2 * slcan.c - serial line CAN interface driver (using tty line discipline)
4 * This file is derived from linux/drivers/net/slip.c
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>
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.
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.
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
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
38 * Send feedback to <socketcan-users@lists.berlios.de>
42 #include <linux/version.h>
43 #include <linux/module.h>
44 #include <linux/moduleparam.h>
46 #include <asm/system.h>
47 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17)
48 #include <linux/uaccess.h>
50 #include <asm/uaccess.h>
52 #include <linux/bitops.h>
53 #include <linux/sched.h>
54 #include <linux/string.h>
56 #include <linux/interrupt.h>
58 #include <linux/tty.h>
59 #include <linux/errno.h>
60 #include <linux/netdevice.h>
61 #include <linux/etherdevice.h>
62 #include <linux/skbuff.h>
63 #include <linux/rtnetlink.h>
64 #include <linux/if_arp.h>
65 #include <linux/if_ether.h>
66 #include <linux/if_slip.h>
67 #include <linux/delay.h>
68 #include <linux/init.h>
69 #include <socketcan/can.h>
71 #include <socketcan/can/version.h> /* for RCSID. Removed by mkpatch script */
74 static __initdata const char banner[] =
75 KERN_INFO "slcan: serial line CAN interface driver\n";
77 MODULE_ALIAS_LDISC(N_SLCAN);
78 MODULE_DESCRIPTION("serial line CAN interface");
79 MODULE_LICENSE("GPL");
80 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
81 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,14)
82 static inline void *kzalloc(size_t size, unsigned int __nocast flags)
84 void *ret = kmalloc(size, flags);
90 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
92 #error Your kernel does not support tty line discipline N_SLCAN
95 * As there is currently no line discipline N_SLCAN in the mainstream kernel
96 * you will have to modify two kernel includes & recompile the kernel.
98 * Add this in include/asm/termios.h after the definition of N_HCI:
101 * Increment NR_LDICS in include/linux/tty.h from 16 to 17
103 * NEW: Since Kernel 2.6.21 you only have to change include/linux/tty.h
105 * HACK for precompiled Kernels:
107 * In order to use the slcan driver without rebuilding the kernel, the slcan
108 * driver must be compiled to use an existing line discipline.
109 * The N_MOUSE line discipline is documented to be free for custom use and
110 * using it *should* not cause any side effect.
112 * Then, before compiling the slcan driver, add a -DN_SLCAN=N_MOUSE
113 * compilation option in its Makefile. The slcan_attach tool must(!!) also be
114 * rebuild to use the right value for N_SLCAN. This workaround will allow
115 * to use the slcan driver with an existing kernel.
119 #define SLCAN_MAGIC 0x53CA
121 static int maxdev = 10; /* MAX number of SLCAN channels;
122 This can be overridden with
123 insmod slcan.ko maxdev=nnn */
124 module_param(maxdev, int, 0);
125 MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
127 /* maximum rx buffer len: extended CAN frame with timestamp */
128 #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
133 /* Various fields. */
134 struct tty_struct *tty; /* ptr to TTY structure */
135 struct net_device *dev; /* easy for intr handling */
138 /* These are pointers to the malloc()ed frame buffers. */
139 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
140 int rcount; /* received chars counter */
141 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
142 unsigned char *xhead; /* pointer to next XMIT byte */
143 int xleft; /* bytes left in XMIT queue */
145 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
146 /* SLCAN interface statistics. */
147 struct net_device_stats stats;
150 unsigned long flags; /* Flag values/ mode etc */
151 #define SLF_INUSE 0 /* Channel in use */
152 #define SLF_ERROR 1 /* Parity, etc. error */
154 unsigned char leased;
159 static struct net_device **slcan_devs;
161 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
162 /* Netdevice get statistics request */
163 static struct net_device_stats *slc_get_stats(struct net_device *dev)
165 struct slcan *sl = netdev_priv(dev);
171 /************************************************************************
172 * SLCAN ENCAPSULATION FORMAT *
173 ************************************************************************/
176 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
177 * frame format) a data length code (can_dlc) which can be from 0 to 8
178 * and up to <can_dlc> data bytes as payload.
179 * Additionally a CAN frame may become a remote transmission frame if the
180 * RTR-bit is set. This causes another ECU to send a CAN frame with the
183 * The SLCAN ASCII representation of these different frame types is:
184 * <type> <id> <dlc> <data>*
186 * Extended frames (29 bit) are defined by capital characters in the type.
187 * RTR frames are defined as 'r' types - normal frames have 't' type:
188 * t => 11 bit data frame
189 * r => 11 bit RTR frame
190 * T => 29 bit data frame
191 * R => 29 bit RTR frame
193 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
194 * The <dlc> is a one byte ASCII number ('0' - '8')
195 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
199 * t1230 : can_id 0x123, can_dlc 0, no data
200 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
201 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
202 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
206 /************************************************************************
207 * STANDARD SLCAN DECAPSULATION *
208 ************************************************************************/
210 static int asc2nibble(char c)
213 if ((c >= '0') && (c <= '9'))
216 if ((c >= 'A') && (c <= 'F'))
219 if ((c >= 'a') && (c <= 'f'))
222 return 16; /* error */
225 /* Send one completely decapsulated can_frame to the network layer */
226 static void slc_bump(struct slcan *sl)
228 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
229 struct net_device_stats *stats = slc_get_stats(sl->dev);
231 struct net_device_stats *stats = &sl->dev->stats;
237 char cmd = sl->rbuff[0];
239 if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
242 if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
243 dlc_pos = 4; /* dlc position tiiid */
245 dlc_pos = 9; /* dlc position Tiiiiiiiid */
247 if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
250 cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
252 sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
254 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
255 ultmp = simple_strtoul(sl->rbuff+1, NULL, 16);
257 if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
262 if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
263 cf.can_id |= CAN_EFF_FLAG;
265 if ((cmd | 0x20) == 'r') /* RTR frame */
266 cf.can_id |= CAN_RTR_FLAG;
268 *(u64 *) (&cf.data) = 0; /* clear payload */
270 for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
272 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
275 cf.data[i] = (tmp << 4);
276 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
283 skb = dev_alloc_skb(sizeof(struct can_frame));
288 skb->protocol = htons(ETH_P_CAN);
289 skb->pkt_type = PACKET_BROADCAST;
290 skb->ip_summed = CHECKSUM_UNNECESSARY;
291 memcpy(skb_put(skb, sizeof(struct can_frame)),
292 &cf, sizeof(struct can_frame));
295 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
296 sl->dev->last_rx = jiffies;
299 stats->rx_bytes += cf.can_dlc;
302 /* parse tty input stream */
303 static void slcan_unesc(struct slcan *sl, unsigned char s)
305 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
306 struct net_device_stats *stats = slc_get_stats(sl->dev);
308 struct net_device_stats *stats = &sl->dev->stats;
311 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
312 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
318 if (!test_bit(SLF_ERROR, &sl->flags)) {
319 if (sl->rcount < SLC_MTU) {
320 sl->rbuff[sl->rcount++] = s;
323 stats->rx_over_errors++;
324 set_bit(SLF_ERROR, &sl->flags);
330 /************************************************************************
331 * STANDARD SLCAN ENCAPSULATION *
332 ************************************************************************/
334 /* Encapsulate one can_frame and stuff into a TTY queue. */
335 static void slc_encaps(struct slcan *sl, struct can_frame *cf)
337 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
338 struct net_device_stats *stats = slc_get_stats(sl->dev);
340 struct net_device_stats *stats = &sl->dev->stats;
345 if (cf->can_id & CAN_RTR_FLAG)
346 cmd = 'R'; /* becomes 'r' in standard frame format */
348 cmd = 'T'; /* becomes 't' in standard frame format */
350 if (cf->can_id & CAN_EFF_FLAG)
351 sprintf(sl->xbuff, "%c%08X%d", cmd,
352 cf->can_id & CAN_EFF_MASK, cf->can_dlc);
354 sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20,
355 cf->can_id & CAN_SFF_MASK, cf->can_dlc);
357 idx = strlen(sl->xbuff);
359 for (i = 0; i < cf->can_dlc; i++)
360 sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
362 strcat(sl->xbuff, "\r"); /* add terminating character */
364 /* Order of next two lines is *very* important.
365 * When we are sending a little amount of data,
366 * the transfer may be completed inside the ops->write()
367 * routine, because it's running with interrupts enabled.
368 * In this case we *never* got WRITE_WAKEUP event,
369 * if we did not request it before write operation.
370 * 14 Oct 1994 Dmitry Gorodchanin.
372 set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
373 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
374 actual = sl->tty->driver->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
376 actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
378 sl->xleft = strlen(sl->xbuff) - actual;
379 sl->xhead = sl->xbuff + actual;
380 stats->tx_bytes += cf->can_dlc;
384 * Called by the driver when there's room for more data. If we have
385 * more packets to send, we send them here.
387 static void slcan_write_wakeup(struct tty_struct *tty)
390 struct slcan *sl = (struct slcan *) tty->disc_data;
391 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
392 struct net_device_stats *stats = slc_get_stats(sl->dev);
394 struct net_device_stats *stats = &sl->dev->stats;
397 /* First make sure we're connected. */
398 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
401 if (sl->xleft <= 0) {
402 /* Now serial buffer is almost free & we can start
403 * transmission of another packet */
405 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
406 netif_wake_queue(sl->dev);
410 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
411 actual = tty->driver->write(tty, sl->xhead, sl->xleft);
413 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
419 /* Send a can_frame to a TTY queue. */
420 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
421 static int slc_xmit(struct sk_buff *skb, struct net_device *dev)
423 static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
426 struct slcan *sl = netdev_priv(dev);
428 if (skb->len != sizeof(struct can_frame))
431 spin_lock(&sl->lock);
432 if (!netif_running(dev)) {
433 spin_unlock(&sl->lock);
434 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
437 if (sl->tty == NULL) {
438 spin_unlock(&sl->lock);
442 netif_stop_queue(sl->dev);
443 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
444 spin_unlock(&sl->lock);
448 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
456 /******************************************
457 * Routines looking at netdevice side.
458 ******************************************/
460 /* Netdevice UP -> DOWN routine */
461 static int slc_close(struct net_device *dev)
463 struct slcan *sl = netdev_priv(dev);
465 spin_lock_bh(&sl->lock);
467 /* TTY discipline is running. */
468 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
470 netif_stop_queue(dev);
473 spin_unlock_bh(&sl->lock);
478 /* Netdevice DOWN -> UP routine */
479 static int slc_open(struct net_device *dev)
481 struct slcan *sl = netdev_priv(dev);
486 sl->flags &= (1 << SLF_INUSE);
487 netif_start_queue(dev);
491 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
492 /* Hook the destructor so we can free slcan devs at the right point in time */
493 static void slc_free_netdev(struct net_device *dev)
495 int i = dev->base_addr;
497 slcan_devs[i] = NULL;
501 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
502 static const struct net_device_ops slc_netdev_ops = {
503 .ndo_open = slc_open,
504 .ndo_stop = slc_close,
505 .ndo_start_xmit = slc_xmit,
509 static void slc_setup(struct net_device *dev)
511 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
512 dev->netdev_ops = &slc_netdev_ops;
514 dev->open = slc_open;
515 dev->stop = slc_close;
516 dev->hard_start_xmit = slc_xmit;
518 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
519 dev->destructor = slc_free_netdev;
521 dev->destructor = free_netdev;
523 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
524 dev->get_stats = slc_get_stats;
527 dev->hard_header_len = 0;
529 dev->tx_queue_len = 10;
531 dev->mtu = sizeof(struct can_frame);
532 dev->type = ARPHRD_CAN;
534 /* New-style flags. */
535 dev->flags = IFF_NOARP;
536 dev->features = NETIF_F_NO_CSUM;
539 /******************************************
540 Routines looking at TTY side.
541 ******************************************/
543 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
544 static int slcan_receive_room(struct tty_struct *tty)
546 return 65536; /* We can handle an infinite amount of data. :-) */
551 * Handle the 'receiver data ready' interrupt.
552 * This function is called by the 'tty_io' module in the kernel when
553 * a block of SLCAN data has been received, which can now be decapsulated
554 * and sent on to some IP layer for further processing. This will not
555 * be re-entered while running but other ldisc functions may be called
559 static void slcan_receive_buf(struct tty_struct *tty,
560 const unsigned char *cp, char *fp, int count)
562 struct slcan *sl = (struct slcan *) tty->disc_data;
563 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
564 struct net_device_stats *stats = slc_get_stats(sl->dev);
566 struct net_device_stats *stats = &sl->dev->stats;
569 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
572 /* Read the characters out of the buffer */
575 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
580 slcan_unesc(sl, *cp++);
584 /************************************
585 * slcan_open helper routines.
586 ************************************/
588 /* Collect hanged up channels */
589 static void slc_sync(void)
592 struct net_device *dev;
595 for (i = 0; i < maxdev; i++) {
600 sl = netdev_priv(dev);
601 if (sl->tty || sl->leased)
603 if (dev->flags & IFF_UP)
608 /* Find a free SLCAN channel, and link in this `tty' line. */
609 static struct slcan *slc_alloc(dev_t line)
614 struct net_device *dev = NULL;
617 if (slcan_devs == NULL)
618 return NULL; /* Master array missing ! */
620 for (i = 0; i < maxdev; i++) {
625 sl = netdev_priv(dev);
627 if (sl->line != line)
632 /* Clear ESCAPE & ERROR flags */
633 sl->flags &= (1 << SLF_INUSE);
640 if (current->pid == sl->pid) {
641 if (sl->line == line && score < 3) {
652 if (sl->line == line && score < 1) {
667 sl = netdev_priv(dev);
668 sl->flags &= (1 << SLF_INUSE);
673 /* Sorry, too many, all slots in use */
678 sl = netdev_priv(dev);
679 if (test_bit(SLF_INUSE, &sl->flags)) {
680 unregister_netdevice(dev);
682 slcan_devs[i] = NULL;
688 sprintf(name, "slcan%d", i);
690 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
696 sl = netdev_priv(dev);
698 /* Initialize channel control data */
699 sl->magic = SLCAN_MAGIC;
701 spin_lock_init(&sl->lock);
708 * Open the high-level part of the SLCAN channel.
709 * This function is called by the TTY module when the
710 * SLCAN line discipline is called for. Because we are
711 * sure the tty line exists, we only have to link it to
712 * a free SLCAN channel...
714 * Called in process context serialized from other ldisc calls.
717 static int slcan_open(struct tty_struct *tty)
722 if (!capable(CAP_NET_ADMIN))
725 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,25)
726 if (tty->ops->write == NULL)
730 /* RTnetlink lock is misused here to serialize concurrent
731 opens of slcan channels. There are better ways, but it is
736 /* Collect hanged up channels. */
742 /* First make sure we're not already connected. */
743 if (sl && sl->magic == SLCAN_MAGIC)
746 /* OK. Find a free SLCAN channel to use. */
748 sl = slc_alloc(tty_devnum(tty));
754 sl->line = tty_devnum(tty);
755 sl->pid = current->pid;
757 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
758 /* FIXME: already done before we were called - seems this can go */
759 if (tty->driver->flush_buffer)
760 tty->driver->flush_buffer(tty);
763 if (!test_bit(SLF_INUSE, &sl->flags)) {
764 /* Perform the low-level SLCAN initialization. */
768 set_bit(SLF_INUSE, &sl->flags);
770 err = register_netdevice(sl->dev);
775 /* Done. We have linked the TTY line to a channel. */
777 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
778 tty->receive_room = 65536; /* We don't flow control */
780 return sl->dev->base_addr;
784 tty->disc_data = NULL;
785 clear_bit(SLF_INUSE, &sl->flags);
790 /* Count references from TTY module */
795 * Close down a SLCAN channel.
796 * This means flushing out any pending queues, and then returning. This
797 * call is serialized against other ldisc functions.
799 * We also use this method for a hangup event.
802 static void slcan_close(struct tty_struct *tty)
804 struct slcan *sl = (struct slcan *) tty->disc_data;
806 /* First make sure we're connected. */
807 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
810 tty->disc_data = NULL;
815 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
816 /* Flush network side */
817 unregister_netdev(sl->dev);
818 /* This will complete via sl_free_netdev */
820 /* Count references from TTY module */
824 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
825 static int slcan_hangup(struct tty_struct *tty)
832 /* Perform I/O control on an active SLCAN channel. */
833 static int slcan_ioctl(struct tty_struct *tty, struct file *file,
834 unsigned int cmd, unsigned long arg)
836 struct slcan *sl = (struct slcan *) tty->disc_data;
839 /* First make sure we're connected. */
840 if (!sl || sl->magic != SLCAN_MAGIC)
845 tmp = strlen(sl->dev->name) + 1;
846 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
853 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
854 /* Allow stty to read, but not set, the serial port */
857 return n_tty_ioctl(tty, file, cmd, arg);
863 return tty_mode_ioctl(tty, file, cmd, arg);
868 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
869 static struct tty_ldisc slc_ldisc = {
871 static struct tty_ldisc_ops slc_ldisc = {
873 .owner = THIS_MODULE,
874 .magic = TTY_LDISC_MAGIC,
877 .close = slcan_close,
878 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
879 .hangup = slcan_hangup,
881 .ioctl = slcan_ioctl,
882 .receive_buf = slcan_receive_buf,
883 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
884 .receive_room = slcan_receive_room,
886 .write_wakeup = slcan_write_wakeup,
889 static int __init slcan_init(void)
894 maxdev = 4; /* Sanity */
897 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
899 slcan_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
901 printk(KERN_ERR "slcan: can't allocate slcan device array!\n");
905 /* Fill in our line protocol discipline, and register it */
906 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
908 printk(KERN_ERR "slcan: can't register line discipline\n");
914 static void __exit slcan_exit(void)
917 struct net_device *dev;
919 unsigned long timeout = jiffies + HZ;
922 if (slcan_devs == NULL)
925 /* First of all: check for active disciplines and hangup them.
929 msleep_interruptible(100);
932 for (i = 0; i < maxdev; i++) {
936 sl = netdev_priv(dev);
937 spin_lock_bh(&sl->lock);
942 spin_unlock_bh(&sl->lock);
944 } while (busy && time_before(jiffies, timeout));
946 /* FIXME: hangup is async so we should wait when doing this second
949 for (i = 0; i < maxdev; i++) {
953 slcan_devs[i] = NULL;
955 sl = netdev_priv(dev);
957 printk(KERN_ERR "%s: tty discipline still running\n",
959 /* Intentionally leak the control block. */
960 dev->destructor = NULL;
963 unregister_netdev(dev);
969 i = tty_unregister_ldisc(N_SLCAN);
971 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
974 module_init(slcan_init);
975 module_exit(slcan_exit);