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>
70 #include <socketcan/can.h>
72 #include <socketcan/can/version.h> /* for RCSID. Removed by mkpatch script */
75 static __initdata const char banner[] =
76 KERN_INFO "slcan: serial line CAN interface driver\n";
78 MODULE_ALIAS_LDISC(N_SLCAN);
79 MODULE_DESCRIPTION("serial line CAN interface");
80 MODULE_LICENSE("GPL");
81 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
83 #ifdef CONFIG_CAN_DEBUG_DEVICES
85 module_param(debug, int, S_IRUGO);
86 #define DBG(args...) (debug & 1 ? \
87 (printk(KERN_DEBUG "slcan %s: ", __func__), \
94 #error Your kernel does not support tty line discipline N_SLCAN
97 * As there is currently no line discipline N_SLCAN in the mainstream kernel
98 * you will have to modify two kernel includes & recompile the kernel.
100 * Add this in include/asm/termios.h after the definition of N_HCI:
103 * Increment NR_LDICS in include/linux/tty.h from 16 to 17
105 * NEW: Since Kernel 2.6.21 you only have to change include/linux/tty.h
107 * HACK for precompiled Kernels:
109 * In order to use the slcan driver without rebuilding the kernel, the slcan
110 * driver must be compiled to use an existing line discipline.
111 * The N_MOUSE line discipline is documented to be free for custom use and
112 * using it *should* not cause any side effect.
114 * Then, before compiling the slcan driver, add a -DN_SLCAN=N_MOUSE
115 * compilation option in its Makefile. The slcan_attach tool must(!!) also be
116 * rebuild to use the right value for N_SLCAN. This workaround will allow
117 * to use the slcan driver with an existing kernel.
120 #define SLCAN_MAGIC 0x53CA
122 static int maxdev = 10; /* MAX number of SLCAN channels;
123 This can be overridden with
124 insmod slcan.ko maxdev=nnn */
125 module_param(maxdev, int, 0);
126 MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
128 /* maximum rx buffer len: extended CAN frame with timestamp */
129 #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
134 /* Various fields. */
135 struct tty_struct *tty; /* ptr to TTY structure */
136 struct net_device *dev; /* easy for intr handling */
139 /* These are pointers to the malloc()ed frame buffers. */
140 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
141 int rcount; /* received chars counter */
142 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
143 unsigned char *xhead; /* pointer to next XMIT byte */
144 int xleft; /* bytes left in XMIT queue */
146 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
147 /* SLCAN interface statistics. */
148 struct net_device_stats stats;
151 unsigned long flags; /* Flag values/ mode etc */
152 #define SLF_INUSE 0 /* Channel in use */
153 #define SLF_ERROR 1 /* Parity, etc. error */
155 unsigned char leased;
160 static struct net_device **slcan_devs;
163 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
164 /* Netdevice get statistics request */
165 static struct net_device_stats *slc_get_stats(struct net_device *dev)
167 struct slcan *sl = netdev_priv(dev);
173 /************************************************************************
174 * SLCAN ENCAPSULATION FORMAT *
175 ************************************************************************/
178 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
179 * frame format) a data length code (can_dlc) which can be from 0 to 8
180 * and up to <can_dlc> data bytes as payload.
181 * Additionally a CAN frame may become a remote transmission frame if the
182 * RTR-bit is set. This causes another ECU to send a CAN frame with the
185 * The SLCAN ASCII representation of these different frame types is:
186 * <type> <id> <dlc> <data>*
188 * Extended frames (29 bit) are defined by capital characters in the type.
189 * RTR frames are defined as 'r' types - normal frames have 't' type:
190 * t => 11 bit data frame
191 * r => 11 bit RTR frame
192 * T => 29 bit data frame
193 * R => 29 bit RTR frame
195 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
196 * The <dlc> is a one byte ASCII number ('0' - '8')
197 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
201 * t1230 : can_id 0x123, can_dlc 0, no data
202 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
203 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
204 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
208 /************************************************************************
209 * STANDARD SLCAN DECAPSULATION *
210 ************************************************************************/
212 static int asc2nibble(char c)
215 if ((c >= '0') && (c <= '9'))
218 if ((c >= 'A') && (c <= 'F'))
221 if ((c >= 'a') && (c <= 'f'))
224 return 16; /* error */
227 /* Send one completely decapsulated can_frame to the network layer */
228 static void slc_bump(struct slcan *sl)
230 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
231 struct net_device_stats *stats = slc_get_stats(sl->dev);
233 struct net_device_stats *stats = &sl->dev->stats;
239 char cmd = sl->rbuff[0];
241 if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
244 if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
245 dlc_pos = 4; /* dlc position tiiid */
247 dlc_pos = 9; /* dlc position Tiiiiiiiid */
249 if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
252 cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
254 sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
256 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
257 ultmp = simple_strtoul(sl->rbuff+1, NULL, 16);
259 if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
264 if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
265 cf.can_id |= CAN_EFF_FLAG;
267 if ((cmd | 0x20) == 'r') /* RTR frame */
268 cf.can_id |= CAN_RTR_FLAG;
270 *(u64 *) (&cf.data) = 0; /* clear payload */
272 for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
274 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
277 cf.data[i] = (tmp << 4);
278 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
285 skb = dev_alloc_skb(sizeof(struct can_frame));
290 skb->protocol = htons(ETH_P_CAN);
291 skb->pkt_type = PACKET_BROADCAST;
292 skb->ip_summed = CHECKSUM_UNNECESSARY;
293 memcpy(skb_put(skb, sizeof(struct can_frame)),
294 &cf, sizeof(struct can_frame));
297 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
298 sl->dev->last_rx = jiffies;
301 stats->rx_bytes += cf.can_dlc;
304 /* parse tty input stream */
305 static void slcan_unesc(struct slcan *sl, unsigned char s)
307 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
308 struct net_device_stats *stats = slc_get_stats(sl->dev);
310 struct net_device_stats *stats = &sl->dev->stats;
313 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
314 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
320 if (!test_bit(SLF_ERROR, &sl->flags)) {
321 if (sl->rcount < SLC_MTU) {
322 sl->rbuff[sl->rcount++] = s;
325 stats->rx_over_errors++;
326 set_bit(SLF_ERROR, &sl->flags);
332 /************************************************************************
333 * STANDARD SLCAN ENCAPSULATION *
334 ************************************************************************/
336 /* Encapsulate one can_frame and stuff into a TTY queue. */
337 static void slc_encaps(struct slcan *sl, struct can_frame *cf)
339 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
340 struct net_device_stats *stats = slc_get_stats(sl->dev);
342 struct net_device_stats *stats = &sl->dev->stats;
347 if (cf->can_id & CAN_RTR_FLAG)
348 cmd = 'R'; /* becomes 'r' in standard frame format */
350 cmd = 'T'; /* becomes 't' in standard frame format */
352 if (cf->can_id & CAN_EFF_FLAG)
353 sprintf(sl->xbuff, "%c%08X%d", cmd,
354 cf->can_id & CAN_EFF_MASK, cf->can_dlc);
356 sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20,
357 cf->can_id & CAN_SFF_MASK, cf->can_dlc);
359 idx = strlen(sl->xbuff);
361 for (i = 0; i < cf->can_dlc; i++)
362 sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
364 DBG("ASCII frame = '%s'\n", sl->xbuff);
366 strcat(sl->xbuff, "\r"); /* add terminating character */
368 /* Order of next two lines is *very* important.
369 * When we are sending a little amount of data,
370 * the transfer may be completed inside driver.write()
371 * routine, because it's running with interrupts enabled.
372 * In this case we *never* got WRITE_WAKEUP event,
373 * if we did not request it before write operation.
374 * 14 Oct 1994 Dmitry Gorodchanin.
376 sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
377 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
378 actual = sl->tty->driver->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
380 actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
382 sl->xleft = strlen(sl->xbuff) - actual;
383 sl->xhead = sl->xbuff + actual;
384 stats->tx_bytes += cf->can_dlc;
388 * Called by the driver when there's room for more data. If we have
389 * more packets to send, we send them here.
391 static void slcan_write_wakeup(struct tty_struct *tty)
394 struct slcan *sl = (struct slcan *) tty->disc_data;
395 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
396 struct net_device_stats *stats = slc_get_stats(sl->dev);
398 struct net_device_stats *stats = &sl->dev->stats;
401 /* First make sure we're connected. */
402 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
405 if (sl->xleft <= 0) {
406 /* Now serial buffer is almost free & we can start
407 * transmission of another packet */
409 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
410 netif_wake_queue(sl->dev);
414 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
415 actual = tty->driver->write(tty, sl->xhead, sl->xleft);
417 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
424 /******************************************
425 * Routines looking at netdevice side.
426 ******************************************/
428 /* Send a can_frame to a TTY queue. */
429 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
430 static int slc_xmit(struct sk_buff *skb, struct net_device *dev)
432 static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
435 struct slcan *sl = netdev_priv(dev);
437 if (skb->len != sizeof(struct can_frame))
440 spin_lock(&sl->lock);
441 if (!netif_running(dev)) {
442 spin_unlock(&sl->lock);
443 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
447 if (sl->tty == NULL) {
448 spin_unlock(&sl->lock);
452 netif_stop_queue(sl->dev);
453 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
454 spin_unlock(&sl->lock);
458 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
466 /* Netdevice UP -> DOWN routine */
467 static int slc_close(struct net_device *dev)
469 struct slcan *sl = netdev_priv(dev);
471 spin_lock_bh(&sl->lock);
473 /* TTY discipline is running. */
474 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
476 netif_stop_queue(dev);
479 spin_unlock_bh(&sl->lock);
484 /* Netdevice DOWN -> UP routine */
485 static int slc_open(struct net_device *dev)
487 struct slcan *sl = netdev_priv(dev);
492 sl->flags &= (1 << SLF_INUSE);
493 netif_start_queue(dev);
497 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
498 /* Hook the destructor so we can free slcan devs at the right point in time */
499 static void slc_free_netdev(struct net_device *dev)
501 int i = dev->base_addr;
503 slcan_devs[i] = NULL;
507 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
508 static const struct net_device_ops slc_netdev_ops = {
509 .ndo_open = slc_open,
510 .ndo_stop = slc_close,
511 .ndo_start_xmit = slc_xmit,
515 /* Netdevice register callback */
516 static void slc_setup(struct net_device *dev)
518 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
519 dev->netdev_ops = &slc_netdev_ops;
521 dev->open = slc_open;
522 dev->stop = slc_close;
523 dev->hard_start_xmit = slc_xmit;
525 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
526 dev->destructor = slc_free_netdev;
528 dev->destructor = free_netdev;
530 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
531 dev->get_stats = slc_get_stats;
534 dev->hard_header_len = 0;
536 dev->tx_queue_len = 10;
538 dev->mtu = sizeof(struct can_frame);
539 dev->type = ARPHRD_CAN;
541 /* New-style flags. */
542 dev->flags = IFF_NOARP;
543 dev->features = NETIF_F_NO_CSUM;
546 /******************************************
547 * Routines looking at TTY side.
548 ******************************************/
550 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
551 static int slcan_receive_room(struct tty_struct *tty)
553 return 65536; /* We can handle an infinite amount of data. :-) */
558 * Handle the 'receiver data ready' interrupt.
559 * This function is called by the 'tty_io' module in the kernel when
560 * a block of SLCAN data has been received, which can now be decapsulated
561 * and sent on to some IP layer for further processing. This will not
562 * be re-entered while running but other ldisc functions may be called
566 static void slcan_receive_buf(struct tty_struct *tty,
567 const unsigned char *cp, char *fp, int count)
569 struct slcan *sl = (struct slcan *) tty->disc_data;
570 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
571 struct net_device_stats *stats = slc_get_stats(sl->dev);
573 struct net_device_stats *stats = &sl->dev->stats;
576 if (!sl || sl->magic != SLCAN_MAGIC ||
577 !netif_running(sl->dev))
580 /* Read the characters out of the buffer */
583 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
588 slcan_unesc(sl, *cp++);
592 /************************************
593 * slcan_open helper routines.
594 ************************************/
596 /* Collect hanged up channels */
598 static void slc_sync(void)
601 struct net_device *dev;
604 for (i = 0; i < maxdev; i++) {
609 sl = netdev_priv(dev);
610 if (sl->tty || sl->leased)
612 if (dev->flags&IFF_UP)
618 /* Find a free SLCAN channel, and link in this `tty' line. */
619 static struct slcan *slc_alloc(dev_t line)
624 struct net_device *dev = NULL;
627 if (slcan_devs == NULL)
628 return NULL; /* Master array missing ! */
630 for (i = 0; i < maxdev; i++) {
635 sl = netdev_priv(dev);
637 if (sl->line != line)
642 /* Clear ESCAPE & ERROR flags */
643 sl->flags &= (1 << SLF_INUSE);
650 if (current->pid == sl->pid) {
651 if (sl->line == line && score < 3) {
662 if (sl->line == line && score < 1) {
677 sl = netdev_priv(dev);
678 sl->flags &= (1 << SLF_INUSE);
683 /* Sorry, too many, all slots in use */
688 sl = netdev_priv(dev);
689 if (test_bit(SLF_INUSE, &sl->flags)) {
690 unregister_netdevice(dev);
692 slcan_devs[i] = NULL;
698 sprintf(name, "slcan%d", i);
700 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
706 sl = netdev_priv(dev);
708 /* Initialize channel control data */
709 sl->magic = SLCAN_MAGIC;
711 spin_lock_init(&sl->lock);
718 * Open the high-level part of the SLCAN channel.
719 * This function is called by the TTY module when the
720 * SLCAN line discipline is called for. Because we are
721 * sure the tty line exists, we only have to link it to
722 * a free SLCAN channel...
724 * Called in process context serialized from other ldisc calls.
727 static int slcan_open(struct tty_struct *tty)
732 if (!capable(CAP_NET_ADMIN))
735 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,25)
736 if (tty->ops->write == NULL)
740 /* RTnetlink lock is misused here to serialize concurrent
741 opens of slcan channels. There are better ways, but it is
746 /* Collect hanged up channels. */
749 sl = (struct slcan *) tty->disc_data;
752 /* First make sure we're not already connected. */
753 if (sl && sl->magic == SLCAN_MAGIC)
756 /* OK. Find a free SLCAN channel to use. */
758 sl = slc_alloc(tty_devnum(tty));
764 sl->line = tty_devnum(tty);
765 sl->pid = current->pid;
767 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
768 /* FIXME: already done before we were called - seems this can go */
769 if (tty->driver->flush_buffer)
770 tty->driver->flush_buffer(tty);
773 if (!test_bit(SLF_INUSE, &sl->flags)) {
774 /* Perform the low-level SLCAN initialization. */
778 set_bit(SLF_INUSE, &sl->flags);
780 err = register_netdevice(sl->dev);
785 /* Done. We have linked the TTY line to a channel. */
788 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
789 tty->receive_room = 65536; /* We don't flow control */
792 return sl->dev->base_addr;
796 tty->disc_data = NULL;
797 clear_bit(SLF_INUSE, &sl->flags);
802 /* Count references from TTY module */
807 * Close down a SLCAN channel.
808 * This means flushing out any pending queues, and then returning. This
809 * call is serialized against other ldisc functions.
811 * We also use this method for a hangup event.
813 static void slcan_close(struct tty_struct *tty)
815 struct slcan *sl = (struct slcan *) tty->disc_data;
817 /* First make sure we're connected. */
818 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
821 tty->disc_data = NULL;
826 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
827 /* Flush network side */
828 unregister_netdev(sl->dev);
829 /* This will complete via sl_free_netdev */
831 /* Count references from TTY module */
835 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
836 static int slcan_hangup(struct tty_struct *tty)
843 /* Perform I/O control on an active SLCAN channel. */
844 static int slcan_ioctl(struct tty_struct *tty, struct file *file,
845 unsigned int cmd, unsigned long arg)
847 struct slcan *sl = (struct slcan *) tty->disc_data;
850 /* First make sure we're connected. */
851 if (!sl || sl->magic != SLCAN_MAGIC)
856 tmp = strlen(sl->dev->name) + 1;
857 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
864 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
865 /* Allow stty to read, but not set, the serial port */
868 return n_tty_ioctl(tty, file, cmd, arg);
874 return tty_mode_ioctl(tty, file, cmd, arg);
879 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
880 static struct tty_ldisc slc_ldisc = {
882 static struct tty_ldisc_ops slc_ldisc = {
884 .owner = THIS_MODULE,
885 .magic = TTY_LDISC_MAGIC,
888 .close = slcan_close,
889 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
890 .hangup = slcan_hangup,
892 .ioctl = slcan_ioctl,
893 .receive_buf = slcan_receive_buf,
894 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
895 .receive_room = slcan_receive_room,
897 .write_wakeup = slcan_write_wakeup,
900 /************************************
901 * general slcan module init/exit
902 ************************************/
904 static int __init slcan_init(void)
909 maxdev = 4; /* Sanity */
912 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
914 slcan_devs = kmalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
916 printk(KERN_ERR "slcan: can't allocate slcan device array!\n");
920 /* Clear the pointer array, we allocate devices when we need them */
921 memset(slcan_devs, 0, sizeof(struct net_device *)*maxdev);
923 /* Fill in our line protocol discipline, and register it */
924 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
926 printk(KERN_ERR "slcan: can't register line discipline\n");
932 static void __exit slcan_exit(void)
935 struct net_device *dev;
937 unsigned long timeout = jiffies + HZ;
940 if (slcan_devs == NULL)
943 /* First of all: check for active disciplines and hangup them.
947 msleep_interruptible(100);
950 for (i = 0; i < maxdev; i++) {
954 sl = netdev_priv(dev);
955 spin_lock_bh(&sl->lock);
960 spin_unlock_bh(&sl->lock);
962 } while (busy && time_before(jiffies, timeout));
964 /* FIXME (2.6.32+): hangup is async so we should wait when doing
967 for (i = 0; i < maxdev; i++) {
971 slcan_devs[i] = NULL;
973 sl = netdev_priv(dev);
975 printk(KERN_ERR "%s: tty discipline still running\n",
977 /* Intentionally leak the control block. */
978 dev->destructor = NULL;
981 unregister_netdev(dev);
987 i = tty_unregister_ldisc(N_SLCAN);
989 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
992 module_init(slcan_init);
993 module_exit(slcan_exit);