2 * sllin.c - serial line LIN interface driver (using tty line discipline)
4 * This file is derived from drivers/net/can/slcan.c
5 * slcan.c Author: Oliver Hartkopp <socketcan@hartkopp.net>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
17 * You should have received a copy of the GNU General Public License along
18 * with this program; if not, write to the Free Software Foundation, Inc.,
19 * 59 Temple Place, Suite 330, Boston, MA 02111-1307. You can also get it
20 * at http://www.gnu.org/licenses/gpl.html
22 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
25 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
26 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
27 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
28 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
32 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
35 * Idea: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
36 * Copyright: (c) 2011 Czech Technical University in Prague
37 * (c) 2011 Volkswagen Group Research
38 * Authors: Pavel Pisa <pisa@cmp.felk.cvut.cz>
39 * Rostislav Lisovy <lisovy@kormus.cz>
40 * Michal Sojka <sojkam1@fel.cvut.cz>
41 * Funded by: Volkswagen Group Research
44 #define DEBUG 1 /* Enables pr_debug() printouts */
46 #include <linux/module.h>
47 #include <linux/moduleparam.h>
49 #include <asm/system.h>
50 #include <linux/uaccess.h>
51 #include <linux/bitops.h>
52 #include <linux/string.h>
53 #include <linux/tty.h>
54 #include <linux/errno.h>
55 #include <linux/netdevice.h>
56 #include <linux/skbuff.h>
57 #include <linux/rtnetlink.h>
58 #include <linux/if_arp.h>
59 #include <linux/if_ether.h>
60 #include <linux/sched.h>
61 #include <linux/delay.h>
62 #include <linux/init.h>
63 #include <linux/can.h>
64 #include <linux/kthread.h>
65 #include <linux/hrtimer.h>
66 #include "linux/lin_bus.h"
68 /* Should be in include/linux/tty.h */
70 /* -------------------------------- */
72 static __initdata const char banner[] =
73 KERN_INFO "sllin: serial line LIN interface driver\n";
75 MODULE_ALIAS_LDISC(N_SLLIN);
76 MODULE_DESCRIPTION("serial line LIN interface");
77 MODULE_LICENSE("GPL");
78 MODULE_AUTHOR("Pavel Pisa <pisa@cmp.felk.cvut.cz>");
80 #define SLLIN_MAGIC 0x53CA
81 /* #define BREAK_BY_BAUD */
83 static int master = true;
84 static int baudrate; /* Use LIN_DEFAULT_BAUDRATE when not set */
86 module_param(master, bool, 0);
87 MODULE_PARM_DESC(master, "LIN interface is Master device");
88 module_param(baudrate, int, 0);
89 MODULE_PARM_DESC(baudrate, "Baudrate of LIN interface");
91 static int maxdev = 10; /* MAX number of SLLIN channels;
92 This can be overridden with
93 insmod sllin.ko maxdev=nnn */
94 module_param(maxdev, int, 0);
95 MODULE_PARM_DESC(maxdev, "Maximum number of sllin interfaces");
97 /* maximum buffer len to store whole LIN message*/
98 #define SLLIN_DATA_MAX 8
99 #define SLLIN_BUFF_LEN (1 /*break*/ + 1 /*sync*/ + 1 /*ID*/ + \
100 SLLIN_DATA_MAX + 1 /*checksum*/)
101 #define SLLIN_BUFF_BREAK 0
102 #define SLLIN_BUFF_SYNC 1
103 #define SLLIN_BUFF_ID 2
104 #define SLLIN_BUFF_DATA 3
106 #define SLLIN_SAMPLES_PER_CHAR 10
107 #define SLLIN_CHARS_TO_TIMEOUT 24
113 SLSTATE_RESPONSE_WAIT, /* Wait for response */
114 SLSTATE_RESPONSE_WAIT_BUS, /* Wait for response from LIN bus
115 only (CAN frames from network stack
116 are not processed in this moment) */
117 SLSTATE_RESPONSE_SENT,
120 struct sllin_conf_entry {
121 int dlc; /* Length of data in LIN frame */
122 canid_t frame_fl; /* LIN frame flags. Passed from userspace as
124 u8 data[8]; /* LIN frame data payload */
130 /* Various fields. */
131 struct tty_struct *tty; /* ptr to TTY structure */
132 struct net_device *dev; /* easy for intr handling */
135 /* LIN message buffer and actual processed data counts */
136 unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
137 unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
138 int rx_expect; /* expected number of Rx chars */
139 int rx_lim; /* maximum Rx chars for current frame */
140 int rx_cnt; /* message buffer Rx fill level */
141 int tx_lim; /* actual limit of bytes to Tx */
142 int tx_cnt; /* number of already Tx bytes */
143 char lin_master; /* node is a master node */
144 int lin_baud; /* LIN baudrate */
145 int lin_state; /* state */
146 char id_to_send; /* there is ID to be sent */
147 char data_to_send; /* there are data to be sent */
148 char resp_len_known; /* Length of the response is known */
149 char header_received;/* In Slave mode, set when header was already
151 char rx_len_unknown; /* We are not sure how much data will be sent to us --
152 we just guess the length */
154 unsigned long flags; /* Flag values/ mode etc */
155 #define SLF_INUSE 0 /* Channel in use */
156 #define SLF_ERROR 1 /* Parity, etc. error */
157 #define SLF_RXEVENT 2 /* Rx wake event */
158 #define SLF_TXEVENT 3 /* Tx wake event */
159 #define SLF_MSGEVENT 4 /* CAN message to sent */
160 #define SLF_TMOUTEVENT 5 /* Timeout on received data */
161 #define SLF_TXBUFF_RQ 6 /* Req. to send buffer to UART*/
162 #define SLF_TXBUFF_INPR 7 /* Above request in progress */
165 struct task_struct *kwthread;
166 wait_queue_head_t kwt_wq; /* Wait queue used by kwthread */
167 struct hrtimer rx_timer; /* RX timeout timer */
168 ktime_t rx_timer_timeout; /* RX timeout timer value */
169 struct sk_buff *tx_req_skb; /* Socket buffer with CAN frame
170 received from network stack*/
172 /* List with configurations for each of 0 to LIN_ID_MAX LIN IDs */
173 struct sllin_conf_entry linfr_cache[LIN_ID_MAX + 1];
174 spinlock_t linfr_lock; /* frame cache and buffers lock */
177 static struct net_device **sllin_devs;
178 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf);
179 static void sllin_slave_receive_buf(struct tty_struct *tty,
180 const unsigned char *cp, char *fp, int count);
181 static void sllin_master_receive_buf(struct tty_struct *tty,
182 const unsigned char *cp, char *fp, int count);
185 /* Values of two parity bits in LIN Protected
186 Identifier for each particular LIN ID */
187 const unsigned char sllin_id_parity_table[] = {
188 0x80, 0xc0, 0x40, 0x00, 0xc0, 0x80, 0x00, 0x40,
189 0x00, 0x40, 0xc0, 0x80, 0x40, 0x00, 0x80, 0xc0,
190 0x40, 0x00, 0x80, 0xc0, 0x00, 0x40, 0xc0, 0x80,
191 0xc0, 0x80, 0x00, 0x40, 0x80, 0xc0, 0x40, 0x00,
192 0x00, 0x40, 0xc0, 0x80, 0x40, 0x00, 0x80, 0xc0,
193 0x80, 0xc0, 0x40, 0x00, 0xc0, 0x80, 0x00, 0x40,
194 0xc0, 0x80, 0x00, 0x40, 0x80, 0xc0, 0x40, 0x00,
195 0x40, 0x00, 0x80, 0xc0, 0x00, 0x40, 0xc0, 0x80
199 * sltty_change_speed() -- Change baudrate of Serial device belonging
202 * @tty: Pointer to TTY to change speed for.
203 * @speed: Integer value of new speed. It is possible to
204 * assign non-standard values, i.e. those which
205 * are not defined in termbits.h.
207 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
209 struct ktermios old_termios;
212 mutex_lock(&tty->termios_mutex);
214 old_termios = *(tty->termios);
216 cflag = CS8 | CREAD | CLOCAL | HUPCL;
217 cflag &= ~(CBAUD | CIBAUD);
219 tty->termios->c_cflag = cflag;
220 tty->termios->c_oflag = 0;
221 tty->termios->c_lflag = 0;
223 /* Enable interrupt when UART-Break or Framing error received */
224 tty->termios->c_iflag = BRKINT | INPCK;
226 tty_encode_baud_rate(tty, speed, speed);
228 if (tty->ops->set_termios)
229 tty->ops->set_termios(tty, &old_termios);
231 mutex_unlock(&tty->termios_mutex);
236 /* Send one can_frame to the network layer */
237 static void sllin_send_canfr(struct sllin *sl, canid_t id, char *data, int len)
245 memcpy(&cf.data, data, cf.can_dlc);
247 skb = dev_alloc_skb(sizeof(struct can_frame));
252 skb->protocol = htons(ETH_P_CAN);
253 skb->pkt_type = PACKET_BROADCAST;
254 skb->ip_summed = CHECKSUM_UNNECESSARY;
255 memcpy(skb_put(skb, sizeof(struct can_frame)),
256 &cf, sizeof(struct can_frame));
259 sl->dev->stats.rx_packets++;
260 sl->dev->stats.rx_bytes += cf.can_dlc;
264 * sll_bump() -- Send data of received LIN frame (existing in sl->rx_buff)
269 static void sll_bump(struct sllin *sl)
271 int len = sl->rx_cnt - SLLIN_BUFF_DATA - 1; /* without checksum */
272 len = (len < 0) ? 0 : len;
274 sllin_send_canfr(sl, sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK,
275 sl->rx_buff + SLLIN_BUFF_DATA, len);
278 static void sll_send_rtr(struct sllin *sl)
280 sllin_send_canfr(sl, (sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK) |
281 CAN_RTR_FLAG, NULL, 0);
285 * Called by the driver when there's room for more data. If we have
286 * more packets to send, we send them here.
288 static void sllin_write_wakeup(struct tty_struct *tty)
292 struct sllin *sl = (struct sllin *) tty->disc_data;
294 /* First make sure we're connected. */
295 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
298 set_bit(SLF_TXBUFF_RQ, &sl->flags);
300 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
301 return; /* ongoing concurrent processing */
303 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
304 smp_mb__after_clear_bit();
306 if (sl->lin_state != SLSTATE_BREAK_SENT)
307 remains = sl->tx_lim - sl->tx_cnt;
309 remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
312 actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt,
313 sl->tx_cnt - sl->tx_lim);
314 sl->tx_cnt += actual;
317 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
318 smp_mb__after_clear_bit();
320 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
322 if ((remains > 0) && (actual >= 0)) {
323 pr_debug("sllin: sllin_write_wakeup sent %d, "
324 "remains %d, waiting\n",
325 sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
329 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
330 set_bit(SLF_TXEVENT, &sl->flags);
331 wake_up(&sl->kwt_wq);
333 pr_debug("sllin: sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
337 * sll_xmit() -- Send a can_frame to a TTY queue.
339 * @skb: Pointer to Socket buffer to be sent.
340 * @dev: Network device where @skb will be sent.
342 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
344 struct sllin *sl = netdev_priv(dev);
345 struct can_frame *cf;
347 if (skb->len != sizeof(struct can_frame))
350 spin_lock(&sl->lock);
351 if (!netif_running(dev)) {
352 printk(KERN_WARNING "%s: xmit: iface is down\n", dev->name);
355 if (sl->tty == NULL) {
356 printk(KERN_WARNING "%s: xmit: no tty device connected\n", dev->name);
360 cf = (struct can_frame *) skb->data;
361 if (cf->can_id & LIN_CTRL_FRAME) {
362 sllin_configure_frame_cache(sl, cf);
363 goto free_out_unlock;
366 netif_stop_queue(sl->dev);
368 sl->tx_req_skb = skb;
369 set_bit(SLF_MSGEVENT, &sl->flags);
370 wake_up(&sl->kwt_wq);
371 spin_unlock(&sl->lock);
376 spin_unlock(&sl->lock);
383 /******************************************
384 * Routines looking at netdevice side.
385 ******************************************/
387 /* Netdevice UP -> DOWN routine */
388 static int sll_close(struct net_device *dev)
390 struct sllin *sl = netdev_priv(dev);
392 spin_lock_bh(&sl->lock);
394 /* TTY discipline is running. */
395 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
397 netif_stop_queue(dev);
400 spin_unlock_bh(&sl->lock);
405 /* Netdevice DOWN -> UP routine */
406 static int sll_open(struct net_device *dev)
408 struct sllin *sl = netdev_priv(dev);
410 pr_debug("sllin: %s() invoked\n", __func__);
415 sl->flags &= (1 << SLF_INUSE);
416 netif_start_queue(dev);
420 /* Hook the destructor so we can free sllin devs at the right point in time */
421 static void sll_free_netdev(struct net_device *dev)
423 int i = dev->base_addr;
425 sllin_devs[i] = NULL;
428 static const struct net_device_ops sll_netdev_ops = {
429 .ndo_open = sll_open,
430 .ndo_stop = sll_close,
431 .ndo_start_xmit = sll_xmit,
434 static void sll_setup(struct net_device *dev)
436 dev->netdev_ops = &sll_netdev_ops;
437 dev->destructor = sll_free_netdev;
439 dev->hard_header_len = 0;
441 dev->tx_queue_len = 10;
443 dev->mtu = sizeof(struct can_frame);
444 dev->type = ARPHRD_CAN;
446 /* New-style flags. */
447 dev->flags = IFF_NOARP;
448 dev->features = NETIF_F_NO_CSUM;
451 /******************************************
452 Routines looking at TTY side.
453 ******************************************/
454 static void sllin_master_receive_buf(struct tty_struct *tty,
455 const unsigned char *cp, char *fp, int count)
457 struct sllin *sl = (struct sllin *) tty->disc_data;
459 /* Read the characters out of the buffer */
462 pr_debug("sllin: sllin_receive_buf char 0x%02x ignored "
463 "due marker 0x%02x, flags 0x%lx\n",
464 *cp, *(fp-1), sl->flags);
466 /* i.e. Real error -- not Break */
467 if (sl->rx_cnt > SLLIN_BUFF_BREAK) {
468 set_bit(SLF_ERROR, &sl->flags);
469 wake_up(&sl->kwt_wq);
474 #ifndef BREAK_BY_BAUD
475 /* We didn't receive Break character -- fake it! */
476 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
477 pr_debug("sllin: LIN_RX[%d]: 0x00\n", sl->rx_cnt);
478 sl->rx_buff[sl->rx_cnt++] = 0x00;
480 #endif /* BREAK_BY_BAUD */
482 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
483 pr_debug("sllin: LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
484 sl->rx_buff[sl->rx_cnt++] = *cp++;
489 if (sl->rx_cnt >= sl->rx_expect) {
490 set_bit(SLF_RXEVENT, &sl->flags);
491 wake_up(&sl->kwt_wq);
492 pr_debug("sllin: sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
494 pr_debug("sllin: sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
499 static void sllin_slave_receive_buf(struct tty_struct *tty,
500 const unsigned char *cp, char *fp, int count)
502 struct sllin *sl = (struct sllin *) tty->disc_data;
504 struct sllin_conf_entry *sce;
507 /* Read the characters out of the buffer */
510 pr_debug("sllin: sllin_receive_buf char 0x%02x ignored "
511 "due marker 0x%02x, flags 0x%lx\n",
512 *cp, *(fp-1), sl->flags);
516 sl->rx_expect = SLLIN_BUFF_ID + 1;
517 sl->rx_len_unknown = false; /* We do know exact length of the header */
518 sl->header_received = false;
519 //sl->rx_buff[sl->rx_cnt++] = 0x00;
522 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
523 pr_debug("sllin: LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
524 sl->rx_buff[sl->rx_cnt++] = *cp++;
527 /* Header received */
528 if ((sl->header_received == false) && (sl->rx_cnt >= (SLLIN_BUFF_ID + 1))) {
531 lin_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
532 sce = &sl->linfr_cache[lin_id];
534 spin_lock_irqsave(&sl->linfr_lock, flags);
535 /* Is the length of data set in frame cache? */
536 if (sce->frame_fl & LIN_LOC_SLAVE_CACHE) {
537 sl->rx_expect += sce->dlc;
538 sl->rx_len_unknown = false;
540 sl->rx_expect += SLLIN_DATA_MAX + 1; /* + checksum */
541 sl->rx_len_unknown = true;
543 spin_unlock_irqrestore(&sl->linfr_lock, flags);
545 sl->header_received = true;
550 /* Response received */
551 if ((sl->header_received == true) &&
552 ((sl->rx_cnt >= sl->rx_expect) ||
553 ((sl->rx_len_unknown == true) && (count == 0)))) {
556 pr_debug("sllin: Received LIN header & LIN response. "
557 "rx_cnt = %u, rx_expect = %u\n", sl->rx_cnt,
560 /* Prepare for reception of new header */
562 sl->rx_expect = SLLIN_BUFF_ID + 1;
563 sl->rx_len_unknown = false; /* We do know exact length of the header */
564 sl->header_received = false;
569 static void sllin_receive_buf(struct tty_struct *tty,
570 const unsigned char *cp, char *fp, int count)
572 struct sllin *sl = (struct sllin *) tty->disc_data;
573 pr_debug("sllin: sllin_receive_buf invoked, count = %u\n", count);
575 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
579 sllin_master_receive_buf(tty, cp, fp, count);
581 sllin_slave_receive_buf(tty, cp, fp, count);
585 /*****************************************
586 * sllin message helper routines
587 *****************************************/
589 * sllin_report_error() -- Report an error by sending CAN frame
590 * with particular error flag set in can_id
593 * @err: Error flag to be sent.
595 void sllin_report_error(struct sllin *sl, int err)
598 case LIN_ERR_CHECKSUM:
599 sl->dev->stats.rx_crc_errors++;
602 case LIN_ERR_RX_TIMEOUT:
603 sl->dev->stats.rx_errors++;
606 case LIN_ERR_FRAMING:
607 sl->dev->stats.rx_frame_errors++;
611 sllin_send_canfr(sl, 0 | CAN_EFF_FLAG |
612 (err & ~LIN_ID_MASK), NULL, 0);
616 * sllin_configure_frame_cache() -- Configure particular entry in linfr_cache
619 * @cf: Pointer to CAN frame sent to this driver
620 * holding configuration information
622 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf)
625 struct sllin_conf_entry *sce;
627 if (!(cf->can_id & LIN_ID_CONF))
630 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
631 pr_debug("sllin: Setting frame cache with EFF CAN frame. "
632 "LIN ID = %d\n", cf->can_id & LIN_ID_MASK);
634 spin_lock_irqsave(&sl->linfr_lock, flags);
636 sce->dlc = cf->can_dlc;
637 if (sce->dlc > SLLIN_DATA_MAX)
638 sce->dlc = SLLIN_DATA_MAX;
640 sce->frame_fl = (cf->can_id & ~LIN_ID_MASK) & CAN_EFF_MASK;
641 memcpy(sce->data, cf->data, cf->can_dlc);
643 spin_unlock_irqrestore(&sl->linfr_lock, flags);
649 * sllin_checksum() -- Count checksum for particular data
651 * @data: Pointer to the buffer containing whole LIN
652 * frame (i.e. including break and sync bytes).
653 * @length: Length of the buffer.
654 * @enhanced_fl: Flag determining whether Enhanced or Classic
655 * checksum should be counted.
657 static inline unsigned sllin_checksum(unsigned char *data, int length, int enhanced_fl)
667 for (; i < length; i++) {
676 #define SLLIN_STPMSG_RESPONLY (1) /* Message will be LIN Response only */
677 #define SLLIN_STPMSG_CHCKSUM_CLS (1 << 1)
678 #define SLLIN_STPMSG_CHCKSUM_ENH (1 << 2)
680 int sllin_setup_msg(struct sllin *sl, int mode, int id,
681 unsigned char *data, int len)
683 if (id > LIN_ID_MASK)
686 if (!(mode & SLLIN_STPMSG_RESPONLY)) {
690 sl->rx_lim = SLLIN_BUFF_LEN;
693 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
694 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
695 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
696 sl->tx_lim = SLLIN_BUFF_DATA;
698 if ((data != NULL) && len) {
700 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
701 sl->tx_buff[sl->tx_lim++] = sllin_checksum(sl->tx_buff,
702 sl->tx_lim, mode & SLLIN_STPMSG_CHCKSUM_ENH);
705 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
710 static void sllin_reset_buffs(struct sllin *sl)
714 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
717 sl->id_to_send = false;
718 sl->data_to_send = false;
721 int sllin_send_tx_buff(struct sllin *sl)
723 struct tty_struct *tty = sl->tty;
727 set_bit(SLF_TXBUFF_RQ, &sl->flags);
729 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
730 return 0; /* ongoing concurrent processing */
732 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
733 smp_mb__after_clear_bit();
736 if (sl->lin_state != SLSTATE_BREAK_SENT)
737 remains = sl->tx_lim - sl->tx_cnt;
741 remains = sl->tx_lim - sl->tx_cnt;
744 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
752 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
753 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
755 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
763 pr_debug("sllin: sllin_send_tx_buff sent %d, remains %d\n",
764 sl->tx_cnt, remains);
766 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
767 smp_mb__after_clear_bit();
769 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
774 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
780 int sllin_send_break(struct sllin *sl)
782 struct tty_struct *tty = sl->tty;
783 unsigned long break_baud;
786 break_baud = ((sl->lin_baud * 2) / 3);
787 sltty_change_speed(tty, break_baud);
789 tty->ops->flush_buffer(tty);
790 sl->rx_cnt = SLLIN_BUFF_BREAK;
792 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
793 sl->lin_state = SLSTATE_BREAK_SENT;
795 res = sllin_send_tx_buff(sl);
797 sl->lin_state = SLSTATE_IDLE;
803 #else /* BREAK_BY_BAUD */
805 int sllin_send_break(struct sllin *sl)
807 struct tty_struct *tty = sl->tty;
809 unsigned long break_baud;
810 unsigned long usleep_range_min;
811 unsigned long usleep_range_max;
813 break_baud = ((sl->lin_baud * 2) / 3);
814 sl->rx_cnt = SLLIN_BUFF_BREAK;
815 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
816 sl->lin_state = SLSTATE_BREAK_SENT;
818 /* Do the break ourselves; Inspired by
819 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
820 retval = tty->ops->break_ctl(tty, -1);
825 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR) / break_baud;
826 usleep_range_max = usleep_range_min + 50;
827 usleep_range(usleep_range_min, usleep_range_max);
829 retval = tty->ops->break_ctl(tty, 0);
830 usleep_range_min = (1000000l * 1 /* 1 bit */) / break_baud;
831 usleep_range_max = usleep_range_min + 30;
832 usleep_range(usleep_range_min, usleep_range_max);
834 tty->ops->flush_buffer(tty);
836 sl->tx_cnt = SLLIN_BUFF_SYNC;
838 pr_debug("sllin: Break sent.\n");
839 set_bit(SLF_RXEVENT, &sl->flags);
840 wake_up(&sl->kwt_wq);
844 #endif /* BREAK_BY_BAUD */
847 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
849 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
851 sllin_report_error(sl, LIN_ERR_RX_TIMEOUT);
852 set_bit(SLF_TMOUTEVENT, &sl->flags);
853 wake_up(&sl->kwt_wq);
855 return HRTIMER_NORESTART;
859 * sllin_rx_validate() -- Validate received frame, i,e. check checksum
863 static int sllin_rx_validate(struct sllin *sl)
869 unsigned char rec_chcksm = sl->rx_buff[sl->rx_cnt - 1];
870 struct sllin_conf_entry *sce;
872 actual_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
873 sce = &sl->linfr_cache[actual_id];
875 spin_lock_irqsave(&sl->linfr_lock, flags);
877 ext_chcks_fl = sce->frame_fl & LIN_CHECKSUM_EXTENDED;
878 spin_unlock_irqrestore(&sl->linfr_lock, flags);
880 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) !=
883 /* Type of checksum is configured for particular frame */
887 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1,
888 !ext_chcks_fl) != rec_chcksm) {
897 /*****************************************
898 * sllin_kwthread - kernel worker thread
899 *****************************************/
901 int sllin_kwthread(void *ptr)
903 struct sllin *sl = (struct sllin *)ptr;
904 struct tty_struct *tty = sl->tty;
905 struct sched_param schparam = { .sched_priority = 40 };
906 int tx_bytes = 0; /* Used for Network statistics */
909 pr_debug("sllin: sllin_kwthread started.\n");
910 sched_setscheduler(current, SCHED_FIFO, &schparam);
912 clear_bit(SLF_ERROR, &sl->flags);
913 sltty_change_speed(tty, sl->lin_baud);
915 while (!kthread_should_stop()) {
916 struct can_frame *cf;
919 u8 lin_data_buff[SLLIN_DATA_MAX];
922 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
924 if (sllin_send_break(sl) < 0) {
925 /* error processing */
929 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
930 test_bit(SLF_RXEVENT, &sl->flags) ||
931 test_bit(SLF_TXEVENT, &sl->flags) ||
932 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
933 test_bit(SLF_ERROR, &sl->flags) ||
934 (((sl->lin_state == SLSTATE_IDLE) ||
935 (sl->lin_state == SLSTATE_RESPONSE_WAIT))
936 && test_bit(SLF_MSGEVENT, &sl->flags)));
938 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
939 pr_debug("sllin: sllin_kthread RXEVENT\n");
942 if (test_and_clear_bit(SLF_ERROR, &sl->flags)) {
943 unsigned long usleep_range_min;
944 unsigned long usleep_range_max;
945 hrtimer_cancel(&sl->rx_timer);
946 pr_debug("sllin: sllin_kthread ERROR\n");
948 if (sl->lin_state != SLSTATE_IDLE)
949 sllin_report_error(sl, LIN_ERR_FRAMING);
951 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR * 10) /
953 usleep_range_max = usleep_range_min + 50;
954 usleep_range(usleep_range_min, usleep_range_max);
955 sllin_reset_buffs(sl);
956 sl->lin_state = SLSTATE_IDLE;
959 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
960 pr_debug("sllin: sllin_kthread TXEVENT\n");
963 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
964 pr_debug("sllin: sllin_kthread TMOUTEVENT\n");
965 sllin_reset_buffs(sl);
967 sl->lin_state = SLSTATE_IDLE;
970 switch (sl->lin_state) {
972 if (!test_bit(SLF_MSGEVENT, &sl->flags))
975 cf = (struct can_frame *)sl->tx_req_skb->data;
977 /* SFF RTR CAN frame -> LIN header */
978 if (cf->can_id & CAN_RTR_FLAG) {
980 struct sllin_conf_entry *sce;
982 pr_debug("sllin: %s: RTR SFF CAN frame, ID = %x\n",
983 __func__, cf->can_id & LIN_ID_MASK);
985 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
986 spin_lock_irqsave(&sl->linfr_lock, flags);
988 /* Is there Slave response in linfr_cache to be sent? */
989 if ((sce->frame_fl & LIN_LOC_SLAVE_CACHE)
992 pr_debug("sllin: Sending LIN response from linfr_cache\n");
994 lin_data = sce->data;
996 if (lin_dlc > SLLIN_DATA_MAX)
997 lin_dlc = SLLIN_DATA_MAX;
998 memcpy(lin_data_buff, lin_data, lin_dlc);
999 lin_data = lin_data_buff;
1004 spin_unlock_irqrestore(&sl->linfr_lock, flags);
1006 } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
1007 pr_debug("sllin: %s: NON-RTR SFF CAN frame, ID = %x\n",
1008 __func__, (int)cf->can_id & LIN_ID_MASK);
1010 lin_data = cf->data;
1011 lin_dlc = cf->can_dlc;
1012 if (lin_dlc > SLLIN_DATA_MAX)
1013 lin_dlc = SLLIN_DATA_MAX;
1017 if (sllin_setup_msg(sl, 0, cf->can_id & LIN_ID_MASK,
1018 lin_data, lin_dlc) != -1) {
1020 sl->id_to_send = true;
1021 sl->data_to_send = (lin_data != NULL) ? true : false;
1022 sl->resp_len_known = (lin_dlc > 0) ? true : false;
1023 sl->dev->stats.tx_packets++;
1024 sl->dev->stats.tx_bytes += tx_bytes;
1027 clear_bit(SLF_MSGEVENT, &sl->flags);
1028 kfree_skb(sl->tx_req_skb);
1029 netif_wake_queue(sl->dev);
1030 hrtimer_start(&sl->rx_timer,
1031 ktime_add(ktime_get(), sl->rx_timer_timeout),
1035 case SLSTATE_BREAK_SENT:
1036 #ifdef BREAK_BY_BAUD
1037 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
1040 res = sltty_change_speed(tty, sl->lin_baud);
1043 sl->lin_state = SLSTATE_ID_SENT;
1044 sllin_send_tx_buff(sl);
1047 case SLSTATE_ID_SENT:
1048 hrtimer_cancel(&sl->rx_timer);
1049 sl->id_to_send = false;
1050 if (sl->data_to_send) {
1051 sllin_send_tx_buff(sl);
1052 sl->lin_state = SLSTATE_RESPONSE_SENT;
1053 sl->rx_expect = sl->tx_lim;
1054 goto slstate_response_sent;
1056 if (sl->resp_len_known) {
1057 sl->rx_expect = sl->rx_lim;
1059 sl->rx_expect = SLLIN_BUFF_DATA + 2;
1061 sl->lin_state = SLSTATE_RESPONSE_WAIT;
1062 /* If we don't receive anything, timer will "unblock" us */
1063 hrtimer_start(&sl->rx_timer,
1064 ktime_add(ktime_get(), sl->rx_timer_timeout),
1066 goto slstate_response_wait;
1070 case SLSTATE_RESPONSE_WAIT:
1071 slstate_response_wait:
1072 if (test_bit(SLF_MSGEVENT, &sl->flags)) {
1073 unsigned char *lin_buff;
1074 cf = (struct can_frame *)sl->tx_req_skb->data;
1076 lin_buff = (sl->lin_master) ? sl->tx_buff : sl->rx_buff;
1077 if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & LIN_ID_MASK)) {
1078 hrtimer_cancel(&sl->rx_timer);
1079 pr_debug("sllin: received LIN response in a CAN frame.\n");
1080 if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY,
1081 cf->can_id & LIN_ID_MASK,
1082 cf->data, cf->can_dlc) != -1) {
1084 sl->rx_expect = sl->tx_lim;
1085 sl->data_to_send = true;
1086 sl->dev->stats.tx_packets++;
1087 sl->dev->stats.tx_bytes += tx_bytes;
1089 if (!sl->lin_master) {
1090 sl->tx_cnt = SLLIN_BUFF_DATA;
1093 sllin_send_tx_buff(sl);
1094 clear_bit(SLF_MSGEVENT, &sl->flags);
1095 kfree_skb(sl->tx_req_skb);
1096 netif_wake_queue(sl->dev);
1098 sl->lin_state = SLSTATE_RESPONSE_SENT;
1099 goto slstate_response_sent;
1102 sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
1106 /* Be aware, no BREAK here */
1107 case SLSTATE_RESPONSE_WAIT_BUS:
1108 if (sl->rx_cnt < sl->rx_expect)
1111 hrtimer_cancel(&sl->rx_timer);
1112 pr_debug("sllin: response received ID %d len %d\n",
1113 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1115 if (sllin_rx_validate(sl) == -1) {
1116 pr_debug("sllin: RX validation failed.\n");
1117 sllin_report_error(sl, LIN_ERR_CHECKSUM);
1119 /* Send CAN non-RTR frame with data */
1120 pr_debug("sllin: sending NON-RTR CAN"
1121 "frame with LIN payload.");
1122 sll_bump(sl); /* send packet to the network layer */
1125 sl->id_to_send = false;
1126 sl->lin_state = SLSTATE_IDLE;
1129 case SLSTATE_RESPONSE_SENT:
1130 slstate_response_sent:
1131 if (sl->rx_cnt < sl->tx_lim)
1134 hrtimer_cancel(&sl->rx_timer);
1135 sll_bump(sl); /* send packet to the network layer */
1136 pr_debug("sllin: response sent ID %d len %d\n",
1137 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1139 sl->id_to_send = false;
1140 sl->lin_state = SLSTATE_IDLE;
1145 hrtimer_cancel(&sl->rx_timer);
1146 pr_debug("sllin: sllin_kwthread stopped.\n");
1152 /************************************
1153 * sllin_open helper routines.
1154 ************************************/
1156 /* Collect hanged up channels */
1157 static void sll_sync(void)
1160 struct net_device *dev;
1163 for (i = 0; i < maxdev; i++) {
1164 dev = sllin_devs[i];
1168 sl = netdev_priv(dev);
1171 if (dev->flags & IFF_UP)
1176 /* Find a free SLLIN channel, and link in this `tty' line. */
1177 static struct sllin *sll_alloc(dev_t line)
1180 struct net_device *dev = NULL;
1183 if (sllin_devs == NULL)
1184 return NULL; /* Master array missing ! */
1186 for (i = 0; i < maxdev; i++) {
1187 dev = sllin_devs[i];
1193 /* Sorry, too many, all slots in use */
1198 sl = netdev_priv(dev);
1199 if (test_bit(SLF_INUSE, &sl->flags)) {
1200 unregister_netdevice(dev);
1202 sllin_devs[i] = NULL;
1207 char name[IFNAMSIZ];
1208 sprintf(name, "sllin%d", i);
1210 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
1216 sl = netdev_priv(dev);
1217 /* Initialize channel control data */
1218 sl->magic = SLLIN_MAGIC;
1220 spin_lock_init(&sl->lock);
1221 spin_lock_init(&sl->linfr_lock);
1222 sllin_devs[i] = dev;
1228 * Open the high-level part of the SLLIN channel.
1229 * This function is called by the TTY module when the
1230 * SLLIN line discipline is called for. Because we are
1231 * sure the tty line exists, we only have to link it to
1232 * a free SLLIN channel...
1234 * Called in process context serialized from other ldisc calls.
1237 static int sllin_open(struct tty_struct *tty)
1241 pr_debug("sllin: %s() invoked\n", __func__);
1243 if (!capable(CAP_NET_ADMIN))
1246 if (tty->ops->write == NULL)
1249 /* RTnetlink lock is misused here to serialize concurrent
1250 opens of sllin channels. There are better ways, but it is
1255 /* Collect hanged up channels. */
1258 sl = tty->disc_data;
1261 /* First make sure we're not already connected. */
1262 if (sl && sl->magic == SLLIN_MAGIC)
1265 /* OK. Find a free SLLIN channel to use. */
1267 sl = sll_alloc(tty_devnum(tty));
1272 tty->disc_data = sl;
1273 sl->line = tty_devnum(tty);
1275 if (!test_bit(SLF_INUSE, &sl->flags)) {
1276 /* Perform the low-level SLLIN initialization. */
1277 sl->lin_master = master;
1280 pr_debug("sllin: Configured as MASTER\n");
1282 pr_debug("sllin: Configured as SLAVE\n");
1285 sllin_reset_buffs(sl);
1287 sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
1288 pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
1290 sl->lin_state = SLSTATE_IDLE;
1292 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1293 sl->rx_timer.function = sllin_rx_timeout_handler;
1294 /* timeval_to_ktime(msg_head->ival1); */
1295 sl->rx_timer_timeout = ns_to_ktime(
1296 (1000000000l / sl->lin_baud) *
1297 SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT);
1299 set_bit(SLF_INUSE, &sl->flags);
1301 init_waitqueue_head(&sl->kwt_wq);
1302 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
1303 if (sl->kwthread == NULL)
1306 err = register_netdevice(sl->dev);
1308 goto err_free_chan_and_thread;
1311 /* Done. We have linked the TTY line to a channel. */
1313 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
1315 /* TTY layer expects 0 on success */
1318 err_free_chan_and_thread:
1319 kthread_stop(sl->kwthread);
1320 sl->kwthread = NULL;
1324 tty->disc_data = NULL;
1325 clear_bit(SLF_INUSE, &sl->flags);
1330 /* Count references from TTY module */
1335 * Close down a SLLIN channel.
1336 * This means flushing out any pending queues, and then returning. This
1337 * call is serialized against other ldisc functions.
1339 * We also use this method for a hangup event.
1342 static void sllin_close(struct tty_struct *tty)
1344 struct sllin *sl = (struct sllin *) tty->disc_data;
1346 /* First make sure we're connected. */
1347 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
1350 kthread_stop(sl->kwthread);
1351 sl->kwthread = NULL;
1353 tty->disc_data = NULL;
1356 /* Flush network side */
1357 unregister_netdev(sl->dev);
1358 /* This will complete via sl_free_netdev */
1361 static int sllin_hangup(struct tty_struct *tty)
1367 /* Perform I/O control on an active SLLIN channel. */
1368 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
1369 unsigned int cmd, unsigned long arg)
1371 struct sllin *sl = (struct sllin *) tty->disc_data;
1374 /* First make sure we're connected. */
1375 if (!sl || sl->magic != SLLIN_MAGIC)
1380 tmp = strlen(sl->dev->name) + 1;
1381 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1389 return tty_mode_ioctl(tty, file, cmd, arg);
1393 static struct tty_ldisc_ops sll_ldisc = {
1394 .owner = THIS_MODULE,
1395 .magic = TTY_LDISC_MAGIC,
1398 .close = sllin_close,
1399 .hangup = sllin_hangup,
1400 .ioctl = sllin_ioctl,
1401 .receive_buf = sllin_receive_buf,
1402 .write_wakeup = sllin_write_wakeup,
1405 static int __init sllin_init(void)
1410 maxdev = 4; /* Sanity */
1413 pr_debug("sllin: %d dynamic interface channels.\n", maxdev);
1415 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1417 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1421 /* Fill in our line protocol discipline, and register it */
1422 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1424 printk(KERN_ERR "sllin: can't register line discipline\n");
1428 #ifdef BREAK_BY_BAUD
1429 pr_debug("sllin: Break is generated by baud-rate change.");
1431 pr_debug("sllin: Break is generated manually with tiny sleep.");
1437 static void __exit sllin_exit(void)
1440 struct net_device *dev;
1442 unsigned long timeout = jiffies + HZ;
1445 if (sllin_devs == NULL)
1448 /* First of all: check for active disciplines and hangup them.
1452 msleep_interruptible(100);
1455 for (i = 0; i < maxdev; i++) {
1456 dev = sllin_devs[i];
1459 sl = netdev_priv(dev);
1460 spin_lock_bh(&sl->lock);
1463 tty_hangup(sl->tty);
1465 spin_unlock_bh(&sl->lock);
1467 } while (busy && time_before(jiffies, timeout));
1469 /* FIXME: hangup is async so we should wait when doing this second
1472 for (i = 0; i < maxdev; i++) {
1473 dev = sllin_devs[i];
1476 sllin_devs[i] = NULL;
1478 sl = netdev_priv(dev);
1480 printk(KERN_ERR "%s: tty discipline still running\n",
1482 /* Intentionally leak the control block. */
1483 dev->destructor = NULL;
1486 unregister_netdev(dev);
1492 i = tty_unregister_ldisc(N_SLLIN);
1494 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1497 module_init(sllin_init);
1498 module_exit(sllin_exit);