xref: /freebsd/sys/dev/ppbus/if_plip.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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_types.h>
101 #include <net/netisr.h>
102 #include <net/route.h>
103 
104 #include <netinet/in.h>
105 #include <netinet/in_var.h>
106 
107 #include <net/bpf.h>
108 
109 #include <dev/ppbus/ppbconf.h>
110 #include "ppbus_if.h"
111 #include <dev/ppbus/ppbio.h>
112 
113 #ifndef LPMTU			/* MTU for the lp# interfaces */
114 #define	LPMTU		1500
115 #endif
116 
117 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
118 #define	LPMAXSPIN1	8000   /* Spinning for remote intr to happen */
119 #endif
120 
121 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
122 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
123 #endif
124 
125 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
126 #define	LPMAXERRS	100
127 #endif
128 
129 #define	CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
130 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
131 #define	MLPIPHDRLEN	CLPIPHDRLEN
132 
133 #define	LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
134 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
135 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
136 #define	MLPIPHDRLEN	LPIPHDRLEN
137 #endif
138 
139 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
140 
141 #define	lprintf		if (lptflag) printf
142 
143 #ifdef PLIP_DEBUG
144 static int volatile lptflag = 1;
145 #else
146 static int volatile lptflag = 0;
147 #endif
148 
149 struct lp_data {
150 	struct  ifnet	*sc_ifp;
151 	device_t	sc_dev;
152 	u_char		*sc_ifbuf;
153 	int		sc_iferrs;
154 
155 	struct resource *res_irq;
156 	void		*sc_intr_cookie;
157 };
158 
159 static struct mtx lp_tables_lock;
160 MTX_SYSINIT(lp_tables, &lp_tables_lock, "plip tables", MTX_DEF);
161 
162 /* Tables for the lp# interface */
163 static u_char *txmith;
164 #define	txmitl (txmith + (1 * LPIPTBLSIZE))
165 #define	trecvh (txmith + (2 * LPIPTBLSIZE))
166 #define	trecvl (txmith + (3 * LPIPTBLSIZE))
167 
168 static u_char *ctxmith;
169 #define	ctxmitl (ctxmith + (1 * LPIPTBLSIZE))
170 #define	ctrecvh (ctxmith + (2 * LPIPTBLSIZE))
171 #define	ctrecvl (ctxmith + (3 * LPIPTBLSIZE))
172 
173 /* Functions for the lp# interface */
174 static int lpinittables(void);
175 static int lpioctl(struct ifnet *, u_long, caddr_t);
176 static int lpoutput(struct ifnet *, struct mbuf *, struct sockaddr *,
177        struct route *);
178 static void lpstop(struct lp_data *);
179 static void lp_intr(void *);
180 static int lp_module_handler(module_t, int, void *);
181 
182 #define	DEVTOSOFTC(dev) \
183 	((struct lp_data *)device_get_softc(dev))
184 
185 static devclass_t lp_devclass;
186 
187 static int
188 lp_module_handler(module_t mod, int what, void *arg)
189 {
190 
191 	switch (what) {
192 	case MOD_UNLOAD:
193 		mtx_lock(&lp_tables_lock);
194 		if (txmith != NULL) {
195 			free(txmith, M_DEVBUF);
196 			txmith = NULL;
197 		}
198 		if (ctxmith != NULL) {
199 			free(ctxmith, M_DEVBUF);
200 			ctxmith = NULL;
201 		}
202 		mtx_unlock(&lp_tables_lock);
203 		break;
204 	case MOD_LOAD:
205 	case MOD_QUIESCE:
206 		break;
207 	default:
208 		return (EOPNOTSUPP);
209 	}
210 	return (0);
211 }
212 
213 static void
214 lp_identify(driver_t *driver, device_t parent)
215 {
216 	device_t dev;
217 
218 	dev = device_find_child(parent, "plip", -1);
219 	if (!dev)
220 		BUS_ADD_CHILD(parent, 0, "plip", -1);
221 }
222 
223 static int
224 lp_probe(device_t dev)
225 {
226 
227 	device_set_desc(dev, "PLIP network interface");
228 
229 	return (0);
230 }
231 
232 static int
233 lp_attach(device_t dev)
234 {
235 	struct lp_data *lp = DEVTOSOFTC(dev);
236 	struct ifnet *ifp;
237 	int error, rid = 0;
238 
239 	lp->sc_dev = dev;
240 
241 	/*
242 	 * Reserve the interrupt resource.  If we don't have one, the
243 	 * attach fails.
244 	 */
245 	lp->res_irq = bus_alloc_resource_any(dev, SYS_RES_IRQ, &rid,
246 	    RF_SHAREABLE);
247 	if (lp->res_irq == 0) {
248 		device_printf(dev, "cannot reserve interrupt, failed.\n");
249 		return (ENXIO);
250 	}
251 
252 	ifp = lp->sc_ifp = if_alloc(IFT_PARA);
253 	if (ifp == NULL) {
254 		return (ENOSPC);
255 	}
256 
257 	ifp->if_softc = lp;
258 	if_initname(ifp, device_get_name(dev), device_get_unit(dev));
259 	ifp->if_mtu = LPMTU;
260 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
261 	ifp->if_ioctl = lpioctl;
262 	ifp->if_output = lpoutput;
263 	ifp->if_hdrlen = 0;
264 	ifp->if_addrlen = 0;
265 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
266 	if_attach(ifp);
267 
268 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
269 
270 	/*
271 	 * Attach our interrupt handler.  It is only called while we
272 	 * own the ppbus.
273 	 */
274 	error = bus_setup_intr(dev, lp->res_irq, INTR_TYPE_NET | INTR_MPSAFE,
275 	    NULL, lp_intr, lp, &lp->sc_intr_cookie);
276 	if (error) {
277 		bpfdetach(ifp);
278 		if_detach(ifp);
279 		bus_release_resource(dev, SYS_RES_IRQ, 0, lp->res_irq);
280 		device_printf(dev, "Unable to register interrupt handler\n");
281 		return (error);
282 	}
283 
284 	return (0);
285 }
286 
287 static int
288 lp_detach(device_t dev)
289 {
290 	struct lp_data *sc = device_get_softc(dev);
291 	device_t ppbus = device_get_parent(dev);
292 
293 	ppb_lock(ppbus);
294 	lpstop(sc);
295 	ppb_unlock(ppbus);
296 	bpfdetach(sc->sc_ifp);
297 	if_detach(sc->sc_ifp);
298 	bus_teardown_intr(dev, sc->res_irq, sc->sc_intr_cookie);
299 	bus_release_resource(dev, SYS_RES_IRQ, 0, sc->res_irq);
300 	return (0);
301 }
302 
303 /*
304  * Build the translation tables for the LPIP (BSD unix) protocol.
305  * We don't want to calculate these nasties in our tight loop, so we
306  * precalculate them when we initialize.
307  */
308 static int
309 lpinittables(void)
310 {
311 	int i;
312 
313 	mtx_lock(&lp_tables_lock);
314 	if (txmith == NULL)
315 		txmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
316 
317 	if (txmith == NULL) {
318 		mtx_unlock(&lp_tables_lock);
319 		return (1);
320 	}
321 
322 	if (ctxmith == NULL)
323 		ctxmith = malloc(4 * LPIPTBLSIZE, M_DEVBUF, M_NOWAIT);
324 
325 	if (ctxmith == NULL) {
326 		mtx_unlock(&lp_tables_lock);
327 		return (1);
328 	}
329 
330 	for (i = 0; i < LPIPTBLSIZE; i++) {
331 		ctxmith[i] = (i & 0xF0) >> 4;
332 		ctxmitl[i] = 0x10 | (i & 0x0F);
333 		ctrecvh[i] = (i & 0x78) << 1;
334 		ctrecvl[i] = (i & 0x78) >> 3;
335 	}
336 
337 	for (i = 0; i < LPIPTBLSIZE; i++) {
338 		txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
339 		txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
340 		trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
341 		trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
342 	}
343 	mtx_unlock(&lp_tables_lock);
344 
345 	return (0);
346 }
347 
348 static void
349 lpstop(struct lp_data *sc)
350 {
351 	device_t ppbus = device_get_parent(sc->sc_dev);
352 
353 	ppb_assert_locked(ppbus);
354 	ppb_wctr(ppbus, 0x00);
355 	sc->sc_ifp->if_drv_flags &= ~(IFF_DRV_RUNNING | IFF_DRV_OACTIVE);
356 	free(sc->sc_ifbuf, M_DEVBUF);
357 	sc->sc_ifbuf = NULL;
358 
359 	/* IFF_UP is not set, try to release the bus anyway */
360 	ppb_release_bus(ppbus, sc->sc_dev);
361 }
362 
363 static int
364 lpinit_locked(struct ifnet *ifp)
365 {
366 	struct lp_data *sc = ifp->if_softc;
367 	device_t dev = sc->sc_dev;
368 	device_t ppbus = device_get_parent(dev);
369 	int error;
370 
371 	ppb_assert_locked(ppbus);
372 	error = ppb_request_bus(ppbus, dev, PPB_DONTWAIT);
373 	if (error)
374 		return (error);
375 
376 	/* Now IFF_UP means that we own the bus */
377 	ppb_set_mode(ppbus, PPB_COMPATIBLE);
378 
379 	if (lpinittables()) {
380 		ppb_release_bus(ppbus, dev);
381 		return (ENOBUFS);
382 	}
383 
384 	sc->sc_ifbuf = malloc(sc->sc_ifp->if_mtu + MLPIPHDRLEN,
385 	    M_DEVBUF, M_NOWAIT);
386 	if (sc->sc_ifbuf == NULL) {
387 		ppb_release_bus(ppbus, dev);
388 		return (ENOBUFS);
389 	}
390 
391 	ppb_wctr(ppbus, IRQENABLE);
392 
393 	ifp->if_drv_flags |= IFF_DRV_RUNNING;
394 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
395 	return (0);
396 }
397 
398 /*
399  * Process an ioctl request.
400  */
401 static int
402 lpioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
403 {
404 	struct lp_data *sc = ifp->if_softc;
405 	device_t dev = sc->sc_dev;
406 	device_t ppbus = device_get_parent(dev);
407 	struct ifaddr *ifa = (struct ifaddr *)data;
408 	struct ifreq *ifr = (struct ifreq *)data;
409 	u_char *ptr;
410 	int error;
411 
412 	switch (cmd) {
413 	case SIOCSIFDSTADDR:
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 			/* mbuf is free'd on failure. */
589 			netisr_queue(NETISR_IP, top);
590 			ppb_lock(ppbus);
591 		}
592 		return;
593 	}
594 	while ((ppb_rstr(ppbus) & LPIP_SHAKE)) {
595 		len = sc->sc_ifp->if_mtu + LPIPHDRLEN;
596 		bp  = sc->sc_ifbuf;
597 		while (len--) {
598 
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 		sc->sc_ifp->if_ipackets++;
632 		sc->sc_ifp->if_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 			/* mbuf is free'd on failure. */
641 			netisr_queue(NETISR_IP, top);
642 			ppb_lock(ppbus);
643 		}
644 	}
645 	return;
646 
647 err:
648 	ppb_wdtr(ppbus, 0);
649 	lprintf("R");
650 	sc->sc_ifp->if_ierrors++;
651 	sc->sc_iferrs++;
652 
653 	/*
654 	 * We are not able to send receive anything for now,
655 	 * so stop wasting our time
656 	 */
657 	if (sc->sc_iferrs > LPMAXERRS) {
658 		if_printf(sc->sc_ifp, "Too many errors, Going off-line.\n");
659 		ppb_wctr(ppbus, 0x00);
660 		sc->sc_ifp->if_drv_flags &= ~IFF_DRV_RUNNING;
661 		sc->sc_iferrs = 0;
662 	}
663 }
664 
665 static __inline int
666 lpoutbyte(u_char byte, int spin, device_t ppbus)
667 {
668 
669 	ppb_wdtr(ppbus, txmith[byte]);
670 	while (!(ppb_rstr(ppbus) & LPIP_SHAKE))
671 		if (--spin == 0)
672 			return (1);
673 	ppb_wdtr(ppbus, txmitl[byte]);
674 	while (ppb_rstr(ppbus) & LPIP_SHAKE)
675 		if (--spin == 0)
676 			return (1);
677 	return (0);
678 }
679 
680 static int
681 lpoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
682     struct route *ro)
683 {
684 	struct lp_data *sc = ifp->if_softc;
685 	device_t dev = sc->sc_dev;
686 	device_t ppbus = device_get_parent(dev);
687 	int err;
688 	struct mbuf *mm;
689 	u_char *cp = "\0\0";
690 	u_char chksum = 0;
691 	int count = 0;
692 	int i, len, spin;
693 
694 	/* We need a sensible value if we abort */
695 	cp++;
696 	ppb_lock(ppbus);
697 	ifp->if_drv_flags |= IFF_DRV_OACTIVE;
698 
699 	err = 1;		/* assume we're aborting because of an error */
700 
701 	/* Suspend (on laptops) or receive-errors might have taken us offline */
702 	ppb_wctr(ppbus, IRQENABLE);
703 
704 	if (ifp->if_flags & IFF_LINK0) {
705 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
706 			lprintf("&");
707 			lp_intr(sc);
708 		}
709 
710 		/* Alert other end to pending packet */
711 		spin = LPMAXSPIN1;
712 		ppb_wdtr(ppbus, 0x08);
713 		while ((ppb_rstr(ppbus) & 0x08) == 0)
714 			if (--spin == 0) {
715 				goto nend;
716 			}
717 
718 		/* Calculate length of packet, then send that */
719 
720 		count += 14;		/* Ethernet header len */
721 
722 		mm = m;
723 		for (mm = m; mm; mm = mm->m_next) {
724 			count += mm->m_len;
725 		}
726 		if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
727 			goto nend;
728 		if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
729 			goto nend;
730 
731 		/* Send dummy ethernet header */
732 		for (i = 0; i < 12; i++) {
733 			if (clpoutbyte(i, LPMAXSPIN1, ppbus))
734 				goto nend;
735 			chksum += i;
736 		}
737 
738 		if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
739 			goto nend;
740 		if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
741 			goto nend;
742 		chksum += 0x08 + 0x00;		/* Add into checksum */
743 
744 		mm = m;
745 		do {
746 			cp = mtod(mm, u_char *);
747 			len = mm->m_len;
748 			while (len--) {
749 				chksum += *cp;
750 				if (clpoutbyte(*cp++, LPMAXSPIN2, ppbus))
751 					goto nend;
752 			}
753 		} while ((mm = mm->m_next));
754 
755 		/* Send checksum */
756 		if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
757 			goto nend;
758 
759 		/* Go quiescent */
760 		ppb_wdtr(ppbus, 0);
761 
762 		err = 0;			/* No errors */
763 
764 	nend:
765 		ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
766 		if (err)  {			/* if we didn't timeout... */
767 			ifp->if_oerrors++;
768 			lprintf("X");
769 		} else {
770 			ifp->if_opackets++;
771 			ifp->if_obytes += m->m_pkthdr.len;
772 			if (bpf_peers_present(ifp->if_bpf))
773 				lptap(ifp, m);
774 		}
775 
776 		m_freem(m);
777 
778 		if (!(ppb_rstr(ppbus) & CLPIP_SHAKE)) {
779 			lprintf("^");
780 			lp_intr(sc);
781 		}
782 		ppb_unlock(ppbus);
783 		return (0);
784 	}
785 
786 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
787 		lprintf("&");
788 		lp_intr(sc);
789 	}
790 
791 	if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
792 		goto end;
793 	if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
794 		goto end;
795 
796 	mm = m;
797 	do {
798 		cp = mtod(mm, u_char *);
799 		len = mm->m_len;
800 		while (len--)
801 			if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
802 				goto end;
803 	} while ((mm = mm->m_next));
804 
805 	err = 0;			/* no errors were encountered */
806 
807 end:
808 	--cp;
809 	ppb_wdtr(ppbus, txmitl[*cp] ^ 0x17);
810 
811 	ifp->if_drv_flags &= ~IFF_DRV_OACTIVE;
812 	if (err)  {			/* if we didn't timeout... */
813 		ifp->if_oerrors++;
814 		lprintf("X");
815 	} else {
816 		ifp->if_opackets++;
817 		ifp->if_obytes += m->m_pkthdr.len;
818 		if (bpf_peers_present(ifp->if_bpf))
819 			lptap(ifp, m);
820 	}
821 
822 	m_freem(m);
823 
824 	if (ppb_rstr(ppbus) & LPIP_SHAKE) {
825 		lprintf("^");
826 		lp_intr(sc);
827 	}
828 
829 	ppb_unlock(ppbus);
830 	return (0);
831 }
832 
833 static device_method_t lp_methods[] = {
834   	/* device interface */
835 	DEVMETHOD(device_identify,	lp_identify),
836 	DEVMETHOD(device_probe,		lp_probe),
837 	DEVMETHOD(device_attach,	lp_attach),
838 	DEVMETHOD(device_detach,	lp_detach),
839 
840 	{ 0, 0 }
841 };
842 
843 static driver_t lp_driver = {
844 	"plip",
845 	lp_methods,
846 	sizeof(struct lp_data),
847 };
848 
849 DRIVER_MODULE(plip, ppbus, lp_driver, lp_devclass, lp_module_handler, 0);
850 MODULE_DEPEND(plip, ppbus, 1, 1, 1);
851