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if_sn.c revision 1.36
      1 /*	$NetBSD: if_sn.c,v 1.36 2005/01/15 16:00:59 chs 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 <sys/cdefs.h>
     19 __KERNEL_RCSID(0, "$NetBSD: if_sn.c,v 1.36 2005/01/15 16:00:59 chs Exp $");
     20 
     21 #include "opt_inet.h"
     22 
     23 #include <sys/param.h>
     24 #include <sys/systm.h>
     25 #include <sys/mbuf.h>
     26 #include <sys/buf.h>
     27 #include <sys/protosw.h>
     28 #include <sys/socket.h>
     29 #include <sys/syslog.h>
     30 #include <sys/ioctl.h>
     31 #include <sys/errno.h>
     32 #include <sys/device.h>
     33 
     34 #include <uvm/uvm_extern.h>
     35 
     36 #include <net/if.h>
     37 #include <net/if_dl.h>
     38 #include <net/if_ether.h>
     39 
     40 #ifdef INET
     41 #include <netinet/in.h>
     42 #include <netinet/in_systm.h>
     43 #include <netinet/in_var.h>
     44 #include <netinet/ip.h>
     45 #include <netinet/if_inarp.h>
     46 #endif
     47 
     48 #include <uvm/uvm_extern.h>
     49 
     50 #include "bpfilter.h"
     51 #if NBPFILTER > 0
     52 #include <net/bpf.h>
     53 #include <net/bpfdesc.h>
     54 #endif
     55 
     56 #include <machine/bus.h>
     57 #include <machine/cpu.h>
     58 #include <machine/viareg.h>
     59 #include <mac68k/dev/if_snreg.h>
     60 #include <mac68k/dev/if_snvar.h>
     61 
     62 static void	snwatchdog(struct ifnet *);
     63 static int	sninit(struct sn_softc *);
     64 static int	snstop(struct sn_softc *);
     65 static int	snioctl(struct ifnet *, u_long, caddr_t);
     66 static void	snstart(struct ifnet *);
     67 static void	snreset(struct sn_softc *);
     68 
     69 static void	caminitialise(struct sn_softc *);
     70 static void	camentry(struct sn_softc *, int, u_char *);
     71 static void	camprogram(struct sn_softc *);
     72 static void	initialise_tda(struct sn_softc *);
     73 static void	initialise_rda(struct sn_softc *);
     74 static void	initialise_rra(struct sn_softc *);
     75 #ifdef SNDEBUG
     76 static void	camdump(struct sn_softc *);
     77 #endif
     78 
     79 static void	sonictxint(struct sn_softc *);
     80 static void	sonicrxint(struct sn_softc *);
     81 
     82 static __inline__ u_int	sonicput(struct sn_softc *, struct mbuf *, int);
     83 static __inline__ int	sonic_read(struct sn_softc *, caddr_t, int);
     84 static __inline__ struct mbuf *sonic_get(struct sn_softc *, caddr_t, int);
     85 
     86 #undef assert
     87 #undef _assert
     88 
     89 #ifdef NDEBUG
     90 #define	assert(e)	((void)0)
     91 #define	_assert(e)	((void)0)
     92 #else
     93 #define	_assert(e)	assert(e)
     94 #ifdef __STDC__
     95 #define	assert(e)	((e) ? (void)0 : __assert("sn ", __FILE__, __LINE__, #e))
     96 #else	/* PCC */
     97 #define	assert(e)	((e) ? (void)0 : __assert("sn "__FILE__, __LINE__, "e"))
     98 #endif
     99 #endif
    100 
    101 int sndebug = 0;
    102 
    103 /*
    104  * SONIC buffers need to be aligned 16 or 32 bit aligned.
    105  * These macros calculate and verify alignment.
    106  */
    107 #define	ROUNDUP(p, N)	(((int) p + N - 1) & ~(N - 1))
    108 
    109 #define SOALIGN(m, array)	(m ? (ROUNDUP(array, 4)) : (ROUNDUP(array, 2)))
    110 
    111 #define LOWER(x) ((unsigned)(x) & 0xffff)
    112 #define UPPER(x) ((unsigned)(x) >> 16)
    113 
    114 /*
    115  * Interface exists: make available by filling in network interface
    116  * record.  System will initialize the interface when it is ready
    117  * to accept packets.
    118  */
    119 int
    120 snsetup(struct sn_softc	*sc, 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 	memcpy(ifp->if_xname, sc->sc_dev.dv_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(struct ifnet *ifp, u_long cmd, caddr_t data)
    268 {
    269 	struct ifaddr *ifa;
    270 	struct ifreq *ifr;
    271 	struct sn_softc *sc = ifp->if_softc;
    272 	int s, err = 0;
    273 	int temp;
    274 
    275 	s = splnet();
    276 
    277 	switch (cmd) {
    278 
    279 	case SIOCSIFADDR:
    280 		ifa = (struct ifaddr *)data;
    281 		ifp->if_flags |= IFF_UP;
    282 		switch (ifa->ifa_addr->sa_family) {
    283 #ifdef INET
    284 		case AF_INET:
    285 			(void)sninit(sc);
    286 			arp_ifinit(ifp, ifa);
    287 			break;
    288 #endif
    289 		default:
    290 			(void)sninit(sc);
    291 			break;
    292 		}
    293 		break;
    294 
    295 	case SIOCSIFFLAGS:
    296 		if ((ifp->if_flags & IFF_UP) == 0 &&
    297 		    (ifp->if_flags & IFF_RUNNING) != 0) {
    298 			/*
    299 			 * If interface is marked down and it is running,
    300 			 * then stop it.
    301 			 */
    302 			snstop(sc);
    303 			ifp->if_flags &= ~IFF_RUNNING;
    304 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
    305 		    (ifp->if_flags & IFF_RUNNING) == 0) {
    306 			/*
    307 			 * If interface is marked up and it is stopped,
    308 			 * then start it.
    309 			 */
    310 			(void)sninit(sc);
    311 		} else {
    312 			/*
    313 			 * reset the interface to pick up any other changes
    314 			 * in flags
    315 			 */
    316 			temp = ifp->if_flags & IFF_UP;
    317 			snreset(sc);
    318 			ifp->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 			if (ifp->if_flags & IFF_RUNNING) {
    337 				temp = ifp->if_flags & IFF_UP;
    338 				snreset(sc);
    339 				ifp->if_flags |= temp;
    340 			}
    341 			err = 0;
    342 		}
    343 		break;
    344 	default:
    345 		err = EINVAL;
    346 	}
    347 	splx(s);
    348 	return (err);
    349 }
    350 
    351 /*
    352  * Encapsulate a packet of type family for the local net.
    353  */
    354 static void
    355 snstart(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(struct sn_softc *sc)
    416 {
    417 	snstop(sc);
    418 	sninit(sc);
    419 }
    420 
    421 static int
    422 sninit(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(struct sn_softc *sc)
    493 {
    494 	struct mtd *mtd;
    495 	int s;
    496 
    497 	s = splnet();
    498 
    499 	/* stick chip in reset */
    500 	NIC_PUT(sc, SNR_CR, CR_RST);
    501 	wbflush();
    502 
    503 	/* free all receive buffers (currently static so nothing to do) */
    504 
    505 	/* free all pending transmit mbufs */
    506 	while (sc->mtd_hw != sc->mtd_free) {
    507 		mtd = &sc->mtda[sc->mtd_hw];
    508 		if (mtd->mtd_mbuf)
    509 			m_freem(mtd->mtd_mbuf);
    510 		if (++sc->mtd_hw == NTDA) sc->mtd_hw = 0;
    511 	}
    512 
    513 	sc->sc_if.if_timer = 0;
    514 	sc->sc_if.if_flags &= ~(IFF_RUNNING | IFF_UP);
    515 
    516 	splx(s);
    517 	return (0);
    518 }
    519 
    520 /*
    521  * Called if any Tx packets remain unsent after 5 seconds,
    522  * In all cases we just reset the chip, and any retransmission
    523  * will be handled by higher level protocol timeouts.
    524  */
    525 static void
    526 snwatchdog(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(struct sn_softc *sc, struct mbuf *m0, int mtd_next)
    552 {
    553 	struct mtd *mtdp;
    554 	struct mbuf *m;
    555 	u_char *buff;
    556 	void *txp;
    557 	u_int len = 0;
    558 	u_int totlen = 0;
    559 
    560 #ifdef whyonearthwouldyoudothis
    561 	if (NIC_GET(sc, SNR_CR) & CR_TXP)
    562 		return (0);
    563 #endif
    564 
    565 	/* grab the replacement mtd */
    566 	mtdp = &sc->mtda[sc->mtd_free];
    567 
    568 	buff = mtdp->mtd_buf;
    569 
    570 	/* this packet goes to mtdnext fill in the TDA */
    571 	mtdp->mtd_mbuf = m0;
    572 	txp = mtdp->mtd_txp;
    573 
    574 	/* Write to the config word. Every (NTDA/2)+1 packets we set an intr */
    575 	if (sc->mtd_pint == 0) {
    576 		sc->mtd_pint = NTDA/2;
    577 		SWO(sc->bitmode, txp, TXP_CONFIG, TCR_PINT);
    578 	} else {
    579 		sc->mtd_pint--;
    580 		SWO(sc->bitmode, txp, TXP_CONFIG, 0);
    581 	}
    582 
    583 	for (m = m0; m; m = m->m_next) {
    584 		u_char *data = mtod(m, u_char *);
    585 		len = m->m_len;
    586 		totlen += len;
    587 		memcpy(buff, data, len);
    588 		buff += len;
    589 	}
    590 	if (totlen >= TXBSIZE) {
    591 		panic("%s: sonicput: packet overflow", sc->sc_dev.dv_xname);
    592 	}
    593 
    594 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRLO,
    595 	    LOWER(mtdp->mtd_vbuf));
    596 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FPTRHI,
    597 	    UPPER(mtdp->mtd_vbuf));
    598 
    599 	if (totlen < ETHERMIN + ETHER_HDR_LEN) {
    600 		int pad = ETHERMIN + ETHER_HDR_LEN - totlen;
    601 		memset(mtdp->mtd_buf + totlen, 0, pad);
    602 		totlen = ETHERMIN + ETHER_HDR_LEN;
    603 	}
    604 
    605 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (0 * TXP_FRAGSIZE) + TXP_FSIZE,
    606 	    totlen);
    607 	SWO(sc->bitmode, txp, TXP_FRAGCNT, 1);
    608 	SWO(sc->bitmode, txp, TXP_PKTSIZE, totlen);
    609 
    610 	/* link onto the next mtd that will be used */
    611 	SWO(sc->bitmode, txp, TXP_FRAGOFF + (1 * TXP_FRAGSIZE) + TXP_FPTRLO,
    612 	    LOWER(sc->mtda[mtd_next].mtd_vtxp) | EOL);
    613 
    614 	/*
    615 	 * The previous txp.tlink currently contains a pointer to
    616 	 * our txp | EOL. Want to clear the EOL, so write our
    617 	 * pointer to the previous txp.
    618 	 */
    619 	SWO(sc->bitmode, sc->mtda[sc->mtd_prev].mtd_txp, sc->mtd_tlinko,
    620 	    LOWER(mtdp->mtd_vtxp));
    621 
    622 	/* make sure chip is running */
    623 	wbflush();
    624 	NIC_PUT(sc, SNR_CR, CR_TXP);
    625 	wbflush();
    626 	sc->sc_if.if_timer = 5;	/* 5 seconds to watch for failing to transmit */
    627 
    628 	return (totlen);
    629 }
    630 
    631 /*
    632  * These are called from sonicioctl() when /etc/ifconfig is run to set
    633  * the address or switch the i/f on.
    634  */
    635 /*
    636  * CAM support
    637  */
    638 static void
    639 caminitialise(struct sn_softc *sc)
    640 {
    641 	void *p_cda = sc->p_cda;
    642 	int i;
    643 	int bitmode = sc->bitmode;
    644 	int camoffset;
    645 
    646 	for (i = 0; i < MAXCAM; i++) {
    647 		camoffset = i * CDA_CAMDESC;
    648 		SWO(bitmode, p_cda, (camoffset + CDA_CAMEP), i);
    649 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP2), 0);
    650 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP1), 0);
    651 		SWO(bitmode, p_cda, (camoffset + CDA_CAMAP0), 0);
    652 	}
    653 	SWO(bitmode, p_cda, CDA_ENABLE, 0);
    654 }
    655 
    656 static void
    657 camentry(struct sn_softc *sc, int entry, u_char *ea)
    658 {
    659 	void *p_cda = sc->p_cda;
    660 	int bitmode = sc->bitmode;
    661 	int camoffset = entry * CDA_CAMDESC;
    662 
    663 	SWO(bitmode, p_cda, camoffset + CDA_CAMEP, entry);
    664 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP2, (ea[5] << 8) | ea[4]);
    665 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP1, (ea[3] << 8) | ea[2]);
    666 	SWO(bitmode, p_cda, camoffset + CDA_CAMAP0, (ea[1] << 8) | ea[0]);
    667 	SWO(bitmode, p_cda, CDA_ENABLE,
    668 	    (SRO(bitmode, p_cda, CDA_ENABLE) | (1 << entry)));
    669 }
    670 
    671 static void
    672 camprogram(struct sn_softc *sc)
    673 {
    674 	struct ether_multistep step;
    675 	struct ether_multi *enm;
    676 	struct ifnet *ifp;
    677 	int timeout;
    678 	int mcount = 0;
    679 
    680 	caminitialise(sc);
    681 
    682 	ifp = &sc->sc_if;
    683 
    684 	/* Always load our own address first. */
    685 	camentry (sc, mcount, LLADDR(ifp->if_sadl));
    686 	mcount++;
    687 
    688 	/* Assume we won't need allmulti bit. */
    689 	ifp->if_flags &= ~IFF_ALLMULTI;
    690 
    691 	/* Loop through multicast addresses */
    692 	ETHER_FIRST_MULTI(step, &sc->sc_ethercom, enm);
    693 	while (enm != NULL) {
    694 		if (mcount == MAXCAM) {
    695 			 ifp->if_flags |= IFF_ALLMULTI;
    696 			 break;
    697 		}
    698 
    699 		if (bcmp(enm->enm_addrlo, enm->enm_addrhi,
    700 		    sizeof(enm->enm_addrlo)) != 0) {
    701 			/*
    702 			 * SONIC's CAM is programmed with specific
    703 			 * addresses. It has no way to specify a range.
    704 			 * (Well, thats not exactly true. If the
    705 			 * range is small one could program each addr
    706 			 * within the range as a separate CAM entry)
    707 			 */
    708 			ifp->if_flags |= IFF_ALLMULTI;
    709 			break;
    710 		}
    711 
    712 		/* program the CAM with the specified entry */
    713 		camentry(sc, mcount, enm->enm_addrlo);
    714 		mcount++;
    715 
    716 		ETHER_NEXT_MULTI(step, enm);
    717 	}
    718 
    719 	NIC_PUT(sc, SNR_CDP, LOWER(sc->v_cda));
    720 	NIC_PUT(sc, SNR_CDC, MAXCAM);
    721 	NIC_PUT(sc, SNR_CR, CR_LCAM);
    722 	wbflush();
    723 
    724 	timeout = 10000;
    725 	while ((NIC_GET(sc, SNR_CR) & CR_LCAM) && timeout--)
    726 		continue;
    727 	if (timeout == 0) {
    728 		/* XXX */
    729 		panic("%s: CAM initialisation failed", sc->sc_dev.dv_xname);
    730 	}
    731 	timeout = 10000;
    732 	while (((NIC_GET(sc, SNR_ISR) & ISR_LCD) == 0) && timeout--)
    733 		continue;
    734 
    735 	if (NIC_GET(sc, SNR_ISR) & ISR_LCD)
    736 		NIC_PUT(sc, SNR_ISR, ISR_LCD);
    737 	else
    738 		printf("%s: CAM initialisation without interrupt\n",
    739 		    sc->sc_dev.dv_xname);
    740 }
    741 
    742 #ifdef SNDEBUG
    743 static void
    744 camdump(struct sn_softc *sc)
    745 {
    746 	int i;
    747 
    748 	printf("CAM entries:\n");
    749 	NIC_PUT(sc, SNR_CR, CR_RST);
    750 	wbflush();
    751 
    752 	for (i = 0; i < 16; i++) {
    753 		ushort  ap2, ap1, ap0;
    754 		NIC_PUT(sc, SNR_CEP, i);
    755 		wbflush();
    756 		ap2 = NIC_GET(sc, SNR_CAP2);
    757 		ap1 = NIC_GET(sc, SNR_CAP1);
    758 		ap0 = NIC_GET(sc, SNR_CAP0);
    759 		printf("%d: ap2=0x%x ap1=0x%x ap0=0x%x\n", i, ap2, ap1, ap0);
    760 	}
    761 	printf("CAM enable 0x%x\n", NIC_GET(sc, SNR_CEP));
    762 
    763 	NIC_PUT(sc, SNR_CR, 0);
    764 	wbflush();
    765 }
    766 #endif
    767 
    768 static void
    769 initialise_tda(struct sn_softc *sc)
    770 {
    771 	struct mtd *mtd;
    772 	int i;
    773 
    774 	for (i = 0; i < NTDA; i++) {
    775 		mtd = &sc->mtda[i];
    776 		mtd->mtd_mbuf = 0;
    777 	}
    778 
    779 	sc->mtd_hw = 0;
    780 	sc->mtd_prev = NTDA - 1;
    781 	sc->mtd_free = 0;
    782 	sc->mtd_tlinko = TXP_FRAGOFF + 1*TXP_FRAGSIZE + TXP_FPTRLO;
    783 	sc->mtd_pint = NTDA/2;
    784 
    785 	NIC_PUT(sc, SNR_UTDA, UPPER(sc->mtda[0].mtd_vtxp));
    786 	NIC_PUT(sc, SNR_CTDA, LOWER(sc->mtda[0].mtd_vtxp));
    787 }
    788 
    789 static void
    790 initialise_rda(struct sn_softc *sc)
    791 {
    792 	int bitmode = sc->bitmode;
    793 	int i;
    794 	caddr_t p_rda = 0;
    795 	u_int32_t v_rda = 0;
    796 
    797 	/* link the RDA's together into a circular list */
    798 	for (i = 0; i < (sc->sc_nrda - 1); i++) {
    799 		p_rda = sc->p_rda + (i * RXPKT_SIZE(sc));
    800 		v_rda = sc->v_rda + ((i+1) * RXPKT_SIZE(sc));
    801 		SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(v_rda));
    802 		SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    803 	}
    804 	p_rda = sc->p_rda + ((sc->sc_nrda - 1) * RXPKT_SIZE(sc));
    805 	SWO(bitmode, p_rda, RXPKT_RLINK, LOWER(sc->v_rda) | EOL);
    806 	SWO(bitmode, p_rda, RXPKT_INUSE, 1);
    807 
    808 	/* mark end of receive descriptor list */
    809 	sc->sc_rdamark = sc->sc_nrda - 1;
    810 
    811 	sc->sc_rxmark = 0;
    812 
    813 	NIC_PUT(sc, SNR_URDA, UPPER(sc->v_rda));
    814 	NIC_PUT(sc, SNR_CRDA, LOWER(sc->v_rda));
    815 	wbflush();
    816 }
    817 
    818 static void
    819 initialise_rra(struct sn_softc *sc)
    820 {
    821 	int i;
    822 	u_int v;
    823 	int bitmode = sc->bitmode;
    824 
    825 	if (bitmode)
    826 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 2);
    827 	else
    828 		NIC_PUT(sc, SNR_EOBC, RBASIZE(sc) / 2 - 1);
    829 
    830 	NIC_PUT(sc, SNR_URRA, UPPER(sc->v_rra[0]));
    831 	NIC_PUT(sc, SNR_RSA, LOWER(sc->v_rra[0]));
    832 	/* rea must point just past the end of the rra space */
    833 	NIC_PUT(sc, SNR_REA, LOWER(sc->v_rea));
    834 	NIC_PUT(sc, SNR_RRP, LOWER(sc->v_rra[0]));
    835 	NIC_PUT(sc, SNR_RSC, 0);
    836 
    837 	/* fill up SOME of the rra with buffers */
    838 	for (i = 0; i < NRBA; i++) {
    839 		v = SONIC_GETDMA(sc->rbuf[i]);
    840 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRHI, UPPER(v));
    841 		SWO(bitmode, sc->p_rra[i], RXRSRC_PTRLO, LOWER(v));
    842 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCHI, UPPER(PAGE_SIZE/2));
    843 		SWO(bitmode, sc->p_rra[i], RXRSRC_WCLO, LOWER(PAGE_SIZE/2));
    844 	}
    845 	sc->sc_rramark = NRBA;
    846 	NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[sc->sc_rramark]));
    847 	wbflush();
    848 }
    849 
    850 void
    851 snintr(void *arg)
    852 {
    853 	struct sn_softc *sc = (struct sn_softc *)arg;
    854 	int isr;
    855 
    856 	while ((isr = (NIC_GET(sc, SNR_ISR) & ISR_ALL)) != 0) {
    857 		/* scrub the interrupts that we are going to service */
    858 		NIC_PUT(sc, SNR_ISR, isr);
    859 		wbflush();
    860 
    861 		if (isr & (ISR_BR | ISR_LCD | ISR_TC))
    862 			printf("%s: unexpected interrupt status 0x%x\n",
    863 			    sc->sc_dev.dv_xname, isr);
    864 
    865 		if (isr & (ISR_TXDN | ISR_TXER | ISR_PINT))
    866 			sonictxint(sc);
    867 
    868 		if (isr & ISR_PKTRX)
    869 			sonicrxint(sc);
    870 
    871 		if (isr & (ISR_HBL | ISR_RDE | ISR_RBE | ISR_RBAE | ISR_RFO)) {
    872 			if (isr & ISR_HBL)
    873 				/*
    874 				 * The repeater is not providing a heartbeat.
    875 				 * In itself this isn't harmful, lots of the
    876 				 * cheap repeater hubs don't supply a heartbeat.
    877 				 * So ignore the lack of heartbeat. Its only
    878 				 * if we can't detect a carrier that we have a
    879 				 * problem.
    880 				 */
    881 				;
    882 			if (isr & ISR_RDE)
    883 				printf("%s: receive descriptors exhausted\n",
    884 				    sc->sc_dev.dv_xname);
    885 			if (isr & ISR_RBE)
    886 				printf("%s: receive buffers exhausted\n",
    887 				    sc->sc_dev.dv_xname);
    888 			if (isr & ISR_RBAE)
    889 				printf("%s: receive buffer area exhausted\n",
    890 				    sc->sc_dev.dv_xname);
    891 			if (isr & ISR_RFO)
    892 				printf("%s: receive FIFO overrun\n",
    893 				    sc->sc_dev.dv_xname);
    894 		}
    895 		if (isr & (ISR_CRC | ISR_FAE | ISR_MP)) {
    896 #ifdef notdef
    897 			if (isr & ISR_CRC)
    898 				sc->sc_crctally++;
    899 			if (isr & ISR_FAE)
    900 				sc->sc_faetally++;
    901 			if (isr & ISR_MP)
    902 				sc->sc_mptally++;
    903 #endif
    904 		}
    905 		snstart(&sc->sc_if);
    906 	}
    907 	return;
    908 }
    909 
    910 /*
    911  * Transmit interrupt routine
    912  */
    913 static void
    914 sonictxint(struct sn_softc *sc)
    915 {
    916 	struct mtd *mtd;
    917 	struct ifnet *ifp = &sc->sc_if;
    918 	void *txp;
    919 	int mtd_hw;
    920 	unsigned short txp_status;
    921 
    922 	mtd_hw = sc->mtd_hw;
    923 
    924 	if (mtd_hw == sc->mtd_free)
    925 		return;
    926 
    927 	while (mtd_hw != sc->mtd_free) {
    928 		mtd = &sc->mtda[mtd_hw];
    929 
    930 		txp = mtd->mtd_txp;
    931 
    932 		if (SRO(sc->bitmode, txp, TXP_STATUS) == 0) {
    933 			break; /* it hasn't really gone yet */
    934 		}
    935 
    936 #ifdef SNDEBUG
    937 		{
    938 			struct ether_header *eh;
    939 
    940 			eh = (struct ether_header *) mtd->mtd_buf;
    941 			printf("%s: xmit status=0x%x len=%d type=0x%x from %s",
    942 			    sc->sc_dev.dv_xname,
    943 			    SRO(sc->bitmode, txp, TXP_STATUS),
    944 			    SRO(sc->bitmode, txp, TXP_PKTSIZE),
    945 			    htons(eh->ether_type),
    946 			    ether_sprintf(eh->ether_shost));
    947 			printf(" (to %s)\n", ether_sprintf(eh->ether_dhost));
    948 		}
    949 #endif /* SNDEBUG */
    950 
    951 		ifp->if_flags &= ~IFF_OACTIVE;
    952 
    953 		if (mtd->mtd_mbuf != 0) {
    954 			m_freem(mtd->mtd_mbuf);
    955 			mtd->mtd_mbuf = 0;
    956 		}
    957 		if (++mtd_hw == NTDA) mtd_hw = 0;
    958 
    959 		txp_status = SRO(sc->bitmode, txp, TXP_STATUS);
    960 
    961 		ifp->if_collisions += (txp_status & TCR_EXC) ? 16 :
    962 			((txp_status & TCR_NC) >> 12);
    963 
    964 		if ((txp_status & TCR_PTX) == 0) {
    965 			ifp->if_oerrors++;
    966 			printf("%s: Tx packet status=0x%x\n",
    967 			    sc->sc_dev.dv_xname, txp_status);
    968 
    969 			/* XXX - DG This looks bogus */
    970 			if (mtd_hw != sc->mtd_free) {
    971 				printf("resubmitting remaining packets\n");
    972 				mtd = &sc->mtda[mtd_hw];
    973 				NIC_PUT(sc, SNR_CTDA, LOWER(mtd->mtd_vtxp));
    974 				NIC_PUT(sc, SNR_CR, CR_TXP);
    975 				wbflush();
    976 				break;
    977 			}
    978 		}
    979 	}
    980 
    981 	sc->mtd_hw = mtd_hw;
    982 	return;
    983 }
    984 
    985 /*
    986  * Receive interrupt routine
    987  */
    988 static void
    989 sonicrxint(struct sn_softc *sc)
    990 {
    991 	caddr_t	rda;
    992 	int orra;
    993 	int len;
    994 	int rramark;
    995 	int rdamark;
    996 	int bitmode = sc->bitmode;
    997 	u_int16_t rxpkt_ptr;
    998 
    999 	rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1000 
   1001 	while (SRO(bitmode, rda, RXPKT_INUSE) == 0) {
   1002 		u_int status = SRO(bitmode, rda, RXPKT_STATUS);
   1003 
   1004 		orra = RBASEQ(SRO(bitmode, rda, RXPKT_SEQNO)) & RRAMASK;
   1005 		rxpkt_ptr = SRO(bitmode, rda, RXPKT_PTRLO);
   1006 		len = SRO(bitmode, rda, RXPKT_BYTEC) - FCSSIZE;
   1007 		if (status & RCR_PRX) {
   1008 			caddr_t pkt = sc->rbuf[orra & RBAMASK] +
   1009 			    m68k_page_offset(rxpkt_ptr);
   1010 			if (sonic_read(sc, pkt, len))
   1011 				sc->sc_if.if_ipackets++;
   1012 			else
   1013 				sc->sc_if.if_ierrors++;
   1014 		} else
   1015 			sc->sc_if.if_ierrors++;
   1016 
   1017 		/*
   1018 		 * give receive buffer area back to chip.
   1019 		 *
   1020 		 * If this was the last packet in the RRA, give the RRA to
   1021 		 * the chip again.
   1022 		 * If sonic read didnt copy it out then we would have to
   1023 		 * wait !!
   1024 		 * (dont bother add it back in again straight away)
   1025 		 *
   1026 		 * Really, we're doing p_rra[rramark] = p_rra[orra] but
   1027 		 * we have to use the macros because SONIC might be in
   1028 		 * 16 or 32 bit mode.
   1029 		 */
   1030 		if (status & RCR_LPKT) {
   1031 			void *tmp1, *tmp2;
   1032 
   1033 			rramark = sc->sc_rramark;
   1034 			tmp1 = sc->p_rra[rramark];
   1035 			tmp2 = sc->p_rra[orra];
   1036 			SWO(bitmode, tmp1, RXRSRC_PTRLO,
   1037 				SRO(bitmode, tmp2, RXRSRC_PTRLO));
   1038 			SWO(bitmode, tmp1, RXRSRC_PTRHI,
   1039 				SRO(bitmode, tmp2, RXRSRC_PTRHI));
   1040 			SWO(bitmode, tmp1, RXRSRC_WCLO,
   1041 				SRO(bitmode, tmp2, RXRSRC_WCLO));
   1042 			SWO(bitmode, tmp1, RXRSRC_WCHI,
   1043 				SRO(bitmode, tmp2, RXRSRC_WCHI));
   1044 
   1045 			/* zap old rra for fun */
   1046 			SWO(bitmode, tmp2, RXRSRC_WCHI, 0);
   1047 			SWO(bitmode, tmp2, RXRSRC_WCLO, 0);
   1048 
   1049 			sc->sc_rramark = (++rramark) & RRAMASK;
   1050 			NIC_PUT(sc, SNR_RWP, LOWER(sc->v_rra[rramark]));
   1051 			wbflush();
   1052 		}
   1053 
   1054 		/*
   1055 		 * give receive descriptor back to chip simple
   1056 		 * list is circular
   1057 		 */
   1058 		rdamark = sc->sc_rdamark;
   1059 		SWO(bitmode, rda, RXPKT_INUSE, 1);
   1060 		SWO(bitmode, rda, RXPKT_RLINK,
   1061 			SRO(bitmode, rda, RXPKT_RLINK) | EOL);
   1062 		SWO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))), RXPKT_RLINK,
   1063 			SRO(bitmode, (sc->p_rda + (rdamark * RXPKT_SIZE(sc))),
   1064 			RXPKT_RLINK) & ~EOL);
   1065 		sc->sc_rdamark = sc->sc_rxmark;
   1066 
   1067 		if (++sc->sc_rxmark >= sc->sc_nrda)
   1068 			sc->sc_rxmark = 0;
   1069 		rda = sc->p_rda + (sc->sc_rxmark * RXPKT_SIZE(sc));
   1070 	}
   1071 }
   1072 
   1073 /*
   1074  * sonic_read -- pull packet off interface and forward to
   1075  * appropriate protocol handler
   1076  */
   1077 static __inline__ int
   1078 sonic_read(struct sn_softc *sc, caddr_t pkt, int len)
   1079 {
   1080 	struct ifnet *ifp = &sc->sc_if;
   1081 	struct mbuf *m;
   1082 
   1083 #ifdef SNDEBUG
   1084 	{
   1085 		printf("%s: rcvd 0x%p len=%d type=0x%x from %s",
   1086 		    sc->sc_dev.dv_xname, et, len, htons(et->ether_type),
   1087 		    ether_sprintf(et->ether_shost));
   1088 		printf(" (to %s)\n", ether_sprintf(et->ether_dhost));
   1089 	}
   1090 #endif /* SNDEBUG */
   1091 
   1092 	if (len < (ETHER_MIN_LEN - ETHER_CRC_LEN) ||
   1093 	    len > (ETHER_MAX_LEN - ETHER_CRC_LEN)) {
   1094 		printf("%s: invalid packet length %d bytes\n",
   1095 		    sc->sc_dev.dv_xname, len);
   1096 		return (0);
   1097 	}
   1098 
   1099 	m = sonic_get(sc, pkt, len);
   1100 	if (m == NULL)
   1101 		return (0);
   1102 #if NBPFILTER > 0
   1103 	/* Pass this up to any BPF listeners. */
   1104 	if (ifp->if_bpf)
   1105 		bpf_mtap(ifp->if_bpf, m);
   1106 #endif
   1107 	(*ifp->if_input)(ifp, m);
   1108 	return (1);
   1109 }
   1110 
   1111 /*
   1112  * munge the received packet into an mbuf chain
   1113  */
   1114 static __inline__ struct mbuf *
   1115 sonic_get(struct sn_softc *sc, caddr_t pkt, int datalen)
   1116 {
   1117 	struct mbuf *m, *top, **mp;
   1118 	int len;
   1119 
   1120 	MGETHDR(m, M_DONTWAIT, MT_DATA);
   1121 	if (m == 0)
   1122 		return (0);
   1123 	m->m_pkthdr.rcvif = &sc->sc_if;
   1124 	m->m_pkthdr.len = datalen;
   1125 	len = MHLEN;
   1126 	top = 0;
   1127 	mp = &top;
   1128 
   1129 	while (datalen > 0) {
   1130 		if (top) {
   1131 			MGET(m, M_DONTWAIT, MT_DATA);
   1132 			if (m == 0) {
   1133 				m_freem(top);
   1134 				return (0);
   1135 			}
   1136 			len = MLEN;
   1137 		}
   1138 		if (datalen >= MINCLSIZE) {
   1139 			MCLGET(m, M_DONTWAIT);
   1140 			if ((m->m_flags & M_EXT) == 0) {
   1141 				if (top) m_freem(top);
   1142 				return (0);
   1143 			}
   1144 			len = MCLBYTES;
   1145 		}
   1146 
   1147 		if (mp == &top) {
   1148 			caddr_t newdata = (caddr_t)
   1149 			    ALIGN(m->m_data + sizeof(struct ether_header)) -
   1150 			    sizeof(struct ether_header);
   1151 			len -= newdata - m->m_data;
   1152 			m->m_data = newdata;
   1153 		}
   1154 
   1155 		m->m_len = len = min(datalen, len);
   1156 
   1157 		memcpy(mtod(m, caddr_t), pkt, len);
   1158 		pkt += len;
   1159 		datalen -= len;
   1160 		*mp = m;
   1161 		mp = &m->m_next;
   1162 	}
   1163 
   1164 	return (top);
   1165 }
   1166 
   1167 static u_char bbr4[] = {0,8,4,12,2,10,6,14,1,9,5,13,3,11,7,15};
   1168 #define bbr(v)	((bbr4[(v)&0xf] << 4) | bbr4[((v)>>4) & 0xf])
   1169 
   1170 void
   1171 sn_get_enaddr(bus_space_tag_t t, bus_space_handle_t h, bus_size_t o,
   1172     u_char *dst)
   1173 {
   1174 	int i, do_bbr;
   1175 	u_char b;
   1176 
   1177 	/*
   1178 	 * For reasons known only to Apple, MAC addresses in the ethernet
   1179 	 * PROM are stored in Token Ring (IEEE 802.5) format, that is
   1180 	 * with all of the bits in each byte reversed (canonical bit format).
   1181 	 * When the address is read out it must be reversed to ethernet format
   1182 	 * before use.
   1183 	 *
   1184 	 * Apple has been assigned OUI's 08:00:07 and 00:a0:40. All onboard
   1185 	 * ethernet addresses on 68K machines should be in one of these
   1186 	 * two ranges.
   1187 	 *
   1188 	 * Here is where it gets complicated.
   1189 	 *
   1190 	 * The PMac 7200, 7500, 8500, and 9500 accidentally had the PROM
   1191 	 * written in standard ethernet format. The MacOS accounted for this
   1192 	 * in these systems, and did not reverse the bytes. Some other
   1193 	 * networking utilities were not so forgiving, and got confused.
   1194 	 * "Some" of Apple's Nubus ethernet cards also had their bits
   1195 	 * burned in ethernet format.
   1196 	 *
   1197 	 * Apple petitioned the IEEE and was granted the 00:05:02 (bit reversal
   1198 	 * of 00:a0:40) as well. As of OpenTransport 1.1.1, Apple removed
   1199 	 * their workaround and now reverses the bits regardless of
   1200 	 * what kind of machine it is. So PMac systems and the affected
   1201 	 * Nubus cards now use 00:05:02, instead of the 00:a0:40 for which they
   1202 	 * were intended.
   1203 	 *
   1204 	 * See Apple Techinfo article TECHINFO-0020552, "OpenTransport 1.1.1
   1205 	 * and MacOS System 7.5.3 FAQ (10/96)" for more details.
   1206 	 */
   1207 	do_bbr = 0;
   1208 	b = bus_space_read_1(t, h, o);
   1209 	if (b == 0x10)
   1210 		do_bbr = 1;
   1211 	dst[0] = (do_bbr) ? bbr(b) : b;
   1212 
   1213 	for (i = 1 ; i < ETHER_ADDR_LEN ; i++) {
   1214 		b = bus_space_read_1(t, h, o+i);
   1215 		dst[i] = (do_bbr) ? bbr(b) : b;
   1216 	}
   1217 }
   1218