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if_sn.c revision 1.30
      1 /*	$NetBSD: if_sn.c,v 1.30 2001/07/22 13:34:05 wiz 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 <net/if.h>
     32 #include <net/if_dl.h>
     33 #include <net/if_ether.h>
     34 
     35 #ifdef INET
     36 #include <netinet/in.h>
     37 #include <netinet/in_systm.h>
     38 #include <netinet/in_var.h>
     39 #include <netinet/ip.h>
     40 #include <netinet/if_inarp.h>
     41 #endif
     42 
     43 #include <uvm/uvm_extern.h>
     44 
     45 #include "bpfilter.h"
     46 #if NBPFILTER > 0
     47 #include <net/bpf.h>
     48 #include <net/bpfdesc.h>
     49 #endif
     50 
     51 #include <machine/bus.h>
     52 #include <machine/cpu.h>
     53 #include <machine/viareg.h>
     54 #include <mac68k/dev/if_snreg.h>
     55 #include <mac68k/dev/if_snvar.h>
     56 
     57 static void	snwatchdog __P((struct ifnet *));
     58 static int	sninit __P((struct sn_softc *sc));
     59 static int	snstop __P((struct sn_softc *sc));
     60 static int	snioctl __P((struct ifnet *ifp, u_long cmd, caddr_t data));
     61 static void	snstart __P((struct ifnet *ifp));
     62 static void	snreset __P((struct sn_softc *sc));
     63 
     64 static void	caminitialise __P((struct sn_softc *));
     65 static void	camentry __P((struct sn_softc *, int, u_char *ea));
     66 static void	camprogram __P((struct sn_softc *));
     67 static void	initialise_tda __P((struct sn_softc *));
     68 static void	initialise_rda __P((struct sn_softc *));
     69 static void	initialise_rra __P((struct sn_softc *));
     70 #ifdef SNDEBUG
     71 static void	camdump __P((struct sn_softc *sc));
     72 #endif
     73 
     74 static void	sonictxint __P((struct sn_softc *));
     75 static void	sonicrxint __P((struct sn_softc *));
     76 
     77 static __inline__ u_int	sonicput __P((struct sn_softc *sc, struct mbuf *m0,
     78 			    int mtd_next));
     79 static __inline__ int	sonic_read __P((struct sn_softc *, caddr_t, int));
     80 static __inline__ struct mbuf *sonic_get __P((struct sn_softc *, caddr_t, int));
     81 
     82 #undef assert
     83 #undef _assert
     84 
     85 #ifdef NDEBUG
     86 #define	assert(e)	((void)0)
     87 #define	_assert(e)	((void)0)
     88 #else
     89 #define	_assert(e)	assert(e)
     90 #ifdef __STDC__
     91 #define	assert(e)	((e) ? (void)0 : __assert("sn ", __FILE__, __LINE__, #e))
     92 #else	/* PCC */
     93 #define	assert(e)	((e) ? (void)0 : __assert("sn "__FILE__, __LINE__, "e"))
     94 #endif
     95 #endif
     96 
     97 int sndebug = 0;
     98 
     99 /*
    100  * SONIC buffers need to be aligned 16 or 32 bit aligned.
    101  * These macros calculate and verify alignment.
    102  */
    103 #define	ROUNDUP(p, N)	(((int) p + N - 1) & ~(N - 1))
    104 
    105 #define SOALIGN(m, array)	(m ? (ROUNDUP(array, 4)) : (ROUNDUP(array, 2)))
    106 
    107 #define LOWER(x) ((unsigned)(x) & 0xffff)
    108 #define UPPER(x) ((unsigned)(x) >> 16)
    109 
    110 /*
    111  * Interface exists: make available by filling in network interface
    112  * record.  System will initialize the interface when it is ready
    113  * to accept packets.
    114  */
    115 int
    116 snsetup(sc, lladdr)
    117 	struct sn_softc	*sc;
    118 	u_int8_t *lladdr;
    119 {
    120 	struct ifnet *ifp = &sc->sc_if;
    121 	u_char	*p;
    122 	u_char	*pp;
    123 	int	i;
    124 	int	offset;
    125 
    126 	/*
    127 	 * XXX if_sn.c is intended to be MI. Should it allocate memory
    128 	 * for its descriptor areas, or expect the MD attach code
    129 	 * to do that?
    130 	 */
    131 	sc->space = malloc((SN_NPAGES + 1) * NBPG, M_DEVBUF, M_WAITOK);
    132 	if (sc->space == NULL) {
    133 		printf ("%s: memory allocation for descriptors failed\n",
    134 		    sc->sc_dev.dv_xname);
    135 		return (1);
    136 	}
    137 
    138 	/*
    139 	 * Put the pup in reset mode (sninit() will fix it later),
    140 	 * stop the timer, disable all interrupts and clear any interrupts.
    141 	 */
    142 	NIC_PUT(sc, SNR_CR, CR_STP);
    143 	wbflush();
    144 	NIC_PUT(sc, SNR_CR, CR_RST);
    145 	wbflush();
    146 	NIC_PUT(sc, SNR_IMR, 0);
    147 	wbflush();
    148 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    149 	wbflush();
    150 
    151 	/*
    152 	 * because the SONIC is basically 16bit device it 'concatenates'
    153 	 * a higher buffer address to a 16 bit offset--this will cause wrap
    154 	 * around problems near the end of 64k !!
    155 	 */
    156 	p = sc->space;
    157 	pp = (u_char *)ROUNDUP ((int)p, NBPG);
    158 	p = pp;
    159 
    160 	/*
    161 	 * Disable caching on the SONIC's data space.
    162 	 * The pages might not be physically contiguous, so set
    163 	 * each page individually.
    164 	 */
    165 	for (i = 0; i < SN_NPAGES; i++) {
    166 		physaccess (p, (caddr_t)SONIC_GETDMA(p), NBPG,
    167 		    PG_V | PG_RW | PG_CI);
    168 		p += NBPG;
    169 	}
    170 	p = pp;
    171 
    172 	for (i = 0; i < NRRA; i++) {
    173 		sc->p_rra[i] = (void *)p;
    174 		sc->v_rra[i] = SONIC_GETDMA(p);
    175 		p += RXRSRC_SIZE(sc);
    176 	}
    177 	sc->v_rea = SONIC_GETDMA(p);
    178 
    179 	p = (u_char *)SOALIGN(sc, p);
    180 
    181 	sc->p_cda = (void *)(p);
    182 	sc->v_cda = SONIC_GETDMA(p);
    183 	p += CDA_SIZE(sc);
    184 
    185 	p = (u_char *)SOALIGN(sc, p);
    186 
    187 	for (i = 0; i < NTDA; i++) {
    188 		struct mtd *mtdp = &sc->mtda[i];
    189 		mtdp->mtd_txp = (void *)p;
    190 		mtdp->mtd_vtxp = SONIC_GETDMA(p);
    191 		p += TXP_SIZE(sc);
    192 	}
    193 
    194 	p = (u_char *)SOALIGN(sc, p);
    195 
    196 	if ((p - pp) > NBPG) {
    197 		printf ("%s: sizeof RRA (%ld) + CDA (%ld) +"
    198 		    "TDA (%ld) > NBPG (%d). Punt!\n",
    199 		    sc->sc_dev.dv_xname,
    200 		    (ulong)sc->p_cda - (ulong)sc->p_rra[0],
    201 		    (ulong)sc->mtda[0].mtd_txp - (ulong)sc->p_cda,
    202 		    (ulong)p - (ulong)sc->mtda[0].mtd_txp,
    203 		    NBPG);
    204 		return(1);
    205 	}
    206 
    207 	p = pp + NBPG;
    208 	pp = p;
    209 
    210 	sc->sc_nrda = NBPG / RXPKT_SIZE(sc);
    211 	sc->p_rda = (caddr_t) p;
    212 	sc->v_rda = SONIC_GETDMA(p);
    213 
    214 	p = pp + NBPG;
    215 
    216 	for (i = 0; i < NRBA; i++) {
    217 		sc->rbuf[i] = (caddr_t)p;
    218 		p += NBPG;
    219 	}
    220 
    221 	pp = p;
    222 	offset = TXBSIZE;
    223 	for (i = 0; i < NTDA; i++) {
    224 		struct mtd *mtdp = &sc->mtda[i];
    225 
    226 		mtdp->mtd_buf = p;
    227 		mtdp->mtd_vbuf = SONIC_GETDMA(p);
    228 		offset += TXBSIZE;
    229 		if (offset < NBPG) {
    230 			p += TXBSIZE;
    231 		} else {
    232 			p = pp + NBPG;
    233 			pp = p;
    234 			offset = TXBSIZE;
    235 		}
    236 	}
    237 
    238 #ifdef SNDEBUG
    239 	camdump(sc);
    240 #endif
    241 	printf("%s: Ethernet address %s\n",
    242 	    sc->sc_dev.dv_xname, ether_sprintf(lladdr));
    243 
    244 #ifdef SNDEBUG
    245 	printf("%s: buffers: rra=%p cda=%p rda=%p tda=%p\n",
    246 	    sc->sc_dev.dv_xname, sc->p_rra[0], sc->p_cda,
    247 	    sc->p_rda, sc->mtda[0].mtd_txp);
    248 #endif
    249 
    250 	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
    251 	ifp->if_softc = sc;
    252 	ifp->if_ioctl = snioctl;
    253 	ifp->if_start = snstart;
    254 	ifp->if_flags =
    255 	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
    256 	ifp->if_watchdog = snwatchdog;
    257 
    258 	if_attach(ifp);
    259 	ether_ifattach(ifp, lladdr);
    260 
    261 	return (0);
    262 }
    263 
    264 static int
    265 snioctl(ifp, cmd, data)
    266 	struct ifnet *ifp;
    267 	u_long cmd;
    268 	caddr_t data;
    269 {
    270 	struct ifaddr *ifa;
    271 	struct ifreq *ifr;
    272 	struct sn_softc *sc = ifp->if_softc;
    273 	int	s = splnet(), err = 0;
    274 	int	temp;
    275 
    276 	switch (cmd) {
    277 
    278 	case SIOCSIFADDR:
    279 		ifa = (struct ifaddr *)data;
    280 		ifp->if_flags |= IFF_UP;
    281 		switch (ifa->ifa_addr->sa_family) {
    282 #ifdef INET
    283 		case AF_INET:
    284 			(void)sninit(sc);
    285 			arp_ifinit(ifp, ifa);
    286 			break;
    287 #endif
    288 		default:
    289 			(void)sninit(sc);
    290 			break;
    291 		}
    292 		break;
    293 
    294 	case SIOCSIFFLAGS:
    295 		if ((ifp->if_flags & IFF_UP) == 0 &&
    296 		    (ifp->if_flags & IFF_RUNNING) != 0) {
    297 			/*
    298 			 * If interface is marked down and it is running,
    299 			 * then stop it.
    300 			 */
    301 			snstop(sc);
    302 			ifp->if_flags &= ~IFF_RUNNING;
    303 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
    304 		    (ifp->if_flags & IFF_RUNNING) == 0) {
    305 			/*
    306 			 * If interface is marked up and it is stopped,
    307 			 * then start it.
    308 			 */
    309 			(void)sninit(sc);
    310 		} else {
    311 			/*
    312 			 * reset the interface to pick up any other changes
    313 			 * in flags
    314 			 */
    315 			temp = ifp->if_flags & IFF_UP;
    316 			snreset(sc);
    317 			ifp->if_flags |= temp;
    318 			snstart(ifp);
    319 		}
    320 		break;
    321 
    322 	case SIOCADDMULTI:
    323 	case SIOCDELMULTI:
    324 		ifr = (struct ifreq *) data;
    325 		if (cmd == SIOCADDMULTI)
    326 			err = ether_addmulti(ifr, &sc->sc_ethercom);
    327 		else
    328 			err = ether_delmulti(ifr, &sc->sc_ethercom);
    329 
    330 		if (err == ENETRESET) {
    331 			/*
    332 			 * Multicast list has changed; set the hardware
    333 			 * filter accordingly. But remember UP flag!
    334 			 */
    335 			temp = ifp->if_flags & IFF_UP;
    336 			snreset(sc);
    337 			ifp->if_flags |= temp;
    338 			err = 0;
    339 		}
    340 		break;
    341 	default:
    342 		err = EINVAL;
    343 	}
    344 	splx(s);
    345 	return (err);
    346 }
    347 
    348 /*
    349  * Encapsulate a packet of type family for the local net.
    350  */
    351 static void
    352 snstart(ifp)
    353 	struct ifnet *ifp;
    354 {
    355 	struct sn_softc	*sc = ifp->if_softc;
    356 	struct mbuf	*m;
    357 	int		mtd_next;
    358 
    359 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
    360 		return;
    361 
    362 outloop:
    363 	/* Check for room in the xmit buffer. */
    364 	if ((mtd_next = (sc->mtd_free + 1)) == NTDA)
    365 		mtd_next = 0;
    366 
    367 	if (mtd_next == sc->mtd_hw) {
    368 		ifp->if_flags |= IFF_OACTIVE;
    369 		return;
    370 	}
    371 
    372 	IF_DEQUEUE(&ifp->if_snd, m);
    373 	if (m == 0)
    374 		return;
    375 
    376 	/* We need the header for m_pkthdr.len. */
    377 	if ((m->m_flags & M_PKTHDR) == 0)
    378 		panic("%s: snstart: no header mbuf", sc->sc_dev.dv_xname);
    379 
    380 #if NBPFILTER > 0
    381 	/*
    382 	 * If bpf is listening on this interface, let it
    383 	 * see the packet before we commit it to the wire.
    384 	 */
    385 	if (ifp->if_bpf)
    386 		bpf_mtap(ifp->if_bpf, m);
    387 #endif
    388 
    389 	/*
    390 	 * If there is nothing in the o/p queue, and there is room in
    391 	 * the Tx ring, then send the packet directly.  Otherwise append
    392 	 * it to the o/p queue.
    393 	 */
    394 	if ((sonicput(sc, m, mtd_next)) == 0) {
    395 		IF_PREPEND(&ifp->if_snd, m);
    396 		return;
    397 	}
    398 
    399 	sc->mtd_prev = sc->mtd_free;
    400 	sc->mtd_free = mtd_next;
    401 
    402 	ifp->if_opackets++;		/* # of pkts */
    403 
    404 	/* Jump back for possibly more punishment. */
    405 	goto outloop;
    406 }
    407 
    408 /*
    409  * reset and restart the SONIC.  Called in case of fatal
    410  * hardware/software errors.
    411  */
    412 static void
    413 snreset(sc)
    414 	struct sn_softc *sc;
    415 {
    416 	snstop(sc);
    417 	sninit(sc);
    418 }
    419 
    420 static int
    421 sninit(sc)
    422 	struct sn_softc *sc;
    423 {
    424 	u_long	s_rcr;
    425 	int	s;
    426 
    427 	if (sc->sc_if.if_flags & IFF_RUNNING)
    428 		/* already running */
    429 		return (0);
    430 
    431 	s = splnet();
    432 
    433 	NIC_PUT(sc, SNR_CR, CR_RST);	/* DCR only accessible in reset mode! */
    434 
    435 	/* config it */
    436 	NIC_PUT(sc, SNR_DCR, (sc->snr_dcr |
    437 		(sc->bitmode ? DCR_DW32 : DCR_DW16)));
    438 	NIC_PUT(sc, SNR_DCR2, sc->snr_dcr2);
    439 
    440 	s_rcr = RCR_BRD | RCR_LBNONE;
    441 	if (sc->sc_if.if_flags & IFF_PROMISC)
    442 		s_rcr |= RCR_PRO;
    443 	if (sc->sc_if.if_flags & IFF_ALLMULTI)
    444 		s_rcr |= RCR_AMC;
    445 	NIC_PUT(sc, SNR_RCR, s_rcr);
    446 
    447 	NIC_PUT(sc, SNR_IMR, (IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN));
    448 
    449 	/* clear pending interrupts */
    450 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    451 
    452 	/* clear tally counters */
    453 	NIC_PUT(sc, SNR_CRCT, -1);
    454 	NIC_PUT(sc, SNR_FAET, -1);
    455 	NIC_PUT(sc, SNR_MPT, -1);
    456 
    457 	initialise_tda(sc);
    458 	initialise_rda(sc);
    459 	initialise_rra(sc);
    460 
    461 	/* enable the chip */
    462 	NIC_PUT(sc, SNR_CR, 0);
    463 	wbflush();
    464 
    465 	/* program the CAM */
    466 	camprogram(sc);
    467 
    468 	/* get it to read resource descriptors */
    469 	NIC_PUT(sc, SNR_CR, CR_RRRA);
    470 	wbflush();
    471 	while ((NIC_GET(sc, SNR_CR)) & CR_RRRA)
    472 		continue;
    473 
    474 	/* enable rx */
    475 	NIC_PUT(sc, SNR_CR, CR_RXEN);
    476 	wbflush();
    477 
    478 	/* flag interface as "running" */
    479 	sc->sc_if.if_flags |= IFF_RUNNING;
    480 	sc->sc_if.if_flags &= ~IFF_OACTIVE;
    481 
    482 	splx(s);
    483 	return (0);
    484 }
    485 
    486 /*
    487  * close down an interface and free its buffers
    488  * Called on final close of device, or if sninit() fails
    489  * part way through.
    490  */
    491 static int
    492 snstop(sc)
    493 	struct sn_softc *sc;
    494 {
    495 	struct mtd *mtd;
    496 	int	s = splnet();
    497 
    498 	/* stick chip in reset */
    499 	NIC_PUT(sc, SNR_CR, CR_RST);
    500 	wbflush();
    501 
    502 	/* free all receive buffers (currently static so nothing to do) */
    503 
    504 	/* free all pending transmit mbufs */
    505 	while (sc->mtd_hw != sc->mtd_free) {
    506 		mtd = &sc->mtda[sc->mtd_hw];
    507 		if (mtd->mtd_mbuf)
    508 			m_freem(mtd->mtd_mbuf);
    509 		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
    510 	}
    511 
    512 	sc->sc_if.if_timer = 0;
    513 	sc->sc_if.if_flags &= ~(IFF_RUNNING | IFF_UP);
    514 
    515 	splx(s);
    516 	return (0);
    517 }
    518 
    519 /*
    520  * Called if any Tx packets remain unsent after 5 seconds,
    521  * In all cases we just reset the chip, and any retransmission
    522  * will be handled by higher level protocol timeouts.
    523  */
    524 static void
    525 snwatchdog(ifp)
    526 	struct ifnet *ifp;
    527 {
    528 	struct sn_softc *sc = ifp->if_softc;
    529 	struct mtd *mtd;
    530 	int	temp;
    531 
    532 	if (sc->mtd_hw != sc->mtd_free) {
    533 		/* something still pending for transmit */
    534 		mtd = &sc->mtda[sc->mtd_hw];
    535 		if (SRO(sc->bitmode, mtd->mtd_txp, TXP_STATUS) == 0)
    536 			log(LOG_ERR, "%s: Tx - timeout\n",
    537 			    sc->sc_dev.dv_xname);
    538 		else
    539 			log(LOG_ERR, "%s: Tx - lost interrupt\n",
    540 			    sc->sc_dev.dv_xname);
    541 		temp = ifp->if_flags & IFF_UP;
    542 		snreset(sc);
    543 		ifp->if_flags |= temp;
    544 	}
    545 }
    546 
    547 /*
    548  * stuff packet into sonic (at splnet)
    549  */
    550 static __inline__ u_int
    551 sonicput(sc, m0, mtd_next)
    552 	struct sn_softc *sc;
    553 	struct mbuf *m0;
    554 	int mtd_next;
    555 {
    556 	struct mtd *mtdp;
    557 	struct mbuf *m;
    558 	u_char	*buff;
    559 	void	*txp;
    560 	u_int	len = 0;
    561 	u_int	totlen = 0;
    562 
    563 #ifdef whyonearthwouldyoudothis
    564 	if (NIC_GET(sc, SNR_CR) & CR_TXP)
    565 		return (0);
    566 #endif
    567 
    568 	/* grab the replacement mtd */
    569 	mtdp = &sc->mtda[sc->mtd_free];
    570 
    571 	buff = mtdp->mtd_buf;
    572 
    573 	/* this packet goes to mtdnext fill in the TDA */
    574 	mtdp->mtd_mbuf = m0;
    575 	txp = mtdp->mtd_txp;
    576 
    577 	/* Write to the config word. Every (NTDA/2)+1 packets we set an intr */
    578 	if (sc->mtd_pint == 0) {
    579 		sc->mtd_pint = NTDA/2;
    580 		SWO(sc->bitmode, txp, TXP_CONFIG, TCR_PINT);
    581 	} else {
    582 		sc->mtd_pint--;
    583 		SWO(sc->bitmode, txp, TXP_CONFIG, 0);
    584 	}
    585 
    586 	for (m = m0; m; m = m->m_next) {
    587 		u_char *data = mtod(m, u_char *);
    588 		len = m->m_len;
    589 		totlen += len;
    590 		bcopy(data, buff, len);
    591 		buff += len;
    592 	}
    593 	if (totlen >= TXBSIZE) {
    594 		panic("%s: sonicput: packet overflow", sc->sc_dev.dv_xname);
    595 	}
    596 
    597 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRLO,
    598 	    LOWER(mtdp->mtd_vbuf));
    599 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRHI,
    600 	    UPPER(mtdp->mtd_vbuf));
    601 
    602 	if (totlen < ETHERMIN + ETHER_HDR_LEN) {
    603 		int pad = ETHERMIN + ETHER_HDR_LEN - totlen;
    604 		bzero(mtdp->mtd_buf + totlen, pad);
    605 		totlen = ETHERMIN + ETHER_HDR_LEN;
    606 	}
    607 
    608 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FSIZE,
    609 	    totlen);
    610 	SWO(sc->bitmode, txp, TXP_FRAGCNT, 1);
    611 	SWO(sc->bitmode, txp, TXP_PKTSIZE, totlen);
    612 
    613 	/* link onto the next mtd that will be used */
    614 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (1 * TXP_FRAGSIZE) + TXP_FPTRLO,
    615 	    LOWER(sc->mtda[mtd_next].mtd_vtxp) | EOL);
    616 
    617 	/*
    618 	 * The previous txp.tlink currently contains a pointer to
    619 	 * our txp | EOL. Want to clear the EOL, so write our
    620 	 * pointer to the previous txp.
    621 	 */
    622 	SWO(sc->bitmode, sc->mtda[sc->mtd_prev].mtd_txp, sc->mtd_tlinko,
    623 	    LOWER(mtdp->mtd_vtxp));
    624 
    625 	/* make sure chip is running */
    626 	wbflush();
    627 	NIC_PUT(sc, SNR_CR, CR_TXP);
    628 	wbflush();
    629 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
    630 
    631 	return (totlen);
    632 }
    633 
    634 /*
    635  * These are called from sonicioctl() when /etc/ifconfig is run to set
    636  * the address or switch the i/f on.
    637  */
    638 /*
    639  * CAM support
    640  */
    641 static void
    642 caminitialise(sc)
    643 	struct sn_softc *sc;
    644 {
    645 	void	*p_cda = sc->p_cda;
    646 	int	i;
    647 	int	bitmode = sc->bitmode;
    648 	int	camoffset;
    649 
    650 	for (i = 0; i < MAXCAM; i++) {
    651 		camoffset = i * CDA_CAMDESC;
    652 		SWO(bitmode, p_cda, (camoffset + CDA_CAMEP), i);
    653 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP2), 0);
    654 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP1), 0);
    655 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP0), 0);
    656 	}
    657 	SWO(bitmode, p_cda, CDA_ENABLE, 0);
    658 }
    659 
    660 static void
    661 camentry(sc, entry, ea)
    662 	int entry;
    663 	u_char *ea;
    664 	struct sn_softc *sc;
    665 {
    666 	void	*p_cda = sc->p_cda;
    667 	int	bitmode = sc->bitmode;
    668 	int	camoffset = entry * CDA_CAMDESC;
    669 
    670 	SWO(bitmode, p_cda, camoffset + CDA_CAMEP, entry);
    671 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP2, (ea[5] << 8) | ea[4]);
    672 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP1, (ea[3] << 8) | ea[2]);
    673 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP0, (ea[1] << 8) | ea[0]);
    674 	SWO(bitmode, p_cda, CDA_ENABLE,
    675 	    (SRO(bitmode, p_cda, CDA_ENABLE) | (1 << entry)));
    676 }
    677 
    678 static void
    679 camprogram(sc)
    680 	struct sn_softc *sc;
    681 {
    682 	struct ether_multistep step;
    683 	struct ether_multi *enm;
    684 	struct ifnet *ifp;
    685 	int	timeout;
    686 	int	mcount = 0;
    687 
    688 	caminitialise(sc);
    689 
    690 	ifp = &sc->sc_if;
    691 
    692 	/* Always load our own address first. */
    693 	camentry (sc, mcount, LLADDR(ifp->if_sadl));
    694 	mcount++;
    695 
    696 	/* Assume we won't need allmulti bit. */
    697 	ifp->if_flags &= ~IFF_ALLMULTI;
    698 
    699 	/* Loop through multicast addresses */
    700 	ETHER_FIRST_MULTI(step, &sc->sc_ethercom, enm);
    701 	while (enm != NULL) {
    702 		if (mcount == MAXCAM) {
    703 			 ifp->if_flags |= IFF_ALLMULTI;
    704 			 break;
    705 		}
    706 
    707 		if (bcmp(enm->enm_addrlo, enm->enm_addrhi,
    708 		    sizeof(enm->enm_addrlo)) != 0) {
    709 			/*
    710 			 * SONIC's CAM is programmed with specific
    711 			 * addresses. It has no way to specify a range.
    712 			 * (Well, thats not exactly true. If the
    713 			 * range is small one could program each addr
    714 			 * within the range as a separate CAM entry)
    715 			 */
    716 			ifp->if_flags |= IFF_ALLMULTI;
    717 			break;
    718 		}
    719 
    720 		/* program the CAM with the specified entry */
    721 		camentry(sc, mcount, enm->enm_addrlo);
    722 		mcount++;
    723 
    724 		ETHER_NEXT_MULTI(step, enm);
    725 	}
    726 
    727 	NIC_PUT(sc, SNR_CDP, LOWER(sc->v_cda));
    728 	NIC_PUT(sc, SNR_CDC, MAXCAM);
    729 	NIC_PUT(sc, SNR_CR, CR_LCAM);
    730 	wbflush();
    731 
    732 	timeout = 10000;
    733 	while ((NIC_GET(sc, SNR_CR) & CR_LCAM) && timeout--)
    734 		continue;
    735 	if (timeout == 0) {
    736 		/* XXX */
    737 		panic("%s: CAM initialisation failed\n", sc->sc_dev.dv_xname);
    738 	}
    739 	timeout = 10000;
    740 	while (((NIC_GET(sc, SNR_ISR) & ISR_LCD) == 0) && timeout--)
    741 		continue;
    742 
    743 	if (NIC_GET(sc, SNR_ISR) & ISR_LCD)
    744 		NIC_PUT(sc, SNR_ISR, ISR_LCD);
    745 	else
    746 		printf("%s: CAM initialisation without interrupt\n",
    747 		    sc->sc_dev.dv_xname);
    748 }
    749 
    750 #ifdef SNDEBUG
    751 static void
    752 camdump(sc)
    753 	struct sn_softc *sc;
    754 {
    755 	int	i;
    756 
    757 	printf("CAM entries:\n");
    758 	NIC_PUT(sc, SNR_CR, CR_RST);
    759 	wbflush();
    760 
    761 	for (i = 0; i < 16; i++) {
    762 		ushort  ap2, ap1, ap0;
    763 		NIC_PUT(sc, SNR_CEP, i);
    764 		wbflush();
    765 		ap2 = NIC_GET(sc, SNR_CAP2);
    766 		ap1 = NIC_GET(sc, SNR_CAP1);
    767 		ap0 = NIC_GET(sc, SNR_CAP0);
    768 		printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
    769 	}
    770 	printf("CAM enable 0x%x\n", NIC_GET(sc, SNR_CEP));
    771 
    772 	NIC_PUT(sc, SNR_CR, 0);
    773 	wbflush();
    774 }
    775 #endif
    776 
    777 static void
    778 initialise_tda(sc)
    779 	struct sn_softc *sc;
    780 {
    781 	struct mtd *mtd;
    782 	int	i;
    783 
    784 	for (i = 0; i < NTDA; i++) {
    785 		mtd = &sc->mtda[i];
    786 		mtd->mtd_mbuf = 0;
    787 	}
    788 
    789 	sc->mtd_hw = 0;
    790 	sc->mtd_prev = NTDA - 1;
    791 	sc->mtd_free = 0;
    792 	sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;
    793 	sc->mtd_pint = NTDA/2;
    794 
    795 	NIC_PUT(sc, SNR_UTDA, UPPER(sc->mtda[0].mtd_vtxp));
    796 	NIC_PUT(sc, SNR_CTDA, LOWER(sc->mtda[0].mtd_vtxp));
    797 }
    798 
    799 static void
    800 initialise_rda(sc)
    801 	struct sn_softc *sc;
    802 {
    803 	int		bitmode = sc->bitmode;
    804 	int		i;
    805 	caddr_t		p_rda = 0;
    806 	u_int32_t	v_rda = 0;
    807 
    808 	/* link the RDA's together into a circular list */
    809 	for (i = 0; i < (sc->sc_nrda - 1); i++) {
    810 		p_rda = sc->p_rda + (i * RXPKT_SIZE(sc));
    811 		v_rda = sc->v_rda + ((i+1) * RXPKT_SIZE(sc));
    812 		SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(v_rda));
    813 		SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    814 	}
    815 	p_rda = sc->p_rda + ((sc->sc_nrda - 1) * RXPKT_SIZE(sc));
    816 	SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(sc->v_rda) | EOL);
    817 	SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    818 
    819 	/* mark end of receive descriptor list */
    820 	sc->sc_rdamark = sc->sc_nrda - 1;
    821 
    822 	sc->sc_rxmark = 0;
    823 
    824 	NIC_PUT(sc, SNR_URDA, UPPER(sc->v_rda));
    825 	NIC_PUT(sc, SNR_CRDA, LOWER(sc->v_rda));
    826 	wbflush();
    827 }
    828 
    829 static void
    830 initialise_rra(sc)
    831 	struct sn_softc *sc;
    832 {
    833 	int	i;
    834 	u_int	v;
    835 	int	bitmode = sc->bitmode;
    836 
    837 	if (bitmode)
    838 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 2);
    839 	else
    840 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 1);
    841 
    842 	NIC_PUT(sc, SNR_URRA, UPPER(sc->v_rra[0]));
    843 	NIC_PUT(sc, SNR_RSA, LOWER(sc->v_rra[0]));
    844 	/* rea must point just past the end of the rra space */
    845 	NIC_PUT(sc, SNR_REA, LOWER(sc->v_rea));
    846 	NIC_PUT(sc, SNR_RRP, LOWER(sc->v_rra[0]));
    847 	NIC_PUT(sc, SNR_RSC, 0);
    848 
    849 	/* fill up SOME of the rra with buffers */
    850 	for (i = 0; i < NRBA; i++) {
    851 		v = SONIC_GETDMA(sc->rbuf[i]);
    852 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRHI, UPPER(v));
    853 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRLO, LOWER(v));
    854 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCHI, UPPER(NBPG/2));
    855 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCLO, LOWER(NBPG/2));
    856 	}
    857 	sc->sc_rramark = NRBA;
    858 	NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[sc->sc_rramark]));
    859 	wbflush();
    860 }
    861 
    862 void
    863 snintr(arg)
    864 	void	*arg;
    865 {
    866 	struct sn_softc *sc = (struct sn_softc *)arg;
    867 	int	isr;
    868 
    869 	while ((isr = (NIC_GET(sc, SNR_ISR) & ISR_ALL)) != 0) {
    870 		/* scrub the interrupts that we are going to service */
    871 		NIC_PUT(sc, SNR_ISR, isr);
    872 		wbflush();
    873 
    874 		if (isr & (ISR_BR | ISR_LCD | ISR_TC))
    875 			printf("%s: unexpected interrupt status 0x%x\n",
    876 			    sc->sc_dev.dv_xname, isr);
    877 
    878 		if (isr & (ISR_TXDN | ISR_TXER | ISR_PINT))
    879 			sonictxint(sc);
    880 
    881 		if (isr & ISR_PKTRX)
    882 			sonicrxint(sc);
    883 
    884 		if (isr & (ISR_HBL | ISR_RDE | ISR_RBE | ISR_RBAE | ISR_RFO)) {
    885 			if (isr & ISR_HBL)
    886 				/*
    887 				 * The repeater is not providing a heartbeat.
    888 				 * In itself this isn't harmful, lots of the
    889 				 * cheap repeater hubs don't supply a heartbeat.
    890 				 * So ignore the lack of heartbeat. Its only
    891 				 * if we can't detect a carrier that we have a
    892 				 * problem.
    893 				 */
    894 				;
    895 			if (isr & ISR_RDE)
    896 				printf("%s: receive descriptors exhausted\n",
    897 				    sc->sc_dev.dv_xname);
    898 			if (isr & ISR_RBE)
    899 				printf("%s: receive buffers exhausted\n",
    900 				    sc->sc_dev.dv_xname);
    901 			if (isr & ISR_RBAE)
    902 				printf("%s: receive buffer area exhausted\n",
    903 				    sc->sc_dev.dv_xname);
    904 			if (isr & ISR_RFO)
    905 				printf("%s: receive FIFO overrun\n",
    906 				    sc->sc_dev.dv_xname);
    907 		}
    908 		if (isr & (ISR_CRC | ISR_FAE | ISR_MP)) {
    909 #ifdef notdef
    910 			if (isr & ISR_CRC)
    911 				sc->sc_crctally++;
    912 			if (isr & ISR_FAE)
    913 				sc->sc_faetally++;
    914 			if (isr & ISR_MP)
    915 				sc->sc_mptally++;
    916 #endif
    917 		}
    918 		snstart(&sc->sc_if);
    919 	}
    920 	return;
    921 }
    922 
    923 /*
    924  * Transmit interrupt routine
    925  */
    926 static void
    927 sonictxint(sc)
    928 	struct sn_softc *sc;
    929 {
    930 	struct mtd	*mtd;
    931 	void		*txp;
    932 	unsigned short	txp_status;
    933 	int		mtd_hw;
    934 	struct ifnet	*ifp = &sc->sc_if;
    935 
    936 	mtd_hw = sc->mtd_hw;
    937 
    938 	if (mtd_hw == sc->mtd_free)
    939 		return;
    940 
    941 	while (mtd_hw != sc->mtd_free) {
    942 		mtd = &sc->mtda[mtd_hw];
    943 
    944 		txp = mtd->mtd_txp;
    945 
    946 		if (SRO(sc->bitmode, txp, TXP_STATUS) == 0) {
    947 			break; /* it hasn't really gone yet */
    948 		}
    949 
    950 #ifdef SNDEBUG
    951 		{
    952 			struct ether_header *eh;
    953 
    954 			eh = (struct ether_header *) mtd->mtd_buf;
    955 			printf("%s: xmit status=0x%x len=%d type=0x%x from %s",
    956 			    sc->sc_dev.dv_xname,
    957 			    SRO(sc->bitmode, txp, TXP_STATUS),
    958 			    SRO(sc->bitmode, txp, TXP_PKTSIZE),
    959 			    htons(eh->ether_type),
    960 			    ether_sprintf(eh->ether_shost));
    961 			printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
    962 		}
    963 #endif /* SNDEBUG */
    964 
    965 		ifp->if_flags &= ~IFF_OACTIVE;
    966 
    967 		if (mtd->mtd_mbuf != 0) {
    968 			m_freem(mtd->mtd_mbuf);
    969 			mtd->mtd_mbuf = 0;
    970 		}
    971 		if (++mtd_hw == NTDA) mtd_hw = 0;
    972 
    973 		txp_status = SRO(sc->bitmode, txp, TXP_STATUS);
    974 
    975 		ifp->if_collisions += (txp_status & TCR_EXC) ? 16 :
    976 			((txp_status & TCR_NC) >> 12);
    977 
    978 		if ((txp_status & TCR_PTX) == 0) {
    979 			ifp->if_oerrors++;
    980 			printf("%s: Tx packet status=0x%x\n",
    981 			    sc->sc_dev.dv_xname, txp_status);
    982 
    983 			/* XXX - DG This looks bogus */
    984 			if (mtd_hw != sc->mtd_free) {
    985 				printf("resubmitting remaining packets\n");
    986 				mtd = &sc->mtda[mtd_hw];
    987 				NIC_PUT(sc, SNR_CTDA, LOWER(mtd->mtd_vtxp));
    988 				NIC_PUT(sc, SNR_CR, CR_TXP);
    989 				wbflush();
    990 				break;
    991 			}
    992 		}
    993 	}
    994 
    995 	sc->mtd_hw = mtd_hw;
    996 	return;
    997 }
    998 
    999 /*
   1000  * Receive interrupt routine
   1001  */
   1002 static void
   1003 sonicrxint(sc)
   1004 	struct sn_softc *sc;
   1005 {
   1006 	caddr_t	rda;
   1007 	int	orra;
   1008 	int	len;
   1009 	int	rramark;
   1010 	int	rdamark;
   1011 	int	bitmode = sc->bitmode;
   1012 	u_int16_t rxpkt_ptr;
   1013 
   1014 	rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1015 
   1016 	while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
   1017 		u_int status = SRO(bitmode, rda, RXPKT_STATUS);
   1018 
   1019 		orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
   1020 		rxpkt_ptr = SRO(bitmode, rda, RXPKT_PTRLO);
   1021 		len = SRO(bitmode, rda, RXPKT_BYTEC) - FCSSIZE;
   1022 		if (status & RCR_PRX) {
   1023 			caddr_t pkt = sc->rbuf[orra & RBAMASK] +
   1024 			    m68k_page_offset(rxpkt_ptr);
   1025 			if (sonic_read(sc, pkt, len))
   1026 				sc->sc_if.if_ipackets++;
   1027 			else
   1028 				sc->sc_if.if_ierrors++;
   1029 		} else
   1030 			sc->sc_if.if_ierrors++;
   1031 
   1032 		/*
   1033 		 * give receive buffer area back to chip.
   1034 		 *
   1035 		 * If this was the last packet in the RRA, give the RRA to
   1036 		 * the chip again.
   1037 		 * If sonic read didnt copy it out then we would have to
   1038 		 * wait !!
   1039 		 * (dont bother add it back in again straight away)
   1040 		 *
   1041 		 * Really, we're doing p_rra[rramark] = p_rra[orra] but
   1042 		 * we have to use the macros because SONIC might be in
   1043 		 * 16 or 32 bit mode.
   1044 		 */
   1045 		if (status & RCR_LPKT) {
   1046 			void *tmp1, *tmp2;
   1047 
   1048 			rramark = sc->sc_rramark;
   1049 			tmp1 = sc->p_rra[rramark];
   1050 			tmp2 = sc->p_rra[orra];
   1051 			SWO(bitmode, tmp1, RXRSRC_PTRLO,
   1052 				SRO(bitmode, tmp2, RXRSRC_PTRLO));
   1053 			SWO(bitmode, tmp1, RXRSRC_PTRHI,
   1054 				SRO(bitmode, tmp2, RXRSRC_PTRHI));
   1055 			SWO(bitmode, tmp1, RXRSRC_WCLO,
   1056 				SRO(bitmode, tmp2, RXRSRC_WCLO));
   1057 			SWO(bitmode, tmp1, RXRSRC_WCHI,
   1058 				SRO(bitmode, tmp2, RXRSRC_WCHI));
   1059 
   1060 			/* zap old rra for fun */
   1061 			SWO(bitmode, tmp2, RXRSRC_WCHI, 0);
   1062 			SWO(bitmode, tmp2, RXRSRC_WCLO, 0);
   1063 
   1064 			sc->sc_rramark = (++rramark) & RRAMASK;
   1065 			NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[rramark]));
   1066 			wbflush();
   1067 		}
   1068 
   1069 		/*
   1070 		 * give receive descriptor back to chip simple
   1071 		 * list is circular
   1072 		 */
   1073 		rdamark = sc->sc_rdamark;
   1074 		SWO(bitmode, rda, RXPKT_INUSE, 1);
   1075 		SWO(bitmode, rda, RXPKT_RLINK,
   1076 			SRO(bitmode, rda, RXPKT_RLINK) | EOL);
   1077 		SWO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))), RXPKT_RLINK,
   1078 			SRO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))),
   1079 			RXPKT_RLINK) & ~EOL);
   1080 		sc->sc_rdamark = sc->sc_rxmark;
   1081 
   1082 		if (++sc->sc_rxmark >= sc->sc_nrda)
   1083 			sc->sc_rxmark = 0;
   1084 		rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1085 	}
   1086 }
   1087 
   1088 /*
   1089  * sonic_read -- pull packet off interface and forward to
   1090  * appropriate protocol handler
   1091  */
   1092 static __inline__ int
   1093 sonic_read(sc, pkt, len)
   1094 	struct sn_softc *sc;
   1095 	caddr_t pkt;
   1096 	int len;
   1097 {
   1098 	struct ifnet *ifp = &sc->sc_if;
   1099 	struct mbuf *m;
   1100 
   1101 #ifdef SNDEBUG
   1102 	{
   1103 		printf("%s: rcvd 0x%p len=%d type=0x%x from %s",
   1104 		    sc->sc_dev.dv_xname, et, len, htons(et->ether_type),
   1105 		    ether_sprintf(et->ether_shost));
   1106 		printf(" (to %s)\n", ether_sprintf(et->ether_dhost));
   1107 	}
   1108 #endif /* SNDEBUG */
   1109 
   1110 	if (len < (ETHER_MIN_LEN - ETHER_CRC_LEN) ||
   1111 	    len > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
   1112 		printf("%s: invalid packet length %d bytes\n",
   1113 		    sc->sc_dev.dv_xname, len);
   1114 		return (0);
   1115 	}
   1116 
   1117 #if NBPFILTER > 0
   1118 	/*
   1119 	 * Check if there's a bpf filter listening on this interface.
   1120 	 * If so, hand off the raw packet to enet, then discard things
   1121 	 * not destined for us (but be sure to keep broadcast/multicast).
   1122 	 */
   1123 	if (ifp->if_bpf)
   1124 		bpf_tap(ifp->if_bpf, pkt, len);
   1125 #endif
   1126 	m = sonic_get(sc, pkt, len);
   1127 	if (m == NULL)
   1128 		return (0);
   1129 	(*ifp->if_input)(ifp, m);
   1130 	return (1);
   1131 }
   1132 
   1133 /*
   1134  * munge the received packet into an mbuf chain
   1135  */
   1136 static __inline__ struct mbuf *
   1137 sonic_get(sc, pkt, datalen)
   1138 	struct sn_softc *sc;
   1139 	caddr_t pkt;
   1140 	int datalen;
   1141 {
   1142 	struct	mbuf *m, *top, **mp;
   1143 	int	len;
   1144 
   1145 	MGETHDR(m, M_DONTWAIT, MT_DATA);
   1146 	if (m == 0)
   1147 		return (0);
   1148 	m->m_pkthdr.rcvif = &sc->sc_if;
   1149 	m->m_pkthdr.len = datalen;
   1150 	len = MHLEN;
   1151 	top = 0;
   1152 	mp = &top;
   1153 
   1154 	while (datalen > 0) {
   1155 		if (top) {
   1156 			MGET(m, M_DONTWAIT, MT_DATA);
   1157 			if (m == 0) {
   1158 				m_freem(top);
   1159 				return (0);
   1160 			}
   1161 			len = MLEN;
   1162 		}
   1163 		if (datalen >= MINCLSIZE) {
   1164 			MCLGET(m, M_DONTWAIT);
   1165 			if ((m->m_flags & M_EXT) == 0) {
   1166 				if (top) m_freem(top);
   1167 				return (0);
   1168 			}
   1169 			len = MCLBYTES;
   1170 		}
   1171 
   1172 		if (mp == &top) {
   1173 			caddr_t newdata = (caddr_t)
   1174 			    ALIGN(m->m_data + sizeof(struct ether_header)) -
   1175 			    sizeof(struct ether_header);
   1176 			len -= newdata - m->m_data;
   1177 			m->m_data = newdata;
   1178 		}
   1179 
   1180 		m->m_len = len = min(datalen, len);
   1181 
   1182 		bcopy(pkt, mtod(m, caddr_t), (unsigned) len);
   1183 		pkt += len;
   1184 		datalen -= len;
   1185 		*mp = m;
   1186 		mp = &m->m_next;
   1187 	}
   1188 
   1189 	return (top);
   1190 }
   1191 
   1192 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
   1193 #define bbr(v)	((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
   1194 
   1195 void
   1196 sn_get_enaddr(t, h, o, dst)
   1197 	bus_space_tag_t	t;
   1198 	bus_space_handle_t h;
   1199 	bus_size_t o;
   1200 	u_char *dst;
   1201 {
   1202 	int	i, do_bbr;
   1203 	u_char	b;
   1204 
   1205 	/*
   1206 	 * For reasons known only to Apple, MAC addresses in the ethernet
   1207 	 * PROM are stored in Token Ring (IEEE 802.5) format, that is
   1208 	 * with all of the bits in each byte reversed (canonical bit format).
   1209 	 * When the address is read out it must be reversed to ethernet format
   1210 	 * before use.
   1211 	 *
   1212 	 * Apple has been assigned OUI's 08:00:07 and 00:a0:40. All onboard
   1213 	 * ethernet addresses on 68K machines should be in one of these
   1214 	 * two ranges.
   1215 	 *
   1216 	 * Here is where it gets complicated.
   1217 	 *
   1218 	 * The PMac 7200, 7500, 8500, and 9500 accidentally had the PROM
   1219 	 * written in standard ethernet format. The MacOS accounted for this
   1220 	 * in these systems, and did not reverse the bytes. Some other
   1221 	 * networking utilities were not so forgiving, and got confused.
   1222 	 * "Some" of Apple's Nubus ethernet cards also had their bits
   1223 	 * burned in ethernet format.
   1224 	 *
   1225 	 * Apple petitioned the IEEE and was granted the 00:05:02 (bit reversal
   1226 	 * of 00:a0:40) as well. As of OpenTransport 1.1.1, Apple removed
   1227 	 * their workaround and now reverses the bits regardless of
   1228 	 * what kind of machine it is. So PMac systems and the affected
   1229 	 * Nubus cards now use 00:05:02, instead of the 00:a0:40 for which they
   1230 	 * were intended.
   1231 	 *
   1232 	 * See Apple Techinfo article TECHINFO-0020552, "OpenTransport 1.1.1
   1233 	 * and MacOS System 7.5.3 FAQ (10/96)" for more details.
   1234 	 */
   1235 	do_bbr = 0;
   1236 	b = bus_space_read_1(t, h, o);
   1237 	if (b == 0x10)
   1238 		do_bbr = 1;
   1239 	dst[0] = (do_bbr) ? bbr(b) : b;
   1240 
   1241 	for (i = 1 ; i < ETHER_ADDR_LEN ; i++) {
   1242 		b = bus_space_read_1(t, h, o+i);
   1243 		dst[i] = (do_bbr) ? bbr(b) : b;
   1244 	}
   1245 }
   1246