xref: /dragonfly/sys/dev/netif/plip/if_plip.c (revision c9f721c2)
1 /*-
2  * Copyright (c) 1997 Poul-Henning Kamp
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  *
26  *	From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp
27  * $FreeBSD: src/sys/dev/ppbus/if_plip.c,v 1.19.2.1 2000/05/24 00:20:57 n_hibma Exp $
28  * $DragonFly: src/sys/dev/netif/plip/if_plip.c,v 1.8 2004/04/07 05:45:29 dillon Exp $
29  */
30 
31 /*
32  * Parallel port TCP/IP interfaces added.  I looked at the driver from
33  * MACH but this is a complete rewrite, and btw. incompatible, and it
34  * should perform better too.  I have never run the MACH driver though.
35  *
36  * This driver sends two bytes (0x08, 0x00) in front of each packet,
37  * to allow us to distinguish another format later.
38  *
39  * Now added an Linux/Crynwr compatibility mode which is enabled using
40  * IF_LINK0 - Tim Wilkinson.
41  *
42  * TODO:
43  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
44  *
45  * Connect the two computers using a Laplink parallel cable to use this
46  * feature:
47  *
48  *      +----------------------------------------+
49  * 	|A-name	A-End	B-End	Descr.	Port/Bit |
50  *      +----------------------------------------+
51  *	|DATA0	2	15	Data	0/0x01   |
52  *	|-ERROR	15	2	   	1/0x08   |
53  *      +----------------------------------------+
54  *	|DATA1	3	13	Data	0/0x02	 |
55  *	|+SLCT	13	3	   	1/0x10   |
56  *      +----------------------------------------+
57  *	|DATA2	4	12	Data	0/0x04   |
58  *	|+PE	12	4	   	1/0x20   |
59  *      +----------------------------------------+
60  *	|DATA3	5	10	Strobe	0/0x08   |
61  *	|-ACK	10	5	   	1/0x40   |
62  *      +----------------------------------------+
63  *	|DATA4	6	11	Data	0/0x10   |
64  *	|BUSY	11	6	   	1/~0x80  |
65  *      +----------------------------------------+
66  *	|GND	18-25	18-25	GND	-        |
67  *      +----------------------------------------+
68  *
69  * Expect transfer-rates up to 75 kbyte/sec.
70  *
71  * If GCC could correctly grok
72  *	register int port asm("edx")
73  * the code would be cleaner
74  *
75  * Poul-Henning Kamp <phk@freebsd.org>
76  */
77 
78 /*
79  * Update for ppbus, PLIP support only - Nicolas Souchu
80  */
81 
82 #include "opt_plip.h"
83 
84 #include <sys/param.h>
85 #include <sys/systm.h>
86 #include <sys/module.h>
87 #include <sys/bus.h>
88 #include <sys/mbuf.h>
89 #include <sys/socket.h>
90 #include <sys/sockio.h>
91 #include <sys/kernel.h>
92 #include <sys/malloc.h>
93 
94 #include <machine/clock.h>
95 #include <machine/bus.h>
96 #include <machine/resource.h>
97 #include <sys/rman.h>
98 
99 #include <net/if.h>
100 #include <net/if_types.h>
101 #include <net/netisr.h>
102 
103 #include <netinet/in.h>
104 #include <netinet/in_var.h>
105 
106 #include <net/bpf.h>
107 
108 #include <bus/ppbus/ppbconf.h>
109 #include "ppbus_if.h"
110 #include <bus/ppbus/ppbio.h>
111 
112 #ifndef LPMTU			/* MTU for the lp# interfaces */
113 #define	LPMTU	1500
114 #endif
115 
116 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
117 #define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
118 #endif
119 
120 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
121 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
122 #endif
123 
124 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
125 #define	LPMAXERRS	100
126 #endif
127 
128 #define CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
129 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
130 #define MLPIPHDRLEN	CLPIPHDRLEN
131 
132 #define LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
133 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
134 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
135 #define MLPIPHDRLEN	LPIPHDRLEN
136 #endif
137 
138 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
139 
140 #define lprintf		if (lptflag) printf
141 
142 #ifdef PLIP_DEBUG
143 static int volatile lptflag = 1;
144 #else
145 static int volatile lptflag = 0;
146 #endif
147 
148 struct lp_data {
149 	unsigned short lp_unit;
150 
151 	struct  ifnet	sc_if;
152 	u_char		*sc_ifbuf;
153 	int		sc_iferrs;
154 
155 	struct resource *res_irq;
156 };
157 
158 /* Tables for the lp# interface */
159 static u_char *txmith;
160 #define txmitl (txmith+(1*LPIPTBLSIZE))
161 #define trecvh (txmith+(2*LPIPTBLSIZE))
162 #define trecvl (txmith+(3*LPIPTBLSIZE))
163 
164 static u_char *ctxmith;
165 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
166 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
167 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
168 
169 /* Functions for the lp# interface */
170 static int lpinittables(void);
171 static int lpioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
172 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
173 	struct rtentry *);
174 static void lp_intr(void *);
175 
176 #define DEVTOSOFTC(dev) \
177 	((struct lp_data *)device_get_softc(dev))
178 #define UNITOSOFTC(unit) \
179 	((struct lp_data *)devclass_get_softc(lp_devclass, (unit)))
180 #define UNITODEVICE(unit) \
181 	(devclass_get_device(lp_devclass, (unit)))
182 
183 static devclass_t lp_devclass;
184 
185 static void
186 lp_identify(driver_t *driver, device_t parent)
187 {
188 
189 	BUS_ADD_CHILD(parent, 0, "plip", 0);
190 }
191 /*
192  * lpprobe()
193  */
194 static int
195 lp_probe(device_t dev)
196 {
197 	device_t ppbus = device_get_parent(dev);
198 	struct lp_data *lp;
199 	int zero = 0;
200 	uintptr_t irq;
201 
202 	lp = DEVTOSOFTC(dev);
203 	bzero(lp, sizeof(struct lp_data));
204 
205 	/* retrieve the ppbus irq */
206 	BUS_READ_IVAR(ppbus, dev, PPBUS_IVAR_IRQ, &irq);
207 
208 	/* if we haven't interrupts, the probe fails */
209 	if (irq == -1) {
210 		device_printf(dev, "not an interrupt driven port, failed.\n");
211 		return (ENXIO);
212 	}
213 
214 	/* reserve the interrupt resource, expecting irq is available to continue */
215 	lp->res_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &zero, irq, irq, 1,
216 					 RF_SHAREABLE);
217 	if (lp->res_irq == 0) {
218 		device_printf(dev, "cannot reserve interrupt, failed.\n");
219 		return (ENXIO);
220 	}
221 
222 	/*
223 	 * lp dependent initialisation.
224 	 */
225 	lp->lp_unit = device_get_unit(dev);
226 
227 	device_set_desc(dev, "PLIP network interface");
228 
229 	return (0);
230 }
231 
232 static int
233 lp_attach (device_t dev)
234 {
235 	struct lp_data *lp = DEVTOSOFTC(dev);
236 	struct ifnet *ifp = &lp->sc_if;
237 
238 	ifp->if_softc = lp;
239 	if_initname(ifp, "lp", device_get_unit(dev));
240 	ifp->if_mtu = LPMTU;
241 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
242 	ifp->if_ioctl = lpioctl;
243 	ifp->if_output = lpoutput;
244 	ifp->if_type = IFT_PARA;
245 	ifp->if_hdrlen = 0;
246 	ifp->if_addrlen = 0;
247 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
248 	if_attach(ifp);
249 
250 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
251 
252 	return (0);
253 }
254 /*
255  * Build the translation tables for the LPIP (BSD unix) protocol.
256  * We don't want to calculate these nasties in our tight loop, so we
257  * precalculate them when we initialize.
258  */
259 static int
260 lpinittables (void)
261 {
262     int i;
263 
264     if (!txmith)
265 	txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
266 
267     if (!ctxmith)
268 	ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
269 
270     for (i=0; i < LPIPTBLSIZE; i++) {
271 	ctxmith[i] = (i & 0xF0) >> 4;
272 	ctxmitl[i] = 0x10 | (i & 0x0F);
273 	ctrecvh[i] = (i & 0x78) << 1;
274 	ctrecvl[i] = (i & 0x78) >> 3;
275     }
276 
277     for (i=0; i < LPIPTBLSIZE; i++) {
278 	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
279 	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
280 	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
281 	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
282     }
283 
284     return 0;
285 }
286 
287 /*
288  * Process an ioctl request.
289  */
290 
291 static int
292 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
293 {
294     device_t dev = UNITODEVICE(ifp->if_dunit);
295     device_t ppbus = device_get_parent(dev);
296     struct lp_data *sc = DEVTOSOFTC(dev);
297     struct ifaddr *ifa = (struct ifaddr *)data;
298     struct ifreq *ifr = (struct ifreq *)data;
299     u_char *ptr;
300     void *ih;
301     int error;
302 
303     switch (cmd) {
304 
305     case SIOCSIFDSTADDR:
306     case SIOCAIFADDR:
307     case SIOCSIFADDR:
308 	if (ifa->ifa_addr->sa_family != AF_INET)
309 	    return EAFNOSUPPORT;
310 
311 	ifp->if_flags |= IFF_UP;
312 	/* FALLTHROUGH */
313     case SIOCSIFFLAGS:
314 	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
315 
316 	    ppb_wctr(ppbus, 0x00);
317 	    ifp->if_flags &= ~IFF_RUNNING;
318 
319 	    /* IFF_UP is not set, try to release the bus anyway */
320 	    ppb_release_bus(ppbus, dev);
321 	    break;
322 	}
323 	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
324 
325 	    /* XXX
326 	     * Should the request be interruptible?
327 	     */
328 	    if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
329 		return (error);
330 
331 	    /* Now IFF_UP means that we own the bus */
332 
333 	    ppb_set_mode(ppbus, PPB_COMPATIBLE);
334 
335 	    if (lpinittables()) {
336 		ppb_release_bus(ppbus, dev);
337 		return ENOBUFS;
338 	    }
339 
340 	    sc->sc_ifbuf = malloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
341 				  M_DEVBUF, M_WAITOK);
342 	    if (!sc->sc_ifbuf) {
343 		ppb_release_bus(ppbus, dev);
344 		return ENOBUFS;
345 	    }
346 
347 	    /* attach our interrupt handler, later detached when the bus is released */
348 	    if ((error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq,
349 					INTR_TYPE_NET, lp_intr, dev, &ih))) {
350 		ppb_release_bus(ppbus, dev);
351 		return (error);
352 	    }
353 
354 	    ppb_wctr(ppbus, IRQENABLE);
355 	    ifp->if_flags |= IFF_RUNNING;
356 	}
357 	break;
358 
359     case SIOCSIFMTU:
360 	ptr = sc->sc_ifbuf;
361 	sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
362 	if (ptr)
363 	    free(ptr,M_DEVBUF);
364 	sc->sc_if.if_mtu = ifr->ifr_mtu;
365 	break;
366 
367     case SIOCGIFMTU:
368 	ifr->ifr_mtu = sc->sc_if.if_mtu;
369 	break;
370 
371     case SIOCADDMULTI:
372     case SIOCDELMULTI:
373 	if (ifr == 0) {
374 	    return EAFNOSUPPORT;		/* XXX */
375 	}
376 	switch (ifr->ifr_addr.sa_family) {
377 
378 	case AF_INET:
379 	    break;
380 
381 	default:
382 	    return EAFNOSUPPORT;
383 	}
384 	break;
385 
386     case SIOCGIFMEDIA:
387 	/*
388 	 * No ifmedia support at this stage; maybe use it
389 	 * in future for eg. protocol selection.
390 	 */
391 	return EINVAL;
392 
393     default:
394 	lprintf("LP:ioctl(0x%lx)\n", cmd);
395 	return EINVAL;
396     }
397     return 0;
398 }
399 
400 static __inline int
401 clpoutbyte (u_char byte, int spin, device_t ppbus)
402 {
403 	ppb_wdtr(ppbus, ctxmitl[byte]);
404 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
405 		if (--spin == 0) {
406 			return 1;
407 		}
408 	ppb_wdtr(ppbus, ctxmith[byte]);
409 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
410 		if (--spin == 0) {
411 			return 1;
412 		}
413 	return 0;
414 }
415 
416 static __inline int
417 clpinbyte (int spin, device_t ppbus)
418 {
419 	u_char c, cl;
420 
421 	while((ppb_rstr(ppbus) & CLPIP_SHAKE))
422 	    if(!--spin) {
423 		return -1;
424 	    }
425 	cl = ppb_rstr(ppbus);
426 	ppb_wdtr(ppbus, 0x10);
427 
428 	while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
429 	    if(!--spin) {
430 		return -1;
431 	    }
432 	c = ppb_rstr(ppbus);
433 	ppb_wdtr(ppbus, 0x00);
434 
435 	return (ctrecvl[cl] | ctrecvh[c]);
436 }
437 
438 static void
439 lptap(struct ifnet *ifp, struct mbuf *m)
440 {
441 	/*
442 	 * Send a packet through bpf. We need to prepend the address family
443 	 * as a four byte field. Cons up a dummy header to pacify bpf. This
444 	 * is safe because bpf will only read from the mbuf (i.e., it won't
445 	 * try to free it or keep a pointer to it).
446 	 */
447 	u_int32_t af = AF_INET;
448 	struct mbuf m0;
449 
450 	m0.m_next = m;
451 	m0.m_len = sizeof(u_int32_t);
452 	m0.m_data = (char *)&af;
453 	bpf_mtap(ifp, &m0);
454 }
455 
456 static void
457 lp_intr (void *arg)
458 {
459 	device_t dev = (device_t)arg;
460         device_t ppbus = device_get_parent(dev);
461 	struct lp_data *sc = DEVTOSOFTC(dev);
462 	int len, s, j;
463 	u_char *bp;
464 	u_char c, cl;
465 	struct mbuf *top;
466 
467 	s = splhigh();
468 
469 	if (sc->sc_if.if_flags & IFF_LINK0) {
470 
471 	    /* Ack. the request */
472 	    ppb_wdtr(ppbus, 0x01);
473 
474 	    /* Get the packet length */
475 	    j = clpinbyte(LPMAXSPIN2, ppbus);
476 	    if (j == -1)
477 		goto err;
478 	    len = j;
479 	    j = clpinbyte(LPMAXSPIN2, ppbus);
480 	    if (j == -1)
481 		goto err;
482 	    len = len + (j << 8);
483 	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
484 		goto err;
485 
486 	    bp  = sc->sc_ifbuf;
487 
488 	    while (len--) {
489 	        j = clpinbyte(LPMAXSPIN2, ppbus);
490 	        if (j == -1) {
491 		    goto err;
492 	        }
493 	        *bp++ = j;
494 	    }
495 	    /* Get and ignore checksum */
496 	    j = clpinbyte(LPMAXSPIN2, ppbus);
497 	    if (j == -1) {
498 	        goto err;
499 	    }
500 
501 	    len = bp - sc->sc_ifbuf;
502 	    if (len <= CLPIPHDRLEN)
503 	        goto err;
504 
505 	    sc->sc_iferrs = 0;
506 
507 	    len -= CLPIPHDRLEN;
508 	    sc->sc_if.if_ipackets++;
509 	    sc->sc_if.if_ibytes += len;
510 	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
511 	    if (top) {
512 		if (sc->sc_if.if_bpf)
513 		    lptap(&sc->sc_if, top);
514 		netisr_queue(NETISR_IP, top);
515 	    }
516 	    goto done;
517 	}
518 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
519 	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
520 	    bp  = sc->sc_ifbuf;
521 	    while (len--) {
522 
523 		cl = ppb_rstr(ppbus);
524 		ppb_wdtr(ppbus, 8);
525 
526 		j = LPMAXSPIN2;
527 		while((ppb_rstr(ppbus) & LPIP_SHAKE))
528 		    if(!--j) goto err;
529 
530 		c = ppb_rstr(ppbus);
531 		ppb_wdtr(ppbus, 0);
532 
533 		*bp++= trecvh[cl] | trecvl[c];
534 
535 		j = LPMAXSPIN2;
536 		while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
537 		    if (cl != c &&
538 			(((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
539 			  (c & 0xf8))
540 			goto end;
541 		    if (!--j) goto err;
542 		}
543 	    }
544 
545 	end:
546 	    len = bp - sc->sc_ifbuf;
547 	    if (len <= LPIPHDRLEN)
548 		goto err;
549 
550 	    sc->sc_iferrs = 0;
551 
552 	    len -= LPIPHDRLEN;
553 	    sc->sc_if.if_ipackets++;
554 	    sc->sc_if.if_ibytes += len;
555 	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
556 	    if (top) {
557 		if (sc->sc_if.if_bpf)
558 		    lptap(&sc->sc_if, top);
559 		netisr_queue(NETISR_IP, top);
560 	    }
561 	}
562 	goto done;
563 
564     err:
565 	ppb_wdtr(ppbus, 0);
566 	lprintf("R");
567 	sc->sc_if.if_ierrors++;
568 	sc->sc_iferrs++;
569 
570 	/*
571 	 * We are not able to send receive anything for now,
572 	 * so stop wasting our time
573 	 */
574 	if (sc->sc_iferrs > LPMAXERRS) {
575 	    printf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
576 	    ppb_wctr(ppbus, 0x00);
577 	    sc->sc_if.if_flags &= ~IFF_RUNNING;
578 	    sc->sc_iferrs=0;
579 	}
580 
581     done:
582 	splx(s);
583 	return;
584 }
585 
586 static __inline int
587 lpoutbyte (u_char byte, int spin, device_t ppbus)
588 {
589     ppb_wdtr(ppbus, txmith[byte]);
590     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
591 	if (--spin == 0)
592 		return 1;
593     ppb_wdtr(ppbus, txmitl[byte]);
594     while (ppb_rstr(ppbus) & LPIP_SHAKE)
595 	if (--spin == 0)
596 		return 1;
597     return 0;
598 }
599 
600 static int
601 lpoutput (struct ifnet *ifp, struct mbuf *m,
602 	  struct sockaddr *dst, struct rtentry *rt)
603 {
604     device_t dev = UNITODEVICE(ifp->if_dunit);
605     device_t ppbus = device_get_parent(dev);
606     int s, err;
607     struct mbuf *mm;
608     u_char *cp = "\0\0";
609     u_char chksum = 0;
610     int count = 0;
611     int i, len, spin;
612 
613     /* We need a sensible value if we abort */
614     cp++;
615     ifp->if_flags |= IFF_RUNNING;
616 
617     err = 1;			/* assume we're aborting because of an error */
618 
619     s = splhigh();
620 
621     /* Suspend (on laptops) or receive-errors might have taken us offline */
622     ppb_wctr(ppbus, IRQENABLE);
623 
624     if (ifp->if_flags & IFF_LINK0) {
625 
626 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
627 	    lprintf("&");
628 	    lp_intr(dev);
629 	}
630 
631 	/* Alert other end to pending packet */
632 	spin = LPMAXSPIN1;
633 	ppb_wdtr(ppbus, 0x08);
634 	while ((ppb_rstr(ppbus) & 0x08) == 0)
635 		if (--spin == 0) {
636 			goto nend;
637 		}
638 
639 	/* Calculate length of packet, then send that */
640 
641 	count += 14;		/* Ethernet header len */
642 
643 	mm = m;
644 	for (mm = m; mm; mm = mm->m_next) {
645 		count += mm->m_len;
646 	}
647 	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
648 		goto nend;
649 	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
650 		goto nend;
651 
652 	/* Send dummy ethernet header */
653 	for (i = 0; i < 12; i++) {
654 		if (clpoutbyte(i, LPMAXSPIN1, ppbus))
655 			goto nend;
656 		chksum += i;
657 	}
658 
659 	if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
660 		goto nend;
661 	if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
662 		goto nend;
663 	chksum += 0x08 + 0x00;		/* Add into checksum */
664 
665 	mm = m;
666 	do {
667 		cp = mtod(mm, u_char *);
668 		len = mm->m_len;
669 		while (len--) {
670 			chksum += *cp;
671 			if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
672 				goto nend;
673 		}
674 	} while ((mm = mm->m_next));
675 
676 	/* Send checksum */
677 	if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
678 		goto nend;
679 
680 	/* Go quiescent */
681 	ppb_wdtr(ppbus, 0);
682 
683 	err = 0;			/* No errors */
684 
685 	nend:
686 	if (err)  {				/* if we didn't timeout... */
687 		ifp->if_oerrors++;
688 		lprintf("X");
689 	} else {
690 		ifp->if_opackets++;
691 		ifp->if_obytes += m->m_pkthdr.len;
692 		if (ifp->if_bpf)
693 		    lptap(ifp, m);
694 	}
695 
696 	m_freem(m);
697 
698 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
699 		lprintf("^");
700 		lp_intr(dev);
701 	}
702 	(void) splx(s);
703 	return 0;
704     }
705 
706     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
707         lprintf("&");
708         lp_intr(dev);
709     }
710 
711     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
712         goto end;
713     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
714         goto end;
715 
716     mm = m;
717     do {
718         cp = mtod(mm,u_char *);
719 	len = mm->m_len;
720         while (len--)
721 	    if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
722 	        goto end;
723     } while ((mm = mm->m_next));
724 
725     err = 0;				/* no errors were encountered */
726 
727     end:
728     --cp;
729     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
730 
731     if (err)  {				/* if we didn't timeout... */
732 	ifp->if_oerrors++;
733         lprintf("X");
734     } else {
735 	ifp->if_opackets++;
736 	ifp->if_obytes += m->m_pkthdr.len;
737 	if (ifp->if_bpf)
738 	    lptap(ifp, m);
739     }
740 
741     m_freem(m);
742 
743     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
744 	lprintf("^");
745 	lp_intr(dev);
746     }
747 
748     (void) splx(s);
749     return 0;
750 }
751 
752 static device_method_t lp_methods[] = {
753   	/* device interface */
754 	DEVMETHOD(device_identify,	lp_identify),
755 	DEVMETHOD(device_probe,		lp_probe),
756 	DEVMETHOD(device_attach,	lp_attach),
757 
758 	{ 0, 0 }
759 };
760 
761 static driver_t lp_driver = {
762   "plip",
763   lp_methods,
764   sizeof(struct lp_data),
765 };
766 
767 DECLARE_DUMMY_MODULE(if_plip);
768 DRIVER_MODULE(if_plip, ppbus, lp_driver, lp_devclass, 0, 0);
769 
770