xref: /linux/drivers/net/hamradio/hdlcdrv.c (revision 54a8a2220c936a47840c9a3d74910c5a56fae2ed)
1 /*****************************************************************************/
2 
3 /*
4  *	hdlcdrv.c  -- HDLC packet radio network driver.
5  *
6  *	Copyright (C) 1996-2000  Thomas Sailer (sailer@ife.ee.ethz.ch)
7  *
8  *	This program is free software; you can redistribute it and/or modify
9  *	it under the terms of the GNU General Public License as published by
10  *	the Free Software Foundation; either version 2 of the License, or
11  *	(at your option) any later version.
12  *
13  *	This program is distributed in the hope that it will be useful,
14  *	but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *	GNU General Public License for more details.
17  *
18  *	You should have received a copy of the GNU General Public License
19  *	along with this program; if not, write to the Free Software
20  *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  *
22  *  Please note that the GPL allows you to use the driver, NOT the radio.
23  *  In order to use the radio, you need a license from the communications
24  *  authority of your country.
25  *
26  *  The driver was derived from Donald Beckers skeleton.c
27  *	Written 1993-94 by Donald Becker.
28  *
29  *  History:
30  *   0.1  21.09.1996  Started
31  *        18.10.1996  Changed to new user space access routines
32  *                    (copy_{to,from}_user)
33  *   0.2  21.11.1996  various small changes
34  *   0.3  03.03.1997  fixed (hopefully) IP not working with ax.25 as a module
35  *   0.4  16.04.1997  init code/data tagged
36  *   0.5  30.07.1997  made HDLC buffers bigger (solves a problem with the
37  *                    soundmodem driver)
38  *   0.6  05.04.1998  add spinlocks
39  *   0.7  03.08.1999  removed some old compatibility cruft
40  *   0.8  12.02.2000  adapted to softnet driver interface
41  */
42 
43 /*****************************************************************************/
44 
45 #include <linux/module.h>
46 #include <linux/types.h>
47 #include <linux/net.h>
48 #include <linux/in.h>
49 #include <linux/if.h>
50 #include <linux/slab.h>
51 #include <linux/errno.h>
52 #include <linux/init.h>
53 #include <linux/bitops.h>
54 
55 #include <linux/netdevice.h>
56 #include <linux/if_arp.h>
57 #include <linux/skbuff.h>
58 #include <linux/hdlcdrv.h>
59 #include <net/ax25.h>
60 #include <asm/uaccess.h>
61 
62 #include <linux/crc-ccitt.h>
63 
64 /* --------------------------------------------------------------------- */
65 
66 /*
67  * The name of the card. Is used for messages and in the requests for
68  * io regions, irqs and dma channels
69  */
70 
71 static char ax25_bcast[AX25_ADDR_LEN] =
72 {'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
73 static char ax25_nocall[AX25_ADDR_LEN] =
74 {'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};
75 
76 /* --------------------------------------------------------------------- */
77 
78 #define KISS_VERBOSE
79 
80 /* --------------------------------------------------------------------- */
81 
82 #define PARAM_TXDELAY   1
83 #define PARAM_PERSIST   2
84 #define PARAM_SLOTTIME  3
85 #define PARAM_TXTAIL    4
86 #define PARAM_FULLDUP   5
87 #define PARAM_HARDWARE  6
88 #define PARAM_RETURN    255
89 
90 /* --------------------------------------------------------------------- */
91 /*
92  * the CRC routines are stolen from WAMPES
93  * by Dieter Deyke
94  */
95 
96 
97 /*---------------------------------------------------------------------------*/
98 
99 static inline void append_crc_ccitt(unsigned char *buffer, int len)
100 {
101  	unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
102 	*buffer++ = crc;
103 	*buffer++ = crc >> 8;
104 }
105 
106 /*---------------------------------------------------------------------------*/
107 
108 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
109 {
110 	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
111 }
112 
113 /*---------------------------------------------------------------------------*/
114 
115 #if 0
116 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
117 {
118 	unsigned int crc = 0xffff;
119 
120 	for (; cnt > 0; cnt--)
121 		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
122 	crc ^= 0xffff;
123 	return (crc & 0xffff);
124 }
125 #endif
126 
127 /* ---------------------------------------------------------------------- */
128 
129 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
130 
131 /* ---------------------------------------------------------------------- */
132 /*
133  * The HDLC routines
134  */
135 
136 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
137 			     int num)
138 {
139 	int added = 0;
140 
141 	while (s->hdlcrx.rx_state && num >= 8) {
142 		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
143 			s->hdlcrx.rx_state = 0;
144 			return 0;
145 		}
146 		*s->hdlcrx.bp++ = bits >> (32-num);
147 		s->hdlcrx.len++;
148 		num -= 8;
149 		added += 8;
150 	}
151 	return added;
152 }
153 
154 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
155 {
156 	struct sk_buff *skb;
157 	int pkt_len;
158 	unsigned char *cp;
159 
160 	if (s->hdlcrx.len < 4)
161 		return;
162 	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
163 		return;
164 	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
165 	if (!(skb = dev_alloc_skb(pkt_len))) {
166 		printk("%s: memory squeeze, dropping packet\n", dev->name);
167 		s->stats.rx_dropped++;
168 		return;
169 	}
170 	cp = skb_put(skb, pkt_len);
171 	*cp++ = 0; /* KISS kludge */
172 	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
173 	skb->protocol = ax25_type_trans(skb, dev);
174 	netif_rx(skb);
175 	dev->last_rx = jiffies;
176 	s->stats.rx_packets++;
177 }
178 
179 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
180 {
181 	int i;
182 	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
183 
184 	if (!s || s->magic != HDLCDRV_MAGIC)
185 		return;
186 	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
187 		return;
188 
189 	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
190 		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
191 
192 #ifdef HDLCDRV_DEBUG
193 		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
194 #endif /* HDLCDRV_DEBUG */
195 	       	s->hdlcrx.bitstream >>= 16;
196 		s->hdlcrx.bitstream |= word << 16;
197 		s->hdlcrx.bitbuf >>= 16;
198 		s->hdlcrx.bitbuf |= word << 16;
199 		s->hdlcrx.numbits += 16;
200 		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
201 		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff;
202 		    i >= 0;
203 		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1,
204 		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
205 			if ((s->hdlcrx.bitstream & mask1) == mask1)
206 				s->hdlcrx.rx_state = 0; /* abort received */
207 			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
208 				/* flag received */
209 				if (s->hdlcrx.rx_state) {
210 					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
211 							  << (8+i),
212 							  s->hdlcrx.numbits
213 							  -8-i);
214 					hdlc_rx_flag(dev, s);
215 				}
216 				s->hdlcrx.len = 0;
217 				s->hdlcrx.bp = s->hdlcrx.buffer;
218 				s->hdlcrx.rx_state = 1;
219 				s->hdlcrx.numbits = i;
220 			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
221 				/* stuffed bit */
222 				s->hdlcrx.numbits--;
223 				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
224 					((s->hdlcrx.bitbuf & mask6) << 1);
225 			}
226 		}
227 		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
228 						       s->hdlcrx.numbits);
229 	}
230 	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
231 }
232 
233 /* ---------------------------------------------------------------------- */
234 
235 static inline void do_kiss_params(struct hdlcdrv_state *s,
236 				  unsigned char *data, unsigned long len)
237 {
238 
239 #ifdef KISS_VERBOSE
240 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
241 #else /* KISS_VERBOSE */
242 #define PKP(a,b)
243 #endif /* KISS_VERBOSE */
244 
245 	if (len < 2)
246 		return;
247 	switch(data[0]) {
248 	case PARAM_TXDELAY:
249 		s->ch_params.tx_delay = data[1];
250 		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
251 		break;
252 	case PARAM_PERSIST:
253 		s->ch_params.ppersist = data[1];
254 		PKP("p persistence = %u", s->ch_params.ppersist);
255 		break;
256 	case PARAM_SLOTTIME:
257 		s->ch_params.slottime = data[1];
258 		PKP("slot time = %ums", s->ch_params.slottime);
259 		break;
260 	case PARAM_TXTAIL:
261 		s->ch_params.tx_tail = data[1];
262 		PKP("TX tail = %ums", s->ch_params.tx_tail);
263 		break;
264 	case PARAM_FULLDUP:
265 		s->ch_params.fulldup = !!data[1];
266 		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
267 		break;
268 	default:
269 		break;
270 	}
271 #undef PKP
272 }
273 
274 /* ---------------------------------------------------------------------- */
275 
276 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
277 {
278 	unsigned int mask1, mask2, mask3;
279 	int i;
280 	struct sk_buff *skb;
281 	int pkt_len;
282 
283 	if (!s || s->magic != HDLCDRV_MAGIC)
284 		return;
285 	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
286 		return;
287 	for (;;) {
288 		if (s->hdlctx.numbits >= 16) {
289 			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
290 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
291 				return;
292 			}
293 			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
294 			s->hdlctx.bitbuf >>= 16;
295 			s->hdlctx.numbits -= 16;
296 		}
297 		switch (s->hdlctx.tx_state) {
298 		default:
299 			clear_bit(0, &s->hdlctx.in_hdlc_tx);
300 			return;
301 		case 0:
302 		case 1:
303 			if (s->hdlctx.numflags) {
304 				s->hdlctx.numflags--;
305 				s->hdlctx.bitbuf |=
306 					0x7e7e << s->hdlctx.numbits;
307 				s->hdlctx.numbits += 16;
308 				break;
309 			}
310 			if (s->hdlctx.tx_state == 1) {
311 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
312 				return;
313 			}
314 			if (!(skb = s->skb)) {
315 				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
316 				if (flgs < 2)
317 					flgs = 2;
318 				s->hdlctx.tx_state = 1;
319 				s->hdlctx.numflags = flgs;
320 				break;
321 			}
322 			s->skb = NULL;
323 			netif_wake_queue(dev);
324 			pkt_len = skb->len-1; /* strip KISS byte */
325 			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
326 				s->hdlctx.tx_state = 0;
327 				s->hdlctx.numflags = 1;
328 				dev_kfree_skb_irq(skb);
329 				break;
330 			}
331 			memcpy(s->hdlctx.buffer, skb->data+1, pkt_len);
332 			dev_kfree_skb_irq(skb);
333 			s->hdlctx.bp = s->hdlctx.buffer;
334 			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
335 			s->hdlctx.len = pkt_len+2; /* the appended CRC */
336 			s->hdlctx.tx_state = 2;
337 			s->hdlctx.bitstream = 0;
338 			s->stats.tx_packets++;
339 			break;
340 		case 2:
341 			if (!s->hdlctx.len) {
342 				s->hdlctx.tx_state = 0;
343 				s->hdlctx.numflags = 1;
344 				break;
345 			}
346 			s->hdlctx.len--;
347 			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
348 				s->hdlctx.numbits;
349 			s->hdlctx.bitstream >>= 8;
350 			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
351 			mask1 = 0x1f000;
352 			mask2 = 0x10000;
353 			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
354 			s->hdlctx.numbits += 8;
355 			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
356 			    mask3 = (mask3 << 1) | 1) {
357 				if ((s->hdlctx.bitstream & mask1) != mask1)
358 					continue;
359 				s->hdlctx.bitstream &= ~mask2;
360 				s->hdlctx.bitbuf =
361 					(s->hdlctx.bitbuf & mask3) |
362 						((s->hdlctx.bitbuf &
363 						 (~mask3)) << 1);
364 				s->hdlctx.numbits++;
365 				mask3 = (mask3 << 1) | 1;
366 			}
367 			break;
368 		}
369 	}
370 }
371 
372 /* ---------------------------------------------------------------------- */
373 
374 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
375 {
376 	s->hdlctx.tx_state = 0;
377 	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
378 	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
379 	hdlcdrv_transmitter(dev, s);
380 	s->hdlctx.ptt = 1;
381 	s->ptt_keyed++;
382 }
383 
384 /* ---------------------------------------------------------------------- */
385 
386 static unsigned short random_seed;
387 
388 static inline unsigned short random_num(void)
389 {
390 	random_seed = 28629 * random_seed + 157;
391 	return random_seed;
392 }
393 
394 /* ---------------------------------------------------------------------- */
395 
396 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
397 {
398 	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
399 		return;
400 	if (s->ch_params.fulldup) {
401 		start_tx(dev, s);
402 		return;
403 	}
404 	if (s->hdlcrx.dcd) {
405 		s->hdlctx.slotcnt = s->ch_params.slottime;
406 		return;
407 	}
408 	if ((--s->hdlctx.slotcnt) > 0)
409 		return;
410 	s->hdlctx.slotcnt = s->ch_params.slottime;
411 	if ((random_num() % 256) > s->ch_params.ppersist)
412 		return;
413 	start_tx(dev, s);
414 }
415 
416 /* --------------------------------------------------------------------- */
417 /*
418  * ===================== network driver interface =========================
419  */
420 
421 static int hdlcdrv_send_packet(struct sk_buff *skb, struct net_device *dev)
422 {
423 	struct hdlcdrv_state *sm = netdev_priv(dev);
424 
425 	if (skb->data[0] != 0) {
426 		do_kiss_params(sm, skb->data, skb->len);
427 		dev_kfree_skb(skb);
428 		return 0;
429 	}
430 	if (sm->skb)
431 		return -1;
432 	netif_stop_queue(dev);
433 	sm->skb = skb;
434 	return 0;
435 }
436 
437 /* --------------------------------------------------------------------- */
438 
439 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
440 {
441 	struct sockaddr *sa = (struct sockaddr *)addr;
442 
443 	/* addr is an AX.25 shifted ASCII mac address */
444 	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
445 	return 0;
446 }
447 
448 /* --------------------------------------------------------------------- */
449 
450 static struct net_device_stats *hdlcdrv_get_stats(struct net_device *dev)
451 {
452 	struct hdlcdrv_state *sm = netdev_priv(dev);
453 
454 	/*
455 	 * Get the current statistics.  This may be called with the
456 	 * card open or closed.
457 	 */
458 	return &sm->stats;
459 }
460 
461 /* --------------------------------------------------------------------- */
462 /*
463  * Open/initialize the board. This is called (in the current kernel)
464  * sometime after booting when the 'ifconfig' program is run.
465  *
466  * This routine should set everything up anew at each open, even
467  * registers that "should" only need to be set once at boot, so that
468  * there is non-reboot way to recover if something goes wrong.
469  */
470 
471 static int hdlcdrv_open(struct net_device *dev)
472 {
473 	struct hdlcdrv_state *s = netdev_priv(dev);
474 	int i;
475 
476 	if (!s->ops || !s->ops->open)
477 		return -ENODEV;
478 
479 	/*
480 	 * initialise some variables
481 	 */
482 	s->opened = 1;
483 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
484 	s->hdlcrx.in_hdlc_rx = 0;
485 	s->hdlcrx.rx_state = 0;
486 
487 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
488 	s->hdlctx.in_hdlc_tx = 0;
489 	s->hdlctx.tx_state = 1;
490 	s->hdlctx.numflags = 0;
491 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
492 	s->hdlctx.ptt = 0;
493 	s->hdlctx.slotcnt = s->ch_params.slottime;
494 	s->hdlctx.calibrate = 0;
495 
496 	i = s->ops->open(dev);
497 	if (i)
498 		return i;
499 	netif_start_queue(dev);
500 	return 0;
501 }
502 
503 /* --------------------------------------------------------------------- */
504 /*
505  * The inverse routine to hdlcdrv_open().
506  */
507 
508 static int hdlcdrv_close(struct net_device *dev)
509 {
510 	struct hdlcdrv_state *s = netdev_priv(dev);
511 	int i = 0;
512 
513 	netif_stop_queue(dev);
514 
515 	if (s->ops && s->ops->close)
516 		i = s->ops->close(dev);
517 	if (s->skb)
518 		dev_kfree_skb(s->skb);
519 	s->skb = NULL;
520 	s->opened = 0;
521 	return i;
522 }
523 
524 /* --------------------------------------------------------------------- */
525 
526 static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
527 {
528 	struct hdlcdrv_state *s = netdev_priv(dev);
529 	struct hdlcdrv_ioctl bi;
530 
531 	if (cmd != SIOCDEVPRIVATE) {
532 		if (s->ops && s->ops->ioctl)
533 			return s->ops->ioctl(dev, ifr, &bi, cmd);
534 		return -ENOIOCTLCMD;
535 	}
536 	if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
537 		return -EFAULT;
538 
539 	switch (bi.cmd) {
540 	default:
541 		if (s->ops && s->ops->ioctl)
542 			return s->ops->ioctl(dev, ifr, &bi, cmd);
543 		return -ENOIOCTLCMD;
544 
545 	case HDLCDRVCTL_GETCHANNELPAR:
546 		bi.data.cp.tx_delay = s->ch_params.tx_delay;
547 		bi.data.cp.tx_tail = s->ch_params.tx_tail;
548 		bi.data.cp.slottime = s->ch_params.slottime;
549 		bi.data.cp.ppersist = s->ch_params.ppersist;
550 		bi.data.cp.fulldup = s->ch_params.fulldup;
551 		break;
552 
553 	case HDLCDRVCTL_SETCHANNELPAR:
554 		if (!capable(CAP_NET_ADMIN))
555 			return -EACCES;
556 		s->ch_params.tx_delay = bi.data.cp.tx_delay;
557 		s->ch_params.tx_tail = bi.data.cp.tx_tail;
558 		s->ch_params.slottime = bi.data.cp.slottime;
559 		s->ch_params.ppersist = bi.data.cp.ppersist;
560 		s->ch_params.fulldup = bi.data.cp.fulldup;
561 		s->hdlctx.slotcnt = 1;
562 		return 0;
563 
564 	case HDLCDRVCTL_GETMODEMPAR:
565 		bi.data.mp.iobase = dev->base_addr;
566 		bi.data.mp.irq = dev->irq;
567 		bi.data.mp.dma = dev->dma;
568 		bi.data.mp.dma2 = s->ptt_out.dma2;
569 		bi.data.mp.seriobase = s->ptt_out.seriobase;
570 		bi.data.mp.pariobase = s->ptt_out.pariobase;
571 		bi.data.mp.midiiobase = s->ptt_out.midiiobase;
572 		break;
573 
574 	case HDLCDRVCTL_SETMODEMPAR:
575 		if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
576 			return -EACCES;
577 		dev->base_addr = bi.data.mp.iobase;
578 		dev->irq = bi.data.mp.irq;
579 		dev->dma = bi.data.mp.dma;
580 		s->ptt_out.dma2 = bi.data.mp.dma2;
581 		s->ptt_out.seriobase = bi.data.mp.seriobase;
582 		s->ptt_out.pariobase = bi.data.mp.pariobase;
583 		s->ptt_out.midiiobase = bi.data.mp.midiiobase;
584 		return 0;
585 
586 	case HDLCDRVCTL_GETSTAT:
587 		bi.data.cs.ptt = hdlcdrv_ptt(s);
588 		bi.data.cs.dcd = s->hdlcrx.dcd;
589 		bi.data.cs.ptt_keyed = s->ptt_keyed;
590 		bi.data.cs.tx_packets = s->stats.tx_packets;
591 		bi.data.cs.tx_errors = s->stats.tx_errors;
592 		bi.data.cs.rx_packets = s->stats.rx_packets;
593 		bi.data.cs.rx_errors = s->stats.rx_errors;
594 		break;
595 
596 	case HDLCDRVCTL_OLDGETSTAT:
597 		bi.data.ocs.ptt = hdlcdrv_ptt(s);
598 		bi.data.ocs.dcd = s->hdlcrx.dcd;
599 		bi.data.ocs.ptt_keyed = s->ptt_keyed;
600 		break;
601 
602 	case HDLCDRVCTL_CALIBRATE:
603 		if(!capable(CAP_SYS_RAWIO))
604 			return -EPERM;
605 		s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
606 		return 0;
607 
608 	case HDLCDRVCTL_GETSAMPLES:
609 #ifndef HDLCDRV_DEBUG
610 		return -EPERM;
611 #else /* HDLCDRV_DEBUG */
612 		if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
613 			return -EAGAIN;
614 		bi.data.bits =
615 			s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
616 		s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
617 			sizeof(s->bitbuf_channel.buffer);
618 		break;
619 #endif /* HDLCDRV_DEBUG */
620 
621 	case HDLCDRVCTL_GETBITS:
622 #ifndef HDLCDRV_DEBUG
623 		return -EPERM;
624 #else /* HDLCDRV_DEBUG */
625 		if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
626 			return -EAGAIN;
627 		bi.data.bits =
628 			s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
629 		s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
630 			sizeof(s->bitbuf_hdlc.buffer);
631 		break;
632 #endif /* HDLCDRV_DEBUG */
633 
634 	case HDLCDRVCTL_DRIVERNAME:
635 		if (s->ops && s->ops->drvname) {
636 			strncpy(bi.data.drivername, s->ops->drvname,
637 				sizeof(bi.data.drivername));
638 			break;
639 		}
640 		bi.data.drivername[0] = '\0';
641 		break;
642 
643 	}
644 	if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
645 		return -EFAULT;
646 	return 0;
647 
648 }
649 
650 /* --------------------------------------------------------------------- */
651 
652 /*
653  * Initialize fields in hdlcdrv
654  */
655 static void hdlcdrv_setup(struct net_device *dev)
656 {
657 	static const struct hdlcdrv_channel_params dflt_ch_params = {
658 		20, 2, 10, 40, 0
659 	};
660 	struct hdlcdrv_state *s = netdev_priv(dev);
661 
662 	/*
663 	 * initialize the hdlcdrv_state struct
664 	 */
665 	s->ch_params = dflt_ch_params;
666 	s->ptt_keyed = 0;
667 
668 	spin_lock_init(&s->hdlcrx.hbuf.lock);
669 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
670 	s->hdlcrx.in_hdlc_rx = 0;
671 	s->hdlcrx.rx_state = 0;
672 
673 	spin_lock_init(&s->hdlctx.hbuf.lock);
674 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
675 	s->hdlctx.in_hdlc_tx = 0;
676 	s->hdlctx.tx_state = 1;
677 	s->hdlctx.numflags = 0;
678 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
679 	s->hdlctx.ptt = 0;
680 	s->hdlctx.slotcnt = s->ch_params.slottime;
681 	s->hdlctx.calibrate = 0;
682 
683 #ifdef HDLCDRV_DEBUG
684 	s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
685 	s->bitbuf_channel.shreg = 0x80;
686 
687 	s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
688 	s->bitbuf_hdlc.shreg = 0x80;
689 #endif /* HDLCDRV_DEBUG */
690 
691 	/*
692 	 * initialize the device struct
693 	 */
694 	dev->open = hdlcdrv_open;
695 	dev->stop = hdlcdrv_close;
696 	dev->do_ioctl = hdlcdrv_ioctl;
697 	dev->hard_start_xmit = hdlcdrv_send_packet;
698 	dev->get_stats = hdlcdrv_get_stats;
699 
700 	/* Fill in the fields of the device structure */
701 
702 	s->skb = NULL;
703 
704 	dev->hard_header = ax25_hard_header;
705 	dev->rebuild_header = ax25_rebuild_header;
706 	dev->set_mac_address = hdlcdrv_set_mac_address;
707 
708 	dev->type = ARPHRD_AX25;           /* AF_AX25 device */
709 	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
710 	dev->mtu = AX25_DEF_PACLEN;        /* eth_mtu is the default */
711 	dev->addr_len = AX25_ADDR_LEN;     /* sizeof an ax.25 address */
712 	memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
713 	memcpy(dev->dev_addr, ax25_nocall, AX25_ADDR_LEN);
714 	dev->tx_queue_len = 16;
715 }
716 
717 /* --------------------------------------------------------------------- */
718 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
719 				    unsigned int privsize, const char *ifname,
720 				    unsigned int baseaddr, unsigned int irq,
721 				    unsigned int dma)
722 {
723 	struct net_device *dev;
724 	struct hdlcdrv_state *s;
725 	int err;
726 
727 	BUG_ON(ops == NULL);
728 
729 	if (privsize < sizeof(struct hdlcdrv_state))
730 		privsize = sizeof(struct hdlcdrv_state);
731 
732 	dev = alloc_netdev(privsize, ifname, hdlcdrv_setup);
733 	if (!dev)
734 		return ERR_PTR(-ENOMEM);
735 
736 	/*
737 	 * initialize part of the hdlcdrv_state struct
738 	 */
739 	s = netdev_priv(dev);
740 	s->magic = HDLCDRV_MAGIC;
741 	s->ops = ops;
742 	dev->base_addr = baseaddr;
743 	dev->irq = irq;
744 	dev->dma = dma;
745 
746 	err = register_netdev(dev);
747 	if (err < 0) {
748 		printk(KERN_WARNING "hdlcdrv: cannot register net "
749 		       "device %s\n", dev->name);
750 		free_netdev(dev);
751 		dev = ERR_PTR(err);
752 	}
753 	return dev;
754 }
755 
756 /* --------------------------------------------------------------------- */
757 
758 void hdlcdrv_unregister(struct net_device *dev)
759 {
760 	struct hdlcdrv_state *s = netdev_priv(dev);
761 
762 	BUG_ON(s->magic != HDLCDRV_MAGIC);
763 
764 	if (s->opened && s->ops->close)
765 		s->ops->close(dev);
766 	unregister_netdev(dev);
767 
768 	free_netdev(dev);
769 }
770 
771 /* --------------------------------------------------------------------- */
772 
773 EXPORT_SYMBOL(hdlcdrv_receiver);
774 EXPORT_SYMBOL(hdlcdrv_transmitter);
775 EXPORT_SYMBOL(hdlcdrv_arbitrate);
776 EXPORT_SYMBOL(hdlcdrv_register);
777 EXPORT_SYMBOL(hdlcdrv_unregister);
778 
779 /* --------------------------------------------------------------------- */
780 
781 static int __init hdlcdrv_init_driver(void)
782 {
783 	printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
784 	printk(KERN_INFO "hdlcdrv: version 0.8 compiled " __TIME__ " " __DATE__ "\n");
785 	return 0;
786 }
787 
788 /* --------------------------------------------------------------------- */
789 
790 static void __exit hdlcdrv_cleanup_driver(void)
791 {
792 	printk(KERN_INFO "hdlcdrv: cleanup\n");
793 }
794 
795 /* --------------------------------------------------------------------- */
796 
797 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
798 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
799 MODULE_LICENSE("GPL");
800 module_init(hdlcdrv_init_driver);
801 module_exit(hdlcdrv_cleanup_driver);
802 
803 /* --------------------------------------------------------------------- */
804