xref: /dragonfly/sys/dev/netif/plip/if_plip.c (revision 8a7bdfea)
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 1.20 2008/01/06 16:55:50 swildner 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/rman.h>
94 #include <sys/thread2.h>
95 
96 #include <machine/clock.h>
97 
98 #include <net/if.h>
99 #include <net/ifq_var.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) kprintf
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 /*
186  * lpprobe()
187  */
188 static int
189 lp_probe(device_t dev)
190 {
191 	device_t ppbus = device_get_parent(dev);
192 	struct lp_data *lp;
193 	int zero = 0;
194 	uintptr_t irq;
195 
196 	lp = DEVTOSOFTC(dev);
197 
198 	/* retrieve the ppbus irq */
199 	BUS_READ_IVAR(ppbus, dev, PPBUS_IVAR_IRQ, &irq);
200 
201 	/* if we haven't interrupts, the probe fails */
202 	if (irq == -1) {
203 		device_printf(dev, "not an interrupt driven port, failed.\n");
204 		return (ENXIO);
205 	}
206 
207 	/* reserve the interrupt resource, expecting irq is available to continue */
208 	lp->res_irq = bus_alloc_resource(dev, SYS_RES_IRQ, &zero, irq, irq, 1,
209 					 RF_SHAREABLE);
210 	if (lp->res_irq == 0) {
211 		device_printf(dev, "cannot reserve interrupt, failed.\n");
212 		return (ENXIO);
213 	}
214 
215 	/*
216 	 * lp dependent initialisation.
217 	 */
218 	lp->lp_unit = device_get_unit(dev);
219 
220 	device_set_desc(dev, "PLIP network interface");
221 
222 	return (0);
223 }
224 
225 static int
226 lp_attach (device_t dev)
227 {
228 	struct lp_data *lp = DEVTOSOFTC(dev);
229 	struct ifnet *ifp = &lp->sc_if;
230 
231 	ifp->if_softc = lp;
232 	if_initname(ifp, "lp", device_get_unit(dev));
233 	ifp->if_mtu = LPMTU;
234 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
235 	ifp->if_ioctl = lpioctl;
236 	ifp->if_output = lpoutput;
237 	ifp->if_type = IFT_PARA;
238 	ifp->if_hdrlen = 0;
239 	ifp->if_addrlen = 0;
240 	ifq_set_maxlen(&ifp->if_snd, IFQ_MAXLEN);
241 	if_attach(ifp, NULL);
242 
243 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
244 
245 	return (0);
246 }
247 /*
248  * Build the translation tables for the LPIP (BSD unix) protocol.
249  * We don't want to calculate these nasties in our tight loop, so we
250  * precalculate them when we initialize.
251  */
252 static int
253 lpinittables (void)
254 {
255     int i;
256 
257     if (!txmith)
258 	txmith = kmalloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
259 
260     if (!ctxmith)
261 	ctxmith = kmalloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
262 
263     for (i=0; i < LPIPTBLSIZE; i++) {
264 	ctxmith[i] = (i & 0xF0) >> 4;
265 	ctxmitl[i] = 0x10 | (i & 0x0F);
266 	ctrecvh[i] = (i & 0x78) << 1;
267 	ctrecvl[i] = (i & 0x78) >> 3;
268     }
269 
270     for (i=0; i < LPIPTBLSIZE; i++) {
271 	txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
272 	txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
273 	trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
274 	trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
275     }
276 
277     return 0;
278 }
279 
280 /*
281  * Process an ioctl request.
282  */
283 
284 static int
285 lpioctl (struct ifnet *ifp, u_long cmd, caddr_t data, struct ucred *cr)
286 {
287     device_t dev = UNITODEVICE(ifp->if_dunit);
288     device_t ppbus = device_get_parent(dev);
289     struct lp_data *sc = DEVTOSOFTC(dev);
290     struct ifaddr *ifa = (struct ifaddr *)data;
291     struct ifreq *ifr = (struct ifreq *)data;
292     u_char *ptr;
293     void *ih;
294     int error;
295 
296     switch (cmd) {
297 
298     case SIOCSIFDSTADDR:
299     case SIOCAIFADDR:
300     case SIOCSIFADDR:
301 	if (ifa->ifa_addr->sa_family != AF_INET)
302 	    return EAFNOSUPPORT;
303 
304 	ifp->if_flags |= IFF_UP;
305 	/* FALLTHROUGH */
306     case SIOCSIFFLAGS:
307 	if ((!(ifp->if_flags & IFF_UP)) && (ifp->if_flags & IFF_RUNNING)) {
308 
309 	    ppb_wctr(ppbus, 0x00);
310 	    ifp->if_flags &= ~IFF_RUNNING;
311 
312 	    /* IFF_UP is not set, try to release the bus anyway */
313 	    ppb_release_bus(ppbus, dev);
314 	    break;
315 	}
316 	if (((ifp->if_flags & IFF_UP)) && (!(ifp->if_flags & IFF_RUNNING))) {
317 
318 	    /* XXX
319 	     * Should the request be interruptible?
320 	     */
321 	    if ((error = ppb_request_bus(ppbus, dev, PPB_WAIT|PPB_INTR)))
322 		return (error);
323 
324 	    /* Now IFF_UP means that we own the bus */
325 
326 	    ppb_set_mode(ppbus, PPB_COMPATIBLE);
327 
328 	    if (lpinittables()) {
329 		ppb_release_bus(ppbus, dev);
330 		return ENOBUFS;
331 	    }
332 
333 	    sc->sc_ifbuf = kmalloc(sc->sc_if.if_mtu + MLPIPHDRLEN,
334 				  M_DEVBUF, M_WAITOK);
335 
336 	    /* attach our interrupt handler, later detached when the bus is released */
337 	    error = BUS_SETUP_INTR(ppbus, dev, sc->res_irq, 0,
338 				   lp_intr, dev, &ih, NULL);
339 	    if (error) {
340 		ppb_release_bus(ppbus, dev);
341 		return (error);
342 	    }
343 
344 	    ppb_wctr(ppbus, IRQENABLE);
345 	    ifp->if_flags |= IFF_RUNNING;
346 	}
347 	break;
348 
349     case SIOCSIFMTU:
350 	ptr = sc->sc_ifbuf;
351 	sc->sc_ifbuf = kmalloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
352 	if (ptr)
353 	    kfree(ptr,M_DEVBUF);
354 	sc->sc_if.if_mtu = ifr->ifr_mtu;
355 	break;
356 
357     case SIOCGIFMTU:
358 	ifr->ifr_mtu = sc->sc_if.if_mtu;
359 	break;
360 
361     case SIOCADDMULTI:
362     case SIOCDELMULTI:
363 	if (ifr == 0) {
364 	    return EAFNOSUPPORT;		/* XXX */
365 	}
366 	switch (ifr->ifr_addr.sa_family) {
367 
368 	case AF_INET:
369 	    break;
370 
371 	default:
372 	    return EAFNOSUPPORT;
373 	}
374 	break;
375 
376     case SIOCGIFMEDIA:
377 	/*
378 	 * No ifmedia support at this stage; maybe use it
379 	 * in future for eg. protocol selection.
380 	 */
381 	return EINVAL;
382 
383     default:
384 	lprintf("LP:ioctl(0x%lx)\n", cmd);
385 	return EINVAL;
386     }
387     return 0;
388 }
389 
390 static __inline int
391 clpoutbyte (u_char byte, int spin, device_t ppbus)
392 {
393 	ppb_wdtr(ppbus, ctxmitl[byte]);
394 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
395 		if (--spin == 0) {
396 			return 1;
397 		}
398 	ppb_wdtr(ppbus, ctxmith[byte]);
399 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
400 		if (--spin == 0) {
401 			return 1;
402 		}
403 	return 0;
404 }
405 
406 static __inline int
407 clpinbyte (int spin, device_t ppbus)
408 {
409 	u_char c, cl;
410 
411 	while((ppb_rstr(ppbus) & CLPIP_SHAKE))
412 	    if(!--spin) {
413 		return -1;
414 	    }
415 	cl = ppb_rstr(ppbus);
416 	ppb_wdtr(ppbus, 0x10);
417 
418 	while(!(ppb_rstr(ppbus) & CLPIP_SHAKE))
419 	    if(!--spin) {
420 		return -1;
421 	    }
422 	c = ppb_rstr(ppbus);
423 	ppb_wdtr(ppbus, 0x00);
424 
425 	return (ctrecvl[cl] | ctrecvh[c]);
426 }
427 
428 static void
429 lptap(struct ifnet *ifp, struct mbuf *m)
430 {
431 	/*
432 	 * We need to prepend the address family as a four byte field.
433 	 */
434 	static const uint32_t af = AF_INET;
435 
436 	if (ifp->if_bpf)
437 		bpf_ptap(ifp->if_bpf, m, &af, sizeof(af));
438 }
439 
440 static void
441 lp_intr (void *arg)
442 {
443 	device_t dev = (device_t)arg;
444         device_t ppbus = device_get_parent(dev);
445 	struct lp_data *sc = DEVTOSOFTC(dev);
446 	int len, j;
447 	u_char *bp;
448 	u_char c, cl;
449 	struct mbuf *top;
450 
451 	crit_enter();
452 
453 	if (sc->sc_if.if_flags & IFF_LINK0) {
454 
455 	    /* Ack. the request */
456 	    ppb_wdtr(ppbus, 0x01);
457 
458 	    /* Get the packet length */
459 	    j = clpinbyte(LPMAXSPIN2, ppbus);
460 	    if (j == -1)
461 		goto err;
462 	    len = j;
463 	    j = clpinbyte(LPMAXSPIN2, ppbus);
464 	    if (j == -1)
465 		goto err;
466 	    len = len + (j << 8);
467 	    if (len > sc->sc_if.if_mtu + MLPIPHDRLEN)
468 		goto err;
469 
470 	    bp  = sc->sc_ifbuf;
471 
472 	    while (len--) {
473 	        j = clpinbyte(LPMAXSPIN2, ppbus);
474 	        if (j == -1) {
475 		    goto err;
476 	        }
477 	        *bp++ = j;
478 	    }
479 	    /* Get and ignore checksum */
480 	    j = clpinbyte(LPMAXSPIN2, ppbus);
481 	    if (j == -1) {
482 	        goto err;
483 	    }
484 
485 	    len = bp - sc->sc_ifbuf;
486 	    if (len <= CLPIPHDRLEN)
487 	        goto err;
488 
489 	    sc->sc_iferrs = 0;
490 
491 	    len -= CLPIPHDRLEN;
492 	    sc->sc_if.if_ipackets++;
493 	    sc->sc_if.if_ibytes += len;
494 	    top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, &sc->sc_if, 0);
495 	    if (top) {
496 		if (sc->sc_if.if_bpf)
497 		    lptap(&sc->sc_if, top);
498 		netisr_queue(NETISR_IP, top);
499 	    }
500 	    goto done;
501 	}
502 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
503 	    len = sc->sc_if.if_mtu + LPIPHDRLEN;
504 	    bp  = sc->sc_ifbuf;
505 	    while (len--) {
506 
507 		cl = ppb_rstr(ppbus);
508 		ppb_wdtr(ppbus, 8);
509 
510 		j = LPMAXSPIN2;
511 		while((ppb_rstr(ppbus) & LPIP_SHAKE))
512 		    if(!--j) goto err;
513 
514 		c = ppb_rstr(ppbus);
515 		ppb_wdtr(ppbus, 0);
516 
517 		*bp++= trecvh[cl] | trecvl[c];
518 
519 		j = LPMAXSPIN2;
520 		while (!((cl=ppb_rstr(ppbus)) & LPIP_SHAKE)) {
521 		    if (cl != c &&
522 			(((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
523 			  (c & 0xf8))
524 			goto end;
525 		    if (!--j) goto err;
526 		}
527 	    }
528 
529 	end:
530 	    len = bp - sc->sc_ifbuf;
531 	    if (len <= LPIPHDRLEN)
532 		goto err;
533 
534 	    sc->sc_iferrs = 0;
535 
536 	    len -= LPIPHDRLEN;
537 	    sc->sc_if.if_ipackets++;
538 	    sc->sc_if.if_ibytes += len;
539 	    top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, &sc->sc_if, 0);
540 	    if (top) {
541 		if (sc->sc_if.if_bpf)
542 		    lptap(&sc->sc_if, top);
543 		netisr_queue(NETISR_IP, top);
544 	    }
545 	}
546 	goto done;
547 
548     err:
549 	ppb_wdtr(ppbus, 0);
550 	lprintf("R");
551 	sc->sc_if.if_ierrors++;
552 	sc->sc_iferrs++;
553 
554 	/*
555 	 * We are not able to send receive anything for now,
556 	 * so stop wasting our time
557 	 */
558 	if (sc->sc_iferrs > LPMAXERRS) {
559 	    kprintf("lp%d: Too many errors, Going off-line.\n", device_get_unit(dev));
560 	    ppb_wctr(ppbus, 0x00);
561 	    sc->sc_if.if_flags &= ~IFF_RUNNING;
562 	    sc->sc_iferrs=0;
563 	}
564 
565     done:
566 	crit_exit();
567 	return;
568 }
569 
570 static __inline int
571 lpoutbyte (u_char byte, int spin, device_t ppbus)
572 {
573     ppb_wdtr(ppbus, txmith[byte]);
574     while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
575 	if (--spin == 0)
576 		return 1;
577     ppb_wdtr(ppbus, txmitl[byte]);
578     while (ppb_rstr(ppbus) & LPIP_SHAKE)
579 	if (--spin == 0)
580 		return 1;
581     return 0;
582 }
583 
584 static int
585 lpoutput (struct ifnet *ifp, struct mbuf *m,
586 	  struct sockaddr *dst, struct rtentry *rt)
587 {
588     device_t dev = UNITODEVICE(ifp->if_dunit);
589     device_t ppbus = device_get_parent(dev);
590     int err;
591     struct mbuf *mm;
592     u_char *cp = "\0\0";
593     u_char chksum = 0;
594     int count = 0;
595     int i, len, spin;
596 
597     /* We need a sensible value if we abort */
598     cp++;
599     ifp->if_flags |= IFF_RUNNING;
600 
601     err = 1;			/* assume we're aborting because of an error */
602 
603     crit_enter();
604 
605     /* Suspend (on laptops) or receive-errors might have taken us offline */
606     ppb_wctr(ppbus, IRQENABLE);
607 
608     if (ifp->if_flags & IFF_LINK0) {
609 
610 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
611 	    lprintf("&");
612 	    lp_intr(dev);
613 	}
614 
615 	/* Alert other end to pending packet */
616 	spin = LPMAXSPIN1;
617 	ppb_wdtr(ppbus, 0x08);
618 	while ((ppb_rstr(ppbus) & 0x08) == 0)
619 		if (--spin == 0) {
620 			goto nend;
621 		}
622 
623 	/* Calculate length of packet, then send that */
624 
625 	count += 14;		/* Ethernet header len */
626 
627 	mm = m;
628 	for (mm = m; mm; mm = mm->m_next) {
629 		count += mm->m_len;
630 	}
631 	if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
632 		goto nend;
633 	if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
634 		goto nend;
635 
636 	/* Send dummy ethernet header */
637 	for (i = 0; i < 12; i++) {
638 		if (clpoutbyte(i, LPMAXSPIN1, ppbus))
639 			goto nend;
640 		chksum += i;
641 	}
642 
643 	if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
644 		goto nend;
645 	if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
646 		goto nend;
647 	chksum += 0x08 + 0x00;		/* Add into checksum */
648 
649 	mm = m;
650 	do {
651 		cp = mtod(mm, u_char *);
652 		len = mm->m_len;
653 		while (len--) {
654 			chksum += *cp;
655 			if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
656 				goto nend;
657 		}
658 	} while ((mm = mm->m_next));
659 
660 	/* Send checksum */
661 	if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
662 		goto nend;
663 
664 	/* Go quiescent */
665 	ppb_wdtr(ppbus, 0);
666 
667 	err = 0;			/* No errors */
668 
669 	nend:
670 	if (err)  {				/* if we didn't timeout... */
671 		ifp->if_oerrors++;
672 		lprintf("X");
673 	} else {
674 		ifp->if_opackets++;
675 		ifp->if_obytes += m->m_pkthdr.len;
676 		if (ifp->if_bpf)
677 		    lptap(ifp, m);
678 	}
679 
680 	m_freem(m);
681 
682 	if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
683 		lprintf("^");
684 		lp_intr(dev);
685 	}
686 	crit_exit();
687 	return 0;
688     }
689 
690     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
691         lprintf("&");
692         lp_intr(dev);
693     }
694 
695     if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
696         goto end;
697     if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
698         goto end;
699 
700     mm = m;
701     do {
702         cp = mtod(mm,u_char *);
703 	len = mm->m_len;
704         while (len--)
705 	    if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
706 	        goto end;
707     } while ((mm = mm->m_next));
708 
709     err = 0;				/* no errors were encountered */
710 
711     end:
712     --cp;
713     ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
714 
715     if (err)  {				/* if we didn't timeout... */
716 	ifp->if_oerrors++;
717         lprintf("X");
718     } else {
719 	ifp->if_opackets++;
720 	ifp->if_obytes += m->m_pkthdr.len;
721 	if (ifp->if_bpf)
722 	    lptap(ifp, m);
723     }
724 
725     m_freem(m);
726 
727     if (ppb_rstr(ppbus) & LPIP_SHAKE) {
728 	lprintf("^");
729 	lp_intr(dev);
730     }
731 
732     crit_exit();
733     return 0;
734 }
735 
736 /*
737  * Because plip is a static device that always exists under any attached
738  * ppbus device, and not scanned by the ppbus device, we need an identify
739  * function to install the device.
740  */
741 static device_method_t lp_methods[] = {
742   	/* device interface */
743 	DEVMETHOD(device_identify,	bus_generic_identify),
744 	DEVMETHOD(device_probe,		lp_probe),
745 	DEVMETHOD(device_attach,	lp_attach),
746 
747 	{ 0, 0 }
748 };
749 
750 static driver_t lp_driver = {
751   "plip",
752   lp_methods,
753   sizeof(struct lp_data),
754 };
755 
756 DECLARE_DUMMY_MODULE(if_plip);
757 DRIVER_MODULE(if_plip, ppbus, lp_driver, lp_devclass, 0, 0);
758 
759