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 <linux/uaccess.h>
50 #include <linux/bitops.h>
51 #include <linux/string.h>
52 #include <linux/tty.h>
53 #include <linux/errno.h>
54 #include <linux/netdevice.h>
55 #include <linux/skbuff.h>
56 #include <linux/rtnetlink.h>
57 #include <linux/if_arp.h>
58 #include <linux/if_ether.h>
59 #include <linux/sched.h>
60 #include <linux/delay.h>
61 #include <linux/init.h>
62 #include <linux/can.h>
63 #include <linux/kthread.h>
64 #include <linux/hrtimer.h>
65 #include <linux/version.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 bool 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) */
118 SLSTATE_RESPONSE_SENT,
121 struct sllin_conf_entry {
122 int dlc; /* Length of data in LIN frame */
123 canid_t frame_fl; /* LIN frame flags. Passed from userspace as
125 u8 data[8]; /* LIN frame data payload */
131 /* Various fields. */
132 struct tty_struct *tty; /* ptr to TTY structure */
133 struct net_device *dev; /* easy for intr handling */
136 /* LIN message buffer and actual processed data counts */
137 unsigned char rx_buff[SLLIN_BUFF_LEN]; /* LIN Rx buffer */
138 unsigned char tx_buff[SLLIN_BUFF_LEN]; /* LIN Tx buffer */
139 int rx_expect; /* expected number of Rx chars */
140 int rx_lim; /* maximum Rx chars for current frame */
141 int rx_cnt; /* message buffer Rx fill level */
142 int tx_lim; /* actual limit of bytes to Tx */
143 int tx_cnt; /* number of already Tx bytes */
144 char lin_master; /* node is a master node */
145 int lin_baud; /* LIN baudrate */
146 int lin_state; /* state */
147 char id_to_send; /* there is ID to be sent */
148 char data_to_send; /* there are data to be sent */
149 char resp_len_known; /* Length of the response is known */
150 char header_received;/* In Slave mode, set when header was already
152 char rx_len_unknown; /* We are not sure how much data will be sent to us --
153 we just guess the length */
155 unsigned long flags; /* Flag values/ mode etc */
156 #define SLF_INUSE 0 /* Channel in use */
157 #define SLF_ERROR 1 /* Parity, etc. error */
158 #define SLF_RXEVENT 2 /* Rx wake event */
159 #define SLF_TXEVENT 3 /* Tx wake event */
160 #define SLF_MSGEVENT 4 /* CAN message to sent */
161 #define SLF_TMOUTEVENT 5 /* Timeout on received data */
162 #define SLF_TXBUFF_RQ 6 /* Req. to send buffer to UART*/
163 #define SLF_TXBUFF_INPR 7 /* Above request in progress */
166 struct task_struct *kwthread;
167 wait_queue_head_t kwt_wq; /* Wait queue used by kwthread */
168 struct hrtimer rx_timer; /* RX timeout timer */
169 ktime_t rx_timer_timeout; /* RX timeout timer value */
170 struct sk_buff *tx_req_skb; /* Socket buffer with CAN frame
171 received from network stack*/
173 /* List with configurations for each of 0 to LIN_ID_MAX LIN IDs */
174 struct sllin_conf_entry linfr_cache[LIN_ID_MAX + 1];
175 spinlock_t linfr_lock; /* frame cache and buffers lock */
178 static struct net_device **sllin_devs;
179 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf);
180 static void sllin_slave_receive_buf(struct tty_struct *tty,
181 const unsigned char *cp, char *fp, int count);
182 static void sllin_master_receive_buf(struct tty_struct *tty,
183 const unsigned char *cp, char *fp, int count);
186 /* Values of two parity bits in LIN Protected
187 Identifier for each particular LIN ID */
188 const unsigned char sllin_id_parity_table[] = {
189 0x80, 0xc0, 0x40, 0x00, 0xc0, 0x80, 0x00, 0x40,
190 0x00, 0x40, 0xc0, 0x80, 0x40, 0x00, 0x80, 0xc0,
191 0x40, 0x00, 0x80, 0xc0, 0x00, 0x40, 0xc0, 0x80,
192 0xc0, 0x80, 0x00, 0x40, 0x80, 0xc0, 0x40, 0x00,
193 0x00, 0x40, 0xc0, 0x80, 0x40, 0x00, 0x80, 0xc0,
194 0x80, 0xc0, 0x40, 0x00, 0xc0, 0x80, 0x00, 0x40,
195 0xc0, 0x80, 0x00, 0x40, 0x80, 0xc0, 0x40, 0x00,
196 0x40, 0x00, 0x80, 0xc0, 0x00, 0x40, 0xc0, 0x80
200 * sltty_change_speed() -- Change baudrate of Serial device belonging
203 * @tty: Pointer to TTY to change speed for.
204 * @speed: Integer value of new speed. It is possible to
205 * assign non-standard values, i.e. those which
206 * are not defined in termbits.h.
208 static int sltty_change_speed(struct tty_struct *tty, unsigned speed)
210 struct ktermios old_termios, termios;
213 mutex_lock(&tty->termios_mutex);
215 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 7, 0)
216 old_termios = termios = *(tty->termios);
218 old_termios = termios = tty->termios;
221 cflag = CS8 | CREAD | CLOCAL | HUPCL;
222 cflag &= ~(CBAUD | CIBAUD);
224 termios.c_cflag = cflag;
228 /* Enable interrupt when UART-Break or Framing error received */
229 termios.c_iflag = BRKINT | INPCK;
230 #if LINUX_VERSION_CODE < KERNEL_VERSION(3, 7, 0)
231 *(tty->termios) = termios;
233 tty->termios = termios;
236 tty_encode_baud_rate(tty, speed, speed);
238 if (tty->ops->set_termios)
239 tty->ops->set_termios(tty, &old_termios);
241 mutex_unlock(&tty->termios_mutex);
246 /* Send one can_frame to the network layer */
247 static void sllin_send_canfr(struct sllin *sl, canid_t id, char *data, int len)
255 memcpy(&cf.data, data, cf.can_dlc);
257 skb = dev_alloc_skb(sizeof(struct can_frame));
262 skb->protocol = htons(ETH_P_CAN);
263 skb->pkt_type = PACKET_BROADCAST;
264 skb->ip_summed = CHECKSUM_UNNECESSARY;
265 memcpy(skb_put(skb, sizeof(struct can_frame)),
266 &cf, sizeof(struct can_frame));
269 sl->dev->stats.rx_packets++;
270 sl->dev->stats.rx_bytes += cf.can_dlc;
274 * sll_bump() -- Send data of received LIN frame (existing in sl->rx_buff)
279 static void sll_bump(struct sllin *sl)
281 int len = sl->rx_cnt - SLLIN_BUFF_DATA - 1; /* without checksum */
282 len = (len < 0) ? 0 : len;
284 sllin_send_canfr(sl, sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK,
285 sl->rx_buff + SLLIN_BUFF_DATA, len);
288 static void sll_send_rtr(struct sllin *sl)
290 sllin_send_canfr(sl, (sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK) |
291 CAN_RTR_FLAG, NULL, 0);
295 * Called by the driver when there's room for more data. If we have
296 * more packets to send, we send them here.
298 static void sllin_write_wakeup(struct tty_struct *tty)
302 struct sllin *sl = (struct sllin *) tty->disc_data;
304 /* First make sure we're connected. */
305 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
308 set_bit(SLF_TXBUFF_RQ, &sl->flags);
310 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
311 return; /* ongoing concurrent processing */
313 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
314 smp_mb__after_clear_bit();
316 if (sl->lin_state != SLSTATE_BREAK_SENT)
317 remains = sl->tx_lim - sl->tx_cnt;
319 remains = SLLIN_BUFF_BREAK + 1 - sl->tx_cnt;
322 actual = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt,
323 sl->tx_cnt - sl->tx_lim);
324 sl->tx_cnt += actual;
327 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
328 smp_mb__after_clear_bit();
330 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
332 if ((remains > 0) && (actual >= 0)) {
333 netdev_dbg(sl->dev, "sllin_write_wakeup sent %d, remains %d, waiting\n",
334 sl->tx_cnt, sl->tx_lim - sl->tx_cnt);
338 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
339 set_bit(SLF_TXEVENT, &sl->flags);
340 wake_up(&sl->kwt_wq);
342 netdev_dbg(sl->dev, "sllin_write_wakeup sent %d, wakeup\n", sl->tx_cnt);
346 * sll_xmit() -- Send a can_frame to a TTY queue.
348 * @skb: Pointer to Socket buffer to be sent.
349 * @dev: Network device where @skb will be sent.
351 static netdev_tx_t sll_xmit(struct sk_buff *skb, struct net_device *dev)
353 struct sllin *sl = netdev_priv(dev);
354 struct can_frame *cf;
356 if (skb->len != sizeof(struct can_frame))
359 spin_lock(&sl->lock);
360 if (!netif_running(dev)) {
361 netdev_warn(sl->dev, "xmit: iface is down\n");
364 if (sl->tty == NULL) {
365 netdev_warn(sl->dev, "xmit: no tty device connected\n");
369 cf = (struct can_frame *) skb->data;
370 if (cf->can_id & LIN_CTRL_FRAME) {
371 sllin_configure_frame_cache(sl, cf);
372 goto free_out_unlock;
375 netif_stop_queue(sl->dev);
377 sl->tx_req_skb = skb;
378 set_bit(SLF_MSGEVENT, &sl->flags);
379 wake_up(&sl->kwt_wq);
380 spin_unlock(&sl->lock);
385 spin_unlock(&sl->lock);
392 /******************************************
393 * Routines looking at netdevice side.
394 ******************************************/
396 /* Netdevice UP -> DOWN routine */
397 static int sll_close(struct net_device *dev)
399 struct sllin *sl = netdev_priv(dev);
401 spin_lock_bh(&sl->lock);
403 /* TTY discipline is running. */
404 clear_bit(TTY_DO_WRITE_WAKEUP, &sl->tty->flags);
406 netif_stop_queue(dev);
409 spin_unlock_bh(&sl->lock);
414 /* Netdevice DOWN -> UP routine */
415 static int sll_open(struct net_device *dev)
417 struct sllin *sl = netdev_priv(dev);
419 netdev_dbg(sl->dev, "%s() invoked\n", __func__);
424 sl->flags &= (1 << SLF_INUSE);
425 netif_start_queue(dev);
429 /* Hook the destructor so we can free sllin devs at the right point in time */
430 static void sll_free_netdev(struct net_device *dev)
432 int i = dev->base_addr;
434 sllin_devs[i] = NULL;
437 static const struct net_device_ops sll_netdev_ops = {
438 .ndo_open = sll_open,
439 .ndo_stop = sll_close,
440 .ndo_start_xmit = sll_xmit,
443 static void sll_setup(struct net_device *dev)
445 dev->netdev_ops = &sll_netdev_ops;
446 dev->destructor = sll_free_netdev;
448 dev->hard_header_len = 0;
450 dev->tx_queue_len = 10;
452 dev->mtu = sizeof(struct can_frame);
453 dev->type = ARPHRD_CAN;
455 /* New-style flags. */
456 dev->flags = IFF_NOARP;
457 dev->features = NETIF_F_HW_CSUM; /* NETIF_F_NO_CSUM;*/
460 /******************************************
461 Routines looking at TTY side.
462 ******************************************/
463 static void sllin_master_receive_buf(struct tty_struct *tty,
464 const unsigned char *cp, char *fp, int count)
466 struct sllin *sl = (struct sllin *) tty->disc_data;
468 /* Read the characters out of the buffer */
471 netdev_dbg(sl->dev, "sllin_master_receive_buf char 0x%02x ignored "
472 "due marker 0x%02x, flags 0x%lx\n",
473 *cp, *(fp-1), sl->flags);
475 /* i.e. Real error -- not Break */
476 if (sl->rx_cnt > SLLIN_BUFF_BREAK) {
477 set_bit(SLF_ERROR, &sl->flags);
478 wake_up(&sl->kwt_wq);
483 #ifndef BREAK_BY_BAUD
484 /* We didn't receive Break character -- fake it! */
485 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
486 netdev_dbg(sl->dev, "LIN_RX[%d]: 0x00\n", sl->rx_cnt);
487 sl->rx_buff[sl->rx_cnt++] = 0x00;
489 #endif /* BREAK_BY_BAUD */
491 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
492 netdev_dbg(sl->dev, "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
493 sl->rx_buff[sl->rx_cnt++] = *cp++;
498 if (sl->rx_cnt >= sl->rx_expect) {
499 set_bit(SLF_RXEVENT, &sl->flags);
500 wake_up(&sl->kwt_wq);
501 netdev_dbg(sl->dev, "sllin_receive_buf count %d, wakeup\n", sl->rx_cnt);
503 netdev_dbg(sl->dev, "sllin_receive_buf count %d, waiting\n", sl->rx_cnt);
508 /*****************************************
509 * sllin message helper routines
510 *****************************************/
512 * sllin_report_error() -- Report an error by sending CAN frame
513 * with particular error flag set in can_id
516 * @err: Error flag to be sent.
518 static void sllin_report_error(struct sllin *sl, int err)
521 case LIN_ERR_CHECKSUM:
522 sl->dev->stats.rx_crc_errors++;
525 case LIN_ERR_RX_TIMEOUT:
526 sl->dev->stats.rx_errors++;
529 case LIN_ERR_FRAMING:
530 sl->dev->stats.rx_frame_errors++;
534 sllin_send_canfr(sl, 0 | CAN_EFF_FLAG |
535 (err & ~LIN_ID_MASK), NULL, 0);
539 * sllin_configure_frame_cache() -- Configure particular entry in linfr_cache
542 * @cf: Pointer to CAN frame sent to this driver
543 * holding configuration information
545 static int sllin_configure_frame_cache(struct sllin *sl, struct can_frame *cf)
548 struct sllin_conf_entry *sce;
550 if (!(cf->can_id & LIN_CTRL_FRAME))
553 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
554 netdev_dbg(sl->dev, "Setting frame cache with EFF CAN frame. LIN ID = %d\n",
555 cf->can_id & LIN_ID_MASK);
557 spin_lock_irqsave(&sl->linfr_lock, flags);
559 sce->dlc = cf->can_dlc;
560 if (sce->dlc > SLLIN_DATA_MAX)
561 sce->dlc = SLLIN_DATA_MAX;
563 sce->frame_fl = (cf->can_id & ~LIN_ID_MASK) & CAN_EFF_MASK;
564 memcpy(sce->data, cf->data, cf->can_dlc);
566 spin_unlock_irqrestore(&sl->linfr_lock, flags);
572 * sllin_checksum() -- Count checksum for particular data
574 * @data: Pointer to the buffer containing whole LIN
575 * frame (i.e. including break and sync bytes).
576 * @length: Length of the buffer.
577 * @enhanced_fl: Flag determining whether Enhanced or Classic
578 * checksum should be counted.
580 static inline unsigned sllin_checksum(unsigned char *data, int length, int enhanced_fl)
590 for (; i < length; i++) {
599 #define SLLIN_STPMSG_RESPONLY (1) /* Message will be LIN Response only */
600 #define SLLIN_STPMSG_CHCKSUM_CLS (1 << 1)
601 #define SLLIN_STPMSG_CHCKSUM_ENH (1 << 2)
603 static int sllin_setup_msg(struct sllin *sl, int mode, int id,
604 unsigned char *data, int len)
606 if (id > LIN_ID_MASK)
609 if (!(mode & SLLIN_STPMSG_RESPONLY)) {
613 sl->rx_lim = SLLIN_BUFF_LEN;
616 sl->tx_buff[SLLIN_BUFF_BREAK] = 0;
617 sl->tx_buff[SLLIN_BUFF_SYNC] = 0x55;
618 sl->tx_buff[SLLIN_BUFF_ID] = id | sllin_id_parity_table[id];
619 sl->tx_lim = SLLIN_BUFF_DATA;
621 if ((data != NULL) && len) {
623 memcpy(sl->tx_buff + SLLIN_BUFF_DATA, data, len);
624 sl->tx_buff[sl->tx_lim] = sllin_checksum(sl->tx_buff,
625 sl->tx_lim, mode & SLLIN_STPMSG_CHCKSUM_ENH);
629 sl->rx_lim = SLLIN_BUFF_DATA + len + 1;
634 static void sllin_reset_buffs(struct sllin *sl)
638 sl->rx_lim = sl->lin_master ? 0 : SLLIN_BUFF_LEN;
641 sl->id_to_send = false;
642 sl->data_to_send = false;
646 * sllin_rx_validate() -- Validate received frame, i,e. check checksum
650 static int sllin_rx_validate(struct sllin *sl)
656 unsigned char rec_chcksm = sl->rx_buff[sl->rx_cnt - 1];
657 struct sllin_conf_entry *sce;
659 actual_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
660 sce = &sl->linfr_cache[actual_id];
662 spin_lock_irqsave(&sl->linfr_lock, flags);
664 ext_chcks_fl = sce->frame_fl & LIN_CHECKSUM_EXTENDED;
665 spin_unlock_irqrestore(&sl->linfr_lock, flags);
667 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1, ext_chcks_fl) !=
670 /* Type of checksum is configured for particular frame */
674 if (sllin_checksum(sl->rx_buff, sl->rx_cnt - 1,
675 !ext_chcks_fl) != rec_chcksm) {
684 static void sllin_slave_finish_rx_msg(struct sllin *sl)
686 if (sllin_rx_validate(sl) == -1) {
687 netdev_dbg(sl->dev, "sllin: RX validation failed.\n");
688 sllin_report_error(sl, LIN_ERR_CHECKSUM);
690 /* Send CAN non-RTR frame with data */
691 netdev_dbg(sl->dev, "sllin: sending NON-RTR CAN frame with LIN payload.");
692 sll_bump(sl); /* send packet to the network layer */
694 /* Prepare for reception of new header */
696 sl->rx_expect = SLLIN_BUFF_ID + 1;
697 sl->rx_len_unknown = false; /* We do know exact length of the header */
698 sl->header_received = false;
701 static void sllin_slave_receive_buf(struct tty_struct *tty,
702 const unsigned char *cp, char *fp, int count)
704 struct sllin *sl = (struct sllin *) tty->disc_data;
706 struct sllin_conf_entry *sce;
709 /* Read the characters out of the buffer */
713 * If we don't know the length of the current message
714 * we received the break of the next message.
715 * Evaluate the previous one before continuing
717 if (sl->rx_len_unknown == true)
719 hrtimer_cancel(&sl->rx_timer);
720 sllin_slave_finish_rx_msg(sl);
722 set_bit(SLF_RXEVENT, &sl->flags);
723 wake_up(&sl->kwt_wq);
726 netdev_dbg(sl->dev, "sllin_slave_receive_buf char 0x%02x ignored "
727 "due marker 0x%02x, flags 0x%lx\n",
728 *cp, *(fp-1), sl->flags);
732 sl->rx_expect = SLLIN_BUFF_ID + 1;
733 sl->rx_len_unknown = false; /* We do know exact length of the header */
734 sl->header_received = false;
737 if (sl->rx_cnt < SLLIN_BUFF_LEN) {
738 netdev_dbg(sl->dev, "LIN_RX[%d]: 0x%02x\n", sl->rx_cnt, *cp);
740 /* We did not receive break (0x00) character */
741 if ((sl->rx_cnt == SLLIN_BUFF_BREAK) && (*cp == 0x55)) {
742 sl->rx_buff[sl->rx_cnt++] = 0x00;
745 if (sl->rx_cnt == SLLIN_BUFF_SYNC) {
746 /* 'Duplicated' break character -- ignore */
752 /* Wrong sync character */
757 sl->rx_buff[sl->rx_cnt++] = *cp++;
760 /* Header received */
761 if ((sl->header_received == false) && (sl->rx_cnt >= (SLLIN_BUFF_ID + 1))) {
764 lin_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
765 sce = &sl->linfr_cache[lin_id];
767 spin_lock_irqsave(&sl->linfr_lock, flags);
769 sl->lin_state = SLSTATE_ID_RECEIVED;
770 /* Is the length of data set in frame cache? */
772 sl->rx_expect += sce->dlc + 1; /* + checksum */
773 sl->rx_len_unknown = false;
774 wake_up(&sl->kwt_wq);
776 sl->rx_expect += SLLIN_DATA_MAX + 1; /* + checksum */
777 sl->rx_len_unknown = true;
779 spin_unlock_irqrestore(&sl->linfr_lock, flags);
781 sl->header_received = true;
783 hrtimer_start(&sl->rx_timer,
784 ktime_add(ktime_get(), sl->rx_timer_timeout),
790 /* Response received */
791 if ((sl->header_received == true) &&
792 ((sl->rx_cnt >= sl->rx_expect))) {
794 hrtimer_cancel(&sl->rx_timer);
795 netdev_dbg(sl->dev, "Received LIN header & LIN response. "
796 "rx_cnt = %u, rx_expect = %u\n", sl->rx_cnt,
798 sllin_slave_finish_rx_msg(sl);
800 set_bit(SLF_RXEVENT, &sl->flags);
801 wake_up(&sl->kwt_wq);
806 static void sllin_receive_buf(struct tty_struct *tty,
807 const unsigned char *cp, char *fp, int count)
809 struct sllin *sl = (struct sllin *) tty->disc_data;
810 netdev_dbg(sl->dev, "sllin_receive_buf invoked, count = %u\n", count);
812 if (!sl || sl->magic != SLLIN_MAGIC || !netif_running(sl->dev))
816 sllin_master_receive_buf(tty, cp, fp, count);
818 sllin_slave_receive_buf(tty, cp, fp, count);
822 static int sllin_send_tx_buff(struct sllin *sl)
824 struct tty_struct *tty = sl->tty;
828 set_bit(SLF_TXBUFF_RQ, &sl->flags);
830 if (unlikely(test_and_set_bit(SLF_TXBUFF_INPR, &sl->flags)))
831 return 0; /* ongoing concurrent processing */
833 clear_bit(SLF_TXBUFF_RQ, &sl->flags);
834 smp_mb__after_clear_bit();
837 if (sl->lin_state != SLSTATE_BREAK_SENT)
838 remains = sl->tx_lim - sl->tx_cnt;
842 remains = sl->tx_lim - sl->tx_cnt;
845 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
853 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
854 res = tty->ops->write(tty, sl->tx_buff + sl->tx_cnt, remains);
856 clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
864 netdev_dbg(sl->dev, "sllin_send_tx_buff sent %d, remains %d\n",
865 sl->tx_cnt, remains);
867 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
868 smp_mb__after_clear_bit();
870 } while (unlikely(test_bit(SLF_TXBUFF_RQ, &sl->flags)));
875 clear_bit(SLF_TXBUFF_INPR, &sl->flags);
881 static int sllin_send_break(struct sllin *sl)
883 struct tty_struct *tty = sl->tty;
884 unsigned long break_baud;
887 break_baud = ((sl->lin_baud * 2) / 3);
888 sltty_change_speed(tty, break_baud);
890 tty->ops->flush_buffer(tty);
891 sl->rx_cnt = SLLIN_BUFF_BREAK;
893 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
894 sl->lin_state = SLSTATE_BREAK_SENT;
896 res = sllin_send_tx_buff(sl);
898 sl->lin_state = SLSTATE_IDLE;
904 #else /* BREAK_BY_BAUD */
906 static int sllin_send_break(struct sllin *sl)
908 struct tty_struct *tty = sl->tty;
910 unsigned long break_baud;
911 unsigned long usleep_range_min;
912 unsigned long usleep_range_max;
914 break_baud = ((sl->lin_baud * 2) / 3);
915 sl->rx_cnt = SLLIN_BUFF_BREAK;
916 sl->rx_expect = SLLIN_BUFF_BREAK + 1;
917 sl->lin_state = SLSTATE_BREAK_SENT;
919 /* Do the break ourselves; Inspired by
920 http://lxr.linux.no/#linux+v3.1.2/drivers/tty/tty_io.c#L2452 */
921 retval = tty->ops->break_ctl(tty, -1);
926 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR) / break_baud;
927 usleep_range_max = usleep_range_min + 50;
928 usleep_range(usleep_range_min, usleep_range_max);
930 retval = tty->ops->break_ctl(tty, 0);
931 usleep_range_min = (1000000l * 1 /* 1 bit */) / break_baud;
932 usleep_range_max = usleep_range_min + 30;
933 usleep_range(usleep_range_min, usleep_range_max);
935 tty->ops->flush_buffer(tty);
937 sl->tx_cnt = SLLIN_BUFF_SYNC;
939 netdev_dbg(sl->dev, "Break sent.\n");
940 set_bit(SLF_RXEVENT, &sl->flags);
941 wake_up(&sl->kwt_wq);
945 #endif /* BREAK_BY_BAUD */
948 static enum hrtimer_restart sllin_rx_timeout_handler(struct hrtimer *hrtimer)
950 struct sllin *sl = container_of(hrtimer, struct sllin, rx_timer);
953 * Signal timeout when:
954 * master: We did not receive as much characters as expected
955 * slave: * we did not receive any data bytes at all
956 * * we know the length and didn't receive enough
958 if ((sl->lin_master) ||
959 (sl->rx_cnt <= SLLIN_BUFF_DATA) ||
960 ((!sl->rx_len_unknown) &&
961 (sl->rx_cnt < sl->rx_expect))) {
962 sllin_report_error(sl, LIN_ERR_RX_TIMEOUT);
963 set_bit(SLF_TMOUTEVENT, &sl->flags);
965 sllin_slave_finish_rx_msg(sl);
966 set_bit(SLF_RXEVENT, &sl->flags);
968 wake_up(&sl->kwt_wq);
970 return HRTIMER_NORESTART;
973 /*****************************************
974 * sllin_kwthread - kernel worker thread
975 *****************************************/
977 static int sllin_kwthread(void *ptr)
979 struct sllin *sl = (struct sllin *)ptr;
980 struct tty_struct *tty = sl->tty;
981 struct sched_param schparam = { .sched_priority = 40 };
982 int tx_bytes = 0; /* Used for Network statistics */
985 struct sllin_conf_entry *sce;
987 netdev_dbg(sl->dev, "sllin_kwthread started.\n");
988 sched_setscheduler(current, SCHED_FIFO, &schparam);
990 clear_bit(SLF_ERROR, &sl->flags);
991 sltty_change_speed(tty, sl->lin_baud);
993 while (!kthread_should_stop()) {
994 struct can_frame *cf;
997 u8 lin_data_buff[SLLIN_DATA_MAX];
1000 if ((sl->lin_state == SLSTATE_IDLE) && sl->lin_master &&
1002 if (sllin_send_break(sl) < 0) {
1003 /* error processing */
1007 wait_event_killable(sl->kwt_wq, kthread_should_stop() ||
1008 test_bit(SLF_RXEVENT, &sl->flags) ||
1009 test_bit(SLF_TXEVENT, &sl->flags) ||
1010 test_bit(SLF_TMOUTEVENT, &sl->flags) ||
1011 test_bit(SLF_ERROR, &sl->flags) ||
1012 (sl->lin_state == SLSTATE_ID_RECEIVED) ||
1013 (((sl->lin_state == SLSTATE_IDLE) ||
1014 (sl->lin_state == SLSTATE_RESPONSE_WAIT))
1015 && test_bit(SLF_MSGEVENT, &sl->flags)));
1017 if (test_and_clear_bit(SLF_RXEVENT, &sl->flags)) {
1018 netdev_dbg(sl->dev, "sllin_kthread RXEVENT\n");
1021 if (test_and_clear_bit(SLF_ERROR, &sl->flags)) {
1022 unsigned long usleep_range_min;
1023 unsigned long usleep_range_max;
1024 hrtimer_cancel(&sl->rx_timer);
1025 netdev_dbg(sl->dev, "sllin_kthread ERROR\n");
1027 if (sl->lin_state != SLSTATE_IDLE)
1028 sllin_report_error(sl, LIN_ERR_FRAMING);
1030 usleep_range_min = (1000000l * SLLIN_SAMPLES_PER_CHAR * 10) /
1032 usleep_range_max = usleep_range_min + 50;
1033 usleep_range(usleep_range_min, usleep_range_max);
1034 sllin_reset_buffs(sl);
1035 sl->lin_state = SLSTATE_IDLE;
1038 if (test_and_clear_bit(SLF_TXEVENT, &sl->flags)) {
1039 netdev_dbg(sl->dev, "sllin_kthread TXEVENT\n");
1042 if (test_and_clear_bit(SLF_TMOUTEVENT, &sl->flags)) {
1043 netdev_dbg(sl->dev, "sllin_kthread TMOUTEVENT\n");
1044 sllin_reset_buffs(sl);
1046 sl->lin_state = SLSTATE_IDLE;
1049 switch (sl->lin_state) {
1051 if (!test_bit(SLF_MSGEVENT, &sl->flags))
1054 cf = (struct can_frame *)sl->tx_req_skb->data;
1056 /* SFF RTR CAN frame -> LIN header */
1057 if (cf->can_id & CAN_RTR_FLAG) {
1058 struct sllin_conf_entry *sce;
1060 netdev_dbg(sl->dev, "%s: RTR SFF CAN frame, ID = %x\n",
1061 __func__, cf->can_id & LIN_ID_MASK);
1063 sce = &sl->linfr_cache[cf->can_id & LIN_ID_MASK];
1064 spin_lock_irqsave(&sl->linfr_lock, flags);
1066 /* Is there Slave response in linfr_cache to be sent? */
1067 if ((sce->frame_fl & LIN_CACHE_RESPONSE)
1068 && (sce->dlc > 0)) {
1070 netdev_dbg(sl->dev, "Sending LIN response from linfr_cache\n");
1072 lin_data = sce->data;
1074 if (lin_dlc > SLLIN_DATA_MAX)
1075 lin_dlc = SLLIN_DATA_MAX;
1076 memcpy(lin_data_buff, lin_data, lin_dlc);
1077 lin_data = lin_data_buff;
1082 spin_unlock_irqrestore(&sl->linfr_lock, flags);
1084 } else { /* SFF NON-RTR CAN frame -> LIN header + LIN response */
1085 netdev_dbg(sl->dev, "%s: NON-RTR SFF CAN frame, ID = %x\n",
1086 __func__, (int)cf->can_id & LIN_ID_MASK);
1088 lin_data = cf->data;
1089 lin_dlc = cf->can_dlc;
1090 if (lin_dlc > SLLIN_DATA_MAX)
1091 lin_dlc = SLLIN_DATA_MAX;
1095 if (sllin_setup_msg(sl, 0, cf->can_id & LIN_ID_MASK,
1096 lin_data, lin_dlc) != -1) {
1098 sl->id_to_send = true;
1099 sl->data_to_send = (lin_data != NULL) ? true : false;
1100 sl->resp_len_known = (lin_dlc > 0) ? true : false;
1101 sl->dev->stats.tx_packets++;
1102 sl->dev->stats.tx_bytes += tx_bytes;
1105 clear_bit(SLF_MSGEVENT, &sl->flags);
1106 kfree_skb(sl->tx_req_skb);
1107 netif_wake_queue(sl->dev);
1108 hrtimer_start(&sl->rx_timer,
1109 ktime_add(ktime_get(), sl->rx_timer_timeout),
1113 case SLSTATE_BREAK_SENT:
1114 #ifdef BREAK_BY_BAUD
1115 if (sl->rx_cnt <= SLLIN_BUFF_BREAK)
1118 res = sltty_change_speed(tty, sl->lin_baud);
1121 sl->lin_state = SLSTATE_ID_SENT;
1122 sllin_send_tx_buff(sl);
1125 case SLSTATE_ID_SENT:
1126 hrtimer_cancel(&sl->rx_timer);
1127 sl->id_to_send = false;
1128 if (sl->data_to_send) {
1129 sllin_send_tx_buff(sl);
1130 sl->lin_state = SLSTATE_RESPONSE_SENT;
1131 sl->rx_expect = sl->tx_lim;
1132 goto slstate_response_sent;
1134 if (sl->resp_len_known) {
1135 sl->rx_expect = sl->rx_lim;
1137 sl->rx_expect = SLLIN_BUFF_DATA + 2;
1139 sl->lin_state = SLSTATE_RESPONSE_WAIT;
1140 /* If we don't receive anything, timer will "unblock" us */
1141 hrtimer_start(&sl->rx_timer,
1142 ktime_add(ktime_get(), sl->rx_timer_timeout),
1144 goto slstate_response_wait;
1148 case SLSTATE_RESPONSE_WAIT:
1149 slstate_response_wait:
1150 if (test_bit(SLF_MSGEVENT, &sl->flags)) {
1151 unsigned char *lin_buff;
1152 cf = (struct can_frame *)sl->tx_req_skb->data;
1154 lin_buff = (sl->lin_master) ? sl->tx_buff : sl->rx_buff;
1155 if (cf->can_id == (lin_buff[SLLIN_BUFF_ID] & LIN_ID_MASK)) {
1156 hrtimer_cancel(&sl->rx_timer);
1157 netdev_dbg(sl->dev, "received LIN response in a CAN frame.\n");
1158 if (sllin_setup_msg(sl, SLLIN_STPMSG_RESPONLY,
1159 cf->can_id & LIN_ID_MASK,
1160 cf->data, cf->can_dlc) != -1) {
1162 sl->rx_expect = sl->tx_lim;
1163 sl->data_to_send = true;
1164 sl->dev->stats.tx_packets++;
1165 sl->dev->stats.tx_bytes += tx_bytes;
1167 if (!sl->lin_master) {
1168 sl->tx_cnt = SLLIN_BUFF_DATA;
1171 sllin_send_tx_buff(sl);
1172 clear_bit(SLF_MSGEVENT, &sl->flags);
1173 kfree_skb(sl->tx_req_skb);
1174 netif_wake_queue(sl->dev);
1176 sl->lin_state = SLSTATE_RESPONSE_SENT;
1177 goto slstate_response_sent;
1180 sl->lin_state = SLSTATE_RESPONSE_WAIT_BUS;
1184 /* Be aware, no BREAK here */
1185 case SLSTATE_RESPONSE_WAIT_BUS:
1186 if (sl->rx_cnt < sl->rx_expect)
1189 hrtimer_cancel(&sl->rx_timer);
1190 netdev_dbg(sl->dev, "response received ID %d len %d\n",
1191 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1193 if (sllin_rx_validate(sl) == -1) {
1194 netdev_dbg(sl->dev, "RX validation failed.\n");
1195 sllin_report_error(sl, LIN_ERR_CHECKSUM);
1197 /* Send CAN non-RTR frame with data */
1198 netdev_dbg(sl->dev, "sending NON-RTR CAN frame with LIN payload.");
1199 sll_bump(sl); /* send packet to the network layer */
1202 sl->id_to_send = false;
1203 sl->lin_state = SLSTATE_IDLE;
1206 case SLSTATE_ID_RECEIVED:
1207 lin_id = sl->rx_buff[SLLIN_BUFF_ID] & LIN_ID_MASK;
1208 sce = &sl->linfr_cache[lin_id];
1209 spin_lock_irqsave(&sl->linfr_lock, flags);
1211 if ((sce->frame_fl & LIN_CACHE_RESPONSE)
1212 && (sce->dlc > 0)) {
1215 netdev_dbg(sl->dev, "Sending LIN response from linfr_cache\n");
1217 lin_data = sce->data;
1219 if (lin_dlc > SLLIN_DATA_MAX)
1220 lin_dlc = SLLIN_DATA_MAX;
1221 memcpy(lin_data_buff, lin_data, lin_dlc);
1222 lin_data = lin_data_buff;
1225 mode = SLLIN_STPMSG_RESPONLY;
1226 if (sce->frame_fl & LIN_CHECKSUM_EXTENDED)
1227 mode |= SLLIN_STPMSG_CHCKSUM_ENH;
1229 if (sllin_setup_msg(sl, mode, lin_id & LIN_ID_MASK,
1230 lin_data, lin_dlc) != -1) {
1232 sl->rx_expect = sl->tx_lim;
1233 sl->data_to_send = true;
1234 sl->dev->stats.tx_packets++;
1235 sl->dev->stats.tx_bytes += tx_bytes;
1236 sl->resp_len_known = true;
1238 if (!sl->lin_master) {
1239 sl->tx_cnt = SLLIN_BUFF_DATA;
1241 sllin_send_tx_buff(sl);
1244 hrtimer_start(&sl->rx_timer,
1245 ktime_add(ktime_get(), sl->rx_timer_timeout),
1248 spin_unlock_irqrestore(&sl->linfr_lock, flags);
1249 sl->lin_state = SLSTATE_IDLE;
1252 case SLSTATE_RESPONSE_SENT:
1253 slstate_response_sent:
1254 if (sl->rx_cnt < sl->tx_lim)
1257 hrtimer_cancel(&sl->rx_timer);
1258 sll_bump(sl); /* send packet to the network layer */
1259 netdev_dbg(sl->dev, "response sent ID %d len %d\n",
1260 sl->rx_buff[SLLIN_BUFF_ID], sl->rx_cnt - SLLIN_BUFF_DATA - 1);
1262 sl->id_to_send = false;
1263 sl->lin_state = SLSTATE_IDLE;
1268 hrtimer_cancel(&sl->rx_timer);
1269 netdev_dbg(sl->dev, "sllin_kwthread stopped.\n");
1275 /************************************
1276 * sllin_open helper routines.
1277 ************************************/
1279 /* Collect hanged up channels */
1280 static void sll_sync(void)
1283 struct net_device *dev;
1286 for (i = 0; i < maxdev; i++) {
1287 dev = sllin_devs[i];
1291 sl = netdev_priv(dev);
1294 if (dev->flags & IFF_UP)
1299 /* Find a free SLLIN channel, and link in this `tty' line. */
1300 static struct sllin *sll_alloc(dev_t line)
1303 struct net_device *dev = NULL;
1306 if (sllin_devs == NULL)
1307 return NULL; /* Master array missing ! */
1309 for (i = 0; i < maxdev; i++) {
1310 dev = sllin_devs[i];
1316 /* Sorry, too many, all slots in use */
1321 sl = netdev_priv(dev);
1322 if (test_bit(SLF_INUSE, &sl->flags)) {
1323 unregister_netdevice(dev);
1325 sllin_devs[i] = NULL;
1330 char name[IFNAMSIZ];
1331 sprintf(name, "sllin%d", i);
1333 dev = alloc_netdev(sizeof(*sl), name, sll_setup);
1339 sl = netdev_priv(dev);
1340 /* Initialize channel control data */
1341 sl->magic = SLLIN_MAGIC;
1343 spin_lock_init(&sl->lock);
1344 spin_lock_init(&sl->linfr_lock);
1345 sllin_devs[i] = dev;
1351 * Open the high-level part of the SLLIN channel.
1352 * This function is called by the TTY module when the
1353 * SLLIN line discipline is called for. Because we are
1354 * sure the tty line exists, we only have to link it to
1355 * a free SLLIN channel...
1357 * Called in process context serialized from other ldisc calls.
1360 static int sllin_open(struct tty_struct *tty)
1365 pr_debug("sllin: %s() invoked\n", __func__);
1367 if (!capable(CAP_NET_ADMIN))
1370 if (tty->ops->write == NULL)
1373 /* RTnetlink lock is misused here to serialize concurrent
1374 opens of sllin channels. There are better ways, but it is
1379 /* Collect hanged up channels. */
1382 sl = tty->disc_data;
1385 /* First make sure we're not already connected. */
1386 if (sl && sl->magic == SLLIN_MAGIC)
1389 /* OK. Find a free SLLIN channel to use. */
1391 sl = sll_alloc(tty_devnum(tty));
1396 tty->disc_data = sl;
1397 sl->line = tty_devnum(tty);
1399 if (!test_bit(SLF_INUSE, &sl->flags)) {
1400 /* Perform the low-level SLLIN initialization. */
1401 sl->lin_master = master;
1403 pr_debug("sllin: Configured as MASTER\n");
1405 pr_debug("sllin: Configured as SLAVE\n");
1407 sllin_reset_buffs(sl);
1409 sl->lin_baud = (baudrate == 0) ? LIN_DEFAULT_BAUDRATE : baudrate;
1410 pr_debug("sllin: Baudrate set to %u\n", sl->lin_baud);
1412 sl->lin_state = SLSTATE_IDLE;
1414 hrtimer_init(&sl->rx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1415 sl->rx_timer.function = sllin_rx_timeout_handler;
1416 /* timeval_to_ktime(msg_head->ival1); */
1417 sl->rx_timer_timeout = ns_to_ktime(
1418 (1000000000l / sl->lin_baud) *
1419 SLLIN_SAMPLES_PER_CHAR * SLLIN_CHARS_TO_TIMEOUT);
1421 set_bit(SLF_INUSE, &sl->flags);
1423 init_waitqueue_head(&sl->kwt_wq);
1424 sl->kwthread = kthread_run(sllin_kwthread, sl, "sllin");
1425 if (sl->kwthread == NULL)
1428 err = register_netdevice(sl->dev);
1430 goto err_free_chan_and_thread;
1433 /* Done. We have linked the TTY line to a channel. */
1435 tty->receive_room = SLLIN_BUFF_LEN * 40; /* We don't flow control */
1437 /* TTY layer expects 0 on success */
1440 err_free_chan_and_thread:
1441 kthread_stop(sl->kwthread);
1442 sl->kwthread = NULL;
1446 tty->disc_data = NULL;
1447 clear_bit(SLF_INUSE, &sl->flags);
1452 /* Count references from TTY module */
1457 * Close down a SLLIN channel.
1458 * This means flushing out any pending queues, and then returning. This
1459 * call is serialized against other ldisc functions.
1461 * We also use this method for a hangup event.
1464 static void sllin_close(struct tty_struct *tty)
1466 struct sllin *sl = (struct sllin *) tty->disc_data;
1468 /* First make sure we're connected. */
1469 if (!sl || sl->magic != SLLIN_MAGIC || sl->tty != tty)
1472 kthread_stop(sl->kwthread);
1473 sl->kwthread = NULL;
1475 tty->disc_data = NULL;
1478 /* Flush network side */
1479 unregister_netdev(sl->dev);
1480 /* This will complete via sl_free_netdev */
1483 static int sllin_hangup(struct tty_struct *tty)
1489 /* Perform I/O control on an active SLLIN channel. */
1490 static int sllin_ioctl(struct tty_struct *tty, struct file *file,
1491 unsigned int cmd, unsigned long arg)
1493 struct sllin *sl = (struct sllin *) tty->disc_data;
1496 /* First make sure we're connected. */
1497 if (!sl || sl->magic != SLLIN_MAGIC)
1502 tmp = strlen(sl->dev->name) + 1;
1503 if (copy_to_user((void __user *)arg, sl->dev->name, tmp))
1511 return tty_mode_ioctl(tty, file, cmd, arg);
1515 static struct tty_ldisc_ops sll_ldisc = {
1516 .owner = THIS_MODULE,
1517 .magic = TTY_LDISC_MAGIC,
1520 .close = sllin_close,
1521 .hangup = sllin_hangup,
1522 .ioctl = sllin_ioctl,
1523 .receive_buf = sllin_receive_buf,
1524 .write_wakeup = sllin_write_wakeup,
1527 static int __init sllin_init(void)
1532 maxdev = 4; /* Sanity */
1535 pr_debug("sllin: %d dynamic interface channels.\n", maxdev);
1537 sllin_devs = kzalloc(sizeof(struct net_device *)*maxdev, GFP_KERNEL);
1539 pr_err("sllin: can't allocate sllin device array!\n");
1543 /* Fill in our line protocol discipline, and register it */
1544 status = tty_register_ldisc(N_SLLIN, &sll_ldisc);
1546 pr_err("sllin: can't register line discipline\n");
1550 #ifdef BREAK_BY_BAUD
1551 pr_debug("sllin: Break is generated by baud-rate change.");
1553 pr_debug("sllin: Break is generated manually with tiny sleep.");
1559 static void __exit sllin_exit(void)
1562 struct net_device *dev;
1564 unsigned long timeout = jiffies + HZ;
1567 if (sllin_devs == NULL)
1570 /* First of all: check for active disciplines and hangup them.
1574 msleep_interruptible(100);
1577 for (i = 0; i < maxdev; i++) {
1578 dev = sllin_devs[i];
1581 sl = netdev_priv(dev);
1582 spin_lock_bh(&sl->lock);
1585 tty_hangup(sl->tty);
1587 spin_unlock_bh(&sl->lock);
1589 } while (busy && time_before(jiffies, timeout));
1591 /* FIXME: hangup is async so we should wait when doing this second
1594 for (i = 0; i < maxdev; i++) {
1595 dev = sllin_devs[i];
1598 sllin_devs[i] = NULL;
1600 sl = netdev_priv(dev);
1602 netdev_dbg(sl->dev, "tty discipline still running\n");
1603 /* Intentionally leak the control block. */
1604 dev->destructor = NULL;
1607 unregister_netdev(dev);
1613 i = tty_unregister_ldisc(N_SLLIN);
1615 pr_err("sllin: can't unregister ldisc (err %d)\n", i);
1618 module_init(sllin_init);
1619 module_exit(sllin_exit);