xref: /freebsd/sys/dev/ppbus/if_plip.c (revision d37eb51047221dc3322b34db1038ff3aa533883f)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 /*
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(if_t, u_long, caddr_t);
177 static int lpoutput(if_t, 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 int
187 lp_module_handler(module_t mod, int what, void *arg)
188 {
189 
190 	switch (what) {
191 	case MOD_UNLOAD:
192 		mtx_lock(&lp_tables_lock);
193 		if (txmith != NULL) {
194 			free(txmith, M_DEVBUF);
195 			txmith = NULL;
196 		}
197 		if (ctxmith != NULL) {
198 			free(ctxmith, M_DEVBUF);
199 			ctxmith = NULL;
200 		}
201 		mtx_unlock(&lp_tables_lock);
202 		break;
203 	case MOD_LOAD:
204 	case MOD_QUIESCE:
205 		break;
206 	default:
207 		return (EOPNOTSUPP);
208 	}
209 	return (0);
210 }
211 
212 static void
213 lp_identify(driver_t *driver, device_t parent)
214 {
215 	device_t dev;
216 
217 	dev = device_find_child(parent, "plip", -1);
218 	if (!dev)
219 		BUS_ADD_CHILD(parent, 0, "plip", -1);
220 }
221 
222 static int
223 lp_probe(device_t dev)
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 	if_t ifp;
236 	int error, rid = 0;
237 
238 	lp->sc_dev = dev;
239 
240 	/*
241 	 * Reserve the interrupt resource.  If we don't have one, the
242 	 * attach fails.
243 	 */
244 	lp->res_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
245 	    RF_SHAREABLE);
246 	if (lp->res_irq == NULL) {
247 		device_printf(dev, "cannot reserve interrupt, failed.\n");
248 		return (ENXIO);
249 	}
250 
251 	ifp = lp->sc_ifp = if_alloc(IFT_PARA);
252 	if (ifp == NULL) {
253 		return (ENOSPC);
254 	}
255 
256 	if_setsoftc(ifp, lp);
257 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
258 	if_setmtu(ifp, LPMTU);
259 	if_setflags(ifp, IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST);
260 	if_setioctlfn(ifp, lpioctl);
261 	if_setoutputfn(ifp, lpoutput);
262 	if_setsendqlen(ifp, ifqmaxlen);
263 	if_attach(ifp);
264 
265 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
266 
267 	/*
268 	 * Attach our interrupt handler.  It is only called while we
269 	 * own the ppbus.
270 	 */
271 	error = bus_setup_intr(dev, lp->res_irq, INTR_TYPE_NET | INTR_MPSAFE,
272 	    NULL, lp_intr, lp, &lp->sc_intr_cookie);
273 	if (error) {
274 		bpfdetach(ifp);
275 		if_detach(ifp);
276 		bus_release_resource(dev, SYS_RES_IRQ, 0, lp->res_irq);
277 		device_printf(dev, "Unable to register interrupt handler\n");
278 		return (error);
279 	}
280 
281 	return (0);
282 }
283 
284 static int
285 lp_detach(device_t dev)
286 {
287 	struct lp_data *sc = device_get_softc(dev);
288 	device_t ppbus = device_get_parent(dev);
289 
290 	ppb_lock(ppbus);
291 	lpstop(sc);
292 	ppb_unlock(ppbus);
293 	bpfdetach(sc->sc_ifp);
294 	if_detach(sc->sc_ifp);
295 	bus_teardown_intr(dev, sc->res_irq, sc->sc_intr_cookie);
296 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->res_irq);
297 	return (0);
298 }
299 
300 /*
301  * Build the translation tables for the LPIP (BSD unix) protocol.
302  * We don't want to calculate these nasties in our tight loop, so we
303  * precalculate them when we initialize.
304  */
305 static int
306 lpinittables(void)
307 {
308 	int i;
309 
310 	mtx_lock(&lp_tables_lock);
311 	if (txmith == NULL)
312 		txmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
313 
314 	if (txmith == NULL) {
315 		mtx_unlock(&lp_tables_lock);
316 		return (1);
317 	}
318 
319 	if (ctxmith == NULL)
320 		ctxmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
321 
322 	if (ctxmith == NULL) {
323 		mtx_unlock(&lp_tables_lock);
324 		return (1);
325 	}
326 
327 	for (i = 0; i < LPIPTBLSIZE; i++) {
328 		ctxmith[i] = (i & 0xF0) >> 4;
329 		ctxmitl[i] = 0x10 | (i & 0x0F);
330 		ctrecvh[i] = (i & 0x78) << 1;
331 		ctrecvl[i] = (i & 0x78) >> 3;
332 	}
333 
334 	for (i = 0; i < LPIPTBLSIZE; i++) {
335 		txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
336 		txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
337 		trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
338 		trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
339 	}
340 	mtx_unlock(&lp_tables_lock);
341 
342 	return (0);
343 }
344 
345 static void
346 lpstop(struct lp_data *sc)
347 {
348 	device_t ppbus = device_get_parent(sc->sc_dev);
349 
350 	ppb_assert_locked(ppbus);
351 	ppb_wctr(ppbus, 0x00);
352 	if_setdrvflagbits(sc->sc_ifp, 0, (IFF_DRV_RUNNING | IFF_DRV_OACTIVE));
353 	free(sc->sc_ifbuf, M_DEVBUF);
354 	sc->sc_ifbuf = NULL;
355 
356 	/* IFF_UP is not set, try to release the bus anyway */
357 	ppb_release_bus(ppbus, sc->sc_dev);
358 }
359 
360 static int
361 lpinit_locked(if_t ifp)
362 {
363 	struct lp_data *sc = if_getsoftc(ifp);
364 	device_t dev = sc->sc_dev;
365 	device_t ppbus = device_get_parent(dev);
366 	int error;
367 
368 	ppb_assert_locked(ppbus);
369 	error = ppb_request_bus(ppbus, dev, PPB_DONTWAIT);
370 	if (error)
371 		return (error);
372 
373 	/* Now IFF_UP means that we own the bus */
374 	ppb_set_mode(ppbus, PPB_COMPATIBLE);
375 
376 	if (lpinittables()) {
377 		ppb_release_bus(ppbus, dev);
378 		return (ENOBUFS);
379 	}
380 
381 	sc->sc_ifbuf = malloc(if_getmtu(sc->sc_ifp) + MLPIPHDRLEN,
382 	    M_DEVBUF, M_NOWAIT);
383 	if (sc->sc_ifbuf == NULL) {
384 		ppb_release_bus(ppbus, dev);
385 		return (ENOBUFS);
386 	}
387 
388 	ppb_wctr(ppbus, IRQENABLE);
389 
390 	if_setdrvflagbits(ifp, IFF_DRV_RUNNING, 0);
391 	if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
392 	return (0);
393 }
394 
395 /*
396  * Process an ioctl request.
397  */
398 static int
399 lpioctl(if_t ifp, u_long cmd, caddr_t data)
400 {
401 	struct lp_data *sc = if_getsoftc(ifp);
402 	device_t dev = sc->sc_dev;
403 	device_t ppbus = device_get_parent(dev);
404 	struct ifaddr *ifa = (struct ifaddr *)data;
405 	struct ifreq *ifr = (struct ifreq *)data;
406 	u_char *ptr;
407 	int error;
408 
409 	switch (cmd) {
410 	case SIOCAIFADDR:
411 	case SIOCSIFADDR:
412 		if (ifa->ifa_addr->sa_family != AF_INET)
413 			return (EAFNOSUPPORT);
414 
415 		if_setflagbits(ifp, IFF_UP, 0);
416 		/* FALLTHROUGH */
417 	case SIOCSIFFLAGS:
418 		error = 0;
419 		ppb_lock(ppbus);
420 		if ((!(if_getflags(ifp) & IFF_UP)) &&
421 		    (if_getdrvflags(ifp) & IFF_DRV_RUNNING))
422 			lpstop(sc);
423 		else if (((if_getflags(ifp) & IFF_UP)) &&
424 		    (!(if_getdrvflags(ifp) & IFF_DRV_RUNNING)))
425 			error = lpinit_locked(ifp);
426 		ppb_unlock(ppbus);
427 		return (error);
428 
429 	case SIOCSIFMTU:
430 		ppb_lock(ppbus);
431 		if (if_getdrvflags(ifp) & IFF_DRV_RUNNING) {
432 			ptr = malloc(ifr->ifr_mtu + MLPIPHDRLEN, M_DEVBUF,
433 			    M_NOWAIT);
434 			if (ptr == NULL) {
435 				ppb_unlock(ppbus);
436 				return (ENOBUFS);
437 			}
438 			if (sc->sc_ifbuf)
439 				free(sc->sc_ifbuf, M_DEVBUF);
440 			sc->sc_ifbuf = ptr;
441 		}
442 		if_setmtu(ifp, ifr->ifr_mtu);
443 		ppb_unlock(ppbus);
444 		break;
445 
446 	case SIOCGIFMTU:
447 		ifr->ifr_mtu = if_getmtu(sc->sc_ifp);
448 		break;
449 
450 	case SIOCADDMULTI:
451 	case SIOCDELMULTI:
452 		if (ifr == NULL) {
453 			return (EAFNOSUPPORT);		/* XXX */
454 		}
455 		switch (ifr->ifr_addr.sa_family) {
456 		case AF_INET:
457 			break;
458 		default:
459 			return (EAFNOSUPPORT);
460 		}
461 		break;
462 
463 	case SIOCGIFMEDIA:
464 		/*
465 		 * No ifmedia support at this stage; maybe use it
466 		 * in future for eg. protocol selection.
467 		 */
468 		return (EINVAL);
469 
470 	default:
471 		lprintf("LP:ioctl(0x%lx)\n", cmd);
472 		return (EINVAL);
473 	}
474 	return (0);
475 }
476 
477 static __inline int
478 clpoutbyte(u_char byte, int spin, device_t ppbus)
479 {
480 
481 	ppb_wdtr(ppbus, ctxmitl[byte]);
482 	while (ppb_rstr(ppbus) & CLPIP_SHAKE)
483 		if (--spin == 0) {
484 			return (1);
485 		}
486 	ppb_wdtr(ppbus, ctxmith[byte]);
487 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
488 		if (--spin == 0) {
489 			return (1);
490 		}
491 	return (0);
492 }
493 
494 static __inline int
495 clpinbyte(int spin, device_t ppbus)
496 {
497 	u_char c, cl;
498 
499 	while ((ppb_rstr(ppbus) & CLPIP_SHAKE))
500 		if (!--spin) {
501 			return (-1);
502 		}
503 	cl = ppb_rstr(ppbus);
504 	ppb_wdtr(ppbus, 0x10);
505 
506 	while (!(ppb_rstr(ppbus) & CLPIP_SHAKE))
507 		if (!--spin) {
508 			return (-1);
509 		}
510 	c = ppb_rstr(ppbus);
511 	ppb_wdtr(ppbus, 0x00);
512 
513 	return (ctrecvl[cl] | ctrecvh[c]);
514 }
515 
516 static void
517 lptap(if_t ifp, struct mbuf *m)
518 {
519 	u_int32_t af = AF_INET;
520 
521 	bpf_mtap2_if(ifp, &af, sizeof(af), m);
522 }
523 
524 static void
525 lp_intr(void *arg)
526 {
527 	struct lp_data *sc = arg;
528 	device_t ppbus = device_get_parent(sc->sc_dev);
529 	int len, j;
530 	u_char *bp;
531 	u_char c, cl;
532 	struct mbuf *top;
533 
534 	ppb_assert_locked(ppbus);
535 	if (if_getflags(sc->sc_ifp) & IFF_LINK0) {
536 		/* Ack. the request */
537 		ppb_wdtr(ppbus, 0x01);
538 
539 		/* Get the packet length */
540 		j = clpinbyte(LPMAXSPIN2, ppbus);
541 		if (j == -1)
542 			goto err;
543 		len = j;
544 		j = clpinbyte(LPMAXSPIN2, ppbus);
545 		if (j == -1)
546 			goto err;
547 		len = len + (j << 8);
548 		if (len > if_getmtu(sc->sc_ifp) + MLPIPHDRLEN)
549 			goto err;
550 
551 		bp = sc->sc_ifbuf;
552 
553 		while (len--) {
554 			j = clpinbyte(LPMAXSPIN2, ppbus);
555 			if (j == -1) {
556 				goto err;
557 			}
558 			*bp++ = j;
559 		}
560 
561 		/* Get and ignore checksum */
562 		j = clpinbyte(LPMAXSPIN2, ppbus);
563 		if (j == -1) {
564 			goto err;
565 		}
566 
567 		len = bp - sc->sc_ifbuf;
568 		if (len <= CLPIPHDRLEN)
569 			goto err;
570 
571 		sc->sc_iferrs = 0;
572 
573 		len -= CLPIPHDRLEN;
574 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
575 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
576 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, sc->sc_ifp,
577 		    0);
578 		if (top) {
579 			ppb_unlock(ppbus);
580 			lptap(sc->sc_ifp, top);
581 
582 			M_SETFIB(top, if_getfib(sc->sc_ifp));
583 
584 			/* mbuf is free'd on failure. */
585 			netisr_queue(NETISR_IP, top);
586 			ppb_lock(ppbus);
587 		}
588 		return;
589 	}
590 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
591 		len = if_getmtu(sc->sc_ifp) + LPIPHDRLEN;
592 		bp  = sc->sc_ifbuf;
593 		while (len--) {
594 			cl = ppb_rstr(ppbus);
595 			ppb_wdtr(ppbus, 8);
596 
597 			j = LPMAXSPIN2;
598 			while ((ppb_rstr(ppbus) & LPIP_SHAKE))
599 				if (!--j)
600 					goto err;
601 
602 			c = ppb_rstr(ppbus);
603 			ppb_wdtr(ppbus, 0);
604 
605 			*bp++= trecvh[cl] | trecvl[c];
606 
607 			j = LPMAXSPIN2;
608 			while (!((cl = ppb_rstr(ppbus)) & LPIP_SHAKE)) {
609 				if (cl != c &&
610 				    (((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
611 				    (c & 0xf8))
612 					goto end;
613 				if (!--j)
614 					goto err;
615 			}
616 		}
617 
618 	end:
619 		len = bp - sc->sc_ifbuf;
620 		if (len <= LPIPHDRLEN)
621 			goto err;
622 
623 		sc->sc_iferrs = 0;
624 
625 		len -= LPIPHDRLEN;
626 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
627 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
628 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, sc->sc_ifp,
629 		    0);
630 		if (top) {
631 			ppb_unlock(ppbus);
632 			lptap(sc->sc_ifp, top);
633 
634 			M_SETFIB(top, if_getfib(sc->sc_ifp));
635 
636 			/* mbuf is free'd on failure. */
637 			netisr_queue(NETISR_IP, top);
638 			ppb_lock(ppbus);
639 		}
640 	}
641 	return;
642 
643 err:
644 	ppb_wdtr(ppbus, 0);
645 	lprintf("R");
646 	if_inc_counter(sc->sc_ifp, IFCOUNTER_IERRORS, 1);
647 	sc->sc_iferrs++;
648 
649 	/*
650 	 * We are not able to send receive anything for now,
651 	 * so stop wasting our time
652 	 */
653 	if (sc->sc_iferrs > LPMAXERRS) {
654 		if_printf(sc->sc_ifp, "Too many errors, Going off-line.\n");
655 		ppb_wctr(ppbus, 0x00);
656 		if_setdrvflagbits(sc->sc_ifp, 0, IFF_DRV_RUNNING);
657 		sc->sc_iferrs = 0;
658 	}
659 }
660 
661 static __inline int
662 lpoutbyte(u_char byte, int spin, device_t ppbus)
663 {
664 
665 	ppb_wdtr(ppbus, txmith[byte]);
666 	while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
667 		if (--spin == 0)
668 			return (1);
669 	ppb_wdtr(ppbus, txmitl[byte]);
670 	while (ppb_rstr(ppbus) & LPIP_SHAKE)
671 		if (--spin == 0)
672 			return (1);
673 	return (0);
674 }
675 
676 static int
677 lpoutput(if_t ifp, struct mbuf *m, const struct sockaddr *dst,
678     struct route *ro)
679 {
680 	struct lp_data *sc = if_getsoftc(ifp);
681 	device_t dev = sc->sc_dev;
682 	device_t ppbus = device_get_parent(dev);
683 	int err;
684 	struct mbuf *mm;
685 	u_char *cp = "\0\0";
686 	u_char chksum = 0;
687 	int count = 0;
688 	int i, len, spin;
689 
690 	/* We need a sensible value if we abort */
691 	cp++;
692 	ppb_lock(ppbus);
693 	if_setdrvflagbits(ifp, IFF_DRV_OACTIVE, 0);
694 
695 	err = 1;		/* assume we're aborting because of an error */
696 
697 	/* Suspend (on laptops) or receive-errors might have taken us offline */
698 	ppb_wctr(ppbus, IRQENABLE);
699 
700 	if (if_getflags(ifp) & IFF_LINK0) {
701 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
702 			lprintf("&");
703 			lp_intr(sc);
704 		}
705 
706 		/* Alert other end to pending packet */
707 		spin = LPMAXSPIN1;
708 		ppb_wdtr(ppbus, 0x08);
709 		while ((ppb_rstr(ppbus) & 0x08) == 0)
710 			if (--spin == 0) {
711 				goto nend;
712 			}
713 
714 		/* Calculate length of packet, then send that */
715 
716 		count += 14;		/* Ethernet header len */
717 
718 		mm = m;
719 		for (mm = m; mm; mm = mm->m_next) {
720 			count += mm->m_len;
721 		}
722 		if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
723 			goto nend;
724 		if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
725 			goto nend;
726 
727 		/* Send dummy ethernet header */
728 		for (i = 0; i < 12; i++) {
729 			if (clpoutbyte(i, LPMAXSPIN1, ppbus))
730 				goto nend;
731 			chksum += i;
732 		}
733 
734 		if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
735 			goto nend;
736 		if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
737 			goto nend;
738 		chksum += 0x08 + 0x00;		/* Add into checksum */
739 
740 		mm = m;
741 		do {
742 			cp = mtod(mm, u_char *);
743 			len = mm->m_len;
744 			while (len--) {
745 				chksum += *cp;
746 				if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
747 					goto nend;
748 			}
749 		} while ((mm = mm->m_next));
750 
751 		/* Send checksum */
752 		if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
753 			goto nend;
754 
755 		/* Go quiescent */
756 		ppb_wdtr(ppbus, 0);
757 
758 		err = 0;			/* No errors */
759 
760 	nend:
761 		if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
762 		if (err)  {			/* if we didn't timeout... */
763 			if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
764 			lprintf("X");
765 		} else {
766 			if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
767 			if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
768 			lptap(ifp, m);
769 		}
770 
771 		m_freem(m);
772 
773 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
774 			lprintf("^");
775 			lp_intr(sc);
776 		}
777 		ppb_unlock(ppbus);
778 		return (0);
779 	}
780 
781 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
782 		lprintf("&");
783 		lp_intr(sc);
784 	}
785 
786 	if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
787 		goto end;
788 	if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
789 		goto end;
790 
791 	mm = m;
792 	do {
793 		cp = mtod(mm, u_char *);
794 		len = mm->m_len;
795 		while (len--)
796 			if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
797 				goto end;
798 	} while ((mm = mm->m_next));
799 
800 	err = 0;			/* no errors were encountered */
801 
802 end:
803 	--cp;
804 	ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
805 
806 	if_setdrvflagbits(ifp, 0, IFF_DRV_OACTIVE);
807 	if (err)  {			/* if we didn't timeout... */
808 		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
809 		lprintf("X");
810 	} else {
811 		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
812 		if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
813 		lptap(ifp, m);
814 	}
815 
816 	m_freem(m);
817 
818 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
819 		lprintf("^");
820 		lp_intr(sc);
821 	}
822 
823 	ppb_unlock(ppbus);
824 	return (0);
825 }
826 
827 static device_method_t lp_methods[] = {
828   	/* device interface */
829 	DEVMETHOD(device_identify,	lp_identify),
830 	DEVMETHOD(device_probe,		lp_probe),
831 	DEVMETHOD(device_attach,	lp_attach),
832 	DEVMETHOD(device_detach,	lp_detach),
833 	{ 0, 0 }
834 };
835 
836 static driver_t lp_driver = {
837 	"plip",
838 	lp_methods,
839 	sizeof(struct lp_data),
840 };
841 
842 DRIVER_MODULE(plip, ppbus, lp_driver, lp_module_handler, NULL);
843 MODULE_DEPEND(plip, ppbus, 1, 1, 1);
844