xref: /freebsd/sys/dev/ppbus/if_plip.c (revision d4ae33f0721c1b170fe37d97e395228ffcfb3f80)
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_var.h>
101 #include <net/if_types.h>
102 #include <net/netisr.h>
103 #include <net/route.h>
104 
105 #include <netinet/in.h>
106 #include <netinet/in_var.h>
107 
108 #include <net/bpf.h>
109 
110 #include <dev/ppbus/ppbconf.h>
111 #include "ppbus_if.h"
112 #include <dev/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 	struct  ifnet	*sc_ifp;
152 	device_t	sc_dev;
153 	u_char		*sc_ifbuf;
154 	int		sc_iferrs;
155 
156 	struct resource *res_irq;
157 	void		*sc_intr_cookie;
158 };
159 
160 static struct mtx lp_tables_lock;
161 MTX_SYSINIT(lp_tables, &lp_tables_lock, "plip tables", MTX_DEF);
162 
163 /* Tables for the lp# interface */
164 static u_char *txmith;
165 #define	txmitl (txmith + (1 * LPIPTBLSIZE))
166 #define	trecvh (txmith + (2 * LPIPTBLSIZE))
167 #define	trecvl (txmith + (3 * LPIPTBLSIZE))
168 
169 static u_char *ctxmith;
170 #define	ctxmitl (ctxmith + (1 * LPIPTBLSIZE))
171 #define	ctrecvh (ctxmith + (2 * LPIPTBLSIZE))
172 #define	ctrecvl (ctxmith + (3 * LPIPTBLSIZE))
173 
174 /* Functions for the lp# interface */
175 static int lpinittables(void);
176 static int lpioctl(struct ifnet *, u_long, caddr_t);
177 static int lpoutput(struct ifnet *, struct mbuf *, const struct sockaddr *,
178        struct route *);
179 static void lpstop(struct lp_data *);
180 static void lp_intr(void *);
181 static int lp_module_handler(module_t, int, void *);
182 
183 #define	DEVTOSOFTC(dev) \
184 	((struct lp_data *)device_get_softc(dev))
185 
186 static devclass_t lp_devclass;
187 
188 static int
189 lp_module_handler(module_t mod, int what, void *arg)
190 {
191 
192 	switch (what) {
193 	case MOD_UNLOAD:
194 		mtx_lock(&lp_tables_lock);
195 		if (txmith != NULL) {
196 			free(txmith, M_DEVBUF);
197 			txmith = NULL;
198 		}
199 		if (ctxmith != NULL) {
200 			free(ctxmith, M_DEVBUF);
201 			ctxmith = NULL;
202 		}
203 		mtx_unlock(&lp_tables_lock);
204 		break;
205 	case MOD_LOAD:
206 	case MOD_QUIESCE:
207 		break;
208 	default:
209 		return (EOPNOTSUPP);
210 	}
211 	return (0);
212 }
213 
214 static void
215 lp_identify(driver_t *driver, device_t parent)
216 {
217 	device_t dev;
218 
219 	dev = device_find_child(parent, "plip", -1);
220 	if (!dev)
221 		BUS_ADD_CHILD(parent, 0, "plip", -1);
222 }
223 
224 static int
225 lp_probe(device_t dev)
226 {
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;
238 	int error, rid = 0;
239 
240 	lp->sc_dev = dev;
241 
242 	/*
243 	 * Reserve the interrupt resource.  If we don't have one, the
244 	 * attach fails.
245 	 */
246 	lp->res_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
247 	    RF_SHAREABLE);
248 	if (lp->res_irq == 0) {
249 		device_printf(dev, "cannot reserve interrupt, failed.\n");
250 		return (ENXIO);
251 	}
252 
253 	ifp = lp->sc_ifp = if_alloc(IFT_PARA);
254 	if (ifp == NULL) {
255 		return (ENOSPC);
256 	}
257 
258 	ifp->if_softc = lp;
259 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
260 	ifp->if_mtu = LPMTU;
261 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
262 	ifp->if_ioctl = lpioctl;
263 	ifp->if_output = lpoutput;
264 	ifp->if_hdrlen = 0;
265 	ifp->if_addrlen = 0;
266 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
267 	if_attach(ifp);
268 
269 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
270 
271 	/*
272 	 * Attach our interrupt handler.  It is only called while we
273 	 * own the ppbus.
274 	 */
275 	error = bus_setup_intr(dev, lp->res_irq, INTR_TYPE_NET | INTR_MPSAFE,
276 	    NULL, lp_intr, lp, &lp->sc_intr_cookie);
277 	if (error) {
278 		bpfdetach(ifp);
279 		if_detach(ifp);
280 		bus_release_resource(dev, SYS_RES_IRQ, 0, lp->res_irq);
281 		device_printf(dev, "Unable to register interrupt handler\n");
282 		return (error);
283 	}
284 
285 	return (0);
286 }
287 
288 static int
289 lp_detach(device_t dev)
290 {
291 	struct lp_data *sc = device_get_softc(dev);
292 	device_t ppbus = device_get_parent(dev);
293 
294 	ppb_lock(ppbus);
295 	lpstop(sc);
296 	ppb_unlock(ppbus);
297 	bpfdetach(sc->sc_ifp);
298 	if_detach(sc->sc_ifp);
299 	bus_teardown_intr(dev, sc->res_irq, sc->sc_intr_cookie);
300 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->res_irq);
301 	return (0);
302 }
303 
304 /*
305  * Build the translation tables for the LPIP (BSD unix) protocol.
306  * We don't want to calculate these nasties in our tight loop, so we
307  * precalculate them when we initialize.
308  */
309 static int
310 lpinittables(void)
311 {
312 	int i;
313 
314 	mtx_lock(&lp_tables_lock);
315 	if (txmith == NULL)
316 		txmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
317 
318 	if (txmith == NULL) {
319 		mtx_unlock(&lp_tables_lock);
320 		return (1);
321 	}
322 
323 	if (ctxmith == NULL)
324 		ctxmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
325 
326 	if (ctxmith == NULL) {
327 		mtx_unlock(&lp_tables_lock);
328 		return (1);
329 	}
330 
331 	for (i = 0; i < LPIPTBLSIZE; i++) {
332 		ctxmith[i] = (i & 0xF0) >> 4;
333 		ctxmitl[i] = 0x10 | (i & 0x0F);
334 		ctrecvh[i] = (i & 0x78) << 1;
335 		ctrecvl[i] = (i & 0x78) >> 3;
336 	}
337 
338 	for (i = 0; i < LPIPTBLSIZE; i++) {
339 		txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
340 		txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
341 		trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
342 		trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
343 	}
344 	mtx_unlock(&lp_tables_lock);
345 
346 	return (0);
347 }
348 
349 static void
350 lpstop(struct lp_data *sc)
351 {
352 	device_t ppbus = device_get_parent(sc->sc_dev);
353 
354 	ppb_assert_locked(ppbus);
355 	ppb_wctr(ppbus, 0x00);
356 	sc->sc_ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
357 	free(sc->sc_ifbuf, M_DEVBUF);
358 	sc->sc_ifbuf = NULL;
359 
360 	/* IFF_UP is not set, try to release the bus anyway */
361 	ppb_release_bus(ppbus, sc->sc_dev);
362 }
363 
364 static int
365 lpinit_locked(struct ifnet *ifp)
366 {
367 	struct lp_data *sc = ifp->if_softc;
368 	device_t dev = sc->sc_dev;
369 	device_t ppbus = device_get_parent(dev);
370 	int error;
371 
372 	ppb_assert_locked(ppbus);
373 	error = ppb_request_bus(ppbus, dev, PPB_DONTWAIT);
374 	if (error)
375 		return (error);
376 
377 	/* Now IFF_UP means that we own the bus */
378 	ppb_set_mode(ppbus, PPB_COMPATIBLE);
379 
380 	if (lpinittables()) {
381 		ppb_release_bus(ppbus, dev);
382 		return (ENOBUFS);
383 	}
384 
385 	sc->sc_ifbuf = malloc(sc->sc_ifp->if_mtu + MLPIPHDRLEN,
386 	    M_DEVBUF, M_NOWAIT);
387 	if (sc->sc_ifbuf == NULL) {
388 		ppb_release_bus(ppbus, dev);
389 		return (ENOBUFS);
390 	}
391 
392 	ppb_wctr(ppbus, IRQENABLE);
393 
394 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
395 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
396 	return (0);
397 }
398 
399 /*
400  * Process an ioctl request.
401  */
402 static int
403 lpioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
404 {
405 	struct lp_data *sc = ifp->if_softc;
406 	device_t dev = sc->sc_dev;
407 	device_t ppbus = device_get_parent(dev);
408 	struct ifaddr *ifa = (struct ifaddr *)data;
409 	struct ifreq *ifr = (struct ifreq *)data;
410 	u_char *ptr;
411 	int error;
412 
413 	switch (cmd) {
414 	case SIOCAIFADDR:
415 	case SIOCSIFADDR:
416 		if (ifa->ifa_addr->sa_family != AF_INET)
417 			return (EAFNOSUPPORT);
418 
419 		ifp->if_flags |= IFF_UP;
420 		/* FALLTHROUGH */
421 	case SIOCSIFFLAGS:
422 		error = 0;
423 		ppb_lock(ppbus);
424 		if ((!(ifp->if_flags & IFF_UP)) &&
425 		    (ifp->if_drv_flags & IFF_DRV_RUNNING))
426 			lpstop(sc);
427 		else if (((ifp->if_flags & IFF_UP)) &&
428 		    (!(ifp->if_drv_flags & IFF_DRV_RUNNING)))
429 			error = lpinit_locked(ifp);
430 		ppb_unlock(ppbus);
431 		return (error);
432 
433 	case SIOCSIFMTU:
434 		ppb_lock(ppbus);
435 		if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
436 			ptr = malloc(ifr->ifr_mtu + MLPIPHDRLEN, M_DEVBUF,
437 			    M_NOWAIT);
438 			if (ptr == NULL) {
439 				ppb_unlock(ppbus);
440 				return (ENOBUFS);
441 			}
442 			if (sc->sc_ifbuf)
443 				free(sc->sc_ifbuf, M_DEVBUF);
444 			sc->sc_ifbuf = ptr;
445 		}
446 		sc->sc_ifp->if_mtu = ifr->ifr_mtu;
447 		ppb_unlock(ppbus);
448 		break;
449 
450 	case SIOCGIFMTU:
451 		ifr->ifr_mtu = sc->sc_ifp->if_mtu;
452 		break;
453 
454 	case SIOCADDMULTI:
455 	case SIOCDELMULTI:
456 		if (ifr == 0) {
457 			return (EAFNOSUPPORT);		/* XXX */
458 		}
459 		switch (ifr->ifr_addr.sa_family) {
460 		case AF_INET:
461 			break;
462 		default:
463 			return (EAFNOSUPPORT);
464 		}
465 		break;
466 
467 	case SIOCGIFMEDIA:
468 		/*
469 		 * No ifmedia support at this stage; maybe use it
470 		 * in future for eg. protocol selection.
471 		 */
472 		return (EINVAL);
473 
474 	default:
475 		lprintf("LP:ioctl(0x%lx)\n", cmd);
476 		return (EINVAL);
477 	}
478 	return (0);
479 }
480 
481 static __inline int
482 clpoutbyte(u_char byte, int spin, device_t ppbus)
483 {
484 
485 	ppb_wdtr(ppbus, ctxmitl[byte]);
486 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
487 		if (--spin == 0) {
488 			return (1);
489 		}
490 	ppb_wdtr(ppbus, ctxmith[byte]);
491 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
492 		if (--spin == 0) {
493 			return (1);
494 		}
495 	return (0);
496 }
497 
498 static __inline int
499 clpinbyte(int spin, device_t ppbus)
500 {
501 	u_char c, cl;
502 
503 	while ((ppb_rstr(ppbus) & CLPIP_SHAKE))
504 		if (!--spin) {
505 			return (-1);
506 		}
507 	cl = ppb_rstr(ppbus);
508 	ppb_wdtr(ppbus, 0x10);
509 
510 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
511 		if (!--spin) {
512 			return (-1);
513 		}
514 	c = ppb_rstr(ppbus);
515 	ppb_wdtr(ppbus, 0x00);
516 
517 	return (ctrecvl[cl] | ctrecvh[c]);
518 }
519 
520 static void
521 lptap(struct ifnet *ifp, struct mbuf *m)
522 {
523 	u_int32_t af = AF_INET;
524 
525 	bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
526 }
527 
528 static void
529 lp_intr(void *arg)
530 {
531 	struct lp_data *sc = arg;
532 	device_t ppbus = device_get_parent(sc->sc_dev);
533 	int len, j;
534 	u_char *bp;
535 	u_char c, cl;
536 	struct mbuf *top;
537 
538 	ppb_assert_locked(ppbus);
539 	if (sc->sc_ifp->if_flags & IFF_LINK0) {
540 
541 		/* Ack. the request */
542 		ppb_wdtr(ppbus, 0x01);
543 
544 		/* Get the packet length */
545 		j = clpinbyte(LPMAXSPIN2, ppbus);
546 		if (j == -1)
547 			goto err;
548 		len = j;
549 		j = clpinbyte(LPMAXSPIN2, ppbus);
550 		if (j == -1)
551 			goto err;
552 		len = len + (j << 8);
553 		if (len > sc->sc_ifp->if_mtu + MLPIPHDRLEN)
554 			goto err;
555 
556 		bp = sc->sc_ifbuf;
557 
558 		while (len--) {
559 			j = clpinbyte(LPMAXSPIN2, ppbus);
560 			if (j == -1) {
561 				goto err;
562 			}
563 			*bp++ = j;
564 		}
565 
566 		/* Get and ignore checksum */
567 		j = clpinbyte(LPMAXSPIN2, ppbus);
568 		if (j == -1) {
569 			goto err;
570 		}
571 
572 		len = bp - sc->sc_ifbuf;
573 		if (len <= CLPIPHDRLEN)
574 			goto err;
575 
576 		sc->sc_iferrs = 0;
577 
578 		len -= CLPIPHDRLEN;
579 		sc->sc_ifp->if_ipackets++;
580 		sc->sc_ifp->if_ibytes += len;
581 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, sc->sc_ifp,
582 		    0);
583 		if (top) {
584 			ppb_unlock(ppbus);
585 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
586 				lptap(sc->sc_ifp, top);
587 
588 			M_SETFIB(top, sc->sc_ifp->if_fib);
589 
590 			/* mbuf is free'd on failure. */
591 			netisr_queue(NETISR_IP, top);
592 			ppb_lock(ppbus);
593 		}
594 		return;
595 	}
596 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
597 		len = sc->sc_ifp->if_mtu + LPIPHDRLEN;
598 		bp  = sc->sc_ifbuf;
599 		while (len--) {
600 
601 			cl = ppb_rstr(ppbus);
602 			ppb_wdtr(ppbus, 8);
603 
604 			j = LPMAXSPIN2;
605 			while ((ppb_rstr(ppbus) & LPIP_SHAKE))
606 				if (!--j)
607 					goto err;
608 
609 			c = ppb_rstr(ppbus);
610 			ppb_wdtr(ppbus, 0);
611 
612 			*bp++= trecvh[cl] | trecvl[c];
613 
614 			j = LPMAXSPIN2;
615 			while (!((cl = ppb_rstr(ppbus)) & LPIP_SHAKE)) {
616 				if (cl != c &&
617 				    (((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
618 				    (c & 0xf8))
619 					goto end;
620 				if (!--j)
621 					goto err;
622 			}
623 		}
624 
625 	end:
626 		len = bp - sc->sc_ifbuf;
627 		if (len <= LPIPHDRLEN)
628 			goto err;
629 
630 		sc->sc_iferrs = 0;
631 
632 		len -= LPIPHDRLEN;
633 		sc->sc_ifp->if_ipackets++;
634 		sc->sc_ifp->if_ibytes += len;
635 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, sc->sc_ifp,
636 		    0);
637 		if (top) {
638 			ppb_unlock(ppbus);
639 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
640 				lptap(sc->sc_ifp, top);
641 
642 			M_SETFIB(top, sc->sc_ifp->if_fib);
643 
644 			/* mbuf is free'd on failure. */
645 			netisr_queue(NETISR_IP, top);
646 			ppb_lock(ppbus);
647 		}
648 	}
649 	return;
650 
651 err:
652 	ppb_wdtr(ppbus, 0);
653 	lprintf("R");
654 	sc->sc_ifp->if_ierrors++;
655 	sc->sc_iferrs++;
656 
657 	/*
658 	 * We are not able to send receive anything for now,
659 	 * so stop wasting our time
660 	 */
661 	if (sc->sc_iferrs > LPMAXERRS) {
662 		if_printf(sc->sc_ifp, "Too many errors, Going off-line.\n");
663 		ppb_wctr(ppbus, 0x00);
664 		sc->sc_ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
665 		sc->sc_iferrs = 0;
666 	}
667 }
668 
669 static __inline int
670 lpoutbyte(u_char byte, int spin, device_t ppbus)
671 {
672 
673 	ppb_wdtr(ppbus, txmith[byte]);
674 	while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
675 		if (--spin == 0)
676 			return (1);
677 	ppb_wdtr(ppbus, txmitl[byte]);
678 	while (ppb_rstr(ppbus) & LPIP_SHAKE)
679 		if (--spin == 0)
680 			return (1);
681 	return (0);
682 }
683 
684 static int
685 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
686     struct route *ro)
687 {
688 	struct lp_data *sc = ifp->if_softc;
689 	device_t dev = sc->sc_dev;
690 	device_t ppbus = device_get_parent(dev);
691 	int err;
692 	struct mbuf *mm;
693 	u_char *cp = "\0\0";
694 	u_char chksum = 0;
695 	int count = 0;
696 	int i, len, spin;
697 
698 	/* We need a sensible value if we abort */
699 	cp++;
700 	ppb_lock(ppbus);
701 	ifp->if_drv_flags |= IFF_DRV_OACTIVE;
702 
703 	err = 1;		/* assume we're aborting because of an error */
704 
705 	/* Suspend (on laptops) or receive-errors might have taken us offline */
706 	ppb_wctr(ppbus, IRQENABLE);
707 
708 	if (ifp->if_flags & IFF_LINK0) {
709 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
710 			lprintf("&");
711 			lp_intr(sc);
712 		}
713 
714 		/* Alert other end to pending packet */
715 		spin = LPMAXSPIN1;
716 		ppb_wdtr(ppbus, 0x08);
717 		while ((ppb_rstr(ppbus) & 0x08) == 0)
718 			if (--spin == 0) {
719 				goto nend;
720 			}
721 
722 		/* Calculate length of packet, then send that */
723 
724 		count += 14;		/* Ethernet header len */
725 
726 		mm = m;
727 		for (mm = m; mm; mm = mm->m_next) {
728 			count += mm->m_len;
729 		}
730 		if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
731 			goto nend;
732 		if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
733 			goto nend;
734 
735 		/* Send dummy ethernet header */
736 		for (i = 0; i < 12; i++) {
737 			if (clpoutbyte(i, LPMAXSPIN1, ppbus))
738 				goto nend;
739 			chksum += i;
740 		}
741 
742 		if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
743 			goto nend;
744 		if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
745 			goto nend;
746 		chksum += 0x08 + 0x00;		/* Add into checksum */
747 
748 		mm = m;
749 		do {
750 			cp = mtod(mm, u_char *);
751 			len = mm->m_len;
752 			while (len--) {
753 				chksum += *cp;
754 				if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
755 					goto nend;
756 			}
757 		} while ((mm = mm->m_next));
758 
759 		/* Send checksum */
760 		if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
761 			goto nend;
762 
763 		/* Go quiescent */
764 		ppb_wdtr(ppbus, 0);
765 
766 		err = 0;			/* No errors */
767 
768 	nend:
769 		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
770 		if (err)  {			/* if we didn't timeout... */
771 			ifp->if_oerrors++;
772 			lprintf("X");
773 		} else {
774 			ifp->if_opackets++;
775 			ifp->if_obytes += m->m_pkthdr.len;
776 			if (bpf_peers_present(ifp->if_bpf))
777 				lptap(ifp, m);
778 		}
779 
780 		m_freem(m);
781 
782 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
783 			lprintf("^");
784 			lp_intr(sc);
785 		}
786 		ppb_unlock(ppbus);
787 		return (0);
788 	}
789 
790 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
791 		lprintf("&");
792 		lp_intr(sc);
793 	}
794 
795 	if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
796 		goto end;
797 	if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
798 		goto end;
799 
800 	mm = m;
801 	do {
802 		cp = mtod(mm, u_char *);
803 		len = mm->m_len;
804 		while (len--)
805 			if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
806 				goto end;
807 	} while ((mm = mm->m_next));
808 
809 	err = 0;			/* no errors were encountered */
810 
811 end:
812 	--cp;
813 	ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
814 
815 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
816 	if (err)  {			/* if we didn't timeout... */
817 		ifp->if_oerrors++;
818 		lprintf("X");
819 	} else {
820 		ifp->if_opackets++;
821 		ifp->if_obytes += m->m_pkthdr.len;
822 		if (bpf_peers_present(ifp->if_bpf))
823 			lptap(ifp, m);
824 	}
825 
826 	m_freem(m);
827 
828 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
829 		lprintf("^");
830 		lp_intr(sc);
831 	}
832 
833 	ppb_unlock(ppbus);
834 	return (0);
835 }
836 
837 static device_method_t lp_methods[] = {
838   	/* device interface */
839 	DEVMETHOD(device_identify,	lp_identify),
840 	DEVMETHOD(device_probe,		lp_probe),
841 	DEVMETHOD(device_attach,	lp_attach),
842 	DEVMETHOD(device_detach,	lp_detach),
843 
844 	{ 0, 0 }
845 };
846 
847 static driver_t lp_driver = {
848 	"plip",
849 	lp_methods,
850 	sizeof(struct lp_data),
851 };
852 
853 DRIVER_MODULE(plip, ppbus, lp_driver, lp_devclass, lp_module_handler, 0);
854 MODULE_DEPEND(plip, ppbus, 1, 1, 1);
855