1 /*****************************************************************************/
4 * hdlcdrv.c -- HDLC packet radio network driver.
6 * Copyright (C) 1996-2000 Thomas Sailer (sailer@ife.ee.ethz.ch)
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.
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.
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.
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.
26 * The driver was derived from Donald Beckers skeleton.c
27 * Written 1993-94 by Donald Becker.
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
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
43 /*****************************************************************************/
45 #include <linux/module.h>
46 #include <linux/types.h>
47 #include <linux/net.h>
50 #include <linux/slab.h>
51 #include <linux/errno.h>
52 #include <linux/init.h>
53 #include <linux/bitops.h>
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>
61 #include <asm/uaccess.h>
63 #include <linux/crc-ccitt.h>
65 /* --------------------------------------------------------------------- */
69 /* --------------------------------------------------------------------- */
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
79 /* --------------------------------------------------------------------- */
81 * the CRC routines are stolen from WAMPES
86 /*---------------------------------------------------------------------------*/
88 static inline void append_crc_ccitt(unsigned char *buffer, int len)
90 unsigned int crc = crc_ccitt(0xffff, buffer, len) ^ 0xffff;
96 /*---------------------------------------------------------------------------*/
98 static inline int check_crc_ccitt(const unsigned char *buf, int cnt)
100 return (crc_ccitt(0xffff, buf, cnt) & 0xffff) == 0xf0b8;
103 /*---------------------------------------------------------------------------*/
106 static int calc_crc_ccitt(const unsigned char *buf, int cnt)
108 unsigned int crc = 0xffff;
110 for (; cnt > 0; cnt--)
111 crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ *buf++) & 0xff];
113 return (crc & 0xffff);
117 /* ---------------------------------------------------------------------- */
119 #define tenms_to_2flags(s,tenms) ((tenms * s->par.bitrate) / 100 / 16)
121 /* ---------------------------------------------------------------------- */
126 static int hdlc_rx_add_bytes(struct hdlcdrv_state *s, unsigned int bits,
131 while (s->hdlcrx.rx_state && num >= 8) {
132 if (s->hdlcrx.len >= sizeof(s->hdlcrx.buffer)) {
133 s->hdlcrx.rx_state = 0;
136 *s->hdlcrx.bp++ = bits >> (32-num);
144 static void hdlc_rx_flag(struct net_device *dev, struct hdlcdrv_state *s)
150 if (s->hdlcrx.len < 4)
152 if (!check_crc_ccitt(s->hdlcrx.buffer, s->hdlcrx.len))
154 pkt_len = s->hdlcrx.len - 2 + 1; /* KISS kludge */
155 if (!(skb = dev_alloc_skb(pkt_len))) {
156 printk("%s: memory squeeze, dropping packet\n", dev->name);
157 s->stats.rx_dropped++;
160 cp = skb_put(skb, pkt_len);
161 *cp++ = 0; /* KISS kludge */
162 memcpy(cp, s->hdlcrx.buffer, pkt_len - 1);
163 skb->protocol = ax25_type_trans(skb, dev);
165 s->stats.rx_packets++;
168 void hdlcdrv_receiver(struct net_device *dev, struct hdlcdrv_state *s)
171 unsigned int mask1, mask2, mask3, mask4, mask5, mask6, word;
173 if (!s || s->magic != HDLCDRV_MAGIC)
175 if (test_and_set_bit(0, &s->hdlcrx.in_hdlc_rx))
178 while (!hdlcdrv_hbuf_empty(&s->hdlcrx.hbuf)) {
179 word = hdlcdrv_hbuf_get(&s->hdlcrx.hbuf);
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;
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) {
198 if (s->hdlcrx.rx_state) {
199 hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf
203 hdlc_rx_flag(dev, s);
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) {
212 s->hdlcrx.bitbuf = (s->hdlcrx.bitbuf & (~mask6)) |
213 ((s->hdlcrx.bitbuf & mask6) << 1);
216 s->hdlcrx.numbits -= hdlc_rx_add_bytes(s, s->hdlcrx.bitbuf,
219 clear_bit(0, &s->hdlcrx.in_hdlc_rx);
222 /* ---------------------------------------------------------------------- */
224 static inline void do_kiss_params(struct hdlcdrv_state *s,
225 unsigned char *data, unsigned long len)
229 #define PKP(a,b) printk(KERN_INFO "hdlcdrv.c: channel params: " a "\n", b)
230 #else /* KISS_VERBOSE */
232 #endif /* KISS_VERBOSE */
238 s->ch_params.tx_delay = data[1];
239 PKP("TX delay = %ums", 10 * s->ch_params.tx_delay);
242 s->ch_params.ppersist = data[1];
243 PKP("p persistence = %u", s->ch_params.ppersist);
246 s->ch_params.slottime = data[1];
247 PKP("slot time = %ums", s->ch_params.slottime);
250 s->ch_params.tx_tail = data[1];
251 PKP("TX tail = %ums", s->ch_params.tx_tail);
254 s->ch_params.fulldup = !!data[1];
255 PKP("%s duplex", s->ch_params.fulldup ? "full" : "half");
263 /* ---------------------------------------------------------------------- */
265 void hdlcdrv_transmitter(struct net_device *dev, struct hdlcdrv_state *s)
267 unsigned int mask1, mask2, mask3;
272 if (!s || s->magic != HDLCDRV_MAGIC)
274 if (test_and_set_bit(0, &s->hdlctx.in_hdlc_tx))
277 if (s->hdlctx.numbits >= 16) {
278 if (hdlcdrv_hbuf_full(&s->hdlctx.hbuf)) {
279 clear_bit(0, &s->hdlctx.in_hdlc_tx);
282 hdlcdrv_hbuf_put(&s->hdlctx.hbuf, s->hdlctx.bitbuf);
283 s->hdlctx.bitbuf >>= 16;
284 s->hdlctx.numbits -= 16;
286 switch (s->hdlctx.tx_state) {
288 clear_bit(0, &s->hdlctx.in_hdlc_tx);
292 if (s->hdlctx.numflags) {
293 s->hdlctx.numflags--;
295 0x7e7e << s->hdlctx.numbits;
296 s->hdlctx.numbits += 16;
299 if (s->hdlctx.tx_state == 1) {
300 clear_bit(0, &s->hdlctx.in_hdlc_tx);
303 if (!(skb = s->skb)) {
304 int flgs = tenms_to_2flags(s, s->ch_params.tx_tail);
307 s->hdlctx.tx_state = 1;
308 s->hdlctx.numflags = flgs;
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);
320 skb_copy_from_linear_data_offset(skb, 1,
323 dev_kfree_skb_irq(skb);
324 s->hdlctx.bp = s->hdlctx.buffer;
325 append_crc_ccitt(s->hdlctx.buffer, pkt_len);
326 s->hdlctx.len = pkt_len+2; /* the appended CRC */
327 s->hdlctx.tx_state = 2;
328 s->hdlctx.bitstream = 0;
329 s->stats.tx_packets++;
332 if (!s->hdlctx.len) {
333 s->hdlctx.tx_state = 0;
334 s->hdlctx.numflags = 1;
338 s->hdlctx.bitbuf |= *s->hdlctx.bp <<
340 s->hdlctx.bitstream >>= 8;
341 s->hdlctx.bitstream |= (*s->hdlctx.bp++) << 16;
344 mask3 = 0xffffffff >> (31-s->hdlctx.numbits);
345 s->hdlctx.numbits += 8;
346 for(i = 0; i < 8; i++, mask1 <<= 1, mask2 <<= 1,
347 mask3 = (mask3 << 1) | 1) {
348 if ((s->hdlctx.bitstream & mask1) != mask1)
350 s->hdlctx.bitstream &= ~mask2;
352 (s->hdlctx.bitbuf & mask3) |
356 mask3 = (mask3 << 1) | 1;
363 /* ---------------------------------------------------------------------- */
365 static void start_tx(struct net_device *dev, struct hdlcdrv_state *s)
367 s->hdlctx.tx_state = 0;
368 s->hdlctx.numflags = tenms_to_2flags(s, s->ch_params.tx_delay);
369 s->hdlctx.bitbuf = s->hdlctx.bitstream = s->hdlctx.numbits = 0;
370 hdlcdrv_transmitter(dev, s);
375 /* ---------------------------------------------------------------------- */
377 void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
379 if (!s || s->magic != HDLCDRV_MAGIC || s->hdlctx.ptt || !s->skb)
381 if (s->ch_params.fulldup) {
386 s->hdlctx.slotcnt = s->ch_params.slottime;
389 if ((--s->hdlctx.slotcnt) > 0)
391 s->hdlctx.slotcnt = s->ch_params.slottime;
392 if ((random32() % 256) > s->ch_params.ppersist)
397 /* --------------------------------------------------------------------- */
399 * ===================== network driver interface =========================
402 static int hdlcdrv_send_packet(struct sk_buff *skb, struct net_device *dev)
404 struct hdlcdrv_state *sm = netdev_priv(dev);
406 if (skb->data[0] != 0) {
407 do_kiss_params(sm, skb->data, skb->len);
413 netif_stop_queue(dev);
418 /* --------------------------------------------------------------------- */
420 static int hdlcdrv_set_mac_address(struct net_device *dev, void *addr)
422 struct sockaddr *sa = (struct sockaddr *)addr;
424 /* addr is an AX.25 shifted ASCII mac address */
425 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
429 /* --------------------------------------------------------------------- */
431 static struct net_device_stats *hdlcdrv_get_stats(struct net_device *dev)
433 struct hdlcdrv_state *sm = netdev_priv(dev);
436 * Get the current statistics. This may be called with the
437 * card open or closed.
442 /* --------------------------------------------------------------------- */
444 * Open/initialize the board. This is called (in the current kernel)
445 * sometime after booting when the 'ifconfig' program is run.
447 * This routine should set everything up anew at each open, even
448 * registers that "should" only need to be set once at boot, so that
449 * there is non-reboot way to recover if something goes wrong.
452 static int hdlcdrv_open(struct net_device *dev)
454 struct hdlcdrv_state *s = netdev_priv(dev);
457 if (!s->ops || !s->ops->open)
461 * initialise some variables
464 s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
465 s->hdlcrx.in_hdlc_rx = 0;
466 s->hdlcrx.rx_state = 0;
468 s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
469 s->hdlctx.in_hdlc_tx = 0;
470 s->hdlctx.tx_state = 1;
471 s->hdlctx.numflags = 0;
472 s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
474 s->hdlctx.slotcnt = s->ch_params.slottime;
475 s->hdlctx.calibrate = 0;
477 i = s->ops->open(dev);
480 netif_start_queue(dev);
484 /* --------------------------------------------------------------------- */
486 * The inverse routine to hdlcdrv_open().
489 static int hdlcdrv_close(struct net_device *dev)
491 struct hdlcdrv_state *s = netdev_priv(dev);
494 netif_stop_queue(dev);
496 if (s->ops && s->ops->close)
497 i = s->ops->close(dev);
499 dev_kfree_skb(s->skb);
505 /* --------------------------------------------------------------------- */
507 static int hdlcdrv_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
509 struct hdlcdrv_state *s = netdev_priv(dev);
510 struct hdlcdrv_ioctl bi;
512 if (cmd != SIOCDEVPRIVATE) {
513 if (s->ops && s->ops->ioctl)
514 return s->ops->ioctl(dev, ifr, &bi, cmd);
517 if (copy_from_user(&bi, ifr->ifr_data, sizeof(bi)))
522 if (s->ops && s->ops->ioctl)
523 return s->ops->ioctl(dev, ifr, &bi, cmd);
526 case HDLCDRVCTL_GETCHANNELPAR:
527 bi.data.cp.tx_delay = s->ch_params.tx_delay;
528 bi.data.cp.tx_tail = s->ch_params.tx_tail;
529 bi.data.cp.slottime = s->ch_params.slottime;
530 bi.data.cp.ppersist = s->ch_params.ppersist;
531 bi.data.cp.fulldup = s->ch_params.fulldup;
534 case HDLCDRVCTL_SETCHANNELPAR:
535 if (!capable(CAP_NET_ADMIN))
537 s->ch_params.tx_delay = bi.data.cp.tx_delay;
538 s->ch_params.tx_tail = bi.data.cp.tx_tail;
539 s->ch_params.slottime = bi.data.cp.slottime;
540 s->ch_params.ppersist = bi.data.cp.ppersist;
541 s->ch_params.fulldup = bi.data.cp.fulldup;
542 s->hdlctx.slotcnt = 1;
545 case HDLCDRVCTL_GETMODEMPAR:
546 bi.data.mp.iobase = dev->base_addr;
547 bi.data.mp.irq = dev->irq;
548 bi.data.mp.dma = dev->dma;
549 bi.data.mp.dma2 = s->ptt_out.dma2;
550 bi.data.mp.seriobase = s->ptt_out.seriobase;
551 bi.data.mp.pariobase = s->ptt_out.pariobase;
552 bi.data.mp.midiiobase = s->ptt_out.midiiobase;
555 case HDLCDRVCTL_SETMODEMPAR:
556 if ((!capable(CAP_SYS_RAWIO)) || netif_running(dev))
558 dev->base_addr = bi.data.mp.iobase;
559 dev->irq = bi.data.mp.irq;
560 dev->dma = bi.data.mp.dma;
561 s->ptt_out.dma2 = bi.data.mp.dma2;
562 s->ptt_out.seriobase = bi.data.mp.seriobase;
563 s->ptt_out.pariobase = bi.data.mp.pariobase;
564 s->ptt_out.midiiobase = bi.data.mp.midiiobase;
567 case HDLCDRVCTL_GETSTAT:
568 bi.data.cs.ptt = hdlcdrv_ptt(s);
569 bi.data.cs.dcd = s->hdlcrx.dcd;
570 bi.data.cs.ptt_keyed = s->ptt_keyed;
571 bi.data.cs.tx_packets = s->stats.tx_packets;
572 bi.data.cs.tx_errors = s->stats.tx_errors;
573 bi.data.cs.rx_packets = s->stats.rx_packets;
574 bi.data.cs.rx_errors = s->stats.rx_errors;
577 case HDLCDRVCTL_OLDGETSTAT:
578 bi.data.ocs.ptt = hdlcdrv_ptt(s);
579 bi.data.ocs.dcd = s->hdlcrx.dcd;
580 bi.data.ocs.ptt_keyed = s->ptt_keyed;
583 case HDLCDRVCTL_CALIBRATE:
584 if(!capable(CAP_SYS_RAWIO))
586 s->hdlctx.calibrate = bi.data.calibrate * s->par.bitrate / 16;
589 case HDLCDRVCTL_GETSAMPLES:
590 #ifndef HDLCDRV_DEBUG
592 #else /* HDLCDRV_DEBUG */
593 if (s->bitbuf_channel.rd == s->bitbuf_channel.wr)
596 s->bitbuf_channel.buffer[s->bitbuf_channel.rd];
597 s->bitbuf_channel.rd = (s->bitbuf_channel.rd+1) %
598 sizeof(s->bitbuf_channel.buffer);
600 #endif /* HDLCDRV_DEBUG */
602 case HDLCDRVCTL_GETBITS:
603 #ifndef HDLCDRV_DEBUG
605 #else /* HDLCDRV_DEBUG */
606 if (s->bitbuf_hdlc.rd == s->bitbuf_hdlc.wr)
609 s->bitbuf_hdlc.buffer[s->bitbuf_hdlc.rd];
610 s->bitbuf_hdlc.rd = (s->bitbuf_hdlc.rd+1) %
611 sizeof(s->bitbuf_hdlc.buffer);
613 #endif /* HDLCDRV_DEBUG */
615 case HDLCDRVCTL_DRIVERNAME:
616 if (s->ops && s->ops->drvname) {
617 strncpy(bi.data.drivername, s->ops->drvname,
618 sizeof(bi.data.drivername));
621 bi.data.drivername[0] = '\0';
625 if (copy_to_user(ifr->ifr_data, &bi, sizeof(bi)))
631 /* --------------------------------------------------------------------- */
634 * Initialize fields in hdlcdrv
636 static void hdlcdrv_setup(struct net_device *dev)
638 static const struct hdlcdrv_channel_params dflt_ch_params = {
641 struct hdlcdrv_state *s = netdev_priv(dev);
644 * initialize the hdlcdrv_state struct
646 s->ch_params = dflt_ch_params;
649 spin_lock_init(&s->hdlcrx.hbuf.lock);
650 s->hdlcrx.hbuf.rd = s->hdlcrx.hbuf.wr = 0;
651 s->hdlcrx.in_hdlc_rx = 0;
652 s->hdlcrx.rx_state = 0;
654 spin_lock_init(&s->hdlctx.hbuf.lock);
655 s->hdlctx.hbuf.rd = s->hdlctx.hbuf.wr = 0;
656 s->hdlctx.in_hdlc_tx = 0;
657 s->hdlctx.tx_state = 1;
658 s->hdlctx.numflags = 0;
659 s->hdlctx.bitstream = s->hdlctx.bitbuf = s->hdlctx.numbits = 0;
661 s->hdlctx.slotcnt = s->ch_params.slottime;
662 s->hdlctx.calibrate = 0;
665 s->bitbuf_channel.rd = s->bitbuf_channel.wr = 0;
666 s->bitbuf_channel.shreg = 0x80;
668 s->bitbuf_hdlc.rd = s->bitbuf_hdlc.wr = 0;
669 s->bitbuf_hdlc.shreg = 0x80;
670 #endif /* HDLCDRV_DEBUG */
673 * initialize the device struct
675 dev->open = hdlcdrv_open;
676 dev->stop = hdlcdrv_close;
677 dev->do_ioctl = hdlcdrv_ioctl;
678 dev->hard_start_xmit = hdlcdrv_send_packet;
679 dev->get_stats = hdlcdrv_get_stats;
681 /* Fill in the fields of the device structure */
685 dev->header_ops = &ax25_header_ops;
686 dev->set_mac_address = hdlcdrv_set_mac_address;
688 dev->type = ARPHRD_AX25; /* AF_AX25 device */
689 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
690 dev->mtu = AX25_DEF_PACLEN; /* eth_mtu is the default */
691 dev->addr_len = AX25_ADDR_LEN; /* sizeof an ax.25 address */
692 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
693 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
694 dev->tx_queue_len = 16;
697 /* --------------------------------------------------------------------- */
698 struct net_device *hdlcdrv_register(const struct hdlcdrv_ops *ops,
699 unsigned int privsize, const char *ifname,
700 unsigned int baseaddr, unsigned int irq,
703 struct net_device *dev;
704 struct hdlcdrv_state *s;
709 if (privsize < sizeof(struct hdlcdrv_state))
710 privsize = sizeof(struct hdlcdrv_state);
712 dev = alloc_netdev(privsize, ifname, hdlcdrv_setup);
714 return ERR_PTR(-ENOMEM);
717 * initialize part of the hdlcdrv_state struct
719 s = netdev_priv(dev);
720 s->magic = HDLCDRV_MAGIC;
722 dev->base_addr = baseaddr;
726 err = register_netdev(dev);
728 printk(KERN_WARNING "hdlcdrv: cannot register net "
729 "device %s\n", dev->name);
736 /* --------------------------------------------------------------------- */
738 void hdlcdrv_unregister(struct net_device *dev)
740 struct hdlcdrv_state *s = netdev_priv(dev);
742 BUG_ON(s->magic != HDLCDRV_MAGIC);
744 if (s->opened && s->ops->close)
746 unregister_netdev(dev);
751 /* --------------------------------------------------------------------- */
753 EXPORT_SYMBOL(hdlcdrv_receiver);
754 EXPORT_SYMBOL(hdlcdrv_transmitter);
755 EXPORT_SYMBOL(hdlcdrv_arbitrate);
756 EXPORT_SYMBOL(hdlcdrv_register);
757 EXPORT_SYMBOL(hdlcdrv_unregister);
759 /* --------------------------------------------------------------------- */
761 static int __init hdlcdrv_init_driver(void)
763 printk(KERN_INFO "hdlcdrv: (C) 1996-2000 Thomas Sailer HB9JNX/AE4WA\n");
764 printk(KERN_INFO "hdlcdrv: version 0.8 compiled " __TIME__ " " __DATE__ "\n");
768 /* --------------------------------------------------------------------- */
770 static void __exit hdlcdrv_cleanup_driver(void)
772 printk(KERN_INFO "hdlcdrv: cleanup\n");
775 /* --------------------------------------------------------------------- */
777 MODULE_AUTHOR("Thomas M. Sailer, sailer@ife.ee.ethz.ch, hb9jnx@hb9w.che.eu");
778 MODULE_DESCRIPTION("Packet Radio network interface HDLC encoder/decoder");
779 MODULE_LICENSE("GPL");
780 module_init(hdlcdrv_init_driver);
781 module_exit(hdlcdrv_cleanup_driver);
783 /* --------------------------------------------------------------------- */