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
96 SLSTATE_RESPONSE_WAIT,
97 SLSTATE_RESPONSE_SENT,
103 /* Various fields. */
104 struct tty_struct *tty; /* ptr to TTY structure */
105 struct net_device *dev; /* easy for intr handling */
108 /* LIN message buffer and actual processed data counts */
109 unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
110 unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
111 int rx_expect; /* expected number of Rx chars */
112 int rx_lim; /* maximum Rx chars for current frame */
113 int rx_cnt; /* message buffer Rx fill level */
114 int tx_lim; /* actual limit of bytes to Tx */
115 int tx_cnt; /* number of already Tx bytes */
116 char lin_master; /* node is a master node */
117 int lin_baud; /* LIN baudrate */
118 int lin_state; /* state */
119 char id_to_send; /* there is ID to be sent */
120 char data_to_send; /* there are data to be sent */
122 unsigned long flags; /* Flag values/ mode etc */
123 #define SLF_INUSE 0 /* Channel in use */
124 #define SLF_ERROR 1 /* Parity, etc. error */
125 #define SLF_RXEVENT 2 /* Rx wake event */
126 #define SLF_TXEVENT 3 /* Tx wake event */
127 #define SLF_MSGEVENT 4 /* CAN message to sent */
128 #define SLF_TMOUTEVENT 5 /* Timeout on received data */
131 struct task_struct *kwthread;
132 wait_queue_head_t kwt_wq;
133 struct hrtimer rx_timer; /* RX timeout timer */
134 ktime_t rx_timer_timeout; /* RX timeout timer value */
135 struct sk_buff *rec_skb; /* Socket buffer with received CAN frame */
138 static struct net_device **sllin_devs;
140 const unsigned char sllin_id_parity_table[] = {
141 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
142 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
143 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80,
144 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
145 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
146 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
147 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
148 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80
151 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
153 struct ktermios old_termios;
156 mutex_lock(&tty->termios_mutex);
158 old_termios = *(tty->termios);
159 cflag = tty->termios->c_cflag;
160 cflag &= ~(CBAUD | CIBAUD);
162 tty->termios->c_cflag = cflag;
164 tty_encode_baud_rate(tty, speed, speed);
166 if (tty->ops->set_termios)
167 tty->ops->set_termios(tty, &old_termios);
169 mutex_unlock(&tty->termios_mutex);
175 /* Send one completely decapsulated can_frame to the network layer */
176 static void sll_bump(struct sllin *sl)
178 // struct sk_buff *skb;
179 // struct can_frame cf;
180 // int i, dlc_pos, tmp;
181 // unsigned long ultmp;
182 // char cmd = sl->rbuff[0];
184 // if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
187 // if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
188 // dlc_pos = 4; /* dlc position tiiid */
190 // dlc_pos = 9; /* dlc position Tiiiiiiiid */
192 // if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
195 // cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
197 // sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
199 // if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
202 // cf.can_id = ultmp;
204 // if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
205 // cf.can_id |= CAN_EFF_FLAG;
207 // if ((cmd | 0x20) == 'r') /* RTR frame */
208 // cf.can_id |= CAN_RTR_FLAG;
210 // *(u64 *) (&cf.data) = 0; /* clear payload */
212 // for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
214 // tmp = asc2nibble(sl->rbuff[dlc_pos++]);
217 // cf.data[i] = (tmp << 4);
218 // tmp = asc2nibble(sl->rbuff[dlc_pos++]);
221 // cf.data[i] |= tmp;
225 // skb = dev_alloc_skb(sizeof(struct can_frame));
229 // skb->dev = sl->dev;
230 // skb->protocol = htons(ETH_P_CAN);
231 // skb->pkt_type = PACKET_BROADCAST;
232 // skb->ip_summed = CHECKSUM_UNNECESSARY;
233 // memcpy(skb_put(skb, sizeof(struct can_frame)),
234 // &cf, sizeof(struct can_frame));
237 // sl->dev->stats.rx_packets++;
238 // sl->dev->stats.rx_bytes += cf.can_dlc;
242 /************************************************************************
243 * STANDARD SLLIN ENCAPSULATION *
244 ************************************************************************/
246 /* Convert particular CAN frame into LIN frame and send it to TTY queue. */
247 static void sll_encaps(struct sllin *sl, struct can_frame *cf)
249 // int actual, idx, i;
250 // char lframe[16] = {0x00, 0x55}; /* Fake break, Sync byte */
251 // struct tty_struct *tty = sl->tty;
253 // pr_debug("sllin: %s() invoked\n", __FUNCTION__);
255 // /* We do care only about SFF frames */
256 // if (cf->can_id & CAN_EFF_FLAG)
259 // /* Send only header */
260 // if (cf->can_id & CAN_RTR_FLAG) {
261 // pr_debug("sllin: %s() RTR CAN frame\n", __FUNCTION__);
262 // lframe[2] = (u8)cf->can_id; /* Get one byte LIN ID */
264 // sltty_change_speed(tty, sl->lin_baud * 2 / 3);
265 // tty->ops->write(tty, &lframe[0], 1);
266 // sltty_change_speed(tty, sl->lin_baud);
267 // tty->ops->write(tty, &lframe[1], 1);
268 // tty->ops->write(tty, &lframe[2], 1);
270 // pr_debug("sllin: %s() non-RTR CAN frame\n", __FUNCTION__);
271 // /* idx = strlen(sl->xbuff);
273 // for (i = 0; i < cf->can_dlc; i++)
274 // sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
276 // * Order of next two lines is *very* important.
277 // * When we are sending a little amount of data,
278 // * the transfer may be completed inside the ops->write()
279 // * routine, because it's running with interrupts enabled.
280 // * In this case we *never* got WRITE_WAKEUP event,
281 // * if we did not request it before write operation.
282 // * 14 Oct 1994 Dmitry Gorodchanin.
284 // set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
285 // actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
286 // sl->xleft = strlen(sl->xbuff) - actual;
287 // sl->xhead = sl->xbuff + actual;
288 // sl->dev->stats.tx_bytes += cf->can_dlc;
295 * Called by the driver when there's room for more data. If we have
296 * more packets to send, we send them here.
298 static void sllin_write_wakeup(struct tty_struct *tty)
302 struct sllin *sl = (struct sllin *) tty->disc_data;
304 /* First make sure we're connected. */
305 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
308 if (sl->lin_state != SLSTATE_BREAK_SENT)
309 remains = sl->tx_lim - sl->tx_cnt;
311 remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
314 actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, sl->tx_cnt - sl->tx_lim);
315 sl->tx_cnt += actual;
317 if (sl->tx_cnt < sl->tx_lim) {
318 printk(KERN_INFO "sllin_write_wakeup sent %d, remains %d, waiting\n",
319 sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
324 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
325 set_bit(SLF_TXEVENT, &sl->flags);
326 wake_up(&sl->kwt_wq);
328 printk(KERN_INFO "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
331 /* Send a can_frame to a TTY queue. */
332 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
334 struct sllin *sl = netdev_priv(dev);
336 if (skb->len != sizeof(struct can_frame))
339 spin_lock(&sl->lock);
340 if (!netif_running(dev)) {
341 spin_unlock(&sl->lock);
342 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
345 if (sl->tty == NULL) {
346 spin_unlock(&sl->lock);
350 netif_stop_queue(sl->dev);
353 set_bit(SLF_MSGEVENT, &sl->flags);
354 wake_up(&sl->kwt_wq);
355 spin_unlock(&sl->lock);
364 /******************************************
365 * Routines looking at netdevice side.
366 ******************************************/
368 /* Netdevice UP -> DOWN routine */
369 static int sll_close(struct net_device *dev)
371 struct sllin *sl = netdev_priv(dev);
373 spin_lock_bh(&sl->lock);
375 /* TTY discipline is running. */
376 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
378 netif_stop_queue(dev);
381 spin_unlock_bh(&sl->lock);
386 /* Netdevice DOWN -> UP routine */
387 static int sll_open(struct net_device *dev)
389 struct sllin *sl = netdev_priv(dev);
391 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
396 sl->flags &= (1 << SLF_INUSE);
397 netif_start_queue(dev);
401 /* Hook the destructor so we can free sllin devs at the right point in time */
402 static void sll_free_netdev(struct net_device *dev)
404 int i = dev->base_addr;
406 sllin_devs[i] = NULL;
409 static const struct net_device_ops sll_netdev_ops = {
410 .ndo_open = sll_open,
411 .ndo_stop = sll_close,
412 .ndo_start_xmit = sll_xmit,
415 static void sll_setup(struct net_device *dev)
417 dev->netdev_ops = &sll_netdev_ops;
418 dev->destructor = sll_free_netdev;
420 dev->hard_header_len = 0;
422 dev->tx_queue_len = 10;
424 dev->mtu = sizeof(struct can_frame);
425 dev->type = ARPHRD_CAN;
427 /* New-style flags. */
428 dev->flags = IFF_NOARP;
429 dev->features = NETIF_F_NO_CSUM;
432 /******************************************
433 Routines looking at TTY side.
434 ******************************************/
437 * Handle the 'receiver data ready' interrupt.
438 * This function is called by the 'tty_io' module in the kernel when
439 * a block of SLLIN data has been received, which can now be decapsulated
440 * and sent on to some IP layer for further processing. This will not
441 * be re-entered while running but other ldisc functions may be called
445 static void sllin_receive_buf(struct tty_struct *tty,
446 const unsigned char *cp, char *fp, int count)
448 struct sllin *sl = (struct sllin *) tty->disc_data;
450 printk(KERN_INFO "sllin_receive_buf invoked\n");
452 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
455 /* Read the characters out of the buffer */
458 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
459 sl->dev->stats.rx_errors++;
460 printk(KERN_INFO "sllin_receive_buf char 0x%02x ignored "
461 "due marker 0x%02x, flags 0x%lx\n",
462 *cp, *(fp-1), sl->flags);
467 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
468 #ifndef BREAK_BY_BAUD
469 /* We didn't receive Break character */
470 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
471 sl->rx_buff[sl->rx_cnt++] = 0x00;
474 printk(KERN_INFO "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
475 sl->rx_buff[sl->rx_cnt++] = *cp++;
479 if (sl->rx_cnt >= sl->rx_expect) {
480 set_bit(SLF_RXEVENT, &sl->flags);
481 wake_up(&sl->kwt_wq);
482 printk(KERN_INFO "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
484 printk(KERN_INFO "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
488 /*****************************************
489 * sllin message helper routines
490 *****************************************/
492 int sllin_setup_msg(struct sllin *sl, int mode, int id,
493 unsigned char *data, int len)
501 sl->rx_lim = SLLIN_BUFF_LEN;
503 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
504 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
505 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
506 sl->tx_lim = SLLIN_BUFF_DATA;
508 if ((data != NULL) && len) {
513 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
514 /* compute data parity there */
515 for (i = SLLIN_BUFF_DATA; i < sl->tx_lim; i++) {
516 csum += sl->tx_buff[i];
521 sl->tx_buff[sl->tx_lim++] = csum;
524 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
530 int sllin_send_tx_buff(struct sllin *sl)
532 struct tty_struct *tty = sl->tty;
537 if (sl->lin_state != SLSTATE_BREAK_SENT)
538 remains = sl->tx_lim - sl->tx_cnt;
542 remains = sl->tx_lim - sl->tx_cnt;
545 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
553 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
554 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
556 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
564 printk(KERN_INFO "sllin_send_tx_buff sent %d, remains %d\n",
565 sl->tx_cnt, remains);
571 int sllin_send_break(struct sllin *sl)
573 struct tty_struct *tty = sl->tty;
574 unsigned long break_baud;
577 break_baud = ((sl->lin_baud * 2) / 3);
578 sltty_change_speed(tty, break_baud);
580 tty->ops->flush_buffer(tty);
581 sl->rx_cnt = SLLIN_BUFF_BREAK;
583 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
584 sl->lin_state = SLSTATE_BREAK_SENT;
586 res = sllin_send_tx_buff(sl);
588 sl->lin_state = SLSTATE_IDLE;
594 #else /* BREAK_BY_BAUD */
596 int sllin_send_break(struct sllin *sl)
598 struct tty_struct *tty = sl->tty;
599 unsigned long break_baud;
603 sl->rx_cnt = SLLIN_BUFF_BREAK;
604 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
605 sl->lin_state = SLSTATE_BREAK_SENT;
607 /* Do the break ourselves; Inspired by
608 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
609 retval = tty->ops->break_ctl(tty, -1);
614 usleep_range(650, 750);
616 retval = tty->ops->break_ctl(tty, 0);
617 usleep_range(50, 100);
619 tty->ops->flush_buffer(tty);
621 sl->tx_cnt = SLLIN_BUFF_SYNC;
623 printk(KERN_INFO "sllin: Break sent.\n");
624 set_bit(SLF_RXEVENT, &sl->flags);
625 wake_up(&sl->kwt_wq);
629 #endif /* BREAK_BY_BAUD */
632 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
634 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
636 set_bit(SLF_TMOUTEVENT, &sl->flags);
637 wake_up(&sl->kwt_wq);
639 return HRTIMER_NORESTART;
643 /*****************************************
644 * sllin_kwthread - kernel worker thread
645 *****************************************/
647 int sllin_kwthread(void *ptr)
649 struct sllin *sl = (struct sllin *)ptr;
650 struct tty_struct *tty = sl->tty;
651 struct sched_param schparam = { .sched_priority = 40 };
653 struct can_frame *cf;
655 printk(KERN_INFO "sllin: sllin_kwthread started.\n");
656 sched_setscheduler(current, SCHED_FIFO, &schparam);
658 clear_bit(SLF_ERROR, &sl->flags);
659 sltty_change_speed(tty, sl->lin_baud);
661 while (!kthread_should_stop()) {
662 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
664 if(sllin_send_break(sl) < 0) {
665 /* error processing */
669 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
670 test_bit(SLF_RXEVENT, &sl->flags) ||
671 test_bit(SLF_TXEVENT, &sl->flags) ||
672 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
673 ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)));
675 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
676 printk(KERN_INFO "sllin_kthread RXEVENT \n");
679 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
680 printk(KERN_INFO "sllin_kthread TXEVENT \n");
683 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
684 printk(KERN_INFO "sllin_kthread TMOUTEVENT \n");
687 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
690 sl->id_to_send = false;
691 sl->data_to_send = false;
693 sl->lin_state = SLSTATE_IDLE;
696 if ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)) {
697 cf = (struct can_frame *)sl->rec_skb->data;
699 /* We do care only about SFF frames */
700 if (cf->can_id & CAN_EFF_FLAG)
703 if (cf->can_id & CAN_RTR_FLAG) {
704 printk(KERN_INFO "%s: RTR CAN frame, ID = %x\n",
705 __FUNCTION__, cf->can_id & CAN_SFF_MASK);
706 if (sllin_setup_msg(sl, 0,
707 cf->can_id & CAN_SFF_MASK, NULL, 0) != -1) {
708 sl->id_to_send = true;
709 sl->data_to_send = false;
712 printk(KERN_INFO "%s: NON-RTR CAN frame, ID = %x\n",
713 __FUNCTION__, (int)cf->can_id & CAN_SFF_MASK);
715 if (sllin_setup_msg(sl, 0, cf->can_id & CAN_SFF_MASK,
716 cf->data, cf->can_dlc) != -1) {
717 sl->id_to_send = true;
718 sl->data_to_send = true;
723 clear_bit(SLF_MSGEVENT, &sl->flags);
724 kfree_skb(sl->rec_skb);
725 netif_wake_queue(sl->dev);
728 switch (sl->lin_state) {
729 case SLSTATE_BREAK_SENT:
731 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
734 res = sltty_change_speed(tty, sl->lin_baud);
737 sl->lin_state = SLSTATE_ID_SENT;
738 sllin_send_tx_buff(sl);
741 case SLSTATE_ID_SENT:
742 sl->id_to_send = false;
743 if (sl->data_to_send) {
744 sllin_send_tx_buff(sl);
745 sl->lin_state = SLSTATE_RESPONSE_SENT;
746 sl->rx_expect = sl->tx_lim;
747 goto slstate_response_sent;
749 sl->rx_expect = SLLIN_BUFF_DATA + 2;
750 sl->lin_state = SLSTATE_RESPONSE_WAIT;
751 /* If we don't receive anything, timer will "unblock" us */
752 hrtimer_start(&sl->rx_timer,
753 ktime_add(ktime_get(), sl->rx_timer_timeout),
755 goto slstate_response_wait;
759 case SLSTATE_RESPONSE_WAIT:
760 slstate_response_wait:
761 if (sl->rx_cnt < sl->rx_expect)
764 hrtimer_cancel(&sl->rx_timer);
765 printk(KERN_INFO "sllin: response received ID %d len %d\n",
766 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
767 // check checksum in sl->rx_buff
768 // send CAN non-RTR frame with data
769 sl->id_to_send = false;
770 sl->lin_state = SLSTATE_IDLE;
773 case SLSTATE_RESPONSE_SENT:
774 slstate_response_sent:
775 if (sl->rx_cnt < sl->tx_lim)
778 printk(KERN_INFO "sllin: response sent ID %d len %d\n",
779 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
781 sl->id_to_send = false;
782 sl->lin_state = SLSTATE_IDLE;
788 /* sll_bump(sl); send packet to the network layer */
790 /* sl->dev->stats.tx_packets++; send frames statistic */
791 /* netif_wake_queue(sl->dev); allow next Tx packet arrival */
794 hrtimer_cancel(&sl->rx_timer);
795 printk(KERN_INFO "sllin: sllin_kwthread stopped.\n");
801 /************************************
802 * sllin_open helper routines.
803 ************************************/
805 /* Collect hanged up channels */
806 static void sll_sync(void)
809 struct net_device *dev;
812 for (i = 0; i < maxdev; i++) {
817 sl = netdev_priv(dev);
820 if (dev->flags & IFF_UP)
825 /* Find a free SLLIN channel, and link in this `tty' line. */
826 static struct sllin *sll_alloc(dev_t line)
829 struct net_device *dev = NULL;
832 if (sllin_devs == NULL)
833 return NULL; /* Master array missing ! */
835 for (i = 0; i < maxdev; i++) {
842 /* Sorry, too many, all slots in use */
847 sl = netdev_priv(dev);
848 if (test_bit(SLF_INUSE, &sl->flags)) {
849 unregister_netdevice(dev);
851 sllin_devs[i] = NULL;
857 sprintf(name, "sllin%d", i);
859 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
865 sl = netdev_priv(dev);
867 /* Initialize channel control data */
868 sl->magic = SLLIN_MAGIC;
870 spin_lock_init(&sl->lock);
877 * Open the high-level part of the SLLIN channel.
878 * This function is called by the TTY module when the
879 * SLLIN line discipline is called for. Because we are
880 * sure the tty line exists, we only have to link it to
881 * a free SLLIN channel...
883 * Called in process context serialized from other ldisc calls.
886 static int sllin_open(struct tty_struct *tty)
890 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
892 if (!capable(CAP_NET_ADMIN))
895 if (tty->ops->write == NULL)
898 /* RTnetlink lock is misused here to serialize concurrent
899 opens of sllin channels. There are better ways, but it is
904 /* Collect hanged up channels. */
910 /* First make sure we're not already connected. */
911 if (sl && sl->magic == SLLIN_MAGIC)
914 /* OK. Find a free SLLIN channel to use. */
916 sl = sll_alloc(tty_devnum(tty));
922 sl->line = tty_devnum(tty);
924 if (!test_bit(SLF_INUSE, &sl->flags)) {
925 /* Perform the low-level SLLIN initialization. */
926 sl->lin_master = true;
930 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
933 sl->id_to_send = false;
934 sl->data_to_send = false;
936 sl->lin_baud = 19200;
938 sl->lin_state = SLSTATE_IDLE;
940 #define SAMPLES_PER_CHAR 10
941 #define CHARS_TO_TIMEOUT 6
942 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
943 sl->rx_timer.function = sllin_rx_timeout_handler;
944 /* timeval_to_ktime(msg_head->ival1); */
945 sl->rx_timer_timeout = ns_to_ktime(
946 (1000000000 / sl->lin_baud) *
947 SAMPLES_PER_CHAR * CHARS_TO_TIMEOUT);
949 set_bit(SLF_INUSE, &sl->flags);
951 init_waitqueue_head(&sl->kwt_wq);
952 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
953 if (sl->kwthread == NULL)
956 err = register_netdevice(sl->dev);
958 goto err_free_chan_and_thread;
961 /* Done. We have linked the TTY line to a channel. */
963 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
965 /* TTY layer expects 0 on success */
968 err_free_chan_and_thread:
969 kthread_stop(sl->kwthread);
974 tty->disc_data = NULL;
975 clear_bit(SLF_INUSE, &sl->flags);
980 /* Count references from TTY module */
985 * Close down a SLLIN channel.
986 * This means flushing out any pending queues, and then returning. This
987 * call is serialized against other ldisc functions.
989 * We also use this method for a hangup event.
992 static void sllin_close(struct tty_struct *tty)
994 struct sllin *sl = (struct sllin *) tty->disc_data;
996 /* First make sure we're connected. */
997 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
1000 kthread_stop(sl->kwthread);
1001 sl->kwthread = NULL;
1003 tty->disc_data = NULL;
1006 /* Flush network side */
1007 unregister_netdev(sl->dev);
1008 /* This will complete via sl_free_netdev */
1011 static int sllin_hangup(struct tty_struct *tty)
1017 /* Perform I/O control on an active SLLIN channel. */
1018 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
1019 unsigned int cmd, unsigned long arg)
1021 struct sllin *sl = (struct sllin *) tty->disc_data;
1024 /* First make sure we're connected. */
1025 if (!sl || sl->magic != SLLIN_MAGIC)
1030 tmp = strlen(sl->dev->name) + 1;
1031 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1039 return tty_mode_ioctl(tty, file, cmd, arg);
1043 static struct tty_ldisc_ops sll_ldisc = {
1044 .owner = THIS_MODULE,
1045 .magic = TTY_LDISC_MAGIC,
1048 .close = sllin_close,
1049 .hangup = sllin_hangup,
1050 .ioctl = sllin_ioctl,
1051 .receive_buf = sllin_receive_buf,
1052 .write_wakeup = sllin_write_wakeup,
1055 static int __init sllin_init(void)
1060 maxdev = 4; /* Sanity */
1063 printk(KERN_INFO "sllin: %d dynamic interface channels.\n", maxdev);
1065 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1067 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1071 /* Fill in our line protocol discipline, and register it */
1072 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1074 printk(KERN_ERR "sllin: can't register line discipline\n");
1080 static void __exit sllin_exit(void)
1083 struct net_device *dev;
1085 unsigned long timeout = jiffies + HZ;
1088 if (sllin_devs == NULL)
1091 /* First of all: check for active disciplines and hangup them.
1095 msleep_interruptible(100);
1098 for (i = 0; i < maxdev; i++) {
1099 dev = sllin_devs[i];
1102 sl = netdev_priv(dev);
1103 spin_lock_bh(&sl->lock);
1106 tty_hangup(sl->tty);
1108 spin_unlock_bh(&sl->lock);
1110 } while (busy && time_before(jiffies, timeout));
1112 /* FIXME: hangup is async so we should wait when doing this second
1115 for (i = 0; i < maxdev; i++) {
1116 dev = sllin_devs[i];
1119 sllin_devs[i] = NULL;
1121 sl = netdev_priv(dev);
1123 printk(KERN_ERR "%s: tty discipline still running\n",
1125 /* Intentionally leak the control block. */
1126 dev->destructor = NULL;
1129 unregister_netdev(dev);
1135 i = tty_unregister_ldisc(N_SLLIN);
1137 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1140 module_init(sllin_init);
1141 module_exit(sllin_exit);