xref: /netbsd-src/sys/dev/ppbus/if_plip.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /* $NetBSD: if_plip.c,v 1.36 2020/02/04 20:46:51 jdolecek Exp $ */
2 
3 /*-
4  * Copyright (c) 1997 Poul-Henning Kamp
5  * Copyright (c) 2003, 2004 Gary Thorpe <gathorpe@users.sourceforge.net>
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	From Id: lpt.c,v 1.55.2.1 1996/11/12 09:08:38 phk Exp
30  * FreeBSD: src/sys/dev/ppbus/if_plip.c,v 1.19.2.1 2000/05/24 00:20:57 n_hibma Exp
31  */
32 
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: if_plip.c,v 1.36 2020/02/04 20:46:51 jdolecek Exp $");
35 
36 /*
37  * Parallel port TCP/IP interfaces added.  I looked at the driver from
38  * MACH but this is a complete rewrite, and btw. incompatible, and it
39  * should perform better too.  I have never run the MACH driver though.
40  *
41  * This driver sends two bytes (0x08, 0x00) in front of each packet,
42  * to allow us to distinguish another format later.
43  *
44  * Now added a Linux/Crynwr compatibility mode which is enabled using
45  * IF_LINK0 - Tim Wilkinson.
46  *
47  * TODO:
48  *    Make HDLC/PPP mode, use IF_LLC1 to enable.
49  *
50  * Connect the two computers using a Laplink parallel cable to use this
51  * feature:
52  *
53  *      +----------------------------------------+
54  * 	|A-name	A-End	B-End	Descr.	Port/Bit |
55  *      +----------------------------------------+
56  *	|DATA0	2	15	Data	0/0x01   |
57  *	|-ERROR	15	2	   	1/0x08   |
58  *      +----------------------------------------+
59  *	|DATA1	3	13	Data	0/0x02	 |
60  *	|+SLCT	13	3	   	1/0x10   |
61  *      +----------------------------------------+
62  *	|DATA2	4	12	Data	0/0x04   |
63  *	|+PE	12	4	   	1/0x20   |
64  *      +----------------------------------------+
65  *	|DATA3	5	10	Strobe	0/0x08   |
66  *	|-ACK	10	5	   	1/0x40   |
67  *      +----------------------------------------+
68  *	|DATA4	6	11	Data	0/0x10   |
69  *	|BUSY	11	6	   	1/~0x80  |
70  *      +----------------------------------------+
71  *	|GND	18-25	18-25	GND	-        |
72  *      +----------------------------------------+
73  *
74  * Expect transfer-rates up to 75 kbyte/sec.
75  *
76  * If GCC could correctly grok
77  *	register int port __asm("edx")
78  * the code would be cleaner
79  *
80  * Poul-Henning Kamp <phk@freebsd.org>
81  */
82 
83 /*
84  * Update for ppbus, PLIP support only - Nicolas Souchu
85  */
86 
87 #include "opt_inet.h"
88 #include "opt_plip.h"
89 
90 #include <sys/systm.h>
91 #include <sys/param.h>
92 #include <sys/proc.h>
93 #include <sys/types.h>
94 #include <sys/device.h>
95 #include <sys/ioctl.h>
96 #include <sys/malloc.h>
97 #include <sys/mbuf.h>
98 
99 #include <net/if.h>
100 #include <net/if_types.h>
101 #include <net/netisr.h>
102 
103 #include <sys/time.h>
104 #include <net/bpf.h>
105 
106 #ifdef INET
107 #include <netinet/in_var.h>
108 /* #include <netinet/in.h> */
109 #else
110 #error Cannot config lp/plip without inet
111 #endif
112 
113 #include <dev/ppbus/ppbus_base.h>
114 #include <dev/ppbus/ppbus_device.h>
115 #include <dev/ppbus/ppbus_io.h>
116 #include <dev/ppbus/ppbus_var.h>
117 
118 #include <machine/types.h>
119 #include <sys/intr.h>
120 
121 #ifndef LPMTU			/* MTU for the lp# interfaces */
122 #define	LPMTU		1500
123 #endif
124 
125 #ifndef LPMAXSPIN1		/* DELAY factor for the lp# interfaces */
126 #define	LPMAXSPIN1	8000	/* Spinning for remote intr to happen */
127 #endif
128 
129 #ifndef LPMAXSPIN2		/* DELAY factor for the lp# interfaces */
130 #define	LPMAXSPIN2	500	/* Spinning for remote handshake to happen */
131 #endif
132 
133 #ifndef LPMAXERRS		/* Max errors before !RUNNING */
134 #define	LPMAXERRS	100
135 #endif
136 
137 #ifndef LPMAXRTRY
138 #define LPMAXRTRY	100	/* If channel busy, retry LPMAXRTRY
139 					consecutive times */
140 #endif
141 
142 #define CLPIPHDRLEN	14	/* We send dummy ethernet addresses (two) + packet type in front of packet */
143 #define	CLPIP_SHAKE	0x80	/* This bit toggles between nibble reception */
144 #define MLPIPHDRLEN	CLPIPHDRLEN
145 
146 #define LPIPHDRLEN	2	/* We send 0x08, 0x00 in front of packet */
147 #define	LPIP_SHAKE	0x40	/* This bit toggles between nibble reception */
148 #if !defined(MLPIPHDRLEN) || LPIPHDRLEN > MLPIPHDRLEN
149 #define MLPIPHDRLEN	LPIPHDRLEN
150 #endif
151 
152 #define	LPIPTBLSIZE	256	/* Size of octet translation table */
153 
154 #define LP_PRINTF	if (lpflag) printf
155 
156 #ifdef PLIP_DEBUG
157 static int volatile lpflag = 1;
158 #else
159 static int volatile lpflag = 0;
160 #endif
161 
162 /* Tx/Rsv 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 static u_char *ctxmith;
168 #define ctxmitl (ctxmith+(1*LPIPTBLSIZE))
169 #define ctrecvh (ctxmith+(2*LPIPTBLSIZE))
170 #define ctrecvl (ctxmith+(3*LPIPTBLSIZE))
171 static uint16_t lp_count = 0;
172 
173 /* Autoconf functions */
174 static int lp_probe(device_t, cfdata_t, void *);
175 static void lp_attach(device_t, device_t, void *);
176 static int lp_detach(device_t, int);
177 
178 /* Soft config data */
179 struct lp_softc {
180 	struct ppbus_device_softc ppbus_dev;
181 	struct ifnet sc_if;
182 	u_char *sc_ifbuf;
183 	unsigned short sc_iferrs;
184 	unsigned short sc_xmit_rtry;
185 	u_int8_t sc_dev_ok; /* Zero means ok */
186 };
187 
188 /* Autoconf structure */
189 CFATTACH_DECL_NEW(plip, sizeof(struct lp_softc), lp_probe, lp_attach, lp_detach,
190 	NULL);
191 
192 /* Functions for the lp interface */
193 static void lpinittables(void);
194 static void lpfreetables(void);
195 static int lpioctl(struct ifnet *, u_long, void *);
196 static int lpoutput(struct ifnet *, struct mbuf *, const struct sockaddr *,
197     const struct rtentry *);
198 static void lpstart(struct ifnet *);
199 static void lp_intr(void *);
200 
201 
202 static int
203 lp_probe(device_t parent, cfdata_t match, void *aux)
204 {
205 	struct ppbus_attach_args * args = aux;
206 
207 	/* Fail if ppbus is not interrupt capable */
208 	if (args->capabilities & PPBUS_HAS_INTR)
209 		return 1;
210 
211 	printf("%s(%s): not an interrupt-driven port.\n", __func__,
212 		device_xname(parent));
213 	return 0;
214 }
215 
216 static void
217 lp_attach(device_t parent, device_t self, void *aux)
218 {
219 	struct lp_softc * lp = device_private(self);
220 	struct ifnet * ifp = &lp->sc_if;
221 
222 	lp->ppbus_dev.sc_dev = self;
223 	lp->sc_dev_ok = 0;
224 	lp->sc_ifbuf = NULL;
225 	lp->sc_iferrs = 0;
226 	lp->sc_xmit_rtry = 0;
227 
228 	ifp->if_softc = lp;
229 	strlcpy(ifp->if_xname, device_xname(self), IFNAMSIZ);
230 	ifp->if_mtu = LPMTU;
231 	ifp->if_flags = IFF_SIMPLEX | IFF_POINTOPOINT | IFF_MULTICAST;
232 	ifp->if_ioctl = lpioctl;
233 	ifp->if_output = lpoutput;
234 	ifp->if_start = lpstart;
235 	ifp->if_type = IFT_PARA;
236 	ifp->if_hdrlen = 0;
237 	ifp->if_addrlen = 0;
238 	ifp->if_dlt = DLT_NULL;
239 	IFQ_SET_MAXLEN(&ifp->if_snd, IFQ_MAXLEN);
240 	IFQ_SET_READY(&ifp->if_snd);
241 	if_attach(ifp);
242 	if_alloc_sadl(ifp);
243 
244 	bpf_attach(ifp, DLT_NULL, sizeof(u_int32_t));
245 
246 	if (lp_count++ == 0)
247 		lpinittables();
248 	printf("\n");
249 }
250 
251 static int
252 lp_detach(device_t self, int flags)
253 {
254 	int error = 0;
255 	struct lp_softc * lp = device_private(self);
256 	device_t ppbus = device_parent(self);
257 
258 	if (lp->sc_dev_ok) {
259 		if (!(flags & DETACH_QUIET))
260 			LP_PRINTF("%s(%s): device not properly attached! "
261 				"Skipping detach....\n", __func__,
262 				device_xname(self));
263 		return error;
264 	}
265 
266 	/* If interface is up, bring it down and release ppbus */
267 	if (lp->sc_if.if_flags & IFF_RUNNING) {
268 		ppbus_wctr(ppbus, 0x00);
269 		if_detach(&lp->sc_if);
270 		error = ppbus_remove_handler(ppbus, lp_intr);
271 		if (error) {
272 			if (!(flags & DETACH_QUIET))
273 				LP_PRINTF("%s(%s): unable to remove interrupt "
274 					"callback.\n", __func__,
275 					device_xname(self));
276 			if (!(flags & DETACH_FORCE))
277 				return error;
278 		}
279 		error = ppbus_release_bus(ppbus, self, 0, 0);
280 		if (error) {
281 			if (!(flags & DETACH_QUIET))
282 				LP_PRINTF("%s(%s): error releasing bus %s.\n",
283 					__func__, device_xname(self),
284 					device_xname(ppbus));
285 			if (!(flags & DETACH_FORCE))
286 				return error;
287 		}
288 	}
289 
290 	if (lp->sc_ifbuf)
291 		free(lp->sc_ifbuf, M_DEVBUF);
292 
293 	if (--lp_count == 0)
294 		lpfreetables();
295 	return error;
296 }
297 
298 /*
299  * Build the translation tables for the LPIP (BSD unix) protocol.
300  * We don't want to calculate these nasties in our tight loop, so we
301  * precalculate them when we initialize.
302  */
303 static void
304 lpinittables(void)
305 {
306 	int i;
307 
308 	if (!txmith)
309 		txmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
310 
311 	if (!ctxmith)
312 		ctxmith = malloc(4*LPIPTBLSIZE, M_DEVBUF, M_WAITOK);
313 
314 	for (i = 0; i < LPIPTBLSIZE; i++) {
315 		ctxmith[i] = (i & 0xF0) >> 4;
316 		ctxmitl[i] = 0x10 | (i & 0x0F);
317 		ctrecvh[i] = (i & 0x78) << 1;
318 		ctrecvl[i] = (i & 0x78) >> 3;
319 	}
320 
321 	for (i = 0; i < LPIPTBLSIZE; i++) {
322 		txmith[i] = ((i & 0x80) >> 3) | ((i & 0x70) >> 4) | 0x08;
323 		txmitl[i] = ((i & 0x08) << 1) | (i & 0x07);
324 		trecvh[i] = ((~i) & 0x80) | ((i & 0x38) << 1);
325 		trecvl[i] = (((~i) & 0x80) >> 4) | ((i & 0x38) >> 3);
326 	}
327 }
328 
329 /* Free translation tables */
330 static void
331 lpfreetables(void)
332 {
333 	if (txmith)
334 		free(txmith, M_DEVBUF);
335 	if (ctxmith)
336 		free(ctxmith, M_DEVBUF);
337 	txmith = ctxmith = NULL;
338 }
339 
340 
341 /* Process an ioctl request. */
342 static int
343 lpioctl(struct ifnet *ifp, u_long cmd, void *data)
344 {
345 	struct lp_softc * sc = ifp->if_softc;
346 	device_t dev = sc->ppbus_dev.sc_dev;
347 	device_t ppbus = device_parent(dev);
348 	struct ifaddr * ifa = (struct ifaddr *)data;
349 	struct ifreq * ifr = (struct ifreq *)data;
350 	u_char * ptr;
351 	int error, s;
352 
353 	error = 0;
354 	s = splnet();
355 
356 	if (sc->sc_dev_ok) {
357 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
358 			device_xname(dev));
359 		error = ENODEV;
360 		goto end;
361 	}
362 
363 	switch (cmd) {
364 
365 	case SIOCSIFDSTADDR:
366 		if (ifa->ifa_addr->sa_family != AF_INET)
367 			error = EAFNOSUPPORT;
368 		break;
369 
370 	case SIOCINITIFADDR:
371 		if (ifa->ifa_addr->sa_family != AF_INET) {
372 			error = EAFNOSUPPORT;
373 			break;
374 		}
375 		ifp->if_flags |= IFF_UP;
376 	/* FALLTHROUGH */
377 	case SIOCSIFFLAGS:
378 		if (cmd == SIOCSIFFLAGS) {
379 			if ((error = ifioctl_common(ifp, cmd, data)) != 0)
380 				break;
381 		}
382 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == IFF_UP) {
383 			if ((error = ppbus_request_bus(ppbus, dev, 0, 0)))
384 				break;
385 			error = ppbus_set_mode(ppbus, PPBUS_COMPATIBLE, 0);
386 			if (error)
387 				break;
388 
389 			error = ppbus_add_handler(ppbus, lp_intr, dev);
390 			if (error) {
391 				LP_PRINTF("%s(%s): unable to register interrupt"
392 					" callback.\n", __func__,
393 					device_xname(dev));
394 				ppbus_release_bus(ppbus, dev, 0, 0);
395 				break;
396 			}
397 
398 			/* Allocate a buffer if necessary */
399 			if (sc->sc_ifbuf == NULL) {
400 				sc->sc_ifbuf = malloc(sc->sc_if.if_mtu +
401 					MLPIPHDRLEN, M_DEVBUF, M_WAITOK);
402 			}
403 
404 			ppbus_wctr(ppbus, IRQENABLE);
405 			ifp->if_flags |= IFF_RUNNING;
406 		}
407 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == IFF_RUNNING) {
408 			ppbus_remove_handler(ppbus, lp_intr);
409 			error = ppbus_release_bus(ppbus, dev, 0, 0);
410 			ifp->if_flags &= ~IFF_RUNNING;
411 		}
412 		/* Go quiescent */
413 		ppbus_wdtr(ppbus, 0);
414 		break;
415 
416 	case SIOCSIFMTU:
417 		if (sc->sc_if.if_mtu == ifr->ifr_mtu)
418 			break;
419 		ptr = sc->sc_ifbuf;
420 		sc->sc_ifbuf = malloc(ifr->ifr_mtu + MLPIPHDRLEN, M_DEVBUF,
421 			M_WAITOK);
422 		if (ptr)
423 			free(ptr,M_DEVBUF);
424 		/*FALLTHROUGH*/
425 	case SIOCGIFMTU:
426 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
427 			error = 0;
428 		break;
429 
430 	case SIOCADDMULTI:
431 	case SIOCDELMULTI:
432 		if (ifr == NULL) {
433 			error = EAFNOSUPPORT;		/* XXX */
434 			break;
435 		}
436 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
437 		case AF_INET:
438 			break;
439 		default:
440 			splx(s);
441 			return EAFNOSUPPORT;
442 		}
443 		break;
444 
445 	case SIOCGIFMEDIA:
446 		/*
447 		 * No ifmedia support at this stage; maybe use it
448 		 * in future for eg. protocol selection.
449 		 */
450 	default:
451 		LP_PRINTF("LP:ioctl(0x%lx)\n", cmd);
452 		error = ifioctl_common(ifp, cmd, data);
453 	}
454 
455 end:
456 	splx(s);
457 	return error;
458 }
459 
460 static inline int
461 clpoutbyte(u_char byte, int spin, device_t ppbus)
462 {
463 	int s = spin;
464 	ppbus_wdtr(ppbus, ctxmitl[byte]);
465 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
466 		if (--s == 0) {
467 			return 1;
468 		}
469 	}
470 	s = spin;
471 	ppbus_wdtr(ppbus, ctxmith[byte]);
472 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
473 		if (--s == 0) {
474 			return 1;
475 		}
476 	}
477 	return 0;
478 }
479 
480 static inline int
481 clpinbyte(int spin, device_t ppbus)
482 {
483 	u_char c, cl;
484 	int s = spin;
485 
486 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
487 		if (!--s) {
488 			return -1;
489 		}
490 	}
491 	cl = ppbus_rstr(ppbus);
492 	ppbus_wdtr(ppbus, 0x10);
493 
494 	s = spin;
495 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
496 		if (!--s) {
497 			return -1;
498 		}
499 	}
500 	c = ppbus_rstr(ppbus);
501 	ppbus_wdtr(ppbus, 0x00);
502 
503 	return (ctrecvl[cl] | ctrecvh[c]);
504 }
505 
506 static void
507 lptap(struct ifnet *ifp, struct mbuf *m, u_int direction)
508 {
509 	/*
510 	 * Send a packet through bpf. We need to prepend the address family
511 	 * as a four byte field. Cons up a dummy header to pacify bpf. This
512 	 * is safe because bpf will only read from the mbuf (i.e., it won't
513 	 * try to free it or keep a pointer to it).
514 	 */
515 	u_int32_t af = AF_INET;
516 	struct mbuf m0;
517 
518 	m0.m_type = MT_DATA;
519 	m0.m_next = m;
520 	m0.m_nextpkt = NULL;
521 	m0.m_owner = NULL;
522 	m0.m_len = sizeof(u_int32_t);
523 	m0.m_data = (char *)&af;
524 	m0.m_flags = 0;
525 	bpf_mtap(ifp, &m0, direction);
526 }
527 
528 /* Soft interrupt handler called by hardware interrupt handler */
529 static void
530 lp_intr(void *arg)
531 {
532 	device_t dev = (device_t)arg;
533         device_t ppbus = device_parent(dev);
534 	struct lp_softc * sc = device_private(dev);
535 	struct ifnet * ifp = &sc->sc_if;
536 	struct mbuf *top;
537 	int len, s, j;
538 	u_char *bp;
539 	u_char c, cl;
540 
541 	s = splnet();
542 
543 	/* Do nothing if device not properly attached */
544 	if (sc->sc_dev_ok) {
545 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
546 			device_xname(dev));
547 		goto done;
548 	}
549 
550 	/* Do nothing if interface is not up */
551 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
552 		goto done;
553 
554 	/* If other side is no longer transmitting, do nothing */
555 	if (!(ppbus_rstr(ppbus) & LPIP_SHAKE))
556 		goto done;
557 
558 	/* Disable interrupts until we finish */
559 	ppbus_wctr(ppbus, ~IRQENABLE);
560 
561 	top = NULL;
562 	bp = sc->sc_ifbuf;
563 	/* Linux/crynwyr protocol receiving */
564 	if (ifp->if_flags & IFF_LINK0) {
565 		/* Ack. the request */
566 		ppbus_wdtr(ppbus, 0x01);
567 
568 		/* Get the packet length */
569 		j = clpinbyte(LPMAXSPIN2, ppbus);
570 		if (j == -1)
571 			goto err;
572 		len = j;
573 		j = clpinbyte(LPMAXSPIN2, ppbus);
574 		if (j == -1)
575 			goto err;
576 		len = len + (j << 8);
577 		if (len > ifp->if_mtu + MLPIPHDRLEN)
578 			goto err;
579 
580 		while (len--) {
581 			j = clpinbyte(LPMAXSPIN2, ppbus);
582 			if (j == -1) {
583 				goto err;
584 			}
585 			*bp++ = j;
586 		}
587 		/* Get and ignore checksum */
588 		j = clpinbyte(LPMAXSPIN2, ppbus);
589 		if (j == -1) {
590 			goto err;
591 		}
592 
593 		/* Return to idle state */
594 		ppbus_wdtr(ppbus, 0);
595 		len = bp - sc->sc_ifbuf;
596 		if (len <= CLPIPHDRLEN)
597 			goto err;
598 		len -= CLPIPHDRLEN;
599 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, ifp);
600 	}
601 	/* FreeBSD protocol receiving */
602 	else {
603 		len = ifp->if_mtu + LPIPHDRLEN;
604 		while (len--) {
605 			cl = ppbus_rstr(ppbus);
606 			ppbus_wdtr(ppbus, 0x08);
607 
608 			j = LPMAXSPIN2;
609 			while ((ppbus_rstr(ppbus) & LPIP_SHAKE)) {
610 				if (!--j)
611 					goto err;
612 			}
613 
614 			c = ppbus_rstr(ppbus);
615 			ppbus_wdtr(ppbus, 0);
616 
617 			*bp++= trecvh[cl] | trecvl[c];
618 
619 			j = LPMAXSPIN2;
620 			while (!((cl = ppbus_rstr(ppbus)) & LPIP_SHAKE)) {
621 				if (cl != c &&
622 					(((cl = ppbus_rstr(ppbus)) ^ 0xb8) &
623 					0xf8) == (c & 0xf8))
624 					goto end;
625 				if (!--j)
626 					goto err;
627 			}
628 		}
629 
630 end:
631 		len = bp - sc->sc_ifbuf;
632 		if (len <= LPIPHDRLEN)
633 			goto err;
634 		len -= LPIPHDRLEN;
635 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, ifp);
636 	}
637 
638 	if (top == NULL) {
639 		if_statinc(ifp, if_iqdrops);
640 		goto err;
641 	}
642 	if (ifp->if_bpf) {
643 		lptap(ifp, top, BPF_D_IN);
644 	}
645 	if (__predict_false(!pktq_enqueue(ip_pktq, top, 0))) {
646 		if_statinc(ifp, if_iqdrops);
647 		m_freem(top);
648 		goto err;
649 	}
650 	if_statinc(ifp, if_ipackets);
651 	if_statadd(ifp, if_ibytes, len);
652 	sc->sc_iferrs = 0;
653 
654 	goto done;
655 
656 err:
657 	/* Return to idle state */
658 	ppbus_wdtr(ppbus, 0);
659 	if_statinc(ifp, if_ierrors);
660 	sc->sc_iferrs++;
661 	LP_PRINTF("R");
662 	/* Disable interface if there are too many errors */
663 	if (sc->sc_iferrs > LPMAXERRS) {
664 		aprint_error_dev(dev, "Too many consecutive errors, going off-line.\n");
665 		ppbus_wctr(ppbus, ~IRQENABLE);
666 		if_down(ifp);
667 		sc->sc_iferrs = 0;
668 	}
669 
670 done:
671 	/* Re-enable interrupts */
672 	ppbus_wctr(ppbus, IRQENABLE);
673 	/* If interface is not active, send some packets */
674 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
675 		lpstart(ifp);
676 	splx(s);
677 	return;
678 }
679 
680 static inline int
681 lpoutbyte(u_char byte, int spin, device_t ppbus)
682 {
683 	int s = spin;
684 	ppbus_wdtr(ppbus, txmith[byte]);
685 	while (!(ppbus_rstr(ppbus) & LPIP_SHAKE)) {
686 		if (--s == 0)
687 			return 1;
688 	}
689 	s = spin;
690 	ppbus_wdtr(ppbus, txmitl[byte]);
691 	while (ppbus_rstr(ppbus) & LPIP_SHAKE) {
692 		if (--s == 0)
693 			return 1;
694 	}
695 	return 0;
696 }
697 
698 /* Queue a packet for delivery */
699 static int
700 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
701     const struct rtentry *rt)
702 {
703 	struct lp_softc * sc = ifp->if_softc;
704 	device_t dev = sc->ppbus_dev.sc_dev;
705 	device_t ppbus = device_parent(dev);
706 	int err;
707 	int s;
708 
709 	s = splnet();
710 
711 	if (sc->sc_dev_ok) {
712 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
713 			device_xname(dev));
714 		err = ENODEV;
715 		goto endoutput;
716 	}
717 
718 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
719 		err = ENETDOWN;
720 		goto endoutput;
721 	}
722 
723 	/* Only support INET */
724 	if (dst->sa_family != AF_INET) {
725 		LP_PRINTF("%s: af%d not supported\n", ifp->if_xname,
726 		    dst->sa_family);
727 		if_statinc(ifp, if_noproto);
728 		err = EAFNOSUPPORT;
729 		goto endoutput;
730 	}
731 
732 	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
733 	IFQ_ENQUEUE(&ifp->if_snd, m, err);
734 	if (err == 0) {
735 		if ((ifp->if_flags & IFF_OACTIVE) == 0)
736 			lpstart(ifp);
737 	} else {
738 		if_statinc(ifp, if_oerrors);
739 		sc->sc_iferrs++;
740 		LP_PRINTF("Q");
741 
742 		/* Disable interface if there are too many errors */
743 		if (sc->sc_iferrs > LPMAXERRS) {
744 			aprint_error_dev(dev, "Too many errors, going off-line.\n");
745 			ppbus_wctr(ppbus, ~IRQENABLE);
746 			if_down(ifp);
747 			sc->sc_iferrs = 0;
748 		}
749 	}
750 
751 endoutput:
752 	if ((err != 0) && (err != ENOBUFS))
753 		m_freem(m);
754 	splx(s);
755 	return err;
756 }
757 
758 /* Send routine: send packets over PLIP cable. Call at splnet(). */
759 void
760 lpstart(struct ifnet * ifp)
761 {
762 	struct lp_softc * lp = ifp->if_softc;
763 	device_t dev = lp->ppbus_dev.sc_dev;
764 	device_t ppbus = device_parent(dev);
765 	struct mbuf * mm;
766 	struct mbuf * m;
767 	u_char * cp;
768 	int err, i, len, spin, count;
769 	u_char str, chksum;
770 
771 	if (lp->sc_dev_ok) {
772 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
773 			device_xname(dev));
774 		return;
775 	}
776 
777 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
778 		return;
779 	}
780 
781 	ifp->if_flags |= IFF_OACTIVE;
782 
783 	/* Go quiescent */
784 	ppbus_wdtr(ppbus, 0);
785 
786 	/* Output loop */
787 	for (;;) {
788 		/* Check if there are packets to send */
789 		if (IFQ_IS_EMPTY(&ifp->if_snd)) {
790 			goto final;
791 		}
792 		/* Try to send a packet, dequeue it later if successful */
793 		IFQ_POLL(&ifp->if_snd, m);
794 		if (m == NULL)
795 			goto final;
796 
797 		str = ppbus_rstr(ppbus);
798 		/* Wait until other side is not transmitting */
799 		if ((str & LPIP_SHAKE) ||
800 			((ifp->if_flags & IFF_LINK0) && !(str & CLPIP_SHAKE))) {
801 			LP_PRINTF("&");
802 			if (++lp->sc_xmit_rtry > LPMAXRTRY) {
803 				aprint_error_dev(dev, "Too many retries while channel "
804 					"busy, going off-line.\n");
805 				ppbus_wctr(ppbus, ~IRQENABLE);
806 				if_down(ifp);
807 				lp->sc_xmit_rtry = 0;
808 			}
809 			goto final;
810 		}
811 		lp->sc_xmit_rtry = 0;
812 
813 		/* Disable interrupt generation */
814 		ppbus_wctr(ppbus, ~IRQENABLE);
815 
816 		err = 1;
817 
818 		/* Output packet for Linux/crynwyr compatible protocol */
819 		if (ifp->if_flags & IFF_LINK0) {
820 			/* Calculate packet length */
821 			count = 14;		/* Ethernet header len */
822 			for (mm = m; mm; mm = mm->m_next) {
823 				count += mm->m_len;
824 			}
825 
826 			/* Alert other end to pending packet */
827 			spin = LPMAXSPIN1;
828 			ppbus_wdtr(ppbus, 0x08);
829 			while ((ppbus_rstr(ppbus) & 0x08) == 0) {
830 				if (--spin == 0) {
831 					goto nend;
832 				}
833 			}
834 
835 			if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
836 				goto nend;
837 			if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
838 				goto nend;
839 
840 			/* Send dummy ethernet header */
841 			chksum = 0;
842 			for (i = 0; i < 12; i++) {
843 				if (clpoutbyte(i, LPMAXSPIN1, ppbus))
844 					goto nend;
845 				chksum += i;
846 			}
847 
848 			if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
849 				goto nend;
850 			if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
851 				goto nend;
852 			chksum += 0x08 + 0x00;		/* Add into checksum */
853 
854 			mm = m;
855 			do {
856 				cp = mtod(mm, u_char *);
857 				len = mm->m_len;
858 				while (len--) {
859 					if (clpoutbyte(*cp, LPMAXSPIN2, ppbus))
860 						goto nend;
861 					chksum += *cp++;
862 				}
863 			} while ((mm = mm->m_next));
864 
865 			/* Send checksum */
866 			if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
867 				goto nend;
868 
869 			/* No errors */
870 			err = 0;
871 			/* Go quiescent */
872 			ppbus_wdtr(ppbus, 0);
873 		}
874 		/* Output packet for FreeBSD compatible protocol */
875 		else {
876 			/* We need a sensible value if we abort */
877 			cp = NULL;
878 
879 			if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
880 				goto end;
881 			if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
882 				goto end;
883 
884 			mm = m;
885 			do {
886 				cp = mtod(mm,u_char *);
887 				len = mm->m_len;
888 				while (len--)
889 					if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
890 						goto end;
891 			} while ((mm = mm->m_next));
892 
893 			/* no errors were encountered */
894 			err = 0;
895 
896 end:
897 			if (cp)
898 				ppbus_wdtr(ppbus, txmitl[*(--cp)] ^ 0x17);
899 			else
900 				ppbus_wdtr(ppbus, txmitl['\0'] ^ 0x17);
901 		}
902 
903 nend:
904 		/* Re-enable interrupt generation */
905 		ppbus_wctr(ppbus, IRQENABLE);
906 
907 		if (err) {
908 			/* Go quiescent */
909 			ppbus_wdtr(ppbus, 0);
910 
911 			if_statinc(ifp, if_oerrors);
912 			lp->sc_iferrs++;
913 			LP_PRINTF("X");
914 
915 			/* Disable interface if there are too many errors */
916 			if (lp->sc_iferrs > LPMAXERRS) {
917 				aprint_error_dev(dev, "Too many errors, going off-line.\n");
918 				ppbus_wctr(ppbus, ~IRQENABLE);
919 				if_down(ifp);
920 				lp->sc_iferrs = 0;
921 				goto final;
922 			}
923 		} else {
924 			/* Dequeue packet on success */
925 			IFQ_DEQUEUE(&ifp->if_snd, m);
926 			if(ifp->if_bpf)
927 				lptap(ifp, m, BPF_D_OUT);
928 			if_statinc(ifp, if_opackets);
929 			if_statadd(ifp, if_obytes, m->m_pkthdr.len);
930 			m_freem(m);
931 		}
932 	}
933 
934 final:
935 	ifp->if_flags &= ~IFF_OACTIVE;
936 	return;
937 }
938