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if_el.c revision 1.14 
      1 /*	$NetBSD: if_el.c,v 1.14 1994/10/27 04:17:28 cgd Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1994, Matthew E. Kimmel.  Permission is hereby granted
      5  * to use, copy, modify and distribute this software provided that both
      6  * the copyright notice and this permission notice appear in all copies
      7  * of the software, derivative works or modified versions, and any
      8  * portions thereof.
      9  */
     10 
     11 /*
     12  * 3COM Etherlink 3C501 device driver
     13  */
     14 
     15 /*
     16  * Bugs/possible improvements:
     17  *	- Does not currently support DMA
     18  *	- Does not currently support multicasts
     19  */
     20 
     21 #include "bpfilter.h"
     22 
     23 #include <sys/param.h>
     24 #include <sys/errno.h>
     25 #include <sys/ioctl.h>
     26 #include <sys/mbuf.h>
     27 #include <sys/socket.h>
     28 #include <sys/syslog.h>
     29 #include <sys/device.h>
     30 
     31 #include <net/if.h>
     32 #include <net/if_dl.h>
     33 #include <net/if_types.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_ether.h>
     41 #endif
     42 
     43 #ifdef NS
     44 #include <netns/ns.h>
     45 #include <netns/ns_if.h>
     46 #endif
     47 
     48 #if NBPFILTER > 0
     49 #include <net/bpf.h>
     50 #include <net/bpfdesc.h>
     51 #endif
     52 
     53 #include <machine/cpu.h>
     54 #include <machine/pio.h>
     55 
     56 #include <i386/isa/isavar.h>
     57 #include <i386/isa/icu.h>
     58 #include <i386/isa/if_elreg.h>
     59 
     60 #define ETHER_MIN_LEN	64
     61 #define ETHER_MAX_LEN	1518
     62 #define	ETHER_ADDR_LEN	6
     63 
     64 /* for debugging convenience */
     65 #ifdef EL_DEBUG
     66 #define dprintf(x) printf x
     67 #else
     68 #define dprintf(x)
     69 #endif
     70 
     71 /*
     72  * per-line info and status
     73  */
     74 struct el_softc {
     75 	struct device sc_dev;
     76 	struct intrhand sc_ih;
     77 
     78 	struct arpcom sc_arpcom;	/* ethernet common */
     79 	u_short sc_iobase;		/* base I/O addr */
     80 	char sc_pktbuf[EL_BUFSIZ]; 	/* frame buffer */
     81 };
     82 
     83 /*
     84  * prototypes
     85  */
     86 int elintr __P((struct el_softc *));
     87 static int el_init __P((struct el_softc *));
     88 static int el_ioctl __P((struct ifnet *, int, caddr_t));
     89 static int el_start __P((struct ifnet *));
     90 static int el_watchdog __P((int));
     91 static void el_reset __P((struct el_softc *));
     92 static void el_stop __P((struct el_softc *));
     93 static int el_xmit __P((struct el_softc *, int));
     94 static inline void elread __P((struct el_softc *, caddr_t, int));
     95 static struct mbuf *elget __P((caddr_t, int, struct ifnet *));
     96 static inline void el_hardreset __P((struct el_softc *));
     97 
     98 int elprobe();
     99 void elattach();
    100 
    101 /* isa_driver structure for autoconf */
    102 struct cfdriver elcd = {
    103 	NULL, "el", elprobe, elattach, DV_IFNET, sizeof(struct el_softc)
    104 };
    105 
    106 /*
    107  * Probe routine.
    108  *
    109  * See if the card is there and at the right place.
    110  * (XXX - cgd -- needs help)
    111  */
    112 int
    113 elprobe(parent, self, aux)
    114 	struct device *parent, *self;
    115 	void *aux;
    116 {
    117 	struct el_softc *sc = (void *)self;
    118 	struct isa_attach_args *ia = aux;
    119 	u_short iobase = ia->ia_iobase;
    120 	u_char station_addr[ETHER_ADDR_LEN];
    121 	int i;
    122 
    123 	/* First check the base. */
    124 	if (iobase < 0x280 || iobase > 0x3f0)
    125 		return 0;
    126 
    127 	/* Grab some info for our structure. */
    128 	sc->sc_iobase = iobase;
    129 
    130 	/*
    131 	 * Now attempt to grab the station address from the PROM and see if it
    132 	 * contains the 3com vendor code.
    133 	 */
    134 	dprintf(("Probing 3c501 at 0x%x...\n", iobase));
    135 
    136 	/* Reset the board. */
    137 	dprintf(("Resetting board...\n"));
    138 	outb(iobase+EL_AC, EL_AC_RESET);
    139 	delay(5);
    140 	outb(iobase+EL_AC, 0);
    141 
    142 	/* Now read the address. */
    143 	dprintf(("Reading station address...\n"));
    144 	for (i = 0; i < ETHER_ADDR_LEN; i++) {
    145 		outb(iobase+EL_GPBL, i);
    146 		station_addr[i] = inb(iobase+EL_EAW);
    147 	}
    148 	dprintf(("Address is %s\n", ether_sprintf(station_addr)));
    149 
    150 	/*
    151 	 * If the vendor code is ok, return a 1.  We'll assume that whoever
    152 	 * configured this system is right about the IRQ.
    153 	 */
    154 	if (station_addr[0] != 0x02 || station_addr[1] != 0x60 ||
    155 	    station_addr[2] != 0x8c) {
    156 		dprintf(("Bad vendor code.\n"));
    157 		return 0;
    158 	}
    159 
    160 	dprintf(("Vendor code ok.\n"));
    161 	/* Copy the station address into the arpcom structure. */
    162 	bcopy(station_addr, sc->sc_arpcom.ac_enaddr, ETHER_ADDR_LEN);
    163 
    164 	ia->ia_iosize = 4;	/* XXX */
    165 	ia->ia_msize = 0;
    166 	return 1;
    167 }
    168 
    169 /*
    170  * Attach the interface to the kernel data structures.  By the time this is
    171  * called, we know that the card exists at the given I/O address.  We still
    172  * assume that the IRQ given is correct.
    173  */
    174 void
    175 elattach(parent, self, aux)
    176 	struct device *parent, *self;
    177 	void *aux;
    178 {
    179 	struct el_softc *sc = (void *)self;
    180 	struct isa_attach_args *ia = aux;
    181 	struct ifnet *ifp = &sc->sc_arpcom.ac_if;
    182 
    183 	dprintf(("Attaching %s...\n", sc->sc_dev.dv_xname));
    184 
    185 	/* Stop the board. */
    186 	el_stop(sc);
    187 
    188 	/* Initialize ifnet structure. */
    189 	ifp->if_unit = sc->sc_dev.dv_unit;
    190 	ifp->if_name = elcd.cd_name;
    191 	ifp->if_output = ether_output;
    192 	ifp->if_start = el_start;
    193 	ifp->if_ioctl = el_ioctl;
    194 	ifp->if_watchdog = el_watchdog;
    195 	ifp->if_flags = IFF_BROADCAST | IFF_SIMPLEX | IFF_NOTRAILERS;
    196 
    197 	/* Now we can attach the interface. */
    198 	dprintf(("Attaching interface...\n"));
    199 	if_attach(ifp);
    200 	ether_ifattach(ifp);
    201 
    202 	/* Print out some information for the user. */
    203 	printf("%s: address %s\n", sc->sc_dev.dv_xname,
    204 	    ether_sprintf(sc->sc_arpcom.ac_enaddr));
    205 
    206 	/* Finally, attach to bpf filter if it is present. */
    207 #if NBPFILTER > 0
    208 	dprintf(("Attaching to BPF...\n"));
    209 	bpfattach(&ifp->if_bpf, ifp, DLT_EN10MB, sizeof(struct ether_header));
    210 #endif
    211 
    212 	sc->sc_ih.ih_fun = elintr;
    213 	sc->sc_ih.ih_arg = sc;
    214 	sc->sc_ih.ih_level = IPL_NET;
    215 	intr_establish(ia->ia_irq, &sc->sc_ih);
    216 
    217 	dprintf(("elattach() finished.\n"));
    218 }
    219 
    220 /*
    221  * Reset interface.
    222  */
    223 static void
    224 el_reset(sc)
    225 	struct el_softc *sc;
    226 {
    227 	int s;
    228 
    229 	dprintf(("elreset()\n"));
    230 	s = splimp();
    231 	el_stop(sc);
    232 	el_init(sc);
    233 	splx(s);
    234 }
    235 
    236 /*
    237  * Stop interface.
    238  */
    239 static void
    240 el_stop(sc)
    241 	struct el_softc *sc;
    242 {
    243 
    244 	outb(sc->sc_iobase+EL_AC, 0);
    245 }
    246 
    247 /*
    248  * Do a hardware reset of the board, and upload the ethernet address again in
    249  * case the board forgets.
    250  */
    251 static inline void
    252 el_hardreset(sc)
    253 	struct el_softc *sc;
    254 {
    255 	u_short iobase = sc->sc_iobase;
    256 	int i;
    257 
    258 	outb(iobase+EL_AC, EL_AC_RESET);
    259 	delay(5);
    260 	outb(iobase+EL_AC, 0);
    261 
    262 	for (i = 0; i < ETHER_ADDR_LEN; i++)
    263 		outb(iobase+i, sc->sc_arpcom.ac_enaddr[i]);
    264 }
    265 
    266 /*
    267  * Initialize interface.
    268  */
    269 static int
    270 el_init(sc)
    271 	struct el_softc *sc;
    272 {
    273 	struct ifnet *ifp = &sc->sc_arpcom.ac_if;
    274 	u_short iobase = sc->sc_iobase;
    275 	int s;
    276 
    277 	/* If address not known, do nothing. */
    278 	if (ifp->if_addrlist == 0)
    279 		return;
    280 
    281 	s = splimp();
    282 
    283 	/* First, reset the board. */
    284 	el_hardreset(sc);
    285 
    286 	/* Configure rx. */
    287 	dprintf(("Configuring rx...\n"));
    288 	if (ifp->if_flags & IFF_PROMISC)
    289 		outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_PROMISC);
    290 	else
    291 		outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_ABROAD);
    292 	outb(iobase+EL_RBC, 0);
    293 
    294 	/* Configure TX. */
    295 	dprintf(("Configuring tx...\n"));
    296 	outb(iobase+EL_TXC, 0);
    297 
    298 	/* Start reception. */
    299 	dprintf(("Starting reception...\n"));
    300 	outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    301 
    302 	/* Set flags appropriately. */
    303 	ifp->if_flags |= IFF_RUNNING;
    304 	ifp->if_flags &= ~IFF_OACTIVE;
    305 
    306 	/* And start output. */
    307 	el_start(ifp);
    308 
    309 	splx(s);
    310 }
    311 
    312 /*
    313  * Start output on interface.  Get datagrams from the queue and output them,
    314  * giving the receiver a chance between datagrams.  Call only from splimp or
    315  * interrupt level!
    316  */
    317 static int
    318 el_start(ifp)
    319 	struct ifnet *ifp;
    320 {
    321 	struct el_softc *sc = elcd.cd_devs[ifp->if_unit];
    322 	u_short iobase = sc->sc_iobase;
    323 	struct mbuf *m, *m0;
    324 	int s, i, len, retries, done;
    325 
    326 	dprintf(("el_start()...\n"));
    327 	s = splimp();
    328 
    329 	/* Don't do anything if output is active. */
    330 	if (sc->sc_arpcom.ac_if.if_flags & IFF_OACTIVE)
    331 		return;
    332 	sc->sc_arpcom.ac_if.if_flags |= IFF_OACTIVE;
    333 
    334 	/*
    335 	 * The main loop.  They warned me against endless loops, but would I
    336 	 * listen?  NOOO....
    337 	 */
    338 	for (;;) {
    339 		/* Dequeue the next datagram. */
    340 		IF_DEQUEUE(&sc->sc_arpcom.ac_if.if_snd, m0);
    341 
    342 		/* If there's nothing to send, return. */
    343 		if (!m0) {
    344 			sc->sc_arpcom.ac_if.if_flags &= ~IFF_OACTIVE;
    345 			splx(s);
    346 			return;
    347 		}
    348 
    349 		/* Disable the receiver. */
    350 		outb(iobase+EL_AC, EL_AC_HOST);
    351 		outb(iobase+EL_RBC, 0);
    352 
    353 		/* Copy the datagram to the buffer. */
    354 		len = 0;
    355 		for (m = m0; m; m = m->m_next) {
    356 			if (m->m_len == 0)
    357 				continue;
    358 			bcopy(mtod(m, caddr_t), sc->sc_pktbuf + len, m->m_len);
    359 			len += m->m_len;
    360 		}
    361 		m_freem(m0);
    362 
    363 		len = max(len, ETHER_MIN_LEN);
    364 
    365 		/* Give the packet to the bpf, if any. */
    366 #if NBPFILTER > 0
    367 		if (sc->sc_arpcom.ac_if.if_bpf)
    368 			bpf_tap(sc->sc_arpcom.ac_if.if_bpf, sc->sc_pktbuf, len);
    369 #endif
    370 
    371 		/* Transfer datagram to board. */
    372 		dprintf(("el: xfr pkt length=%d...\n", len));
    373 		i = EL_BUFSIZ - len;
    374 		outb(iobase+EL_GPBL, i);
    375 		outb(iobase+EL_GPBH, i >> 8);
    376 		outsb(iobase+EL_BUF, sc->sc_pktbuf, len);
    377 
    378 		/* Now transmit the datagram. */
    379 		retries = 0;
    380 		done = 0;
    381 		while (!done) {
    382 			if (el_xmit(sc, len)) {
    383 				/* Something went wrong. */
    384 				done = -1;
    385 				break;
    386 			}
    387 			/* Check out status. */
    388 			i = inb(iobase+EL_TXS);
    389 			dprintf(("tx status=0x%x\n", i));
    390 			if ((i & EL_TXS_READY) == 0) {
    391 				dprintf(("el: err txs=%x\n", i));
    392 				sc->sc_arpcom.ac_if.if_oerrors++;
    393 				if (i & (EL_TXS_COLL | EL_TXS_COLL16)) {
    394 					if ((i & EL_TXC_DCOLL16) == 0 &&
    395 					    retries < 15) {
    396 						retries++;
    397 						outb(iobase+EL_AC, EL_AC_HOST);
    398 					}
    399 				} else
    400 					done = 1;
    401 			} else {
    402 				sc->sc_arpcom.ac_if.if_opackets++;
    403 				done = 1;
    404 			}
    405 		}
    406 		if (done == -1)
    407 			/* Packet not transmitted. */
    408 			continue;
    409 
    410 		/*
    411 		 * Now give the card a chance to receive.
    412 		 * Gotta love 3c501s...
    413 		 */
    414 		(void)inb(iobase+EL_AS);
    415 		outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    416 		splx(s);
    417 		/* Interrupt here. */
    418 		s = splimp();
    419 	}
    420 }
    421 
    422 /*
    423  * This function actually attempts to transmit a datagram downloaded to the
    424  * board.  Call at splimp or interrupt, after downloading data!  Returns 0 on
    425  * success, non-0 on failure.
    426  */
    427 static int
    428 el_xmit(sc, len)
    429 	struct el_softc *sc;
    430 	int len;
    431 {
    432 	u_short iobase = sc->sc_iobase;
    433 	int gpl;
    434 	int i;
    435 
    436 	gpl = EL_BUFSIZ - len;
    437 	dprintf(("el: xmit..."));
    438 	outb(iobase+EL_GPBL, gpl);
    439 	outb(iobase+EL_GPBH, gpl >> 8);
    440 	outb(iobase+EL_AC, EL_AC_TXFRX);
    441 	i = 20000;
    442 	while ((inb(iobase+EL_AS) & EL_AS_TXBUSY) && (i > 0))
    443 		i--;
    444 	if (i == 0) {
    445 		dprintf(("tx not ready\n"));
    446 		sc->sc_arpcom.ac_if.if_oerrors++;
    447 		return -1;
    448 	}
    449 	dprintf(("%d cycles.\n", 20000 - i));
    450 	return 0;
    451 }
    452 
    453 /*
    454  * Controller interrupt.
    455  */
    456 int
    457 elintr(sc)
    458 	register struct el_softc *sc;
    459 {
    460 	u_short iobase = sc->sc_iobase;
    461 	int stat, rxstat, len, done;
    462 
    463 	dprintf(("elintr: "));
    464 
    465 	/* Check board status. */
    466 	stat = inb(iobase+EL_AS);
    467 	if (stat & EL_AS_RXBUSY) {
    468 		(void)inb(iobase+EL_RXC);
    469 		outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    470 		return 0;
    471 	}
    472 
    473 	done = 0;
    474 	while (!done) {
    475 		rxstat = inb(iobase+EL_RXS);
    476 		if (rxstat & EL_RXS_STALE) {
    477 			(void)inb(iobase+EL_RXC);
    478 			outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    479 			return 1;
    480 		}
    481 
    482 		/* If there's an overflow, reinit the board. */
    483 		if ((rxstat & EL_RXS_NOFLOW) == 0) {
    484 			dprintf(("overflow.\n"));
    485 			el_hardreset(sc);
    486 			/* Put board back into receive mode. */
    487 			if (sc->sc_arpcom.ac_if.if_flags & IFF_PROMISC)
    488 				outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_PROMISC);
    489 			else
    490 				outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_ABROAD);
    491 			(void)inb(iobase+EL_AS);
    492 			outb(iobase+EL_RBC, 0);
    493 			(void)inb(iobase+EL_RXC);
    494 			outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    495 			return 1;
    496 		}
    497 
    498 		/* Incoming packet. */
    499 		len = inb(iobase+EL_RBL);
    500 		len |= inb(iobase+EL_RBH) << 8;
    501 		dprintf(("receive len=%d rxstat=%x ", len, rxstat));
    502 		outb(iobase+EL_AC, EL_AC_HOST);
    503 
    504 		/*
    505 		 * If packet too short or too long, restore rx mode and return.
    506 		 */
    507 		if (len <= sizeof(struct ether_header) ||
    508 		    len > ETHER_MAX_LEN) {
    509 			if (sc->sc_arpcom.ac_if.if_flags & IFF_PROMISC)
    510 				outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_PROMISC);
    511 			else
    512 				outb(iobase+EL_RXC, EL_RXC_AGF | EL_RXC_DSHORT | EL_RXC_DDRIB | EL_RXC_DOFLOW | EL_RXC_ABROAD);
    513 			(void)inb(iobase+EL_AS);
    514 			outb(iobase+EL_RBC, 0);
    515 			(void)inb(iobase+EL_RXC);
    516 			outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    517 			return 1;
    518 		}
    519 
    520 		sc->sc_arpcom.ac_if.if_ipackets++;
    521 
    522 		/* Copy the data into our buffer. */
    523 		outb(iobase+EL_GPBL, 0);
    524 		outb(iobase+EL_GPBH, 0);
    525 		insb(iobase+EL_BUF, sc->sc_pktbuf, len);
    526 		outb(iobase+EL_RBC, 0);
    527 		outb(iobase+EL_AC, EL_AC_RX);
    528 		dprintf(("%s-->", ether_sprintf(sc->sc_pktbuf+6)));
    529 		dprintf(("%s\n", ether_sprintf(sc->sc_pktbuf)));
    530 
    531 		/* Pass data up to upper levels. */
    532 		elread(sc, (caddr_t)sc->sc_pktbuf, len);
    533 
    534 		/* Is there another packet? */
    535 		stat = inb(iobase+EL_AS);
    536 
    537 		/* If so, do it all again (i.e. don't set done to 1). */
    538 		if ((stat & EL_AS_RXBUSY) == 0)
    539 			dprintf(("<rescan> "));
    540 		else
    541 			done = 1;
    542 	}
    543 
    544 	(void)inb(iobase+EL_RXC);
    545 	outb(iobase+EL_AC, EL_AC_IRQE | EL_AC_RX);
    546 	return 1;
    547 }
    548 
    549 /*
    550  * Pass a packet up to the higher levels.
    551  */
    552 static inline void
    553 elread(sc, buf, len)
    554 	struct el_softc *sc;
    555 	caddr_t buf;
    556 	int len;
    557 {
    558 	register struct ether_header *eh;
    559 	struct mbuf *m;
    560 
    561 	eh = (struct ether_header *)buf;
    562 	len -= sizeof(struct ether_header);
    563 	if (len <= 0)
    564 		return;
    565 
    566 	/* Pull packet off interface. */
    567 	m = elget(buf, len, &sc->sc_arpcom.ac_if);
    568 	if (m == 0)
    569 		return;
    570 
    571 #if NBPFILTER > 0
    572 	/*
    573 	 * Check if there's a BPF listener on this interface.
    574 	 * If so, hand off the raw packet to bpf.
    575 	 */
    576 	if (sc->sc_arpcom.ac_if.if_bpf) {
    577 		bpf_mtap(sc->sc_arpcom.ac_if.if_bpf, m);
    578 
    579 		/*
    580 		 * Note that the interface cannot be in promiscuous mode if
    581 		 * there are no BPF listeners.  And if we are in promiscuous
    582 		 * mode, we have to check if this packet is really ours.
    583 		 */
    584 		if ((sc->sc_arpcom.ac_if.if_flags & IFF_PROMISC) &&
    585 		    (eh->ether_dhost[0] & 1) == 0 && /* !mcast and !bcast */
    586 		    bcmp(eh->ether_dhost, sc->sc_arpcom.ac_enaddr,
    587 			    sizeof(eh->ether_dhost)) != 0) {
    588 			m_freem(m);
    589 			return;
    590 		}
    591 	}
    592 #endif
    593 
    594 	ether_input(&sc->sc_arpcom.ac_if, eh, m);
    595 }
    596 
    597 /*
    598  * Pull read data off a interface.  Len is length of data, with local net
    599  * header stripped.  We copy the data into mbufs.  When full cluster sized
    600  * units are present we copy into clusters.
    601  */
    602 struct mbuf *
    603 elget(buf, totlen, ifp)
    604         caddr_t buf;
    605         int totlen;
    606         struct ifnet *ifp;
    607 {
    608         struct mbuf *top, **mp, *m, *p;
    609         int len;
    610         register caddr_t cp = buf;
    611         char *epkt;
    612 
    613         buf += sizeof(struct ether_header);
    614         cp = buf;
    615         epkt = cp + totlen;
    616 
    617         MGETHDR(m, M_DONTWAIT, MT_DATA);
    618         if (m == 0)
    619                 return 0;
    620         m->m_pkthdr.rcvif = ifp;
    621         m->m_pkthdr.len = totlen;
    622         m->m_len = MHLEN;
    623         top = 0;
    624         mp = &top;
    625 
    626         while (totlen > 0) {
    627                 if (top) {
    628                         MGET(m, M_DONTWAIT, MT_DATA);
    629                         if (m == 0) {
    630                                 m_freem(top);
    631                                 return 0;
    632                         }
    633                         m->m_len = MLEN;
    634                 }
    635                 len = min(totlen, epkt - cp);
    636                 if (len >= MINCLSIZE) {
    637                         MCLGET(m, M_DONTWAIT);
    638                         if (m->m_flags & M_EXT)
    639                                 m->m_len = len = min(len, MCLBYTES);
    640                         else
    641                                 len = m->m_len;
    642                 } else {
    643                         /*
    644                          * Place initial small packet/header at end of mbuf.
    645                          */
    646                         if (len < m->m_len) {
    647                                 if (top == 0 && len + max_linkhdr <= m->m_len)
    648                                         m->m_data += max_linkhdr;
    649                                 m->m_len = len;
    650                         } else
    651                                 len = m->m_len;
    652                 }
    653                 bcopy(cp, mtod(m, caddr_t), (unsigned)len);
    654                 cp += len;
    655                 *mp = m;
    656                 mp = &m->m_next;
    657                 totlen -= len;
    658                 if (cp == epkt)
    659                         cp = buf;
    660         }
    661 
    662         return top;
    663 }
    664 
    665 /*
    666  * Process an ioctl request. This code needs some work - it looks pretty ugly.
    667  */
    668 static int
    669 el_ioctl(ifp, cmd, data)
    670 	register struct ifnet *ifp;
    671 	int cmd;
    672 	caddr_t data;
    673 {
    674 	struct el_softc *sc = elcd.cd_devs[ifp->if_unit];
    675 	struct ifaddr *ifa = (struct ifaddr *)data;
    676 	struct ifreq *ifr = (struct ifreq *)data;
    677 	int s, error = 0;
    678 
    679 	s = splimp();
    680 
    681 	switch (cmd) {
    682 
    683 	case SIOCSIFADDR:
    684 		ifp->if_flags |= IFF_UP;
    685 
    686 		switch (ifa->ifa_addr->sa_family) {
    687 #ifdef INET
    688 		case AF_INET:
    689 			el_init(sc);	/* before arpwhohas */
    690 			/*
    691 			 * See if another station has *our* IP address.
    692 			 * i.e.: There is an address conflict! If a
    693 			 * conflict exists, a message is sent to the
    694 			 * console.
    695 			 */
    696 			sc->sc_arpcom.ac_ipaddr = IA_SIN(ifa)->sin_addr;
    697 			arpwhohas(&sc->sc_arpcom, &IA_SIN(ifa)->sin_addr);
    698 			break;
    699 #endif
    700 #ifdef NS
    701 		/*
    702 		 * XXX - This code is probably wrong.
    703 		 */
    704 		case AF_NS:
    705 		    {
    706 			register struct ns_addr *ina = &IA_SNS(ifa)->sns_addr;
    707 
    708 			if (ns_nullhost(*ina))
    709 				ina->x_host =
    710 				    *(union ns_host *)(sc->sc_arpcom.ac_enaddr);
    711 			else {
    712 				/*
    713 				 *
    714 				 */
    715 				bcopy((caddr_t)ina->x_host.c_host,
    716 				    (caddr_t)sc->sc_arpcom.ac_enaddr,
    717 				    sizeof(sc->sc_arpcom.ac_enaddr));
    718 			}
    719 			/* Set new address. */
    720 			el_init(sc);
    721 			break;
    722 		    }
    723 #endif
    724 		default:
    725 			el_init(sc);
    726 			break;
    727 		}
    728 		break;
    729 
    730 	case SIOCSIFFLAGS:
    731 		if ((ifp->if_flags & IFF_UP) == 0 &&
    732 		    (ifp->if_flags & IFF_RUNNING) != 0) {
    733 			/*
    734 			 * If interface is marked down and it is running, then
    735 			 * stop it.
    736 			 */
    737 			el_stop(sc);
    738 			ifp->if_flags &= ~IFF_RUNNING;
    739 		} else if ((ifp->if_flags & IFF_UP) != 0 &&
    740 		    	   (ifp->if_flags & IFF_RUNNING) == 0) {
    741 			/*
    742 			 * If interface is marked up and it is stopped, then
    743 			 * start it.
    744 			 */
    745 			el_init(sc);
    746 		} else {
    747 			/*
    748 			 * Some other important flag might have changed, so
    749 			 * reset.
    750 			 */
    751 			el_reset(sc);
    752 		}
    753 
    754 	default:
    755 		error = EINVAL;
    756 	}
    757 	(void) splx(s);
    758 	return error;
    759 }
    760 
    761 /*
    762  * Device timeout routine.
    763  */
    764 static int
    765 el_watchdog(unit)
    766 	int unit;
    767 {
    768 	struct el_softc *sc = elcd.cd_devs[unit];
    769 
    770 	log(LOG_ERR, "%s: device timeout\n", sc->sc_dev.dv_xname);
    771 	sc->sc_arpcom.ac_if.if_oerrors++;
    772 
    773 	el_reset(sc);
    774 }
    775