xref: /dragonfly/sys/dev/netif/plip/if_plip.c (revision b1e9d17a)
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 1.13 2005/08/29 10:19:52 sephe 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 #include <sys/thread2.h>
94 
95 #include <machine/clock.h>
96 #include <machine/bus.h>
97 #include <machine/resource.h>
98 #include <sys/rman.h>
99 
100 #include <net/if.h>
101 #include <net/ifq_var.h>
102 #include <net/if_types.h>
103 #include <net/netisr.h>
104 
105 #include <netinet/in.h>
106 #include <netinet/in_var.h>
107 
108 #include <net/bpf.h>
109 
110 #include <bus/ppbus/ppbconf.h>
111 #include "ppbus_if.h"
112 #include <bus/ppbus/ppbio.h>
113 
114 #ifndef LPMTU			/* MTU for the lp# interfaces */
115 #define	LPMTU	1500
116 #endif
117 
118 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
119 #define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
120 #endif
121 
122 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
123 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
124 #endif
125 
126 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
127 #define	LPMAXERRS	100
128 #endif
129 
130 #define CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
131 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
132 #define MLPIPHDRLEN	CLPIPHDRLEN
133 
134 #define LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
135 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
136 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
137 #define MLPIPHDRLEN	LPIPHDRLEN
138 #endif
139 
140 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
141 
142 #define lprintf		if (lptflag) printf
143 
144 #ifdef PLIP_DEBUG
145 static int volatile lptflag = 1;
146 #else
147 static int volatile lptflag = 0;
148 #endif
149 
150 struct lp_data {
151 	unsigned short lp_unit;
152 
153 	struct  ifnet	sc_if;
154 	u_char		*sc_ifbuf;
155 	int		sc_iferrs;
156 
157 	struct resource *res_irq;
158 };
159 
160 /* Tables for the lp# interface */
161 static u_char *txmith;
162 #define txmitl (txmith+(1*LPIPTBLSIZE))
163 #define trecvh (txmith+(2*LPIPTBLSIZE))
164 #define trecvl (txmith+(3*LPIPTBLSIZE))
165 
166 static u_char *ctxmith;
167 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
168 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
169 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
170 
171 /* Functions for the lp# interface */
172 static int lpinittables(void);
173 static int lpioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
174 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
175 	struct rtentry *);
176 static void lp_intr(void *);
177 
178 #define DEVTOSOFTC(dev) \
179 	((struct lp_data *)device_get_softc(dev))
180 #define UNITOSOFTC(unit) \
181 	((struct lp_data *)devclass_get_softc(lp_devclass, (unit)))
182 #define UNITODEVICE(unit) \
183 	(devclass_get_device(lp_devclass, (unit)))
184 
185 static devclass_t lp_devclass;
186 
187 static void
188 lp_identify(driver_t *driver, device_t parent)
189 {
190 
191 	BUS_ADD_CHILD(parent, 0, "plip", 0);
192 }
193 /*
194  * lpprobe()
195  */
196 static int
197 lp_probe(device_t dev)
198 {
199 	device_t ppbus = device_get_parent(dev);
200 	struct lp_data *lp;
201 	int zero = 0;
202 	uintptr_t irq;
203 
204 	lp = DEVTOSOFTC(dev);
205 
206 	/* retrieve the ppbus irq */
207 	BUS_READ_IVAR(ppbus, dev, PPBUS_IVAR_IRQ, &irq);
208 
209 	/* if we haven't interrupts, the probe fails */
210 	if (irq == -1) {
211 		device_printf(dev, "not an interrupt driven port, failed.\n");
212 		return (ENXIO);
213 	}
214 
215 	/* reserve the interrupt resource, expecting irq is available to continue */
216 	lp->res_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &zero, irq, irq, 1,
217 					 RF_SHAREABLE);
218 	if (lp->res_irq == 0) {
219 		device_printf(dev, "cannot reserve interrupt, failed.\n");
220 		return (ENXIO);
221 	}
222 
223 	/*
224 	 * lp dependent initialisation.
225 	 */
226 	lp->lp_unit = device_get_unit(dev);
227 
228 	device_set_desc(dev, "PLIP network interface");
229 
230 	return (0);
231 }
232 
233 static int
234 lp_attach (device_t dev)
235 {
236 	struct lp_data *lp = DEVTOSOFTC(dev);
237 	struct ifnet *ifp = &lp->sc_if;
238 
239 	ifp->if_softc = lp;
240 	if_initname(ifp, "lp", device_get_unit(dev));
241 	ifp->if_mtu = LPMTU;
242 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
243 	ifp->if_ioctl = lpioctl;
244 	ifp->if_output = lpoutput;
245 	ifp->if_type = IFT_PARA;
246 	ifp->if_hdrlen = 0;
247 	ifp->if_addrlen = 0;
248 	ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
249 	if_attach(ifp);
250 
251 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
252 
253 	return (0);
254 }
255 /*
256  * Build the translation tables for the LPIP (BSD unix) protocol.
257  * We don't want to calculate these nasties in our tight loop, so we
258  * precalculate them when we initialize.
259  */
260 static int
261 lpinittables (void)
262 {
263     int i;
264 
265     if (!txmith)
266 	txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
267 
268     if (!ctxmith)
269 	ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
270 
271     for (i=0; i < LPIPTBLSIZE; i++) {
272 	ctxmith[i] = (i & 0xF0) >> 4;
273 	ctxmitl[i] = 0x10 | (i & 0x0F);
274 	ctrecvh[i] = (i & 0x78) << 1;
275 	ctrecvl[i] = (i & 0x78) >> 3;
276     }
277 
278     for (i=0; i < LPIPTBLSIZE; i++) {
279 	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
280 	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
281 	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
282 	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
283     }
284 
285     return 0;
286 }
287 
288 /*
289  * Process an ioctl request.
290  */
291 
292 static int
293 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
294 {
295     device_t dev = UNITODEVICE(ifp->if_dunit);
296     device_t ppbus = device_get_parent(dev);
297     struct lp_data *sc = DEVTOSOFTC(dev);
298     struct ifaddr *ifa = (struct ifaddr *)data;
299     struct ifreq *ifr = (struct ifreq *)data;
300     u_char *ptr;
301     void *ih;
302     int error;
303 
304     switch (cmd) {
305 
306     case SIOCSIFDSTADDR:
307     case SIOCAIFADDR:
308     case SIOCSIFADDR:
309 	if (ifa->ifa_addr->sa_family != AF_INET)
310 	    return EAFNOSUPPORT;
311 
312 	ifp->if_flags |= IFF_UP;
313 	/* FALLTHROUGH */
314     case SIOCSIFFLAGS:
315 	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
316 
317 	    ppb_wctr(ppbus, 0x00);
318 	    ifp->if_flags &= ~IFF_RUNNING;
319 
320 	    /* IFF_UP is not set, try to release the bus anyway */
321 	    ppb_release_bus(ppbus, dev);
322 	    break;
323 	}
324 	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
325 
326 	    /* XXX
327 	     * Should the request be interruptible?
328 	     */
329 	    if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
330 		return (error);
331 
332 	    /* Now IFF_UP means that we own the bus */
333 
334 	    ppb_set_mode(ppbus, PPB_COMPATIBLE);
335 
336 	    if (lpinittables()) {
337 		ppb_release_bus(ppbus, dev);
338 		return ENOBUFS;
339 	    }
340 
341 	    sc->sc_ifbuf = malloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
342 				  M_DEVBUF, M_WAITOK);
343 	    if (!sc->sc_ifbuf) {
344 		ppb_release_bus(ppbus, dev);
345 		return ENOBUFS;
346 	    }
347 
348 	    /* attach our interrupt handler, later detached when the bus is released */
349 	    error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq, INTR_TYPE_NET,
350 				   lp_intr, dev, &ih, NULL);
351 	    if (error) {
352 		ppb_release_bus(ppbus, dev);
353 		return (error);
354 	    }
355 
356 	    ppb_wctr(ppbus, IRQENABLE);
357 	    ifp->if_flags |= IFF_RUNNING;
358 	}
359 	break;
360 
361     case SIOCSIFMTU:
362 	ptr = sc->sc_ifbuf;
363 	sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
364 	if (ptr)
365 	    free(ptr,M_DEVBUF);
366 	sc->sc_if.if_mtu = ifr->ifr_mtu;
367 	break;
368 
369     case SIOCGIFMTU:
370 	ifr->ifr_mtu = sc->sc_if.if_mtu;
371 	break;
372 
373     case SIOCADDMULTI:
374     case SIOCDELMULTI:
375 	if (ifr == 0) {
376 	    return EAFNOSUPPORT;		/* XXX */
377 	}
378 	switch (ifr->ifr_addr.sa_family) {
379 
380 	case AF_INET:
381 	    break;
382 
383 	default:
384 	    return EAFNOSUPPORT;
385 	}
386 	break;
387 
388     case SIOCGIFMEDIA:
389 	/*
390 	 * No ifmedia support at this stage; maybe use it
391 	 * in future for eg. protocol selection.
392 	 */
393 	return EINVAL;
394 
395     default:
396 	lprintf("LP:ioctl(0x%lx)\n", cmd);
397 	return EINVAL;
398     }
399     return 0;
400 }
401 
402 static __inline int
403 clpoutbyte (u_char byte, int spin, device_t ppbus)
404 {
405 	ppb_wdtr(ppbus, ctxmitl[byte]);
406 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
407 		if (--spin == 0) {
408 			return 1;
409 		}
410 	ppb_wdtr(ppbus, ctxmith[byte]);
411 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
412 		if (--spin == 0) {
413 			return 1;
414 		}
415 	return 0;
416 }
417 
418 static __inline int
419 clpinbyte (int spin, device_t ppbus)
420 {
421 	u_char c, cl;
422 
423 	while((ppb_rstr(ppbus) & CLPIP_SHAKE))
424 	    if(!--spin) {
425 		return -1;
426 	    }
427 	cl = ppb_rstr(ppbus);
428 	ppb_wdtr(ppbus, 0x10);
429 
430 	while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
431 	    if(!--spin) {
432 		return -1;
433 	    }
434 	c = ppb_rstr(ppbus);
435 	ppb_wdtr(ppbus, 0x00);
436 
437 	return (ctrecvl[cl] | ctrecvh[c]);
438 }
439 
440 static void
441 lptap(struct ifnet *ifp, struct mbuf *m)
442 {
443 	/*
444 	 * We need to prepend the address family as a four byte field.
445 	 */
446 	static const uint32_t af = AF_INET;
447 
448 	if (ifp->if_bpf)
449 		bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
450 }
451 
452 static void
453 lp_intr (void *arg)
454 {
455 	device_t dev = (device_t)arg;
456         device_t ppbus = device_get_parent(dev);
457 	struct lp_data *sc = DEVTOSOFTC(dev);
458 	int len, j;
459 	u_char *bp;
460 	u_char c, cl;
461 	struct mbuf *top;
462 
463 	crit_enter();
464 
465 	if (sc->sc_if.if_flags & IFF_LINK0) {
466 
467 	    /* Ack. the request */
468 	    ppb_wdtr(ppbus, 0x01);
469 
470 	    /* Get the packet length */
471 	    j = clpinbyte(LPMAXSPIN2, ppbus);
472 	    if (j == -1)
473 		goto err;
474 	    len = j;
475 	    j = clpinbyte(LPMAXSPIN2, ppbus);
476 	    if (j == -1)
477 		goto err;
478 	    len = len + (j << 8);
479 	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
480 		goto err;
481 
482 	    bp  = sc->sc_ifbuf;
483 
484 	    while (len--) {
485 	        j = clpinbyte(LPMAXSPIN2, ppbus);
486 	        if (j == -1) {
487 		    goto err;
488 	        }
489 	        *bp++ = j;
490 	    }
491 	    /* Get and ignore checksum */
492 	    j = clpinbyte(LPMAXSPIN2, ppbus);
493 	    if (j == -1) {
494 	        goto err;
495 	    }
496 
497 	    len = bp - sc->sc_ifbuf;
498 	    if (len <= CLPIPHDRLEN)
499 	        goto err;
500 
501 	    sc->sc_iferrs = 0;
502 
503 	    len -= CLPIPHDRLEN;
504 	    sc->sc_if.if_ipackets++;
505 	    sc->sc_if.if_ibytes += len;
506 	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
507 	    if (top) {
508 		if (sc->sc_if.if_bpf)
509 		    lptap(&sc->sc_if, top);
510 		netisr_queue(NETISR_IP, top);
511 	    }
512 	    goto done;
513 	}
514 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
515 	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
516 	    bp  = sc->sc_ifbuf;
517 	    while (len--) {
518 
519 		cl = ppb_rstr(ppbus);
520 		ppb_wdtr(ppbus, 8);
521 
522 		j = LPMAXSPIN2;
523 		while((ppb_rstr(ppbus) & LPIP_SHAKE))
524 		    if(!--j) goto err;
525 
526 		c = ppb_rstr(ppbus);
527 		ppb_wdtr(ppbus, 0);
528 
529 		*bp++= trecvh[cl] | trecvl[c];
530 
531 		j = LPMAXSPIN2;
532 		while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
533 		    if (cl != c &&
534 			(((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
535 			  (c & 0xf8))
536 			goto end;
537 		    if (!--j) goto err;
538 		}
539 	    }
540 
541 	end:
542 	    len = bp - sc->sc_ifbuf;
543 	    if (len <= LPIPHDRLEN)
544 		goto err;
545 
546 	    sc->sc_iferrs = 0;
547 
548 	    len -= LPIPHDRLEN;
549 	    sc->sc_if.if_ipackets++;
550 	    sc->sc_if.if_ibytes += len;
551 	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
552 	    if (top) {
553 		if (sc->sc_if.if_bpf)
554 		    lptap(&sc->sc_if, top);
555 		netisr_queue(NETISR_IP, top);
556 	    }
557 	}
558 	goto done;
559 
560     err:
561 	ppb_wdtr(ppbus, 0);
562 	lprintf("R");
563 	sc->sc_if.if_ierrors++;
564 	sc->sc_iferrs++;
565 
566 	/*
567 	 * We are not able to send receive anything for now,
568 	 * so stop wasting our time
569 	 */
570 	if (sc->sc_iferrs > LPMAXERRS) {
571 	    printf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
572 	    ppb_wctr(ppbus, 0x00);
573 	    sc->sc_if.if_flags &= ~IFF_RUNNING;
574 	    sc->sc_iferrs=0;
575 	}
576 
577     done:
578 	crit_exit();
579 	return;
580 }
581 
582 static __inline int
583 lpoutbyte (u_char byte, int spin, device_t ppbus)
584 {
585     ppb_wdtr(ppbus, txmith[byte]);
586     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
587 	if (--spin == 0)
588 		return 1;
589     ppb_wdtr(ppbus, txmitl[byte]);
590     while (ppb_rstr(ppbus) & LPIP_SHAKE)
591 	if (--spin == 0)
592 		return 1;
593     return 0;
594 }
595 
596 static int
597 lpoutput (struct ifnet *ifp, struct mbuf *m,
598 	  struct sockaddr *dst, struct rtentry *rt)
599 {
600     device_t dev = UNITODEVICE(ifp->if_dunit);
601     device_t ppbus = device_get_parent(dev);
602     int err;
603     struct mbuf *mm;
604     u_char *cp = "\0\0";
605     u_char chksum = 0;
606     int count = 0;
607     int i, len, spin;
608 
609     /* We need a sensible value if we abort */
610     cp++;
611     ifp->if_flags |= IFF_RUNNING;
612 
613     err = 1;			/* assume we're aborting because of an error */
614 
615     crit_enter();
616 
617     /* Suspend (on laptops) or receive-errors might have taken us offline */
618     ppb_wctr(ppbus, IRQENABLE);
619 
620     if (ifp->if_flags & IFF_LINK0) {
621 
622 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
623 	    lprintf("&");
624 	    lp_intr(dev);
625 	}
626 
627 	/* Alert other end to pending packet */
628 	spin = LPMAXSPIN1;
629 	ppb_wdtr(ppbus, 0x08);
630 	while ((ppb_rstr(ppbus) & 0x08) == 0)
631 		if (--spin == 0) {
632 			goto nend;
633 		}
634 
635 	/* Calculate length of packet, then send that */
636 
637 	count += 14;		/* Ethernet header len */
638 
639 	mm = m;
640 	for (mm = m; mm; mm = mm->m_next) {
641 		count += mm->m_len;
642 	}
643 	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
644 		goto nend;
645 	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
646 		goto nend;
647 
648 	/* Send dummy ethernet header */
649 	for (i = 0; i < 12; i++) {
650 		if (clpoutbyte(i, LPMAXSPIN1, ppbus))
651 			goto nend;
652 		chksum += i;
653 	}
654 
655 	if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
656 		goto nend;
657 	if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
658 		goto nend;
659 	chksum += 0x08 + 0x00;		/* Add into checksum */
660 
661 	mm = m;
662 	do {
663 		cp = mtod(mm, u_char *);
664 		len = mm->m_len;
665 		while (len--) {
666 			chksum += *cp;
667 			if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
668 				goto nend;
669 		}
670 	} while ((mm = mm->m_next));
671 
672 	/* Send checksum */
673 	if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
674 		goto nend;
675 
676 	/* Go quiescent */
677 	ppb_wdtr(ppbus, 0);
678 
679 	err = 0;			/* No errors */
680 
681 	nend:
682 	if (err)  {				/* if we didn't timeout... */
683 		ifp->if_oerrors++;
684 		lprintf("X");
685 	} else {
686 		ifp->if_opackets++;
687 		ifp->if_obytes += m->m_pkthdr.len;
688 		if (ifp->if_bpf)
689 		    lptap(ifp, m);
690 	}
691 
692 	m_freem(m);
693 
694 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
695 		lprintf("^");
696 		lp_intr(dev);
697 	}
698 	crit_exit();
699 	return 0;
700     }
701 
702     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
703         lprintf("&");
704         lp_intr(dev);
705     }
706 
707     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
708         goto end;
709     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
710         goto end;
711 
712     mm = m;
713     do {
714         cp = mtod(mm,u_char *);
715 	len = mm->m_len;
716         while (len--)
717 	    if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
718 	        goto end;
719     } while ((mm = mm->m_next));
720 
721     err = 0;				/* no errors were encountered */
722 
723     end:
724     --cp;
725     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
726 
727     if (err)  {				/* if we didn't timeout... */
728 	ifp->if_oerrors++;
729         lprintf("X");
730     } else {
731 	ifp->if_opackets++;
732 	ifp->if_obytes += m->m_pkthdr.len;
733 	if (ifp->if_bpf)
734 	    lptap(ifp, m);
735     }
736 
737     m_freem(m);
738 
739     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
740 	lprintf("^");
741 	lp_intr(dev);
742     }
743 
744     crit_exit();
745     return 0;
746 }
747 
748 static device_method_t lp_methods[] = {
749   	/* device interface */
750 	DEVMETHOD(device_identify,	lp_identify),
751 	DEVMETHOD(device_probe,		lp_probe),
752 	DEVMETHOD(device_attach,	lp_attach),
753 
754 	{ 0, 0 }
755 };
756 
757 static driver_t lp_driver = {
758   "plip",
759   lp_methods,
760   sizeof(struct lp_data),
761 };
762 
763 DECLARE_DUMMY_MODULE(if_plip);
764 DRIVER_MODULE(if_plip, ppbus, lp_driver, lp_devclass, 0, 0);
765 
766