xref: /netbsd-src/sys/dev/ppbus/if_plip.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /* $NetBSD: if_plip.c,v 1.30 2018/06/26 06:48:02 msaitoh 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 1.30 2018/06/26 06:48:02 msaitoh 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 ((error = ifioctl_common(ifp, cmd, data)) != 0)
379 			break;
380 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == IFF_UP) {
381 			if ((error = ppbus_request_bus(ppbus, dev, 0, 0)))
382 				break;
383 			error = ppbus_set_mode(ppbus, PPBUS_COMPATIBLE, 0);
384 			if (error)
385 				break;
386 
387 			error = ppbus_add_handler(ppbus, lp_intr, dev);
388 			if (error) {
389 				LP_PRINTF("%s(%s): unable to register interrupt"
390 					" callback.\n", __func__,
391 					device_xname(dev));
392 				ppbus_release_bus(ppbus, dev, 0, 0);
393 				break;
394 			}
395 
396 			/* Allocate a buffer if necessary */
397 			if (sc->sc_ifbuf == NULL) {
398 				sc->sc_ifbuf = malloc(sc->sc_if.if_mtu +
399 					MLPIPHDRLEN, M_DEVBUF, M_NOWAIT);
400 				if (!sc->sc_ifbuf) {
401 					error = ENOBUFS;
402 					ppbus_release_bus(ppbus, dev, 0, 0);
403 					break;
404 				}
405 			}
406 
407 			ppbus_wctr(ppbus, IRQENABLE);
408 			ifp->if_flags |= IFF_RUNNING;
409 		}
410 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == IFF_RUNNING) {
411 			ppbus_remove_handler(ppbus, lp_intr);
412 			error = ppbus_release_bus(ppbus, dev, 0, 0);
413 			ifp->if_flags &= ~IFF_RUNNING;
414 		}
415 		/* Go quiescent */
416 		ppbus_wdtr(ppbus, 0);
417 		break;
418 
419 	case SIOCSIFMTU:
420 		if (sc->sc_if.if_mtu == ifr->ifr_mtu)
421 			break;
422 		ptr = sc->sc_ifbuf;
423 		sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF,
424 			M_NOWAIT);
425 		if (!sc->sc_ifbuf) {
426 			sc->sc_ifbuf = ptr;
427 			error = ENOBUFS;
428 			break;
429 		}
430 		if (ptr)
431 			free(ptr,M_DEVBUF);
432 		/*FALLTHROUGH*/
433 	case SIOCGIFMTU:
434 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
435 			error = 0;
436 		break;
437 
438 	case SIOCADDMULTI:
439 	case SIOCDELMULTI:
440 		if (ifr == NULL) {
441 			error = EAFNOSUPPORT;		/* XXX */
442 			break;
443 		}
444 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
445 		case AF_INET:
446 			break;
447 		default:
448 			splx(s);
449 			return EAFNOSUPPORT;
450 		}
451 		break;
452 
453 	case SIOCGIFMEDIA:
454 		/*
455 		 * No ifmedia support at this stage; maybe use it
456 		 * in future for eg. protocol selection.
457 		 */
458 	default:
459 		LP_PRINTF("LP:ioctl(0x%lx)\n", cmd);
460 		error = ifioctl_common(ifp, cmd, data);
461 	}
462 
463 end:
464 	splx(s);
465 	return error;
466 }
467 
468 static inline int
469 clpoutbyte(u_char byte, int spin, device_t ppbus)
470 {
471 	int s = spin;
472 	ppbus_wdtr(ppbus, ctxmitl[byte]);
473 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
474 		if (--s == 0) {
475 			return 1;
476 		}
477 	}
478 	s = spin;
479 	ppbus_wdtr(ppbus, ctxmith[byte]);
480 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
481 		if (--s == 0) {
482 			return 1;
483 		}
484 	}
485 	return 0;
486 }
487 
488 static inline int
489 clpinbyte(int spin, device_t ppbus)
490 {
491 	u_char c, cl;
492 	int s = spin;
493 
494 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
495 		if (!--s) {
496 			return -1;
497 		}
498 	}
499 	cl = ppbus_rstr(ppbus);
500 	ppbus_wdtr(ppbus, 0x10);
501 
502 	s = spin;
503 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
504 		if (!--s) {
505 			return -1;
506 		}
507 	}
508 	c = ppbus_rstr(ppbus);
509 	ppbus_wdtr(ppbus, 0x00);
510 
511 	return (ctrecvl[cl] | ctrecvh[c]);
512 }
513 
514 static void
515 lptap(struct ifnet *ifp, struct mbuf *m, u_int direction)
516 {
517 	/*
518 	 * Send a packet through bpf. We need to prepend the address family
519 	 * as a four byte field. Cons up a dummy header to pacify bpf. This
520 	 * is safe because bpf will only read from the mbuf (i.e., it won't
521 	 * try to free it or keep a pointer to it).
522 	 */
523 	u_int32_t af = AF_INET;
524 	struct mbuf m0;
525 
526 	m0.m_next = m;
527 	m0.m_len = sizeof(u_int32_t);
528 	m0.m_data = (char *)&af;
529 	bpf_mtap(ifp, &m0, direction);
530 }
531 
532 /* Soft interrupt handler called by hardware interrupt handler */
533 static void
534 lp_intr(void *arg)
535 {
536 	device_t dev = (device_t)arg;
537         device_t ppbus = device_parent(dev);
538 	struct lp_softc * sc = device_private(dev);
539 	struct ifnet * ifp = &sc->sc_if;
540 	struct mbuf *top;
541 	int len, s, j;
542 	u_char *bp;
543 	u_char c, cl;
544 
545 	s = splnet();
546 
547 	/* Do nothing if device not properly attached */
548 	if (sc->sc_dev_ok) {
549 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
550 			device_xname(dev));
551 		goto done;
552 	}
553 
554 	/* Do nothing if interface is not up */
555 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
556 		goto done;
557 
558 	/* If other side is no longer transmitting, do nothing */
559 	if (!(ppbus_rstr(ppbus) & LPIP_SHAKE))
560 		goto done;
561 
562 	/* Disable interrupts until we finish */
563 	ppbus_wctr(ppbus, ~IRQENABLE);
564 
565 	top = NULL;
566 	bp = sc->sc_ifbuf;
567 	/* Linux/crynwyr protocol receiving */
568 	if (ifp->if_flags & IFF_LINK0) {
569 		/* Ack. the request */
570 		ppbus_wdtr(ppbus, 0x01);
571 
572 		/* Get the packet length */
573 		j = clpinbyte(LPMAXSPIN2, ppbus);
574 		if (j == -1)
575 			goto err;
576 		len = j;
577 		j = clpinbyte(LPMAXSPIN2, ppbus);
578 		if (j == -1)
579 			goto err;
580 		len = len + (j << 8);
581 		if (len > ifp->if_mtu + MLPIPHDRLEN)
582 			goto err;
583 
584 		while (len--) {
585 			j = clpinbyte(LPMAXSPIN2, ppbus);
586 			if (j == -1) {
587 				goto err;
588 			}
589 			*bp++ = j;
590 		}
591 		/* Get and ignore checksum */
592 		j = clpinbyte(LPMAXSPIN2, ppbus);
593 		if (j == -1) {
594 			goto err;
595 		}
596 
597 		/* Return to idle state */
598 		ppbus_wdtr(ppbus, 0);
599 		len = bp - sc->sc_ifbuf;
600 		if (len <= CLPIPHDRLEN)
601 			goto err;
602 		len -= CLPIPHDRLEN;
603 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, ifp, NULL);
604 	}
605 	/* FreeBSD protocol receiving */
606 	else {
607 		len = ifp->if_mtu + LPIPHDRLEN;
608 		while (len--) {
609 			cl = ppbus_rstr(ppbus);
610 			ppbus_wdtr(ppbus, 0x08);
611 
612 			j = LPMAXSPIN2;
613 			while ((ppbus_rstr(ppbus) & LPIP_SHAKE)) {
614 				if (!--j)
615 					goto err;
616 			}
617 
618 			c = ppbus_rstr(ppbus);
619 			ppbus_wdtr(ppbus, 0);
620 
621 			*bp++= trecvh[cl] | trecvl[c];
622 
623 			j = LPMAXSPIN2;
624 			while (!((cl = ppbus_rstr(ppbus)) & LPIP_SHAKE)) {
625 				if (cl != c &&
626 					(((cl = ppbus_rstr(ppbus)) ^ 0xb8) &
627 					0xf8) == (c & 0xf8))
628 					goto end;
629 				if (!--j)
630 					goto err;
631 			}
632 		}
633 
634 end:
635 		len = bp - sc->sc_ifbuf;
636 		if (len <= LPIPHDRLEN)
637 			goto err;
638 		len -= LPIPHDRLEN;
639 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, ifp, NULL);
640 	}
641 
642 	if (top == NULL) {
643 		ifp->if_iqdrops++;
644 		goto err;
645 	}
646 	if (ifp->if_bpf) {
647 		lptap(ifp, top, BPF_D_IN);
648 	}
649 	if (__predict_false(!pktq_enqueue(ip_pktq, top, 0))) {
650 		ifp->if_iqdrops++;
651 		m_freem(top);
652 		goto err;
653 	}
654 	ifp->if_ipackets++;
655 	ifp->if_ibytes += len;
656 	sc->sc_iferrs = 0;
657 
658 	goto done;
659 
660 err:
661 	/* Return to idle state */
662 	ppbus_wdtr(ppbus, 0);
663 	ifp->if_ierrors++;
664 	sc->sc_iferrs++;
665 	LP_PRINTF("R");
666 	/* Disable interface if there are too many errors */
667 	if (sc->sc_iferrs > LPMAXERRS) {
668 		aprint_error_dev(dev, "Too many consecutive errors, going off-line.\n");
669 		ppbus_wctr(ppbus, ~IRQENABLE);
670 		if_down(ifp);
671 		sc->sc_iferrs = 0;
672 	}
673 
674 done:
675 	/* Re-enable interrupts */
676 	ppbus_wctr(ppbus, IRQENABLE);
677 	/* If interface is not active, send some packets */
678 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
679 		lpstart(ifp);
680 	splx(s);
681 	return;
682 }
683 
684 static inline int
685 lpoutbyte(u_char byte, int spin, device_t ppbus)
686 {
687 	int s = spin;
688 	ppbus_wdtr(ppbus, txmith[byte]);
689 	while (!(ppbus_rstr(ppbus) & LPIP_SHAKE)) {
690 		if (--s == 0)
691 			return 1;
692 	}
693 	s = spin;
694 	ppbus_wdtr(ppbus, txmitl[byte]);
695 	while (ppbus_rstr(ppbus) & LPIP_SHAKE) {
696 		if (--s == 0)
697 			return 1;
698 	}
699 	return 0;
700 }
701 
702 /* Queue a packet for delivery */
703 static int
704 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
705     const struct rtentry *rt)
706 {
707 	struct lp_softc * sc = ifp->if_softc;
708 	device_t dev = sc->ppbus_dev.sc_dev;
709 	device_t ppbus = device_parent(dev);
710 	int err;
711 	int s;
712 
713 	s = splnet();
714 
715 	if (sc->sc_dev_ok) {
716 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
717 			device_xname(dev));
718 		err = ENODEV;
719 		goto endoutput;
720 	}
721 
722 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
723 		err = ENETDOWN;
724 		goto endoutput;
725 	}
726 
727 	/* Only support INET */
728 	if (dst->sa_family != AF_INET) {
729 		LP_PRINTF("%s: af%d not supported\n", ifp->if_xname,
730 		    dst->sa_family);
731 		ifp->if_noproto++;
732 		err = EAFNOSUPPORT;
733 		goto endoutput;
734 	}
735 
736 	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
737 	IFQ_ENQUEUE(&ifp->if_snd, m, err);
738 	if (err == 0) {
739 		if ((ifp->if_flags & IFF_OACTIVE) == 0)
740 			lpstart(ifp);
741 	} else {
742 		ifp->if_oerrors++;
743 		sc->sc_iferrs++;
744 		LP_PRINTF("Q");
745 
746 		/* Disable interface if there are too many errors */
747 		if (sc->sc_iferrs > LPMAXERRS) {
748 			aprint_error_dev(dev, "Too many errors, going off-line.\n");
749 			ppbus_wctr(ppbus, ~IRQENABLE);
750 			if_down(ifp);
751 			sc->sc_iferrs = 0;
752 		}
753 	}
754 
755 endoutput:
756 	if ((err != 0) && (err != ENOBUFS))
757 		m_freem(m);
758 	splx(s);
759 	return err;
760 }
761 
762 /* Send routine: send packets over PLIP cable. Call at splnet(). */
763 void
764 lpstart(struct ifnet * ifp)
765 {
766 	struct lp_softc * lp = ifp->if_softc;
767 	device_t dev = lp->ppbus_dev.sc_dev;
768 	device_t ppbus = device_parent(dev);
769 	struct mbuf * mm;
770 	struct mbuf * m;
771 	u_char * cp;
772 	int err, i, len, spin, count;
773 	u_char str, chksum;
774 
775 	if (lp->sc_dev_ok) {
776 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
777 			device_xname(dev));
778 		return;
779 	}
780 
781 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
782 		return;
783 	}
784 
785 	ifp->if_flags |= IFF_OACTIVE;
786 
787 	/* Go quiescent */
788 	ppbus_wdtr(ppbus, 0);
789 
790 	/* Output loop */
791 	for (;;) {
792 		/* Check if there are packets to send */
793 		if (IFQ_IS_EMPTY(&ifp->if_snd)) {
794 			goto final;
795 		}
796 		/* Try to send a packet, dequeue it later if successful */
797 		IFQ_POLL(&ifp->if_snd, m);
798 		if (m == NULL)
799 			goto final;
800 
801 		str = ppbus_rstr(ppbus);
802 		/* Wait until other side is not transmitting */
803 		if ((str & LPIP_SHAKE) ||
804 			((ifp->if_flags & IFF_LINK0) && !(str & CLPIP_SHAKE))) {
805 			LP_PRINTF("&");
806 			if (++lp->sc_xmit_rtry > LPMAXRTRY) {
807 				aprint_error_dev(dev, "Too many retries while channel "
808 					"busy, going off-line.\n");
809 				ppbus_wctr(ppbus, ~IRQENABLE);
810 				if_down(ifp);
811 				lp->sc_xmit_rtry = 0;
812 			}
813 			goto final;
814 		}
815 		lp->sc_xmit_rtry = 0;
816 
817 		/* Disable interrupt generation */
818 		ppbus_wctr(ppbus, ~IRQENABLE);
819 
820 		err = 1;
821 
822 		/* Output packet for Linux/crynwyr compatible protocol */
823 		if (ifp->if_flags & IFF_LINK0) {
824 			/* Calculate packet length */
825 			count = 14;		/* Ethernet header len */
826 			for (mm = m; mm; mm = mm->m_next) {
827 				count += mm->m_len;
828 			}
829 
830 			/* Alert other end to pending packet */
831 			spin = LPMAXSPIN1;
832 			ppbus_wdtr(ppbus, 0x08);
833 			while ((ppbus_rstr(ppbus) & 0x08) == 0) {
834 				if (--spin == 0) {
835 					goto nend;
836 				}
837 			}
838 
839 			if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
840 				goto nend;
841 			if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
842 				goto nend;
843 
844 			/* Send dummy ethernet header */
845 			chksum = 0;
846 			for (i = 0; i < 12; i++) {
847 				if (clpoutbyte(i, LPMAXSPIN1, ppbus))
848 					goto nend;
849 				chksum += i;
850 			}
851 
852 			if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
853 				goto nend;
854 			if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
855 				goto nend;
856 			chksum += 0x08 + 0x00;		/* Add into checksum */
857 
858 			mm = m;
859 			do {
860 				cp = mtod(mm, u_char *);
861 				len = mm->m_len;
862 				while (len--) {
863 					if (clpoutbyte(*cp, LPMAXSPIN2, ppbus))
864 						goto nend;
865 					chksum += *cp++;
866 				}
867 			} while ((mm = mm->m_next));
868 
869 			/* Send checksum */
870 			if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
871 				goto nend;
872 
873 			/* No errors */
874 			err = 0;
875 			/* Go quiescent */
876 			ppbus_wdtr(ppbus, 0);
877 		}
878 		/* Output packet for FreeBSD compatible protocol */
879 		else {
880 			/* We need a sensible value if we abort */
881 			cp = NULL;
882 
883 			if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
884 				goto end;
885 			if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
886 				goto end;
887 
888 			mm = m;
889 			do {
890 				cp = mtod(mm,u_char *);
891 				len = mm->m_len;
892 				while (len--)
893 					if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
894 						goto end;
895 			} while ((mm = mm->m_next));
896 
897 			/* no errors were encountered */
898 			err = 0;
899 
900 end:
901 			if (cp)
902 				ppbus_wdtr(ppbus, txmitl[*(--cp)] ^ 0x17);
903 			else
904 				ppbus_wdtr(ppbus, txmitl['\0'] ^ 0x17);
905 		}
906 
907 nend:
908 		/* Re-enable interrupt generation */
909 		ppbus_wctr(ppbus, IRQENABLE);
910 
911 		if (err) {
912 			/* Go quiescent */
913 			ppbus_wdtr(ppbus, 0);
914 
915 			ifp->if_oerrors++;
916 			lp->sc_iferrs++;
917 			LP_PRINTF("X");
918 
919 			/* Disable interface if there are too many errors */
920 			if (lp->sc_iferrs > LPMAXERRS) {
921 				aprint_error_dev(dev, "Too many errors, going off-line.\n");
922 				ppbus_wctr(ppbus, ~IRQENABLE);
923 				if_down(ifp);
924 				lp->sc_iferrs = 0;
925 				goto final;
926 			}
927 		} else {
928 			/* Dequeue packet on success */
929 			IFQ_DEQUEUE(&ifp->if_snd, m);
930 			if(ifp->if_bpf)
931 				lptap(ifp, m, BPF_D_OUT);
932 			ifp->if_opackets++;
933 			ifp->if_obytes += m->m_pkthdr.len;
934 			m_freem(m);
935 		}
936 	}
937 
938 final:
939 	ifp->if_flags &= ~IFF_OACTIVE;
940 	return;
941 }
942