xref: /linux/drivers/net/hamradio/hdlcdrv.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*****************************************************************************/
3 
4 /*
5  *	hdlcdrv.c  -- HDLC packet radio network driver.
6  *
7  *	Copyright (C) 1996-2000  Thomas Sailer (sailer@ife.ee.ethz.ch)
8  *
9  *  Please note that the GPL allows you to use the driver, NOT the radio.
10  *  In order to use the radio, you need a license from the communications
11  *  authority of your country.
12  *
13  *  The driver was derived from Donald Beckers skeleton.c
14  *	Written 1993-94 by Donald Becker.
15  *
16  *  History:
17  *   0.1  21.09.1996  Started
18  *        18.10.1996  Changed to new user space access routines
19  *                    (copy_{to,from}_user)
20  *   0.2  21.11.1996  various small changes
21  *   0.3  03.03.1997  fixed (hopefully) IP not working with ax.25 as a module
22  *   0.4  16.04.1997  init code/data tagged
23  *   0.5  30.07.1997  made HDLC buffers bigger (solves a problem with the
24  *                    soundmodem driver)
25  *   0.6  05.04.1998  add spinlocks
26  *   0.7  03.08.1999  removed some old compatibility cruft
27  *   0.8  12.02.2000  adapted to softnet driver interface
28  */
29 
30 /*****************************************************************************/
31 
32 #include <linux/capability.h>
33 #include <linux/compat.h>
34 #include <linux/module.h>
35 #include <linux/types.h>
36 #include <linux/net.h>
37 #include <linux/in.h>
38 #include <linux/if.h>
39 #include <linux/errno.h>
40 #include <linux/init.h>
41 #include <linux/bitops.h>
42 
43 #include <linux/netdevice.h>
44 #include <linux/if_arp.h>
45 #include <linux/skbuff.h>
46 #include <linux/hdlcdrv.h>
47 #include <linux/random.h>
48 #include <net/ax25.h>
49 #include <linux/uaccess.h>
50 
51 #include <linux/crc-ccitt.h>
52 
53 /* --------------------------------------------------------------------- */
54 
55 #define KISS_VERBOSE
56 
57 /* --------------------------------------------------------------------- */
58 
59 #define PARAM_TXDELAY   1
60 #define PARAM_PERSIST   2
61 #define PARAM_SLOTTIME  3
62 #define PARAM_TXTAIL    4
63 #define PARAM_FULLDUP   5
64 #define PARAM_HARDWARE  6
65 #define PARAM_RETURN    255
66 
67 /* --------------------------------------------------------------------- */
68 /*
69  * the CRC routines are stolen from WAMPES
70  * by Dieter Deyke
71  */
72 
73 
74 /*---------------------------------------------------------------------------*/
75 
append_crc_ccitt(unsigned char * buffer,int len)76 static inline void append_crc_ccitt(unsigned char *buffer, int len)
77 {
78 	unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
79 	buffer += len;
80 	*buffer++ = crc;
81 	*buffer++ = crc >> 8;
82 }
83 
84 /*---------------------------------------------------------------------------*/
85 
check_crc_ccitt(const unsigned char * buf,int cnt)86 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
87 {
88 	return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
89 }
90 
91 /*---------------------------------------------------------------------------*/
92 
93 #if 0
94 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
95 {
96 	unsigned int crc = 0xffff;
97 
98 	for (; cnt > 0; cnt--)
99 		crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
100 	crc ^= 0xffff;
101 	return crc & 0xffff;
102 }
103 #endif
104 
105 /* ---------------------------------------------------------------------- */
106 
107 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
108 
109 /* ---------------------------------------------------------------------- */
110 /*
111  * The HDLC routines
112  */
113 
hdlc_rx_add_bytes(struct hdlcdrv_state * s,unsigned int bits,int num)114 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
115 			     int num)
116 {
117 	int added = 0;
118 
119 	while (s->hdlcrx.rx_state && num >= 8) {
120 		if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
121 			s->hdlcrx.rx_state = 0;
122 			return 0;
123 		}
124 		*s->hdlcrx.bp++ = bits >> (32-num);
125 		s->hdlcrx.len++;
126 		num -= 8;
127 		added += 8;
128 	}
129 	return added;
130 }
131 
hdlc_rx_flag(struct net_device * dev,struct hdlcdrv_state * s)132 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
133 {
134 	struct sk_buff *skb;
135 	int pkt_len;
136 	unsigned char *cp;
137 
138 	if (s->hdlcrx.len < 4)
139 		return;
140 	if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
141 		return;
142 	pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
143 	if (!(skb = dev_alloc_skb(pkt_len))) {
144 		printk("%s: memory squeeze, dropping packet\n", dev->name);
145 		dev->stats.rx_dropped++;
146 		return;
147 	}
148 	cp = skb_put(skb, pkt_len);
149 	*cp++ = 0; /* KISS kludge */
150 	memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
151 	skb->protocol = ax25_type_trans(skb, dev);
152 	netif_rx(skb);
153 	dev->stats.rx_packets++;
154 }
155 
hdlcdrv_receiver(struct net_device * dev,struct hdlcdrv_state * s)156 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
157 {
158 	int i;
159 	unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
160 
161 	if (!s || s->magic != HDLCDRV_MAGIC)
162 		return;
163 	if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
164 		return;
165 
166 	while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
167 		word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
168 
169 #ifdef HDLCDRV_DEBUG
170 		hdlcdrv_add_bitbuffer_word(&s->bitbuf_hdlc, word);
171 #endif /* HDLCDRV_DEBUG */
172 	       	s->hdlcrx.bitstream >>= 16;
173 		s->hdlcrx.bitstream |= word << 16;
174 		s->hdlcrx.bitbuf >>= 16;
175 		s->hdlcrx.bitbuf |= word << 16;
176 		s->hdlcrx.numbits += 16;
177 		for(i = 15, mask1 = 0x1fc00, mask2 = 0x1fe00, mask3 = 0x0fc00,
178 		    mask4 = 0x1f800, mask5 = 0xf800, mask6 = 0xffff;
179 		    i >= 0;
180 		    i--, mask1 <<= 1, mask2 <<= 1, mask3 <<= 1, mask4 <<= 1,
181 		    mask5 <<= 1, mask6 = (mask6 << 1) | 1) {
182 			if ((s->hdlcrx.bitstream & mask1) == mask1)
183 				s->hdlcrx.rx_state = 0; /* abort received */
184 			else if ((s->hdlcrx.bitstream & mask2) == mask3) {
185 				/* flag received */
186 				if (s->hdlcrx.rx_state) {
187 					hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
188 							  << (8+i),
189 							  s->hdlcrx.numbits
190 							  -8-i);
191 					hdlc_rx_flag(dev, s);
192 				}
193 				s->hdlcrx.len = 0;
194 				s->hdlcrx.bp = s->hdlcrx.buffer;
195 				s->hdlcrx.rx_state = 1;
196 				s->hdlcrx.numbits = i;
197 			} else if ((s->hdlcrx.bitstream & mask4) == mask5) {
198 				/* stuffed bit */
199 				s->hdlcrx.numbits--;
200 				s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
201 					((s->hdlcrx.bitbuf & mask6) << 1);
202 			}
203 		}
204 		s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
205 						       s->hdlcrx.numbits);
206 	}
207 	clear_bit(0, &s->hdlcrx.in_hdlc_rx);
208 }
209 
210 /* ---------------------------------------------------------------------- */
211 
do_kiss_params(struct hdlcdrv_state * s,unsigned char * data,unsigned long len)212 static inline void do_kiss_params(struct hdlcdrv_state *s,
213 				  unsigned char *data, unsigned long len)
214 {
215 
216 #ifdef KISS_VERBOSE
217 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
218 #else /* KISS_VERBOSE */
219 #define PKP(a,b)
220 #endif /* KISS_VERBOSE */
221 
222 	if (len < 2)
223 		return;
224 	switch(data[0]) {
225 	case PARAM_TXDELAY:
226 		s->ch_params.tx_delay = data[1];
227 		PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
228 		break;
229 	case PARAM_PERSIST:
230 		s->ch_params.ppersist = data[1];
231 		PKP("p persistence = %u", s->ch_params.ppersist);
232 		break;
233 	case PARAM_SLOTTIME:
234 		s->ch_params.slottime = data[1];
235 		PKP("slot time = %ums", s->ch_params.slottime);
236 		break;
237 	case PARAM_TXTAIL:
238 		s->ch_params.tx_tail = data[1];
239 		PKP("TX tail = %ums", s->ch_params.tx_tail);
240 		break;
241 	case PARAM_FULLDUP:
242 		s->ch_params.fulldup = !!data[1];
243 		PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
244 		break;
245 	default:
246 		break;
247 	}
248 #undef PKP
249 }
250 
251 /* ---------------------------------------------------------------------- */
252 
hdlcdrv_transmitter(struct net_device * dev,struct hdlcdrv_state * s)253 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
254 {
255 	unsigned int mask1, mask2, mask3;
256 	int i;
257 	struct sk_buff *skb;
258 	int pkt_len;
259 
260 	if (!s || s->magic != HDLCDRV_MAGIC)
261 		return;
262 	if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
263 		return;
264 	for (;;) {
265 		if (s->hdlctx.numbits >= 16) {
266 			if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
267 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
268 				return;
269 			}
270 			hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
271 			s->hdlctx.bitbuf >>= 16;
272 			s->hdlctx.numbits -= 16;
273 		}
274 		switch (s->hdlctx.tx_state) {
275 		default:
276 			clear_bit(0, &s->hdlctx.in_hdlc_tx);
277 			return;
278 		case 0:
279 		case 1:
280 			if (s->hdlctx.numflags) {
281 				s->hdlctx.numflags--;
282 				s->hdlctx.bitbuf |=
283 					0x7e7e << s->hdlctx.numbits;
284 				s->hdlctx.numbits += 16;
285 				break;
286 			}
287 			if (s->hdlctx.tx_state == 1) {
288 				clear_bit(0, &s->hdlctx.in_hdlc_tx);
289 				return;
290 			}
291 			if (!(skb = s->skb)) {
292 				int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
293 				if (flgs < 2)
294 					flgs = 2;
295 				s->hdlctx.tx_state = 1;
296 				s->hdlctx.numflags = flgs;
297 				break;
298 			}
299 			s->skb = NULL;
300 			netif_wake_queue(dev);
301 			pkt_len = skb->len-1; /* strip KISS byte */
302 			if (pkt_len >= HDLCDRV_MAXFLEN || pkt_len < 2) {
303 				s->hdlctx.tx_state = 0;
304 				s->hdlctx.numflags = 1;
305 				dev_kfree_skb_irq(skb);
306 				break;
307 			}
308 			skb_copy_from_linear_data_offset(skb, 1,
309 							 s->hdlctx.buffer,
310 							 pkt_len);
311 			dev_kfree_skb_irq(skb);
312 			s->hdlctx.bp = s->hdlctx.buffer;
313 			append_crc_ccitt(s->hdlctx.buffer, pkt_len);
314 			s->hdlctx.len = pkt_len+2; /* the appended CRC */
315 			s->hdlctx.tx_state = 2;
316 			s->hdlctx.bitstream = 0;
317 			dev->stats.tx_packets++;
318 			break;
319 		case 2:
320 			if (!s->hdlctx.len) {
321 				s->hdlctx.tx_state = 0;
322 				s->hdlctx.numflags = 1;
323 				break;
324 			}
325 			s->hdlctx.len--;
326 			s->hdlctx.bitbuf |= *s->hdlctx.bp <<
327 				s->hdlctx.numbits;
328 			s->hdlctx.bitstream >>= 8;
329 			s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
330 			mask1 = 0x1f000;
331 			mask2 = 0x10000;
332 			mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
333 			s->hdlctx.numbits += 8;
334 			for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
335 			    mask3 = (mask3 << 1) | 1) {
336 				if ((s->hdlctx.bitstream & mask1) != mask1)
337 					continue;
338 				s->hdlctx.bitstream &= ~mask2;
339 				s->hdlctx.bitbuf =
340 					(s->hdlctx.bitbuf & mask3) |
341 						((s->hdlctx.bitbuf &
342 						 (~mask3)) << 1);
343 				s->hdlctx.numbits++;
344 				mask3 = (mask3 << 1) | 1;
345 			}
346 			break;
347 		}
348 	}
349 }
350 
351 /* ---------------------------------------------------------------------- */
352 
start_tx(struct net_device * dev,struct hdlcdrv_state * s)353 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
354 {
355 	s->hdlctx.tx_state = 0;
356 	s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
357 	s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
358 	hdlcdrv_transmitter(dev, s);
359 	s->hdlctx.ptt = 1;
360 	s->ptt_keyed++;
361 }
362 
363 /* ---------------------------------------------------------------------- */
364 
hdlcdrv_arbitrate(struct net_device * dev,struct hdlcdrv_state * s)365 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
366 {
367 	if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
368 		return;
369 	if (s->ch_params.fulldup) {
370 		start_tx(dev, s);
371 		return;
372 	}
373 	if (s->hdlcrx.dcd) {
374 		s->hdlctx.slotcnt = s->ch_params.slottime;
375 		return;
376 	}
377 	if ((--s->hdlctx.slotcnt) > 0)
378 		return;
379 	s->hdlctx.slotcnt = s->ch_params.slottime;
380 	if (get_random_u8() > s->ch_params.ppersist)
381 		return;
382 	start_tx(dev, s);
383 }
384 
385 /* --------------------------------------------------------------------- */
386 /*
387  * ===================== network driver interface =========================
388  */
389 
hdlcdrv_send_packet(struct sk_buff * skb,struct net_device * dev)390 static netdev_tx_t hdlcdrv_send_packet(struct sk_buff *skb,
391 				       struct net_device *dev)
392 {
393 	struct hdlcdrv_state *sm = netdev_priv(dev);
394 
395 	if (skb->protocol == htons(ETH_P_IP))
396 		return ax25_ip_xmit(skb);
397 
398 	if (skb->data[0] != 0) {
399 		do_kiss_params(sm, skb->data, skb->len);
400 		dev_kfree_skb(skb);
401 		return NETDEV_TX_OK;
402 	}
403 	if (sm->skb) {
404 		dev_kfree_skb(skb);
405 		return NETDEV_TX_OK;
406 	}
407 	netif_stop_queue(dev);
408 	sm->skb = skb;
409 	return NETDEV_TX_OK;
410 }
411 
412 /* --------------------------------------------------------------------- */
413 
hdlcdrv_set_mac_address(struct net_device * dev,void * addr)414 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
415 {
416 	struct sockaddr *sa = (struct sockaddr *)addr;
417 
418 	/* addr is an AX.25 shifted ASCII mac address */
419 	dev_addr_set(dev, sa->sa_data);
420 	return 0;
421 }
422 
423 /* --------------------------------------------------------------------- */
424 /*
425  * Open/initialize the board. This is called (in the current kernel)
426  * sometime after booting when the 'ifconfig' program is run.
427  *
428  * This routine should set everything up anew at each open, even
429  * registers that "should" only need to be set once at boot, so that
430  * there is non-reboot way to recover if something goes wrong.
431  */
432 
hdlcdrv_open(struct net_device * dev)433 static int hdlcdrv_open(struct net_device *dev)
434 {
435 	struct hdlcdrv_state *s = netdev_priv(dev);
436 	int i;
437 
438 	if (!s->ops || !s->ops->open)
439 		return -ENODEV;
440 
441 	/*
442 	 * initialise some variables
443 	 */
444 	s->opened = 1;
445 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
446 	s->hdlcrx.in_hdlc_rx = 0;
447 	s->hdlcrx.rx_state = 0;
448 
449 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
450 	s->hdlctx.in_hdlc_tx = 0;
451 	s->hdlctx.tx_state = 1;
452 	s->hdlctx.numflags = 0;
453 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
454 	s->hdlctx.ptt = 0;
455 	s->hdlctx.slotcnt = s->ch_params.slottime;
456 	s->hdlctx.calibrate = 0;
457 
458 	i = s->ops->open(dev);
459 	if (i)
460 		return i;
461 	netif_start_queue(dev);
462 	return 0;
463 }
464 
465 /* --------------------------------------------------------------------- */
466 /*
467  * The inverse routine to hdlcdrv_open().
468  */
469 
hdlcdrv_close(struct net_device * dev)470 static int hdlcdrv_close(struct net_device *dev)
471 {
472 	struct hdlcdrv_state *s = netdev_priv(dev);
473 	int i = 0;
474 
475 	netif_stop_queue(dev);
476 
477 	if (s->ops && s->ops->close)
478 		i = s->ops->close(dev);
479 	dev_kfree_skb(s->skb);
480 	s->skb = NULL;
481 	s->opened = 0;
482 	return i;
483 }
484 
485 /* --------------------------------------------------------------------- */
486 
hdlcdrv_siocdevprivate(struct net_device * dev,struct ifreq * ifr,void __user * data,int cmd)487 static int hdlcdrv_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
488 				  void __user *data, int cmd)
489 {
490 	struct hdlcdrv_state *s = netdev_priv(dev);
491 	struct hdlcdrv_ioctl bi;
492 
493 	if (cmd != SIOCDEVPRIVATE)
494 		return -ENOIOCTLCMD;
495 
496 	if (in_compat_syscall()) /* to be implemented */
497 		return -ENOIOCTLCMD;
498 
499 	if (copy_from_user(&bi, data, sizeof(bi)))
500 		return -EFAULT;
501 
502 	switch (bi.cmd) {
503 	default:
504 		if (s->ops && s->ops->ioctl)
505 			return s->ops->ioctl(dev, data, &bi, cmd);
506 		return -ENOIOCTLCMD;
507 
508 	case HDLCDRVCTL_GETCHANNELPAR:
509 		bi.data.cp.tx_delay = s->ch_params.tx_delay;
510 		bi.data.cp.tx_tail = s->ch_params.tx_tail;
511 		bi.data.cp.slottime = s->ch_params.slottime;
512 		bi.data.cp.ppersist = s->ch_params.ppersist;
513 		bi.data.cp.fulldup = s->ch_params.fulldup;
514 		break;
515 
516 	case HDLCDRVCTL_SETCHANNELPAR:
517 		if (!capable(CAP_NET_ADMIN))
518 			return -EACCES;
519 		s->ch_params.tx_delay = bi.data.cp.tx_delay;
520 		s->ch_params.tx_tail = bi.data.cp.tx_tail;
521 		s->ch_params.slottime = bi.data.cp.slottime;
522 		s->ch_params.ppersist = bi.data.cp.ppersist;
523 		s->ch_params.fulldup = bi.data.cp.fulldup;
524 		s->hdlctx.slotcnt = 1;
525 		return 0;
526 
527 	case HDLCDRVCTL_GETMODEMPAR:
528 		bi.data.mp.iobase = dev->base_addr;
529 		bi.data.mp.irq = dev->irq;
530 		bi.data.mp.dma = dev->dma;
531 		bi.data.mp.dma2 = s->ptt_out.dma2;
532 		bi.data.mp.seriobase = s->ptt_out.seriobase;
533 		bi.data.mp.pariobase = s->ptt_out.pariobase;
534 		bi.data.mp.midiiobase = s->ptt_out.midiiobase;
535 		break;
536 
537 	case HDLCDRVCTL_SETMODEMPAR:
538 		if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
539 			return -EACCES;
540 		dev->base_addr = bi.data.mp.iobase;
541 		dev->irq = bi.data.mp.irq;
542 		dev->dma = bi.data.mp.dma;
543 		s->ptt_out.dma2 = bi.data.mp.dma2;
544 		s->ptt_out.seriobase = bi.data.mp.seriobase;
545 		s->ptt_out.pariobase = bi.data.mp.pariobase;
546 		s->ptt_out.midiiobase = bi.data.mp.midiiobase;
547 		return 0;
548 
549 	case HDLCDRVCTL_GETSTAT:
550 		bi.data.cs.ptt = hdlcdrv_ptt(s);
551 		bi.data.cs.dcd = s->hdlcrx.dcd;
552 		bi.data.cs.ptt_keyed = s->ptt_keyed;
553 		bi.data.cs.tx_packets = dev->stats.tx_packets;
554 		bi.data.cs.tx_errors = dev->stats.tx_errors;
555 		bi.data.cs.rx_packets = dev->stats.rx_packets;
556 		bi.data.cs.rx_errors = dev->stats.rx_errors;
557 		break;
558 
559 	case HDLCDRVCTL_OLDGETSTAT:
560 		bi.data.ocs.ptt = hdlcdrv_ptt(s);
561 		bi.data.ocs.dcd = s->hdlcrx.dcd;
562 		bi.data.ocs.ptt_keyed = s->ptt_keyed;
563 		break;
564 
565 	case HDLCDRVCTL_CALIBRATE:
566 		if(!capable(CAP_SYS_RAWIO))
567 			return -EPERM;
568 		if (s->par.bitrate <= 0)
569 			return -EINVAL;
570 		if (bi.data.calibrate > INT_MAX / s->par.bitrate)
571 			return -EINVAL;
572 		s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
573 		return 0;
574 
575 	case HDLCDRVCTL_GETSAMPLES:
576 #ifndef HDLCDRV_DEBUG
577 		return -EPERM;
578 #else /* HDLCDRV_DEBUG */
579 		if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
580 			return -EAGAIN;
581 		bi.data.bits =
582 			s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
583 		s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
584 			sizeof(s->bitbuf_channel.buffer);
585 		break;
586 #endif /* HDLCDRV_DEBUG */
587 
588 	case HDLCDRVCTL_GETBITS:
589 #ifndef HDLCDRV_DEBUG
590 		return -EPERM;
591 #else /* HDLCDRV_DEBUG */
592 		if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
593 			return -EAGAIN;
594 		bi.data.bits =
595 			s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
596 		s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
597 			sizeof(s->bitbuf_hdlc.buffer);
598 		break;
599 #endif /* HDLCDRV_DEBUG */
600 
601 	case HDLCDRVCTL_DRIVERNAME:
602 		if (s->ops && s->ops->drvname) {
603 			strscpy(bi.data.drivername, s->ops->drvname,
604 				sizeof(bi.data.drivername));
605 			break;
606 		}
607 		bi.data.drivername[0] = '\0';
608 		break;
609 
610 	}
611 	if (copy_to_user(data, &bi, sizeof(bi)))
612 		return -EFAULT;
613 	return 0;
614 
615 }
616 
617 /* --------------------------------------------------------------------- */
618 
619 static const struct net_device_ops hdlcdrv_netdev = {
620 	.ndo_open	= hdlcdrv_open,
621 	.ndo_stop	= hdlcdrv_close,
622 	.ndo_start_xmit = hdlcdrv_send_packet,
623 	.ndo_siocdevprivate  = hdlcdrv_siocdevprivate,
624 	.ndo_set_mac_address = hdlcdrv_set_mac_address,
625 };
626 
627 /*
628  * Initialize fields in hdlcdrv
629  */
hdlcdrv_setup(struct net_device * dev)630 static void hdlcdrv_setup(struct net_device *dev)
631 {
632 	static const struct hdlcdrv_channel_params dflt_ch_params = {
633 		20, 2, 10, 40, 0
634 	};
635 	struct hdlcdrv_state *s = netdev_priv(dev);
636 
637 	/*
638 	 * initialize the hdlcdrv_state struct
639 	 */
640 	s->ch_params = dflt_ch_params;
641 	s->ptt_keyed = 0;
642 
643 	spin_lock_init(&s->hdlcrx.hbuf.lock);
644 	s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
645 	s->hdlcrx.in_hdlc_rx = 0;
646 	s->hdlcrx.rx_state = 0;
647 
648 	spin_lock_init(&s->hdlctx.hbuf.lock);
649 	s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
650 	s->hdlctx.in_hdlc_tx = 0;
651 	s->hdlctx.tx_state = 1;
652 	s->hdlctx.numflags = 0;
653 	s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
654 	s->hdlctx.ptt = 0;
655 	s->hdlctx.slotcnt = s->ch_params.slottime;
656 	s->hdlctx.calibrate = 0;
657 
658 #ifdef HDLCDRV_DEBUG
659 	s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
660 	s->bitbuf_channel.shreg = 0x80;
661 
662 	s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
663 	s->bitbuf_hdlc.shreg = 0x80;
664 #endif /* HDLCDRV_DEBUG */
665 
666 
667 	/* Fill in the fields of the device structure */
668 
669 	s->skb = NULL;
670 
671 	dev->netdev_ops = &hdlcdrv_netdev;
672 	dev->header_ops = &ax25_header_ops;
673 
674 	dev->type = ARPHRD_AX25;           /* AF_AX25 device */
675 	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
676 	dev->mtu = AX25_DEF_PACLEN;        /* eth_mtu is the default */
677 	dev->addr_len = AX25_ADDR_LEN;     /* sizeof an ax.25 address */
678 	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
679 	dev_addr_set(dev, (u8 *)&ax25_defaddr);
680 	dev->tx_queue_len = 16;
681 }
682 
683 /* --------------------------------------------------------------------- */
hdlcdrv_register(const struct hdlcdrv_ops * ops,unsigned int privsize,const char * ifname,unsigned int baseaddr,unsigned int irq,unsigned int dma)684 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
685 				    unsigned int privsize, const char *ifname,
686 				    unsigned int baseaddr, unsigned int irq,
687 				    unsigned int dma)
688 {
689 	struct net_device *dev;
690 	struct hdlcdrv_state *s;
691 	int err;
692 
693 	if (privsize < sizeof(struct hdlcdrv_state))
694 		privsize = sizeof(struct hdlcdrv_state);
695 
696 	dev = alloc_netdev(privsize, ifname, NET_NAME_UNKNOWN, hdlcdrv_setup);
697 	if (!dev)
698 		return ERR_PTR(-ENOMEM);
699 
700 	/*
701 	 * initialize part of the hdlcdrv_state struct
702 	 */
703 	s = netdev_priv(dev);
704 	s->magic = HDLCDRV_MAGIC;
705 	s->ops = ops;
706 	dev->base_addr = baseaddr;
707 	dev->irq = irq;
708 	dev->dma = dma;
709 
710 	err = register_netdev(dev);
711 	if (err < 0) {
712 		printk(KERN_WARNING "hdlcdrv: cannot register net "
713 		       "device %s\n", dev->name);
714 		free_netdev(dev);
715 		dev = ERR_PTR(err);
716 	}
717 	return dev;
718 }
719 
720 /* --------------------------------------------------------------------- */
721 
hdlcdrv_unregister(struct net_device * dev)722 void hdlcdrv_unregister(struct net_device *dev)
723 {
724 	struct hdlcdrv_state *s = netdev_priv(dev);
725 
726 	BUG_ON(s->magic != HDLCDRV_MAGIC);
727 
728 	if (s->opened && s->ops->close)
729 		s->ops->close(dev);
730 	unregister_netdev(dev);
731 
732 	free_netdev(dev);
733 }
734 
735 /* --------------------------------------------------------------------- */
736 
737 EXPORT_SYMBOL(hdlcdrv_receiver);
738 EXPORT_SYMBOL(hdlcdrv_transmitter);
739 EXPORT_SYMBOL(hdlcdrv_arbitrate);
740 EXPORT_SYMBOL(hdlcdrv_register);
741 EXPORT_SYMBOL(hdlcdrv_unregister);
742 
743 /* --------------------------------------------------------------------- */
744 
hdlcdrv_init_driver(void)745 static int __init hdlcdrv_init_driver(void)
746 {
747 	printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
748 	printk(KERN_INFO "hdlcdrv: version 0.8\n");
749 	return 0;
750 }
751 
752 /* --------------------------------------------------------------------- */
753 
hdlcdrv_cleanup_driver(void)754 static void __exit hdlcdrv_cleanup_driver(void)
755 {
756 	printk(KERN_INFO "hdlcdrv: cleanup\n");
757 }
758 
759 /* --------------------------------------------------------------------- */
760 
761 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
762 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
763 MODULE_LICENSE("GPL");
764 module_init(hdlcdrv_init_driver);
765 module_exit(hdlcdrv_cleanup_driver);
766 
767 /* --------------------------------------------------------------------- */
768