2 * sllin.c - serial line LIN 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 * sllin.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/module.h>
43 #include <linux/moduleparam.h>
45 #include <asm/system.h>
46 #include <linux/uaccess.h>
47 #include <linux/bitops.h>
48 #include <linux/string.h>
49 #include <linux/tty.h>
50 #include <linux/errno.h>
51 #include <linux/netdevice.h>
52 #include <linux/skbuff.h>
53 #include <linux/rtnetlink.h>
54 #include <linux/if_arp.h>
55 #include <linux/if_ether.h>
56 #include <linux/sched.h>
57 #include <linux/delay.h>
58 #include <linux/init.h>
59 #include <linux/can.h>
60 #include <linux/kthread.h>
61 #include <linux/hrtimer.h>
63 /* Should be in include/linux/tty.h */
66 static __initdata const char banner[] =
67 KERN_INFO "sllin: serial line LIN interface driver\n";
69 MODULE_ALIAS_LDISC(N_SLLIN);
70 MODULE_DESCRIPTION("serial line LIN interface");
71 MODULE_LICENSE("GPL");
72 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
74 #define SLLIN_MAGIC 0x53CA
75 // #define BREAK_BY_BAUD
77 static int maxdev = 10; /* MAX number of SLLIN channels;
78 This can be overridden with
79 insmod sllin.ko maxdev=nnn */
80 module_param(maxdev, int, 0);
81 MODULE_PARM_DESC(maxdev, "Maximum number of sllin interfaces");
83 /* maximum buffer len to store whole LIN message*/
84 #define SLLIN_DATA_MAX 8
85 #define SLLIN_BUFF_LEN (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
86 SLLIN_DATA_MAX + 1 /*checksum*/)
87 #define SLLIN_BUFF_BREAK 0
88 #define SLLIN_BUFF_SYNC 1
89 #define SLLIN_BUFF_ID 2
90 #define SLLIN_BUFF_DATA 3
92 #define SLLIN_ID_MASK 0x3f
98 SLSTATE_RESPONSE_WAIT,
99 SLSTATE_RESPONSE_SENT,
105 /* Various fields. */
106 struct tty_struct *tty; /* ptr to TTY structure */
107 struct net_device *dev; /* easy for intr handling */
110 /* LIN message buffer and actual processed data counts */
111 unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
112 unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
113 int rx_expect; /* expected number of Rx chars */
114 int rx_lim; /* maximum Rx chars for current frame */
115 int rx_cnt; /* message buffer Rx fill level */
116 int tx_lim; /* actual limit of bytes to Tx */
117 int tx_cnt; /* number of already Tx bytes */
118 char lin_master; /* node is a master node */
119 int lin_baud; /* LIN baudrate */
120 int lin_state; /* state */
121 char id_to_send; /* there is ID to be sent */
122 char data_to_send; /* there are data to be sent */
124 unsigned long flags; /* Flag values/ mode etc */
125 #define SLF_INUSE 0 /* Channel in use */
126 #define SLF_ERROR 1 /* Parity, etc. error */
127 #define SLF_RXEVENT 2 /* Rx wake event */
128 #define SLF_TXEVENT 3 /* Tx wake event */
129 #define SLF_MSGEVENT 4 /* CAN message to sent */
130 #define SLF_TMOUTEVENT 5 /* Timeout on received data */
133 struct task_struct *kwthread;
134 wait_queue_head_t kwt_wq;
135 struct hrtimer rx_timer; /* RX timeout timer */
136 ktime_t rx_timer_timeout; /* RX timeout timer value */
137 struct sk_buff *rec_skb; /* Socket buffer with received CAN frame */
140 static struct net_device **sllin_devs;
142 const unsigned char sllin_id_parity_table[] = {
143 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
144 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
145 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80,
146 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
147 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
148 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
149 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
150 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80
153 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
155 struct ktermios old_termios;
158 mutex_lock(&tty->termios_mutex);
160 old_termios = *(tty->termios);
161 cflag = tty->termios->c_cflag;
162 cflag &= ~(CBAUD | CIBAUD);
164 tty->termios->c_cflag = cflag;
166 tty_encode_baud_rate(tty, speed, speed);
168 if (tty->ops->set_termios)
169 tty->ops->set_termios(tty, &old_termios);
171 mutex_unlock(&tty->termios_mutex);
177 /* Send one completely decapsulated can_frame to the network layer */
178 static void sll_bump(struct sllin *sl)
183 cf.can_id = sl->rx_buff[SLLIN_BUFF_ID] & SLLIN_ID_MASK;
184 cf.can_dlc = sl->rx_cnt - SLLIN_BUFF_DATA;
185 memcpy(&cf.data, sl->rx_buff + SLLIN_BUFF_DATA, cf.can_dlc);
187 skb = dev_alloc_skb(sizeof(struct can_frame));
192 skb->protocol = htons(ETH_P_CAN);
193 skb->pkt_type = PACKET_BROADCAST;
194 skb->ip_summed = CHECKSUM_UNNECESSARY;
195 memcpy(skb_put(skb, sizeof(struct can_frame)),
196 &cf, sizeof(struct can_frame));
199 sl->dev->stats.rx_packets++;
200 sl->dev->stats.rx_bytes += cf.can_dlc;
204 /************************************************************************
205 * STANDARD SLLIN ENCAPSULATION *
206 ************************************************************************/
208 /* Convert particular CAN frame into LIN frame and send it to TTY queue. */
209 static void sll_encaps(struct sllin *sl, struct can_frame *cf)
211 // int actual, idx, i;
212 // char lframe[16] = {0x00, 0x55}; /* Fake break, Sync byte */
213 // struct tty_struct *tty = sl->tty;
215 // pr_debug("sllin: %s() invoked\n", __FUNCTION__);
217 // /* We do care only about SFF frames */
218 // if (cf->can_id & CAN_EFF_FLAG)
221 // /* Send only header */
222 // if (cf->can_id & CAN_RTR_FLAG) {
223 // pr_debug("sllin: %s() RTR CAN frame\n", __FUNCTION__);
224 // lframe[2] = (u8)cf->can_id; /* Get one byte LIN ID */
226 // sltty_change_speed(tty, sl->lin_baud * 2 / 3);
227 // tty->ops->write(tty, &lframe[0], 1);
228 // sltty_change_speed(tty, sl->lin_baud);
229 // tty->ops->write(tty, &lframe[1], 1);
230 // tty->ops->write(tty, &lframe[2], 1);
232 // pr_debug("sllin: %s() non-RTR CAN frame\n", __FUNCTION__);
233 // /* idx = strlen(sl->xbuff);
235 // for (i = 0; i < cf->can_dlc; i++)
236 // sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
238 // * Order of next two lines is *very* important.
239 // * When we are sending a little amount of data,
240 // * the transfer may be completed inside the ops->write()
241 // * routine, because it's running with interrupts enabled.
242 // * In this case we *never* got WRITE_WAKEUP event,
243 // * if we did not request it before write operation.
244 // * 14 Oct 1994 Dmitry Gorodchanin.
246 // set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
247 // actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
248 // sl->xleft = strlen(sl->xbuff) - actual;
249 // sl->xhead = sl->xbuff + actual;
250 // sl->dev->stats.tx_bytes += cf->can_dlc;
257 * Called by the driver when there's room for more data. If we have
258 * more packets to send, we send them here.
260 static void sllin_write_wakeup(struct tty_struct *tty)
264 struct sllin *sl = (struct sllin *) tty->disc_data;
266 /* First make sure we're connected. */
267 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
270 if (sl->lin_state != SLSTATE_BREAK_SENT)
271 remains = sl->tx_lim - sl->tx_cnt;
273 remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
276 actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, sl->tx_cnt - sl->tx_lim);
277 sl->tx_cnt += actual;
279 if (sl->tx_cnt < sl->tx_lim) {
280 printk(KERN_INFO "sllin_write_wakeup sent %d, remains %d, waiting\n",
281 sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
286 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
287 set_bit(SLF_TXEVENT, &sl->flags);
288 wake_up(&sl->kwt_wq);
290 printk(KERN_INFO "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
293 /* Send a can_frame to a TTY queue. */
294 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
296 struct sllin *sl = netdev_priv(dev);
298 if (skb->len != sizeof(struct can_frame))
301 spin_lock(&sl->lock);
302 if (!netif_running(dev)) {
303 spin_unlock(&sl->lock);
304 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
307 if (sl->tty == NULL) {
308 spin_unlock(&sl->lock);
312 netif_stop_queue(sl->dev);
315 set_bit(SLF_MSGEVENT, &sl->flags);
316 wake_up(&sl->kwt_wq);
317 spin_unlock(&sl->lock);
326 /******************************************
327 * Routines looking at netdevice side.
328 ******************************************/
330 /* Netdevice UP -> DOWN routine */
331 static int sll_close(struct net_device *dev)
333 struct sllin *sl = netdev_priv(dev);
335 spin_lock_bh(&sl->lock);
337 /* TTY discipline is running. */
338 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
340 netif_stop_queue(dev);
343 spin_unlock_bh(&sl->lock);
348 /* Netdevice DOWN -> UP routine */
349 static int sll_open(struct net_device *dev)
351 struct sllin *sl = netdev_priv(dev);
353 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
358 sl->flags &= (1 << SLF_INUSE);
359 netif_start_queue(dev);
363 /* Hook the destructor so we can free sllin devs at the right point in time */
364 static void sll_free_netdev(struct net_device *dev)
366 int i = dev->base_addr;
368 sllin_devs[i] = NULL;
371 static const struct net_device_ops sll_netdev_ops = {
372 .ndo_open = sll_open,
373 .ndo_stop = sll_close,
374 .ndo_start_xmit = sll_xmit,
377 static void sll_setup(struct net_device *dev)
379 dev->netdev_ops = &sll_netdev_ops;
380 dev->destructor = sll_free_netdev;
382 dev->hard_header_len = 0;
384 dev->tx_queue_len = 10;
386 dev->mtu = sizeof(struct can_frame);
387 dev->type = ARPHRD_CAN;
389 /* New-style flags. */
390 dev->flags = IFF_NOARP;
391 dev->features = NETIF_F_NO_CSUM;
394 /******************************************
395 Routines looking at TTY side.
396 ******************************************/
399 * Handle the 'receiver data ready' interrupt.
400 * This function is called by the 'tty_io' module in the kernel when
401 * a block of SLLIN data has been received, which can now be decapsulated
402 * and sent on to some IP layer for further processing. This will not
403 * be re-entered while running but other ldisc functions may be called
407 static void sllin_receive_buf(struct tty_struct *tty,
408 const unsigned char *cp, char *fp, int count)
410 struct sllin *sl = (struct sllin *) tty->disc_data;
412 printk(KERN_INFO "sllin_receive_buf invoked\n");
414 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
417 /* Read the characters out of the buffer */
420 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
421 sl->dev->stats.rx_errors++;
422 printk(KERN_INFO "sllin_receive_buf char 0x%02x ignored "
423 "due marker 0x%02x, flags 0x%lx\n",
424 *cp, *(fp-1), sl->flags);
429 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
430 #ifndef BREAK_BY_BAUD
431 /* We didn't receive Break character */
432 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
433 sl->rx_buff[sl->rx_cnt++] = 0x00;
436 printk(KERN_INFO "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
437 sl->rx_buff[sl->rx_cnt++] = *cp++;
441 if (sl->rx_cnt >= sl->rx_expect) {
442 set_bit(SLF_RXEVENT, &sl->flags);
443 wake_up(&sl->kwt_wq);
444 printk(KERN_INFO "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
446 printk(KERN_INFO "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
450 /*****************************************
451 * sllin message helper routines
452 *****************************************/
454 int sllin_setup_msg(struct sllin *sl, int mode, int id,
455 unsigned char *data, int len)
457 if (id > SLLIN_ID_MASK)
463 sl->rx_lim = SLLIN_BUFF_LEN;
465 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
466 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
467 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
468 sl->tx_lim = SLLIN_BUFF_DATA;
470 if ((data != NULL) && len) {
475 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
476 /* compute data parity there */
477 for (i = SLLIN_BUFF_DATA; i < sl->tx_lim; i++) {
478 csum += sl->tx_buff[i];
483 sl->tx_buff[sl->tx_lim++] = csum;
486 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
492 int sllin_send_tx_buff(struct sllin *sl)
494 struct tty_struct *tty = sl->tty;
499 if (sl->lin_state != SLSTATE_BREAK_SENT)
500 remains = sl->tx_lim - sl->tx_cnt;
504 remains = sl->tx_lim - sl->tx_cnt;
507 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
515 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
516 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
518 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
526 printk(KERN_INFO "sllin_send_tx_buff sent %d, remains %d\n",
527 sl->tx_cnt, remains);
533 int sllin_send_break(struct sllin *sl)
535 struct tty_struct *tty = sl->tty;
536 unsigned long break_baud;
539 break_baud = ((sl->lin_baud * 2) / 3);
540 sltty_change_speed(tty, break_baud);
542 tty->ops->flush_buffer(tty);
543 sl->rx_cnt = SLLIN_BUFF_BREAK;
545 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
546 sl->lin_state = SLSTATE_BREAK_SENT;
548 res = sllin_send_tx_buff(sl);
550 sl->lin_state = SLSTATE_IDLE;
556 #else /* BREAK_BY_BAUD */
558 int sllin_send_break(struct sllin *sl)
560 struct tty_struct *tty = sl->tty;
561 unsigned long break_baud;
565 sl->rx_cnt = SLLIN_BUFF_BREAK;
566 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
567 sl->lin_state = SLSTATE_BREAK_SENT;
569 /* Do the break ourselves; Inspired by
570 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
571 retval = tty->ops->break_ctl(tty, -1);
576 usleep_range(650, 750);
578 retval = tty->ops->break_ctl(tty, 0);
579 usleep_range(50, 100);
581 tty->ops->flush_buffer(tty);
583 sl->tx_cnt = SLLIN_BUFF_SYNC;
585 printk(KERN_INFO "sllin: Break sent.\n");
586 set_bit(SLF_RXEVENT, &sl->flags);
587 wake_up(&sl->kwt_wq);
591 #endif /* BREAK_BY_BAUD */
594 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
596 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
598 set_bit(SLF_TMOUTEVENT, &sl->flags);
599 wake_up(&sl->kwt_wq);
601 return HRTIMER_NORESTART;
605 /*****************************************
606 * sllin_kwthread - kernel worker thread
607 *****************************************/
609 int sllin_kwthread(void *ptr)
611 struct sllin *sl = (struct sllin *)ptr;
612 struct tty_struct *tty = sl->tty;
613 struct sched_param schparam = { .sched_priority = 40 };
615 struct can_frame *cf;
617 printk(KERN_INFO "sllin: sllin_kwthread started.\n");
618 sched_setscheduler(current, SCHED_FIFO, &schparam);
620 clear_bit(SLF_ERROR, &sl->flags);
621 sltty_change_speed(tty, sl->lin_baud);
623 while (!kthread_should_stop()) {
624 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
626 if(sllin_send_break(sl) < 0) {
627 /* error processing */
631 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
632 test_bit(SLF_RXEVENT, &sl->flags) ||
633 test_bit(SLF_TXEVENT, &sl->flags) ||
634 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
635 ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)));
637 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
638 printk(KERN_INFO "sllin_kthread RXEVENT \n");
641 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
642 printk(KERN_INFO "sllin_kthread TXEVENT \n");
645 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
646 printk(KERN_INFO "sllin_kthread TMOUTEVENT \n");
649 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
652 sl->id_to_send = false;
653 sl->data_to_send = false;
655 sl->lin_state = SLSTATE_IDLE;
658 if ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)) {
659 cf = (struct can_frame *)sl->rec_skb->data;
661 /* We do care only about SFF frames */
662 if (cf->can_id & CAN_EFF_FLAG)
665 if (cf->can_id & CAN_RTR_FLAG) {
666 printk(KERN_INFO "%s: RTR CAN frame, ID = %x\n",
667 __FUNCTION__, cf->can_id & CAN_SFF_MASK);
668 if (sllin_setup_msg(sl, 0,
669 cf->can_id & CAN_SFF_MASK, NULL, 0) != -1) {
670 sl->id_to_send = true;
671 sl->data_to_send = false;
674 printk(KERN_INFO "%s: NON-RTR CAN frame, ID = %x\n",
675 __FUNCTION__, (int)cf->can_id & CAN_SFF_MASK);
677 if (sllin_setup_msg(sl, 0, cf->can_id & CAN_SFF_MASK,
678 cf->data, cf->can_dlc) != -1) {
679 sl->id_to_send = true;
680 sl->data_to_send = true;
685 clear_bit(SLF_MSGEVENT, &sl->flags);
686 kfree_skb(sl->rec_skb);
687 netif_wake_queue(sl->dev);
690 switch (sl->lin_state) {
691 case SLSTATE_BREAK_SENT:
693 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
696 res = sltty_change_speed(tty, sl->lin_baud);
699 sl->lin_state = SLSTATE_ID_SENT;
700 sllin_send_tx_buff(sl);
703 case SLSTATE_ID_SENT:
704 sl->id_to_send = false;
705 if (sl->data_to_send) {
706 sllin_send_tx_buff(sl);
707 sl->lin_state = SLSTATE_RESPONSE_SENT;
708 sl->rx_expect = sl->tx_lim;
709 goto slstate_response_sent;
711 sl->rx_expect = SLLIN_BUFF_DATA + 2;
712 sl->lin_state = SLSTATE_RESPONSE_WAIT;
713 /* If we don't receive anything, timer will "unblock" us */
714 hrtimer_start(&sl->rx_timer,
715 ktime_add(ktime_get(), sl->rx_timer_timeout),
717 goto slstate_response_wait;
721 case SLSTATE_RESPONSE_WAIT:
722 slstate_response_wait:
723 if (sl->rx_cnt < sl->rx_expect)
726 hrtimer_cancel(&sl->rx_timer);
727 printk(KERN_INFO "sllin: response received ID %d len %d\n",
728 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
729 // check checksum in sl->rx_buff
730 // send CAN non-RTR frame with data
731 printk(KERN_INFO "sllin: sending NON-RTR CAN frame with LIN payload.");
732 sll_bump(sl); //send packet to the network layer
733 sl->id_to_send = false;
734 sl->lin_state = SLSTATE_IDLE;
737 case SLSTATE_RESPONSE_SENT:
738 slstate_response_sent:
739 if (sl->rx_cnt < sl->tx_lim)
742 printk(KERN_INFO "sllin: response sent ID %d len %d\n",
743 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
745 sl->id_to_send = false;
746 sl->lin_state = SLSTATE_IDLE;
753 /* sl->dev->stats.tx_packets++; send frames statistic */
754 /* netif_wake_queue(sl->dev); allow next Tx packet arrival */
757 hrtimer_cancel(&sl->rx_timer);
758 printk(KERN_INFO "sllin: sllin_kwthread stopped.\n");
764 /************************************
765 * sllin_open helper routines.
766 ************************************/
768 /* Collect hanged up channels */
769 static void sll_sync(void)
772 struct net_device *dev;
775 for (i = 0; i < maxdev; i++) {
780 sl = netdev_priv(dev);
783 if (dev->flags & IFF_UP)
788 /* Find a free SLLIN channel, and link in this `tty' line. */
789 static struct sllin *sll_alloc(dev_t line)
792 struct net_device *dev = NULL;
795 if (sllin_devs == NULL)
796 return NULL; /* Master array missing ! */
798 for (i = 0; i < maxdev; i++) {
805 /* Sorry, too many, all slots in use */
810 sl = netdev_priv(dev);
811 if (test_bit(SLF_INUSE, &sl->flags)) {
812 unregister_netdevice(dev);
814 sllin_devs[i] = NULL;
820 sprintf(name, "sllin%d", i);
822 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
828 sl = netdev_priv(dev);
830 /* Initialize channel control data */
831 sl->magic = SLLIN_MAGIC;
833 spin_lock_init(&sl->lock);
840 * Open the high-level part of the SLLIN channel.
841 * This function is called by the TTY module when the
842 * SLLIN line discipline is called for. Because we are
843 * sure the tty line exists, we only have to link it to
844 * a free SLLIN channel...
846 * Called in process context serialized from other ldisc calls.
849 static int sllin_open(struct tty_struct *tty)
853 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
855 if (!capable(CAP_NET_ADMIN))
858 if (tty->ops->write == NULL)
861 /* RTnetlink lock is misused here to serialize concurrent
862 opens of sllin channels. There are better ways, but it is
867 /* Collect hanged up channels. */
873 /* First make sure we're not already connected. */
874 if (sl && sl->magic == SLLIN_MAGIC)
877 /* OK. Find a free SLLIN channel to use. */
879 sl = sll_alloc(tty_devnum(tty));
885 sl->line = tty_devnum(tty);
887 if (!test_bit(SLF_INUSE, &sl->flags)) {
888 /* Perform the low-level SLLIN initialization. */
889 sl->lin_master = true;
893 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
896 sl->id_to_send = false;
897 sl->data_to_send = false;
899 sl->lin_baud = 19200;
901 sl->lin_state = SLSTATE_IDLE;
903 #define SAMPLES_PER_CHAR 10
904 #define CHARS_TO_TIMEOUT 12
905 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
906 sl->rx_timer.function = sllin_rx_timeout_handler;
907 /* timeval_to_ktime(msg_head->ival1); */
908 sl->rx_timer_timeout = ns_to_ktime(
909 (1000000000 / sl->lin_baud) *
910 SAMPLES_PER_CHAR * CHARS_TO_TIMEOUT);
912 set_bit(SLF_INUSE, &sl->flags);
914 init_waitqueue_head(&sl->kwt_wq);
915 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
916 if (sl->kwthread == NULL)
919 err = register_netdevice(sl->dev);
921 goto err_free_chan_and_thread;
924 /* Done. We have linked the TTY line to a channel. */
926 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
928 /* TTY layer expects 0 on success */
931 err_free_chan_and_thread:
932 kthread_stop(sl->kwthread);
937 tty->disc_data = NULL;
938 clear_bit(SLF_INUSE, &sl->flags);
943 /* Count references from TTY module */
948 * Close down a SLLIN channel.
949 * This means flushing out any pending queues, and then returning. This
950 * call is serialized against other ldisc functions.
952 * We also use this method for a hangup event.
955 static void sllin_close(struct tty_struct *tty)
957 struct sllin *sl = (struct sllin *) tty->disc_data;
959 /* First make sure we're connected. */
960 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
963 kthread_stop(sl->kwthread);
966 tty->disc_data = NULL;
969 /* Flush network side */
970 unregister_netdev(sl->dev);
971 /* This will complete via sl_free_netdev */
974 static int sllin_hangup(struct tty_struct *tty)
980 /* Perform I/O control on an active SLLIN channel. */
981 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
982 unsigned int cmd, unsigned long arg)
984 struct sllin *sl = (struct sllin *) tty->disc_data;
987 /* First make sure we're connected. */
988 if (!sl || sl->magic != SLLIN_MAGIC)
993 tmp = strlen(sl->dev->name) + 1;
994 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1002 return tty_mode_ioctl(tty, file, cmd, arg);
1006 static struct tty_ldisc_ops sll_ldisc = {
1007 .owner = THIS_MODULE,
1008 .magic = TTY_LDISC_MAGIC,
1011 .close = sllin_close,
1012 .hangup = sllin_hangup,
1013 .ioctl = sllin_ioctl,
1014 .receive_buf = sllin_receive_buf,
1015 .write_wakeup = sllin_write_wakeup,
1018 static int __init sllin_init(void)
1023 maxdev = 4; /* Sanity */
1026 printk(KERN_INFO "sllin: %d dynamic interface channels.\n", maxdev);
1028 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1030 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1034 /* Fill in our line protocol discipline, and register it */
1035 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1037 printk(KERN_ERR "sllin: can't register line discipline\n");
1043 static void __exit sllin_exit(void)
1046 struct net_device *dev;
1048 unsigned long timeout = jiffies + HZ;
1051 if (sllin_devs == NULL)
1054 /* First of all: check for active disciplines and hangup them.
1058 msleep_interruptible(100);
1061 for (i = 0; i < maxdev; i++) {
1062 dev = sllin_devs[i];
1065 sl = netdev_priv(dev);
1066 spin_lock_bh(&sl->lock);
1069 tty_hangup(sl->tty);
1071 spin_unlock_bh(&sl->lock);
1073 } while (busy && time_before(jiffies, timeout));
1075 /* FIXME: hangup is async so we should wait when doing this second
1078 for (i = 0; i < maxdev; i++) {
1079 dev = sllin_devs[i];
1082 sllin_devs[i] = NULL;
1084 sl = netdev_priv(dev);
1086 printk(KERN_ERR "%s: tty discipline still running\n",
1088 /* Intentionally leak the control block. */
1089 dev->destructor = NULL;
1092 unregister_netdev(dev);
1098 i = tty_unregister_ldisc(N_SLLIN);
1100 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1103 module_init(sllin_init);
1104 module_exit(sllin_exit);