xref: /freebsd/sys/dev/ppbus/if_plip.c (revision 8eb2bee6c0f4957c6c1cea826e59cda4d18a2a64)
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 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 == NULL) {
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 == NULL) {
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 		/* Ack. the request */
541 		ppb_wdtr(ppbus, 0x01);
542 
543 		/* Get the packet length */
544 		j = clpinbyte(LPMAXSPIN2, ppbus);
545 		if (j == -1)
546 			goto err;
547 		len = j;
548 		j = clpinbyte(LPMAXSPIN2, ppbus);
549 		if (j == -1)
550 			goto err;
551 		len = len + (j << 8);
552 		if (len > sc->sc_ifp->if_mtu + MLPIPHDRLEN)
553 			goto err;
554 
555 		bp = sc->sc_ifbuf;
556 
557 		while (len--) {
558 			j = clpinbyte(LPMAXSPIN2, ppbus);
559 			if (j == -1) {
560 				goto err;
561 			}
562 			*bp++ = j;
563 		}
564 
565 		/* Get and ignore checksum */
566 		j = clpinbyte(LPMAXSPIN2, ppbus);
567 		if (j == -1) {
568 			goto err;
569 		}
570 
571 		len = bp - sc->sc_ifbuf;
572 		if (len <= CLPIPHDRLEN)
573 			goto err;
574 
575 		sc->sc_iferrs = 0;
576 
577 		len -= CLPIPHDRLEN;
578 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
579 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
580 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, sc->sc_ifp,
581 		    0);
582 		if (top) {
583 			ppb_unlock(ppbus);
584 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
585 				lptap(sc->sc_ifp, top);
586 
587 			M_SETFIB(top, sc->sc_ifp->if_fib);
588 
589 			/* mbuf is free'd on failure. */
590 			netisr_queue(NETISR_IP, top);
591 			ppb_lock(ppbus);
592 		}
593 		return;
594 	}
595 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
596 		len = sc->sc_ifp->if_mtu + LPIPHDRLEN;
597 		bp  = sc->sc_ifbuf;
598 		while (len--) {
599 			cl = ppb_rstr(ppbus);
600 			ppb_wdtr(ppbus, 8);
601 
602 			j = LPMAXSPIN2;
603 			while ((ppb_rstr(ppbus) & LPIP_SHAKE))
604 				if (!--j)
605 					goto err;
606 
607 			c = ppb_rstr(ppbus);
608 			ppb_wdtr(ppbus, 0);
609 
610 			*bp++= trecvh[cl] | trecvl[c];
611 
612 			j = LPMAXSPIN2;
613 			while (!((cl = ppb_rstr(ppbus)) & LPIP_SHAKE)) {
614 				if (cl != c &&
615 				    (((cl = ppb_rstr(ppbus)) ^ 0xb8) & 0xf8) ==
616 				    (c & 0xf8))
617 					goto end;
618 				if (!--j)
619 					goto err;
620 			}
621 		}
622 
623 	end:
624 		len = bp - sc->sc_ifbuf;
625 		if (len <= LPIPHDRLEN)
626 			goto err;
627 
628 		sc->sc_iferrs = 0;
629 
630 		len -= LPIPHDRLEN;
631 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IPACKETS, 1);
632 		if_inc_counter(sc->sc_ifp, IFCOUNTER_IBYTES, len);
633 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, sc->sc_ifp,
634 		    0);
635 		if (top) {
636 			ppb_unlock(ppbus);
637 			if (bpf_peers_present(sc->sc_ifp->if_bpf))
638 				lptap(sc->sc_ifp, top);
639 
640 			M_SETFIB(top, sc->sc_ifp->if_fib);
641 
642 			/* mbuf is free'd on failure. */
643 			netisr_queue(NETISR_IP, top);
644 			ppb_lock(ppbus);
645 		}
646 	}
647 	return;
648 
649 err:
650 	ppb_wdtr(ppbus, 0);
651 	lprintf("R");
652 	if_inc_counter(sc->sc_ifp, IFCOUNTER_IERRORS, 1);
653 	sc->sc_iferrs++;
654 
655 	/*
656 	 * We are not able to send receive anything for now,
657 	 * so stop wasting our time
658 	 */
659 	if (sc->sc_iferrs > LPMAXERRS) {
660 		if_printf(sc->sc_ifp, "Too many errors, Going off-line.\n");
661 		ppb_wctr(ppbus, 0x00);
662 		sc->sc_ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
663 		sc->sc_iferrs = 0;
664 	}
665 }
666 
667 static __inline int
668 lpoutbyte(u_char byte, int spin, device_t ppbus)
669 {
670 
671 	ppb_wdtr(ppbus, txmith[byte]);
672 	while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
673 		if (--spin == 0)
674 			return (1);
675 	ppb_wdtr(ppbus, txmitl[byte]);
676 	while (ppb_rstr(ppbus) & LPIP_SHAKE)
677 		if (--spin == 0)
678 			return (1);
679 	return (0);
680 }
681 
682 static int
683 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
684     struct route *ro)
685 {
686 	struct lp_data *sc = ifp->if_softc;
687 	device_t dev = sc->sc_dev;
688 	device_t ppbus = device_get_parent(dev);
689 	int err;
690 	struct mbuf *mm;
691 	u_char *cp = "\0\0";
692 	u_char chksum = 0;
693 	int count = 0;
694 	int i, len, spin;
695 
696 	/* We need a sensible value if we abort */
697 	cp++;
698 	ppb_lock(ppbus);
699 	ifp->if_drv_flags |= IFF_DRV_OACTIVE;
700 
701 	err = 1;		/* assume we're aborting because of an error */
702 
703 	/* Suspend (on laptops) or receive-errors might have taken us offline */
704 	ppb_wctr(ppbus, IRQENABLE);
705 
706 	if (ifp->if_flags & IFF_LINK0) {
707 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
708 			lprintf("&");
709 			lp_intr(sc);
710 		}
711 
712 		/* Alert other end to pending packet */
713 		spin = LPMAXSPIN1;
714 		ppb_wdtr(ppbus, 0x08);
715 		while ((ppb_rstr(ppbus) & 0x08) == 0)
716 			if (--spin == 0) {
717 				goto nend;
718 			}
719 
720 		/* Calculate length of packet, then send that */
721 
722 		count += 14;		/* Ethernet header len */
723 
724 		mm = m;
725 		for (mm = m; mm; mm = mm->m_next) {
726 			count += mm->m_len;
727 		}
728 		if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
729 			goto nend;
730 		if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
731 			goto nend;
732 
733 		/* Send dummy ethernet header */
734 		for (i = 0; i < 12; i++) {
735 			if (clpoutbyte(i, LPMAXSPIN1, ppbus))
736 				goto nend;
737 			chksum += i;
738 		}
739 
740 		if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
741 			goto nend;
742 		if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
743 			goto nend;
744 		chksum += 0x08 + 0x00;		/* Add into checksum */
745 
746 		mm = m;
747 		do {
748 			cp = mtod(mm, u_char *);
749 			len = mm->m_len;
750 			while (len--) {
751 				chksum += *cp;
752 				if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
753 					goto nend;
754 			}
755 		} while ((mm = mm->m_next));
756 
757 		/* Send checksum */
758 		if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
759 			goto nend;
760 
761 		/* Go quiescent */
762 		ppb_wdtr(ppbus, 0);
763 
764 		err = 0;			/* No errors */
765 
766 	nend:
767 		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
768 		if (err)  {			/* if we didn't timeout... */
769 			if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
770 			lprintf("X");
771 		} else {
772 			if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
773 			if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
774 			if (bpf_peers_present(ifp->if_bpf))
775 				lptap(ifp, m);
776 		}
777 
778 		m_freem(m);
779 
780 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
781 			lprintf("^");
782 			lp_intr(sc);
783 		}
784 		ppb_unlock(ppbus);
785 		return (0);
786 	}
787 
788 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
789 		lprintf("&");
790 		lp_intr(sc);
791 	}
792 
793 	if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
794 		goto end;
795 	if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
796 		goto end;
797 
798 	mm = m;
799 	do {
800 		cp = mtod(mm, u_char *);
801 		len = mm->m_len;
802 		while (len--)
803 			if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
804 				goto end;
805 	} while ((mm = mm->m_next));
806 
807 	err = 0;			/* no errors were encountered */
808 
809 end:
810 	--cp;
811 	ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
812 
813 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
814 	if (err)  {			/* if we didn't timeout... */
815 		if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
816 		lprintf("X");
817 	} else {
818 		if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
819 		if_inc_counter(ifp, IFCOUNTER_OBYTES, m->m_pkthdr.len);
820 		if (bpf_peers_present(ifp->if_bpf))
821 			lptap(ifp, m);
822 	}
823 
824 	m_freem(m);
825 
826 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
827 		lprintf("^");
828 		lp_intr(sc);
829 	}
830 
831 	ppb_unlock(ppbus);
832 	return (0);
833 }
834 
835 static device_method_t lp_methods[] = {
836   	/* device interface */
837 	DEVMETHOD(device_identify,	lp_identify),
838 	DEVMETHOD(device_probe,		lp_probe),
839 	DEVMETHOD(device_attach,	lp_attach),
840 	DEVMETHOD(device_detach,	lp_detach),
841 	{ 0, 0 }
842 };
843 
844 static driver_t lp_driver = {
845 	"plip",
846 	lp_methods,
847 	sizeof(struct lp_data),
848 };
849 
850 DRIVER_MODULE(plip, ppbus, lp_driver, lp_module_handler, NULL);
851 MODULE_DEPEND(plip, ppbus, 1, 1, 1);
852