1 /*
2 * slcan.c - serial line CAN interface driver (using tty line discipline)
3 *
4 * This file is derived from linux/drivers/net/slip/slip.c
5 *
6 * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
7 * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
8 * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net>
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it
23 * at http://www.gnu.org/licenses/gpl.html
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
36 * DAMAGE.
37 *
38 */
39
40 #include <linux/module.h>
41 #include <linux/moduleparam.h>
42
43 #include <linux/uaccess.h>
44 #include <linux/bitops.h>
45 #include <linux/string.h>
46 #include <linux/tty.h>
47 #include <linux/errno.h>
48 #include <linux/netdevice.h>
49 #include <linux/skbuff.h>
50 #include <linux/rtnetlink.h>
51 #include <linux/if_arp.h>
52 #include <linux/if_ether.h>
53 #include <linux/sched.h>
54 #include <linux/delay.h>
55 #include <linux/init.h>
56 #include <linux/kernel.h>
57 #include <linux/can.h>
58 #include <linux/can/skb.h>
59
60 static __initconst const char banner[] =
61 KERN_INFO "slcan: serial line CAN interface driver\n";
62
63 MODULE_ALIAS_LDISC(N_SLCAN);
64 MODULE_DESCRIPTION("serial line CAN interface");
65 MODULE_LICENSE("GPL");
66 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
67
68 #define SLCAN_MAGIC 0x53CA
69
70 static int maxdev = 10; /* MAX number of SLCAN channels;
71 This can be overridden with
72 insmod slcan.ko maxdev=nnn */
73 module_param(maxdev, int, 0);
74 MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
75
76 /* maximum rx buffer len: extended CAN frame with timestamp */
77 #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
78
79 struct slcan {
80 int magic;
81
82 /* Various fields. */
83 struct tty_struct *tty; /* ptr to TTY structure */
84 struct net_device *dev; /* easy for intr handling */
85 spinlock_t lock;
86
87 /* These are pointers to the malloc()ed frame buffers. */
88 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
89 int rcount; /* received chars counter */
90 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
91 unsigned char *xhead; /* pointer to next XMIT byte */
92 int xleft; /* bytes left in XMIT queue */
93
94 unsigned long flags; /* Flag values/ mode etc */
95 #define SLF_INUSE 0 /* Channel in use */
96 #define SLF_ERROR 1 /* Parity, etc. error */
97 };
98
99 static struct net_device **slcan_devs;
100
101 /************************************************************************
102 * SLCAN ENCAPSULATION FORMAT *
103 ************************************************************************/
104
105 /*
106 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
107 * frame format) a data length code (can_dlc) which can be from 0 to 8
108 * and up to <can_dlc> data bytes as payload.
109 * Additionally a CAN frame may become a remote transmission frame if the
110 * RTR-bit is set. This causes another ECU to send a CAN frame with the
111 * given can_id.
112 *
113 * The SLCAN ASCII representation of these different frame types is:
114 * <type> <id> <dlc> <data>*
115 *
116 * Extended frames (29 bit) are defined by capital characters in the type.
117 * RTR frames are defined as 'r' types - normal frames have 't' type:
118 * t => 11 bit data frame
119 * r => 11 bit RTR frame
120 * T => 29 bit data frame
121 * R => 29 bit RTR frame
122 *
123 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
124 * The <dlc> is a one byte ASCII number ('0' - '8')
125 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
126 *
127 * Examples:
128 *
129 * t1230 : can_id 0x123, can_dlc 0, no data
130 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
131 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
132 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
133 *
134 */
135
136 /************************************************************************
137 * STANDARD SLCAN DECAPSULATION *
138 ************************************************************************/
139
140 /* Send one completely decapsulated can_frame to the network layer */
slc_bump(struct slcan * sl)141 static void slc_bump(struct slcan *sl)
142 {
143 struct sk_buff *skb;
144 struct can_frame cf;
145 int i, dlc_pos, tmp;
146 unsigned long ultmp;
147 char cmd = sl->rbuff[0];
148
149 if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
150 return;
151
152 if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
153 dlc_pos = 4; /* dlc position tiiid */
154 else
155 dlc_pos = 9; /* dlc position Tiiiiiiiid */
156
157 if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
158 return;
159
160 cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
161
162 sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
163
164 if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
165 return;
166
167 cf.can_id = ultmp;
168
169 if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
170 cf.can_id |= CAN_EFF_FLAG;
171
172 if ((cmd | 0x20) == 'r') /* RTR frame */
173 cf.can_id |= CAN_RTR_FLAG;
174
175 *(u64 *) (&cf.data) = 0; /* clear payload */
176
177 for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
178 tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
179 if (tmp < 0)
180 return;
181 cf.data[i] = (tmp << 4);
182 tmp = hex_to_bin(sl->rbuff[dlc_pos++]);
183 if (tmp < 0)
184 return;
185 cf.data[i] |= tmp;
186 }
187
188 skb = dev_alloc_skb(sizeof(struct can_frame) +
189 sizeof(struct can_skb_priv));
190 if (!skb)
191 return;
192
193 skb->dev = sl->dev;
194 skb->protocol = htons(ETH_P_CAN);
195 skb->pkt_type = PACKET_BROADCAST;
196 skb->ip_summed = CHECKSUM_UNNECESSARY;
197
198 can_skb_reserve(skb);
199 can_skb_prv(skb)->ifindex = sl->dev->ifindex;
200
201 memcpy(skb_put(skb, sizeof(struct can_frame)),
202 &cf, sizeof(struct can_frame));
203 netif_rx_ni(skb);
204
205 sl->dev->stats.rx_packets++;
206 sl->dev->stats.rx_bytes += cf.can_dlc;
207 }
208
209 /* parse tty input stream */
slcan_unesc(struct slcan * sl,unsigned char s)210 static void slcan_unesc(struct slcan *sl, unsigned char s)
211 {
212
213 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
214 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
215 (sl->rcount > 4)) {
216 slc_bump(sl);
217 }
218 sl->rcount = 0;
219 } else {
220 if (!test_bit(SLF_ERROR, &sl->flags)) {
221 if (sl->rcount < SLC_MTU) {
222 sl->rbuff[sl->rcount++] = s;
223 return;
224 } else {
225 sl->dev->stats.rx_over_errors++;
226 set_bit(SLF_ERROR, &sl->flags);
227 }
228 }
229 }
230 }
231
232 /************************************************************************
233 * STANDARD SLCAN ENCAPSULATION *
234 ************************************************************************/
235
236 /* Encapsulate one can_frame and stuff into a TTY queue. */
slc_encaps(struct slcan * sl,struct can_frame * cf)237 static void slc_encaps(struct slcan *sl, struct can_frame *cf)
238 {
239 int actual, idx, i;
240 char cmd;
241
242 if (cf->can_id & CAN_RTR_FLAG)
243 cmd = 'R'; /* becomes 'r' in standard frame format */
244 else
245 cmd = 'T'; /* becomes 't' in standard frame format */
246
247 if (cf->can_id & CAN_EFF_FLAG)
248 sprintf(sl->xbuff, "%c%08X%d", cmd,
249 cf->can_id & CAN_EFF_MASK, cf->can_dlc);
250 else
251 sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20,
252 cf->can_id & CAN_SFF_MASK, cf->can_dlc);
253
254 idx = strlen(sl->xbuff);
255
256 for (i = 0; i < cf->can_dlc; i++)
257 sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
258
259 strcat(sl->xbuff, "\r"); /* add terminating character */
260
261 /* Order of next two lines is *very* important.
262 * When we are sending a little amount of data,
263 * the transfer may be completed inside the ops->write()
264 * routine, because it's running with interrupts enabled.
265 * In this case we *never* got WRITE_WAKEUP event,
266 * if we did not request it before write operation.
267 * 14 Oct 1994 Dmitry Gorodchanin.
268 */
269 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
270 actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
271 sl->xleft = strlen(sl->xbuff) - actual;
272 sl->xhead = sl->xbuff + actual;
273 sl->dev->stats.tx_bytes += cf->can_dlc;
274 }
275
276 /*
277 * Called by the driver when there's room for more data. If we have
278 * more packets to send, we send them here.
279 */
slcan_write_wakeup(struct tty_struct * tty)280 static void slcan_write_wakeup(struct tty_struct *tty)
281 {
282 int actual;
283 struct slcan *sl = (struct slcan *) tty->disc_data;
284
285 /* First make sure we're connected. */
286 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
287 return;
288
289 if (sl->xleft <= 0) {
290 /* Now serial buffer is almost free & we can start
291 * transmission of another packet */
292 sl->dev->stats.tx_packets++;
293 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
294 netif_wake_queue(sl->dev);
295 return;
296 }
297
298 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
299 sl->xleft -= actual;
300 sl->xhead += actual;
301 }
302
303 /* Send a can_frame to a TTY queue. */
slc_xmit(struct sk_buff * skb,struct net_device * dev)304 static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
305 {
306 struct slcan *sl = netdev_priv(dev);
307
308 if (skb->len != sizeof(struct can_frame))
309 goto out;
310
311 spin_lock(&sl->lock);
312 if (!netif_running(dev)) {
313 spin_unlock(&sl->lock);
314 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
315 goto out;
316 }
317 if (sl->tty == NULL) {
318 spin_unlock(&sl->lock);
319 goto out;
320 }
321
322 netif_stop_queue(sl->dev);
323 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
324 spin_unlock(&sl->lock);
325
326 out:
327 kfree_skb(skb);
328 return NETDEV_TX_OK;
329 }
330
331
332 /******************************************
333 * Routines looking at netdevice side.
334 ******************************************/
335
336 /* Netdevice UP -> DOWN routine */
slc_close(struct net_device * dev)337 static int slc_close(struct net_device *dev)
338 {
339 struct slcan *sl = netdev_priv(dev);
340
341 spin_lock_bh(&sl->lock);
342 if (sl->tty) {
343 /* TTY discipline is running. */
344 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
345 }
346 netif_stop_queue(dev);
347 sl->rcount = 0;
348 sl->xleft = 0;
349 spin_unlock_bh(&sl->lock);
350
351 return 0;
352 }
353
354 /* Netdevice DOWN -> UP routine */
slc_open(struct net_device * dev)355 static int slc_open(struct net_device *dev)
356 {
357 struct slcan *sl = netdev_priv(dev);
358
359 if (sl->tty == NULL)
360 return -ENODEV;
361
362 sl->flags &= (1 << SLF_INUSE);
363 netif_start_queue(dev);
364 return 0;
365 }
366
367 /* Hook the destructor so we can free slcan devs at the right point in time */
slc_free_netdev(struct net_device * dev)368 static void slc_free_netdev(struct net_device *dev)
369 {
370 int i = dev->base_addr;
371 free_netdev(dev);
372 slcan_devs[i] = NULL;
373 }
374
375 static const struct net_device_ops slc_netdev_ops = {
376 .ndo_open = slc_open,
377 .ndo_stop = slc_close,
378 .ndo_start_xmit = slc_xmit,
379 };
380
slc_setup(struct net_device * dev)381 static void slc_setup(struct net_device *dev)
382 {
383 dev->netdev_ops = &slc_netdev_ops;
384 dev->destructor = slc_free_netdev;
385
386 dev->hard_header_len = 0;
387 dev->addr_len = 0;
388 dev->tx_queue_len = 10;
389
390 dev->mtu = sizeof(struct can_frame);
391 dev->type = ARPHRD_CAN;
392
393 /* New-style flags. */
394 dev->flags = IFF_NOARP;
395 dev->features = NETIF_F_HW_CSUM;
396 }
397
398 /******************************************
399 Routines looking at TTY side.
400 ******************************************/
401
402 /*
403 * Handle the 'receiver data ready' interrupt.
404 * This function is called by the 'tty_io' module in the kernel when
405 * a block of SLCAN data has been received, which can now be decapsulated
406 * and sent on to some IP layer for further processing. This will not
407 * be re-entered while running but other ldisc functions may be called
408 * in parallel
409 */
410
slcan_receive_buf(struct tty_struct * tty,const unsigned char * cp,char * fp,int count)411 static void slcan_receive_buf(struct tty_struct *tty,
412 const unsigned char *cp, char *fp, int count)
413 {
414 struct slcan *sl = (struct slcan *) tty->disc_data;
415
416 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
417 return;
418
419 /* Read the characters out of the buffer */
420 while (count--) {
421 if (fp && *fp++) {
422 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
423 sl->dev->stats.rx_errors++;
424 cp++;
425 continue;
426 }
427 slcan_unesc(sl, *cp++);
428 }
429 }
430
431 /************************************
432 * slcan_open helper routines.
433 ************************************/
434
435 /* Collect hanged up channels */
slc_sync(void)436 static void slc_sync(void)
437 {
438 int i;
439 struct net_device *dev;
440 struct slcan *sl;
441
442 for (i = 0; i < maxdev; i++) {
443 dev = slcan_devs[i];
444 if (dev == NULL)
445 break;
446
447 sl = netdev_priv(dev);
448 if (sl->tty)
449 continue;
450 if (dev->flags & IFF_UP)
451 dev_close(dev);
452 }
453 }
454
455 /* Find a free SLCAN channel, and link in this `tty' line. */
slc_alloc(dev_t line)456 static struct slcan *slc_alloc(dev_t line)
457 {
458 int i;
459 char name[IFNAMSIZ];
460 struct net_device *dev = NULL;
461 struct slcan *sl;
462
463 for (i = 0; i < maxdev; i++) {
464 dev = slcan_devs[i];
465 if (dev == NULL)
466 break;
467
468 }
469
470 /* Sorry, too many, all slots in use */
471 if (i >= maxdev)
472 return NULL;
473
474 sprintf(name, "slcan%d", i);
475 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
476 if (!dev)
477 return NULL;
478
479 dev->base_addr = i;
480 sl = netdev_priv(dev);
481
482 /* Initialize channel control data */
483 sl->magic = SLCAN_MAGIC;
484 sl->dev = dev;
485 spin_lock_init(&sl->lock);
486 slcan_devs[i] = dev;
487
488 return sl;
489 }
490
491 /*
492 * Open the high-level part of the SLCAN channel.
493 * This function is called by the TTY module when the
494 * SLCAN line discipline is called for. Because we are
495 * sure the tty line exists, we only have to link it to
496 * a free SLCAN channel...
497 *
498 * Called in process context serialized from other ldisc calls.
499 */
500
slcan_open(struct tty_struct * tty)501 static int slcan_open(struct tty_struct *tty)
502 {
503 struct slcan *sl;
504 int err;
505
506 if (!capable(CAP_NET_ADMIN))
507 return -EPERM;
508
509 if (tty->ops->write == NULL)
510 return -EOPNOTSUPP;
511
512 /* RTnetlink lock is misused here to serialize concurrent
513 opens of slcan channels. There are better ways, but it is
514 the simplest one.
515 */
516 rtnl_lock();
517
518 /* Collect hanged up channels. */
519 slc_sync();
520
521 sl = tty->disc_data;
522
523 err = -EEXIST;
524 /* First make sure we're not already connected. */
525 if (sl && sl->magic == SLCAN_MAGIC)
526 goto err_exit;
527
528 /* OK. Find a free SLCAN channel to use. */
529 err = -ENFILE;
530 sl = slc_alloc(tty_devnum(tty));
531 if (sl == NULL)
532 goto err_exit;
533
534 sl->tty = tty;
535 tty->disc_data = sl;
536
537 if (!test_bit(SLF_INUSE, &sl->flags)) {
538 /* Perform the low-level SLCAN initialization. */
539 sl->rcount = 0;
540 sl->xleft = 0;
541
542 set_bit(SLF_INUSE, &sl->flags);
543
544 err = register_netdevice(sl->dev);
545 if (err)
546 goto err_free_chan;
547 }
548
549 /* Done. We have linked the TTY line to a channel. */
550 rtnl_unlock();
551 tty->receive_room = 65536; /* We don't flow control */
552
553 /* TTY layer expects 0 on success */
554 return 0;
555
556 err_free_chan:
557 sl->tty = NULL;
558 tty->disc_data = NULL;
559 clear_bit(SLF_INUSE, &sl->flags);
560
561 err_exit:
562 rtnl_unlock();
563
564 /* Count references from TTY module */
565 return err;
566 }
567
568 /*
569 * Close down a SLCAN channel.
570 * This means flushing out any pending queues, and then returning. This
571 * call is serialized against other ldisc functions.
572 *
573 * We also use this method for a hangup event.
574 */
575
slcan_close(struct tty_struct * tty)576 static void slcan_close(struct tty_struct *tty)
577 {
578 struct slcan *sl = (struct slcan *) tty->disc_data;
579
580 /* First make sure we're connected. */
581 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
582 return;
583
584 tty->disc_data = NULL;
585 sl->tty = NULL;
586
587 /* Flush network side */
588 unregister_netdev(sl->dev);
589 /* This will complete via sl_free_netdev */
590 }
591
slcan_hangup(struct tty_struct * tty)592 static int slcan_hangup(struct tty_struct *tty)
593 {
594 slcan_close(tty);
595 return 0;
596 }
597
598 /* Perform I/O control on an active SLCAN channel. */
slcan_ioctl(struct tty_struct * tty,struct file * file,unsigned int cmd,unsigned long arg)599 static int slcan_ioctl(struct tty_struct *tty, struct file *file,
600 unsigned int cmd, unsigned long arg)
601 {
602 struct slcan *sl = (struct slcan *) tty->disc_data;
603 unsigned int tmp;
604
605 /* First make sure we're connected. */
606 if (!sl || sl->magic != SLCAN_MAGIC)
607 return -EINVAL;
608
609 switch (cmd) {
610 case SIOCGIFNAME:
611 tmp = strlen(sl->dev->name) + 1;
612 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
613 return -EFAULT;
614 return 0;
615
616 case SIOCSIFHWADDR:
617 return -EINVAL;
618
619 default:
620 return tty_mode_ioctl(tty, file, cmd, arg);
621 }
622 }
623
624 static struct tty_ldisc_ops slc_ldisc = {
625 .owner = THIS_MODULE,
626 .magic = TTY_LDISC_MAGIC,
627 .name = "slcan",
628 .open = slcan_open,
629 .close = slcan_close,
630 .hangup = slcan_hangup,
631 .ioctl = slcan_ioctl,
632 .receive_buf = slcan_receive_buf,
633 .write_wakeup = slcan_write_wakeup,
634 };
635
slcan_init(void)636 static int __init slcan_init(void)
637 {
638 int status;
639
640 if (maxdev < 4)
641 maxdev = 4; /* Sanity */
642
643 printk(banner);
644 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
645
646 slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
647 if (!slcan_devs)
648 return -ENOMEM;
649
650 /* Fill in our line protocol discipline, and register it */
651 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
652 if (status) {
653 printk(KERN_ERR "slcan: can't register line discipline\n");
654 kfree(slcan_devs);
655 }
656 return status;
657 }
658
slcan_exit(void)659 static void __exit slcan_exit(void)
660 {
661 int i;
662 struct net_device *dev;
663 struct slcan *sl;
664 unsigned long timeout = jiffies + HZ;
665 int busy = 0;
666
667 if (slcan_devs == NULL)
668 return;
669
670 /* First of all: check for active disciplines and hangup them.
671 */
672 do {
673 if (busy)
674 msleep_interruptible(100);
675
676 busy = 0;
677 for (i = 0; i < maxdev; i++) {
678 dev = slcan_devs[i];
679 if (!dev)
680 continue;
681 sl = netdev_priv(dev);
682 spin_lock_bh(&sl->lock);
683 if (sl->tty) {
684 busy++;
685 tty_hangup(sl->tty);
686 }
687 spin_unlock_bh(&sl->lock);
688 }
689 } while (busy && time_before(jiffies, timeout));
690
691 /* FIXME: hangup is async so we should wait when doing this second
692 phase */
693
694 for (i = 0; i < maxdev; i++) {
695 dev = slcan_devs[i];
696 if (!dev)
697 continue;
698 slcan_devs[i] = NULL;
699
700 sl = netdev_priv(dev);
701 if (sl->tty) {
702 printk(KERN_ERR "%s: tty discipline still running\n",
703 dev->name);
704 /* Intentionally leak the control block. */
705 dev->destructor = NULL;
706 }
707
708 unregister_netdev(dev);
709 }
710
711 kfree(slcan_devs);
712 slcan_devs = NULL;
713
714 i = tty_unregister_ldisc(N_SLCAN);
715 if (i)
716 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
717 }
718
719 module_init(slcan_init);
720 module_exit(slcan_exit);
721