xref: /freebsd/sys/dev/ppbus/if_plip.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1997 Poul-Henning Kamp
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  *	From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 /*
35  * Parallel port TCP/IP interfaces added.  I looked at the driver from
36  * MACH but this is a complete rewrite, and btw. incompatible, and it
37  * should perform better too.  I have never run the MACH driver though.
38  *
39  * This driver sends two bytes (0x08, 0x00) in front of each packet,
40  * to allow us to distinguish another format later.
41  *
42  * Now added a Linux/Crynwr compatibility mode which is enabled using
43  * IF_LINK0 - Tim Wilkinson.
44  *
45  * TODO:
46  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
47  *
48  * Connect the two computers using a Laplink parallel cable to use this
49  * feature:
50  *
51  *      +----------------------------------------+
52  * 	|A-name	A-End	B-End	Descr.	Port/Bit |
53  *      +----------------------------------------+
54  *	|DATA0	2	15	Data	0/0x01   |
55  *	|-ERROR	15	2	   	1/0x08   |
56  *      +----------------------------------------+
57  *	|DATA1	3	13	Data	0/0x02	 |
58  *	|+SLCT	13	3	   	1/0x10   |
59  *      +----------------------------------------+
60  *	|DATA2	4	12	Data	0/0x04   |
61  *	|+PE	12	4	   	1/0x20   |
62  *      +----------------------------------------+
63  *	|DATA3	5	10	Strobe	0/0x08   |
64  *	|-ACK	10	5	   	1/0x40   |
65  *      +----------------------------------------+
66  *	|DATA4	6	11	Data	0/0x10   |
67  *	|BUSY	11	6	   	1/~0x80  |
68  *      +----------------------------------------+
69  *	|GND	18-25	18-25	GND	-        |
70  *      +----------------------------------------+
71  *
72  * Expect transfer-rates up to 75 kbyte/sec.
73  *
74  * If GCC could correctly grok
75  *	register int port asm("edx")
76  * the code would be cleaner
77  *
78  * Poul-Henning Kamp <phk@freebsd.org>
79  */
80 
81 /*
82  * Update for ppbus, PLIP support only - Nicolas Souchu
83  */
84 
85 #include "opt_plip.h"
86 
87 #include <sys/param.h>
88 #include <sys/systm.h>
89 #include <sys/module.h>
90 #include <sys/bus.h>
91 #include <sys/mbuf.h>
92 #include <sys/socket.h>
93 #include <sys/sockio.h>
94 #include <sys/kernel.h>
95 #include <sys/malloc.h>
96 
97 #include <machine/bus.h>
98 #include <machine/resource.h>
99 #include <sys/rman.h>
100 
101 #include <net/if.h>
102 #include <net/if_var.h>
103 #include <net/if_types.h>
104 #include <net/netisr.h>
105 #include <net/route.h>
106 
107 #include <netinet/in.h>
108 #include <netinet/in_var.h>
109 
110 #include <net/bpf.h>
111 
112 #include <dev/ppbus/ppbconf.h>
113 #include "ppbus_if.h"
114 #include <dev/ppbus/ppbio.h>
115 
116 #ifndef LPMTU			/* MTU for the lp# interfaces */
117 #define	LPMTU		1500
118 #endif
119 
120 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
121 #define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
122 #endif
123 
124 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
125 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
126 #endif
127 
128 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
129 #define	LPMAXERRS	100
130 #endif
131 
132 #define	CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
133 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
134 #define	MLPIPHDRLEN	CLPIPHDRLEN
135 
136 #define	LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
137 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
138 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
139 #define	MLPIPHDRLEN	LPIPHDRLEN
140 #endif
141 
142 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
143 
144 #define	lprintf		if (lptflag) printf
145 
146 #ifdef PLIP_DEBUG
147 static int volatile lptflag = 1;
148 #else
149 static int volatile lptflag = 0;
150 #endif
151 
152 struct lp_data {
153 	struct  ifnet	*sc_ifp;
154 	device_t	sc_dev;
155 	u_char		*sc_ifbuf;
156 	int		sc_iferrs;
157 
158 	struct resource *res_irq;
159 	void		*sc_intr_cookie;
160 };
161 
162 static struct mtx lp_tables_lock;
163 MTX_SYSINIT(lp_tables, &lp_tables_lock, "plip tables", MTX_DEF);
164 
165 /* Tables for the lp# interface */
166 static u_char *txmith;
167 #define	txmitl (txmith + (1 * LPIPTBLSIZE))
168 #define	trecvh (txmith + (2 * LPIPTBLSIZE))
169 #define	trecvl (txmith + (3 * LPIPTBLSIZE))
170 
171 static u_char *ctxmith;
172 #define	ctxmitl (ctxmith + (1 * LPIPTBLSIZE))
173 #define	ctrecvh (ctxmith + (2 * LPIPTBLSIZE))
174 #define	ctrecvl (ctxmith + (3 * LPIPTBLSIZE))
175 
176 /* Functions for the lp# interface */
177 static int lpinittables(void);
178 static int lpioctl(struct ifnet *, u_long, caddr_t);
179 static int lpoutput(struct ifnet *, struct mbuf *, const struct sockaddr *,
180        struct route *);
181 static void lpstop(struct lp_data *);
182 static void lp_intr(void *);
183 static int lp_module_handler(module_t, int, void *);
184 
185 #define	DEVTOSOFTC(dev) \
186 	((struct lp_data *)device_get_softc(dev))
187 
188 static devclass_t lp_devclass;
189 
190 static int
191 lp_module_handler(module_t mod, int what, void *arg)
192 {
193 
194 	switch (what) {
195 	case MOD_UNLOAD:
196 		mtx_lock(&lp_tables_lock);
197 		if (txmith != NULL) {
198 			free(txmith, M_DEVBUF);
199 			txmith = NULL;
200 		}
201 		if (ctxmith != NULL) {
202 			free(ctxmith, M_DEVBUF);
203 			ctxmith = NULL;
204 		}
205 		mtx_unlock(&lp_tables_lock);
206 		break;
207 	case MOD_LOAD:
208 	case MOD_QUIESCE:
209 		break;
210 	default:
211 		return (EOPNOTSUPP);
212 	}
213 	return (0);
214 }
215 
216 static void
217 lp_identify(driver_t *driver, device_t parent)
218 {
219 	device_t dev;
220 
221 	dev = device_find_child(parent, "plip", -1);
222 	if (!dev)
223 		BUS_ADD_CHILD(parent, 0, "plip", -1);
224 }
225 
226 static int
227 lp_probe(device_t dev)
228 {
229 
230 	device_set_desc(dev, "PLIP network interface");
231 
232 	return (0);
233 }
234 
235 static int
236 lp_attach(device_t dev)
237 {
238 	struct lp_data *lp = DEVTOSOFTC(dev);
239 	struct ifnet *ifp;
240 	int error, rid = 0;
241 
242 	lp->sc_dev = dev;
243 
244 	/*
245 	 * Reserve the interrupt resource.  If we don't have one, the
246 	 * attach fails.
247 	 */
248 	lp->res_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
249 	    RF_SHAREABLE);
250 	if (lp->res_irq == NULL) {
251 		device_printf(dev, "cannot reserve interrupt, failed.\n");
252 		return (ENXIO);
253 	}
254 
255 	ifp = lp->sc_ifp = if_alloc(IFT_PARA);
256 	if (ifp == NULL) {
257 		return (ENOSPC);
258 	}
259 
260 	ifp->if_softc = lp;
261 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
262 	ifp->if_mtu = LPMTU;
263 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
264 	ifp->if_ioctl = lpioctl;
265 	ifp->if_output = lpoutput;
266 	ifp->if_hdrlen = 0;
267 	ifp->if_addrlen = 0;
268 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
269 	if_attach(ifp);
270 
271 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
272 
273 	/*
274 	 * Attach our interrupt handler.  It is only called while we
275 	 * own the ppbus.
276 	 */
277 	error = bus_setup_intr(dev, lp->res_irq, INTR_TYPE_NET | INTR_MPSAFE,
278 	    NULL, lp_intr, lp, &lp->sc_intr_cookie);
279 	if (error) {
280 		bpfdetach(ifp);
281 		if_detach(ifp);
282 		bus_release_resource(dev, SYS_RES_IRQ, 0, lp->res_irq);
283 		device_printf(dev, "Unable to register interrupt handler\n");
284 		return (error);
285 	}
286 
287 	return (0);
288 }
289 
290 static int
291 lp_detach(device_t dev)
292 {
293 	struct lp_data *sc = device_get_softc(dev);
294 	device_t ppbus = device_get_parent(dev);
295 
296 	ppb_lock(ppbus);
297 	lpstop(sc);
298 	ppb_unlock(ppbus);
299 	bpfdetach(sc->sc_ifp);
300 	if_detach(sc->sc_ifp);
301 	bus_teardown_intr(dev, sc->res_irq, sc->sc_intr_cookie);
302 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->res_irq);
303 	return (0);
304 }
305 
306 /*
307  * Build the translation tables for the LPIP (BSD unix) protocol.
308  * We don't want to calculate these nasties in our tight loop, so we
309  * precalculate them when we initialize.
310  */
311 static int
312 lpinittables(void)
313 {
314 	int i;
315 
316 	mtx_lock(&lp_tables_lock);
317 	if (txmith == NULL)
318 		txmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
319 
320 	if (txmith == NULL) {
321 		mtx_unlock(&lp_tables_lock);
322 		return (1);
323 	}
324 
325 	if (ctxmith == NULL)
326 		ctxmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
327 
328 	if (ctxmith == NULL) {
329 		mtx_unlock(&lp_tables_lock);
330 		return (1);
331 	}
332 
333 	for (i = 0; i < LPIPTBLSIZE; i++) {
334 		ctxmith[i] = (i & 0xF0) >> 4;
335 		ctxmitl[i] = 0x10 | (i & 0x0F);
336 		ctrecvh[i] = (i & 0x78) << 1;
337 		ctrecvl[i] = (i & 0x78) >> 3;
338 	}
339 
340 	for (i = 0; i < LPIPTBLSIZE; i++) {
341 		txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
342 		txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
343 		trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
344 		trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
345 	}
346 	mtx_unlock(&lp_tables_lock);
347 
348 	return (0);
349 }
350 
351 static void
352 lpstop(struct lp_data *sc)
353 {
354 	device_t ppbus = device_get_parent(sc->sc_dev);
355 
356 	ppb_assert_locked(ppbus);
357 	ppb_wctr(ppbus, 0x00);
358 	sc->sc_ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
359 	free(sc->sc_ifbuf, M_DEVBUF);
360 	sc->sc_ifbuf = NULL;
361 
362 	/* IFF_UP is not set, try to release the bus anyway */
363 	ppb_release_bus(ppbus, sc->sc_dev);
364 }
365 
366 static int
367 lpinit_locked(struct ifnet *ifp)
368 {
369 	struct lp_data *sc = ifp->if_softc;
370 	device_t dev = sc->sc_dev;
371 	device_t ppbus = device_get_parent(dev);
372 	int error;
373 
374 	ppb_assert_locked(ppbus);
375 	error = ppb_request_bus(ppbus, dev, PPB_DONTWAIT);
376 	if (error)
377 		return (error);
378 
379 	/* Now IFF_UP means that we own the bus */
380 	ppb_set_mode(ppbus, PPB_COMPATIBLE);
381 
382 	if (lpinittables()) {
383 		ppb_release_bus(ppbus, dev);
384 		return (ENOBUFS);
385 	}
386 
387 	sc->sc_ifbuf = malloc(sc->sc_ifp->if_mtu + MLPIPHDRLEN,
388 	    M_DEVBUF, M_NOWAIT);
389 	if (sc->sc_ifbuf == NULL) {
390 		ppb_release_bus(ppbus, dev);
391 		return (ENOBUFS);
392 	}
393 
394 	ppb_wctr(ppbus, IRQENABLE);
395 
396 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
397 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
398 	return (0);
399 }
400 
401 /*
402  * Process an ioctl request.
403  */
404 static int
405 lpioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
406 {
407 	struct lp_data *sc = ifp->if_softc;
408 	device_t dev = sc->sc_dev;
409 	device_t ppbus = device_get_parent(dev);
410 	struct ifaddr *ifa = (struct ifaddr *)data;
411 	struct ifreq *ifr = (struct ifreq *)data;
412 	u_char *ptr;
413 	int error;
414 
415 	switch (cmd) {
416 	case SIOCAIFADDR:
417 	case SIOCSIFADDR:
418 		if (ifa->ifa_addr->sa_family != AF_INET)
419 			return (EAFNOSUPPORT);
420 
421 		ifp->if_flags |= IFF_UP;
422 		/* FALLTHROUGH */
423 	case SIOCSIFFLAGS:
424 		error = 0;
425 		ppb_lock(ppbus);
426 		if ((!(ifp->if_flags & IFF_UP)) &&
427 		    (ifp->if_drv_flags & IFF_DRV_RUNNING))
428 			lpstop(sc);
429 		else if (((ifp->if_flags & IFF_UP)) &&
430 		    (!(ifp->if_drv_flags & IFF_DRV_RUNNING)))
431 			error = lpinit_locked(ifp);
432 		ppb_unlock(ppbus);
433 		return (error);
434 
435 	case SIOCSIFMTU:
436 		ppb_lock(ppbus);
437 		if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
438 			ptr = malloc(ifr->ifr_mtu + MLPIPHDRLEN, M_DEVBUF,
439 			    M_NOWAIT);
440 			if (ptr == NULL) {
441 				ppb_unlock(ppbus);
442 				return (ENOBUFS);
443 			}
444 			if (sc->sc_ifbuf)
445 				free(sc->sc_ifbuf, M_DEVBUF);
446 			sc->sc_ifbuf = ptr;
447 		}
448 		sc->sc_ifp->if_mtu = ifr->ifr_mtu;
449 		ppb_unlock(ppbus);
450 		break;
451 
452 	case SIOCGIFMTU:
453 		ifr->ifr_mtu = sc->sc_ifp->if_mtu;
454 		break;
455 
456 	case SIOCADDMULTI:
457 	case SIOCDELMULTI:
458 		if (ifr == NULL) {
459 			return (EAFNOSUPPORT);		/* XXX */
460 		}
461 		switch (ifr->ifr_addr.sa_family) {
462 		case AF_INET:
463 			break;
464 		default:
465 			return (EAFNOSUPPORT);
466 		}
467 		break;
468 
469 	case SIOCGIFMEDIA:
470 		/*
471 		 * No ifmedia support at this stage; maybe use it
472 		 * in future for eg. protocol selection.
473 		 */
474 		return (EINVAL);
475 
476 	default:
477 		lprintf("LP:ioctl(0x%lx)\n", cmd);
478 		return (EINVAL);
479 	}
480 	return (0);
481 }
482 
483 static __inline int
484 clpoutbyte(u_char byte, int spin, device_t ppbus)
485 {
486 
487 	ppb_wdtr(ppbus, ctxmitl[byte]);
488 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
489 		if (--spin == 0) {
490 			return (1);
491 		}
492 	ppb_wdtr(ppbus, ctxmith[byte]);
493 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
494 		if (--spin == 0) {
495 			return (1);
496 		}
497 	return (0);
498 }
499 
500 static __inline int
501 clpinbyte(int spin, device_t ppbus)
502 {
503 	u_char c, cl;
504 
505 	while ((ppb_rstr(ppbus) & CLPIP_SHAKE))
506 		if (!--spin) {
507 			return (-1);
508 		}
509 	cl = ppb_rstr(ppbus);
510 	ppb_wdtr(ppbus, 0x10);
511 
512 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
513 		if (!--spin) {
514 			return (-1);
515 		}
516 	c = ppb_rstr(ppbus);
517 	ppb_wdtr(ppbus, 0x00);
518 
519 	return (ctrecvl[cl] | ctrecvh[c]);
520 }
521 
522 static void
523 lptap(struct ifnet *ifp, struct mbuf *m)
524 {
525 	u_int32_t af = AF_INET;
526 
527 	bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
528 }
529 
530 static void
531 lp_intr(void *arg)
532 {
533 	struct lp_data *sc = arg;
534 	device_t ppbus = device_get_parent(sc->sc_dev);
535 	int len, j;
536 	u_char *bp;
537 	u_char c, cl;
538 	struct mbuf *top;
539 
540 	ppb_assert_locked(ppbus);
541 	if (sc->sc_ifp->if_flags & IFF_LINK0) {
542 
543 		/* Ack. the request */
544 		ppb_wdtr(ppbus, 0x01);
545 
546 		/* Get the packet length */
547 		j = clpinbyte(LPMAXSPIN2, ppbus);
548 		if (j == -1)
549 			goto err;
550 		len = j;
551 		j = clpinbyte(LPMAXSPIN2, ppbus);
552 		if (j == -1)
553 			goto err;
554 		len = len + (j << 8);
555 		if (len > sc->sc_ifp->if_mtu + MLPIPHDRLEN)
556 			goto err;
557 
558 		bp = sc->sc_ifbuf;
559 
560 		while (len--) {
561 			j = clpinbyte(LPMAXSPIN2, ppbus);
562 			if (j == -1) {
563 				goto err;
564 			}
565 			*bp++ = j;
566 		}
567 
568 		/* Get and ignore checksum */
569 		j = clpinbyte(LPMAXSPIN2, ppbus);
570 		if (j == -1) {
571 			goto err;
572 		}
573 
574 		len = bp - sc->sc_ifbuf;
575 		if (len <= CLPIPHDRLEN)
576 			goto err;
577 
578 		sc->sc_iferrs = 0;
579 
580 		len -= CLPIPHDRLEN;
581 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
582 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
583 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, sc->sc_ifp,
584 		    0);
585 		if (top) {
586 			ppb_unlock(ppbus);
587 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
588 				lptap(sc->sc_ifp, top);
589 
590 			M_SETFIB(top, sc->sc_ifp->if_fib);
591 
592 			/* mbuf is free'd on failure. */
593 			netisr_queue(NETISR_IP, top);
594 			ppb_lock(ppbus);
595 		}
596 		return;
597 	}
598 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
599 		len = sc->sc_ifp->if_mtu + LPIPHDRLEN;
600 		bp  = sc->sc_ifbuf;
601 		while (len--) {
602 
603 			cl = ppb_rstr(ppbus);
604 			ppb_wdtr(ppbus, 8);
605 
606 			j = LPMAXSPIN2;
607 			while ((ppb_rstr(ppbus) & LPIP_SHAKE))
608 				if (!--j)
609 					goto err;
610 
611 			c = ppb_rstr(ppbus);
612 			ppb_wdtr(ppbus, 0);
613 
614 			*bp++= trecvh[cl] | trecvl[c];
615 
616 			j = LPMAXSPIN2;
617 			while (!((cl = ppb_rstr(ppbus)) & LPIP_SHAKE)) {
618 				if (cl != c &&
619 				    (((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
620 				    (c & 0xf8))
621 					goto end;
622 				if (!--j)
623 					goto err;
624 			}
625 		}
626 
627 	end:
628 		len = bp - sc->sc_ifbuf;
629 		if (len <= LPIPHDRLEN)
630 			goto err;
631 
632 		sc->sc_iferrs = 0;
633 
634 		len -= LPIPHDRLEN;
635 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
636 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
637 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, sc->sc_ifp,
638 		    0);
639 		if (top) {
640 			ppb_unlock(ppbus);
641 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
642 				lptap(sc->sc_ifp, top);
643 
644 			M_SETFIB(top, sc->sc_ifp->if_fib);
645 
646 			/* mbuf is free'd on failure. */
647 			netisr_queue(NETISR_IP, top);
648 			ppb_lock(ppbus);
649 		}
650 	}
651 	return;
652 
653 err:
654 	ppb_wdtr(ppbus, 0);
655 	lprintf("R");
656 	if_inc_counter(sc->sc_ifp, IFCOUNTER_IERRORS, 1);
657 	sc->sc_iferrs++;
658 
659 	/*
660 	 * We are not able to send receive anything for now,
661 	 * so stop wasting our time
662 	 */
663 	if (sc->sc_iferrs > LPMAXERRS) {
664 		if_printf(sc->sc_ifp, "Too many errors, Going off-line.\n");
665 		ppb_wctr(ppbus, 0x00);
666 		sc->sc_ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
667 		sc->sc_iferrs = 0;
668 	}
669 }
670 
671 static __inline int
672 lpoutbyte(u_char byte, int spin, device_t ppbus)
673 {
674 
675 	ppb_wdtr(ppbus, txmith[byte]);
676 	while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
677 		if (--spin == 0)
678 			return (1);
679 	ppb_wdtr(ppbus, txmitl[byte]);
680 	while (ppb_rstr(ppbus) & LPIP_SHAKE)
681 		if (--spin == 0)
682 			return (1);
683 	return (0);
684 }
685 
686 static int
687 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
688     struct route *ro)
689 {
690 	struct lp_data *sc = ifp->if_softc;
691 	device_t dev = sc->sc_dev;
692 	device_t ppbus = device_get_parent(dev);
693 	int err;
694 	struct mbuf *mm;
695 	u_char *cp = "\0\0";
696 	u_char chksum = 0;
697 	int count = 0;
698 	int i, len, spin;
699 
700 	/* We need a sensible value if we abort */
701 	cp++;
702 	ppb_lock(ppbus);
703 	ifp->if_drv_flags |= IFF_DRV_OACTIVE;
704 
705 	err = 1;		/* assume we're aborting because of an error */
706 
707 	/* Suspend (on laptops) or receive-errors might have taken us offline */
708 	ppb_wctr(ppbus, IRQENABLE);
709 
710 	if (ifp->if_flags & IFF_LINK0) {
711 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
712 			lprintf("&");
713 			lp_intr(sc);
714 		}
715 
716 		/* Alert other end to pending packet */
717 		spin = LPMAXSPIN1;
718 		ppb_wdtr(ppbus, 0x08);
719 		while ((ppb_rstr(ppbus) & 0x08) == 0)
720 			if (--spin == 0) {
721 				goto nend;
722 			}
723 
724 		/* Calculate length of packet, then send that */
725 
726 		count += 14;		/* Ethernet header len */
727 
728 		mm = m;
729 		for (mm = m; mm; mm = mm->m_next) {
730 			count += mm->m_len;
731 		}
732 		if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
733 			goto nend;
734 		if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
735 			goto nend;
736 
737 		/* Send dummy ethernet header */
738 		for (i = 0; i < 12; i++) {
739 			if (clpoutbyte(i, LPMAXSPIN1, ppbus))
740 				goto nend;
741 			chksum += i;
742 		}
743 
744 		if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
745 			goto nend;
746 		if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
747 			goto nend;
748 		chksum += 0x08 + 0x00;		/* Add into checksum */
749 
750 		mm = m;
751 		do {
752 			cp = mtod(mm, u_char *);
753 			len = mm->m_len;
754 			while (len--) {
755 				chksum += *cp;
756 				if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
757 					goto nend;
758 			}
759 		} while ((mm = mm->m_next));
760 
761 		/* Send checksum */
762 		if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
763 			goto nend;
764 
765 		/* Go quiescent */
766 		ppb_wdtr(ppbus, 0);
767 
768 		err = 0;			/* No errors */
769 
770 	nend:
771 		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
772 		if (err)  {			/* if we didn't timeout... */
773 			if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
774 			lprintf("X");
775 		} else {
776 			if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
777 			if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
778 			if (bpf_peers_present(ifp->if_bpf))
779 				lptap(ifp, m);
780 		}
781 
782 		m_freem(m);
783 
784 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
785 			lprintf("^");
786 			lp_intr(sc);
787 		}
788 		ppb_unlock(ppbus);
789 		return (0);
790 	}
791 
792 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
793 		lprintf("&");
794 		lp_intr(sc);
795 	}
796 
797 	if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
798 		goto end;
799 	if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
800 		goto end;
801 
802 	mm = m;
803 	do {
804 		cp = mtod(mm, u_char *);
805 		len = mm->m_len;
806 		while (len--)
807 			if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
808 				goto end;
809 	} while ((mm = mm->m_next));
810 
811 	err = 0;			/* no errors were encountered */
812 
813 end:
814 	--cp;
815 	ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
816 
817 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
818 	if (err)  {			/* if we didn't timeout... */
819 		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
820 		lprintf("X");
821 	} else {
822 		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
823 		if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
824 		if (bpf_peers_present(ifp->if_bpf))
825 			lptap(ifp, m);
826 	}
827 
828 	m_freem(m);
829 
830 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
831 		lprintf("^");
832 		lp_intr(sc);
833 	}
834 
835 	ppb_unlock(ppbus);
836 	return (0);
837 }
838 
839 static device_method_t lp_methods[] = {
840   	/* device interface */
841 	DEVMETHOD(device_identify,	lp_identify),
842 	DEVMETHOD(device_probe,		lp_probe),
843 	DEVMETHOD(device_attach,	lp_attach),
844 	DEVMETHOD(device_detach,	lp_detach),
845 
846 	{ 0, 0 }
847 };
848 
849 static driver_t lp_driver = {
850 	"plip",
851 	lp_methods,
852 	sizeof(struct lp_data),
853 };
854 
855 DRIVER_MODULE(plip, ppbus, lp_driver, lp_devclass, lp_module_handler, 0);
856 MODULE_DEPEND(plip, ppbus, 1, 1, 1);
857