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_LOC_SLAVE_CACHE) {
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_ID_CONF))
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);
722 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
727 static void sllin_reset_buffs(struct sllin *sl)
731 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
734 sl->id_to_send = false;
735 sl->data_to_send = false;
738 int sllin_send_tx_buff(struct sllin *sl)
740 struct tty_struct *tty = sl->tty;
744 set_bit(SLF_TXBUFF_RQ, &sl->flags);
746 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
747 return 0; /* ongoing concurrent processing */
749 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
750 smp_mb__after_clear_bit();
753 if (sl->lin_state != SLSTATE_BREAK_SENT)
754 remains = sl->tx_lim - sl->tx_cnt;
758 remains = sl->tx_lim - sl->tx_cnt;
761 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
769 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
770 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
772 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
780 pr_debug("sllin: sllin_send_tx_buff sent %d, remains %d\n",
781 sl->tx_cnt, remains);
783 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
784 smp_mb__after_clear_bit();
786 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
791 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
797 int sllin_send_break(struct sllin *sl)
799 struct tty_struct *tty = sl->tty;
800 unsigned long break_baud;
803 break_baud = ((sl->lin_baud * 2) / 3);
804 sltty_change_speed(tty, break_baud);
806 tty->ops->flush_buffer(tty);
807 sl->rx_cnt = SLLIN_BUFF_BREAK;
809 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
810 sl->lin_state = SLSTATE_BREAK_SENT;
812 res = sllin_send_tx_buff(sl);
814 sl->lin_state = SLSTATE_IDLE;
820 #else /* BREAK_BY_BAUD */
822 int sllin_send_break(struct sllin *sl)
824 struct tty_struct *tty = sl->tty;
826 unsigned long break_baud;
827 unsigned long usleep_range_min;
828 unsigned long usleep_range_max;
830 break_baud = ((sl->lin_baud * 2) / 3);
831 sl->rx_cnt = SLLIN_BUFF_BREAK;
832 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
833 sl->lin_state = SLSTATE_BREAK_SENT;
835 /* Do the break ourselves; Inspired by
836 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
837 retval = tty->ops->break_ctl(tty, -1);
842 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR) / break_baud;
843 usleep_range_max = usleep_range_min + 50;
844 usleep_range(usleep_range_min, usleep_range_max);
846 retval = tty->ops->break_ctl(tty, 0);
847 usleep_range_min = (1000000l * 1 /* 1 bit */) / break_baud;
848 usleep_range_max = usleep_range_min + 30;
849 usleep_range(usleep_range_min, usleep_range_max);
851 tty->ops->flush_buffer(tty);
853 sl->tx_cnt = SLLIN_BUFF_SYNC;
855 pr_debug("sllin: Break sent.\n");
856 set_bit(SLF_RXEVENT, &sl->flags);
857 wake_up(&sl->kwt_wq);
861 #endif /* BREAK_BY_BAUD */
864 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
866 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
868 sllin_report_error(sl, LIN_ERR_RX_TIMEOUT);
869 set_bit(SLF_TMOUTEVENT, &sl->flags);
870 wake_up(&sl->kwt_wq);
872 return HRTIMER_NORESTART;
876 * sllin_rx_validate() -- Validate received frame, i,e. check checksum
880 static int sllin_rx_validate(struct sllin *sl)
886 unsigned char rec_chcksm = sl->rx_buff[sl->rx_cnt - 1];
887 struct sllin_conf_entry *sce;
889 actual_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
890 sce = &sl->linfr_cache[actual_id];
892 spin_lock_irqsave(&sl->linfr_lock, flags);
894 ext_chcks_fl = sce->frame_fl & LIN_CHECKSUM_EXTENDED;
895 spin_unlock_irqrestore(&sl->linfr_lock, flags);
897 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) !=
900 /* Type of checksum is configured for particular frame */
904 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1,
905 !ext_chcks_fl) != rec_chcksm) {
914 /*****************************************
915 * sllin_kwthread - kernel worker thread
916 *****************************************/
918 int sllin_kwthread(void *ptr)
920 struct sllin *sl = (struct sllin *)ptr;
921 struct tty_struct *tty = sl->tty;
922 struct sched_param schparam = { .sched_priority = 40 };
923 int tx_bytes = 0; /* Used for Network statistics */
926 pr_debug("sllin: sllin_kwthread started.\n");
927 sched_setscheduler(current, SCHED_FIFO, &schparam);
929 clear_bit(SLF_ERROR, &sl->flags);
930 sltty_change_speed(tty, sl->lin_baud);
932 while (!kthread_should_stop()) {
933 struct can_frame *cf;
936 u8 lin_data_buff[SLLIN_DATA_MAX];
939 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
941 if (sllin_send_break(sl) < 0) {
942 /* error processing */
946 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
947 test_bit(SLF_RXEVENT, &sl->flags) ||
948 test_bit(SLF_TXEVENT, &sl->flags) ||
949 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
950 test_bit(SLF_ERROR, &sl->flags) ||
951 (((sl->lin_state == SLSTATE_IDLE) ||
952 (sl->lin_state == SLSTATE_RESPONSE_WAIT))
953 && test_bit(SLF_MSGEVENT, &sl->flags)));
955 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
956 pr_debug("sllin: sllin_kthread RXEVENT\n");
959 if (test_and_clear_bit(SLF_ERROR, &sl->flags)) {
960 unsigned long usleep_range_min;
961 unsigned long usleep_range_max;
962 hrtimer_cancel(&sl->rx_timer);
963 pr_debug("sllin: sllin_kthread ERROR\n");
965 if (sl->lin_state != SLSTATE_IDLE)
966 sllin_report_error(sl, LIN_ERR_FRAMING);
968 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR * 10) /
970 usleep_range_max = usleep_range_min + 50;
971 usleep_range(usleep_range_min, usleep_range_max);
972 sllin_reset_buffs(sl);
973 sl->lin_state = SLSTATE_IDLE;
976 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
977 pr_debug("sllin: sllin_kthread TXEVENT\n");
980 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
981 pr_debug("sllin: sllin_kthread TMOUTEVENT\n");
982 sllin_reset_buffs(sl);
984 sl->lin_state = SLSTATE_IDLE;
987 switch (sl->lin_state) {
989 if (!test_bit(SLF_MSGEVENT, &sl->flags))
992 cf = (struct can_frame *)sl->tx_req_skb->data;
994 /* SFF RTR CAN frame -> LIN header */
995 if (cf->can_id & CAN_RTR_FLAG) {
997 struct sllin_conf_entry *sce;
999 pr_debug("sllin: %s: RTR SFF CAN frame, ID = %x\n",
1000 __func__, cf->can_id & LIN_ID_MASK);
1002 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
1003 spin_lock_irqsave(&sl->linfr_lock, flags);
1005 /* Is there Slave response in linfr_cache to be sent? */
1006 if ((sce->frame_fl & LIN_LOC_SLAVE_CACHE)
1007 && (sce->dlc > 0)) {
1009 pr_debug("sllin: Sending LIN response from linfr_cache\n");
1011 lin_data = sce->data;
1013 if (lin_dlc > SLLIN_DATA_MAX)
1014 lin_dlc = SLLIN_DATA_MAX;
1015 memcpy(lin_data_buff, lin_data, lin_dlc);
1016 lin_data = lin_data_buff;
1021 spin_unlock_irqrestore(&sl->linfr_lock, flags);
1023 } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
1024 pr_debug("sllin: %s: NON-RTR SFF CAN frame, ID = %x\n",
1025 __func__, (int)cf->can_id & LIN_ID_MASK);
1027 lin_data = cf->data;
1028 lin_dlc = cf->can_dlc;
1029 if (lin_dlc > SLLIN_DATA_MAX)
1030 lin_dlc = SLLIN_DATA_MAX;
1034 if (sllin_setup_msg(sl, 0, cf->can_id & LIN_ID_MASK,
1035 lin_data, lin_dlc) != -1) {
1037 sl->id_to_send = true;
1038 sl->data_to_send = (lin_data != NULL) ? true : false;
1039 sl->resp_len_known = (lin_dlc > 0) ? true : false;
1040 sl->dev->stats.tx_packets++;
1041 sl->dev->stats.tx_bytes += tx_bytes;
1044 clear_bit(SLF_MSGEVENT, &sl->flags);
1045 kfree_skb(sl->tx_req_skb);
1046 netif_wake_queue(sl->dev);
1047 hrtimer_start(&sl->rx_timer,
1048 ktime_add(ktime_get(), sl->rx_timer_timeout),
1052 case SLSTATE_BREAK_SENT:
1053 #ifdef BREAK_BY_BAUD
1054 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
1057 res = sltty_change_speed(tty, sl->lin_baud);
1060 sl->lin_state = SLSTATE_ID_SENT;
1061 sllin_send_tx_buff(sl);
1064 case SLSTATE_ID_SENT:
1065 hrtimer_cancel(&sl->rx_timer);
1066 sl->id_to_send = false;
1067 if (sl->data_to_send) {
1068 sllin_send_tx_buff(sl);
1069 sl->lin_state = SLSTATE_RESPONSE_SENT;
1070 sl->rx_expect = sl->tx_lim;
1071 goto slstate_response_sent;
1073 if (sl->resp_len_known) {
1074 sl->rx_expect = sl->rx_lim;
1076 sl->rx_expect = SLLIN_BUFF_DATA + 2;
1078 sl->lin_state = SLSTATE_RESPONSE_WAIT;
1079 /* If we don't receive anything, timer will "unblock" us */
1080 hrtimer_start(&sl->rx_timer,
1081 ktime_add(ktime_get(), sl->rx_timer_timeout),
1083 goto slstate_response_wait;
1087 case SLSTATE_RESPONSE_WAIT:
1088 slstate_response_wait:
1089 if (test_bit(SLF_MSGEVENT, &sl->flags)) {
1090 unsigned char *lin_buff;
1091 cf = (struct can_frame *)sl->tx_req_skb->data;
1093 lin_buff = (sl->lin_master) ? sl->tx_buff : sl->rx_buff;
1094 if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & LIN_ID_MASK)) {
1095 hrtimer_cancel(&sl->rx_timer);
1096 pr_debug("sllin: received LIN response in a CAN frame.\n");
1097 if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY,
1098 cf->can_id & LIN_ID_MASK,
1099 cf->data, cf->can_dlc) != -1) {
1101 sl->rx_expect = sl->tx_lim;
1102 sl->data_to_send = true;
1103 sl->dev->stats.tx_packets++;
1104 sl->dev->stats.tx_bytes += tx_bytes;
1106 if (!sl->lin_master) {
1107 sl->tx_cnt = SLLIN_BUFF_DATA;
1110 sllin_send_tx_buff(sl);
1111 clear_bit(SLF_MSGEVENT, &sl->flags);
1112 kfree_skb(sl->tx_req_skb);
1113 netif_wake_queue(sl->dev);
1115 sl->lin_state = SLSTATE_RESPONSE_SENT;
1116 goto slstate_response_sent;
1119 sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
1123 /* Be aware, no BREAK here */
1124 case SLSTATE_RESPONSE_WAIT_BUS:
1125 if (sl->rx_cnt < sl->rx_expect)
1128 hrtimer_cancel(&sl->rx_timer);
1129 pr_debug("sllin: response received ID %d len %d\n",
1130 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1132 if (sllin_rx_validate(sl) == -1) {
1133 pr_debug("sllin: RX validation failed.\n");
1134 sllin_report_error(sl, LIN_ERR_CHECKSUM);
1136 /* Send CAN non-RTR frame with data */
1137 pr_debug("sllin: sending NON-RTR CAN"
1138 "frame with LIN payload.");
1139 sll_bump(sl); /* send packet to the network layer */
1142 sl->id_to_send = false;
1143 sl->lin_state = SLSTATE_IDLE;
1146 case SLSTATE_RESPONSE_SENT:
1147 slstate_response_sent:
1148 if (sl->rx_cnt < sl->tx_lim)
1151 hrtimer_cancel(&sl->rx_timer);
1152 sll_bump(sl); /* send packet to the network layer */
1153 pr_debug("sllin: response sent ID %d len %d\n",
1154 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1156 sl->id_to_send = false;
1157 sl->lin_state = SLSTATE_IDLE;
1162 hrtimer_cancel(&sl->rx_timer);
1163 pr_debug("sllin: sllin_kwthread stopped.\n");
1169 /************************************
1170 * sllin_open helper routines.
1171 ************************************/
1173 /* Collect hanged up channels */
1174 static void sll_sync(void)
1177 struct net_device *dev;
1180 for (i = 0; i < maxdev; i++) {
1181 dev = sllin_devs[i];
1185 sl = netdev_priv(dev);
1188 if (dev->flags & IFF_UP)
1193 /* Find a free SLLIN channel, and link in this `tty' line. */
1194 static struct sllin *sll_alloc(dev_t line)
1197 struct net_device *dev = NULL;
1200 if (sllin_devs == NULL)
1201 return NULL; /* Master array missing ! */
1203 for (i = 0; i < maxdev; i++) {
1204 dev = sllin_devs[i];
1210 /* Sorry, too many, all slots in use */
1215 sl = netdev_priv(dev);
1216 if (test_bit(SLF_INUSE, &sl->flags)) {
1217 unregister_netdevice(dev);
1219 sllin_devs[i] = NULL;
1224 char name[IFNAMSIZ];
1225 sprintf(name, "sllin%d", i);
1227 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
1233 sl = netdev_priv(dev);
1234 /* Initialize channel control data */
1235 sl->magic = SLLIN_MAGIC;
1237 spin_lock_init(&sl->lock);
1238 spin_lock_init(&sl->linfr_lock);
1239 sllin_devs[i] = dev;
1245 * Open the high-level part of the SLLIN channel.
1246 * This function is called by the TTY module when the
1247 * SLLIN line discipline is called for. Because we are
1248 * sure the tty line exists, we only have to link it to
1249 * a free SLLIN channel...
1251 * Called in process context serialized from other ldisc calls.
1254 static int sllin_open(struct tty_struct *tty)
1258 pr_debug("sllin: %s() invoked\n", __func__);
1260 if (!capable(CAP_NET_ADMIN))
1263 if (tty->ops->write == NULL)
1266 /* RTnetlink lock is misused here to serialize concurrent
1267 opens of sllin channels. There are better ways, but it is
1272 /* Collect hanged up channels. */
1275 sl = tty->disc_data;
1278 /* First make sure we're not already connected. */
1279 if (sl && sl->magic == SLLIN_MAGIC)
1282 /* OK. Find a free SLLIN channel to use. */
1284 sl = sll_alloc(tty_devnum(tty));
1289 tty->disc_data = sl;
1290 sl->line = tty_devnum(tty);
1292 if (!test_bit(SLF_INUSE, &sl->flags)) {
1293 /* Perform the low-level SLLIN initialization. */
1294 sl->lin_master = master;
1297 pr_debug("sllin: Configured as MASTER\n");
1299 pr_debug("sllin: Configured as SLAVE\n");
1302 sllin_reset_buffs(sl);
1304 sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
1305 pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
1307 sl->lin_state = SLSTATE_IDLE;
1309 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1310 sl->rx_timer.function = sllin_rx_timeout_handler;
1311 /* timeval_to_ktime(msg_head->ival1); */
1312 sl->rx_timer_timeout = ns_to_ktime(
1313 (1000000000l / sl->lin_baud) *
1314 SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT);
1316 set_bit(SLF_INUSE, &sl->flags);
1318 init_waitqueue_head(&sl->kwt_wq);
1319 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
1320 if (sl->kwthread == NULL)
1323 err = register_netdevice(sl->dev);
1325 goto err_free_chan_and_thread;
1328 /* Done. We have linked the TTY line to a channel. */
1330 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
1332 /* TTY layer expects 0 on success */
1335 err_free_chan_and_thread:
1336 kthread_stop(sl->kwthread);
1337 sl->kwthread = NULL;
1341 tty->disc_data = NULL;
1342 clear_bit(SLF_INUSE, &sl->flags);
1347 /* Count references from TTY module */
1352 * Close down a SLLIN channel.
1353 * This means flushing out any pending queues, and then returning. This
1354 * call is serialized against other ldisc functions.
1356 * We also use this method for a hangup event.
1359 static void sllin_close(struct tty_struct *tty)
1361 struct sllin *sl = (struct sllin *) tty->disc_data;
1363 /* First make sure we're connected. */
1364 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
1367 kthread_stop(sl->kwthread);
1368 sl->kwthread = NULL;
1370 tty->disc_data = NULL;
1373 /* Flush network side */
1374 unregister_netdev(sl->dev);
1375 /* This will complete via sl_free_netdev */
1378 static int sllin_hangup(struct tty_struct *tty)
1384 /* Perform I/O control on an active SLLIN channel. */
1385 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
1386 unsigned int cmd, unsigned long arg)
1388 struct sllin *sl = (struct sllin *) tty->disc_data;
1391 /* First make sure we're connected. */
1392 if (!sl || sl->magic != SLLIN_MAGIC)
1397 tmp = strlen(sl->dev->name) + 1;
1398 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1406 return tty_mode_ioctl(tty, file, cmd, arg);
1410 static struct tty_ldisc_ops sll_ldisc = {
1411 .owner = THIS_MODULE,
1412 .magic = TTY_LDISC_MAGIC,
1415 .close = sllin_close,
1416 .hangup = sllin_hangup,
1417 .ioctl = sllin_ioctl,
1418 .receive_buf = sllin_receive_buf,
1419 .write_wakeup = sllin_write_wakeup,
1422 static int __init sllin_init(void)
1427 maxdev = 4; /* Sanity */
1430 pr_debug("sllin: %d dynamic interface channels.\n", maxdev);
1432 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1434 printk(KERN_ERR "sllin: can't allocate sllin device array!\n");
1438 /* Fill in our line protocol discipline, and register it */
1439 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1441 printk(KERN_ERR "sllin: can't register line discipline\n");
1445 #ifdef BREAK_BY_BAUD
1446 pr_debug("sllin: Break is generated by baud-rate change.");
1448 pr_debug("sllin: Break is generated manually with tiny sleep.");
1454 static void __exit sllin_exit(void)
1457 struct net_device *dev;
1459 unsigned long timeout = jiffies + HZ;
1462 if (sllin_devs == NULL)
1465 /* First of all: check for active disciplines and hangup them.
1469 msleep_interruptible(100);
1472 for (i = 0; i < maxdev; i++) {
1473 dev = sllin_devs[i];
1476 sl = netdev_priv(dev);
1477 spin_lock_bh(&sl->lock);
1480 tty_hangup(sl->tty);
1482 spin_unlock_bh(&sl->lock);
1484 } while (busy && time_before(jiffies, timeout));
1486 /* FIXME: hangup is async so we should wait when doing this second
1489 for (i = 0; i < maxdev; i++) {
1490 dev = sllin_devs[i];
1493 sllin_devs[i] = NULL;
1495 sl = netdev_priv(dev);
1497 printk(KERN_ERR "%s: tty discipline still running\n",
1499 /* Intentionally leak the control block. */
1500 dev->destructor = NULL;
1503 unregister_netdev(dev);
1509 i = tty_unregister_ldisc(N_SLLIN);
1511 printk(KERN_ERR "sllin: can't unregister ldisc (err %d)\n", i);
1514 module_init(sllin_init);
1515 module_exit(sllin_exit);