xref: /openbmc/linux/drivers/net/hamradio/hdlcdrv.c (revision b6dcefde)
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/capability.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 
56 #include <linux/netdevice.h>
57 #include <linux/if_arp.h>
58 #include <linux/skbuff.h>
59 #include <linux/hdlcdrv.h>
60 #include <linux/random.h>
61 #include <net/ax25.h>
62 #include <asm/uaccess.h>
63 
64 #include <linux/crc-ccitt.h>
65 
66 /* --------------------------------------------------------------------- */
67 
68 #define KISS_VERBOSE
69 
70 /* --------------------------------------------------------------------- */
71 
72 #define PARAM_TXDELAY   1
73 #define PARAM_PERSIST   2
74 #define PARAM_SLOTTIME  3
75 #define PARAM_TXTAIL    4
76 #define PARAM_FULLDUP   5
77 #define PARAM_HARDWARE  6
78 #define PARAM_RETURN    255
79 
80 /* --------------------------------------------------------------------- */
81 /*
82  * the CRC routines are stolen from WAMPES
83  * by Dieter Deyke
84  */
85 
86 
87 /*---------------------------------------------------------------------------*/
88 
89 static inline void append_crc_ccitt(unsigned char *buffer, int len)
90 {
91  	unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
92 	buffer += len;
93 	*buffer++ = crc;
94 	*buffer++ = crc >> 8;
95 }
96 
97 /*---------------------------------------------------------------------------*/
98 
99 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
100 {
101 	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
102 }
103 
104 /*---------------------------------------------------------------------------*/
105 
106 #if 0
107 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
108 {
109 	unsigned int crc = 0xffff;
110 
111 	for (; cnt > 0; cnt--)
112 		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
113 	crc ^= 0xffff;
114 	return (crc & 0xffff);
115 }
116 #endif
117 
118 /* ---------------------------------------------------------------------- */
119 
120 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
121 
122 /* ---------------------------------------------------------------------- */
123 /*
124  * The HDLC routines
125  */
126 
127 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
128 			     int num)
129 {
130 	int added = 0;
131 
132 	while (s->hdlcrx.rx_state && num >= 8) {
133 		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
134 			s->hdlcrx.rx_state = 0;
135 			return 0;
136 		}
137 		*s->hdlcrx.bp++ = bits >> (32-num);
138 		s->hdlcrx.len++;
139 		num -= 8;
140 		added += 8;
141 	}
142 	return added;
143 }
144 
145 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
146 {
147 	struct sk_buff *skb;
148 	int pkt_len;
149 	unsigned char *cp;
150 
151 	if (s->hdlcrx.len < 4)
152 		return;
153 	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
154 		return;
155 	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
156 	if (!(skb = dev_alloc_skb(pkt_len))) {
157 		printk("%s: memory squeeze, dropping packet\n", dev->name);
158 		dev->stats.rx_dropped++;
159 		return;
160 	}
161 	cp = skb_put(skb, pkt_len);
162 	*cp++ = 0; /* KISS kludge */
163 	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
164 	skb->protocol = ax25_type_trans(skb, dev);
165 	netif_rx(skb);
166 	dev->stats.rx_packets++;
167 }
168 
169 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
170 {
171 	int i;
172 	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
173 
174 	if (!s || s->magic != HDLCDRV_MAGIC)
175 		return;
176 	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
177 		return;
178 
179 	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
180 		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
181 
182 #ifdef HDLCDRV_DEBUG
183 		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
184 #endif /* HDLCDRV_DEBUG */
185 	       	s->hdlcrx.bitstream >>= 16;
186 		s->hdlcrx.bitstream |= word << 16;
187 		s->hdlcrx.bitbuf >>= 16;
188 		s->hdlcrx.bitbuf |= word << 16;
189 		s->hdlcrx.numbits += 16;
190 		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
191 		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff;
192 		    i >= 0;
193 		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1,
194 		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
195 			if ((s->hdlcrx.bitstream & mask1) == mask1)
196 				s->hdlcrx.rx_state = 0; /* abort received */
197 			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
198 				/* flag received */
199 				if (s->hdlcrx.rx_state) {
200 					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
201 							  << (8+i),
202 							  s->hdlcrx.numbits
203 							  -8-i);
204 					hdlc_rx_flag(dev, s);
205 				}
206 				s->hdlcrx.len = 0;
207 				s->hdlcrx.bp = s->hdlcrx.buffer;
208 				s->hdlcrx.rx_state = 1;
209 				s->hdlcrx.numbits = i;
210 			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
211 				/* stuffed bit */
212 				s->hdlcrx.numbits--;
213 				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
214 					((s->hdlcrx.bitbuf & mask6) << 1);
215 			}
216 		}
217 		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
218 						       s->hdlcrx.numbits);
219 	}
220 	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
221 }
222 
223 /* ---------------------------------------------------------------------- */
224 
225 static inline void do_kiss_params(struct hdlcdrv_state *s,
226 				  unsigned char *data, unsigned long len)
227 {
228 
229 #ifdef KISS_VERBOSE
230 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
231 #else /* KISS_VERBOSE */
232 #define PKP(a,b)
233 #endif /* KISS_VERBOSE */
234 
235 	if (len < 2)
236 		return;
237 	switch(data[0]) {
238 	case PARAM_TXDELAY:
239 		s->ch_params.tx_delay = data[1];
240 		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
241 		break;
242 	case PARAM_PERSIST:
243 		s->ch_params.ppersist = data[1];
244 		PKP("p persistence = %u", s->ch_params.ppersist);
245 		break;
246 	case PARAM_SLOTTIME:
247 		s->ch_params.slottime = data[1];
248 		PKP("slot time = %ums", s->ch_params.slottime);
249 		break;
250 	case PARAM_TXTAIL:
251 		s->ch_params.tx_tail = data[1];
252 		PKP("TX tail = %ums", s->ch_params.tx_tail);
253 		break;
254 	case PARAM_FULLDUP:
255 		s->ch_params.fulldup = !!data[1];
256 		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
257 		break;
258 	default:
259 		break;
260 	}
261 #undef PKP
262 }
263 
264 /* ---------------------------------------------------------------------- */
265 
266 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
267 {
268 	unsigned int mask1, mask2, mask3;
269 	int i;
270 	struct sk_buff *skb;
271 	int pkt_len;
272 
273 	if (!s || s->magic != HDLCDRV_MAGIC)
274 		return;
275 	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
276 		return;
277 	for (;;) {
278 		if (s->hdlctx.numbits >= 16) {
279 			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
280 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
281 				return;
282 			}
283 			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
284 			s->hdlctx.bitbuf >>= 16;
285 			s->hdlctx.numbits -= 16;
286 		}
287 		switch (s->hdlctx.tx_state) {
288 		default:
289 			clear_bit(0, &s->hdlctx.in_hdlc_tx);
290 			return;
291 		case 0:
292 		case 1:
293 			if (s->hdlctx.numflags) {
294 				s->hdlctx.numflags--;
295 				s->hdlctx.bitbuf |=
296 					0x7e7e << s->hdlctx.numbits;
297 				s->hdlctx.numbits += 16;
298 				break;
299 			}
300 			if (s->hdlctx.tx_state == 1) {
301 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
302 				return;
303 			}
304 			if (!(skb = s->skb)) {
305 				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
306 				if (flgs < 2)
307 					flgs = 2;
308 				s->hdlctx.tx_state = 1;
309 				s->hdlctx.numflags = flgs;
310 				break;
311 			}
312 			s->skb = NULL;
313 			netif_wake_queue(dev);
314 			pkt_len = skb->len-1; /* strip KISS byte */
315 			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
316 				s->hdlctx.tx_state = 0;
317 				s->hdlctx.numflags = 1;
318 				dev_kfree_skb_irq(skb);
319 				break;
320 			}
321 			skb_copy_from_linear_data_offset(skb, 1,
322 							 s->hdlctx.buffer,
323 							 pkt_len);
324 			dev_kfree_skb_irq(skb);
325 			s->hdlctx.bp = s->hdlctx.buffer;
326 			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
327 			s->hdlctx.len = pkt_len+2; /* the appended CRC */
328 			s->hdlctx.tx_state = 2;
329 			s->hdlctx.bitstream = 0;
330 			dev->stats.tx_packets++;
331 			break;
332 		case 2:
333 			if (!s->hdlctx.len) {
334 				s->hdlctx.tx_state = 0;
335 				s->hdlctx.numflags = 1;
336 				break;
337 			}
338 			s->hdlctx.len--;
339 			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
340 				s->hdlctx.numbits;
341 			s->hdlctx.bitstream >>= 8;
342 			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
343 			mask1 = 0x1f000;
344 			mask2 = 0x10000;
345 			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
346 			s->hdlctx.numbits += 8;
347 			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
348 			    mask3 = (mask3 << 1) | 1) {
349 				if ((s->hdlctx.bitstream & mask1) != mask1)
350 					continue;
351 				s->hdlctx.bitstream &= ~mask2;
352 				s->hdlctx.bitbuf =
353 					(s->hdlctx.bitbuf & mask3) |
354 						((s->hdlctx.bitbuf &
355 						 (~mask3)) << 1);
356 				s->hdlctx.numbits++;
357 				mask3 = (mask3 << 1) | 1;
358 			}
359 			break;
360 		}
361 	}
362 }
363 
364 /* ---------------------------------------------------------------------- */
365 
366 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
367 {
368 	s->hdlctx.tx_state = 0;
369 	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
370 	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
371 	hdlcdrv_transmitter(dev, s);
372 	s->hdlctx.ptt = 1;
373 	s->ptt_keyed++;
374 }
375 
376 /* ---------------------------------------------------------------------- */
377 
378 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
379 {
380 	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
381 		return;
382 	if (s->ch_params.fulldup) {
383 		start_tx(dev, s);
384 		return;
385 	}
386 	if (s->hdlcrx.dcd) {
387 		s->hdlctx.slotcnt = s->ch_params.slottime;
388 		return;
389 	}
390 	if ((--s->hdlctx.slotcnt) > 0)
391 		return;
392 	s->hdlctx.slotcnt = s->ch_params.slottime;
393 	if ((random32() % 256) > s->ch_params.ppersist)
394 		return;
395 	start_tx(dev, s);
396 }
397 
398 /* --------------------------------------------------------------------- */
399 /*
400  * ===================== network driver interface =========================
401  */
402 
403 static netdev_tx_t hdlcdrv_send_packet(struct sk_buff *skb,
404 				       struct net_device *dev)
405 {
406 	struct hdlcdrv_state *sm = netdev_priv(dev);
407 
408 	if (skb->data[0] != 0) {
409 		do_kiss_params(sm, skb->data, skb->len);
410 		dev_kfree_skb(skb);
411 		return NETDEV_TX_OK;
412 	}
413 	if (sm->skb)
414 		return NETDEV_TX_LOCKED;
415 	netif_stop_queue(dev);
416 	sm->skb = skb;
417 	return NETDEV_TX_OK;
418 }
419 
420 /* --------------------------------------------------------------------- */
421 
422 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
423 {
424 	struct sockaddr *sa = (struct sockaddr *)addr;
425 
426 	/* addr is an AX.25 shifted ASCII mac address */
427 	memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
428 	return 0;
429 }
430 
431 /* --------------------------------------------------------------------- */
432 /*
433  * Open/initialize the board. This is called (in the current kernel)
434  * sometime after booting when the 'ifconfig' program is run.
435  *
436  * This routine should set everything up anew at each open, even
437  * registers that "should" only need to be set once at boot, so that
438  * there is non-reboot way to recover if something goes wrong.
439  */
440 
441 static int hdlcdrv_open(struct net_device *dev)
442 {
443 	struct hdlcdrv_state *s = netdev_priv(dev);
444 	int i;
445 
446 	if (!s->ops || !s->ops->open)
447 		return -ENODEV;
448 
449 	/*
450 	 * initialise some variables
451 	 */
452 	s->opened = 1;
453 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
454 	s->hdlcrx.in_hdlc_rx = 0;
455 	s->hdlcrx.rx_state = 0;
456 
457 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
458 	s->hdlctx.in_hdlc_tx = 0;
459 	s->hdlctx.tx_state = 1;
460 	s->hdlctx.numflags = 0;
461 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
462 	s->hdlctx.ptt = 0;
463 	s->hdlctx.slotcnt = s->ch_params.slottime;
464 	s->hdlctx.calibrate = 0;
465 
466 	i = s->ops->open(dev);
467 	if (i)
468 		return i;
469 	netif_start_queue(dev);
470 	return 0;
471 }
472 
473 /* --------------------------------------------------------------------- */
474 /*
475  * The inverse routine to hdlcdrv_open().
476  */
477 
478 static int hdlcdrv_close(struct net_device *dev)
479 {
480 	struct hdlcdrv_state *s = netdev_priv(dev);
481 	int i = 0;
482 
483 	netif_stop_queue(dev);
484 
485 	if (s->ops && s->ops->close)
486 		i = s->ops->close(dev);
487 	if (s->skb)
488 		dev_kfree_skb(s->skb);
489 	s->skb = NULL;
490 	s->opened = 0;
491 	return i;
492 }
493 
494 /* --------------------------------------------------------------------- */
495 
496 static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
497 {
498 	struct hdlcdrv_state *s = netdev_priv(dev);
499 	struct hdlcdrv_ioctl bi;
500 
501 	if (cmd != SIOCDEVPRIVATE) {
502 		if (s->ops && s->ops->ioctl)
503 			return s->ops->ioctl(dev, ifr, &bi, cmd);
504 		return -ENOIOCTLCMD;
505 	}
506 	if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
507 		return -EFAULT;
508 
509 	switch (bi.cmd) {
510 	default:
511 		if (s->ops && s->ops->ioctl)
512 			return s->ops->ioctl(dev, ifr, &bi, cmd);
513 		return -ENOIOCTLCMD;
514 
515 	case HDLCDRVCTL_GETCHANNELPAR:
516 		bi.data.cp.tx_delay = s->ch_params.tx_delay;
517 		bi.data.cp.tx_tail = s->ch_params.tx_tail;
518 		bi.data.cp.slottime = s->ch_params.slottime;
519 		bi.data.cp.ppersist = s->ch_params.ppersist;
520 		bi.data.cp.fulldup = s->ch_params.fulldup;
521 		break;
522 
523 	case HDLCDRVCTL_SETCHANNELPAR:
524 		if (!capable(CAP_NET_ADMIN))
525 			return -EACCES;
526 		s->ch_params.tx_delay = bi.data.cp.tx_delay;
527 		s->ch_params.tx_tail = bi.data.cp.tx_tail;
528 		s->ch_params.slottime = bi.data.cp.slottime;
529 		s->ch_params.ppersist = bi.data.cp.ppersist;
530 		s->ch_params.fulldup = bi.data.cp.fulldup;
531 		s->hdlctx.slotcnt = 1;
532 		return 0;
533 
534 	case HDLCDRVCTL_GETMODEMPAR:
535 		bi.data.mp.iobase = dev->base_addr;
536 		bi.data.mp.irq = dev->irq;
537 		bi.data.mp.dma = dev->dma;
538 		bi.data.mp.dma2 = s->ptt_out.dma2;
539 		bi.data.mp.seriobase = s->ptt_out.seriobase;
540 		bi.data.mp.pariobase = s->ptt_out.pariobase;
541 		bi.data.mp.midiiobase = s->ptt_out.midiiobase;
542 		break;
543 
544 	case HDLCDRVCTL_SETMODEMPAR:
545 		if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
546 			return -EACCES;
547 		dev->base_addr = bi.data.mp.iobase;
548 		dev->irq = bi.data.mp.irq;
549 		dev->dma = bi.data.mp.dma;
550 		s->ptt_out.dma2 = bi.data.mp.dma2;
551 		s->ptt_out.seriobase = bi.data.mp.seriobase;
552 		s->ptt_out.pariobase = bi.data.mp.pariobase;
553 		s->ptt_out.midiiobase = bi.data.mp.midiiobase;
554 		return 0;
555 
556 	case HDLCDRVCTL_GETSTAT:
557 		bi.data.cs.ptt = hdlcdrv_ptt(s);
558 		bi.data.cs.dcd = s->hdlcrx.dcd;
559 		bi.data.cs.ptt_keyed = s->ptt_keyed;
560 		bi.data.cs.tx_packets = dev->stats.tx_packets;
561 		bi.data.cs.tx_errors = dev->stats.tx_errors;
562 		bi.data.cs.rx_packets = dev->stats.rx_packets;
563 		bi.data.cs.rx_errors = dev->stats.rx_errors;
564 		break;
565 
566 	case HDLCDRVCTL_OLDGETSTAT:
567 		bi.data.ocs.ptt = hdlcdrv_ptt(s);
568 		bi.data.ocs.dcd = s->hdlcrx.dcd;
569 		bi.data.ocs.ptt_keyed = s->ptt_keyed;
570 		break;
571 
572 	case HDLCDRVCTL_CALIBRATE:
573 		if(!capable(CAP_SYS_RAWIO))
574 			return -EPERM;
575 		s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
576 		return 0;
577 
578 	case HDLCDRVCTL_GETSAMPLES:
579 #ifndef HDLCDRV_DEBUG
580 		return -EPERM;
581 #else /* HDLCDRV_DEBUG */
582 		if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
583 			return -EAGAIN;
584 		bi.data.bits =
585 			s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
586 		s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
587 			sizeof(s->bitbuf_channel.buffer);
588 		break;
589 #endif /* HDLCDRV_DEBUG */
590 
591 	case HDLCDRVCTL_GETBITS:
592 #ifndef HDLCDRV_DEBUG
593 		return -EPERM;
594 #else /* HDLCDRV_DEBUG */
595 		if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
596 			return -EAGAIN;
597 		bi.data.bits =
598 			s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
599 		s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
600 			sizeof(s->bitbuf_hdlc.buffer);
601 		break;
602 #endif /* HDLCDRV_DEBUG */
603 
604 	case HDLCDRVCTL_DRIVERNAME:
605 		if (s->ops && s->ops->drvname) {
606 			strncpy(bi.data.drivername, s->ops->drvname,
607 				sizeof(bi.data.drivername));
608 			break;
609 		}
610 		bi.data.drivername[0] = '\0';
611 		break;
612 
613 	}
614 	if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
615 		return -EFAULT;
616 	return 0;
617 
618 }
619 
620 /* --------------------------------------------------------------------- */
621 
622 static const struct net_device_ops hdlcdrv_netdev = {
623 	.ndo_open	= hdlcdrv_open,
624 	.ndo_stop	= hdlcdrv_close,
625 	.ndo_start_xmit = hdlcdrv_send_packet,
626 	.ndo_do_ioctl	= hdlcdrv_ioctl,
627 	.ndo_set_mac_address = hdlcdrv_set_mac_address,
628 };
629 
630 /*
631  * Initialize fields in hdlcdrv
632  */
633 static void hdlcdrv_setup(struct net_device *dev)
634 {
635 	static const struct hdlcdrv_channel_params dflt_ch_params = {
636 		20, 2, 10, 40, 0
637 	};
638 	struct hdlcdrv_state *s = netdev_priv(dev);
639 
640 	/*
641 	 * initialize the hdlcdrv_state struct
642 	 */
643 	s->ch_params = dflt_ch_params;
644 	s->ptt_keyed = 0;
645 
646 	spin_lock_init(&s->hdlcrx.hbuf.lock);
647 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
648 	s->hdlcrx.in_hdlc_rx = 0;
649 	s->hdlcrx.rx_state = 0;
650 
651 	spin_lock_init(&s->hdlctx.hbuf.lock);
652 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
653 	s->hdlctx.in_hdlc_tx = 0;
654 	s->hdlctx.tx_state = 1;
655 	s->hdlctx.numflags = 0;
656 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
657 	s->hdlctx.ptt = 0;
658 	s->hdlctx.slotcnt = s->ch_params.slottime;
659 	s->hdlctx.calibrate = 0;
660 
661 #ifdef HDLCDRV_DEBUG
662 	s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
663 	s->bitbuf_channel.shreg = 0x80;
664 
665 	s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
666 	s->bitbuf_hdlc.shreg = 0x80;
667 #endif /* HDLCDRV_DEBUG */
668 
669 
670 	/* Fill in the fields of the device structure */
671 
672 	s->skb = NULL;
673 
674 	dev->netdev_ops = &hdlcdrv_netdev;
675 	dev->header_ops = &ax25_header_ops;
676 
677 	dev->type = ARPHRD_AX25;           /* AF_AX25 device */
678 	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
679 	dev->mtu = AX25_DEF_PACLEN;        /* eth_mtu is the default */
680 	dev->addr_len = AX25_ADDR_LEN;     /* sizeof an ax.25 address */
681 	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
682 	memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
683 	dev->tx_queue_len = 16;
684 }
685 
686 /* --------------------------------------------------------------------- */
687 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
688 				    unsigned int privsize, const char *ifname,
689 				    unsigned int baseaddr, unsigned int irq,
690 				    unsigned int dma)
691 {
692 	struct net_device *dev;
693 	struct hdlcdrv_state *s;
694 	int err;
695 
696 	BUG_ON(ops == NULL);
697 
698 	if (privsize < sizeof(struct hdlcdrv_state))
699 		privsize = sizeof(struct hdlcdrv_state);
700 
701 	dev = alloc_netdev(privsize, ifname, hdlcdrv_setup);
702 	if (!dev)
703 		return ERR_PTR(-ENOMEM);
704 
705 	/*
706 	 * initialize part of the hdlcdrv_state struct
707 	 */
708 	s = netdev_priv(dev);
709 	s->magic = HDLCDRV_MAGIC;
710 	s->ops = ops;
711 	dev->base_addr = baseaddr;
712 	dev->irq = irq;
713 	dev->dma = dma;
714 
715 	err = register_netdev(dev);
716 	if (err < 0) {
717 		printk(KERN_WARNING "hdlcdrv: cannot register net "
718 		       "device %s\n", dev->name);
719 		free_netdev(dev);
720 		dev = ERR_PTR(err);
721 	}
722 	return dev;
723 }
724 
725 /* --------------------------------------------------------------------- */
726 
727 void hdlcdrv_unregister(struct net_device *dev)
728 {
729 	struct hdlcdrv_state *s = netdev_priv(dev);
730 
731 	BUG_ON(s->magic != HDLCDRV_MAGIC);
732 
733 	if (s->opened && s->ops->close)
734 		s->ops->close(dev);
735 	unregister_netdev(dev);
736 
737 	free_netdev(dev);
738 }
739 
740 /* --------------------------------------------------------------------- */
741 
742 EXPORT_SYMBOL(hdlcdrv_receiver);
743 EXPORT_SYMBOL(hdlcdrv_transmitter);
744 EXPORT_SYMBOL(hdlcdrv_arbitrate);
745 EXPORT_SYMBOL(hdlcdrv_register);
746 EXPORT_SYMBOL(hdlcdrv_unregister);
747 
748 /* --------------------------------------------------------------------- */
749 
750 static int __init hdlcdrv_init_driver(void)
751 {
752 	printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
753 	printk(KERN_INFO "hdlcdrv: version 0.8 compiled " __TIME__ " " __DATE__ "\n");
754 	return 0;
755 }
756 
757 /* --------------------------------------------------------------------- */
758 
759 static void __exit hdlcdrv_cleanup_driver(void)
760 {
761 	printk(KERN_INFO "hdlcdrv: cleanup\n");
762 }
763 
764 /* --------------------------------------------------------------------- */
765 
766 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
767 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
768 MODULE_LICENSE("GPL");
769 module_init(hdlcdrv_init_driver);
770 module_exit(hdlcdrv_cleanup_driver);
771 
772 /* --------------------------------------------------------------------- */
773