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;
521 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
522 pr_debug("sllin: LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
524 /* We did not receive break (0x00) character */
525 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
526 sl->rx_buff[sl->rx_cnt++] = 0x00;
529 if (sl->rx_cnt == SLLIN_BUFF_SYNC) {
530 /* 'Duplicated' break character -- ignore */
536 /* Wrong sync character */
541 sl->rx_buff[sl->rx_cnt++] = *cp++;
544 /* Header received */
545 if ((sl->header_received == false) && (sl->rx_cnt >= (SLLIN_BUFF_ID + 1))) {
548 lin_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
549 sce = &sl->linfr_cache[lin_id];
551 spin_lock_irqsave(&sl->linfr_lock, flags);
552 /* Is the length of data set in frame cache? */
553 if (sce->frame_fl & LIN_CACHE_RESPONSE) {
554 sl->rx_expect += sce->dlc;
555 sl->rx_len_unknown = false;
557 sl->rx_expect += SLLIN_DATA_MAX + 1; /* + checksum */
558 sl->rx_len_unknown = true;
560 spin_unlock_irqrestore(&sl->linfr_lock, flags);
562 sl->header_received = true;
567 /* Response received */
568 if ((sl->header_received == true) &&
569 ((sl->rx_cnt >= sl->rx_expect) ||
570 ((sl->rx_len_unknown == true) && (count == 0)))) {
573 pr_debug("sllin: Received LIN header & LIN response. "
574 "rx_cnt = %u, rx_expect = %u\n", sl->rx_cnt,
577 /* Prepare for reception of new header */
579 sl->rx_expect = SLLIN_BUFF_ID + 1;
580 sl->rx_len_unknown = false; /* We do know exact length of the header */
581 sl->header_received = false;
586 static void sllin_receive_buf(struct tty_struct *tty,
587 const unsigned char *cp, char *fp, int count)
589 struct sllin *sl = (struct sllin *) tty->disc_data;
590 pr_debug("sllin: sllin_receive_buf invoked, count = %u\n", count);
592 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
596 sllin_master_receive_buf(tty, cp, fp, count);
598 sllin_slave_receive_buf(tty, cp, fp, count);
602 /*****************************************
603 * sllin message helper routines
604 *****************************************/
606 * sllin_report_error() -- Report an error by sending CAN frame
607 * with particular error flag set in can_id
610 * @err: Error flag to be sent.
612 void sllin_report_error(struct sllin *sl, int err)
615 case LIN_ERR_CHECKSUM:
616 sl->dev->stats.rx_crc_errors++;
619 case LIN_ERR_RX_TIMEOUT:
620 sl->dev->stats.rx_errors++;
623 case LIN_ERR_FRAMING:
624 sl->dev->stats.rx_frame_errors++;
628 sllin_send_canfr(sl, 0 | CAN_EFF_FLAG |
629 (err & ~LIN_ID_MASK), NULL, 0);
633 * sllin_configure_frame_cache() -- Configure particular entry in linfr_cache
636 * @cf: Pointer to CAN frame sent to this driver
637 * holding configuration information
639 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf)
642 struct sllin_conf_entry *sce;
644 if (!(cf->can_id & LIN_CTRL_FRAME))
647 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
648 pr_debug("sllin: Setting frame cache with EFF CAN frame. "
649 "LIN ID = %d\n", cf->can_id & LIN_ID_MASK);
651 spin_lock_irqsave(&sl->linfr_lock, flags);
653 sce->dlc = cf->can_dlc;
654 if (sce->dlc > SLLIN_DATA_MAX)
655 sce->dlc = SLLIN_DATA_MAX;
657 sce->frame_fl = (cf->can_id & ~LIN_ID_MASK) & CAN_EFF_MASK;
658 memcpy(sce->data, cf->data, cf->can_dlc);
660 spin_unlock_irqrestore(&sl->linfr_lock, flags);
666 * sllin_checksum() -- Count checksum for particular data
668 * @data: Pointer to the buffer containing whole LIN
669 * frame (i.e. including break and sync bytes).
670 * @length: Length of the buffer.
671 * @enhanced_fl: Flag determining whether Enhanced or Classic
672 * checksum should be counted.
674 static inline unsigned sllin_checksum(unsigned char *data, int length, int enhanced_fl)
684 for (; i < length; i++) {
693 #define SLLIN_STPMSG_RESPONLY (1) /* Message will be LIN Response only */
694 #define SLLIN_STPMSG_CHCKSUM_CLS (1 << 1)
695 #define SLLIN_STPMSG_CHCKSUM_ENH (1 << 2)
697 int sllin_setup_msg(struct sllin *sl, int mode, int id,
698 unsigned char *data, int len)
700 if (id > LIN_ID_MASK)
703 if (!(mode & SLLIN_STPMSG_RESPONLY)) {
707 sl->rx_lim = SLLIN_BUFF_LEN;
710 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
711 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
712 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
713 sl->tx_lim = SLLIN_BUFF_DATA;
715 if ((data != NULL) && len) {
717 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
718 sl->tx_buff[sl->tx_lim] = sllin_checksum(sl->tx_buff,
719 sl->tx_lim, mode & SLLIN_STPMSG_CHCKSUM_ENH);
723 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
728 static void sllin_reset_buffs(struct sllin *sl)
732 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
735 sl->id_to_send = false;
736 sl->data_to_send = false;
739 int sllin_send_tx_buff(struct sllin *sl)
741 struct tty_struct *tty = sl->tty;
745 set_bit(SLF_TXBUFF_RQ, &sl->flags);
747 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
748 return 0; /* ongoing concurrent processing */
750 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
751 smp_mb__after_clear_bit();
754 if (sl->lin_state != SLSTATE_BREAK_SENT)
755 remains = sl->tx_lim - sl->tx_cnt;
759 remains = sl->tx_lim - sl->tx_cnt;
762 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
770 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
771 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
773 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
781 pr_debug("sllin: sllin_send_tx_buff sent %d, remains %d\n",
782 sl->tx_cnt, remains);
784 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
785 smp_mb__after_clear_bit();
787 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
792 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
798 int sllin_send_break(struct sllin *sl)
800 struct tty_struct *tty = sl->tty;
801 unsigned long break_baud;
804 break_baud = ((sl->lin_baud * 2) / 3);
805 sltty_change_speed(tty, break_baud);
807 tty->ops->flush_buffer(tty);
808 sl->rx_cnt = SLLIN_BUFF_BREAK;
810 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
811 sl->lin_state = SLSTATE_BREAK_SENT;
813 res = sllin_send_tx_buff(sl);
815 sl->lin_state = SLSTATE_IDLE;
821 #else /* BREAK_BY_BAUD */
823 int sllin_send_break(struct sllin *sl)
825 struct tty_struct *tty = sl->tty;
827 unsigned long break_baud;
828 unsigned long usleep_range_min;
829 unsigned long usleep_range_max;
831 break_baud = ((sl->lin_baud * 2) / 3);
832 sl->rx_cnt = SLLIN_BUFF_BREAK;
833 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
834 sl->lin_state = SLSTATE_BREAK_SENT;
836 /* Do the break ourselves; Inspired by
837 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
838 retval = tty->ops->break_ctl(tty, -1);
843 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR) / break_baud;
844 usleep_range_max = usleep_range_min + 50;
845 usleep_range(usleep_range_min, usleep_range_max);
847 retval = tty->ops->break_ctl(tty, 0);
848 usleep_range_min = (1000000l * 1 /* 1 bit */) / break_baud;
849 usleep_range_max = usleep_range_min + 30;
850 usleep_range(usleep_range_min, usleep_range_max);
852 tty->ops->flush_buffer(tty);
854 sl->tx_cnt = SLLIN_BUFF_SYNC;
856 pr_debug("sllin: Break sent.\n");
857 set_bit(SLF_RXEVENT, &sl->flags);
858 wake_up(&sl->kwt_wq);
862 #endif /* BREAK_BY_BAUD */
865 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
867 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
869 sllin_report_error(sl, LIN_ERR_RX_TIMEOUT);
870 set_bit(SLF_TMOUTEVENT, &sl->flags);
871 wake_up(&sl->kwt_wq);
873 return HRTIMER_NORESTART;
877 * sllin_rx_validate() -- Validate received frame, i,e. check checksum
881 static int sllin_rx_validate(struct sllin *sl)
887 unsigned char rec_chcksm = sl->rx_buff[sl->rx_cnt - 1];
888 struct sllin_conf_entry *sce;
890 actual_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
891 sce = &sl->linfr_cache[actual_id];
893 spin_lock_irqsave(&sl->linfr_lock, flags);
895 ext_chcks_fl = sce->frame_fl & LIN_CHECKSUM_EXTENDED;
896 spin_unlock_irqrestore(&sl->linfr_lock, flags);
898 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) !=
901 /* Type of checksum is configured for particular frame */
905 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1,
906 !ext_chcks_fl) != rec_chcksm) {
915 /*****************************************
916 * sllin_kwthread - kernel worker thread
917 *****************************************/
919 int sllin_kwthread(void *ptr)
921 struct sllin *sl = (struct sllin *)ptr;
922 struct tty_struct *tty = sl->tty;
923 struct sched_param schparam = { .sched_priority = 40 };
924 int tx_bytes = 0; /* Used for Network statistics */
927 pr_debug("sllin: sllin_kwthread started.\n");
928 sched_setscheduler(current, SCHED_FIFO, &schparam);
930 clear_bit(SLF_ERROR, &sl->flags);
931 sltty_change_speed(tty, sl->lin_baud);
933 while (!kthread_should_stop()) {
934 struct can_frame *cf;
937 u8 lin_data_buff[SLLIN_DATA_MAX];
940 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
942 if (sllin_send_break(sl) < 0) {
943 /* error processing */
947 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
948 test_bit(SLF_RXEVENT, &sl->flags) ||
949 test_bit(SLF_TXEVENT, &sl->flags) ||
950 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
951 test_bit(SLF_ERROR, &sl->flags) ||
952 (((sl->lin_state == SLSTATE_IDLE) ||
953 (sl->lin_state == SLSTATE_RESPONSE_WAIT))
954 && test_bit(SLF_MSGEVENT, &sl->flags)));
956 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
957 pr_debug("sllin: sllin_kthread RXEVENT\n");
960 if (test_and_clear_bit(SLF_ERROR, &sl->flags)) {
961 unsigned long usleep_range_min;
962 unsigned long usleep_range_max;
963 hrtimer_cancel(&sl->rx_timer);
964 pr_debug("sllin: sllin_kthread ERROR\n");
966 if (sl->lin_state != SLSTATE_IDLE)
967 sllin_report_error(sl, LIN_ERR_FRAMING);
969 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR * 10) /
971 usleep_range_max = usleep_range_min + 50;
972 usleep_range(usleep_range_min, usleep_range_max);
973 sllin_reset_buffs(sl);
974 sl->lin_state = SLSTATE_IDLE;
977 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
978 pr_debug("sllin: sllin_kthread TXEVENT\n");
981 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
982 pr_debug("sllin: sllin_kthread TMOUTEVENT\n");
983 sllin_reset_buffs(sl);
985 sl->lin_state = SLSTATE_IDLE;
988 switch (sl->lin_state) {
990 if (!test_bit(SLF_MSGEVENT, &sl->flags))
993 cf = (struct can_frame *)sl->tx_req_skb->data;
995 /* SFF RTR CAN frame -> LIN header */
996 if (cf->can_id & CAN_RTR_FLAG) {
998 struct sllin_conf_entry *sce;
1000 pr_debug("sllin: %s: RTR SFF CAN frame, ID = %x\n",
1001 __func__, cf->can_id & LIN_ID_MASK);
1003 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
1004 spin_lock_irqsave(&sl->linfr_lock, flags);
1006 /* Is there Slave response in linfr_cache to be sent? */
1007 if ((sce->frame_fl & LIN_CACHE_RESPONSE)
1008 && (sce->dlc > 0)) {
1010 pr_debug("sllin: Sending LIN response from linfr_cache\n");
1012 lin_data = sce->data;
1014 if (lin_dlc > SLLIN_DATA_MAX)
1015 lin_dlc = SLLIN_DATA_MAX;
1016 memcpy(lin_data_buff, lin_data, lin_dlc);
1017 lin_data = lin_data_buff;
1022 spin_unlock_irqrestore(&sl->linfr_lock, flags);
1024 } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
1025 pr_debug("sllin: %s: NON-RTR SFF CAN frame, ID = %x\n",
1026 __func__, (int)cf->can_id & LIN_ID_MASK);
1028 lin_data = cf->data;
1029 lin_dlc = cf->can_dlc;
1030 if (lin_dlc > SLLIN_DATA_MAX)
1031 lin_dlc = SLLIN_DATA_MAX;
1035 if (sllin_setup_msg(sl, 0, cf->can_id & LIN_ID_MASK,
1036 lin_data, lin_dlc) != -1) {
1038 sl->id_to_send = true;
1039 sl->data_to_send = (lin_data != NULL) ? true : false;
1040 sl->resp_len_known = (lin_dlc > 0) ? true : false;
1041 sl->dev->stats.tx_packets++;
1042 sl->dev->stats.tx_bytes += tx_bytes;
1045 clear_bit(SLF_MSGEVENT, &sl->flags);
1046 kfree_skb(sl->tx_req_skb);
1047 netif_wake_queue(sl->dev);
1048 hrtimer_start(&sl->rx_timer,
1049 ktime_add(ktime_get(), sl->rx_timer_timeout),
1053 case SLSTATE_BREAK_SENT:
1054 #ifdef BREAK_BY_BAUD
1055 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
1058 res = sltty_change_speed(tty, sl->lin_baud);
1061 sl->lin_state = SLSTATE_ID_SENT;
1062 sllin_send_tx_buff(sl);
1065 case SLSTATE_ID_SENT:
1066 hrtimer_cancel(&sl->rx_timer);
1067 sl->id_to_send = false;
1068 if (sl->data_to_send) {
1069 sllin_send_tx_buff(sl);
1070 sl->lin_state = SLSTATE_RESPONSE_SENT;
1071 sl->rx_expect = sl->tx_lim;
1072 goto slstate_response_sent;
1074 if (sl->resp_len_known) {
1075 sl->rx_expect = sl->rx_lim;
1077 sl->rx_expect = SLLIN_BUFF_DATA + 2;
1079 sl->lin_state = SLSTATE_RESPONSE_WAIT;
1080 /* If we don't receive anything, timer will "unblock" us */
1081 hrtimer_start(&sl->rx_timer,
1082 ktime_add(ktime_get(), sl->rx_timer_timeout),
1084 goto slstate_response_wait;
1088 case SLSTATE_RESPONSE_WAIT:
1089 slstate_response_wait:
1090 if (test_bit(SLF_MSGEVENT, &sl->flags)) {
1091 unsigned char *lin_buff;
1092 cf = (struct can_frame *)sl->tx_req_skb->data;
1094 lin_buff = (sl->lin_master) ? sl->tx_buff : sl->rx_buff;
1095 if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & LIN_ID_MASK)) {
1096 hrtimer_cancel(&sl->rx_timer);
1097 pr_debug("sllin: received LIN response in a CAN frame.\n");
1098 if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY,
1099 cf->can_id & LIN_ID_MASK,
1100 cf->data, cf->can_dlc) != -1) {
1102 sl->rx_expect = sl->tx_lim;
1103 sl->data_to_send = true;
1104 sl->dev->stats.tx_packets++;
1105 sl->dev->stats.tx_bytes += tx_bytes;
1107 if (!sl->lin_master) {
1108 sl->tx_cnt = SLLIN_BUFF_DATA;
1111 sllin_send_tx_buff(sl);
1112 clear_bit(SLF_MSGEVENT, &sl->flags);
1113 kfree_skb(sl->tx_req_skb);
1114 netif_wake_queue(sl->dev);
1116 sl->lin_state = SLSTATE_RESPONSE_SENT;
1117 goto slstate_response_sent;
1120 sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
1124 /* Be aware, no BREAK here */
1125 case SLSTATE_RESPONSE_WAIT_BUS:
1126 if (sl->rx_cnt < sl->rx_expect)
1129 hrtimer_cancel(&sl->rx_timer);
1130 pr_debug("sllin: response received ID %d len %d\n",
1131 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1133 if (sllin_rx_validate(sl) == -1) {
1134 pr_debug("sllin: RX validation failed.\n");
1135 sllin_report_error(sl, LIN_ERR_CHECKSUM);
1137 /* Send CAN non-RTR frame with data */
1138 pr_debug("sllin: sending NON-RTR CAN"
1139 "frame with LIN payload.");
1140 sll_bump(sl); /* send packet to the network layer */
1143 sl->id_to_send = false;
1144 sl->lin_state = SLSTATE_IDLE;
1147 case SLSTATE_RESPONSE_SENT:
1148 slstate_response_sent:
1149 if (sl->rx_cnt < sl->tx_lim)
1152 hrtimer_cancel(&sl->rx_timer);
1153 sll_bump(sl); /* send packet to the network layer */
1154 pr_debug("sllin: response sent ID %d len %d\n",
1155 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1157 sl->id_to_send = false;
1158 sl->lin_state = SLSTATE_IDLE;
1163 hrtimer_cancel(&sl->rx_timer);
1164 pr_debug("sllin: sllin_kwthread stopped.\n");
1170 /************************************
1171 * sllin_open helper routines.
1172 ************************************/
1174 /* Collect hanged up channels */
1175 static void sll_sync(void)
1178 struct net_device *dev;
1181 for (i = 0; i < maxdev; i++) {
1182 dev = sllin_devs[i];
1186 sl = netdev_priv(dev);
1189 if (dev->flags & IFF_UP)
1194 /* Find a free SLLIN channel, and link in this `tty' line. */
1195 static struct sllin *sll_alloc(dev_t line)
1198 struct net_device *dev = NULL;
1201 if (sllin_devs == NULL)
1202 return NULL; /* Master array missing ! */
1204 for (i = 0; i < maxdev; i++) {
1205 dev = sllin_devs[i];
1211 /* Sorry, too many, all slots in use */
1216 sl = netdev_priv(dev);
1217 if (test_bit(SLF_INUSE, &sl->flags)) {
1218 unregister_netdevice(dev);
1220 sllin_devs[i] = NULL;
1225 char name[IFNAMSIZ];
1226 sprintf(name, "sllin%d", i);
1228 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
1234 sl = netdev_priv(dev);
1235 /* Initialize channel control data */
1236 sl->magic = SLLIN_MAGIC;
1238 spin_lock_init(&sl->lock);
1239 spin_lock_init(&sl->linfr_lock);
1240 sllin_devs[i] = dev;
1246 * Open the high-level part of the SLLIN channel.
1247 * This function is called by the TTY module when the
1248 * SLLIN line discipline is called for. Because we are
1249 * sure the tty line exists, we only have to link it to
1250 * a free SLLIN channel...
1252 * Called in process context serialized from other ldisc calls.
1255 static int sllin_open(struct tty_struct *tty)
1259 pr_debug("sllin: %s() invoked\n", __func__);
1261 if (!capable(CAP_NET_ADMIN))
1264 if (tty->ops->write == NULL)
1267 /* RTnetlink lock is misused here to serialize concurrent
1268 opens of sllin channels. There are better ways, but it is
1273 /* Collect hanged up channels. */
1276 sl = tty->disc_data;
1279 /* First make sure we're not already connected. */
1280 if (sl && sl->magic == SLLIN_MAGIC)
1283 /* OK. Find a free SLLIN channel to use. */
1285 sl = sll_alloc(tty_devnum(tty));
1290 tty->disc_data = sl;
1291 sl->line = tty_devnum(tty);
1293 if (!test_bit(SLF_INUSE, &sl->flags)) {
1294 /* Perform the low-level SLLIN initialization. */
1295 sl->lin_master = master;
1298 pr_debug("sllin: Configured as MASTER\n");
1300 pr_debug("sllin: Configured as SLAVE\n");
1303 sllin_reset_buffs(sl);
1305 sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
1306 pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
1308 sl->lin_state = SLSTATE_IDLE;
1310 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1311 sl->rx_timer.function = sllin_rx_timeout_handler;
1312 /* timeval_to_ktime(msg_head->ival1); */
1313 sl->rx_timer_timeout = ns_to_ktime(
1314 (1000000000l / sl->lin_baud) *
1315 SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT);
1317 set_bit(SLF_INUSE, &sl->flags);
1319 init_waitqueue_head(&sl->kwt_wq);
1320 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
1321 if (sl->kwthread == NULL)
1324 err = register_netdevice(sl->dev);
1326 goto err_free_chan_and_thread;
1329 /* Done. We have linked the TTY line to a channel. */
1331 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
1333 /* TTY layer expects 0 on success */
1336 err_free_chan_and_thread:
1337 kthread_stop(sl->kwthread);
1338 sl->kwthread = NULL;
1342 tty->disc_data = NULL;
1343 clear_bit(SLF_INUSE, &sl->flags);
1348 /* Count references from TTY module */
1353 * Close down a SLLIN channel.
1354 * This means flushing out any pending queues, and then returning. This
1355 * call is serialized against other ldisc functions.
1357 * We also use this method for a hangup event.
1360 static void sllin_close(struct tty_struct *tty)
1362 struct sllin *sl = (struct sllin *) tty->disc_data;
1364 /* First make sure we're connected. */
1365 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
1368 kthread_stop(sl->kwthread);
1369 sl->kwthread = NULL;
1371 tty->disc_data = NULL;
1374 /* Flush network side */
1375 unregister_netdev(sl->dev);
1376 /* This will complete via sl_free_netdev */
1379 static int sllin_hangup(struct tty_struct *tty)
1385 /* Perform I/O control on an active SLLIN channel. */
1386 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
1387 unsigned int cmd, unsigned long arg)
1389 struct sllin *sl = (struct sllin *) tty->disc_data;
1392 /* First make sure we're connected. */
1393 if (!sl || sl->magic != SLLIN_MAGIC)
1398 tmp = strlen(sl->dev->name) + 1;
1399 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1407 return tty_mode_ioctl(tty, file, cmd, arg);
1411 static struct tty_ldisc_ops sll_ldisc = {
1412 .owner = THIS_MODULE,
1413 .magic = TTY_LDISC_MAGIC,
1416 .close = sllin_close,
1417 .hangup = sllin_hangup,
1418 .ioctl = sllin_ioctl,
1419 .receive_buf = sllin_receive_buf,
1420 .write_wakeup = sllin_write_wakeup,
1423 static int __init sllin_init(void)
1428 maxdev = 4; /* Sanity */
1431 pr_debug("sllin: %d dynamic interface channels.\n", maxdev);
1433 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1435 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1439 /* Fill in our line protocol discipline, and register it */
1440 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1442 printk(KERN_ERR "sllin: can't register line discipline\n");
1446 #ifdef BREAK_BY_BAUD
1447 pr_debug("sllin: Break is generated by baud-rate change.");
1449 pr_debug("sllin: Break is generated manually with tiny sleep.");
1455 static void __exit sllin_exit(void)
1458 struct net_device *dev;
1460 unsigned long timeout = jiffies + HZ;
1463 if (sllin_devs == NULL)
1466 /* First of all: check for active disciplines and hangup them.
1470 msleep_interruptible(100);
1473 for (i = 0; i < maxdev; i++) {
1474 dev = sllin_devs[i];
1477 sl = netdev_priv(dev);
1478 spin_lock_bh(&sl->lock);
1481 tty_hangup(sl->tty);
1483 spin_unlock_bh(&sl->lock);
1485 } while (busy && time_before(jiffies, timeout));
1487 /* FIXME: hangup is async so we should wait when doing this second
1490 for (i = 0; i < maxdev; i++) {
1491 dev = sllin_devs[i];
1494 sllin_devs[i] = NULL;
1496 sl = netdev_priv(dev);
1498 printk(KERN_ERR "%s: tty discipline still running\n",
1500 /* Intentionally leak the control block. */
1501 dev->destructor = NULL;
1504 unregister_netdev(dev);
1510 i = tty_unregister_ldisc(N_SLLIN);
1512 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1515 module_init(sllin_init);
1516 module_exit(sllin_exit);