xref: /netbsd-src/sys/dev/ppbus/if_plip.c (revision f3cfa6f6ce31685c6c4a758bc430e69eb99f50a4)
1 /* $NetBSD: if_plip.c,v 1.33 2018/11/15 10:56:30 maxv 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 1.33 2018/11/15 10:56:30 maxv 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_NOWAIT);
402 				if (!sc->sc_ifbuf) {
403 					error = ENOBUFS;
404 					ppbus_release_bus(ppbus, dev, 0, 0);
405 					break;
406 				}
407 			}
408 
409 			ppbus_wctr(ppbus, IRQENABLE);
410 			ifp->if_flags |= IFF_RUNNING;
411 		}
412 		if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) == IFF_RUNNING) {
413 			ppbus_remove_handler(ppbus, lp_intr);
414 			error = ppbus_release_bus(ppbus, dev, 0, 0);
415 			ifp->if_flags &= ~IFF_RUNNING;
416 		}
417 		/* Go quiescent */
418 		ppbus_wdtr(ppbus, 0);
419 		break;
420 
421 	case SIOCSIFMTU:
422 		if (sc->sc_if.if_mtu == ifr->ifr_mtu)
423 			break;
424 		ptr = sc->sc_ifbuf;
425 		sc->sc_ifbuf = malloc(ifr->ifr_mtu+MLPIPHDRLEN, M_DEVBUF,
426 			M_NOWAIT);
427 		if (!sc->sc_ifbuf) {
428 			sc->sc_ifbuf = ptr;
429 			error = ENOBUFS;
430 			break;
431 		}
432 		if (ptr)
433 			free(ptr,M_DEVBUF);
434 		/*FALLTHROUGH*/
435 	case SIOCGIFMTU:
436 		if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
437 			error = 0;
438 		break;
439 
440 	case SIOCADDMULTI:
441 	case SIOCDELMULTI:
442 		if (ifr == NULL) {
443 			error = EAFNOSUPPORT;		/* XXX */
444 			break;
445 		}
446 		switch (ifreq_getaddr(cmd, ifr)->sa_family) {
447 		case AF_INET:
448 			break;
449 		default:
450 			splx(s);
451 			return EAFNOSUPPORT;
452 		}
453 		break;
454 
455 	case SIOCGIFMEDIA:
456 		/*
457 		 * No ifmedia support at this stage; maybe use it
458 		 * in future for eg. protocol selection.
459 		 */
460 	default:
461 		LP_PRINTF("LP:ioctl(0x%lx)\n", cmd);
462 		error = ifioctl_common(ifp, cmd, data);
463 	}
464 
465 end:
466 	splx(s);
467 	return error;
468 }
469 
470 static inline int
471 clpoutbyte(u_char byte, int spin, device_t ppbus)
472 {
473 	int s = spin;
474 	ppbus_wdtr(ppbus, ctxmitl[byte]);
475 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
476 		if (--s == 0) {
477 			return 1;
478 		}
479 	}
480 	s = spin;
481 	ppbus_wdtr(ppbus, ctxmith[byte]);
482 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
483 		if (--s == 0) {
484 			return 1;
485 		}
486 	}
487 	return 0;
488 }
489 
490 static inline int
491 clpinbyte(int spin, device_t ppbus)
492 {
493 	u_char c, cl;
494 	int s = spin;
495 
496 	while (ppbus_rstr(ppbus) & CLPIP_SHAKE) {
497 		if (!--s) {
498 			return -1;
499 		}
500 	}
501 	cl = ppbus_rstr(ppbus);
502 	ppbus_wdtr(ppbus, 0x10);
503 
504 	s = spin;
505 	while (!(ppbus_rstr(ppbus) & CLPIP_SHAKE)) {
506 		if (!--s) {
507 			return -1;
508 		}
509 	}
510 	c = ppbus_rstr(ppbus);
511 	ppbus_wdtr(ppbus, 0x00);
512 
513 	return (ctrecvl[cl] | ctrecvh[c]);
514 }
515 
516 static void
517 lptap(struct ifnet *ifp, struct mbuf *m, u_int direction)
518 {
519 	/*
520 	 * Send a packet through bpf. We need to prepend the address family
521 	 * as a four byte field. Cons up a dummy header to pacify bpf. This
522 	 * is safe because bpf will only read from the mbuf (i.e., it won't
523 	 * try to free it or keep a pointer to it).
524 	 */
525 	u_int32_t af = AF_INET;
526 	struct mbuf m0;
527 
528 	m0.m_type = MT_DATA;
529 	m0.m_next = m;
530 	m0.m_nextpkt = NULL;
531 	m0.m_owner = NULL;
532 	m0.m_len = sizeof(u_int32_t);
533 	m0.m_data = (char *)&af;
534 	m0.m_flags = 0;
535 	bpf_mtap(ifp, &m0, direction);
536 }
537 
538 /* Soft interrupt handler called by hardware interrupt handler */
539 static void
540 lp_intr(void *arg)
541 {
542 	device_t dev = (device_t)arg;
543         device_t ppbus = device_parent(dev);
544 	struct lp_softc * sc = device_private(dev);
545 	struct ifnet * ifp = &sc->sc_if;
546 	struct mbuf *top;
547 	int len, s, j;
548 	u_char *bp;
549 	u_char c, cl;
550 
551 	s = splnet();
552 
553 	/* Do nothing if device not properly attached */
554 	if (sc->sc_dev_ok) {
555 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
556 			device_xname(dev));
557 		goto done;
558 	}
559 
560 	/* Do nothing if interface is not up */
561 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
562 		goto done;
563 
564 	/* If other side is no longer transmitting, do nothing */
565 	if (!(ppbus_rstr(ppbus) & LPIP_SHAKE))
566 		goto done;
567 
568 	/* Disable interrupts until we finish */
569 	ppbus_wctr(ppbus, ~IRQENABLE);
570 
571 	top = NULL;
572 	bp = sc->sc_ifbuf;
573 	/* Linux/crynwyr protocol receiving */
574 	if (ifp->if_flags & IFF_LINK0) {
575 		/* Ack. the request */
576 		ppbus_wdtr(ppbus, 0x01);
577 
578 		/* Get the packet length */
579 		j = clpinbyte(LPMAXSPIN2, ppbus);
580 		if (j == -1)
581 			goto err;
582 		len = j;
583 		j = clpinbyte(LPMAXSPIN2, ppbus);
584 		if (j == -1)
585 			goto err;
586 		len = len + (j << 8);
587 		if (len > ifp->if_mtu + MLPIPHDRLEN)
588 			goto err;
589 
590 		while (len--) {
591 			j = clpinbyte(LPMAXSPIN2, ppbus);
592 			if (j == -1) {
593 				goto err;
594 			}
595 			*bp++ = j;
596 		}
597 		/* Get and ignore checksum */
598 		j = clpinbyte(LPMAXSPIN2, ppbus);
599 		if (j == -1) {
600 			goto err;
601 		}
602 
603 		/* Return to idle state */
604 		ppbus_wdtr(ppbus, 0);
605 		len = bp - sc->sc_ifbuf;
606 		if (len <= CLPIPHDRLEN)
607 			goto err;
608 		len -= CLPIPHDRLEN;
609 		top = m_devget(sc->sc_ifbuf + CLPIPHDRLEN, len, 0, ifp);
610 	}
611 	/* FreeBSD protocol receiving */
612 	else {
613 		len = ifp->if_mtu + LPIPHDRLEN;
614 		while (len--) {
615 			cl = ppbus_rstr(ppbus);
616 			ppbus_wdtr(ppbus, 0x08);
617 
618 			j = LPMAXSPIN2;
619 			while ((ppbus_rstr(ppbus) & LPIP_SHAKE)) {
620 				if (!--j)
621 					goto err;
622 			}
623 
624 			c = ppbus_rstr(ppbus);
625 			ppbus_wdtr(ppbus, 0);
626 
627 			*bp++= trecvh[cl] | trecvl[c];
628 
629 			j = LPMAXSPIN2;
630 			while (!((cl = ppbus_rstr(ppbus)) & LPIP_SHAKE)) {
631 				if (cl != c &&
632 					(((cl = ppbus_rstr(ppbus)) ^ 0xb8) &
633 					0xf8) == (c & 0xf8))
634 					goto end;
635 				if (!--j)
636 					goto err;
637 			}
638 		}
639 
640 end:
641 		len = bp - sc->sc_ifbuf;
642 		if (len <= LPIPHDRLEN)
643 			goto err;
644 		len -= LPIPHDRLEN;
645 		top = m_devget(sc->sc_ifbuf + LPIPHDRLEN, len, 0, ifp);
646 	}
647 
648 	if (top == NULL) {
649 		ifp->if_iqdrops++;
650 		goto err;
651 	}
652 	if (ifp->if_bpf) {
653 		lptap(ifp, top, BPF_D_IN);
654 	}
655 	if (__predict_false(!pktq_enqueue(ip_pktq, top, 0))) {
656 		ifp->if_iqdrops++;
657 		m_freem(top);
658 		goto err;
659 	}
660 	ifp->if_ipackets++;
661 	ifp->if_ibytes += len;
662 	sc->sc_iferrs = 0;
663 
664 	goto done;
665 
666 err:
667 	/* Return to idle state */
668 	ppbus_wdtr(ppbus, 0);
669 	ifp->if_ierrors++;
670 	sc->sc_iferrs++;
671 	LP_PRINTF("R");
672 	/* Disable interface if there are too many errors */
673 	if (sc->sc_iferrs > LPMAXERRS) {
674 		aprint_error_dev(dev, "Too many consecutive errors, going off-line.\n");
675 		ppbus_wctr(ppbus, ~IRQENABLE);
676 		if_down(ifp);
677 		sc->sc_iferrs = 0;
678 	}
679 
680 done:
681 	/* Re-enable interrupts */
682 	ppbus_wctr(ppbus, IRQENABLE);
683 	/* If interface is not active, send some packets */
684 	if ((ifp->if_flags & IFF_OACTIVE) == 0)
685 		lpstart(ifp);
686 	splx(s);
687 	return;
688 }
689 
690 static inline int
691 lpoutbyte(u_char byte, int spin, device_t ppbus)
692 {
693 	int s = spin;
694 	ppbus_wdtr(ppbus, txmith[byte]);
695 	while (!(ppbus_rstr(ppbus) & LPIP_SHAKE)) {
696 		if (--s == 0)
697 			return 1;
698 	}
699 	s = spin;
700 	ppbus_wdtr(ppbus, txmitl[byte]);
701 	while (ppbus_rstr(ppbus) & LPIP_SHAKE) {
702 		if (--s == 0)
703 			return 1;
704 	}
705 	return 0;
706 }
707 
708 /* Queue a packet for delivery */
709 static int
710 lpoutput(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
711     const struct rtentry *rt)
712 {
713 	struct lp_softc * sc = ifp->if_softc;
714 	device_t dev = sc->ppbus_dev.sc_dev;
715 	device_t ppbus = device_parent(dev);
716 	int err;
717 	int s;
718 
719 	s = splnet();
720 
721 	if (sc->sc_dev_ok) {
722 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
723 			device_xname(dev));
724 		err = ENODEV;
725 		goto endoutput;
726 	}
727 
728 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
729 		err = ENETDOWN;
730 		goto endoutput;
731 	}
732 
733 	/* Only support INET */
734 	if (dst->sa_family != AF_INET) {
735 		LP_PRINTF("%s: af%d not supported\n", ifp->if_xname,
736 		    dst->sa_family);
737 		ifp->if_noproto++;
738 		err = EAFNOSUPPORT;
739 		goto endoutput;
740 	}
741 
742 	IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);
743 	IFQ_ENQUEUE(&ifp->if_snd, m, err);
744 	if (err == 0) {
745 		if ((ifp->if_flags & IFF_OACTIVE) == 0)
746 			lpstart(ifp);
747 	} else {
748 		ifp->if_oerrors++;
749 		sc->sc_iferrs++;
750 		LP_PRINTF("Q");
751 
752 		/* Disable interface if there are too many errors */
753 		if (sc->sc_iferrs > LPMAXERRS) {
754 			aprint_error_dev(dev, "Too many errors, going off-line.\n");
755 			ppbus_wctr(ppbus, ~IRQENABLE);
756 			if_down(ifp);
757 			sc->sc_iferrs = 0;
758 		}
759 	}
760 
761 endoutput:
762 	if ((err != 0) && (err != ENOBUFS))
763 		m_freem(m);
764 	splx(s);
765 	return err;
766 }
767 
768 /* Send routine: send packets over PLIP cable. Call at splnet(). */
769 void
770 lpstart(struct ifnet * ifp)
771 {
772 	struct lp_softc * lp = ifp->if_softc;
773 	device_t dev = lp->ppbus_dev.sc_dev;
774 	device_t ppbus = device_parent(dev);
775 	struct mbuf * mm;
776 	struct mbuf * m;
777 	u_char * cp;
778 	int err, i, len, spin, count;
779 	u_char str, chksum;
780 
781 	if (lp->sc_dev_ok) {
782 		LP_PRINTF("%s(%s): device not properly attached!", __func__,
783 			device_xname(dev));
784 		return;
785 	}
786 
787 	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
788 		return;
789 	}
790 
791 	ifp->if_flags |= IFF_OACTIVE;
792 
793 	/* Go quiescent */
794 	ppbus_wdtr(ppbus, 0);
795 
796 	/* Output loop */
797 	for (;;) {
798 		/* Check if there are packets to send */
799 		if (IFQ_IS_EMPTY(&ifp->if_snd)) {
800 			goto final;
801 		}
802 		/* Try to send a packet, dequeue it later if successful */
803 		IFQ_POLL(&ifp->if_snd, m);
804 		if (m == NULL)
805 			goto final;
806 
807 		str = ppbus_rstr(ppbus);
808 		/* Wait until other side is not transmitting */
809 		if ((str & LPIP_SHAKE) ||
810 			((ifp->if_flags & IFF_LINK0) && !(str & CLPIP_SHAKE))) {
811 			LP_PRINTF("&");
812 			if (++lp->sc_xmit_rtry > LPMAXRTRY) {
813 				aprint_error_dev(dev, "Too many retries while channel "
814 					"busy, going off-line.\n");
815 				ppbus_wctr(ppbus, ~IRQENABLE);
816 				if_down(ifp);
817 				lp->sc_xmit_rtry = 0;
818 			}
819 			goto final;
820 		}
821 		lp->sc_xmit_rtry = 0;
822 
823 		/* Disable interrupt generation */
824 		ppbus_wctr(ppbus, ~IRQENABLE);
825 
826 		err = 1;
827 
828 		/* Output packet for Linux/crynwyr compatible protocol */
829 		if (ifp->if_flags & IFF_LINK0) {
830 			/* Calculate packet length */
831 			count = 14;		/* Ethernet header len */
832 			for (mm = m; mm; mm = mm->m_next) {
833 				count += mm->m_len;
834 			}
835 
836 			/* Alert other end to pending packet */
837 			spin = LPMAXSPIN1;
838 			ppbus_wdtr(ppbus, 0x08);
839 			while ((ppbus_rstr(ppbus) & 0x08) == 0) {
840 				if (--spin == 0) {
841 					goto nend;
842 				}
843 			}
844 
845 			if (clpoutbyte(count & 0xFF, LPMAXSPIN1, ppbus))
846 				goto nend;
847 			if (clpoutbyte((count >> 8) & 0xFF, LPMAXSPIN1, ppbus))
848 				goto nend;
849 
850 			/* Send dummy ethernet header */
851 			chksum = 0;
852 			for (i = 0; i < 12; i++) {
853 				if (clpoutbyte(i, LPMAXSPIN1, ppbus))
854 					goto nend;
855 				chksum += i;
856 			}
857 
858 			if (clpoutbyte(0x08, LPMAXSPIN1, ppbus))
859 				goto nend;
860 			if (clpoutbyte(0x00, LPMAXSPIN1, ppbus))
861 				goto nend;
862 			chksum += 0x08 + 0x00;		/* Add into checksum */
863 
864 			mm = m;
865 			do {
866 				cp = mtod(mm, u_char *);
867 				len = mm->m_len;
868 				while (len--) {
869 					if (clpoutbyte(*cp, LPMAXSPIN2, ppbus))
870 						goto nend;
871 					chksum += *cp++;
872 				}
873 			} while ((mm = mm->m_next));
874 
875 			/* Send checksum */
876 			if (clpoutbyte(chksum, LPMAXSPIN2, ppbus))
877 				goto nend;
878 
879 			/* No errors */
880 			err = 0;
881 			/* Go quiescent */
882 			ppbus_wdtr(ppbus, 0);
883 		}
884 		/* Output packet for FreeBSD compatible protocol */
885 		else {
886 			/* We need a sensible value if we abort */
887 			cp = NULL;
888 
889 			if (lpoutbyte(0x08, LPMAXSPIN1, ppbus))
890 				goto end;
891 			if (lpoutbyte(0x00, LPMAXSPIN2, ppbus))
892 				goto end;
893 
894 			mm = m;
895 			do {
896 				cp = mtod(mm,u_char *);
897 				len = mm->m_len;
898 				while (len--)
899 					if (lpoutbyte(*cp++, LPMAXSPIN2, ppbus))
900 						goto end;
901 			} while ((mm = mm->m_next));
902 
903 			/* no errors were encountered */
904 			err = 0;
905 
906 end:
907 			if (cp)
908 				ppbus_wdtr(ppbus, txmitl[*(--cp)] ^ 0x17);
909 			else
910 				ppbus_wdtr(ppbus, txmitl['\0'] ^ 0x17);
911 		}
912 
913 nend:
914 		/* Re-enable interrupt generation */
915 		ppbus_wctr(ppbus, IRQENABLE);
916 
917 		if (err) {
918 			/* Go quiescent */
919 			ppbus_wdtr(ppbus, 0);
920 
921 			ifp->if_oerrors++;
922 			lp->sc_iferrs++;
923 			LP_PRINTF("X");
924 
925 			/* Disable interface if there are too many errors */
926 			if (lp->sc_iferrs > LPMAXERRS) {
927 				aprint_error_dev(dev, "Too many errors, going off-line.\n");
928 				ppbus_wctr(ppbus, ~IRQENABLE);
929 				if_down(ifp);
930 				lp->sc_iferrs = 0;
931 				goto final;
932 			}
933 		} else {
934 			/* Dequeue packet on success */
935 			IFQ_DEQUEUE(&ifp->if_snd, m);
936 			if(ifp->if_bpf)
937 				lptap(ifp, m, BPF_D_OUT);
938 			ifp->if_opackets++;
939 			ifp->if_obytes += m->m_pkthdr.len;
940 			m_freem(m);
941 		}
942 	}
943 
944 final:
945 	ifp->if_flags &= ~IFF_OACTIVE;
946 	return;
947 }
948