4 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
5 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
6 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the version 2 of the GNU General Public License
10 * as published by the Free Software Foundation
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/module.h>
23 #include <linux/version.h>
24 #include <linux/kernel.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <socketcan/can.h>
28 #include <socketcan/can/dev.h>
29 #ifndef CONFIG_CAN_DEV_SYSFS
30 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,24)
31 #error "CAN netlink interface not support by this kernel version"
33 #include <socketcan/can/netlink.h>
34 #include <net/rtnetlink.h>
36 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,21)
37 #error "CAN sysfs interface not support by this kernel version"
42 #define MOD_DESC "CAN device driver interface"
44 MODULE_DESCRIPTION(MOD_DESC);
45 MODULE_LICENSE("GPL v2");
46 MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
48 #ifdef CONFIG_CAN_CALC_BITTIMING
49 #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
52 * Bit-timing calculation derived from:
54 * Code based on LinCAN sources and H8S2638 project
55 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
56 * Copyright 2005 Stanislav Marek
57 * email: pisa@cmp.felk.cvut.cz
59 * Calculates proper bit-timing parameters for a specified bit-rate
60 * and sample-point, which can then be used to set the bit-timing
61 * registers of the CAN controller. You can find more information
62 * in the header file socketcan/can/netlink.h.
64 static int can_update_spt(const struct can_bittiming_const *btc,
65 int sampl_pt, int tseg, int *tseg1, int *tseg2)
67 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
68 if (*tseg2 < btc->tseg2_min)
69 *tseg2 = btc->tseg2_min;
70 if (*tseg2 > btc->tseg2_max)
71 *tseg2 = btc->tseg2_max;
72 *tseg1 = tseg - *tseg2;
73 if (*tseg1 > btc->tseg1_max) {
74 *tseg1 = btc->tseg1_max;
75 *tseg2 = tseg - *tseg1;
77 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
80 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
82 struct can_priv *priv = netdev_priv(dev);
83 const struct can_bittiming_const *btc = priv->bittiming_const;
84 long rate, best_rate = 0;
85 long best_error = 1000000000, error = 0;
86 int best_tseg = 0, best_brp = 0, brp = 0;
87 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
88 int spt_error = 1000, spt = 0, sampl_pt;
91 if (!priv->bittiming_const)
94 /* Use CIA recommended sample points */
95 if (bt->sample_point) {
96 sampl_pt = bt->sample_point;
98 if (bt->bitrate > 800000)
100 else if (bt->bitrate > 500000)
106 /* tseg even = round down, odd = round up */
107 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
108 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
109 tsegall = 1 + tseg / 2;
110 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
111 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
112 /* chose brp step which is possible in system */
113 brp = (brp / btc->brp_inc) * btc->brp_inc;
114 if ((brp < btc->brp_min) || (brp > btc->brp_max))
116 rate = priv->clock.freq / (brp * tsegall);
117 error = bt->bitrate - rate;
118 /* tseg brp biterror */
121 if (error > best_error)
125 spt = can_update_spt(btc, sampl_pt, tseg / 2,
127 error = sampl_pt - spt;
130 if (error > spt_error)
134 best_tseg = tseg / 2;
142 /* Error in one-tenth of a percent */
143 error = (best_error * 1000) / bt->bitrate;
144 if (error > CAN_CALC_MAX_ERROR) {
146 "bitrate error %ld.%ld%% too high\n",
147 error / 10, error % 10);
150 dev_warn(ND2D(dev), "bitrate error %ld.%ld%%\n",
151 error / 10, error % 10);
155 spt = can_update_spt(btc, sampl_pt, best_tseg, &tseg1, &tseg2);
157 v64 = (u64)best_brp * 1000000000UL;
158 do_div(v64, priv->clock.freq);
160 bt->prop_seg = tseg1 / 2;
161 bt->phase_seg1 = tseg1 - bt->prop_seg;
162 bt->phase_seg2 = tseg2;
165 #ifndef CONFIG_CAN_DEV_SYSFS
167 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
168 /* real sample point */
169 bt->sample_point = spt;
173 #else /* !CONFIG_CAN_CALC_BITTIMING */
174 static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
176 dev_err(ND2D(dev), "bit-timing calculation not available\n");
179 #endif /* CONFIG_CAN_CALC_BITTIMING */
182 #ifdef CONFIG_CAN_DEV_SYSFS
183 int can_sample_point(struct can_bittiming *bt)
185 return ((bt->prop_seg + bt->phase_seg1 + 1) * 1000) /
186 (bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1);
191 * Checks the validity of the specified bit-timing parameters prop_seg,
192 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
193 * prescaler value brp. You can find more information in the header
194 * file socketcan/can/netlink.h.
196 static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
198 struct can_priv *priv = netdev_priv(dev);
199 const struct can_bittiming_const *btc = priv->bittiming_const;
203 if (!priv->bittiming_const)
206 tseg1 = bt->prop_seg + bt->phase_seg1;
209 if (bt->sjw > btc->sjw_max ||
210 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
211 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
214 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
215 if (btc->brp_inc > 1)
216 do_div(brp64, btc->brp_inc);
217 brp64 += 500000000UL - 1;
218 do_div(brp64, 1000000000UL); /* the practicable BRP */
219 if (btc->brp_inc > 1)
220 brp64 *= btc->brp_inc;
221 bt->brp = (u32)brp64;
223 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
226 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
227 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
228 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
233 int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
235 struct can_priv *priv = netdev_priv(dev);
238 /* Check if the CAN device has bit-timing parameters */
239 if (priv->bittiming_const) {
241 /* Non-expert mode? Check if the bitrate has been pre-defined */
243 /* Determine bit-timing parameters */
244 err = can_calc_bittiming(dev, bt);
246 /* Check bit-timing params and calculate proper brp */
247 err = can_fixup_bittiming(dev, bt);
256 * Local echo of CAN messages
258 * CAN network devices *should* support a local echo functionality
259 * (see Documentation/networking/can.txt). To test the handling of CAN
260 * interfaces that do not support the local echo both driver types are
261 * implemented. In the case that the driver does not support the echo
262 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
263 * to perform the echo as a fallback solution.
265 static void can_flush_echo_skb(struct net_device *dev)
267 struct can_priv *priv = netdev_priv(dev);
268 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
269 struct net_device_stats *stats = can_get_stats(dev);
271 struct net_device_stats *stats = &dev->stats;
275 for (i = 0; i < CAN_ECHO_SKB_MAX; i++) {
276 if (priv->echo_skb[i]) {
277 kfree_skb(priv->echo_skb[i]);
278 priv->echo_skb[i] = NULL;
280 stats->tx_aborted_errors++;
286 * Put the skb on the stack to be looped backed locally lateron
288 * The function is typically called in the start_xmit function
289 * of the device driver. The driver must protect access to
290 * priv->echo_skb, if necessary.
292 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx)
294 struct can_priv *priv = netdev_priv(dev);
296 /* check flag whether this packet has to be looped back */
297 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
302 if (!priv->echo_skb[idx]) {
303 struct sock *srcsk = skb->sk;
305 if (atomic_read(&skb->users) != 1) {
306 struct sk_buff *old_skb = skb;
308 skb = skb_clone(old_skb, GFP_ATOMIC);
317 /* make settings for echo to reduce code in irq context */
318 skb->protocol = htons(ETH_P_CAN);
319 skb->pkt_type = PACKET_BROADCAST;
320 skb->ip_summed = CHECKSUM_UNNECESSARY;
323 /* save this skb for tx interrupt echo handling */
324 priv->echo_skb[idx] = skb;
326 /* locking problem with netif_stop_queue() ?? */
327 dev_err(ND2D(dev), "%s: BUG! echo_skb is occupied!\n",
332 EXPORT_SYMBOL_GPL(can_put_echo_skb);
335 * Get the skb from the stack and loop it back locally
337 * The function is typically called when the TX done interrupt
338 * is handled in the device driver. The driver must protect
339 * access to priv->echo_skb, if necessary.
341 void can_get_echo_skb(struct net_device *dev, int idx)
343 struct can_priv *priv = netdev_priv(dev);
345 if (priv->echo_skb[idx]) {
346 netif_rx(priv->echo_skb[idx]);
347 priv->echo_skb[idx] = NULL;
350 EXPORT_SYMBOL_GPL(can_get_echo_skb);
353 * Remove the skb from the stack and free it.
355 * The function is typically called when TX failed.
357 void can_free_echo_skb(struct net_device *dev, int idx)
359 struct can_priv *priv = netdev_priv(dev);
361 if (priv->echo_skb[idx]) {
362 kfree_skb(priv->echo_skb[idx]);
363 priv->echo_skb[idx] = NULL;
366 EXPORT_SYMBOL_GPL(can_free_echo_skb);
369 * CAN device restart for bus-off recovery
371 void can_restart(unsigned long data)
373 struct net_device *dev = (struct net_device *)data;
374 struct can_priv *priv = netdev_priv(dev);
375 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
376 struct net_device_stats *stats = can_get_stats(dev);
378 struct net_device_stats *stats = &dev->stats;
381 struct can_frame *cf;
384 BUG_ON(netif_carrier_ok(dev));
387 * No synchronization needed because the device is bus-off and
388 * no messages can come in or go out.
390 can_flush_echo_skb(dev);
392 /* send restart message upstream */
393 skb = dev_alloc_skb(sizeof(struct can_frame));
399 skb->protocol = htons(ETH_P_CAN);
400 cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
401 memset(cf, 0, sizeof(struct can_frame));
402 cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
403 cf->can_dlc = CAN_ERR_DLC;
407 dev->last_rx = jiffies;
409 stats->rx_bytes += cf->can_dlc;
412 dev_dbg(ND2D(dev), "restarted\n");
413 priv->can_stats.restarts++;
415 /* Now restart the device */
416 err = priv->do_set_mode(dev, CAN_MODE_START);
418 netif_carrier_on(dev);
420 dev_err(ND2D(dev), "Error %d during restart", err);
423 int can_restart_now(struct net_device *dev)
425 struct can_priv *priv = netdev_priv(dev);
428 * A manual restart is only permitted if automatic restart is
429 * disabled and the device is in the bus-off state
431 if (priv->restart_ms)
433 if (priv->state != CAN_STATE_BUS_OFF)
436 /* Runs as soon as possible in the timer context */
437 mod_timer(&priv->restart_timer, jiffies);
445 * This functions should be called when the device goes bus-off to
446 * tell the netif layer that no more packets can be sent or received.
447 * If enabled, a timer is started to trigger bus-off recovery.
449 void can_bus_off(struct net_device *dev)
451 struct can_priv *priv = netdev_priv(dev);
453 dev_dbg(ND2D(dev), "bus-off\n");
455 netif_carrier_off(dev);
456 priv->can_stats.bus_off++;
458 if (priv->restart_ms)
459 mod_timer(&priv->restart_timer,
460 jiffies + (priv->restart_ms * HZ) / 1000);
462 EXPORT_SYMBOL_GPL(can_bus_off);
464 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
465 struct net_device_stats *can_get_stats(struct net_device *dev)
467 struct can_priv *priv = netdev_priv(dev);
469 return &priv->net_stats;
471 EXPORT_SYMBOL_GPL(can_get_stats);
474 static void can_setup(struct net_device *dev)
476 dev->type = ARPHRD_CAN;
477 dev->mtu = sizeof(struct can_frame);
478 dev->hard_header_len = 0;
480 dev->tx_queue_len = 10;
482 /* New-style flags. */
483 dev->flags = IFF_NOARP;
484 dev->features = NETIF_F_NO_CSUM;
485 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
486 dev->get_stats = can_get_stats;
491 * Allocate and setup space for the CAN network device
493 struct net_device *alloc_candev(int sizeof_priv)
495 struct net_device *dev;
496 struct can_priv *priv;
498 dev = alloc_netdev(sizeof_priv, "can%d", can_setup);
502 priv = netdev_priv(dev);
504 priv->state = CAN_STATE_STOPPED;
506 init_timer(&priv->restart_timer);
510 EXPORT_SYMBOL_GPL(alloc_candev);
513 * Free space of the CAN network device
515 void free_candev(struct net_device *dev)
519 EXPORT_SYMBOL_GPL(free_candev);
521 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15)
522 static inline void setup_timer(struct timer_list * timer,
523 void (*function)(unsigned long),
526 timer->function = function;
533 * Common open function when the device gets opened.
535 * This function should be called in the open function of the device
538 int open_candev(struct net_device *dev)
540 struct can_priv *priv = netdev_priv(dev);
541 #ifdef CONFIG_CAN_DEV_SYSFS
545 if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
546 dev_err(ND2D(dev), "bit-timing not yet defined\n");
550 #ifdef CONFIG_CAN_DEV_SYSFS
551 err = can_get_bittiming(dev, &priv->bittiming);
555 if (priv->do_set_bittiming) {
556 /* Finally, set the bit-timing registers */
557 err = priv->do_set_bittiming(dev);
563 /* Switch carrier on if device was stopped while in bus-off state */
564 if (!netif_carrier_ok(dev))
565 netif_carrier_on(dev);
567 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
571 EXPORT_SYMBOL_GPL(open_candev);
574 * Common close function for cleanup before the device gets closed.
576 * This function should be called in the close function of the device
579 void close_candev(struct net_device *dev)
581 struct can_priv *priv = netdev_priv(dev);
583 if (del_timer_sync(&priv->restart_timer))
585 can_flush_echo_skb(dev);
587 EXPORT_SYMBOL_GPL(close_candev);
589 #ifndef CONFIG_CAN_DEV_SYSFS
591 * CAN netlink interface
593 static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
594 [IFLA_CAN_STATE] = { .type = NLA_U32 },
595 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
596 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
597 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
598 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
599 [IFLA_CAN_BITTIMING_CONST]
600 = { .len = sizeof(struct can_bittiming_const) },
601 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
604 static int can_changelink(struct net_device *dev,
605 struct nlattr *tb[], struct nlattr *data[])
607 struct can_priv *priv = netdev_priv(dev);
610 /* We need synchronization with dev->stop() */
613 if (data[IFLA_CAN_CTRLMODE]) {
614 struct can_ctrlmode *cm;
616 /* Do not allow changing controller mode while running */
617 if (dev->flags & IFF_UP)
619 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
620 priv->ctrlmode &= ~cm->mask;
621 priv->ctrlmode |= cm->flags;
624 if (data[IFLA_CAN_BITTIMING]) {
625 struct can_bittiming bt;
627 /* Do not allow changing bittiming while running */
628 if (dev->flags & IFF_UP)
630 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
631 if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
633 err = can_get_bittiming(dev, &bt);
636 memcpy(&priv->bittiming, &bt, sizeof(bt));
638 if (priv->do_set_bittiming) {
639 /* Finally, set the bit-timing registers */
640 err = priv->do_set_bittiming(dev);
646 if (data[IFLA_CAN_RESTART_MS]) {
647 /* Do not allow changing restart delay while running */
648 if (dev->flags & IFF_UP)
650 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
653 if (data[IFLA_CAN_RESTART]) {
654 /* Do not allow a restart while not running */
655 if (!(dev->flags & IFF_UP))
657 err = can_restart_now(dev);
665 static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
667 struct can_priv *priv = netdev_priv(dev);
668 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
669 enum can_state state = priv->state;
671 if (priv->do_get_state)
672 priv->do_get_state(dev, &state);
673 NLA_PUT_U32(skb, IFLA_CAN_STATE, state);
674 NLA_PUT(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm);
675 NLA_PUT_U32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms);
676 NLA_PUT(skb, IFLA_CAN_BITTIMING,
677 sizeof(priv->bittiming), &priv->bittiming);
678 NLA_PUT(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock);
679 if (priv->bittiming_const)
680 NLA_PUT(skb, IFLA_CAN_BITTIMING_CONST,
681 sizeof(*priv->bittiming_const), priv->bittiming_const);
689 static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
691 struct can_priv *priv = netdev_priv(dev);
693 NLA_PUT(skb, IFLA_INFO_XSTATS,
694 sizeof(priv->can_stats), &priv->can_stats);
702 static int can_newlink(struct net_device *dev,
703 struct nlattr *tb[], struct nlattr *data[])
708 static struct rtnl_link_ops can_link_ops __read_mostly = {
710 .maxtype = IFLA_CAN_MAX,
711 .policy = can_policy,
713 .newlink = can_newlink,
714 .changelink = can_changelink,
715 .fill_info = can_fill_info,
716 .fill_xstats = can_fill_xstats,
719 #endif /* !CONFIG_CAN_DEV_SYSFS */
722 * Register the CAN network device
724 int register_candev(struct net_device *dev)
726 #ifdef CONFIG_CAN_DEV_SYSFS
729 err = register_netdev(dev);
731 can_create_sysfs(dev);
735 dev->rtnl_link_ops = &can_link_ops;
736 return register_netdev(dev);
739 EXPORT_SYMBOL_GPL(register_candev);
742 * Unregister the CAN network device
744 void unregister_candev(struct net_device *dev)
746 #ifdef CONFIG_CAN_DEV_SYSFS
747 can_remove_sysfs(dev);
749 unregister_netdev(dev);
751 EXPORT_SYMBOL_GPL(unregister_candev);
753 static __init int can_dev_init(void)
755 #ifndef CONFIG_CAN_DEV_SYSFS
758 err = rtnl_link_register(&can_link_ops);
760 printk(KERN_INFO MOD_DESC "\n");
764 printk(KERN_INFO MOD_DESC " using the deprecated SYSFS interface\n");
769 module_init(can_dev_init);
771 static __exit void can_dev_exit(void)
773 #ifndef CONFIG_CAN_DEV_SYSFS
774 rtnl_link_unregister(&can_link_ops);
777 module_exit(can_dev_exit);
779 #ifndef CONFIG_CAN_DEV_SYSFS
780 MODULE_ALIAS_RTNL_LINK("can");