xref: /freebsd/sys/dev/ppbus/if_plip.c (revision 6b3455a7665208c366849f0b2b3bc916fb97516e)
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  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 /*
33  * Parallel port TCP/IP interfaces added.  I looked at the driver from
34  * MACH but this is a complete rewrite, and btw. incompatible, and it
35  * should perform better too.  I have never run the MACH driver though.
36  *
37  * This driver sends two bytes (0x08, 0x00) in front of each packet,
38  * to allow us to distinguish another format later.
39  *
40  * Now added a Linux/Crynwr compatibility mode which is enabled using
41  * IF_LINK0 - Tim Wilkinson.
42  *
43  * TODO:
44  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
45  *
46  * Connect the two computers using a Laplink parallel cable to use this
47  * feature:
48  *
49  *      +----------------------------------------+
50  * 	|A-name	A-End	B-End	Descr.	Port/Bit |
51  *      +----------------------------------------+
52  *	|DATA0	2	15	Data	0/0x01   |
53  *	|-ERROR	15	2	   	1/0x08   |
54  *      +----------------------------------------+
55  *	|DATA1	3	13	Data	0/0x02	 |
56  *	|+SLCT	13	3	   	1/0x10   |
57  *      +----------------------------------------+
58  *	|DATA2	4	12	Data	0/0x04   |
59  *	|+PE	12	4	   	1/0x20   |
60  *      +----------------------------------------+
61  *	|DATA3	5	10	Strobe	0/0x08   |
62  *	|-ACK	10	5	   	1/0x40   |
63  *      +----------------------------------------+
64  *	|DATA4	6	11	Data	0/0x10   |
65  *	|BUSY	11	6	   	1/~0x80  |
66  *      +----------------------------------------+
67  *	|GND	18-25	18-25	GND	-        |
68  *      +----------------------------------------+
69  *
70  * Expect transfer-rates up to 75 kbyte/sec.
71  *
72  * If GCC could correctly grok
73  *	register int port asm("edx")
74  * the code would be cleaner
75  *
76  * Poul-Henning Kamp <phk@freebsd.org>
77  */
78 
79 /*
80  * Update for ppbus, PLIP support only - Nicolas Souchu
81  */
82 
83 #include "opt_plip.h"
84 
85 #include <sys/param.h>
86 #include <sys/systm.h>
87 #include <sys/module.h>
88 #include <sys/bus.h>
89 #include <sys/mbuf.h>
90 #include <sys/socket.h>
91 #include <sys/sockio.h>
92 #include <sys/kernel.h>
93 #include <sys/malloc.h>
94 
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 <dev/ppbus/ppbconf.h>
109 #include "ppbus_if.h"
110 #include <dev/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 	struct  ifnet	sc_if;
150 	u_char		*sc_ifbuf;
151 	int		sc_iferrs;
152 
153 	struct resource *res_irq;
154 };
155 
156 /* Tables for the lp# interface */
157 static u_char *txmith;
158 #define txmitl (txmith+(1*LPIPTBLSIZE))
159 #define trecvh (txmith+(2*LPIPTBLSIZE))
160 #define trecvl (txmith+(3*LPIPTBLSIZE))
161 
162 static u_char *ctxmith;
163 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
164 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
165 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
166 
167 /* Functions for the lp# interface */
168 static int lpinittables(void);
169 static int lpioctl(struct ifnet *, u_long, caddr_t);
170 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
171 	struct rtentry *);
172 static void lp_intr(void *);
173 
174 #define DEVTOSOFTC(dev) \
175 	((struct lp_data *)device_get_softc(dev))
176 #define UNITOSOFTC(unit) \
177 	((struct lp_data *)devclass_get_softc(lp_devclass, (unit)))
178 #define UNITODEVICE(unit) \
179 	(devclass_get_device(lp_devclass, (unit)))
180 
181 static devclass_t lp_devclass;
182 
183 static void
184 lp_identify(driver_t *driver, device_t parent)
185 {
186 	device_t dev;
187 
188 	dev = device_find_child(parent, "plip", 0);
189 	if (!dev)
190 		BUS_ADD_CHILD(parent, 0, "plip", -1);
191 }
192 /*
193  * lpprobe()
194  */
195 static int
196 lp_probe(device_t dev)
197 {
198 	device_t ppbus = device_get_parent(dev);
199 	struct lp_data *lp;
200 	int zero = 0;
201 	uintptr_t irq;
202 
203 	lp = DEVTOSOFTC(dev);
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 
226 	device_set_desc(dev, "PLIP network interface");
227 
228 	return (0);
229 }
230 
231 static int
232 lp_attach (device_t dev)
233 {
234 	struct lp_data *lp = DEVTOSOFTC(dev);
235 	struct ifnet *ifp = &lp->sc_if;
236 
237 	ifp->if_softc = lp;
238 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
239 	ifp->if_mtu = LPMTU;
240 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
241 	ifp->if_ioctl = lpioctl;
242 	ifp->if_output = lpoutput;
243 	ifp->if_type = IFT_PARA;
244 	ifp->if_hdrlen = 0;
245 	ifp->if_addrlen = 0;
246 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
247 	if_attach(ifp);
248 
249 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
250 
251 	return (0);
252 }
253 /*
254  * Build the translation tables for the LPIP (BSD unix) protocol.
255  * We don't want to calculate these nasties in our tight loop, so we
256  * precalculate them when we initialize.
257  */
258 static int
259 lpinittables (void)
260 {
261     int i;
262 
263     if (!txmith)
264 	txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
265 
266     if (!txmith)
267 	return 1;
268 
269     if (!ctxmith)
270 	ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
271 
272     if (!ctxmith)
273 	return 1;
274 
275     for (i=0; i < LPIPTBLSIZE; i++) {
276 	ctxmith[i] = (i & 0xF0) >> 4;
277 	ctxmitl[i] = 0x10 | (i & 0x0F);
278 	ctrecvh[i] = (i & 0x78) << 1;
279 	ctrecvl[i] = (i & 0x78) >> 3;
280     }
281 
282     for (i=0; i < LPIPTBLSIZE; i++) {
283 	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
284 	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
285 	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
286 	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
287     }
288 
289     return 0;
290 }
291 
292 /*
293  * Process an ioctl request.
294  */
295 
296 static int
297 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data)
298 {
299     device_t dev = UNITODEVICE(ifp->if_dunit);
300     device_t ppbus = device_get_parent(dev);
301     struct lp_data *sc = DEVTOSOFTC(dev);
302     struct ifaddr *ifa = (struct ifaddr *)data;
303     struct ifreq *ifr = (struct ifreq *)data;
304     u_char *ptr;
305     void *ih;
306     int error;
307 
308     switch (cmd) {
309 
310     case SIOCSIFDSTADDR:
311     case SIOCAIFADDR:
312     case SIOCSIFADDR:
313 	if (ifa->ifa_addr->sa_family != AF_INET)
314 	    return EAFNOSUPPORT;
315 
316 	ifp->if_flags |= IFF_UP;
317 	/* FALLTHROUGH */
318     case SIOCSIFFLAGS:
319 	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
320 
321 	    ppb_wctr(ppbus, 0x00);
322 	    ifp->if_flags &= ~IFF_RUNNING;
323 
324 	    /* IFF_UP is not set, try to release the bus anyway */
325 	    ppb_release_bus(ppbus, dev);
326 	    break;
327 	}
328 	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
329 
330 	    /* XXX
331 	     * Should the request be interruptible?
332 	     */
333 	    if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
334 		return (error);
335 
336 	    /* Now IFF_UP means that we own the bus */
337 
338 	    ppb_set_mode(ppbus, PPB_COMPATIBLE);
339 
340 	    if (lpinittables()) {
341 		ppb_release_bus(ppbus, dev);
342 		return ENOBUFS;
343 	    }
344 
345 	    sc->sc_ifbuf = malloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
346 				  M_DEVBUF, M_WAITOK);
347 	    if (!sc->sc_ifbuf) {
348 		ppb_release_bus(ppbus, dev);
349 		return ENOBUFS;
350 	    }
351 
352 	    /* attach our interrupt handler, later detached when the bus is released */
353 	    if ((error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq,
354 					INTR_TYPE_NET, lp_intr, dev, &ih))) {
355 		ppb_release_bus(ppbus, dev);
356 		return (error);
357 	    }
358 
359 	    ppb_wctr(ppbus, IRQENABLE);
360 	    ifp->if_flags |= IFF_RUNNING;
361 	}
362 	break;
363 
364     case SIOCSIFMTU:
365 	ptr = sc->sc_ifbuf;
366 	sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_NOWAIT);
367 	if (!sc->sc_ifbuf) {
368 	    sc->sc_ifbuf = ptr;
369 	    return ENOBUFS;
370 	}
371 	if (ptr)
372 	    free(ptr,M_DEVBUF);
373 	sc->sc_if.if_mtu = ifr->ifr_mtu;
374 	break;
375 
376     case SIOCGIFMTU:
377 	ifr->ifr_mtu = sc->sc_if.if_mtu;
378 	break;
379 
380     case SIOCADDMULTI:
381     case SIOCDELMULTI:
382 	if (ifr == 0) {
383 	    return EAFNOSUPPORT;		/* XXX */
384 	}
385 	switch (ifr->ifr_addr.sa_family) {
386 
387 	case AF_INET:
388 	    break;
389 
390 	default:
391 	    return EAFNOSUPPORT;
392 	}
393 	break;
394 
395     case SIOCGIFMEDIA:
396 	/*
397 	 * No ifmedia support at this stage; maybe use it
398 	 * in future for eg. protocol selection.
399 	 */
400 	return EINVAL;
401 
402     default:
403 	lprintf("LP:ioctl(0x%lx)\n", cmd);
404 	return EINVAL;
405     }
406     return 0;
407 }
408 
409 static __inline int
410 clpoutbyte (u_char byte, int spin, device_t ppbus)
411 {
412 	ppb_wdtr(ppbus, ctxmitl[byte]);
413 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
414 		if (--spin == 0) {
415 			return 1;
416 		}
417 	ppb_wdtr(ppbus, ctxmith[byte]);
418 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
419 		if (--spin == 0) {
420 			return 1;
421 		}
422 	return 0;
423 }
424 
425 static __inline int
426 clpinbyte (int spin, device_t ppbus)
427 {
428 	u_char c, cl;
429 
430 	while((ppb_rstr(ppbus) & CLPIP_SHAKE))
431 	    if(!--spin) {
432 		return -1;
433 	    }
434 	cl = ppb_rstr(ppbus);
435 	ppb_wdtr(ppbus, 0x10);
436 
437 	while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
438 	    if(!--spin) {
439 		return -1;
440 	    }
441 	c = ppb_rstr(ppbus);
442 	ppb_wdtr(ppbus, 0x00);
443 
444 	return (ctrecvl[cl] | ctrecvh[c]);
445 }
446 
447 static void
448 lptap(struct ifnet *ifp, struct mbuf *m)
449 {
450 	u_int32_t af = AF_INET;
451 	BPF_MTAP2(ifp, &af, sizeof(af), m);
452 }
453 
454 static void
455 lp_intr (void *arg)
456 {
457 	device_t dev = (device_t)arg;
458         device_t ppbus = device_get_parent(dev);
459 	struct lp_data *sc = DEVTOSOFTC(dev);
460 	int len, s, j;
461 	u_char *bp;
462 	u_char c, cl;
463 	struct mbuf *top;
464 
465 	s = splhigh();
466 
467 	if (sc->sc_if.if_flags & IFF_LINK0) {
468 
469 	    /* Ack. the request */
470 	    ppb_wdtr(ppbus, 0x01);
471 
472 	    /* Get the packet length */
473 	    j = clpinbyte(LPMAXSPIN2, ppbus);
474 	    if (j == -1)
475 		goto err;
476 	    len = j;
477 	    j = clpinbyte(LPMAXSPIN2, ppbus);
478 	    if (j == -1)
479 		goto err;
480 	    len = len + (j << 8);
481 	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
482 		goto err;
483 
484 	    bp  = sc->sc_ifbuf;
485 
486 	    while (len--) {
487 	        j = clpinbyte(LPMAXSPIN2, ppbus);
488 	        if (j == -1) {
489 		    goto err;
490 	        }
491 	        *bp++ = j;
492 	    }
493 	    /* Get and ignore checksum */
494 	    j = clpinbyte(LPMAXSPIN2, ppbus);
495 	    if (j == -1) {
496 	        goto err;
497 	    }
498 
499 	    len = bp - sc->sc_ifbuf;
500 	    if (len <= CLPIPHDRLEN)
501 	        goto err;
502 
503 	    sc->sc_iferrs = 0;
504 
505 	    len -= CLPIPHDRLEN;
506 	    sc->sc_if.if_ipackets++;
507 	    sc->sc_if.if_ibytes += len;
508 	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
509 	    if (top) {
510 		if (sc->sc_if.if_bpf)
511 		    lptap(&sc->sc_if, top);
512 		netisr_queue(NETISR_IP, top);
513 	    }
514 	    goto done;
515 	}
516 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
517 	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
518 	    bp  = sc->sc_ifbuf;
519 	    while (len--) {
520 
521 		cl = ppb_rstr(ppbus);
522 		ppb_wdtr(ppbus, 8);
523 
524 		j = LPMAXSPIN2;
525 		while((ppb_rstr(ppbus) & LPIP_SHAKE))
526 		    if(!--j) goto err;
527 
528 		c = ppb_rstr(ppbus);
529 		ppb_wdtr(ppbus, 0);
530 
531 		*bp++= trecvh[cl] | trecvl[c];
532 
533 		j = LPMAXSPIN2;
534 		while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
535 		    if (cl != c &&
536 			(((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
537 			  (c & 0xf8))
538 			goto end;
539 		    if (!--j) goto err;
540 		}
541 	    }
542 
543 	end:
544 	    len = bp - sc->sc_ifbuf;
545 	    if (len <= LPIPHDRLEN)
546 		goto err;
547 
548 	    sc->sc_iferrs = 0;
549 
550 	    len -= LPIPHDRLEN;
551 	    sc->sc_if.if_ipackets++;
552 	    sc->sc_if.if_ibytes += len;
553 	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
554 	    if (top) {
555 		if (sc->sc_if.if_bpf)
556 		    lptap(&sc->sc_if, top);
557 		netisr_queue(NETISR_IP, top);
558 	    }
559 	}
560 	goto done;
561 
562     err:
563 	ppb_wdtr(ppbus, 0);
564 	lprintf("R");
565 	sc->sc_if.if_ierrors++;
566 	sc->sc_iferrs++;
567 
568 	/*
569 	 * We are not able to send receive anything for now,
570 	 * so stop wasting our time
571 	 */
572 	if (sc->sc_iferrs > LPMAXERRS) {
573 	    printf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
574 	    ppb_wctr(ppbus, 0x00);
575 	    sc->sc_if.if_flags &= ~IFF_RUNNING;
576 	    sc->sc_iferrs=0;
577 	}
578 
579     done:
580 	splx(s);
581 	return;
582 }
583 
584 static __inline int
585 lpoutbyte (u_char byte, int spin, device_t ppbus)
586 {
587     ppb_wdtr(ppbus, txmith[byte]);
588     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
589 	if (--spin == 0)
590 		return 1;
591     ppb_wdtr(ppbus, txmitl[byte]);
592     while (ppb_rstr(ppbus) & LPIP_SHAKE)
593 	if (--spin == 0)
594 		return 1;
595     return 0;
596 }
597 
598 static int
599 lpoutput (struct ifnet *ifp, struct mbuf *m,
600 	  struct sockaddr *dst, struct rtentry *rt)
601 {
602     device_t dev = UNITODEVICE(ifp->if_dunit);
603     device_t ppbus = device_get_parent(dev);
604     int s, err;
605     struct mbuf *mm;
606     u_char *cp = "\0\0";
607     u_char chksum = 0;
608     int count = 0;
609     int i, len, spin;
610 
611     /* We need a sensible value if we abort */
612     cp++;
613     ifp->if_flags |= IFF_RUNNING;
614 
615     err = 1;			/* assume we're aborting because of an error */
616 
617     s = splhigh();
618 
619     /* Suspend (on laptops) or receive-errors might have taken us offline */
620     ppb_wctr(ppbus, IRQENABLE);
621 
622     if (ifp->if_flags & IFF_LINK0) {
623 
624 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
625 	    lprintf("&");
626 	    lp_intr(dev);
627 	}
628 
629 	/* Alert other end to pending packet */
630 	spin = LPMAXSPIN1;
631 	ppb_wdtr(ppbus, 0x08);
632 	while ((ppb_rstr(ppbus) & 0x08) == 0)
633 		if (--spin == 0) {
634 			goto nend;
635 		}
636 
637 	/* Calculate length of packet, then send that */
638 
639 	count += 14;		/* Ethernet header len */
640 
641 	mm = m;
642 	for (mm = m; mm; mm = mm->m_next) {
643 		count += mm->m_len;
644 	}
645 	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
646 		goto nend;
647 	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
648 		goto nend;
649 
650 	/* Send dummy ethernet header */
651 	for (i = 0; i < 12; i++) {
652 		if (clpoutbyte(i, LPMAXSPIN1, ppbus))
653 			goto nend;
654 		chksum += i;
655 	}
656 
657 	if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
658 		goto nend;
659 	if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
660 		goto nend;
661 	chksum += 0x08 + 0x00;		/* Add into checksum */
662 
663 	mm = m;
664 	do {
665 		cp = mtod(mm, u_char *);
666 		len = mm->m_len;
667 		while (len--) {
668 			chksum += *cp;
669 			if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
670 				goto nend;
671 		}
672 	} while ((mm = mm->m_next));
673 
674 	/* Send checksum */
675 	if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
676 		goto nend;
677 
678 	/* Go quiescent */
679 	ppb_wdtr(ppbus, 0);
680 
681 	err = 0;			/* No errors */
682 
683 	nend:
684 	if (err)  {				/* if we didn't timeout... */
685 		ifp->if_oerrors++;
686 		lprintf("X");
687 	} else {
688 		ifp->if_opackets++;
689 		ifp->if_obytes += m->m_pkthdr.len;
690 		if (ifp->if_bpf)
691 		    lptap(ifp, m);
692 	}
693 
694 	m_freem(m);
695 
696 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
697 		lprintf("^");
698 		lp_intr(dev);
699 	}
700 	(void) splx(s);
701 	return 0;
702     }
703 
704     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
705         lprintf("&");
706         lp_intr(dev);
707     }
708 
709     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
710         goto end;
711     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
712         goto end;
713 
714     mm = m;
715     do {
716         cp = mtod(mm,u_char *);
717 	len = mm->m_len;
718         while (len--)
719 	    if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
720 	        goto end;
721     } while ((mm = mm->m_next));
722 
723     err = 0;				/* no errors were encountered */
724 
725     end:
726     --cp;
727     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
728 
729     if (err)  {				/* if we didn't timeout... */
730 	ifp->if_oerrors++;
731         lprintf("X");
732     } else {
733 	ifp->if_opackets++;
734 	ifp->if_obytes += m->m_pkthdr.len;
735 	if (ifp->if_bpf)
736 	    lptap(ifp, m);
737     }
738 
739     m_freem(m);
740 
741     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
742 	lprintf("^");
743 	lp_intr(dev);
744     }
745 
746     (void) splx(s);
747     return 0;
748 }
749 
750 static device_method_t lp_methods[] = {
751   	/* device interface */
752 	DEVMETHOD(device_identify,	lp_identify),
753 	DEVMETHOD(device_probe,		lp_probe),
754 	DEVMETHOD(device_attach,	lp_attach),
755 
756 	{ 0, 0 }
757 };
758 
759 static driver_t lp_driver = {
760   "plip",
761   lp_methods,
762   sizeof(struct lp_data),
763 };
764 
765 DRIVER_MODULE(plip, ppbus, lp_driver, lp_devclass, 0, 0);
766