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if_sn.c revision 1.14
      1 /*	$NetBSD: if_sn.c,v 1.14 1997/05/19 17:23:09 scottr Exp $	*/
      2 
      3 /*
      4  * National Semiconductor  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 <sys/param.h>
     19 #include <sys/systm.h>
     20 #include <sys/mbuf.h>
     21 #include <sys/buf.h>
     22 #include <sys/protosw.h>
     23 #include <sys/socket.h>
     24 #include <sys/syslog.h>
     25 #include <sys/ioctl.h>
     26 #include <sys/errno.h>
     27 #include <sys/device.h>
     28 
     29 #include <net/if.h>
     30 #include <net/if_dl.h>
     31 #include <net/if_ether.h>
     32 
     33 #ifdef INET
     34 #include <netinet/in.h>
     35 #include <netinet/in_systm.h>
     36 #include <netinet/in_var.h>
     37 #include <netinet/ip.h>
     38 #include <netinet/if_inarp.h>
     39 #endif
     40 
     41 #include <vm/vm.h>
     42 
     43 extern int kvtop(caddr_t addr);
     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 static void	initialise_tba __P((struct sn_softc *));
     71 #ifdef DEBUG
     72 static void	camdump __P((struct sn_softc *sc));
     73 #endif
     74 
     75 static void	sonictxint __P((struct sn_softc *));
     76 static void	sonicrxint __P((struct sn_softc *));
     77 
     78 static __inline__ int	sonicput __P((struct sn_softc *sc, struct mbuf *m0));
     79 static __inline__ int	sonic_read __P((struct sn_softc *, caddr_t, int));
     80 static __inline__ struct mbuf *sonic_get __P((struct sn_softc *,
     81 			    struct ether_header *, int));
     82 
     83 struct cfdriver sn_cd = {
     84 	NULL, "sn", DV_IFNET
     85 };
     86 
     87 #undef assert
     88 #undef _assert
     89 
     90 #ifdef NDEBUG
     91 #define	assert(e)	((void)0)
     92 #define	_assert(e)	((void)0)
     93 #else
     94 #define	_assert(e)	assert(e)
     95 #ifdef __STDC__
     96 #define	assert(e)	((e) ? (void)0 : __assert("sn ", __FILE__, __LINE__, #e))
     97 #else	/* PCC */
     98 #define	assert(e)	((e) ? (void)0 : __assert("sn "__FILE__, __LINE__, "e"))
     99 #endif
    100 #endif
    101 
    102 int sndebug = 0;
    103 
    104 /*
    105  * SONIC buffers need to be aligned 16 or 32 bit aligned.
    106  * These macros calculate and verify alignment.
    107  */
    108 #define	ROUNDUP(p, N)	(((int) p + N - 1) & ~(N - 1))
    109 
    110 #define SOALIGN(m, array)	(m ? (ROUNDUP(array, 4)) : (ROUNDUP(array, 2)))
    111 
    112 #define LOWER(x) ((unsigned)(x) & 0xffff)
    113 #define UPPER(x) ((unsigned)(x) >> 16)
    114 
    115 /*
    116  * Interface exists: make available by filling in network interface
    117  * record.  System will initialize the interface when it is ready
    118  * to accept packets.
    119  */
    120 int
    121 snsetup(sc, lladdr)
    122 	struct sn_softc	*sc;
    123 	u_int8_t *lladdr;
    124 {
    125 	struct ifnet *ifp = &sc->sc_if;
    126 	u_char	*p;
    127 	u_char	*pp;
    128 	int	i;
    129 
    130 	/*
    131 	 * XXX if_sn.c is intended to be MI. Should it allocate memory
    132 	 * for its descriptor areas, or expect the MD attach code
    133 	 * to do that?
    134 	 */
    135 	sc->space = malloc((SN_NPAGES + 1) * NBPG, M_DEVBUF, M_WAITOK);
    136 	if (sc->space == NULL) {
    137 		printf ("%s: memory allocation for descriptors failed\n",
    138 			sc->sc_dev.dv_xname);
    139 		return (1);
    140 	}
    141 
    142 	/*
    143 	 * Put the pup in reset mode (sninit() will fix it later),
    144 	 * stop the timer, disable all interrupts and clear any interrupts.
    145 	 */
    146 	NIC_PUT(sc, SNR_CR, CR_STP);
    147 	wbflush();
    148 	NIC_PUT(sc, SNR_CR, CR_RST);
    149 	wbflush();
    150 	NIC_PUT(sc, SNR_IMR, 0);
    151 	wbflush();
    152 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    153 	wbflush();
    154 
    155 	/*
    156 	 * because the SONIC is basically 16bit device it 'concatenates'
    157 	 * a higher buffer address to a 16 bit offset--this will cause wrap
    158 	 * around problems near the end of 64k !!
    159 	 */
    160 	p = sc->space;
    161 	pp = (u_char *)ROUNDUP ((int)p, NBPG);
    162 	p = pp;
    163 
    164 	/*
    165 	 * Disable caching on the SONIC's data space.
    166 	 * The pages might not be physically contiguous, so set
    167 	 * each page individually.
    168 	 */
    169 	for (i = 0; i < SN_NPAGES; i++) {
    170 		physaccess (p, (caddr_t)kvtop(p), NBPG, PG_V | PG_RW | PG_CI);
    171 		p += NBPG;
    172 	}
    173 	p = pp;
    174 
    175 	for (i = 0; i < NRRA; i++) {
    176 		sc->p_rra[i] = (void *)p;
    177 		sc->v_rra[i] = kvtop(p);
    178 		p += RXRSRC_SIZE(sc);
    179 	}
    180 	sc->v_rea = kvtop(p);
    181 
    182 	p = (u_char *)SOALIGN(sc, p);
    183 
    184 	sc->p_cda = (void *)(p);
    185 	sc->v_cda = kvtop(p);
    186 	p += CDA_SIZE(sc);
    187 
    188 	p = (u_char *)SOALIGN(sc, p);
    189 
    190 	for (i = 0; i < NTDA; i++) {
    191 		struct mtd *mtdp = &sc->mtda[i];
    192 		mtdp->mtd_txp = (void *)p;
    193 		mtdp->mtd_vtxp = kvtop(p);
    194 		p += TXP_SIZE(sc);
    195 	}
    196 
    197 	p = (u_char *)SOALIGN(sc, p);
    198 
    199 	if ((p - pp) > NBPG) {
    200 		printf ("%s: sizeof RRA (%ld) + CDA (%ld) +"
    201 		    "TDA (%ld) > NBPG (%d). Punt!\n",
    202 		    sc->sc_dev.dv_xname,
    203 		    (ulong)sc->p_cda - (ulong)sc->p_rra[0],
    204 		    (ulong)sc->mtda[0].mtd_txp - (ulong)sc->p_cda,
    205 		    (ulong)p - (ulong)sc->mtda[0].mtd_txp,
    206 		    NBPG);
    207 		return(1);
    208 	}
    209 
    210 	p = pp + NBPG;
    211 	pp = p;
    212 
    213 	if ((NRDA * RXPKT_SIZE(sc)) > NBPG) {
    214 		printf ("%s: sizeof NRDA (%d) > NBPG (%d). Punt!\n",
    215 			sc->sc_dev.dv_xname,
    216 			NRDA * RXPKT_SIZE(sc), NBPG);
    217 		return (1);
    218 	}
    219 
    220 	for (i = 0; i < NRDA; i++) {
    221 		sc->p_rda[i] = (void *) p;
    222 		sc->v_rda[i] = kvtop(p);
    223 		p += RXPKT_SIZE(sc);
    224 	}
    225 
    226 	p = (u_char *)SOALIGN(sc, p);
    227 
    228 	p = pp + NBPG;
    229 
    230 	for (i = 0; i < NRBA; i++) {
    231 		sc->rbuf[i] = (caddr_t)p;
    232 		p += NBPG;
    233 	}
    234 
    235 	for (i = 0; i < NTXB; i+=2) {
    236 		sc->tbuf[i] = (caddr_t)p;
    237 		sc->tbuf[i+1] = (caddr_t)(p + (NBPG/2));
    238 		sc->vtbuf[i] = kvtop(sc->tbuf[i]);
    239 		sc->vtbuf[i+1] = kvtop(sc->tbuf[i+1]);
    240 		p += NBPG;
    241 	}
    242 
    243 #ifdef DEBUG
    244 	camdump(sc);
    245 #endif
    246 	printf(" address %s\n", ether_sprintf(lladdr));
    247 
    248 #ifdef DEBUG
    249 	printf("%s: buffers: rra=%p cda=%p rda=%p tda=%p\n",
    250 	    sc->sc_dev.dv_xname, sc->p_rra[0], sc->p_cda,
    251 	    sc->p_rda[0], sc->mtda[0].mtd_txp);
    252 #endif
    253 
    254 	bcopy(sc->sc_dev.dv_xname, ifp->if_xname, IFNAMSIZ);
    255 	ifp->if_softc = sc;
    256 	ifp->if_ioctl = snioctl;
    257 	ifp->if_start = snstart;
    258 	ifp->if_flags =
    259 	    IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS | IFF_MULTICAST;
    260 	ifp->if_watchdog = snwatchdog;
    261 #if NBPFILTER > 0
    262 	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
    263 #endif
    264 	if_attach(ifp);
    265 	ether_ifattach(ifp, lladdr);
    266 
    267 	return (0);
    268 }
    269 
    270 static int
    271 snioctl(ifp, cmd, data)
    272 	struct ifnet *ifp;
    273 	u_long cmd;
    274 	caddr_t data;
    275 {
    276 	struct ifaddr *ifa;
    277 	struct ifreq *ifr;
    278 	struct sn_softc *sc = ifp->if_softc;
    279 	int	s = splnet(), err = 0;
    280 	int	temp;
    281 
    282 	switch (cmd) {
    283 
    284 	case SIOCSIFADDR:
    285 		ifa = (struct ifaddr *)data;
    286 		ifp->if_flags |= IFF_UP;
    287 		switch (ifa->ifa_addr->sa_family) {
    288 #ifdef INET
    289 		case AF_INET:
    290 			(void)sninit(ifp->if_softc);
    291 			arp_ifinit(ifp, ifa);
    292 			break;
    293 #endif
    294 		default:
    295 			(void)sninit(ifp->if_softc);
    296 			break;
    297 		}
    298 		break;
    299 
    300 	case SIOCSIFFLAGS:
    301 		if ((ifp->if_flags & IFF_UP) == 0 &&
    302 		    ifp->if_flags & IFF_RUNNING) {
    303 			snstop(ifp->if_softc);
    304 			ifp->if_flags &= ~IFF_RUNNING;
    305 		} else if (ifp->if_flags & IFF_UP &&
    306 		    (ifp->if_flags & IFF_RUNNING) == 0)
    307 			(void)sninit(ifp->if_softc);
    308 		/*
    309 		 * If the state of the promiscuous bit changes, the interface
    310 		 * must be reset to effect the change.
    311 		 */
    312 		if (((ifp->if_flags ^ sc->sc_iflags) & IFF_PROMISC) &&
    313 		    (ifp->if_flags & IFF_RUNNING)) {
    314 			sc->sc_iflags = ifp->if_flags;
    315 			printf("change in flags\n");
    316 			temp = sc->sc_if.if_flags & IFF_UP;
    317 			snreset(sc);
    318 			sc->sc_if.if_flags |= temp;
    319 			snstart(ifp);
    320 		}
    321 		break;
    322 
    323 	case SIOCADDMULTI:
    324 	case SIOCDELMULTI:
    325 		ifr = (struct ifreq *) data;
    326 		if (cmd == SIOCADDMULTI)
    327 			err = ether_addmulti(ifr, &sc->sc_ethercom);
    328 		else
    329 			err = ether_delmulti(ifr, &sc->sc_ethercom);
    330 
    331 		if (err == ENETRESET) {
    332 			/*
    333 			 * Multicast list has changed; set the hardware
    334 			 * filter accordingly. But remember UP flag!
    335 			 */
    336 			temp = sc->sc_if.if_flags & IFF_UP;
    337 			snreset(sc);
    338 			sc->sc_if.if_flags |= temp;
    339 			err = 0;
    340 		}
    341 		break;
    342 	default:
    343 		err = EINVAL;
    344 	}
    345 	splx(s);
    346 	return (err);
    347 }
    348 
    349 /*
    350  * Encapsulate a packet of type family for the local net.
    351  */
    352 static void
    353 snstart(ifp)
    354 	struct ifnet *ifp;
    355 {
    356 	struct sn_softc *sc = ifp->if_softc;
    357 	struct mbuf *m;
    358 	int	len;
    359 
    360 	if ((ifp->if_flags & (IFF_RUNNING | IFF_OACTIVE)) != IFF_RUNNING)
    361 		return;
    362 
    363 outloop:
    364 	/* Check for room in the xmit buffer. */
    365 	if (sc->txb_inuse == sc->txb_cnt) {
    366 		ifp->if_flags |= IFF_OACTIVE;
    367 		return;
    368 	}
    369 
    370 	IF_DEQUEUE(&ifp->if_snd, m);
    371 	if (m == 0)
    372 		return;
    373 
    374 	/* We need the header for m_pkthdr.len. */
    375 	if ((m->m_flags & M_PKTHDR) == 0)
    376 		panic("%s: snstart: no header mbuf", sc->sc_dev.dv_xname);
    377 
    378 #if NBPFILTER > 0
    379 	/*
    380 	 * If bpf is listening on this interface, let it
    381 	 * see the packet before we commit it to the wire.
    382 	 */
    383 	if (ifp->if_bpf)
    384 		bpf_mtap(ifp->if_bpf, m);
    385 #endif
    386 
    387 	/*
    388 	 * If there is nothing in the o/p queue, and there is room in
    389 	 * the Tx ring, then send the packet directly.  Otherwise append
    390 	 * it to the o/p queue.
    391 	 */
    392 	if ((len = sonicput(sc, m)) > 0) {
    393 		len = m->m_pkthdr.len;
    394 		m_freem(m);
    395 	} else {
    396 		IF_PREPEND(&ifp->if_snd, m);
    397 		return;
    398 	}
    399 
    400 	/* Point to next buffer slot and wrap if necessary. */
    401 	if (++sc->txb_new == sc->txb_cnt)
    402 		sc->txb_new = 0;
    403 
    404 	sc->txb_inuse++;
    405 
    406 	ifp->if_opackets++;		/* # of pkts */
    407 	sc->sc_sum.ls_opacks++;		/* # of pkts */
    408 
    409 	/* Jump back for possibly more punishment. */
    410 	goto outloop;
    411 }
    412 
    413 /*
    414  * reset and restart the SONIC.  Called in case of fatal
    415  * hardware/software errors.
    416  */
    417 static void
    418 snreset(sc)
    419 	struct sn_softc *sc;
    420 {
    421 	snstop(sc);
    422 	sninit(sc);
    423 }
    424 
    425 static int
    426 sninit(sc)
    427 	struct sn_softc *sc;
    428 {
    429 	u_long	s_rcr;
    430 	int	s;
    431 
    432 	if (sc->sc_if.if_flags & IFF_RUNNING)
    433 		/* already running */
    434 		return (0);
    435 
    436 	s = splnet();
    437 
    438 	NIC_PUT(sc, SNR_CR, CR_RST);	/* DCR only accessable in reset mode! */
    439 
    440 	/* config it */
    441 	NIC_PUT(sc, SNR_DCR, sc->snr_dcr);
    442 	NIC_PUT(sc, SNR_DCR2, sc->snr_dcr2);
    443 
    444 	s_rcr = RCR_BRD | RCR_LBNONE;
    445 	if (sc->sc_if.if_flags & IFF_PROMISC)
    446 		s_rcr |= RCR_PRO;
    447 	if (sc->sc_if.if_flags & IFF_ALLMULTI)
    448 		s_rcr |= RCR_AMC;
    449 	NIC_PUT(sc, SNR_RCR, s_rcr);
    450 
    451 	NIC_PUT(sc, SNR_IMR, (IMR_PRXEN | IMR_PTXEN | IMR_TXEREN | IMR_LCDEN));
    452 
    453 	/* clear pending interrupts */
    454 	NIC_PUT(sc, SNR_ISR, ISR_ALL);
    455 
    456 	/* clear tally counters */
    457 	NIC_PUT(sc, SNR_CRCT, -1);
    458 	NIC_PUT(sc, SNR_FAET, -1);
    459 	NIC_PUT(sc, SNR_MPT, -1);
    460 
    461 	initialise_tda(sc);
    462 	initialise_rda(sc);
    463 	initialise_rra(sc);
    464 	initialise_tba(sc);
    465 
    466 	/* enable the chip */
    467 	NIC_PUT(sc, SNR_CR, 0);
    468 	wbflush();
    469 
    470 	/* program the CAM */
    471 	camprogram(sc);
    472 
    473 	/* get it to read resource descriptors */
    474 	NIC_PUT(sc, SNR_CR, CR_RRRA);
    475 	wbflush();
    476 	while ((NIC_GET(sc, SNR_CR)) & CR_RRRA)
    477 		continue;
    478 
    479 	/* enable rx */
    480 	NIC_PUT(sc, SNR_CR, CR_RXEN);
    481 	wbflush();
    482 
    483 	/* flag interface as "running" */
    484 	sc->sc_if.if_flags |= IFF_RUNNING;
    485 
    486 	splx(s);
    487 	return (0);
    488 }
    489 
    490 /*
    491  * close down an interface and free its buffers
    492  * Called on final close of device, or if sninit() fails
    493  * part way through.
    494  */
    495 static int
    496 snstop(sc)
    497 	struct sn_softc *sc;
    498 {
    499 	struct mtd *mtd;
    500 	int	s = splnet();
    501 
    502 	/* stick chip in reset */
    503 	NIC_PUT(sc, SNR_CR, CR_RST);
    504 	wbflush();
    505 
    506 	/* free all receive buffers (currently static so nothing to do) */
    507 
    508 	/* free all pending transmit mbufs */
    509 	while (sc->mtd_hw != sc->mtd_free) {
    510 		mtd = &sc->mtda[sc->mtd_hw];
    511 		mtd->mtd_buf = 0;
    512 		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
    513 	}
    514 	sc->txb_inuse = 0;
    515 
    516 	sc->sc_if.if_timer = 0;
    517 	sc->sc_if.if_flags &= ~(IFF_RUNNING | IFF_UP);
    518 
    519 	splx(s);
    520 	return (0);
    521 }
    522 
    523 /*
    524  * Called if any Tx packets remain unsent after 5 seconds,
    525  * In all cases we just reset the chip, and any retransmission
    526  * will be handled by higher level protocol timeouts.
    527  */
    528 static void
    529 snwatchdog(ifp)
    530 	struct ifnet *ifp;
    531 {
    532 	struct sn_softc *sc = ifp->if_softc;
    533 	struct mtd *mtd;
    534 	int	temp;
    535 
    536 	if (sc->mtd_hw != sc->mtd_free) {
    537 		/* something still pending for transmit */
    538 		mtd = &sc->mtda[sc->mtd_hw];
    539 		if (SRO(sc->bitmode, mtd->mtd_txp, TXP_STATUS) == 0)
    540 			log(LOG_ERR, "%s: Tx - timeout\n",
    541 			    sc->sc_dev.dv_xname);
    542 		else
    543 			log(LOG_ERR, "%s: Tx - lost interrupt\n",
    544 			    sc->sc_dev.dv_xname);
    545 		temp = ifp->if_flags & IFF_UP;
    546 		snreset(sc);
    547 		ifp->if_flags |= temp;
    548 	}
    549 }
    550 
    551 /*
    552  * stuff packet into sonic (at splnet)
    553  */
    554 static __inline__ int
    555 sonicput(sc, m0)
    556 	struct sn_softc *sc;
    557 	struct mbuf *m0;
    558 {
    559 	struct mtd *mtdp;
    560 	struct mbuf *m;
    561 	u_char	*buff, *buffer;
    562 	void	*txp;
    563 	u_int	len = 0;
    564 	u_int	totlen = 0;
    565 	int	mtd_free = sc->mtd_free;
    566 	int	mtd_next;
    567 	int	txb_new = sc->txb_new;
    568 
    569 	if (NIC_GET(sc, SNR_CR) & CR_TXP)
    570 		return (0);
    571 
    572 	/* grab the replacement mtd */
    573 	mtdp = &sc->mtda[mtd_free];
    574 
    575 	if ((mtd_next = mtd_free + 1) == NTDA)
    576 		mtd_next = 0;
    577 
    578 	if (mtd_next == sc->mtd_hw)
    579 		return (0);
    580 
    581 	/* We are guaranteed, if we get here, that the xmit buffer is free. */
    582 	buff = buffer = sc->tbuf[txb_new];
    583 
    584 	/* this packet goes to mtdnext fill in the TDA */
    585 	mtdp->mtd_buf = buffer;
    586 	txp = mtdp->mtd_txp;
    587 	SWO(sc->bitmode, txp, TXP_CONFIG, 0);
    588 
    589 	for (m = m0; m; m = m->m_next) {
    590 		u_char *data = mtod(m, u_char *);
    591 		len = m->m_len;
    592 		totlen += len;
    593 		bcopy(data, buff, len);
    594 		buff += len;
    595 	}
    596 	if (totlen >= TXBSIZE) {
    597 		panic("%s: sonicput: packet overflow", sc->sc_dev.dv_xname);
    598 	}
    599 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRLO,
    600 	    LOWER(sc->vtbuf[txb_new]));
    601 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRHI,
    602 	    UPPER(sc->vtbuf[txb_new]));
    603 
    604 	if (totlen < ETHERMIN + sizeof(struct ether_header)) {
    605 		int pad = ETHERMIN + sizeof(struct ether_header) - totlen;
    606 		bzero(buffer + totlen, pad);
    607 		totlen = ETHERMIN + sizeof(struct ether_header);
    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 	sc->mtd_prev = mtd_free;
    628 	sc->mtd_free = mtd_next;
    629 
    630 	/* make sure chip is running */
    631 	wbflush();
    632 	NIC_PUT(sc, SNR_CR, CR_TXP);
    633 	wbflush();
    634 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
    635 
    636 	return (totlen);
    637 }
    638 
    639 /*
    640  * These are called from sonicioctl() when /etc/ifconfig is run to set
    641  * the address or switch the i/f on.
    642  */
    643 /*
    644  * CAM support
    645  */
    646 static void
    647 caminitialise(sc)
    648 	struct sn_softc *sc;
    649 {
    650 	void	*p_cda = sc->p_cda;
    651 	int	i;
    652 	int	bitmode = sc->bitmode;
    653 	int	camoffset;
    654 
    655 	for (i = 0; i < MAXCAM; i++) {
    656 		camoffset = i * CDA_CAMDESC;
    657 		SWO(bitmode, p_cda, (camoffset + CDA_CAMEP), i);
    658 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP2), 0);
    659 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP1), 0);
    660 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP0), 0);
    661 	}
    662 	SWO(bitmode, p_cda, CDA_ENABLE, 0);
    663 }
    664 
    665 static void
    666 camentry(sc, entry, ea)
    667 	int entry;
    668 	u_char *ea;
    669 	struct sn_softc *sc;
    670 {
    671 	void	*p_cda = sc->p_cda;
    672 	int	bitmode = sc->bitmode;
    673 	int	camoffset = entry * CDA_CAMDESC;
    674 
    675 	SWO(bitmode, p_cda, camoffset + CDA_CAMEP, entry);
    676 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP2, (ea[5] << 8) | ea[4]);
    677 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP1, (ea[3] << 8) | ea[2]);
    678 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP0, (ea[1] << 8) | ea[0]);
    679 	SWO(bitmode, p_cda, CDA_ENABLE,
    680 	    (SRO(bitmode, p_cda, CDA_ENABLE) | (1 << entry)));
    681 }
    682 
    683 static void
    684 camprogram(sc)
    685 	struct sn_softc *sc;
    686 {
    687 	struct ether_multistep step;
    688 	struct ether_multi *enm;
    689 	struct ifnet *ifp;
    690 	int	timeout;
    691 	int	mcount = 0;
    692 
    693 	caminitialise(sc);
    694 
    695 	ifp = &sc->sc_if;
    696 
    697 	/* Always load our own address first. */
    698 	camentry (sc, mcount, LLADDR(ifp->if_sadl));
    699 	mcount++;
    700 
    701 	/* Assume we won't need allmulti bit. */
    702 	ifp->if_flags &= ~IFF_ALLMULTI;
    703 
    704 	/* Loop through multicast addresses */
    705 	ETHER_FIRST_MULTI(step, &sc->sc_ethercom, enm);
    706 	while (enm != NULL) {
    707 		if (mcount == MAXCAM) {
    708 			 ifp->if_flags |= IFF_ALLMULTI;
    709 			 break;
    710 		}
    711 
    712 		if (bcmp(enm->enm_addrlo, enm->enm_addrhi,
    713 		    sizeof(enm->enm_addrlo)) != 0) {
    714 			/*
    715 			 * SONIC's CAM is programmed with specific
    716 			 * addresses. It has no way to specify a range.
    717 			 * (Well, thats not exactly true. If the
    718 			 * range is small one could program each addr
    719 			 * within the range as a seperate CAM entry)
    720 			 */
    721 			ifp->if_flags |= IFF_ALLMULTI;
    722 			break;
    723 		}
    724 
    725 		/* program the CAM with the specified entry */
    726 		camentry(sc, mcount, enm->enm_addrlo);
    727 		mcount++;
    728 
    729 		ETHER_NEXT_MULTI(step, enm);
    730 	}
    731 
    732 	NIC_PUT(sc, SNR_CDP, LOWER(sc->v_cda));
    733 	NIC_PUT(sc, SNR_CDC, MAXCAM);
    734 	NIC_PUT(sc, SNR_CR, CR_LCAM);
    735 	wbflush();
    736 
    737 	timeout = 10000;
    738 	while ((NIC_GET(sc, SNR_CR) & CR_LCAM) && timeout--)
    739 		continue;
    740 	if (timeout == 0) {
    741 		/* XXX */
    742 		panic("%s: CAM initialisation failed\n", sc->sc_dev.dv_xname);
    743 	}
    744 	timeout = 10000;
    745 	while (((NIC_GET(sc, SNR_ISR) & ISR_LCD) == 0) && timeout--)
    746 		continue;
    747 
    748 	if (NIC_GET(sc, SNR_ISR) & ISR_LCD)
    749 		NIC_PUT(sc, SNR_ISR, ISR_LCD);
    750 	else
    751 		printf("%s: CAM initialisation without interrupt\n",
    752 		    sc->sc_dev.dv_xname);
    753 }
    754 
    755 #ifdef DEBUG
    756 static void
    757 camdump(sc)
    758 	struct sn_softc *sc;
    759 {
    760 	int	i;
    761 
    762 	printf("CAM entries:\n");
    763 	NIC_PUT(sc, SNR_CR, CR_RST);
    764 	wbflush();
    765 
    766 	for (i = 0; i < 16; i++) {
    767 		ushort  ap2, ap1, ap0;
    768 		NIC_PUT(sc, SNR_CEP, i);
    769 		wbflush();
    770 		ap2 = NIC_GET(sc, SNR_CAP2);
    771 		ap1 = NIC_GET(sc, SNR_CAP1);
    772 		ap0 = NIC_GET(sc, SNR_CAP0);
    773 		printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
    774 	}
    775 	printf("CAM enable 0x%x\n", NIC_GET(sc, SNR_CEP));
    776 
    777 	NIC_PUT(sc, SNR_CR, 0);
    778 	wbflush();
    779 }
    780 #endif
    781 
    782 static void
    783 initialise_tda(sc)
    784 	struct sn_softc *sc;
    785 {
    786 	struct mtd *mtd;
    787 	int	i;
    788 
    789 	for (i = 0; i < NTDA; i++) {
    790 		mtd = &sc->mtda[i];
    791 		mtd->mtd_buf = 0;
    792 	}
    793 
    794 	sc->mtd_hw = 0;
    795 	sc->mtd_prev = NTDA - 1;
    796 	sc->mtd_free = 0;
    797 	sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;
    798 
    799 	NIC_PUT(sc, SNR_UTDA, UPPER(sc->mtda[0].mtd_vtxp));
    800 	NIC_PUT(sc, SNR_CTDA, LOWER(sc->mtda[0].mtd_vtxp));
    801 }
    802 
    803 static void
    804 initialise_rda(sc)
    805 	struct sn_softc *sc;
    806 {
    807 	int	bitmode = sc->bitmode;
    808 	int	i;
    809 
    810 	/* link the RDA's together into a circular list */
    811 	for (i = 0; i < (NRDA - 1); i++) {
    812 		SWO(bitmode, sc->p_rda[i], RXPKT_RLINK, LOWER(sc->v_rda[i+1]));
    813 		SWO(bitmode, sc->p_rda[i], RXPKT_INUSE, 1);
    814 	}
    815 	SWO(bitmode, sc->p_rda[NRDA - 1], RXPKT_RLINK,
    816 	    LOWER(sc->v_rda[0]) | EOL);
    817 	SWO(bitmode, sc->p_rda[NRDA - 1], RXPKT_INUSE, 1);
    818 
    819 	/* mark end of receive descriptor list */
    820 	sc->sc_rdamark = NRDA - 1;
    821 
    822 	sc->sc_rxmark = 0;
    823 
    824 	NIC_PUT(sc, SNR_URDA, UPPER(sc->v_rda[0]));
    825 	NIC_PUT(sc, SNR_CRDA, LOWER(sc->v_rda[0]));
    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 = kvtop(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 static void
    863 initialise_tba(sc)
    864 	struct sn_softc *sc;
    865 {
    866 	sc->txb_cnt = NTXB;
    867 	sc->txb_inuse = 0;
    868 	sc->txb_new = 0;
    869 }
    870 
    871 void
    872 snintr(arg, slot)
    873 	void	*arg;
    874 	int	slot;
    875 {
    876 	struct sn_softc *sc = (struct sn_softc *)arg;
    877 	int	isr;
    878 
    879 	while ((isr = (NIC_GET(sc, SNR_ISR) & ISR_ALL)) != 0) {
    880 		/* scrub the interrupts that we are going to service */
    881 		NIC_PUT(sc, SNR_ISR, isr);
    882 		wbflush();
    883 
    884 		if (isr & (ISR_BR | ISR_LCD | ISR_TC))
    885 			printf("%s: unexpected interrupt status 0x%x\n",
    886 			    sc->sc_dev.dv_xname, isr);
    887 
    888 		if (isr & (ISR_TXDN | ISR_TXER | ISR_PINT))
    889 			sonictxint(sc);
    890 
    891 		if (isr & ISR_PKTRX)
    892 			sonicrxint(sc);
    893 
    894 		if (isr & (ISR_HBL | ISR_RDE | ISR_RBE | ISR_RBAE | ISR_RFO)) {
    895 			if (isr & ISR_HBL)
    896 				/*
    897 				 * The repeater is not providing a heartbeat.
    898 				 * In itself this isn't harmful, lots of the
    899 				 * cheap repeater hubs don't supply a heartbeat.
    900 				 * So ignore the lack of heartbeat. Its only
    901 				 * if we can't detect a carrier that we have a
    902 				 * problem.
    903 				 */
    904 				;
    905 			if (isr & ISR_RDE)
    906 				printf("%s: receive descriptors exhausted\n",
    907 				    sc->sc_dev.dv_xname);
    908 			if (isr & ISR_RBE)
    909 				printf("%s: receive buffers exhausted\n",
    910 				    sc->sc_dev.dv_xname);
    911 			if (isr & ISR_RBAE)
    912 				printf("%s: receive buffer area exhausted\n",
    913 				    sc->sc_dev.dv_xname);
    914 			if (isr & ISR_RFO)
    915 				printf("%s: receive FIFO overrun\n",
    916 				    sc->sc_dev.dv_xname);
    917 		}
    918 		if (isr & (ISR_CRC | ISR_FAE | ISR_MP)) {
    919 #ifdef notdef
    920 			if (isr & ISR_CRC)
    921 				sc->sc_crctally++;
    922 			if (isr & ISR_FAE)
    923 				sc->sc_faetally++;
    924 			if (isr & ISR_MP)
    925 				sc->sc_mptally++;
    926 #endif
    927 		}
    928 		snstart(&sc->sc_if);
    929 	}
    930 	return;
    931 }
    932 
    933 /*
    934  * Transmit interrupt routine
    935  */
    936 static void
    937 sonictxint(sc)
    938 	struct sn_softc *sc;
    939 {
    940 	struct mtd *mtd;
    941 	void	*txp;
    942 	/* XXX DG make mtd_hw a local var */
    943 
    944 	if (sc->mtd_hw == sc->mtd_free)
    945 		return;
    946 
    947 	while (sc->mtd_hw != sc->mtd_free) {
    948 		mtd = &sc->mtda[sc->mtd_hw];
    949 		if (mtd->mtd_buf == 0)
    950 			break;
    951 
    952 		txp = mtd->mtd_txp;
    953 
    954 		if (SRO(sc->bitmode, txp, TXP_STATUS) == 0)
    955 			return; /* it hasn't really gone yet */
    956 
    957 		if (sndebug) {
    958 			struct ether_header *eh;
    959 
    960 			eh = (struct ether_header *) mtd->mtd_buf;
    961 			printf("%s: xmit status=0x%x len=%d type=0x%x from %s",
    962 			    sc->sc_dev.dv_xname,
    963 			    SRO(sc->bitmode, txp, TXP_STATUS),
    964 			    SRO(sc->bitmode, txp, TXP_PKTSIZE),
    965 			    htons(eh->ether_type),
    966 			    ether_sprintf(eh->ether_shost));
    967 			printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
    968 		}
    969 		sc->txb_inuse--;
    970 		mtd->mtd_buf = 0;
    971 		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
    972 
    973 		/* XXX - Do stats here. */
    974 
    975 		if ((SRO(sc->bitmode, txp, TXP_STATUS) & TCR_PTX) == 0) {
    976 			printf("%s: Tx packet status=0x%x\n",
    977 			    sc->sc_dev.dv_xname,
    978 			    SRO(sc->bitmode, txp, TXP_STATUS));
    979 
    980 			/* XXX - DG This looks bogus */
    981 			if (sc->mtd_hw != sc->mtd_free) {
    982 				printf("resubmitting remaining packets\n");
    983 				mtd = &sc->mtda[sc->mtd_hw];
    984 				NIC_PUT(sc, SNR_CTDA, LOWER(mtd->mtd_vtxp));
    985 				NIC_PUT(sc, SNR_CR, CR_TXP);
    986 				wbflush();
    987 				return;
    988 			}
    989 		}
    990 	}
    991 }
    992 
    993 /*
    994  * Receive interrupt routine
    995  */
    996 static void
    997 sonicrxint(sc)
    998 	struct sn_softc *sc;
    999 {
   1000 	void	*rda;
   1001 	int	orra;
   1002 	int	len;
   1003 	int	rramark;
   1004 	int	rdamark;
   1005 	int	bitmode = sc->bitmode;
   1006 	u_int16_t rxpkt_ptr;
   1007 
   1008 	rda = sc->p_rda[sc->sc_rxmark];
   1009 
   1010 	while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
   1011 		u_int status = SRO(bitmode, rda, RXPKT_STATUS);
   1012 
   1013 		orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
   1014 		rxpkt_ptr = SRO(bitmode, rda, RXPKT_PTRLO);
   1015 		len = SRO(bitmode, rda, RXPKT_BYTEC) -
   1016 			sizeof(struct ether_header) - FCSSIZE;
   1017 		if (status & RCR_PRX) {
   1018 			caddr_t pkt =
   1019 			    sc->rbuf[orra & RBAMASK] + (rxpkt_ptr & PGOFSET);
   1020 			if (sonic_read(sc, pkt, len)) {
   1021 				sc->sc_if.if_ipackets++;
   1022 				sc->sc_sum.ls_ipacks++;
   1023 				sc->sc_missed = 0;
   1024 			}
   1025 		} else
   1026 			sc->sc_if.if_ierrors++;
   1027 
   1028 		/*
   1029 		 * give receive buffer area back to chip.
   1030 		 *
   1031 		 * If this was the last packet in the RRA, give the RRA to
   1032 		 * the chip again.
   1033 		 * If sonic read didnt copy it out then we would have to
   1034 		 * wait !!
   1035 		 * (dont bother add it back in again straight away)
   1036 		 *
   1037 		 * Really, we're doing p_rra[rramark] = p_rra[orra] but
   1038 		 * we have to use the macros because SONIC might be in
   1039 		 * 16 or 32 bit mode.
   1040 		 */
   1041 		if (status & RCR_LPKT) {
   1042 			void *tmp1, *tmp2;
   1043 
   1044 			rramark = sc->sc_rramark;
   1045 			tmp1 = sc->p_rra[rramark];
   1046 			tmp2 = sc->p_rra[orra];
   1047 			SWO(bitmode, tmp1, RXRSRC_PTRLO,
   1048 				SRO(bitmode, tmp2, RXRSRC_PTRLO));
   1049 			SWO(bitmode, tmp1, RXRSRC_PTRHI,
   1050 				SRO(bitmode, tmp2, RXRSRC_PTRHI));
   1051 			SWO(bitmode, tmp1, RXRSRC_WCLO,
   1052 				SRO(bitmode, tmp2, RXRSRC_WCLO));
   1053 			SWO(bitmode, tmp1, RXRSRC_WCHI,
   1054 				SRO(bitmode, tmp2, RXRSRC_WCHI));
   1055 
   1056 			/* zap old rra for fun */
   1057 			SWO(bitmode, tmp2, RXRSRC_WCHI, 0);
   1058 			SWO(bitmode, tmp2, RXRSRC_WCLO, 0);
   1059 
   1060 			sc->sc_rramark = (++rramark) & RRAMASK;
   1061 			NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[rramark]));
   1062 			wbflush();
   1063 		}
   1064 
   1065 		/*
   1066 		 * give receive descriptor back to chip simple
   1067 		 * list is circular
   1068 		 */
   1069 		rdamark = sc->sc_rdamark;
   1070 		SWO(bitmode, rda, RXPKT_INUSE, 1);
   1071 		SWO(bitmode, rda, RXPKT_RLINK,
   1072 			SRO(bitmode, rda, RXPKT_RLINK) | EOL);
   1073 		SWO(bitmode, sc->p_rda[rdamark], RXPKT_RLINK,
   1074 			SRO(bitmode, sc->p_rda[rdamark], RXPKT_RLINK) & ~EOL);
   1075 		sc->sc_rdamark = sc->sc_rxmark;
   1076 
   1077 		if (++sc->sc_rxmark >= NRDA)
   1078 			sc->sc_rxmark = 0;
   1079 		rda = sc->p_rda[sc->sc_rxmark];
   1080 	}
   1081 }
   1082 
   1083 /*
   1084  * sonic_read -- pull packet off interface and forward to
   1085  * appropriate protocol handler
   1086  */
   1087 static __inline__ int
   1088 sonic_read(sc, pkt, len)
   1089 	struct sn_softc *sc;
   1090 	caddr_t pkt;
   1091 	int len;
   1092 {
   1093 	struct ifnet *ifp = &sc->sc_if;
   1094 	struct ether_header *et;
   1095 	struct mbuf *m;
   1096 
   1097 	/*
   1098 	 * Get pointer to ethernet header (in input buffer).
   1099 	 */
   1100 	et = (struct ether_header *)pkt;
   1101 
   1102 	if (sndebug) {
   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 	if (len < ETHERMIN || len > ETHERMTU) {
   1109 		printf("%s: invalid packet length %d bytes\n",
   1110 		    sc->sc_dev.dv_xname, len);
   1111 		return (0);
   1112 	}
   1113 
   1114 #if NBPFILTER > 0
   1115 	/*
   1116 	 * Check if there's a bpf filter listening on this interface.
   1117 	 * If so, hand off the raw packet to enet, then discard things
   1118 	 * not destined for us (but be sure to keep broadcast/multicast).
   1119 	 */
   1120 	if (ifp->if_bpf) {
   1121 		bpf_tap(ifp->if_bpf, pkt,
   1122 		    len + sizeof(struct ether_header));
   1123 		if ((ifp->if_flags & IFF_PROMISC) != 0 &&
   1124 		    (et->ether_dhost[0] & 1) == 0 && /* !mcast and !bcast */
   1125 		    bcmp(et->ether_dhost, LLADDR(ifp->if_sadl),
   1126 		    sizeof(et->ether_dhost)) != 0)
   1127 			return (0);
   1128 	}
   1129 #endif
   1130 	m = sonic_get(sc, et, len);
   1131 	if (m == NULL)
   1132 		return (0);
   1133 	ether_input(ifp, et, m);
   1134 	return (1);
   1135 }
   1136 
   1137 #define sonicdataaddr(eh, off, type)	((type)(((caddr_t)((eh) + 1) + (off))))
   1138 
   1139 /*
   1140  * munge the received packet into an mbuf chain
   1141  * because we are using stupid buffer management this
   1142  * is slow.
   1143  */
   1144 static __inline__ struct mbuf *
   1145 sonic_get(sc, eh, datalen)
   1146 	struct sn_softc *sc;
   1147 	struct ether_header *eh;
   1148 	int datalen;
   1149 {
   1150 	struct mbuf *m;
   1151 	struct mbuf *top = 0, **mp = &top;
   1152 	int	len;
   1153 	char	*spkt = sonicdataaddr(eh, 0, caddr_t);
   1154 	char	*epkt = spkt + datalen;
   1155 	char	*cp = spkt;
   1156 
   1157 	epkt = cp + datalen;
   1158 	MGETHDR(m, M_DONTWAIT, MT_DATA);
   1159 	if (m == 0)
   1160 		return (0);
   1161 	m->m_pkthdr.rcvif = &sc->sc_if;
   1162 	m->m_pkthdr.len = datalen;
   1163 	m->m_len = MHLEN;
   1164 
   1165 	while (datalen > 0) {
   1166 		if (top) {
   1167 			MGET(m, M_DONTWAIT, MT_DATA);
   1168 			if (m == 0) {
   1169 				m_freem(top);
   1170 				return (0);
   1171 			}
   1172 			m->m_len = MLEN;
   1173 		}
   1174 		len = min(datalen, epkt - cp);
   1175 		if (len >= MINCLSIZE) {
   1176 			MCLGET(m, M_DONTWAIT);
   1177 			if (m->m_flags & M_EXT)
   1178 				m->m_len = len = min(len, MCLBYTES);
   1179 			else
   1180 				len = m->m_len;
   1181 		} else {
   1182 			/*
   1183 			 * Place initial small packet/header at end of mbuf.
   1184 			 */
   1185 			if (len < m->m_len) {
   1186 				if (top == 0 && len + max_linkhdr <= m->m_len)
   1187 					m->m_data += max_linkhdr;
   1188 				m->m_len = len;
   1189 			} else
   1190 				len = m->m_len;
   1191 		}
   1192 		bcopy(cp, mtod(m, caddr_t), (unsigned)len);
   1193 		cp += len;
   1194 		*mp = m;
   1195 		mp = &m->m_next;
   1196 		datalen -= len;
   1197 		if (cp == epkt)
   1198 			cp = spkt;
   1199 	}
   1200 	return (top);
   1201 }
   1202 
   1203 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
   1204 #define bbr(v)	((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
   1205 
   1206 void
   1207 sn_get_enaddr(t, h, o, dst)
   1208 	bus_space_tag_t	t;
   1209 	bus_space_handle_t h;
   1210 	vm_offset_t o;
   1211 	u_char *dst;
   1212 {
   1213 	int	i, do_bbr;
   1214 	u_char	b;
   1215 
   1216 	/*
   1217 	 * For reasons known only to Apple, MAC addresses in the ethernet
   1218 	 * PROM are stored in Token Ring (IEEE 802.5) format, that is
   1219 	 * with all of the bits in each byte reversed (canonical bit format).
   1220 	 * When the address is read out it must be reversed to ethernet format
   1221 	 * before use.
   1222 	 *
   1223 	 * Apple has been assigned OUI's 08:00:07 and 00:a0:40. All onboard
   1224 	 * ethernet addresses on 68K machines should be in one of these
   1225 	 * two ranges.
   1226 	 *
   1227 	 * Here is where it gets complicated.
   1228 	 *
   1229 	 * The PMac 7200, 7500, 8500, and 9500 accidentally had the PROM
   1230 	 * written in standard ethernet format. The MacOS accounted for this
   1231 	 * in these systems, and did not reverse the bytes. Some other
   1232 	 * networking utilities were not so forgiving, and got confused.
   1233 	 * "Some" of Apple's Nubus ethernet cards also had their bits
   1234 	 * burned in ethernet format.
   1235 	 *
   1236 	 * Apple petitioned the IEEE and was granted the 00:05:02 (bit reversal
   1237 	 * of 00:a0:40) as well. As of OpenTransport 1.1.1, Apple removed
   1238 	 * their workaround and now reverses the bits regardless of
   1239 	 * what kind of machine it is. So PMac systems and the affected
   1240 	 * Nubus cards now use 00:05:02, instead of the 00:a0:40 for which they
   1241 	 * were intended.
   1242 	 *
   1243 	 * See Apple Techinfo article TECHINFO-0020552, "OpenTransport 1.1.1
   1244 	 * and MacOS System 7.5.3 FAQ (10/96)" for more details.
   1245 	 */
   1246 	do_bbr = 0;
   1247 	b = bus_space_read_1(t, h, o);
   1248 	if (b == 0x10)
   1249 		do_bbr = 1;
   1250 	dst[0] = (do_bbr) ? bbr(b) : b;
   1251 
   1252 	for (i = 1 ; i < ETHER_ADDR_LEN ; i++) {
   1253 		b = bus_space_read_1(t, h, o+i);
   1254 		dst[i] = (do_bbr) ? bbr(b) : b;
   1255 	}
   1256 }
   1257