2 * slcan.c - serial line CAN interface driver (using tty line discipline)
4 * This file is derived from linux/drivers/net/slip.c
6 * Therefore it has the same (strange?) behaviour not to unregister the
7 * netdevice when detaching the tty. Is there any better solution?
9 * Do not try to attach, detach and re-attach a tty for this reason ...
11 * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
12 * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
13 * slcan.c Author : Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
15 * Copyright (c) 2007-2009 Volkswagen Group Electronic Research
17 * This program is free software; you can redistribute it and/or modify it
18 * under the terms of the GNU General Public License as published by the
19 * Free Software Foundation; either version 2 of the License, or (at your
20 * option) any later version.
22 * This program is distributed in the hope that it will be useful, but
23 * WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25 * General Public License for more details.
27 * You should have received a copy of the GNU General Public License along
28 * with this program; if not, write to the Free Software Foundation, Inc.,
29 * 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it
30 * at http://www.gnu.org/licenses/gpl.html
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
35 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
37 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
38 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
39 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
40 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
41 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
42 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
45 * Send feedback to <socketcan-users@lists.berlios.de>
49 #include <linux/version.h>
50 #include <linux/module.h>
51 #include <linux/moduleparam.h>
53 #include <asm/system.h>
54 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17)
55 #include <linux/uaccess.h>
57 #include <asm/uaccess.h>
59 #include <linux/bitops.h>
60 #include <linux/sched.h>
61 #include <linux/string.h>
63 #include <linux/interrupt.h>
65 #include <linux/tty.h>
66 #include <linux/errno.h>
67 #include <linux/netdevice.h>
68 #include <linux/etherdevice.h>
69 #include <linux/skbuff.h>
70 #include <linux/rtnetlink.h>
71 #include <linux/if_arp.h>
72 #include <linux/if_ether.h>
73 #include <linux/if_slip.h>
74 #include <linux/delay.h>
75 #include <linux/init.h>
77 #include <socketcan/can.h>
79 #include <socketcan/can/version.h> /* for RCSID. Removed by mkpatch script */
82 static __initdata const char banner[] =
83 KERN_INFO "slcan: serial line CAN interface driver\n";
85 MODULE_ALIAS_LDISC(N_SLCAN);
86 MODULE_DESCRIPTION("serial line CAN interface");
87 MODULE_LICENSE("GPL");
88 MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
90 #ifdef CONFIG_CAN_DEBUG_DEVICES
92 module_param(debug, int, S_IRUGO);
93 #define DBG(args...) (debug & 1 ? \
94 (printk(KERN_DEBUG "slcan %s: ", __func__), \
101 #error Your kernel does not support tty line discipline N_SLCAN
104 * As there is currently no line discipline N_SLCAN in the mainstream kernel
105 * you will have to modify two kernel includes & recompile the kernel.
107 * Add this in include/asm/termios.h after the definition of N_HCI:
110 * Increment NR_LDICS in include/linux/tty.h from 16 to 17
112 * NEW: Since Kernel 2.6.21 you only have to change include/linux/tty.h
114 * HACK for precompiled Kernels:
116 * In order to use the slcan driver without rebuilding the kernel, the slcan
117 * driver must be compiled to use an existing line discipline.
118 * The N_MOUSE line discipline is documented to be free for custom use and
119 * using it *should* not cause any side effect.
121 * Then, before compiling the slcan driver, add a -DN_SLCAN=N_MOUSE
122 * compilation option in its Makefile. The slcan_attach tool must(!!) also be
123 * rebuild to use the right value for N_SLCAN. This workaround will allow
124 * to use the slcan driver with an existing kernel.
127 #define SLCAN_MAGIC 0x53CA
129 static int maxdev = 10; /* MAX number of SLCAN channels;
130 This can be overridden with
131 insmod slcan.ko maxdev=nnn */
132 module_param(maxdev, int, 0);
133 MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
135 /* maximum rx buffer len: extended CAN frame with timestamp */
136 #define SLC_MTU (sizeof("T1111222281122334455667788EA5F\r")+1)
141 /* Various fields. */
142 struct tty_struct *tty; /* ptr to TTY structure */
143 struct net_device *dev; /* easy for intr handling */
146 /* These are pointers to the malloc()ed frame buffers. */
147 unsigned char rbuff[SLC_MTU]; /* receiver buffer */
148 int rcount; /* received chars counter */
149 unsigned char xbuff[SLC_MTU]; /* transmitter buffer */
150 unsigned char *xhead; /* pointer to next XMIT byte */
151 int xleft; /* bytes left in XMIT queue */
153 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
154 /* SLCAN interface statistics. */
155 struct net_device_stats stats;
158 unsigned long flags; /* Flag values/ mode etc */
159 #define SLF_INUSE 0 /* Channel in use */
160 #define SLF_ERROR 1 /* Parity, etc. error */
162 unsigned char leased;
167 static struct net_device **slcan_devs;
170 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
171 /* Netdevice get statistics request */
172 static struct net_device_stats *slc_get_stats(struct net_device *dev)
174 struct slcan *sl = netdev_priv(dev);
180 /************************************************************************
181 * SLCAN ENCAPSULATION FORMAT *
182 ************************************************************************/
185 * A CAN frame has a can_id (11 bit standard frame format OR 29 bit extended
186 * frame format) a data length code (can_dlc) which can be from 0 to 8
187 * and up to <can_dlc> data bytes as payload.
188 * Additionally a CAN frame may become a remote transmission frame if the
189 * RTR-bit is set. This causes another ECU to send a CAN frame with the
192 * The SLCAN ASCII representation of these different frame types is:
193 * <type> <id> <dlc> <data>*
195 * Extended frames (29 bit) are defined by capital characters in the type.
196 * RTR frames are defined as 'r' types - normal frames have 't' type:
197 * t => 11 bit data frame
198 * r => 11 bit RTR frame
199 * T => 29 bit data frame
200 * R => 29 bit RTR frame
202 * The <id> is 3 (standard) or 8 (extended) bytes in ASCII Hex (base64).
203 * The <dlc> is a one byte ASCII number ('0' - '8')
204 * The <data> section has at much ASCII Hex bytes as defined by the <dlc>
208 * t1230 : can_id 0x123, can_dlc 0, no data
209 * t4563112233 : can_id 0x456, can_dlc 3, data 0x11 0x22 0x33
210 * T12ABCDEF2AA55 : extended can_id 0x12ABCDEF, can_dlc 2, data 0xAA 0x55
211 * r1230 : can_id 0x123, can_dlc 0, no data, remote transmission request
215 /************************************************************************
216 * STANDARD SLCAN DECAPSULATION *
217 ************************************************************************/
219 static int asc2nibble(char c)
222 if ((c >= '0') && (c <= '9'))
225 if ((c >= 'A') && (c <= 'F'))
228 if ((c >= 'a') && (c <= 'f'))
231 return 16; /* error */
234 /* Send one completely decapsulated can_frame to the network layer */
235 static void slc_bump(struct slcan *sl)
237 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
238 struct net_device_stats *stats = slc_get_stats(sl->dev);
240 struct net_device_stats *stats = &sl->dev->stats;
246 char cmd = sl->rbuff[0];
248 if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
251 if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
252 dlc_pos = 4; /* dlc position tiiid */
254 dlc_pos = 9; /* dlc position Tiiiiiiiid */
256 if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
259 cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
261 sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
263 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,25)
264 ultmp = simple_strtoul(sl->rbuff+1, NULL, 16);
266 if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
271 if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
272 cf.can_id |= CAN_EFF_FLAG;
274 if ((cmd | 0x20) == 'r') /* RTR frame */
275 cf.can_id |= CAN_RTR_FLAG;
277 *(u64 *) (&cf.data) = 0; /* clear payload */
279 for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
281 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
284 cf.data[i] = (tmp << 4);
285 tmp = asc2nibble(sl->rbuff[dlc_pos++]);
292 skb = dev_alloc_skb(sizeof(struct can_frame));
297 skb->protocol = htons(ETH_P_CAN);
298 skb->pkt_type = PACKET_BROADCAST;
299 skb->ip_summed = CHECKSUM_UNNECESSARY;
300 memcpy(skb_put(skb, sizeof(struct can_frame)),
301 &cf, sizeof(struct can_frame));
304 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
305 sl->dev->last_rx = jiffies;
308 stats->rx_bytes += cf.can_dlc;
311 /* parse tty input stream */
312 static void slcan_unesc(struct slcan *sl, unsigned char s)
314 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
315 struct net_device_stats *stats = slc_get_stats(sl->dev);
317 struct net_device_stats *stats = &sl->dev->stats;
320 if ((s == '\r') || (s == '\a')) { /* CR or BEL ends the pdu */
321 if (!test_and_clear_bit(SLF_ERROR, &sl->flags) &&
327 if (!test_bit(SLF_ERROR, &sl->flags)) {
328 if (sl->rcount < SLC_MTU) {
329 sl->rbuff[sl->rcount++] = s;
332 stats->rx_over_errors++;
333 set_bit(SLF_ERROR, &sl->flags);
339 /************************************************************************
340 * STANDARD SLCAN ENCAPSULATION *
341 ************************************************************************/
343 /* Encapsulate one can_frame and stuff into a TTY queue. */
344 static void slc_encaps(struct slcan *sl, struct can_frame *cf)
346 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
347 struct net_device_stats *stats = slc_get_stats(sl->dev);
349 struct net_device_stats *stats = &sl->dev->stats;
354 if (cf->can_id & CAN_RTR_FLAG)
355 cmd = 'R'; /* becomes 'r' in standard frame format */
357 cmd = 'T'; /* becomes 't' in standard frame format */
359 if (cf->can_id & CAN_EFF_FLAG)
360 sprintf(sl->xbuff, "%c%08X%d", cmd,
361 cf->can_id & CAN_EFF_MASK, cf->can_dlc);
363 sprintf(sl->xbuff, "%c%03X%d", cmd | 0x20,
364 cf->can_id & CAN_SFF_MASK, cf->can_dlc);
366 idx = strlen(sl->xbuff);
368 for (i = 0; i < cf->can_dlc; i++)
369 sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
371 DBG("ASCII frame = '%s'\n", sl->xbuff);
373 strcat(sl->xbuff, "\r"); /* add terminating character */
375 /* Order of next two lines is *very* important.
376 * When we are sending a little amount of data,
377 * the transfer may be completed inside driver.write()
378 * routine, because it's running with interrupts enabled.
379 * In this case we *never* got WRITE_WAKEUP event,
380 * if we did not request it before write operation.
381 * 14 Oct 1994 Dmitry Gorodchanin.
383 sl->tty->flags |= (1 << TTY_DO_WRITE_WAKEUP);
384 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
385 actual = sl->tty->driver->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
387 actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
389 sl->xleft = strlen(sl->xbuff) - actual;
390 sl->xhead = sl->xbuff + actual;
391 stats->tx_bytes += cf->can_dlc;
395 * Called by the driver when there's room for more data. If we have
396 * more packets to send, we send them here.
398 static void slcan_write_wakeup(struct tty_struct *tty)
401 struct slcan *sl = (struct slcan *) tty->disc_data;
402 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
403 struct net_device_stats *stats = slc_get_stats(sl->dev);
405 struct net_device_stats *stats = &sl->dev->stats;
408 /* First make sure we're connected. */
409 if (!sl || sl->magic != SLCAN_MAGIC || !netif_running(sl->dev))
412 if (sl->xleft <= 0) {
413 /* Now serial buffer is almost free & we can start
414 * transmission of another packet */
416 tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
417 netif_wake_queue(sl->dev);
421 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
422 actual = tty->driver->write(tty, sl->xhead, sl->xleft);
424 actual = tty->ops->write(tty, sl->xhead, sl->xleft);
431 /******************************************
432 * Routines looking at netdevice side.
433 ******************************************/
435 /* Send a can_frame to a TTY queue. */
436 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
437 static int slc_xmit(struct sk_buff *skb, struct net_device *dev)
439 static netdev_tx_t slc_xmit(struct sk_buff *skb, struct net_device *dev)
442 struct slcan *sl = netdev_priv(dev);
444 if (skb->len != sizeof(struct can_frame))
447 spin_lock(&sl->lock);
448 if (!netif_running(dev)) {
449 spin_unlock(&sl->lock);
450 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
454 if (sl->tty == NULL) {
455 spin_unlock(&sl->lock);
459 netif_stop_queue(sl->dev);
460 slc_encaps(sl, (struct can_frame *) skb->data); /* encaps & send */
461 spin_unlock(&sl->lock);
465 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
473 /* Netdevice UP -> DOWN routine */
474 static int slc_close(struct net_device *dev)
476 struct slcan *sl = netdev_priv(dev);
478 spin_lock_bh(&sl->lock);
480 /* TTY discipline is running. */
481 sl->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
483 netif_stop_queue(dev);
486 spin_unlock_bh(&sl->lock);
491 /* Netdevice DOWN -> UP routine */
492 static int slc_open(struct net_device *dev)
494 struct slcan *sl = netdev_priv(dev);
499 sl->flags &= (1 << SLF_INUSE);
500 netif_start_queue(dev);
504 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
505 /* Hook the destructor so we can free slcan devs at the right point in time */
506 static void slc_free_netdev(struct net_device *dev)
508 int i = dev->base_addr;
510 slcan_devs[i] = NULL;
514 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
515 static const struct net_device_ops slc_netdev_ops = {
516 .ndo_open = slc_open,
517 .ndo_stop = slc_close,
518 .ndo_start_xmit = slc_xmit,
522 /* Netdevice register callback */
523 static void slc_setup(struct net_device *dev)
525 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,28)
526 dev->netdev_ops = &slc_netdev_ops;
528 dev->open = slc_open;
529 dev->stop = slc_close;
530 dev->hard_start_xmit = slc_xmit;
532 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
533 dev->destructor = slc_free_netdev;
535 dev->destructor = free_netdev;
537 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
538 dev->get_stats = slc_get_stats;
541 dev->hard_header_len = 0;
543 dev->tx_queue_len = 10;
545 dev->mtu = sizeof(struct can_frame);
546 dev->type = ARPHRD_CAN;
548 /* New-style flags. */
549 dev->flags = IFF_NOARP;
550 dev->features = NETIF_F_NO_CSUM;
553 /******************************************
554 * Routines looking at TTY side.
555 ******************************************/
557 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
558 static int slcan_receive_room(struct tty_struct *tty)
560 return 65536; /* We can handle an infinite amount of data. :-) */
565 * Handle the 'receiver data ready' interrupt.
566 * This function is called by the 'tty_io' module in the kernel when
567 * a block of SLCAN data has been received, which can now be decapsulated
568 * and sent on to some IP layer for further processing. This will not
569 * be re-entered while running but other ldisc functions may be called
573 static void slcan_receive_buf(struct tty_struct *tty,
574 const unsigned char *cp, char *fp, int count)
576 struct slcan *sl = (struct slcan *) tty->disc_data;
577 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
578 struct net_device_stats *stats = slc_get_stats(sl->dev);
580 struct net_device_stats *stats = &sl->dev->stats;
583 if (!sl || sl->magic != SLCAN_MAGIC ||
584 !netif_running(sl->dev))
587 /* Read the characters out of the buffer */
590 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
595 slcan_unesc(sl, *cp++);
599 /************************************
600 * slcan_open helper routines.
601 ************************************/
603 /* Collect hanged up channels */
605 static void slc_sync(void)
608 struct net_device *dev;
611 for (i = 0; i < maxdev; i++) {
616 sl = netdev_priv(dev);
617 if (sl->tty || sl->leased)
619 if (dev->flags&IFF_UP)
625 /* Find a free SLCAN channel, and link in this `tty' line. */
626 static struct slcan *slc_alloc(dev_t line, char forcednum)
631 struct net_device *dev = NULL;
634 if (slcan_devs == NULL)
635 return NULL; /* Master array missing ! */
637 for (i = 0; i < maxdev; i++) {
642 sl = netdev_priv(dev);
644 if (sl->line != line)
649 /* Clear ESCAPE & ERROR flags */
650 sl->flags &= (1 << SLF_INUSE);
657 if (current->pid == sl->pid) {
658 if (sl->line == line && score < 3) {
669 if (sl->line == line && score < 1) {
680 /* Check if the user specified an exact interface to use */
682 sel = forcednum - '0';
691 if ((score > 1) && (dev)) {
692 sl = netdev_priv(dev);
693 sl->flags &= (1 << SLF_INUSE);
698 /* Sorry, too many, all slots in use */
703 sl = netdev_priv(dev);
704 if (test_bit(SLF_INUSE, &sl->flags)) {
705 unregister_netdevice(dev);
707 slcan_devs[i] = NULL;
713 sprintf(name, "can%d", i);
715 dev = alloc_netdev(sizeof(*sl), name, slc_setup);
721 sl = netdev_priv(dev);
723 /* Initialize channel control data */
724 sl->magic = SLCAN_MAGIC;
726 spin_lock_init(&sl->lock);
733 * Open the high-level part of the SLCAN channel.
734 * This function is called by the TTY module when the
735 * SLCAN line discipline is called for. Because we are
736 * sure the tty line exists, we only have to link it to
737 * a free SLCAN channel...
739 * Called in process context serialized from other ldisc calls.
742 static int slcan_open(struct tty_struct *tty)
747 if (!capable(CAP_NET_ADMIN))
750 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,25)
751 if (tty->ops->write == NULL)
755 /* RTnetlink lock is misused here to serialize concurrent
756 opens of slcan channels. There are better ways, but it is
761 /* Collect hanged up channels. */
764 sl = (struct slcan *) tty->disc_data;
767 /* First make sure we're not already connected. */
768 if (sl && sl->magic == SLCAN_MAGIC)
771 /* OK. Find a free SLCAN channel to use. */
774 /* Look to see if the user has requested a specific channel
775 * to be used (encoded as '0' plus the interface number requested in
776 * the otherwise unused swtch termios variable )
777 * stty swtch 'channel' device
778 * where 'channel' is '0' to maxdevs (0)
779 * where device is the name of the serial device (/dev/ttyUSB0)
781 if ((SWTC_CHAR(tty)>='0') && (SWTC_CHAR(tty)<'0'+maxdev)){
782 sl = slc_alloc(tty_devnum(tty),SWTC_CHAR(tty));
784 /* OK. Find a free SLCAN channel to use. */
785 sl = slc_alloc(tty_devnum(tty),0);
793 sl->line = tty_devnum(tty);
794 sl->pid = current->pid;
796 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
797 /* FIXME: already done before we were called - seems this can go */
798 if (tty->driver->flush_buffer)
799 tty->driver->flush_buffer(tty);
802 if (!test_bit(SLF_INUSE, &sl->flags)) {
803 /* Perform the low-level SLCAN initialization. */
807 set_bit(SLF_INUSE, &sl->flags);
809 err = register_netdevice(sl->dev);
814 /* Done. We have linked the TTY line to a channel. */
817 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,16)
818 tty->receive_room = 65536; /* We don't flow control */
821 return sl->dev->base_addr;
825 tty->disc_data = NULL;
826 clear_bit(SLF_INUSE, &sl->flags);
831 /* Count references from TTY module */
836 * Close down a SLCAN channel.
837 * This means flushing out any pending queues, and then returning. This
838 * call is serialized against other ldisc functions.
840 * We also use this method for a hangup event.
842 static void slcan_close(struct tty_struct *tty)
844 struct slcan *sl = (struct slcan *) tty->disc_data;
846 /* First make sure we're connected. */
847 if (!sl || sl->magic != SLCAN_MAGIC || sl->tty != tty)
850 tty->disc_data = NULL;
855 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
856 /* Flush network side */
857 unregister_netdev(sl->dev);
858 /* This will complete via sl_free_netdev */
860 /* Count references from TTY module */
864 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
865 static int slcan_hangup(struct tty_struct *tty)
872 /* Perform I/O control on an active SLCAN channel. */
873 static int slcan_ioctl(struct tty_struct *tty, struct file *file,
874 unsigned int cmd, unsigned long arg)
876 struct slcan *sl = (struct slcan *) tty->disc_data;
879 /* First make sure we're connected. */
880 if (!sl || sl->magic != SLCAN_MAGIC)
885 tmp = strlen(sl->dev->name) + 1;
886 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
893 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
894 /* Allow stty to read, but not set, the serial port */
897 return n_tty_ioctl(tty, file, cmd, arg);
903 return tty_mode_ioctl(tty, file, cmd, arg);
908 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27)
909 static struct tty_ldisc slc_ldisc = {
911 static struct tty_ldisc_ops slc_ldisc = {
913 .owner = THIS_MODULE,
914 .magic = TTY_LDISC_MAGIC,
917 .close = slcan_close,
918 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,31)
919 .hangup = slcan_hangup,
921 .ioctl = slcan_ioctl,
922 .receive_buf = slcan_receive_buf,
923 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,16)
924 .receive_room = slcan_receive_room,
926 .write_wakeup = slcan_write_wakeup,
929 /************************************
930 * general slcan module init/exit
931 ************************************/
933 static int __init slcan_init(void)
938 maxdev = 4; /* Sanity */
941 printk(KERN_INFO "slcan: %d dynamic interface channels.\n", maxdev);
943 slcan_devs = kmalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
945 printk(KERN_ERR "slcan: can't allocate slcan device array!\n");
949 /* Clear the pointer array, we allocate devices when we need them */
950 memset(slcan_devs, 0, sizeof(struct net_device *)*maxdev);
952 /* Fill in our line protocol discipline, and register it */
953 status = tty_register_ldisc(N_SLCAN, &slc_ldisc);
955 printk(KERN_ERR "slcan: can't register line discipline\n");
961 static void __exit slcan_exit(void)
964 struct net_device *dev;
966 unsigned long timeout = jiffies + HZ;
969 if (slcan_devs == NULL)
972 /* First of all: check for active disciplines and hangup them.
976 msleep_interruptible(100);
979 for (i = 0; i < maxdev; i++) {
983 sl = netdev_priv(dev);
984 spin_lock_bh(&sl->lock);
989 spin_unlock_bh(&sl->lock);
991 } while (busy && time_before(jiffies, timeout));
993 /* FIXME (2.6.32+): hangup is async so we should wait when doing
996 for (i = 0; i < maxdev; i++) {
1000 slcan_devs[i] = NULL;
1002 sl = netdev_priv(dev);
1004 printk(KERN_ERR "%s: tty discipline still running\n",
1006 /* Intentionally leak the control block. */
1007 dev->destructor = NULL;
1010 unregister_netdev(dev);
1016 i = tty_unregister_ldisc(N_SLCAN);
1018 printk(KERN_ERR "slcan: can't unregister ldisc (err %d)\n", i);
1021 module_init(slcan_init);
1022 module_exit(slcan_exit);