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>
62 /* Should be in include/linux/tty.h */
65 static __initdata const char banner[] =
66 KERN_INFO "sllin: serial line LIN interface driver\n";
68 MODULE_ALIAS_LDISC(N_SLLIN);
69 MODULE_DESCRIPTION("serial line LIN interface");
70 MODULE_LICENSE("GPL");
71 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
73 #define SLLIN_MAGIC 0x53CA
74 // #define BREAK_BY_BAUD
76 static int maxdev = 10; /* MAX number of SLLIN channels;
77 This can be overridden with
78 insmod sllin.ko maxdev=nnn */
79 module_param(maxdev, int, 0);
80 MODULE_PARM_DESC(maxdev, "Maximum number of sllin interfaces");
82 /* maximum buffer len to store whole LIN message*/
83 #define SLLIN_DATA_MAX 8
84 #define SLLIN_BUFF_LEN (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
85 SLLIN_DATA_MAX + 1 /*checksum*/)
86 #define SLLIN_BUFF_BREAK 0
87 #define SLLIN_BUFF_SYNC 1
88 #define SLLIN_BUFF_ID 2
89 #define SLLIN_BUFF_DATA 3
95 SLSTATE_RESPONSE_WAIT,
96 SLSTATE_RESPONSE_SENT,
102 /* Various fields. */
103 struct tty_struct *tty; /* ptr to TTY structure */
104 struct net_device *dev; /* easy for intr handling */
107 /* LIN message buffer and actual processed data counts */
108 unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
109 unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
110 int rx_expect; /* expected number of Rx chars */
111 int rx_lim; /* maximum Rx chars for current frame */
112 int rx_cnt; /* message buffer Rx fill level */
113 int tx_lim; /* actual limit of bytes to Tx */
114 int tx_cnt; /* number of already Tx bytes */
115 char lin_master; /* node is a master node */
116 int lin_baud; /* LIN baudrate */
117 int lin_state; /* state */
118 char id_to_send; /* there is ID to be sent */
119 char data_to_send; /* there are data to be sent */
121 unsigned long flags; /* Flag values/ mode etc */
122 #define SLF_INUSE 0 /* Channel in use */
123 #define SLF_ERROR 1 /* Parity, etc. error */
124 #define SLF_RXEVENT 2 /* Rx wake event */
125 #define SLF_TXEVENT 3 /* Tx wake event */
126 #define SLF_MSGEVENT 4 /* CAN message to sent */
129 struct task_struct *kwthread;
130 wait_queue_head_t kwt_wq;
132 struct sk_buff *rec_skb; /* Socket buffer with received CAN frame */
135 static struct net_device **sllin_devs;
137 const unsigned char sllin_id_parity_table[] = {
138 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
139 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
140 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80,
141 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
142 0x00,0x40,0xc0,0x80,0x40,0x00,0x80,0xc0,
143 0x80,0xc0,0x40,0x00,0xc0,0x80,0x00,0x40,
144 0xc0,0x80,0x00,0x40,0x80,0xc0,0x40,0x00,
145 0x40,0x00,0x80,0xc0,0x00,0x40,0xc0,0x80
148 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
150 struct ktermios old_termios;
153 mutex_lock(&tty->termios_mutex);
155 old_termios = *(tty->termios);
156 cflag = tty->termios->c_cflag;
157 cflag &= ~(CBAUD | CIBAUD);
159 tty->termios->c_cflag = cflag;
161 tty_encode_baud_rate(tty, speed, speed);
163 if (tty->ops->set_termios)
164 tty->ops->set_termios(tty, &old_termios);
166 mutex_unlock(&tty->termios_mutex);
172 /* Send one completely decapsulated can_frame to the network layer */
173 static void sll_bump(struct sllin *sl)
175 // struct sk_buff *skb;
176 // struct can_frame cf;
177 // int i, dlc_pos, tmp;
178 // unsigned long ultmp;
179 // char cmd = sl->rbuff[0];
181 // if ((cmd != 't') && (cmd != 'T') && (cmd != 'r') && (cmd != 'R'))
184 // if (cmd & 0x20) /* tiny chars 'r' 't' => standard frame format */
185 // dlc_pos = 4; /* dlc position tiiid */
187 // dlc_pos = 9; /* dlc position Tiiiiiiiid */
189 // if (!((sl->rbuff[dlc_pos] >= '0') && (sl->rbuff[dlc_pos] < '9')))
192 // cf.can_dlc = sl->rbuff[dlc_pos] - '0'; /* get can_dlc from ASCII val */
194 // sl->rbuff[dlc_pos] = 0; /* terminate can_id string */
196 // if (strict_strtoul(sl->rbuff+1, 16, &ultmp))
199 // cf.can_id = ultmp;
201 // if (!(cmd & 0x20)) /* NO tiny chars => extended frame format */
202 // cf.can_id |= CAN_EFF_FLAG;
204 // if ((cmd | 0x20) == 'r') /* RTR frame */
205 // cf.can_id |= CAN_RTR_FLAG;
207 // *(u64 *) (&cf.data) = 0; /* clear payload */
209 // for (i = 0, dlc_pos++; i < cf.can_dlc; i++) {
211 // tmp = asc2nibble(sl->rbuff[dlc_pos++]);
214 // cf.data[i] = (tmp << 4);
215 // tmp = asc2nibble(sl->rbuff[dlc_pos++]);
218 // cf.data[i] |= tmp;
222 // skb = dev_alloc_skb(sizeof(struct can_frame));
226 // skb->dev = sl->dev;
227 // skb->protocol = htons(ETH_P_CAN);
228 // skb->pkt_type = PACKET_BROADCAST;
229 // skb->ip_summed = CHECKSUM_UNNECESSARY;
230 // memcpy(skb_put(skb, sizeof(struct can_frame)),
231 // &cf, sizeof(struct can_frame));
234 // sl->dev->stats.rx_packets++;
235 // sl->dev->stats.rx_bytes += cf.can_dlc;
239 /************************************************************************
240 * STANDARD SLLIN ENCAPSULATION *
241 ************************************************************************/
243 /* Convert particular CAN frame into LIN frame and send it to TTY queue. */
244 static void sll_encaps(struct sllin *sl, struct can_frame *cf)
246 // int actual, idx, i;
247 // char lframe[16] = {0x00, 0x55}; /* Fake break, Sync byte */
248 // struct tty_struct *tty = sl->tty;
250 // pr_debug("sllin: %s() invoked\n", __FUNCTION__);
252 // /* We do care only about SFF frames */
253 // if (cf->can_id & CAN_EFF_FLAG)
256 // /* Send only header */
257 // if (cf->can_id & CAN_RTR_FLAG) {
258 // pr_debug("sllin: %s() RTR CAN frame\n", __FUNCTION__);
259 // lframe[2] = (u8)cf->can_id; /* Get one byte LIN ID */
261 // sltty_change_speed(tty, sl->lin_baud * 2 / 3);
262 // tty->ops->write(tty, &lframe[0], 1);
263 // sltty_change_speed(tty, sl->lin_baud);
264 // tty->ops->write(tty, &lframe[1], 1);
265 // tty->ops->write(tty, &lframe[2], 1);
267 // pr_debug("sllin: %s() non-RTR CAN frame\n", __FUNCTION__);
268 // /* idx = strlen(sl->xbuff);
270 // for (i = 0; i < cf->can_dlc; i++)
271 // sprintf(&sl->xbuff[idx + 2*i], "%02X", cf->data[i]);
273 // * Order of next two lines is *very* important.
274 // * When we are sending a little amount of data,
275 // * the transfer may be completed inside the ops->write()
276 // * routine, because it's running with interrupts enabled.
277 // * In this case we *never* got WRITE_WAKEUP event,
278 // * if we did not request it before write operation.
279 // * 14 Oct 1994 Dmitry Gorodchanin.
281 // set_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
282 // actual = sl->tty->ops->write(sl->tty, sl->xbuff, strlen(sl->xbuff));
283 // sl->xleft = strlen(sl->xbuff) - actual;
284 // sl->xhead = sl->xbuff + actual;
285 // sl->dev->stats.tx_bytes += cf->can_dlc;
292 * Called by the driver when there's room for more data. If we have
293 * more packets to send, we send them here.
295 static void sllin_write_wakeup(struct tty_struct *tty)
299 struct sllin *sl = (struct sllin *) tty->disc_data;
301 /* First make sure we're connected. */
302 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
305 if (sl->lin_state != SLSTATE_BREAK_SENT)
306 remains = sl->tx_lim - sl->tx_cnt;
308 remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
311 actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, sl->tx_cnt - sl->tx_lim);
312 sl->tx_cnt += actual;
314 if (sl->tx_cnt < sl->tx_lim) {
315 printk(KERN_INFO "sllin_write_wakeup sent %d, remains %d, waiting\n",
316 sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
321 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
322 set_bit(SLF_TXEVENT, &sl->flags);
323 wake_up(&sl->kwt_wq);
325 printk(KERN_INFO "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
328 /* Send a can_frame to a TTY queue. */
329 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
331 struct sllin *sl = netdev_priv(dev);
333 if (skb->len != sizeof(struct can_frame))
336 spin_lock(&sl->lock);
337 if (!netif_running(dev)) {
338 spin_unlock(&sl->lock);
339 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
342 if (sl->tty == NULL) {
343 spin_unlock(&sl->lock);
347 netif_stop_queue(sl->dev);
350 set_bit(SLF_MSGEVENT, &sl->flags);
351 wake_up(&sl->kwt_wq);
352 spin_unlock(&sl->lock);
361 /******************************************
362 * Routines looking at netdevice side.
363 ******************************************/
365 /* Netdevice UP -> DOWN routine */
366 static int sll_close(struct net_device *dev)
368 struct sllin *sl = netdev_priv(dev);
370 spin_lock_bh(&sl->lock);
372 /* TTY discipline is running. */
373 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
375 netif_stop_queue(dev);
378 spin_unlock_bh(&sl->lock);
383 /* Netdevice DOWN -> UP routine */
384 static int sll_open(struct net_device *dev)
386 struct sllin *sl = netdev_priv(dev);
388 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
393 sl->flags &= (1 << SLF_INUSE);
394 netif_start_queue(dev);
398 /* Hook the destructor so we can free sllin devs at the right point in time */
399 static void sll_free_netdev(struct net_device *dev)
401 int i = dev->base_addr;
403 sllin_devs[i] = NULL;
406 static const struct net_device_ops sll_netdev_ops = {
407 .ndo_open = sll_open,
408 .ndo_stop = sll_close,
409 .ndo_start_xmit = sll_xmit,
412 static void sll_setup(struct net_device *dev)
414 dev->netdev_ops = &sll_netdev_ops;
415 dev->destructor = sll_free_netdev;
417 dev->hard_header_len = 0;
419 dev->tx_queue_len = 10;
421 dev->mtu = sizeof(struct can_frame);
422 dev->type = ARPHRD_CAN;
424 /* New-style flags. */
425 dev->flags = IFF_NOARP;
426 dev->features = NETIF_F_NO_CSUM;
429 /******************************************
430 Routines looking at TTY side.
431 ******************************************/
434 * Handle the 'receiver data ready' interrupt.
435 * This function is called by the 'tty_io' module in the kernel when
436 * a block of SLLIN data has been received, which can now be decapsulated
437 * and sent on to some IP layer for further processing. This will not
438 * be re-entered while running but other ldisc functions may be called
442 static void sllin_receive_buf(struct tty_struct *tty,
443 const unsigned char *cp, char *fp, int count)
445 struct sllin *sl = (struct sllin *) tty->disc_data;
447 printk(KERN_INFO "sllin_receive_buf invoked\n");
449 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
452 /* Read the characters out of the buffer */
455 if (!test_and_set_bit(SLF_ERROR, &sl->flags))
456 sl->dev->stats.rx_errors++;
457 printk(KERN_INFO "sllin_receive_buf char 0x%02x ignored "
458 "due marker 0x%02x, flags 0x%lx\n",
459 *cp, *(fp-1), sl->flags);
464 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
465 #ifndef BREAK_BY_BAUD
466 /* We didn't receive Break character */
467 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
468 sl->rx_buff[sl->rx_cnt++] = 0x00;
471 printk(KERN_INFO "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
472 sl->rx_buff[sl->rx_cnt++] = *cp++;
476 if (sl->rx_cnt >= sl->rx_expect) {
477 set_bit(SLF_RXEVENT, &sl->flags);
478 wake_up(&sl->kwt_wq);
479 printk(KERN_INFO "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
481 printk(KERN_INFO "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
485 /*****************************************
486 * sllin message helper routines
487 *****************************************/
489 int sllin_setup_msg(struct sllin *sl, int mode, int id,
490 unsigned char *data, int len)
498 sl->rx_lim = SLLIN_BUFF_LEN;
500 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
501 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
502 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
503 sl->tx_lim = SLLIN_BUFF_DATA;
505 if ((data != NULL) && len) {
510 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
511 /* compute data parity there */
512 for (i = SLLIN_BUFF_DATA; i < sl->tx_lim; i++) {
513 csum += sl->tx_buff[i];
518 sl->tx_buff[sl->tx_lim++] = csum;
521 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
527 int sllin_send_tx_buff(struct sllin *sl)
529 struct tty_struct *tty = sl->tty;
534 if (sl->lin_state != SLSTATE_BREAK_SENT)
535 remains = sl->tx_lim - sl->tx_cnt;
539 remains = sl->tx_lim - sl->tx_cnt;
542 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
550 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
551 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
553 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
561 printk(KERN_INFO "sllin_send_tx_buff sent %d, remains %d\n",
562 sl->tx_cnt, remains);
568 int sllin_send_break(struct sllin *sl)
570 struct tty_struct *tty = sl->tty;
571 unsigned long break_baud;
574 break_baud = ((sl->lin_baud * 2) / 3);
575 sltty_change_speed(tty, break_baud);
577 tty->ops->flush_buffer(tty);
578 sl->rx_cnt = SLLIN_BUFF_BREAK;
580 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
581 sl->lin_state = SLSTATE_BREAK_SENT;
583 res = sllin_send_tx_buff(sl);
585 sl->lin_state = SLSTATE_IDLE;
591 #else /* BREAK_BY_BAUD */
593 int sllin_send_break(struct sllin *sl)
595 struct tty_struct *tty = sl->tty;
596 unsigned long break_baud;
600 sl->rx_cnt = SLLIN_BUFF_BREAK;
601 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
602 sl->lin_state = SLSTATE_BREAK_SENT;
604 /* Do the break ourselves; Inspired by
605 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
606 retval = tty->ops->break_ctl(tty, -1);
611 usleep_range(650, 750);
613 retval = tty->ops->break_ctl(tty, 0);
614 usleep_range(50, 100);
616 tty->ops->flush_buffer(tty);
618 sl->tx_cnt = SLLIN_BUFF_SYNC;
620 printk(KERN_INFO "sllin: Break sent.\n");
621 set_bit(SLF_RXEVENT, &sl->flags);
622 wake_up(&sl->kwt_wq);
626 #endif /* BREAK_BY_BAUD */
628 /*****************************************
629 * sllin_kwthread - kernel worker thread
630 *****************************************/
632 int sllin_kwthread(void *ptr)
634 struct sllin *sl = (struct sllin *)ptr;
635 struct tty_struct *tty = sl->tty;
636 struct sched_param schparam = { .sched_priority = 40 };
638 struct can_frame *cf;
640 printk(KERN_INFO "sllin: sllin_kwthread started.\n");
641 sched_setscheduler(current, SCHED_FIFO, &schparam);
643 clear_bit(SLF_ERROR, &sl->flags);
644 sltty_change_speed(tty, sl->lin_baud);
646 while (!kthread_should_stop()) {
647 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
649 if(sllin_send_break(sl) < 0) {
650 /* error processing */
654 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
655 test_bit(SLF_RXEVENT, &sl->flags) ||
656 test_bit(SLF_TXEVENT, &sl->flags) ||
657 ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)));
659 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
660 printk(KERN_INFO "sllin_kthread RXEVENT \n");
663 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
664 printk(KERN_INFO "sllin_kthread TXEVENT \n");
667 if ((sl->lin_state == SLSTATE_IDLE) && test_bit(SLF_MSGEVENT, &sl->flags)) {
668 cf = (struct can_frame *)sl->rec_skb->data;
670 /* We do care only about SFF frames */
671 if (cf->can_id & CAN_EFF_FLAG)
674 if (cf->can_id & CAN_RTR_FLAG) {
675 printk(KERN_INFO "%s: RTR CAN frame, ID = %x\n",
676 __FUNCTION__, cf->can_id & CAN_SFF_MASK);
677 if (sllin_setup_msg(sl, 0,
678 cf->can_id & CAN_SFF_MASK, NULL, 0) != -1) {
679 sl->id_to_send = true;
680 sl->data_to_send = false;
683 printk(KERN_INFO "%s: NON-RTR CAN frame, ID = %x\n",
684 __FUNCTION__, (int)cf->can_id & CAN_SFF_MASK);
686 if (sllin_setup_msg(sl, 0, cf->can_id & CAN_SFF_MASK,
687 cf->data, cf->can_dlc) != -1) {
688 sl->id_to_send = true;
689 sl->data_to_send = true;
694 clear_bit(SLF_MSGEVENT, &sl->flags);
695 kfree_skb(sl->rec_skb);
696 netif_wake_queue(sl->dev);
699 switch (sl->lin_state) {
700 case SLSTATE_BREAK_SENT:
702 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
705 res = sltty_change_speed(tty, sl->lin_baud);
708 sl->lin_state = SLSTATE_ID_SENT;
709 sllin_send_tx_buff(sl);
712 case SLSTATE_ID_SENT:
713 sl->id_to_send = false;
714 if (sl->data_to_send) {
715 sllin_send_tx_buff(sl);
716 sl->lin_state = SLSTATE_RESPONSE_SENT;
717 sl->rx_expect = sl->tx_lim;
718 goto slstate_response_sent;
720 sl->rx_expect = SLLIN_BUFF_DATA + 2;
721 sl->lin_state = SLSTATE_RESPONSE_WAIT;
722 goto slstate_response_wait;
726 case SLSTATE_RESPONSE_WAIT:
727 slstate_response_wait:
728 if (sl->rx_cnt < sl->rx_expect)
731 printk(KERN_INFO "sllin: response received ID %d len %d\n",
732 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
733 // check checksum in sl->rx_buff
734 // send CAN non-RTR frame with data
735 sl->id_to_send = false;
736 sl->lin_state = SLSTATE_IDLE;
739 case SLSTATE_RESPONSE_SENT:
740 slstate_response_sent:
741 if (sl->rx_cnt < sl->tx_lim)
744 printk(KERN_INFO "sllin: response sent ID %d len %d\n",
745 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
747 sl->id_to_send = false;
748 sl->lin_state = SLSTATE_IDLE;
754 /* sll_bump(sl); send packet to the network layer */
756 /* sl->dev->stats.tx_packets++; send frames statistic */
757 /* netif_wake_queue(sl->dev); allow next Tx packet arrival */
761 printk(KERN_INFO "sllin: sllin_kwthread stopped.\n");
767 /************************************
768 * sllin_open helper routines.
769 ************************************/
771 /* Collect hanged up channels */
772 static void sll_sync(void)
775 struct net_device *dev;
778 for (i = 0; i < maxdev; i++) {
783 sl = netdev_priv(dev);
786 if (dev->flags & IFF_UP)
791 /* Find a free SLLIN channel, and link in this `tty' line. */
792 static struct sllin *sll_alloc(dev_t line)
795 struct net_device *dev = NULL;
798 if (sllin_devs == NULL)
799 return NULL; /* Master array missing ! */
801 for (i = 0; i < maxdev; i++) {
808 /* Sorry, too many, all slots in use */
813 sl = netdev_priv(dev);
814 if (test_bit(SLF_INUSE, &sl->flags)) {
815 unregister_netdevice(dev);
817 sllin_devs[i] = NULL;
823 sprintf(name, "sllin%d", i);
825 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
831 sl = netdev_priv(dev);
833 /* Initialize channel control data */
834 sl->magic = SLLIN_MAGIC;
836 spin_lock_init(&sl->lock);
843 * Open the high-level part of the SLLIN channel.
844 * This function is called by the TTY module when the
845 * SLLIN line discipline is called for. Because we are
846 * sure the tty line exists, we only have to link it to
847 * a free SLLIN channel...
849 * Called in process context serialized from other ldisc calls.
852 static int sllin_open(struct tty_struct *tty)
856 pr_debug("sllin: %s() invoked\n", __FUNCTION__);
858 if (!capable(CAP_NET_ADMIN))
861 if (tty->ops->write == NULL)
864 /* RTnetlink lock is misused here to serialize concurrent
865 opens of sllin channels. There are better ways, but it is
870 /* Collect hanged up channels. */
876 /* First make sure we're not already connected. */
877 if (sl && sl->magic == SLLIN_MAGIC)
880 /* OK. Find a free SLLIN channel to use. */
882 sl = sll_alloc(tty_devnum(tty));
888 sl->line = tty_devnum(tty);
890 if (!test_bit(SLF_INUSE, &sl->flags)) {
891 /* Perform the low-level SLLIN initialization. */
892 sl->lin_master = true;
896 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
899 sl->id_to_send = false;
900 sl->data_to_send = false;
902 sl->lin_baud = 19200;
904 sl->lin_state = SLSTATE_IDLE;
906 set_bit(SLF_INUSE, &sl->flags);
908 init_waitqueue_head(&sl->kwt_wq);
909 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
910 if (sl->kwthread == NULL)
913 err = register_netdevice(sl->dev);
915 goto err_free_chan_and_thread;
918 /* Done. We have linked the TTY line to a channel. */
920 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
922 /* TTY layer expects 0 on success */
925 err_free_chan_and_thread:
926 kthread_stop(sl->kwthread);
931 tty->disc_data = NULL;
932 clear_bit(SLF_INUSE, &sl->flags);
937 /* Count references from TTY module */
942 * Close down a SLLIN channel.
943 * This means flushing out any pending queues, and then returning. This
944 * call is serialized against other ldisc functions.
946 * We also use this method for a hangup event.
949 static void sllin_close(struct tty_struct *tty)
951 struct sllin *sl = (struct sllin *) tty->disc_data;
953 /* First make sure we're connected. */
954 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
957 kthread_stop(sl->kwthread);
960 tty->disc_data = NULL;
963 /* Flush network side */
964 unregister_netdev(sl->dev);
965 /* This will complete via sl_free_netdev */
968 static int sllin_hangup(struct tty_struct *tty)
974 /* Perform I/O control on an active SLLIN channel. */
975 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
976 unsigned int cmd, unsigned long arg)
978 struct sllin *sl = (struct sllin *) tty->disc_data;
981 /* First make sure we're connected. */
982 if (!sl || sl->magic != SLLIN_MAGIC)
987 tmp = strlen(sl->dev->name) + 1;
988 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
996 return tty_mode_ioctl(tty, file, cmd, arg);
1000 static struct tty_ldisc_ops sll_ldisc = {
1001 .owner = THIS_MODULE,
1002 .magic = TTY_LDISC_MAGIC,
1005 .close = sllin_close,
1006 .hangup = sllin_hangup,
1007 .ioctl = sllin_ioctl,
1008 .receive_buf = sllin_receive_buf,
1009 .write_wakeup = sllin_write_wakeup,
1012 static int __init sllin_init(void)
1017 maxdev = 4; /* Sanity */
1020 printk(KERN_INFO "sllin: %d dynamic interface channels.\n", maxdev);
1022 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1024 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1028 /* Fill in our line protocol discipline, and register it */
1029 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1031 printk(KERN_ERR "sllin: can't register line discipline\n");
1037 static void __exit sllin_exit(void)
1040 struct net_device *dev;
1042 unsigned long timeout = jiffies + HZ;
1045 if (sllin_devs == NULL)
1048 /* First of all: check for active disciplines and hangup them.
1052 msleep_interruptible(100);
1055 for (i = 0; i < maxdev; i++) {
1056 dev = sllin_devs[i];
1059 sl = netdev_priv(dev);
1060 spin_lock_bh(&sl->lock);
1063 tty_hangup(sl->tty);
1065 spin_unlock_bh(&sl->lock);
1067 } while (busy && time_before(jiffies, timeout));
1069 /* FIXME: hangup is async so we should wait when doing this second
1072 for (i = 0; i < maxdev; i++) {
1073 dev = sllin_devs[i];
1076 sllin_devs[i] = NULL;
1078 sl = netdev_priv(dev);
1080 printk(KERN_ERR "%s: tty discipline still running\n",
1082 /* Intentionally leak the control block. */
1083 dev->destructor = NULL;
1086 unregister_netdev(dev);
1092 i = tty_unregister_ldisc(N_SLLIN);
1094 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1097 module_init(sllin_init);
1098 module_exit(sllin_exit);