Home | History | Annotate | Line # | Download | only in dev
if_sn.c revision 1.33
      1 /*	$NetBSD: if_sn.c,v 1.33 2003/04/02 00:44:23 thorpej Exp $	*/
      2 
      3 /*
      4  * National Semiconductor  DP8393X SONIC Driver
      5  * Copyright (c) 1991   Algorithmics Ltd (http://www.algor.co.uk)
      6  * You may use, copy, and modify this program so long as you retain the
      7  * copyright line.
      8  *
      9  * This driver has been substantially modified since Algorithmics donated
     10  * it.
     11  *
     12  *   Denton Gentry <denny1 (at) home.com>
     13  * and also
     14  *   Yanagisawa Takeshi <yanagisw (at) aa.ap.titech.ac.jp>
     15  * did the work to get this running on the Macintosh.
     16  */
     17 
     18 #include "opt_inet.h"
     19 
     20 #include <sys/param.h>
     21 #include <sys/systm.h>
     22 #include <sys/mbuf.h>
     23 #include <sys/buf.h>
     24 #include <sys/protosw.h>
     25 #include <sys/socket.h>
     26 #include <sys/syslog.h>
     27 #include <sys/ioctl.h>
     28 #include <sys/errno.h>
     29 #include <sys/device.h>
     30 
     31 #include <uvm/uvm_extern.h>
     32 
     33 #include <net/if.h>
     34 #include <net/if_dl.h>
     35 #include <net/if_ether.h>
     36 
     37 #ifdef INET
     38 #include <netinet/in.h>
     39 #include <netinet/in_systm.h>
     40 #include <netinet/in_var.h>
     41 #include <netinet/ip.h>
     42 #include <netinet/if_inarp.h>
     43 #endif
     44 
     45 #include <uvm/uvm_extern.h>
     46 
     47 #include "bpfilter.h"
     48 #if NBPFILTER > 0
     49 #include <net/bpf.h>
     50 #include <net/bpfdesc.h>
     51 #endif
     52 
     53 #include <machine/bus.h>
     54 #include <machine/cpu.h>
     55 #include <machine/viareg.h>
     56 #include <mac68k/dev/if_snreg.h>
     57 #include <mac68k/dev/if_snvar.h>
     58 
     59 static void	snwatchdog __P((struct ifnet *));
     60 static int	sninit __P((struct sn_softc *sc));
     61 static int	snstop __P((struct sn_softc *sc));
     62 static int	snioctl __P((struct ifnet *ifp, u_long cmd, caddr_t data));
     63 static void	snstart __P((struct ifnet *ifp));
     64 static void	snreset __P((struct sn_softc *sc));
     65 
     66 static void	caminitialise __P((struct sn_softc *));
     67 static void	camentry __P((struct sn_softc *, int, u_char *ea));
     68 static void	camprogram __P((struct sn_softc *));
     69 static void	initialise_tda __P((struct sn_softc *));
     70 static void	initialise_rda __P((struct sn_softc *));
     71 static void	initialise_rra __P((struct sn_softc *));
     72 #ifdef SNDEBUG
     73 static void	camdump __P((struct sn_softc *sc));
     74 #endif
     75 
     76 static void	sonictxint __P((struct sn_softc *));
     77 static void	sonicrxint __P((struct sn_softc *));
     78 
     79 static __inline__ u_int	sonicput __P((struct sn_softc *sc, struct mbuf *m0,
     80 			    int mtd_next));
     81 static __inline__ int	sonic_read __P((struct sn_softc *, caddr_t, int));
     82 static __inline__ struct mbuf *sonic_get __P((struct sn_softc *, caddr_t, int));
     83 
     84 #undef assert
     85 #undef _assert
     86 
     87 #ifdef NDEBUG
     88 #define	assert(e)	((void)0)
     89 #define	_assert(e)	((void)0)
     90 #else
     91 #define	_assert(e)	assert(e)
     92 #ifdef __STDC__
     93 #define	assert(e)	((e) ? (void)0 : __assert("sn ", __FILE__, __LINE__, #e))
     94 #else	/* PCC */
     95 #define	assert(e)	((e) ? (void)0 : __assert("sn "__FILE__, __LINE__, "e"))
     96 #endif
     97 #endif
     98 
     99 int sndebug = 0;
    100 
    101 /*
    102  * SONIC buffers need to be aligned 16 or 32 bit aligned.
    103  * These macros calculate and verify alignment.
    104  */
    105 #define	ROUNDUP(p, N)	(((int) p + N - 1) & ~(N - 1))
    106 
    107 #define SOALIGN(m, array)	(m ? (ROUNDUP(array, 4)) : (ROUNDUP(array, 2)))
    108 
    109 #define LOWER(x) ((unsigned)(x) & 0xffff)
    110 #define UPPER(x) ((unsigned)(x) >> 16)
    111 
    112 /*
    113  * Interface exists: make available by filling in network interface
    114  * record.  System will initialize the interface when it is ready
    115  * to accept packets.
    116  */
    117 int
    118 snsetup(sc, lladdr)
    119 	struct sn_softc	*sc;
    120 	u_int8_t *lladdr;
    121 {
    122 	struct ifnet *ifp = &sc->sc_if;
    123 	u_char	*p;
    124 	u_char	*pp;
    125 	int	i;
    126 	int	offset;
    127 
    128 	/*
    129 	 * XXX if_sn.c is intended to be MI. Should it allocate memory
    130 	 * for its descriptor areas, or expect the MD attach code
    131 	 * to do that?
    132 	 */
    133 	sc->space = malloc((SN_NPAGES + 1) * PAGE_SIZE, M_DEVBUF, M_WAITOK);
    134 	if (sc->space == NULL) {
    135 		printf ("%s: memory allocation for descriptors failed\n",
    136 		    sc->sc_dev.dv_xname);
    137 		return (1);
    138 	}
    139 
    140 	/*
    141 	 * Put the pup in reset mode (sninit() will fix it later),
    142 	 * stop the timer, disable all interrupts and clear any interrupts.
    143 	 */
    144 	NIC_PUT(sc, SNR_CR, CR_STP);
    145 	wbflush();
    146 	NIC_PUT(sc, SNR_CR, CR_RST);
    147 	wbflush();
    148 	NIC_PUT(sc, SNR_IMR, 0);
    149 	wbflush();
    150 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    151 	wbflush();
    152 
    153 	/*
    154 	 * because the SONIC is basically 16bit device it 'concatenates'
    155 	 * a higher buffer address to a 16 bit offset--this will cause wrap
    156 	 * around problems near the end of 64k !!
    157 	 */
    158 	p = sc->space;
    159 	pp = (u_char *)ROUNDUP ((int)p, PAGE_SIZE);
    160 	p = pp;
    161 
    162 	/*
    163 	 * Disable caching on the SONIC's data space.
    164 	 * The pages might not be physically contiguous, so set
    165 	 * each page individually.
    166 	 */
    167 	for (i = 0; i < SN_NPAGES; i++) {
    168 		physaccess (p, (caddr_t)SONIC_GETDMA(p), PAGE_SIZE,
    169 		    PG_V | PG_RW | PG_CI);
    170 		p += PAGE_SIZE;
    171 	}
    172 	p = pp;
    173 
    174 	for (i = 0; i < NRRA; i++) {
    175 		sc->p_rra[i] = (void *)p;
    176 		sc->v_rra[i] = SONIC_GETDMA(p);
    177 		p += RXRSRC_SIZE(sc);
    178 	}
    179 	sc->v_rea = SONIC_GETDMA(p);
    180 
    181 	p = (u_char *)SOALIGN(sc, p);
    182 
    183 	sc->p_cda = (void *)(p);
    184 	sc->v_cda = SONIC_GETDMA(p);
    185 	p += CDA_SIZE(sc);
    186 
    187 	p = (u_char *)SOALIGN(sc, p);
    188 
    189 	for (i = 0; i < NTDA; i++) {
    190 		struct mtd *mtdp = &sc->mtda[i];
    191 		mtdp->mtd_txp = (void *)p;
    192 		mtdp->mtd_vtxp = SONIC_GETDMA(p);
    193 		p += TXP_SIZE(sc);
    194 	}
    195 
    196 	p = (u_char *)SOALIGN(sc, p);
    197 
    198 	if ((p - pp) > PAGE_SIZE) {
    199 		printf ("%s: sizeof RRA (%ld) + CDA (%ld) +"
    200 		    "TDA (%ld) > PAGE_SIZE (%d). Punt!\n",
    201 		    sc->sc_dev.dv_xname,
    202 		    (ulong)sc->p_cda - (ulong)sc->p_rra[0],
    203 		    (ulong)sc->mtda[0].mtd_txp - (ulong)sc->p_cda,
    204 		    (ulong)p - (ulong)sc->mtda[0].mtd_txp,
    205 		    PAGE_SIZE);
    206 		return(1);
    207 	}
    208 
    209 	p = pp + PAGE_SIZE;
    210 	pp = p;
    211 
    212 	sc->sc_nrda = PAGE_SIZE / RXPKT_SIZE(sc);
    213 	sc->p_rda = (caddr_t) p;
    214 	sc->v_rda = SONIC_GETDMA(p);
    215 
    216 	p = pp + PAGE_SIZE;
    217 
    218 	for (i = 0; i < NRBA; i++) {
    219 		sc->rbuf[i] = (caddr_t)p;
    220 		p += PAGE_SIZE;
    221 	}
    222 
    223 	pp = p;
    224 	offset = TXBSIZE;
    225 	for (i = 0; i < NTDA; i++) {
    226 		struct mtd *mtdp = &sc->mtda[i];
    227 
    228 		mtdp->mtd_buf = p;
    229 		mtdp->mtd_vbuf = SONIC_GETDMA(p);
    230 		offset += TXBSIZE;
    231 		if (offset < PAGE_SIZE) {
    232 			p += TXBSIZE;
    233 		} else {
    234 			p = pp + PAGE_SIZE;
    235 			pp = p;
    236 			offset = TXBSIZE;
    237 		}
    238 	}
    239 
    240 #ifdef SNDEBUG
    241 	camdump(sc);
    242 #endif
    243 	printf("%s: Ethernet address %s\n",
    244 	    sc->sc_dev.dv_xname, ether_sprintf(lladdr));
    245 
    246 #ifdef SNDEBUG
    247 	printf("%s: buffers: rra=%p cda=%p rda=%p tda=%p\n",
    248 	    sc->sc_dev.dv_xname, sc->p_rra[0], sc->p_cda,
    249 	    sc->p_rda, sc->mtda[0].mtd_txp);
    250 #endif
    251 
    252 	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
    253 	ifp->if_softc = sc;
    254 	ifp->if_ioctl = snioctl;
    255 	ifp->if_start = snstart;
    256 	ifp->if_flags =
    257 	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
    258 	ifp->if_watchdog = snwatchdog;
    259 
    260 	if_attach(ifp);
    261 	ether_ifattach(ifp, lladdr);
    262 
    263 	return (0);
    264 }
    265 
    266 static int
    267 snioctl(ifp, cmd, data)
    268 	struct ifnet *ifp;
    269 	u_long cmd;
    270 	caddr_t data;
    271 {
    272 	struct ifaddr *ifa;
    273 	struct ifreq *ifr;
    274 	struct sn_softc *sc = ifp->if_softc;
    275 	int	s = splnet(), err = 0;
    276 	int	temp;
    277 
    278 	switch (cmd) {
    279 
    280 	case SIOCSIFADDR:
    281 		ifa = (struct ifaddr *)data;
    282 		ifp->if_flags |= IFF_UP;
    283 		switch (ifa->ifa_addr->sa_family) {
    284 #ifdef INET
    285 		case AF_INET:
    286 			(void)sninit(sc);
    287 			arp_ifinit(ifp, ifa);
    288 			break;
    289 #endif
    290 		default:
    291 			(void)sninit(sc);
    292 			break;
    293 		}
    294 		break;
    295 
    296 	case SIOCSIFFLAGS:
    297 		if ((ifp->if_flags & IFF_UP) == 0 &&
    298 		    (ifp->if_flags & IFF_RUNNING) != 0) {
    299 			/*
    300 			 * If interface is marked down and it is running,
    301 			 * then stop it.
    302 			 */
    303 			snstop(sc);
    304 			ifp->if_flags &= ~IFF_RUNNING;
    305 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
    306 		    (ifp->if_flags & IFF_RUNNING) == 0) {
    307 			/*
    308 			 * If interface is marked up and it is stopped,
    309 			 * then start it.
    310 			 */
    311 			(void)sninit(sc);
    312 		} else {
    313 			/*
    314 			 * reset the interface to pick up any other changes
    315 			 * in flags
    316 			 */
    317 			temp = ifp->if_flags & IFF_UP;
    318 			snreset(sc);
    319 			ifp->if_flags |= temp;
    320 			snstart(ifp);
    321 		}
    322 		break;
    323 
    324 	case SIOCADDMULTI:
    325 	case SIOCDELMULTI:
    326 		ifr = (struct ifreq *) data;
    327 		if (cmd == SIOCADDMULTI)
    328 			err = ether_addmulti(ifr, &sc->sc_ethercom);
    329 		else
    330 			err = ether_delmulti(ifr, &sc->sc_ethercom);
    331 
    332 		if (err == ENETRESET) {
    333 			/*
    334 			 * Multicast list has changed; set the hardware
    335 			 * filter accordingly. But remember UP flag!
    336 			 */
    337 			temp = ifp->if_flags & IFF_UP;
    338 			snreset(sc);
    339 			ifp->if_flags |= temp;
    340 			err = 0;
    341 		}
    342 		break;
    343 	default:
    344 		err = EINVAL;
    345 	}
    346 	splx(s);
    347 	return (err);
    348 }
    349 
    350 /*
    351  * Encapsulate a packet of type family for the local net.
    352  */
    353 static void
    354 snstart(ifp)
    355 	struct ifnet *ifp;
    356 {
    357 	struct sn_softc	*sc = ifp->if_softc;
    358 	struct mbuf	*m;
    359 	int		mtd_next;
    360 
    361 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
    362 		return;
    363 
    364 outloop:
    365 	/* Check for room in the xmit buffer. */
    366 	if ((mtd_next = (sc->mtd_free + 1)) == NTDA)
    367 		mtd_next = 0;
    368 
    369 	if (mtd_next == sc->mtd_hw) {
    370 		ifp->if_flags |= IFF_OACTIVE;
    371 		return;
    372 	}
    373 
    374 	IF_DEQUEUE(&ifp->if_snd, m);
    375 	if (m == 0)
    376 		return;
    377 
    378 	/* We need the header for m_pkthdr.len. */
    379 	if ((m->m_flags & M_PKTHDR) == 0)
    380 		panic("%s: snstart: no header mbuf", sc->sc_dev.dv_xname);
    381 
    382 #if NBPFILTER > 0
    383 	/*
    384 	 * If bpf is listening on this interface, let it
    385 	 * see the packet before we commit it to the wire.
    386 	 */
    387 	if (ifp->if_bpf)
    388 		bpf_mtap(ifp->if_bpf, m);
    389 #endif
    390 
    391 	/*
    392 	 * If there is nothing in the o/p queue, and there is room in
    393 	 * the Tx ring, then send the packet directly.  Otherwise append
    394 	 * it to the o/p queue.
    395 	 */
    396 	if ((sonicput(sc, m, mtd_next)) == 0) {
    397 		IF_PREPEND(&ifp->if_snd, m);
    398 		return;
    399 	}
    400 
    401 	sc->mtd_prev = sc->mtd_free;
    402 	sc->mtd_free = mtd_next;
    403 
    404 	ifp->if_opackets++;		/* # of pkts */
    405 
    406 	/* Jump back for possibly more punishment. */
    407 	goto outloop;
    408 }
    409 
    410 /*
    411  * reset and restart the SONIC.  Called in case of fatal
    412  * hardware/software errors.
    413  */
    414 static void
    415 snreset(sc)
    416 	struct sn_softc *sc;
    417 {
    418 	snstop(sc);
    419 	sninit(sc);
    420 }
    421 
    422 static int
    423 sninit(sc)
    424 	struct sn_softc *sc;
    425 {
    426 	u_long	s_rcr;
    427 	int	s;
    428 
    429 	if (sc->sc_if.if_flags & IFF_RUNNING)
    430 		/* already running */
    431 		return (0);
    432 
    433 	s = splnet();
    434 
    435 	NIC_PUT(sc, SNR_CR, CR_RST);	/* DCR only accessible in reset mode! */
    436 
    437 	/* config it */
    438 	NIC_PUT(sc, SNR_DCR, (sc->snr_dcr |
    439 		(sc->bitmode ? DCR_DW32 : DCR_DW16)));
    440 	NIC_PUT(sc, SNR_DCR2, sc->snr_dcr2);
    441 
    442 	s_rcr = RCR_BRD | RCR_LBNONE;
    443 	if (sc->sc_if.if_flags & IFF_PROMISC)
    444 		s_rcr |= RCR_PRO;
    445 	if (sc->sc_if.if_flags & IFF_ALLMULTI)
    446 		s_rcr |= RCR_AMC;
    447 	NIC_PUT(sc, SNR_RCR, s_rcr);
    448 
    449 	NIC_PUT(sc, SNR_IMR, (IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN));
    450 
    451 	/* clear pending interrupts */
    452 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    453 
    454 	/* clear tally counters */
    455 	NIC_PUT(sc, SNR_CRCT, -1);
    456 	NIC_PUT(sc, SNR_FAET, -1);
    457 	NIC_PUT(sc, SNR_MPT, -1);
    458 
    459 	initialise_tda(sc);
    460 	initialise_rda(sc);
    461 	initialise_rra(sc);
    462 
    463 	/* enable the chip */
    464 	NIC_PUT(sc, SNR_CR, 0);
    465 	wbflush();
    466 
    467 	/* program the CAM */
    468 	camprogram(sc);
    469 
    470 	/* get it to read resource descriptors */
    471 	NIC_PUT(sc, SNR_CR, CR_RRRA);
    472 	wbflush();
    473 	while ((NIC_GET(sc, SNR_CR)) & CR_RRRA)
    474 		continue;
    475 
    476 	/* enable rx */
    477 	NIC_PUT(sc, SNR_CR, CR_RXEN);
    478 	wbflush();
    479 
    480 	/* flag interface as "running" */
    481 	sc->sc_if.if_flags |= IFF_RUNNING;
    482 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
    483 
    484 	splx(s);
    485 	return (0);
    486 }
    487 
    488 /*
    489  * close down an interface and free its buffers
    490  * Called on final close of device, or if sninit() fails
    491  * part way through.
    492  */
    493 static int
    494 snstop(sc)
    495 	struct sn_softc *sc;
    496 {
    497 	struct mtd *mtd;
    498 	int	s = splnet();
    499 
    500 	/* stick chip in reset */
    501 	NIC_PUT(sc, SNR_CR, CR_RST);
    502 	wbflush();
    503 
    504 	/* free all receive buffers (currently static so nothing to do) */
    505 
    506 	/* free all pending transmit mbufs */
    507 	while (sc->mtd_hw != sc->mtd_free) {
    508 		mtd = &sc->mtda[sc->mtd_hw];
    509 		if (mtd->mtd_mbuf)
    510 			m_freem(mtd->mtd_mbuf);
    511 		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
    512 	}
    513 
    514 	sc->sc_if.if_timer = 0;
    515 	sc->sc_if.if_flags &= ~(IFF_RUNNING | IFF_UP);
    516 
    517 	splx(s);
    518 	return (0);
    519 }
    520 
    521 /*
    522  * Called if any Tx packets remain unsent after 5 seconds,
    523  * In all cases we just reset the chip, and any retransmission
    524  * will be handled by higher level protocol timeouts.
    525  */
    526 static void
    527 snwatchdog(ifp)
    528 	struct ifnet *ifp;
    529 {
    530 	struct sn_softc *sc = ifp->if_softc;
    531 	struct mtd *mtd;
    532 	int	temp;
    533 
    534 	if (sc->mtd_hw != sc->mtd_free) {
    535 		/* something still pending for transmit */
    536 		mtd = &sc->mtda[sc->mtd_hw];
    537 		if (SRO(sc->bitmode, mtd->mtd_txp, TXP_STATUS) == 0)
    538 			log(LOG_ERR, "%s: Tx - timeout\n",
    539 			    sc->sc_dev.dv_xname);
    540 		else
    541 			log(LOG_ERR, "%s: Tx - lost interrupt\n",
    542 			    sc->sc_dev.dv_xname);
    543 		temp = ifp->if_flags & IFF_UP;
    544 		snreset(sc);
    545 		ifp->if_flags |= temp;
    546 	}
    547 }
    548 
    549 /*
    550  * stuff packet into sonic (at splnet)
    551  */
    552 static __inline__ u_int
    553 sonicput(sc, m0, mtd_next)
    554 	struct sn_softc *sc;
    555 	struct mbuf *m0;
    556 	int mtd_next;
    557 {
    558 	struct mtd *mtdp;
    559 	struct mbuf *m;
    560 	u_char	*buff;
    561 	void	*txp;
    562 	u_int	len = 0;
    563 	u_int	totlen = 0;
    564 
    565 #ifdef whyonearthwouldyoudothis
    566 	if (NIC_GET(sc, SNR_CR) & CR_TXP)
    567 		return (0);
    568 #endif
    569 
    570 	/* grab the replacement mtd */
    571 	mtdp = &sc->mtda[sc->mtd_free];
    572 
    573 	buff = mtdp->mtd_buf;
    574 
    575 	/* this packet goes to mtdnext fill in the TDA */
    576 	mtdp->mtd_mbuf = m0;
    577 	txp = mtdp->mtd_txp;
    578 
    579 	/* Write to the config word. Every (NTDA/2)+1 packets we set an intr */
    580 	if (sc->mtd_pint == 0) {
    581 		sc->mtd_pint = NTDA/2;
    582 		SWO(sc->bitmode, txp, TXP_CONFIG, TCR_PINT);
    583 	} else {
    584 		sc->mtd_pint--;
    585 		SWO(sc->bitmode, txp, TXP_CONFIG, 0);
    586 	}
    587 
    588 	for (m = m0; m; m = m->m_next) {
    589 		u_char *data = mtod(m, u_char *);
    590 		len = m->m_len;
    591 		totlen += len;
    592 		bcopy(data, buff, len);
    593 		buff += len;
    594 	}
    595 	if (totlen >= TXBSIZE) {
    596 		panic("%s: sonicput: packet overflow", sc->sc_dev.dv_xname);
    597 	}
    598 
    599 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRLO,
    600 	    LOWER(mtdp->mtd_vbuf));
    601 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRHI,
    602 	    UPPER(mtdp->mtd_vbuf));
    603 
    604 	if (totlen < ETHERMIN + ETHER_HDR_LEN) {
    605 		int pad = ETHERMIN + ETHER_HDR_LEN - totlen;
    606 		bzero(mtdp->mtd_buf + totlen, pad);
    607 		totlen = ETHERMIN + ETHER_HDR_LEN;
    608 	}
    609 
    610 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FSIZE,
    611 	    totlen);
    612 	SWO(sc->bitmode, txp, TXP_FRAGCNT, 1);
    613 	SWO(sc->bitmode, txp, TXP_PKTSIZE, totlen);
    614 
    615 	/* link onto the next mtd that will be used */
    616 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (1 * TXP_FRAGSIZE) + TXP_FPTRLO,
    617 	    LOWER(sc->mtda[mtd_next].mtd_vtxp) | EOL);
    618 
    619 	/*
    620 	 * The previous txp.tlink currently contains a pointer to
    621 	 * our txp | EOL. Want to clear the EOL, so write our
    622 	 * pointer to the previous txp.
    623 	 */
    624 	SWO(sc->bitmode, sc->mtda[sc->mtd_prev].mtd_txp, sc->mtd_tlinko,
    625 	    LOWER(mtdp->mtd_vtxp));
    626 
    627 	/* make sure chip is running */
    628 	wbflush();
    629 	NIC_PUT(sc, SNR_CR, CR_TXP);
    630 	wbflush();
    631 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
    632 
    633 	return (totlen);
    634 }
    635 
    636 /*
    637  * These are called from sonicioctl() when /etc/ifconfig is run to set
    638  * the address or switch the i/f on.
    639  */
    640 /*
    641  * CAM support
    642  */
    643 static void
    644 caminitialise(sc)
    645 	struct sn_softc *sc;
    646 {
    647 	void	*p_cda = sc->p_cda;
    648 	int	i;
    649 	int	bitmode = sc->bitmode;
    650 	int	camoffset;
    651 
    652 	for (i = 0; i < MAXCAM; i++) {
    653 		camoffset = i * CDA_CAMDESC;
    654 		SWO(bitmode, p_cda, (camoffset + CDA_CAMEP), i);
    655 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP2), 0);
    656 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP1), 0);
    657 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP0), 0);
    658 	}
    659 	SWO(bitmode, p_cda, CDA_ENABLE, 0);
    660 }
    661 
    662 static void
    663 camentry(sc, entry, ea)
    664 	int entry;
    665 	u_char *ea;
    666 	struct sn_softc *sc;
    667 {
    668 	void	*p_cda = sc->p_cda;
    669 	int	bitmode = sc->bitmode;
    670 	int	camoffset = entry * CDA_CAMDESC;
    671 
    672 	SWO(bitmode, p_cda, camoffset + CDA_CAMEP, entry);
    673 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP2, (ea[5] << 8) | ea[4]);
    674 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP1, (ea[3] << 8) | ea[2]);
    675 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP0, (ea[1] << 8) | ea[0]);
    676 	SWO(bitmode, p_cda, CDA_ENABLE,
    677 	    (SRO(bitmode, p_cda, CDA_ENABLE) | (1 << entry)));
    678 }
    679 
    680 static void
    681 camprogram(sc)
    682 	struct sn_softc *sc;
    683 {
    684 	struct ether_multistep step;
    685 	struct ether_multi *enm;
    686 	struct ifnet *ifp;
    687 	int	timeout;
    688 	int	mcount = 0;
    689 
    690 	caminitialise(sc);
    691 
    692 	ifp = &sc->sc_if;
    693 
    694 	/* Always load our own address first. */
    695 	camentry (sc, mcount, LLADDR(ifp->if_sadl));
    696 	mcount++;
    697 
    698 	/* Assume we won't need allmulti bit. */
    699 	ifp->if_flags &= ~IFF_ALLMULTI;
    700 
    701 	/* Loop through multicast addresses */
    702 	ETHER_FIRST_MULTI(step, &sc->sc_ethercom, enm);
    703 	while (enm != NULL) {
    704 		if (mcount == MAXCAM) {
    705 			 ifp->if_flags |= IFF_ALLMULTI;
    706 			 break;
    707 		}
    708 
    709 		if (bcmp(enm->enm_addrlo, enm->enm_addrhi,
    710 		    sizeof(enm->enm_addrlo)) != 0) {
    711 			/*
    712 			 * SONIC's CAM is programmed with specific
    713 			 * addresses. It has no way to specify a range.
    714 			 * (Well, thats not exactly true. If the
    715 			 * range is small one could program each addr
    716 			 * within the range as a separate CAM entry)
    717 			 */
    718 			ifp->if_flags |= IFF_ALLMULTI;
    719 			break;
    720 		}
    721 
    722 		/* program the CAM with the specified entry */
    723 		camentry(sc, mcount, enm->enm_addrlo);
    724 		mcount++;
    725 
    726 		ETHER_NEXT_MULTI(step, enm);
    727 	}
    728 
    729 	NIC_PUT(sc, SNR_CDP, LOWER(sc->v_cda));
    730 	NIC_PUT(sc, SNR_CDC, MAXCAM);
    731 	NIC_PUT(sc, SNR_CR, CR_LCAM);
    732 	wbflush();
    733 
    734 	timeout = 10000;
    735 	while ((NIC_GET(sc, SNR_CR) & CR_LCAM) && timeout--)
    736 		continue;
    737 	if (timeout == 0) {
    738 		/* XXX */
    739 		panic("%s: CAM initialisation failed", sc->sc_dev.dv_xname);
    740 	}
    741 	timeout = 10000;
    742 	while (((NIC_GET(sc, SNR_ISR) & ISR_LCD) == 0) && timeout--)
    743 		continue;
    744 
    745 	if (NIC_GET(sc, SNR_ISR) & ISR_LCD)
    746 		NIC_PUT(sc, SNR_ISR, ISR_LCD);
    747 	else
    748 		printf("%s: CAM initialisation without interrupt\n",
    749 		    sc->sc_dev.dv_xname);
    750 }
    751 
    752 #ifdef SNDEBUG
    753 static void
    754 camdump(sc)
    755 	struct sn_softc *sc;
    756 {
    757 	int	i;
    758 
    759 	printf("CAM entries:\n");
    760 	NIC_PUT(sc, SNR_CR, CR_RST);
    761 	wbflush();
    762 
    763 	for (i = 0; i < 16; i++) {
    764 		ushort  ap2, ap1, ap0;
    765 		NIC_PUT(sc, SNR_CEP, i);
    766 		wbflush();
    767 		ap2 = NIC_GET(sc, SNR_CAP2);
    768 		ap1 = NIC_GET(sc, SNR_CAP1);
    769 		ap0 = NIC_GET(sc, SNR_CAP0);
    770 		printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
    771 	}
    772 	printf("CAM enable 0x%x\n", NIC_GET(sc, SNR_CEP));
    773 
    774 	NIC_PUT(sc, SNR_CR, 0);
    775 	wbflush();
    776 }
    777 #endif
    778 
    779 static void
    780 initialise_tda(sc)
    781 	struct sn_softc *sc;
    782 {
    783 	struct mtd *mtd;
    784 	int	i;
    785 
    786 	for (i = 0; i < NTDA; i++) {
    787 		mtd = &sc->mtda[i];
    788 		mtd->mtd_mbuf = 0;
    789 	}
    790 
    791 	sc->mtd_hw = 0;
    792 	sc->mtd_prev = NTDA - 1;
    793 	sc->mtd_free = 0;
    794 	sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;
    795 	sc->mtd_pint = NTDA/2;
    796 
    797 	NIC_PUT(sc, SNR_UTDA, UPPER(sc->mtda[0].mtd_vtxp));
    798 	NIC_PUT(sc, SNR_CTDA, LOWER(sc->mtda[0].mtd_vtxp));
    799 }
    800 
    801 static void
    802 initialise_rda(sc)
    803 	struct sn_softc *sc;
    804 {
    805 	int		bitmode = sc->bitmode;
    806 	int		i;
    807 	caddr_t		p_rda = 0;
    808 	u_int32_t	v_rda = 0;
    809 
    810 	/* link the RDA's together into a circular list */
    811 	for (i = 0; i < (sc->sc_nrda - 1); i++) {
    812 		p_rda = sc->p_rda + (i * RXPKT_SIZE(sc));
    813 		v_rda = sc->v_rda + ((i+1) * RXPKT_SIZE(sc));
    814 		SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(v_rda));
    815 		SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    816 	}
    817 	p_rda = sc->p_rda + ((sc->sc_nrda - 1) * RXPKT_SIZE(sc));
    818 	SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(sc->v_rda) | EOL);
    819 	SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    820 
    821 	/* mark end of receive descriptor list */
    822 	sc->sc_rdamark = sc->sc_nrda - 1;
    823 
    824 	sc->sc_rxmark = 0;
    825 
    826 	NIC_PUT(sc, SNR_URDA, UPPER(sc->v_rda));
    827 	NIC_PUT(sc, SNR_CRDA, LOWER(sc->v_rda));
    828 	wbflush();
    829 }
    830 
    831 static void
    832 initialise_rra(sc)
    833 	struct sn_softc *sc;
    834 {
    835 	int	i;
    836 	u_int	v;
    837 	int	bitmode = sc->bitmode;
    838 
    839 	if (bitmode)
    840 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 2);
    841 	else
    842 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 1);
    843 
    844 	NIC_PUT(sc, SNR_URRA, UPPER(sc->v_rra[0]));
    845 	NIC_PUT(sc, SNR_RSA, LOWER(sc->v_rra[0]));
    846 	/* rea must point just past the end of the rra space */
    847 	NIC_PUT(sc, SNR_REA, LOWER(sc->v_rea));
    848 	NIC_PUT(sc, SNR_RRP, LOWER(sc->v_rra[0]));
    849 	NIC_PUT(sc, SNR_RSC, 0);
    850 
    851 	/* fill up SOME of the rra with buffers */
    852 	for (i = 0; i < NRBA; i++) {
    853 		v = SONIC_GETDMA(sc->rbuf[i]);
    854 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRHI, UPPER(v));
    855 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRLO, LOWER(v));
    856 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCHI, UPPER(PAGE_SIZE/2));
    857 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCLO, LOWER(PAGE_SIZE/2));
    858 	}
    859 	sc->sc_rramark = NRBA;
    860 	NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[sc->sc_rramark]));
    861 	wbflush();
    862 }
    863 
    864 void
    865 snintr(arg)
    866 	void	*arg;
    867 {
    868 	struct sn_softc *sc = (struct sn_softc *)arg;
    869 	int	isr;
    870 
    871 	while ((isr = (NIC_GET(sc, SNR_ISR) & ISR_ALL)) != 0) {
    872 		/* scrub the interrupts that we are going to service */
    873 		NIC_PUT(sc, SNR_ISR, isr);
    874 		wbflush();
    875 
    876 		if (isr & (ISR_BR | ISR_LCD | ISR_TC))
    877 			printf("%s: unexpected interrupt status 0x%x\n",
    878 			    sc->sc_dev.dv_xname, isr);
    879 
    880 		if (isr & (ISR_TXDN | ISR_TXER | ISR_PINT))
    881 			sonictxint(sc);
    882 
    883 		if (isr & ISR_PKTRX)
    884 			sonicrxint(sc);
    885 
    886 		if (isr & (ISR_HBL | ISR_RDE | ISR_RBE | ISR_RBAE | ISR_RFO)) {
    887 			if (isr & ISR_HBL)
    888 				/*
    889 				 * The repeater is not providing a heartbeat.
    890 				 * In itself this isn't harmful, lots of the
    891 				 * cheap repeater hubs don't supply a heartbeat.
    892 				 * So ignore the lack of heartbeat. Its only
    893 				 * if we can't detect a carrier that we have a
    894 				 * problem.
    895 				 */
    896 				;
    897 			if (isr & ISR_RDE)
    898 				printf("%s: receive descriptors exhausted\n",
    899 				    sc->sc_dev.dv_xname);
    900 			if (isr & ISR_RBE)
    901 				printf("%s: receive buffers exhausted\n",
    902 				    sc->sc_dev.dv_xname);
    903 			if (isr & ISR_RBAE)
    904 				printf("%s: receive buffer area exhausted\n",
    905 				    sc->sc_dev.dv_xname);
    906 			if (isr & ISR_RFO)
    907 				printf("%s: receive FIFO overrun\n",
    908 				    sc->sc_dev.dv_xname);
    909 		}
    910 		if (isr & (ISR_CRC | ISR_FAE | ISR_MP)) {
    911 #ifdef notdef
    912 			if (isr & ISR_CRC)
    913 				sc->sc_crctally++;
    914 			if (isr & ISR_FAE)
    915 				sc->sc_faetally++;
    916 			if (isr & ISR_MP)
    917 				sc->sc_mptally++;
    918 #endif
    919 		}
    920 		snstart(&sc->sc_if);
    921 	}
    922 	return;
    923 }
    924 
    925 /*
    926  * Transmit interrupt routine
    927  */
    928 static void
    929 sonictxint(sc)
    930 	struct sn_softc *sc;
    931 {
    932 	struct mtd	*mtd;
    933 	void		*txp;
    934 	unsigned short	txp_status;
    935 	int		mtd_hw;
    936 	struct ifnet	*ifp = &sc->sc_if;
    937 
    938 	mtd_hw = sc->mtd_hw;
    939 
    940 	if (mtd_hw == sc->mtd_free)
    941 		return;
    942 
    943 	while (mtd_hw != sc->mtd_free) {
    944 		mtd = &sc->mtda[mtd_hw];
    945 
    946 		txp = mtd->mtd_txp;
    947 
    948 		if (SRO(sc->bitmode, txp, TXP_STATUS) == 0) {
    949 			break; /* it hasn't really gone yet */
    950 		}
    951 
    952 #ifdef SNDEBUG
    953 		{
    954 			struct ether_header *eh;
    955 
    956 			eh = (struct ether_header *) mtd->mtd_buf;
    957 			printf("%s: xmit status=0x%x len=%d type=0x%x from %s",
    958 			    sc->sc_dev.dv_xname,
    959 			    SRO(sc->bitmode, txp, TXP_STATUS),
    960 			    SRO(sc->bitmode, txp, TXP_PKTSIZE),
    961 			    htons(eh->ether_type),
    962 			    ether_sprintf(eh->ether_shost));
    963 			printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
    964 		}
    965 #endif /* SNDEBUG */
    966 
    967 		ifp->if_flags &= ~IFF_OACTIVE;
    968 
    969 		if (mtd->mtd_mbuf != 0) {
    970 			m_freem(mtd->mtd_mbuf);
    971 			mtd->mtd_mbuf = 0;
    972 		}
    973 		if (++mtd_hw == NTDA) mtd_hw = 0;
    974 
    975 		txp_status = SRO(sc->bitmode, txp, TXP_STATUS);
    976 
    977 		ifp->if_collisions += (txp_status & TCR_EXC) ? 16 :
    978 			((txp_status & TCR_NC) >> 12);
    979 
    980 		if ((txp_status & TCR_PTX) == 0) {
    981 			ifp->if_oerrors++;
    982 			printf("%s: Tx packet status=0x%x\n",
    983 			    sc->sc_dev.dv_xname, txp_status);
    984 
    985 			/* XXX - DG This looks bogus */
    986 			if (mtd_hw != sc->mtd_free) {
    987 				printf("resubmitting remaining packets\n");
    988 				mtd = &sc->mtda[mtd_hw];
    989 				NIC_PUT(sc, SNR_CTDA, LOWER(mtd->mtd_vtxp));
    990 				NIC_PUT(sc, SNR_CR, CR_TXP);
    991 				wbflush();
    992 				break;
    993 			}
    994 		}
    995 	}
    996 
    997 	sc->mtd_hw = mtd_hw;
    998 	return;
    999 }
   1000 
   1001 /*
   1002  * Receive interrupt routine
   1003  */
   1004 static void
   1005 sonicrxint(sc)
   1006 	struct sn_softc *sc;
   1007 {
   1008 	caddr_t	rda;
   1009 	int	orra;
   1010 	int	len;
   1011 	int	rramark;
   1012 	int	rdamark;
   1013 	int	bitmode = sc->bitmode;
   1014 	u_int16_t rxpkt_ptr;
   1015 
   1016 	rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1017 
   1018 	while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
   1019 		u_int status = SRO(bitmode, rda, RXPKT_STATUS);
   1020 
   1021 		orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
   1022 		rxpkt_ptr = SRO(bitmode, rda, RXPKT_PTRLO);
   1023 		len = SRO(bitmode, rda, RXPKT_BYTEC) - FCSSIZE;
   1024 		if (status & RCR_PRX) {
   1025 			caddr_t pkt = sc->rbuf[orra & RBAMASK] +
   1026 			    m68k_page_offset(rxpkt_ptr);
   1027 			if (sonic_read(sc, pkt, len))
   1028 				sc->sc_if.if_ipackets++;
   1029 			else
   1030 				sc->sc_if.if_ierrors++;
   1031 		} else
   1032 			sc->sc_if.if_ierrors++;
   1033 
   1034 		/*
   1035 		 * give receive buffer area back to chip.
   1036 		 *
   1037 		 * If this was the last packet in the RRA, give the RRA to
   1038 		 * the chip again.
   1039 		 * If sonic read didnt copy it out then we would have to
   1040 		 * wait !!
   1041 		 * (dont bother add it back in again straight away)
   1042 		 *
   1043 		 * Really, we're doing p_rra[rramark] = p_rra[orra] but
   1044 		 * we have to use the macros because SONIC might be in
   1045 		 * 16 or 32 bit mode.
   1046 		 */
   1047 		if (status & RCR_LPKT) {
   1048 			void *tmp1, *tmp2;
   1049 
   1050 			rramark = sc->sc_rramark;
   1051 			tmp1 = sc->p_rra[rramark];
   1052 			tmp2 = sc->p_rra[orra];
   1053 			SWO(bitmode, tmp1, RXRSRC_PTRLO,
   1054 				SRO(bitmode, tmp2, RXRSRC_PTRLO));
   1055 			SWO(bitmode, tmp1, RXRSRC_PTRHI,
   1056 				SRO(bitmode, tmp2, RXRSRC_PTRHI));
   1057 			SWO(bitmode, tmp1, RXRSRC_WCLO,
   1058 				SRO(bitmode, tmp2, RXRSRC_WCLO));
   1059 			SWO(bitmode, tmp1, RXRSRC_WCHI,
   1060 				SRO(bitmode, tmp2, RXRSRC_WCHI));
   1061 
   1062 			/* zap old rra for fun */
   1063 			SWO(bitmode, tmp2, RXRSRC_WCHI, 0);
   1064 			SWO(bitmode, tmp2, RXRSRC_WCLO, 0);
   1065 
   1066 			sc->sc_rramark = (++rramark) & RRAMASK;
   1067 			NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[rramark]));
   1068 			wbflush();
   1069 		}
   1070 
   1071 		/*
   1072 		 * give receive descriptor back to chip simple
   1073 		 * list is circular
   1074 		 */
   1075 		rdamark = sc->sc_rdamark;
   1076 		SWO(bitmode, rda, RXPKT_INUSE, 1);
   1077 		SWO(bitmode, rda, RXPKT_RLINK,
   1078 			SRO(bitmode, rda, RXPKT_RLINK) | EOL);
   1079 		SWO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))), RXPKT_RLINK,
   1080 			SRO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))),
   1081 			RXPKT_RLINK) & ~EOL);
   1082 		sc->sc_rdamark = sc->sc_rxmark;
   1083 
   1084 		if (++sc->sc_rxmark >= sc->sc_nrda)
   1085 			sc->sc_rxmark = 0;
   1086 		rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1087 	}
   1088 }
   1089 
   1090 /*
   1091  * sonic_read -- pull packet off interface and forward to
   1092  * appropriate protocol handler
   1093  */
   1094 static __inline__ int
   1095 sonic_read(sc, pkt, len)
   1096 	struct sn_softc *sc;
   1097 	caddr_t pkt;
   1098 	int len;
   1099 {
   1100 	struct ifnet *ifp = &sc->sc_if;
   1101 	struct mbuf *m;
   1102 
   1103 #ifdef SNDEBUG
   1104 	{
   1105 		printf("%s: rcvd 0x%p len=%d type=0x%x from %s",
   1106 		    sc->sc_dev.dv_xname, et, len, htons(et->ether_type),
   1107 		    ether_sprintf(et->ether_shost));
   1108 		printf(" (to %s)\n", ether_sprintf(et->ether_dhost));
   1109 	}
   1110 #endif /* SNDEBUG */
   1111 
   1112 	if (len < (ETHER_MIN_LEN - ETHER_CRC_LEN) ||
   1113 	    len > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
   1114 		printf("%s: invalid packet length %d bytes\n",
   1115 		    sc->sc_dev.dv_xname, len);
   1116 		return (0);
   1117 	}
   1118 
   1119 	m = sonic_get(sc, pkt, len);
   1120 	if (m == NULL)
   1121 		return (0);
   1122 #if NBPFILTER > 0
   1123 	/* Pass this up to any BPF listeners. */
   1124 	if (ifp->if_bpf)
   1125 		bpf_mtap(ifp->if_bpf, m);
   1126 #endif
   1127 	(*ifp->if_input)(ifp, m);
   1128 	return (1);
   1129 }
   1130 
   1131 /*
   1132  * munge the received packet into an mbuf chain
   1133  */
   1134 static __inline__ struct mbuf *
   1135 sonic_get(sc, pkt, datalen)
   1136 	struct sn_softc *sc;
   1137 	caddr_t pkt;
   1138 	int datalen;
   1139 {
   1140 	struct	mbuf *m, *top, **mp;
   1141 	int	len;
   1142 
   1143 	MGETHDR(m, M_DONTWAIT, MT_DATA);
   1144 	if (m == 0)
   1145 		return (0);
   1146 	m->m_pkthdr.rcvif = &sc->sc_if;
   1147 	m->m_pkthdr.len = datalen;
   1148 	len = MHLEN;
   1149 	top = 0;
   1150 	mp = &top;
   1151 
   1152 	while (datalen > 0) {
   1153 		if (top) {
   1154 			MGET(m, M_DONTWAIT, MT_DATA);
   1155 			if (m == 0) {
   1156 				m_freem(top);
   1157 				return (0);
   1158 			}
   1159 			len = MLEN;
   1160 		}
   1161 		if (datalen >= MINCLSIZE) {
   1162 			MCLGET(m, M_DONTWAIT);
   1163 			if ((m->m_flags & M_EXT) == 0) {
   1164 				if (top) m_freem(top);
   1165 				return (0);
   1166 			}
   1167 			len = MCLBYTES;
   1168 		}
   1169 
   1170 		if (mp == &top) {
   1171 			caddr_t newdata = (caddr_t)
   1172 			    ALIGN(m->m_data + sizeof(struct ether_header)) -
   1173 			    sizeof(struct ether_header);
   1174 			len -= newdata - m->m_data;
   1175 			m->m_data = newdata;
   1176 		}
   1177 
   1178 		m->m_len = len = min(datalen, len);
   1179 
   1180 		bcopy(pkt, mtod(m, caddr_t), (unsigned) len);
   1181 		pkt += len;
   1182 		datalen -= len;
   1183 		*mp = m;
   1184 		mp = &m->m_next;
   1185 	}
   1186 
   1187 	return (top);
   1188 }
   1189 
   1190 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
   1191 #define bbr(v)	((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
   1192 
   1193 void
   1194 sn_get_enaddr(t, h, o, dst)
   1195 	bus_space_tag_t	t;
   1196 	bus_space_handle_t h;
   1197 	bus_size_t o;
   1198 	u_char *dst;
   1199 {
   1200 	int	i, do_bbr;
   1201 	u_char	b;
   1202 
   1203 	/*
   1204 	 * For reasons known only to Apple, MAC addresses in the ethernet
   1205 	 * PROM are stored in Token Ring (IEEE 802.5) format, that is
   1206 	 * with all of the bits in each byte reversed (canonical bit format).
   1207 	 * When the address is read out it must be reversed to ethernet format
   1208 	 * before use.
   1209 	 *
   1210 	 * Apple has been assigned OUI's 08:00:07 and 00:a0:40. All onboard
   1211 	 * ethernet addresses on 68K machines should be in one of these
   1212 	 * two ranges.
   1213 	 *
   1214 	 * Here is where it gets complicated.
   1215 	 *
   1216 	 * The PMac 7200, 7500, 8500, and 9500 accidentally had the PROM
   1217 	 * written in standard ethernet format. The MacOS accounted for this
   1218 	 * in these systems, and did not reverse the bytes. Some other
   1219 	 * networking utilities were not so forgiving, and got confused.
   1220 	 * "Some" of Apple's Nubus ethernet cards also had their bits
   1221 	 * burned in ethernet format.
   1222 	 *
   1223 	 * Apple petitioned the IEEE and was granted the 00:05:02 (bit reversal
   1224 	 * of 00:a0:40) as well. As of OpenTransport 1.1.1, Apple removed
   1225 	 * their workaround and now reverses the bits regardless of
   1226 	 * what kind of machine it is. So PMac systems and the affected
   1227 	 * Nubus cards now use 00:05:02, instead of the 00:a0:40 for which they
   1228 	 * were intended.
   1229 	 *
   1230 	 * See Apple Techinfo article TECHINFO-0020552, "OpenTransport 1.1.1
   1231 	 * and MacOS System 7.5.3 FAQ (10/96)" for more details.
   1232 	 */
   1233 	do_bbr = 0;
   1234 	b = bus_space_read_1(t, h, o);
   1235 	if (b == 0x10)
   1236 		do_bbr = 1;
   1237 	dst[0] = (do_bbr) ? bbr(b) : b;
   1238 
   1239 	for (i = 1 ; i < ETHER_ADDR_LEN ; i++) {
   1240 		b = bus_space_read_1(t, h, o+i);
   1241 		dst[i] = (do_bbr) ? bbr(b) : b;
   1242 	}
   1243 }
   1244