64 bit logical address filter. The high order bit 662 * selects the word, while the rest of the bits select the bit within 663 * the word. 664 */ 665 666 *((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0; 667 ETHER_FIRST_MULTI(step, ac, enm); 668 while (enm != NULL) { 669 if (ETHER_CMP(enm->enm_addrlo, enm->enm_addrhi)) { 670 /* 671 * We must listen to a range of multicast addresses. 672 * For now, just accept all multicasts, rather than 673 * trying to set only those filter bits needed to match 674 * the range. (At this time, the only use of address 675 * ranges is for IP multicast routing, for which the 676 * range is big enough to require all bits set.) 677 */ 678 goto allmulti; 679 } 680 681 cp = enm->enm_addrlo; 682 crc = 0xffffffff; 683 for (len = sizeof(enm->enm_addrlo); --len >= 0;) { 684 crc ^= *cp++; 685 crc = (crc >> 4) ^ crctab[crc & 0xf]; 686 crc = (crc >> 4) ^ crctab[crc & 0xf]; 687 } 688 /* Just want the 6 most significant bits. */ 689 crc >>= 26; 690 691 /* Set the corresponding bit in the filter. */ 692 af[crc >> 3] |= 1 << (crc & 7); 693 694 ETHER_NEXT_MULTI(step, enm); 695 } 696 ifp->if_flags &= ~IFF_ALLMULTI; 697 return; 698 699 allmulti: 700 ifp->if_flags |= IFF_ALLMULTI; 701 *((u_int32_t *)af) = *((u_int32_t *)af + 1) = 0xffffffff; 702 } 703 704 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15}; 705 #define bbr(v) ((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf]) 706 707 u_char 708 mc_get_enaddr(bus_space_tag_t t, bus_space_handle_t h, bus_size_t o, 709 u_char *dst) 710 { 711 int i; 712 u_char b, csum; 713 714 /* 715 * The XOR of the 8 bytes of the ROM must be 0xff for it to be 716 * valid 717 */ 718 for (i = 0, csum = 0; i < 8; i++) { 719 b = bus_space_read_1(t, h, o+16*i); 720 if (i < ETHER_ADDR_LEN) 721 dst[i] = bbr(b); 722 csum ^= b; 723 } 724 725 return csum; 726 } 727