xref: /linux/drivers/net/hamradio/hdlcdrv.c (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
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 <linux/random.h>
60 #include <net/ax25.h>
61 #include <asm/uaccess.h>
62 
63 #include <linux/crc-ccitt.h>
64 
65 /* --------------------------------------------------------------------- */
66 
67 #define KISS_VERBOSE
68 
69 /* --------------------------------------------------------------------- */
70 
71 #define PARAM_TXDELAY   1
72 #define PARAM_PERSIST   2
73 #define PARAM_SLOTTIME  3
74 #define PARAM_TXTAIL    4
75 #define PARAM_FULLDUP   5
76 #define PARAM_HARDWARE  6
77 #define PARAM_RETURN    255
78 
79 /* --------------------------------------------------------------------- */
80 /*
81  * the CRC routines are stolen from WAMPES
82  * by Dieter Deyke
83  */
84 
85 
86 /*---------------------------------------------------------------------------*/
87 
88 static inline void append_crc_ccitt(unsigned char *buffer, int len)
89 {
90  	unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
91 	*buffer++ = crc;
92 	*buffer++ = crc >> 8;
93 }
94 
95 /*---------------------------------------------------------------------------*/
96 
97 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
98 {
99 	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
100 }
101 
102 /*---------------------------------------------------------------------------*/
103 
104 #if 0
105 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
106 {
107 	unsigned int crc = 0xffff;
108 
109 	for (; cnt > 0; cnt--)
110 		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
111 	crc ^= 0xffff;
112 	return (crc & 0xffff);
113 }
114 #endif
115 
116 /* ---------------------------------------------------------------------- */
117 
118 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
119 
120 /* ---------------------------------------------------------------------- */
121 /*
122  * The HDLC routines
123  */
124 
125 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
126 			     int num)
127 {
128 	int added = 0;
129 
130 	while (s->hdlcrx.rx_state && num >= 8) {
131 		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
132 			s->hdlcrx.rx_state = 0;
133 			return 0;
134 		}
135 		*s->hdlcrx.bp++ = bits >> (32-num);
136 		s->hdlcrx.len++;
137 		num -= 8;
138 		added += 8;
139 	}
140 	return added;
141 }
142 
143 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
144 {
145 	struct sk_buff *skb;
146 	int pkt_len;
147 	unsigned char *cp;
148 
149 	if (s->hdlcrx.len < 4)
150 		return;
151 	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
152 		return;
153 	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
154 	if (!(skb = dev_alloc_skb(pkt_len))) {
155 		printk("%s: memory squeeze, dropping packet\n", dev->name);
156 		s->stats.rx_dropped++;
157 		return;
158 	}
159 	cp = skb_put(skb, pkt_len);
160 	*cp++ = 0; /* KISS kludge */
161 	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
162 	skb->protocol = ax25_type_trans(skb, dev);
163 	netif_rx(skb);
164 	dev->last_rx = jiffies;
165 	s->stats.rx_packets++;
166 }
167 
168 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
169 {
170 	int i;
171 	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
172 
173 	if (!s || s->magic != HDLCDRV_MAGIC)
174 		return;
175 	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
176 		return;
177 
178 	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
179 		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
180 
181 #ifdef HDLCDRV_DEBUG
182 		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
183 #endif /* HDLCDRV_DEBUG */
184 	       	s->hdlcrx.bitstream >>= 16;
185 		s->hdlcrx.bitstream |= word << 16;
186 		s->hdlcrx.bitbuf >>= 16;
187 		s->hdlcrx.bitbuf |= word << 16;
188 		s->hdlcrx.numbits += 16;
189 		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
190 		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff;
191 		    i >= 0;
192 		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1,
193 		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
194 			if ((s->hdlcrx.bitstream & mask1) == mask1)
195 				s->hdlcrx.rx_state = 0; /* abort received */
196 			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
197 				/* flag received */
198 				if (s->hdlcrx.rx_state) {
199 					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
200 							  << (8+i),
201 							  s->hdlcrx.numbits
202 							  -8-i);
203 					hdlc_rx_flag(dev, s);
204 				}
205 				s->hdlcrx.len = 0;
206 				s->hdlcrx.bp = s->hdlcrx.buffer;
207 				s->hdlcrx.rx_state = 1;
208 				s->hdlcrx.numbits = i;
209 			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
210 				/* stuffed bit */
211 				s->hdlcrx.numbits--;
212 				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
213 					((s->hdlcrx.bitbuf & mask6) << 1);
214 			}
215 		}
216 		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
217 						       s->hdlcrx.numbits);
218 	}
219 	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
220 }
221 
222 /* ---------------------------------------------------------------------- */
223 
224 static inline void do_kiss_params(struct hdlcdrv_state *s,
225 				  unsigned char *data, unsigned long len)
226 {
227 
228 #ifdef KISS_VERBOSE
229 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
230 #else /* KISS_VERBOSE */
231 #define PKP(a,b)
232 #endif /* KISS_VERBOSE */
233 
234 	if (len < 2)
235 		return;
236 	switch(data[0]) {
237 	case PARAM_TXDELAY:
238 		s->ch_params.tx_delay = data[1];
239 		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
240 		break;
241 	case PARAM_PERSIST:
242 		s->ch_params.ppersist = data[1];
243 		PKP("p persistence = %u", s->ch_params.ppersist);
244 		break;
245 	case PARAM_SLOTTIME:
246 		s->ch_params.slottime = data[1];
247 		PKP("slot time = %ums", s->ch_params.slottime);
248 		break;
249 	case PARAM_TXTAIL:
250 		s->ch_params.tx_tail = data[1];
251 		PKP("TX tail = %ums", s->ch_params.tx_tail);
252 		break;
253 	case PARAM_FULLDUP:
254 		s->ch_params.fulldup = !!data[1];
255 		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
256 		break;
257 	default:
258 		break;
259 	}
260 #undef PKP
261 }
262 
263 /* ---------------------------------------------------------------------- */
264 
265 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
266 {
267 	unsigned int mask1, mask2, mask3;
268 	int i;
269 	struct sk_buff *skb;
270 	int pkt_len;
271 
272 	if (!s || s->magic != HDLCDRV_MAGIC)
273 		return;
274 	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
275 		return;
276 	for (;;) {
277 		if (s->hdlctx.numbits >= 16) {
278 			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
279 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
280 				return;
281 			}
282 			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
283 			s->hdlctx.bitbuf >>= 16;
284 			s->hdlctx.numbits -= 16;
285 		}
286 		switch (s->hdlctx.tx_state) {
287 		default:
288 			clear_bit(0, &s->hdlctx.in_hdlc_tx);
289 			return;
290 		case 0:
291 		case 1:
292 			if (s->hdlctx.numflags) {
293 				s->hdlctx.numflags--;
294 				s->hdlctx.bitbuf |=
295 					0x7e7e << s->hdlctx.numbits;
296 				s->hdlctx.numbits += 16;
297 				break;
298 			}
299 			if (s->hdlctx.tx_state == 1) {
300 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
301 				return;
302 			}
303 			if (!(skb = s->skb)) {
304 				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
305 				if (flgs < 2)
306 					flgs = 2;
307 				s->hdlctx.tx_state = 1;
308 				s->hdlctx.numflags = flgs;
309 				break;
310 			}
311 			s->skb = NULL;
312 			netif_wake_queue(dev);
313 			pkt_len = skb->len-1; /* strip KISS byte */
314 			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
315 				s->hdlctx.tx_state = 0;
316 				s->hdlctx.numflags = 1;
317 				dev_kfree_skb_irq(skb);
318 				break;
319 			}
320 			memcpy(s->hdlctx.buffer, skb->data+1, pkt_len);
321 			dev_kfree_skb_irq(skb);
322 			s->hdlctx.bp = s->hdlctx.buffer;
323 			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
324 			s->hdlctx.len = pkt_len+2; /* the appended CRC */
325 			s->hdlctx.tx_state = 2;
326 			s->hdlctx.bitstream = 0;
327 			s->stats.tx_packets++;
328 			break;
329 		case 2:
330 			if (!s->hdlctx.len) {
331 				s->hdlctx.tx_state = 0;
332 				s->hdlctx.numflags = 1;
333 				break;
334 			}
335 			s->hdlctx.len--;
336 			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
337 				s->hdlctx.numbits;
338 			s->hdlctx.bitstream >>= 8;
339 			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
340 			mask1 = 0x1f000;
341 			mask2 = 0x10000;
342 			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
343 			s->hdlctx.numbits += 8;
344 			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
345 			    mask3 = (mask3 << 1) | 1) {
346 				if ((s->hdlctx.bitstream & mask1) != mask1)
347 					continue;
348 				s->hdlctx.bitstream &= ~mask2;
349 				s->hdlctx.bitbuf =
350 					(s->hdlctx.bitbuf & mask3) |
351 						((s->hdlctx.bitbuf &
352 						 (~mask3)) << 1);
353 				s->hdlctx.numbits++;
354 				mask3 = (mask3 << 1) | 1;
355 			}
356 			break;
357 		}
358 	}
359 }
360 
361 /* ---------------------------------------------------------------------- */
362 
363 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
364 {
365 	s->hdlctx.tx_state = 0;
366 	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
367 	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
368 	hdlcdrv_transmitter(dev, s);
369 	s->hdlctx.ptt = 1;
370 	s->ptt_keyed++;
371 }
372 
373 /* ---------------------------------------------------------------------- */
374 
375 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
376 {
377 	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
378 		return;
379 	if (s->ch_params.fulldup) {
380 		start_tx(dev, s);
381 		return;
382 	}
383 	if (s->hdlcrx.dcd) {
384 		s->hdlctx.slotcnt = s->ch_params.slottime;
385 		return;
386 	}
387 	if ((--s->hdlctx.slotcnt) > 0)
388 		return;
389 	s->hdlctx.slotcnt = s->ch_params.slottime;
390 	if ((random32() % 256) > s->ch_params.ppersist)
391 		return;
392 	start_tx(dev, s);
393 }
394 
395 /* --------------------------------------------------------------------- */
396 /*
397  * ===================== network driver interface =========================
398  */
399 
400 static int hdlcdrv_send_packet(struct sk_buff *skb, struct net_device *dev)
401 {
402 	struct hdlcdrv_state *sm = netdev_priv(dev);
403 
404 	if (skb->data[0] != 0) {
405 		do_kiss_params(sm, skb->data, skb->len);
406 		dev_kfree_skb(skb);
407 		return 0;
408 	}
409 	if (sm->skb)
410 		return -1;
411 	netif_stop_queue(dev);
412 	sm->skb = skb;
413 	return 0;
414 }
415 
416 /* --------------------------------------------------------------------- */
417 
418 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
419 {
420 	struct sockaddr *sa = (struct sockaddr *)addr;
421 
422 	/* addr is an AX.25 shifted ASCII mac address */
423 	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
424 	return 0;
425 }
426 
427 /* --------------------------------------------------------------------- */
428 
429 static struct net_device_stats *hdlcdrv_get_stats(struct net_device *dev)
430 {
431 	struct hdlcdrv_state *sm = netdev_priv(dev);
432 
433 	/*
434 	 * Get the current statistics.  This may be called with the
435 	 * card open or closed.
436 	 */
437 	return &sm->stats;
438 }
439 
440 /* --------------------------------------------------------------------- */
441 /*
442  * Open/initialize the board. This is called (in the current kernel)
443  * sometime after booting when the 'ifconfig' program is run.
444  *
445  * This routine should set everything up anew at each open, even
446  * registers that "should" only need to be set once at boot, so that
447  * there is non-reboot way to recover if something goes wrong.
448  */
449 
450 static int hdlcdrv_open(struct net_device *dev)
451 {
452 	struct hdlcdrv_state *s = netdev_priv(dev);
453 	int i;
454 
455 	if (!s->ops || !s->ops->open)
456 		return -ENODEV;
457 
458 	/*
459 	 * initialise some variables
460 	 */
461 	s->opened = 1;
462 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
463 	s->hdlcrx.in_hdlc_rx = 0;
464 	s->hdlcrx.rx_state = 0;
465 
466 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
467 	s->hdlctx.in_hdlc_tx = 0;
468 	s->hdlctx.tx_state = 1;
469 	s->hdlctx.numflags = 0;
470 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
471 	s->hdlctx.ptt = 0;
472 	s->hdlctx.slotcnt = s->ch_params.slottime;
473 	s->hdlctx.calibrate = 0;
474 
475 	i = s->ops->open(dev);
476 	if (i)
477 		return i;
478 	netif_start_queue(dev);
479 	return 0;
480 }
481 
482 /* --------------------------------------------------------------------- */
483 /*
484  * The inverse routine to hdlcdrv_open().
485  */
486 
487 static int hdlcdrv_close(struct net_device *dev)
488 {
489 	struct hdlcdrv_state *s = netdev_priv(dev);
490 	int i = 0;
491 
492 	netif_stop_queue(dev);
493 
494 	if (s->ops && s->ops->close)
495 		i = s->ops->close(dev);
496 	if (s->skb)
497 		dev_kfree_skb(s->skb);
498 	s->skb = NULL;
499 	s->opened = 0;
500 	return i;
501 }
502 
503 /* --------------------------------------------------------------------- */
504 
505 static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
506 {
507 	struct hdlcdrv_state *s = netdev_priv(dev);
508 	struct hdlcdrv_ioctl bi;
509 
510 	if (cmd != SIOCDEVPRIVATE) {
511 		if (s->ops && s->ops->ioctl)
512 			return s->ops->ioctl(dev, ifr, &bi, cmd);
513 		return -ENOIOCTLCMD;
514 	}
515 	if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
516 		return -EFAULT;
517 
518 	switch (bi.cmd) {
519 	default:
520 		if (s->ops && s->ops->ioctl)
521 			return s->ops->ioctl(dev, ifr, &bi, cmd);
522 		return -ENOIOCTLCMD;
523 
524 	case HDLCDRVCTL_GETCHANNELPAR:
525 		bi.data.cp.tx_delay = s->ch_params.tx_delay;
526 		bi.data.cp.tx_tail = s->ch_params.tx_tail;
527 		bi.data.cp.slottime = s->ch_params.slottime;
528 		bi.data.cp.ppersist = s->ch_params.ppersist;
529 		bi.data.cp.fulldup = s->ch_params.fulldup;
530 		break;
531 
532 	case HDLCDRVCTL_SETCHANNELPAR:
533 		if (!capable(CAP_NET_ADMIN))
534 			return -EACCES;
535 		s->ch_params.tx_delay = bi.data.cp.tx_delay;
536 		s->ch_params.tx_tail = bi.data.cp.tx_tail;
537 		s->ch_params.slottime = bi.data.cp.slottime;
538 		s->ch_params.ppersist = bi.data.cp.ppersist;
539 		s->ch_params.fulldup = bi.data.cp.fulldup;
540 		s->hdlctx.slotcnt = 1;
541 		return 0;
542 
543 	case HDLCDRVCTL_GETMODEMPAR:
544 		bi.data.mp.iobase = dev->base_addr;
545 		bi.data.mp.irq = dev->irq;
546 		bi.data.mp.dma = dev->dma;
547 		bi.data.mp.dma2 = s->ptt_out.dma2;
548 		bi.data.mp.seriobase = s->ptt_out.seriobase;
549 		bi.data.mp.pariobase = s->ptt_out.pariobase;
550 		bi.data.mp.midiiobase = s->ptt_out.midiiobase;
551 		break;
552 
553 	case HDLCDRVCTL_SETMODEMPAR:
554 		if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
555 			return -EACCES;
556 		dev->base_addr = bi.data.mp.iobase;
557 		dev->irq = bi.data.mp.irq;
558 		dev->dma = bi.data.mp.dma;
559 		s->ptt_out.dma2 = bi.data.mp.dma2;
560 		s->ptt_out.seriobase = bi.data.mp.seriobase;
561 		s->ptt_out.pariobase = bi.data.mp.pariobase;
562 		s->ptt_out.midiiobase = bi.data.mp.midiiobase;
563 		return 0;
564 
565 	case HDLCDRVCTL_GETSTAT:
566 		bi.data.cs.ptt = hdlcdrv_ptt(s);
567 		bi.data.cs.dcd = s->hdlcrx.dcd;
568 		bi.data.cs.ptt_keyed = s->ptt_keyed;
569 		bi.data.cs.tx_packets = s->stats.tx_packets;
570 		bi.data.cs.tx_errors = s->stats.tx_errors;
571 		bi.data.cs.rx_packets = s->stats.rx_packets;
572 		bi.data.cs.rx_errors = s->stats.rx_errors;
573 		break;
574 
575 	case HDLCDRVCTL_OLDGETSTAT:
576 		bi.data.ocs.ptt = hdlcdrv_ptt(s);
577 		bi.data.ocs.dcd = s->hdlcrx.dcd;
578 		bi.data.ocs.ptt_keyed = s->ptt_keyed;
579 		break;
580 
581 	case HDLCDRVCTL_CALIBRATE:
582 		if(!capable(CAP_SYS_RAWIO))
583 			return -EPERM;
584 		s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
585 		return 0;
586 
587 	case HDLCDRVCTL_GETSAMPLES:
588 #ifndef HDLCDRV_DEBUG
589 		return -EPERM;
590 #else /* HDLCDRV_DEBUG */
591 		if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
592 			return -EAGAIN;
593 		bi.data.bits =
594 			s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
595 		s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
596 			sizeof(s->bitbuf_channel.buffer);
597 		break;
598 #endif /* HDLCDRV_DEBUG */
599 
600 	case HDLCDRVCTL_GETBITS:
601 #ifndef HDLCDRV_DEBUG
602 		return -EPERM;
603 #else /* HDLCDRV_DEBUG */
604 		if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
605 			return -EAGAIN;
606 		bi.data.bits =
607 			s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
608 		s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
609 			sizeof(s->bitbuf_hdlc.buffer);
610 		break;
611 #endif /* HDLCDRV_DEBUG */
612 
613 	case HDLCDRVCTL_DRIVERNAME:
614 		if (s->ops && s->ops->drvname) {
615 			strncpy(bi.data.drivername, s->ops->drvname,
616 				sizeof(bi.data.drivername));
617 			break;
618 		}
619 		bi.data.drivername[0] = '\0';
620 		break;
621 
622 	}
623 	if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
624 		return -EFAULT;
625 	return 0;
626 
627 }
628 
629 /* --------------------------------------------------------------------- */
630 
631 /*
632  * Initialize fields in hdlcdrv
633  */
634 static void hdlcdrv_setup(struct net_device *dev)
635 {
636 	static const struct hdlcdrv_channel_params dflt_ch_params = {
637 		20, 2, 10, 40, 0
638 	};
639 	struct hdlcdrv_state *s = netdev_priv(dev);
640 
641 	/*
642 	 * initialize the hdlcdrv_state struct
643 	 */
644 	s->ch_params = dflt_ch_params;
645 	s->ptt_keyed = 0;
646 
647 	spin_lock_init(&s->hdlcrx.hbuf.lock);
648 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
649 	s->hdlcrx.in_hdlc_rx = 0;
650 	s->hdlcrx.rx_state = 0;
651 
652 	spin_lock_init(&s->hdlctx.hbuf.lock);
653 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
654 	s->hdlctx.in_hdlc_tx = 0;
655 	s->hdlctx.tx_state = 1;
656 	s->hdlctx.numflags = 0;
657 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
658 	s->hdlctx.ptt = 0;
659 	s->hdlctx.slotcnt = s->ch_params.slottime;
660 	s->hdlctx.calibrate = 0;
661 
662 #ifdef HDLCDRV_DEBUG
663 	s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
664 	s->bitbuf_channel.shreg = 0x80;
665 
666 	s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
667 	s->bitbuf_hdlc.shreg = 0x80;
668 #endif /* HDLCDRV_DEBUG */
669 
670 	/*
671 	 * initialize the device struct
672 	 */
673 	dev->open = hdlcdrv_open;
674 	dev->stop = hdlcdrv_close;
675 	dev->do_ioctl = hdlcdrv_ioctl;
676 	dev->hard_start_xmit = hdlcdrv_send_packet;
677 	dev->get_stats = hdlcdrv_get_stats;
678 
679 	/* Fill in the fields of the device structure */
680 
681 	s->skb = NULL;
682 
683 	dev->hard_header = ax25_hard_header;
684 	dev->rebuild_header = ax25_rebuild_header;
685 	dev->set_mac_address = hdlcdrv_set_mac_address;
686 
687 	dev->type = ARPHRD_AX25;           /* AF_AX25 device */
688 	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
689 	dev->mtu = AX25_DEF_PACLEN;        /* eth_mtu is the default */
690 	dev->addr_len = AX25_ADDR_LEN;     /* sizeof an ax.25 address */
691 	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
692 	memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
693 	dev->tx_queue_len = 16;
694 }
695 
696 /* --------------------------------------------------------------------- */
697 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
698 				    unsigned int privsize, const char *ifname,
699 				    unsigned int baseaddr, unsigned int irq,
700 				    unsigned int dma)
701 {
702 	struct net_device *dev;
703 	struct hdlcdrv_state *s;
704 	int err;
705 
706 	BUG_ON(ops == NULL);
707 
708 	if (privsize < sizeof(struct hdlcdrv_state))
709 		privsize = sizeof(struct hdlcdrv_state);
710 
711 	dev = alloc_netdev(privsize, ifname, hdlcdrv_setup);
712 	if (!dev)
713 		return ERR_PTR(-ENOMEM);
714 
715 	/*
716 	 * initialize part of the hdlcdrv_state struct
717 	 */
718 	s = netdev_priv(dev);
719 	s->magic = HDLCDRV_MAGIC;
720 	s->ops = ops;
721 	dev->base_addr = baseaddr;
722 	dev->irq = irq;
723 	dev->dma = dma;
724 
725 	err = register_netdev(dev);
726 	if (err < 0) {
727 		printk(KERN_WARNING "hdlcdrv: cannot register net "
728 		       "device %s\n", dev->name);
729 		free_netdev(dev);
730 		dev = ERR_PTR(err);
731 	}
732 	return dev;
733 }
734 
735 /* --------------------------------------------------------------------- */
736 
737 void hdlcdrv_unregister(struct net_device *dev)
738 {
739 	struct hdlcdrv_state *s = netdev_priv(dev);
740 
741 	BUG_ON(s->magic != HDLCDRV_MAGIC);
742 
743 	if (s->opened && s->ops->close)
744 		s->ops->close(dev);
745 	unregister_netdev(dev);
746 
747 	free_netdev(dev);
748 }
749 
750 /* --------------------------------------------------------------------- */
751 
752 EXPORT_SYMBOL(hdlcdrv_receiver);
753 EXPORT_SYMBOL(hdlcdrv_transmitter);
754 EXPORT_SYMBOL(hdlcdrv_arbitrate);
755 EXPORT_SYMBOL(hdlcdrv_register);
756 EXPORT_SYMBOL(hdlcdrv_unregister);
757 
758 /* --------------------------------------------------------------------- */
759 
760 static int __init hdlcdrv_init_driver(void)
761 {
762 	printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
763 	printk(KERN_INFO "hdlcdrv: version 0.8 compiled " __TIME__ " " __DATE__ "\n");
764 	return 0;
765 }
766 
767 /* --------------------------------------------------------------------- */
768 
769 static void __exit hdlcdrv_cleanup_driver(void)
770 {
771 	printk(KERN_INFO "hdlcdrv: cleanup\n");
772 }
773 
774 /* --------------------------------------------------------------------- */
775 
776 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
777 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
778 MODULE_LICENSE("GPL");
779 module_init(hdlcdrv_init_driver);
780 module_exit(hdlcdrv_cleanup_driver);
781 
782 /* --------------------------------------------------------------------- */
783