xref: /linux/drivers/net/hamradio/hdlcdrv.c (revision 776cfebb430c7b22c208b1b17add97f354d97cab)
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/config.h>
46 #include <linux/module.h>
47 #include <linux/types.h>
48 #include <linux/net.h>
49 #include <linux/in.h>
50 #include <linux/if.h>
51 #include <linux/slab.h>
52 #include <linux/errno.h>
53 #include <linux/init.h>
54 #include <linux/bitops.h>
55 #include <asm/uaccess.h>
56 
57 #include <linux/netdevice.h>
58 #include <linux/if_arp.h>
59 #include <linux/etherdevice.h>
60 #include <linux/skbuff.h>
61 #include <linux/hdlcdrv.h>
62 /* prototypes for ax25_encapsulate and ax25_rebuild_header */
63 #include <net/ax25.h>
64 
65 /* make genksyms happy */
66 #include <linux/ip.h>
67 #include <linux/udp.h>
68 #include <linux/tcp.h>
69 #include <linux/crc-ccitt.h>
70 
71 /* --------------------------------------------------------------------- */
72 
73 /*
74  * The name of the card. Is used for messages and in the requests for
75  * io regions, irqs and dma channels
76  */
77 
78 static char ax25_bcast[AX25_ADDR_LEN] =
79 {'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '0' << 1};
80 static char ax25_nocall[AX25_ADDR_LEN] =
81 {'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};
82 
83 /* --------------------------------------------------------------------- */
84 
85 #define KISS_VERBOSE
86 
87 /* --------------------------------------------------------------------- */
88 
89 #define PARAM_TXDELAY   1
90 #define PARAM_PERSIST   2
91 #define PARAM_SLOTTIME  3
92 #define PARAM_TXTAIL    4
93 #define PARAM_FULLDUP   5
94 #define PARAM_HARDWARE  6
95 #define PARAM_RETURN    255
96 
97 /* --------------------------------------------------------------------- */
98 /*
99  * the CRC routines are stolen from WAMPES
100  * by Dieter Deyke
101  */
102 
103 
104 /*---------------------------------------------------------------------------*/
105 
106 static inline void append_crc_ccitt(unsigned char *buffer, int len)
107 {
108  	unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
109 	*buffer++ = crc;
110 	*buffer++ = crc >> 8;
111 }
112 
113 /*---------------------------------------------------------------------------*/
114 
115 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
116 {
117 	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
118 }
119 
120 /*---------------------------------------------------------------------------*/
121 
122 #if 0
123 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
124 {
125 	unsigned int crc = 0xffff;
126 
127 	for (; cnt > 0; cnt--)
128 		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
129 	crc ^= 0xffff;
130 	return (crc & 0xffff);
131 }
132 #endif
133 
134 /* ---------------------------------------------------------------------- */
135 
136 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
137 
138 /* ---------------------------------------------------------------------- */
139 /*
140  * The HDLC routines
141  */
142 
143 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
144 			     int num)
145 {
146 	int added = 0;
147 
148 	while (s->hdlcrx.rx_state && num >= 8) {
149 		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
150 			s->hdlcrx.rx_state = 0;
151 			return 0;
152 		}
153 		*s->hdlcrx.bp++ = bits >> (32-num);
154 		s->hdlcrx.len++;
155 		num -= 8;
156 		added += 8;
157 	}
158 	return added;
159 }
160 
161 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
162 {
163 	struct sk_buff *skb;
164 	int pkt_len;
165 	unsigned char *cp;
166 
167 	if (s->hdlcrx.len < 4)
168 		return;
169 	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
170 		return;
171 	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
172 	if (!(skb = dev_alloc_skb(pkt_len))) {
173 		printk("%s: memory squeeze, dropping packet\n", dev->name);
174 		s->stats.rx_dropped++;
175 		return;
176 	}
177 	cp = skb_put(skb, pkt_len);
178 	*cp++ = 0; /* KISS kludge */
179 	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
180 	skb->protocol = ax25_type_trans(skb, dev);
181 	netif_rx(skb);
182 	dev->last_rx = jiffies;
183 	s->stats.rx_packets++;
184 }
185 
186 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
187 {
188 	int i;
189 	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
190 
191 	if (!s || s->magic != HDLCDRV_MAGIC)
192 		return;
193 	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
194 		return;
195 
196 	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
197 		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
198 
199 #ifdef HDLCDRV_DEBUG
200 		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
201 #endif /* HDLCDRV_DEBUG */
202 	       	s->hdlcrx.bitstream >>= 16;
203 		s->hdlcrx.bitstream |= word << 16;
204 		s->hdlcrx.bitbuf >>= 16;
205 		s->hdlcrx.bitbuf |= word << 16;
206 		s->hdlcrx.numbits += 16;
207 		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
208 		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff;
209 		    i >= 0;
210 		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1,
211 		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
212 			if ((s->hdlcrx.bitstream & mask1) == mask1)
213 				s->hdlcrx.rx_state = 0; /* abort received */
214 			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
215 				/* flag received */
216 				if (s->hdlcrx.rx_state) {
217 					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
218 							  << (8+i),
219 							  s->hdlcrx.numbits
220 							  -8-i);
221 					hdlc_rx_flag(dev, s);
222 				}
223 				s->hdlcrx.len = 0;
224 				s->hdlcrx.bp = s->hdlcrx.buffer;
225 				s->hdlcrx.rx_state = 1;
226 				s->hdlcrx.numbits = i;
227 			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
228 				/* stuffed bit */
229 				s->hdlcrx.numbits--;
230 				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
231 					((s->hdlcrx.bitbuf & mask6) << 1);
232 			}
233 		}
234 		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
235 						       s->hdlcrx.numbits);
236 	}
237 	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
238 }
239 
240 /* ---------------------------------------------------------------------- */
241 
242 static inline void do_kiss_params(struct hdlcdrv_state *s,
243 				  unsigned char *data, unsigned long len)
244 {
245 
246 #ifdef KISS_VERBOSE
247 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
248 #else /* KISS_VERBOSE */
249 #define PKP(a,b)
250 #endif /* KISS_VERBOSE */
251 
252 	if (len < 2)
253 		return;
254 	switch(data[0]) {
255 	case PARAM_TXDELAY:
256 		s->ch_params.tx_delay = data[1];
257 		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
258 		break;
259 	case PARAM_PERSIST:
260 		s->ch_params.ppersist = data[1];
261 		PKP("p persistence = %u", s->ch_params.ppersist);
262 		break;
263 	case PARAM_SLOTTIME:
264 		s->ch_params.slottime = data[1];
265 		PKP("slot time = %ums", s->ch_params.slottime);
266 		break;
267 	case PARAM_TXTAIL:
268 		s->ch_params.tx_tail = data[1];
269 		PKP("TX tail = %ums", s->ch_params.tx_tail);
270 		break;
271 	case PARAM_FULLDUP:
272 		s->ch_params.fulldup = !!data[1];
273 		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
274 		break;
275 	default:
276 		break;
277 	}
278 #undef PKP
279 }
280 
281 /* ---------------------------------------------------------------------- */
282 
283 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
284 {
285 	unsigned int mask1, mask2, mask3;
286 	int i;
287 	struct sk_buff *skb;
288 	int pkt_len;
289 
290 	if (!s || s->magic != HDLCDRV_MAGIC)
291 		return;
292 	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
293 		return;
294 	for (;;) {
295 		if (s->hdlctx.numbits >= 16) {
296 			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
297 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
298 				return;
299 			}
300 			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
301 			s->hdlctx.bitbuf >>= 16;
302 			s->hdlctx.numbits -= 16;
303 		}
304 		switch (s->hdlctx.tx_state) {
305 		default:
306 			clear_bit(0, &s->hdlctx.in_hdlc_tx);
307 			return;
308 		case 0:
309 		case 1:
310 			if (s->hdlctx.numflags) {
311 				s->hdlctx.numflags--;
312 				s->hdlctx.bitbuf |=
313 					0x7e7e << s->hdlctx.numbits;
314 				s->hdlctx.numbits += 16;
315 				break;
316 			}
317 			if (s->hdlctx.tx_state == 1) {
318 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
319 				return;
320 			}
321 			if (!(skb = s->skb)) {
322 				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
323 				if (flgs < 2)
324 					flgs = 2;
325 				s->hdlctx.tx_state = 1;
326 				s->hdlctx.numflags = flgs;
327 				break;
328 			}
329 			s->skb = NULL;
330 			netif_wake_queue(dev);
331 			pkt_len = skb->len-1; /* strip KISS byte */
332 			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
333 				s->hdlctx.tx_state = 0;
334 				s->hdlctx.numflags = 1;
335 				dev_kfree_skb_irq(skb);
336 				break;
337 			}
338 			memcpy(s->hdlctx.buffer, skb->data+1, pkt_len);
339 			dev_kfree_skb_irq(skb);
340 			s->hdlctx.bp = s->hdlctx.buffer;
341 			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
342 			s->hdlctx.len = pkt_len+2; /* the appended CRC */
343 			s->hdlctx.tx_state = 2;
344 			s->hdlctx.bitstream = 0;
345 			s->stats.tx_packets++;
346 			break;
347 		case 2:
348 			if (!s->hdlctx.len) {
349 				s->hdlctx.tx_state = 0;
350 				s->hdlctx.numflags = 1;
351 				break;
352 			}
353 			s->hdlctx.len--;
354 			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
355 				s->hdlctx.numbits;
356 			s->hdlctx.bitstream >>= 8;
357 			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
358 			mask1 = 0x1f000;
359 			mask2 = 0x10000;
360 			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
361 			s->hdlctx.numbits += 8;
362 			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
363 			    mask3 = (mask3 << 1) | 1) {
364 				if ((s->hdlctx.bitstream & mask1) != mask1)
365 					continue;
366 				s->hdlctx.bitstream &= ~mask2;
367 				s->hdlctx.bitbuf =
368 					(s->hdlctx.bitbuf & mask3) |
369 						((s->hdlctx.bitbuf &
370 						 (~mask3)) << 1);
371 				s->hdlctx.numbits++;
372 				mask3 = (mask3 << 1) | 1;
373 			}
374 			break;
375 		}
376 	}
377 }
378 
379 /* ---------------------------------------------------------------------- */
380 
381 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
382 {
383 	s->hdlctx.tx_state = 0;
384 	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
385 	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
386 	hdlcdrv_transmitter(dev, s);
387 	s->hdlctx.ptt = 1;
388 	s->ptt_keyed++;
389 }
390 
391 /* ---------------------------------------------------------------------- */
392 
393 static unsigned short random_seed;
394 
395 static inline unsigned short random_num(void)
396 {
397 	random_seed = 28629 * random_seed + 157;
398 	return random_seed;
399 }
400 
401 /* ---------------------------------------------------------------------- */
402 
403 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
404 {
405 	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
406 		return;
407 	if (s->ch_params.fulldup) {
408 		start_tx(dev, s);
409 		return;
410 	}
411 	if (s->hdlcrx.dcd) {
412 		s->hdlctx.slotcnt = s->ch_params.slottime;
413 		return;
414 	}
415 	if ((--s->hdlctx.slotcnt) > 0)
416 		return;
417 	s->hdlctx.slotcnt = s->ch_params.slottime;
418 	if ((random_num() % 256) > s->ch_params.ppersist)
419 		return;
420 	start_tx(dev, s);
421 }
422 
423 /* --------------------------------------------------------------------- */
424 /*
425  * ===================== network driver interface =========================
426  */
427 
428 static int hdlcdrv_send_packet(struct sk_buff *skb, struct net_device *dev)
429 {
430 	struct hdlcdrv_state *sm = netdev_priv(dev);
431 
432 	if (skb->data[0] != 0) {
433 		do_kiss_params(sm, skb->data, skb->len);
434 		dev_kfree_skb(skb);
435 		return 0;
436 	}
437 	if (sm->skb)
438 		return -1;
439 	netif_stop_queue(dev);
440 	sm->skb = skb;
441 	return 0;
442 }
443 
444 /* --------------------------------------------------------------------- */
445 
446 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
447 {
448 	struct sockaddr *sa = (struct sockaddr *)addr;
449 
450 	/* addr is an AX.25 shifted ASCII mac address */
451 	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
452 	return 0;
453 }
454 
455 /* --------------------------------------------------------------------- */
456 
457 static struct net_device_stats *hdlcdrv_get_stats(struct net_device *dev)
458 {
459 	struct hdlcdrv_state *sm = netdev_priv(dev);
460 
461 	/*
462 	 * Get the current statistics.  This may be called with the
463 	 * card open or closed.
464 	 */
465 	return &sm->stats;
466 }
467 
468 /* --------------------------------------------------------------------- */
469 /*
470  * Open/initialize the board. This is called (in the current kernel)
471  * sometime after booting when the 'ifconfig' program is run.
472  *
473  * This routine should set everything up anew at each open, even
474  * registers that "should" only need to be set once at boot, so that
475  * there is non-reboot way to recover if something goes wrong.
476  */
477 
478 static int hdlcdrv_open(struct net_device *dev)
479 {
480 	struct hdlcdrv_state *s = netdev_priv(dev);
481 	int i;
482 
483 	if (!s->ops || !s->ops->open)
484 		return -ENODEV;
485 
486 	/*
487 	 * initialise some variables
488 	 */
489 	s->opened = 1;
490 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
491 	s->hdlcrx.in_hdlc_rx = 0;
492 	s->hdlcrx.rx_state = 0;
493 
494 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
495 	s->hdlctx.in_hdlc_tx = 0;
496 	s->hdlctx.tx_state = 1;
497 	s->hdlctx.numflags = 0;
498 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
499 	s->hdlctx.ptt = 0;
500 	s->hdlctx.slotcnt = s->ch_params.slottime;
501 	s->hdlctx.calibrate = 0;
502 
503 	i = s->ops->open(dev);
504 	if (i)
505 		return i;
506 	netif_start_queue(dev);
507 	return 0;
508 }
509 
510 /* --------------------------------------------------------------------- */
511 /*
512  * The inverse routine to hdlcdrv_open().
513  */
514 
515 static int hdlcdrv_close(struct net_device *dev)
516 {
517 	struct hdlcdrv_state *s = netdev_priv(dev);
518 	int i = 0;
519 
520 	netif_stop_queue(dev);
521 
522 	if (s->ops && s->ops->close)
523 		i = s->ops->close(dev);
524 	if (s->skb)
525 		dev_kfree_skb(s->skb);
526 	s->skb = NULL;
527 	s->opened = 0;
528 	return i;
529 }
530 
531 /* --------------------------------------------------------------------- */
532 
533 static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
534 {
535 	struct hdlcdrv_state *s = netdev_priv(dev);
536 	struct hdlcdrv_ioctl bi;
537 
538 	if (cmd != SIOCDEVPRIVATE) {
539 		if (s->ops && s->ops->ioctl)
540 			return s->ops->ioctl(dev, ifr, &bi, cmd);
541 		return -ENOIOCTLCMD;
542 	}
543 	if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
544 		return -EFAULT;
545 
546 	switch (bi.cmd) {
547 	default:
548 		if (s->ops && s->ops->ioctl)
549 			return s->ops->ioctl(dev, ifr, &bi, cmd);
550 		return -ENOIOCTLCMD;
551 
552 	case HDLCDRVCTL_GETCHANNELPAR:
553 		bi.data.cp.tx_delay = s->ch_params.tx_delay;
554 		bi.data.cp.tx_tail = s->ch_params.tx_tail;
555 		bi.data.cp.slottime = s->ch_params.slottime;
556 		bi.data.cp.ppersist = s->ch_params.ppersist;
557 		bi.data.cp.fulldup = s->ch_params.fulldup;
558 		break;
559 
560 	case HDLCDRVCTL_SETCHANNELPAR:
561 		if (!capable(CAP_NET_ADMIN))
562 			return -EACCES;
563 		s->ch_params.tx_delay = bi.data.cp.tx_delay;
564 		s->ch_params.tx_tail = bi.data.cp.tx_tail;
565 		s->ch_params.slottime = bi.data.cp.slottime;
566 		s->ch_params.ppersist = bi.data.cp.ppersist;
567 		s->ch_params.fulldup = bi.data.cp.fulldup;
568 		s->hdlctx.slotcnt = 1;
569 		return 0;
570 
571 	case HDLCDRVCTL_GETMODEMPAR:
572 		bi.data.mp.iobase = dev->base_addr;
573 		bi.data.mp.irq = dev->irq;
574 		bi.data.mp.dma = dev->dma;
575 		bi.data.mp.dma2 = s->ptt_out.dma2;
576 		bi.data.mp.seriobase = s->ptt_out.seriobase;
577 		bi.data.mp.pariobase = s->ptt_out.pariobase;
578 		bi.data.mp.midiiobase = s->ptt_out.midiiobase;
579 		break;
580 
581 	case HDLCDRVCTL_SETMODEMPAR:
582 		if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
583 			return -EACCES;
584 		dev->base_addr = bi.data.mp.iobase;
585 		dev->irq = bi.data.mp.irq;
586 		dev->dma = bi.data.mp.dma;
587 		s->ptt_out.dma2 = bi.data.mp.dma2;
588 		s->ptt_out.seriobase = bi.data.mp.seriobase;
589 		s->ptt_out.pariobase = bi.data.mp.pariobase;
590 		s->ptt_out.midiiobase = bi.data.mp.midiiobase;
591 		return 0;
592 
593 	case HDLCDRVCTL_GETSTAT:
594 		bi.data.cs.ptt = hdlcdrv_ptt(s);
595 		bi.data.cs.dcd = s->hdlcrx.dcd;
596 		bi.data.cs.ptt_keyed = s->ptt_keyed;
597 		bi.data.cs.tx_packets = s->stats.tx_packets;
598 		bi.data.cs.tx_errors = s->stats.tx_errors;
599 		bi.data.cs.rx_packets = s->stats.rx_packets;
600 		bi.data.cs.rx_errors = s->stats.rx_errors;
601 		break;
602 
603 	case HDLCDRVCTL_OLDGETSTAT:
604 		bi.data.ocs.ptt = hdlcdrv_ptt(s);
605 		bi.data.ocs.dcd = s->hdlcrx.dcd;
606 		bi.data.ocs.ptt_keyed = s->ptt_keyed;
607 		break;
608 
609 	case HDLCDRVCTL_CALIBRATE:
610 		if(!capable(CAP_SYS_RAWIO))
611 			return -EPERM;
612 		s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
613 		return 0;
614 
615 	case HDLCDRVCTL_GETSAMPLES:
616 #ifndef HDLCDRV_DEBUG
617 		return -EPERM;
618 #else /* HDLCDRV_DEBUG */
619 		if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
620 			return -EAGAIN;
621 		bi.data.bits =
622 			s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
623 		s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
624 			sizeof(s->bitbuf_channel.buffer);
625 		break;
626 #endif /* HDLCDRV_DEBUG */
627 
628 	case HDLCDRVCTL_GETBITS:
629 #ifndef HDLCDRV_DEBUG
630 		return -EPERM;
631 #else /* HDLCDRV_DEBUG */
632 		if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
633 			return -EAGAIN;
634 		bi.data.bits =
635 			s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
636 		s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
637 			sizeof(s->bitbuf_hdlc.buffer);
638 		break;
639 #endif /* HDLCDRV_DEBUG */
640 
641 	case HDLCDRVCTL_DRIVERNAME:
642 		if (s->ops && s->ops->drvname) {
643 			strncpy(bi.data.drivername, s->ops->drvname,
644 				sizeof(bi.data.drivername));
645 			break;
646 		}
647 		bi.data.drivername[0] = '\0';
648 		break;
649 
650 	}
651 	if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
652 		return -EFAULT;
653 	return 0;
654 
655 }
656 
657 /* --------------------------------------------------------------------- */
658 
659 /*
660  * Initialize fields in hdlcdrv
661  */
662 static void hdlcdrv_setup(struct net_device *dev)
663 {
664 	static const struct hdlcdrv_channel_params dflt_ch_params = {
665 		20, 2, 10, 40, 0
666 	};
667 	struct hdlcdrv_state *s = netdev_priv(dev);
668 
669 	/*
670 	 * initialize the hdlcdrv_state struct
671 	 */
672 	s->ch_params = dflt_ch_params;
673 	s->ptt_keyed = 0;
674 
675 	spin_lock_init(&s->hdlcrx.hbuf.lock);
676 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
677 	s->hdlcrx.in_hdlc_rx = 0;
678 	s->hdlcrx.rx_state = 0;
679 
680 	spin_lock_init(&s->hdlctx.hbuf.lock);
681 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
682 	s->hdlctx.in_hdlc_tx = 0;
683 	s->hdlctx.tx_state = 1;
684 	s->hdlctx.numflags = 0;
685 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
686 	s->hdlctx.ptt = 0;
687 	s->hdlctx.slotcnt = s->ch_params.slottime;
688 	s->hdlctx.calibrate = 0;
689 
690 #ifdef HDLCDRV_DEBUG
691 	s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
692 	s->bitbuf_channel.shreg = 0x80;
693 
694 	s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
695 	s->bitbuf_hdlc.shreg = 0x80;
696 #endif /* HDLCDRV_DEBUG */
697 
698 	/*
699 	 * initialize the device struct
700 	 */
701 	dev->open = hdlcdrv_open;
702 	dev->stop = hdlcdrv_close;
703 	dev->do_ioctl = hdlcdrv_ioctl;
704 	dev->hard_start_xmit = hdlcdrv_send_packet;
705 	dev->get_stats = hdlcdrv_get_stats;
706 
707 	/* Fill in the fields of the device structure */
708 
709 	s->skb = NULL;
710 
711 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
712 	dev->hard_header = ax25_encapsulate;
713 	dev->rebuild_header = ax25_rebuild_header;
714 #else /* CONFIG_AX25 || CONFIG_AX25_MODULE */
715 	dev->hard_header = NULL;
716 	dev->rebuild_header = NULL;
717 #endif /* CONFIG_AX25 || CONFIG_AX25_MODULE */
718 	dev->set_mac_address = hdlcdrv_set_mac_address;
719 
720 	dev->type = ARPHRD_AX25;           /* AF_AX25 device */
721 	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
722 	dev->mtu = AX25_DEF_PACLEN;        /* eth_mtu is the default */
723 	dev->addr_len = AX25_ADDR_LEN;     /* sizeof an ax.25 address */
724 	memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
725 	memcpy(dev->dev_addr, ax25_nocall, AX25_ADDR_LEN);
726 	dev->tx_queue_len = 16;
727 }
728 
729 /* --------------------------------------------------------------------- */
730 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
731 				    unsigned int privsize, const char *ifname,
732 				    unsigned int baseaddr, unsigned int irq,
733 				    unsigned int dma)
734 {
735 	struct net_device *dev;
736 	struct hdlcdrv_state *s;
737 	int err;
738 
739 	BUG_ON(ops == NULL);
740 
741 	if (privsize < sizeof(struct hdlcdrv_state))
742 		privsize = sizeof(struct hdlcdrv_state);
743 
744 	dev = alloc_netdev(privsize, ifname, hdlcdrv_setup);
745 	if (!dev)
746 		return ERR_PTR(-ENOMEM);
747 
748 	/*
749 	 * initialize part of the hdlcdrv_state struct
750 	 */
751 	s = netdev_priv(dev);
752 	s->magic = HDLCDRV_MAGIC;
753 	s->ops = ops;
754 	dev->base_addr = baseaddr;
755 	dev->irq = irq;
756 	dev->dma = dma;
757 
758 	err = register_netdev(dev);
759 	if (err < 0) {
760 		printk(KERN_WARNING "hdlcdrv: cannot register net "
761 		       "device %s\n", dev->name);
762 		free_netdev(dev);
763 		dev = ERR_PTR(err);
764 	}
765 	return dev;
766 }
767 
768 /* --------------------------------------------------------------------- */
769 
770 void hdlcdrv_unregister(struct net_device *dev)
771 {
772 	struct hdlcdrv_state *s = netdev_priv(dev);
773 
774 	BUG_ON(s->magic != HDLCDRV_MAGIC);
775 
776 	if (s->opened && s->ops->close)
777 		s->ops->close(dev);
778 	unregister_netdev(dev);
779 
780 	free_netdev(dev);
781 }
782 
783 /* --------------------------------------------------------------------- */
784 
785 EXPORT_SYMBOL(hdlcdrv_receiver);
786 EXPORT_SYMBOL(hdlcdrv_transmitter);
787 EXPORT_SYMBOL(hdlcdrv_arbitrate);
788 EXPORT_SYMBOL(hdlcdrv_register);
789 EXPORT_SYMBOL(hdlcdrv_unregister);
790 
791 /* --------------------------------------------------------------------- */
792 
793 static int __init hdlcdrv_init_driver(void)
794 {
795 	printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
796 	printk(KERN_INFO "hdlcdrv: version 0.8 compiled " __TIME__ " " __DATE__ "\n");
797 	return 0;
798 }
799 
800 /* --------------------------------------------------------------------- */
801 
802 static void __exit hdlcdrv_cleanup_driver(void)
803 {
804 	printk(KERN_INFO "hdlcdrv: cleanup\n");
805 }
806 
807 /* --------------------------------------------------------------------- */
808 
809 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
810 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
811 MODULE_LICENSE("GPL");
812 module_init(hdlcdrv_init_driver);
813 module_exit(hdlcdrv_cleanup_driver);
814 
815 /* --------------------------------------------------------------------- */
816