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1/*
2 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
3 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
4 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the version 2 of the GNU General Public License
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/module.h>
20#include <linux/kernel.h>
21#include <linux/slab.h>
22#include <linux/netdevice.h>
23#include <linux/if_arp.h>
24#include <linux/can.h>
25#include <linux/can/dev.h>
26#include <linux/can/skb.h>
27#include <linux/can/netlink.h>
28#include <linux/can/led.h>
29#include <net/rtnetlink.h>
30
31#define MOD_DESC "CAN device driver interface"
32
33MODULE_DESCRIPTION(MOD_DESC);
34MODULE_LICENSE("GPL v2");
35MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
36
37/* CAN DLC to real data length conversion helpers */
38
39static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
40 8, 12, 16, 20, 24, 32, 48, 64};
41
42/* get data length from can_dlc with sanitized can_dlc */
43u8 can_dlc2len(u8 can_dlc)
44{
45 return dlc2len[can_dlc & 0x0F];
46}
47EXPORT_SYMBOL_GPL(can_dlc2len);
48
49static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, /* 0 - 8 */
50 9, 9, 9, 9, /* 9 - 12 */
51 10, 10, 10, 10, /* 13 - 16 */
52 11, 11, 11, 11, /* 17 - 20 */
53 12, 12, 12, 12, /* 21 - 24 */
54 13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
55 14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
56 14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
57 15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
58 15, 15, 15, 15, 15, 15, 15, 15}; /* 57 - 64 */
59
60/* map the sanitized data length to an appropriate data length code */
61u8 can_len2dlc(u8 len)
62{
63 if (unlikely(len > 64))
64 return 0xF;
65
66 return len2dlc[len];
67}
68EXPORT_SYMBOL_GPL(can_len2dlc);
69
70#ifdef CONFIG_CAN_CALC_BITTIMING
71#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
72
73/*
74 * Bit-timing calculation derived from:
75 *
76 * Code based on LinCAN sources and H8S2638 project
77 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
78 * Copyright 2005 Stanislav Marek
79 * email: pisa@cmp.felk.cvut.cz
80 *
81 * Calculates proper bit-timing parameters for a specified bit-rate
82 * and sample-point, which can then be used to set the bit-timing
83 * registers of the CAN controller. You can find more information
84 * in the header file linux/can/netlink.h.
85 */
86static int can_update_spt(const struct can_bittiming_const *btc,
87 int sampl_pt, int tseg, int *tseg1, int *tseg2)
88{
89 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
90 if (*tseg2 < btc->tseg2_min)
91 *tseg2 = btc->tseg2_min;
92 if (*tseg2 > btc->tseg2_max)
93 *tseg2 = btc->tseg2_max;
94 *tseg1 = tseg - *tseg2;
95 if (*tseg1 > btc->tseg1_max) {
96 *tseg1 = btc->tseg1_max;
97 *tseg2 = tseg - *tseg1;
98 }
99 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
100}
101
102static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
103 const struct can_bittiming_const *btc)
104{
105 struct can_priv *priv = netdev_priv(dev);
106 long rate, best_rate = 0;
107 long best_error = 1000000000, error = 0;
108 int best_tseg = 0, best_brp = 0, brp = 0;
109 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
110 int spt_error = 1000, spt = 0, sampl_pt;
111 u64 v64;
112
113 /* Use CIA recommended sample points */
114 if (bt->sample_point) {
115 sampl_pt = bt->sample_point;
116 } else {
117 if (bt->bitrate > 800000)
118 sampl_pt = 750;
119 else if (bt->bitrate > 500000)
120 sampl_pt = 800;
121 else
122 sampl_pt = 875;
123 }
124
125 /* tseg even = round down, odd = round up */
126 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
127 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
128 tsegall = 1 + tseg / 2;
129 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
130 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
131 /* chose brp step which is possible in system */
132 brp = (brp / btc->brp_inc) * btc->brp_inc;
133 if ((brp < btc->brp_min) || (brp > btc->brp_max))
134 continue;
135 rate = priv->clock.freq / (brp * tsegall);
136 error = bt->bitrate - rate;
137 /* tseg brp biterror */
138 if (error < 0)
139 error = -error;
140 if (error > best_error)
141 continue;
142 best_error = error;
143 if (error == 0) {
144 spt = can_update_spt(btc, sampl_pt, tseg / 2,
145 &tseg1, &tseg2);
146 error = sampl_pt - spt;
147 if (error < 0)
148 error = -error;
149 if (error > spt_error)
150 continue;
151 spt_error = error;
152 }
153 best_tseg = tseg / 2;
154 best_brp = brp;
155 best_rate = rate;
156 if (error == 0)
157 break;
158 }
159
160 if (best_error) {
161 /* Error in one-tenth of a percent */
162 error = (best_error * 1000) / bt->bitrate;
163 if (error > CAN_CALC_MAX_ERROR) {
164 netdev_err(dev,
165 "bitrate error %ld.%ld%% too high\n",
166 error / 10, error % 10);
167 return -EDOM;
168 } else {
169 netdev_warn(dev, "bitrate error %ld.%ld%%\n",
170 error / 10, error % 10);
171 }
172 }
173
174 /* real sample point */
175 bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
176 &tseg1, &tseg2);
177
178 v64 = (u64)best_brp * 1000000000UL;
179 do_div(v64, priv->clock.freq);
180 bt->tq = (u32)v64;
181 bt->prop_seg = tseg1 / 2;
182 bt->phase_seg1 = tseg1 - bt->prop_seg;
183 bt->phase_seg2 = tseg2;
184
185 /* check for sjw user settings */
186 if (!bt->sjw || !btc->sjw_max)
187 bt->sjw = 1;
188 else {
189 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
190 if (bt->sjw > btc->sjw_max)
191 bt->sjw = btc->sjw_max;
192 /* bt->sjw must not be higher than tseg2 */
193 if (tseg2 < bt->sjw)
194 bt->sjw = tseg2;
195 }
196
197 bt->brp = best_brp;
198 /* real bit-rate */
199 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
200
201 return 0;
202}
203#else /* !CONFIG_CAN_CALC_BITTIMING */
204static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
205 const struct can_bittiming_const *btc)
206{
207 netdev_err(dev, "bit-timing calculation not available\n");
208 return -EINVAL;
209}
210#endif /* CONFIG_CAN_CALC_BITTIMING */
211
212/*
213 * Checks the validity of the specified bit-timing parameters prop_seg,
214 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
215 * prescaler value brp. You can find more information in the header
216 * file linux/can/netlink.h.
217 */
218static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
219 const struct can_bittiming_const *btc)
220{
221 struct can_priv *priv = netdev_priv(dev);
222 int tseg1, alltseg;
223 u64 brp64;
224
225 tseg1 = bt->prop_seg + bt->phase_seg1;
226 if (!bt->sjw)
227 bt->sjw = 1;
228 if (bt->sjw > btc->sjw_max ||
229 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
230 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
231 return -ERANGE;
232
233 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
234 if (btc->brp_inc > 1)
235 do_div(brp64, btc->brp_inc);
236 brp64 += 500000000UL - 1;
237 do_div(brp64, 1000000000UL); /* the practicable BRP */
238 if (btc->brp_inc > 1)
239 brp64 *= btc->brp_inc;
240 bt->brp = (u32)brp64;
241
242 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
243 return -EINVAL;
244
245 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
246 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
247 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
248
249 return 0;
250}
251
252static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
253 const struct can_bittiming_const *btc)
254{
255 int err;
256
257 /* Check if the CAN device has bit-timing parameters */
258 if (!btc)
259 return -EOPNOTSUPP;
260
261 /*
262 * Depending on the given can_bittiming parameter structure the CAN
263 * timing parameters are calculated based on the provided bitrate OR
264 * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
265 * provided directly which are then checked and fixed up.
266 */
267 if (!bt->tq && bt->bitrate)
268 err = can_calc_bittiming(dev, bt, btc);
269 else if (bt->tq && !bt->bitrate)
270 err = can_fixup_bittiming(dev, bt, btc);
271 else
272 err = -EINVAL;
273
274 return err;
275}
276
277/*
278 * Local echo of CAN messages
279 *
280 * CAN network devices *should* support a local echo functionality
281 * (see Documentation/networking/can.txt). To test the handling of CAN
282 * interfaces that do not support the local echo both driver types are
283 * implemented. In the case that the driver does not support the echo
284 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
285 * to perform the echo as a fallback solution.
286 */
287static void can_flush_echo_skb(struct net_device *dev)
288{
289 struct can_priv *priv = netdev_priv(dev);
290 struct net_device_stats *stats = &dev->stats;
291 int i;
292
293 for (i = 0; i < priv->echo_skb_max; i++) {
294 if (priv->echo_skb[i]) {
295 kfree_skb(priv->echo_skb[i]);
296 priv->echo_skb[i] = NULL;
297 stats->tx_dropped++;
298 stats->tx_aborted_errors++;
299 }
300 }
301}
302
303/*
304 * Put the skb on the stack to be looped backed locally lateron
305 *
306 * The function is typically called in the start_xmit function
307 * of the device driver. The driver must protect access to
308 * priv->echo_skb, if necessary.
309 */
310void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
311 unsigned int idx)
312{
313 struct can_priv *priv = netdev_priv(dev);
314
315 BUG_ON(idx >= priv->echo_skb_max);
316
317 /* check flag whether this packet has to be looped back */
318 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
319 (skb->protocol != htons(ETH_P_CAN) &&
320 skb->protocol != htons(ETH_P_CANFD))) {
321 kfree_skb(skb);
322 return;
323 }
324
325 if (!priv->echo_skb[idx]) {
326
327 skb = can_create_echo_skb(skb);
328 if (!skb)
329 return;
330
331 /* make settings for echo to reduce code in irq context */
332 skb->pkt_type = PACKET_BROADCAST;
333 skb->ip_summed = CHECKSUM_UNNECESSARY;
334 skb->dev = dev;
335
336 /* save this skb for tx interrupt echo handling */
337 priv->echo_skb[idx] = skb;
338 } else {
339 /* locking problem with netif_stop_queue() ?? */
340 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
341 kfree_skb(skb);
342 }
343}
344EXPORT_SYMBOL_GPL(can_put_echo_skb);
345
346/*
347 * Get the skb from the stack and loop it back locally
348 *
349 * The function is typically called when the TX done interrupt
350 * is handled in the device driver. The driver must protect
351 * access to priv->echo_skb, if necessary.
352 */
353unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
354{
355 struct can_priv *priv = netdev_priv(dev);
356
357 BUG_ON(idx >= priv->echo_skb_max);
358
359 if (priv->echo_skb[idx]) {
360 struct sk_buff *skb = priv->echo_skb[idx];
361 struct can_frame *cf = (struct can_frame *)skb->data;
362 u8 dlc = cf->can_dlc;
363
364 netif_rx(priv->echo_skb[idx]);
365 priv->echo_skb[idx] = NULL;
366
367 return dlc;
368 }
369
370 return 0;
371}
372EXPORT_SYMBOL_GPL(can_get_echo_skb);
373
374/*
375 * Remove the skb from the stack and free it.
376 *
377 * The function is typically called when TX failed.
378 */
379void can_free_echo_skb(struct net_device *dev, unsigned int idx)
380{
381 struct can_priv *priv = netdev_priv(dev);
382
383 BUG_ON(idx >= priv->echo_skb_max);
384
385 if (priv->echo_skb[idx]) {
386 kfree_skb(priv->echo_skb[idx]);
387 priv->echo_skb[idx] = NULL;
388 }
389}
390EXPORT_SYMBOL_GPL(can_free_echo_skb);
391
392/*
393 * CAN device restart for bus-off recovery
394 */
395static void can_restart(unsigned long data)
396{
397 struct net_device *dev = (struct net_device *)data;
398 struct can_priv *priv = netdev_priv(dev);
399 struct net_device_stats *stats = &dev->stats;
400 struct sk_buff *skb;
401 struct can_frame *cf;
402 int err;
403
404 BUG_ON(netif_carrier_ok(dev));
405
406 /*
407 * No synchronization needed because the device is bus-off and
408 * no messages can come in or go out.
409 */
410 can_flush_echo_skb(dev);
411
412 /* send restart message upstream */
413 skb = alloc_can_err_skb(dev, &cf);
414 if (skb == NULL) {
415 err = -ENOMEM;
416 goto restart;
417 }
418 cf->can_id |= CAN_ERR_RESTARTED;
419
420 netif_rx(skb);
421
422 stats->rx_packets++;
423 stats->rx_bytes += cf->can_dlc;
424
425restart:
426 netdev_dbg(dev, "restarted\n");
427 priv->can_stats.restarts++;
428
429 /* Now restart the device */
430 err = priv->do_set_mode(dev, CAN_MODE_START);
431
432 netif_carrier_on(dev);
433 if (err)
434 netdev_err(dev, "Error %d during restart", err);
435}
436
437int can_restart_now(struct net_device *dev)
438{
439 struct can_priv *priv = netdev_priv(dev);
440
441 /*
442 * A manual restart is only permitted if automatic restart is
443 * disabled and the device is in the bus-off state
444 */
445 if (priv->restart_ms)
446 return -EINVAL;
447 if (priv->state != CAN_STATE_BUS_OFF)
448 return -EBUSY;
449
450 /* Runs as soon as possible in the timer context */
451 mod_timer(&priv->restart_timer, jiffies);
452
453 return 0;
454}
455
456/*
457 * CAN bus-off
458 *
459 * This functions should be called when the device goes bus-off to
460 * tell the netif layer that no more packets can be sent or received.
461 * If enabled, a timer is started to trigger bus-off recovery.
462 */
463void can_bus_off(struct net_device *dev)
464{
465 struct can_priv *priv = netdev_priv(dev);
466
467 netdev_dbg(dev, "bus-off\n");
468
469 netif_carrier_off(dev);
470 priv->can_stats.bus_off++;
471
472 if (priv->restart_ms)
473 mod_timer(&priv->restart_timer,
474 jiffies + (priv->restart_ms * HZ) / 1000);
475}
476EXPORT_SYMBOL_GPL(can_bus_off);
477
478static void can_setup(struct net_device *dev)
479{
480 dev->type = ARPHRD_CAN;
481 dev->mtu = CAN_MTU;
482 dev->hard_header_len = 0;
483 dev->addr_len = 0;
484 dev->tx_queue_len = 10;
485
486 /* New-style flags. */
487 dev->flags = IFF_NOARP;
488 dev->features = NETIF_F_HW_CSUM;
489}
490
491struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
492{
493 struct sk_buff *skb;
494
495 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
496 sizeof(struct can_frame));
497 if (unlikely(!skb))
498 return NULL;
499
500 skb->protocol = htons(ETH_P_CAN);
501 skb->pkt_type = PACKET_BROADCAST;
502 skb->ip_summed = CHECKSUM_UNNECESSARY;
503
504 can_skb_reserve(skb);
505 can_skb_prv(skb)->ifindex = dev->ifindex;
506
507 *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
508 memset(*cf, 0, sizeof(struct can_frame));
509
510 return skb;
511}
512EXPORT_SYMBOL_GPL(alloc_can_skb);
513
514struct sk_buff *alloc_canfd_skb(struct net_device *dev,
515 struct canfd_frame **cfd)
516{
517 struct sk_buff *skb;
518
519 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
520 sizeof(struct canfd_frame));
521 if (unlikely(!skb))
522 return NULL;
523
524 skb->protocol = htons(ETH_P_CANFD);
525 skb->pkt_type = PACKET_BROADCAST;
526 skb->ip_summed = CHECKSUM_UNNECESSARY;
527
528 can_skb_reserve(skb);
529 can_skb_prv(skb)->ifindex = dev->ifindex;
530
531 *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
532 memset(*cfd, 0, sizeof(struct canfd_frame));
533
534 return skb;
535}
536EXPORT_SYMBOL_GPL(alloc_canfd_skb);
537
538struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
539{
540 struct sk_buff *skb;
541
542 skb = alloc_can_skb(dev, cf);
543 if (unlikely(!skb))
544 return NULL;
545
546 (*cf)->can_id = CAN_ERR_FLAG;
547 (*cf)->can_dlc = CAN_ERR_DLC;
548
549 return skb;
550}
551EXPORT_SYMBOL_GPL(alloc_can_err_skb);
552
553/*
554 * Allocate and setup space for the CAN network device
555 */
556struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
557{
558 struct net_device *dev;
559 struct can_priv *priv;
560 int size;
561
562 if (echo_skb_max)
563 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
564 echo_skb_max * sizeof(struct sk_buff *);
565 else
566 size = sizeof_priv;
567
568 dev = alloc_netdev(size, "can%d", can_setup);
569 if (!dev)
570 return NULL;
571
572 priv = netdev_priv(dev);
573
574 if (echo_skb_max) {
575 priv->echo_skb_max = echo_skb_max;
576 priv->echo_skb = (void *)priv +
577 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
578 }
579
580 priv->state = CAN_STATE_STOPPED;
581
582 init_timer(&priv->restart_timer);
583
584 return dev;
585}
586EXPORT_SYMBOL_GPL(alloc_candev);
587
588/*
589 * Free space of the CAN network device
590 */
591void free_candev(struct net_device *dev)
592{
593 free_netdev(dev);
594}
595EXPORT_SYMBOL_GPL(free_candev);
596
597/*
598 * changing MTU and control mode for CAN/CANFD devices
599 */
600int can_change_mtu(struct net_device *dev, int new_mtu)
601{
602 struct can_priv *priv = netdev_priv(dev);
603
604 /* Do not allow changing the MTU while running */
605 if (dev->flags & IFF_UP)
606 return -EBUSY;
607
608 /* allow change of MTU according to the CANFD ability of the device */
609 switch (new_mtu) {
610 case CAN_MTU:
611 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
612 break;
613
614 case CANFD_MTU:
615 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
616 return -EINVAL;
617
618 priv->ctrlmode |= CAN_CTRLMODE_FD;
619 break;
620
621 default:
622 return -EINVAL;
623 }
624
625 dev->mtu = new_mtu;
626 return 0;
627}
628EXPORT_SYMBOL_GPL(can_change_mtu);
629
630/*
631 * Common open function when the device gets opened.
632 *
633 * This function should be called in the open function of the device
634 * driver.
635 */
636int open_candev(struct net_device *dev)
637{
638 struct can_priv *priv = netdev_priv(dev);
639
640 if (!priv->bittiming.bitrate) {
641 netdev_err(dev, "bit-timing not yet defined\n");
642 return -EINVAL;
643 }
644
645 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
646 if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
647 (!priv->data_bittiming.bitrate ||
648 (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
649 netdev_err(dev, "incorrect/missing data bit-timing\n");
650 return -EINVAL;
651 }
652
653 /* Switch carrier on if device was stopped while in bus-off state */
654 if (!netif_carrier_ok(dev))
655 netif_carrier_on(dev);
656
657 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
658
659 return 0;
660}
661EXPORT_SYMBOL_GPL(open_candev);
662
663/*
664 * Common close function for cleanup before the device gets closed.
665 *
666 * This function should be called in the close function of the device
667 * driver.
668 */
669void close_candev(struct net_device *dev)
670{
671 struct can_priv *priv = netdev_priv(dev);
672
673 del_timer_sync(&priv->restart_timer);
674 can_flush_echo_skb(dev);
675}
676EXPORT_SYMBOL_GPL(close_candev);
677
678/*
679 * CAN netlink interface
680 */
681static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
682 [IFLA_CAN_STATE] = { .type = NLA_U32 },
683 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
684 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
685 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
686 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
687 [IFLA_CAN_BITTIMING_CONST]
688 = { .len = sizeof(struct can_bittiming_const) },
689 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
690 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
691 [IFLA_CAN_DATA_BITTIMING]
692 = { .len = sizeof(struct can_bittiming) },
693 [IFLA_CAN_DATA_BITTIMING_CONST]
694 = { .len = sizeof(struct can_bittiming_const) },
695};
696
697static int can_changelink(struct net_device *dev,
698 struct nlattr *tb[], struct nlattr *data[])
699{
700 struct can_priv *priv = netdev_priv(dev);
701 int err;
702
703 /* We need synchronization with dev->stop() */
704 ASSERT_RTNL();
705
706 if (data[IFLA_CAN_BITTIMING]) {
707 struct can_bittiming bt;
708
709 /* Do not allow changing bittiming while running */
710 if (dev->flags & IFF_UP)
711 return -EBUSY;
712 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
713 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
714 if (err)
715 return err;
716 memcpy(&priv->bittiming, &bt, sizeof(bt));
717
718 if (priv->do_set_bittiming) {
719 /* Finally, set the bit-timing registers */
720 err = priv->do_set_bittiming(dev);
721 if (err)
722 return err;
723 }
724 }
725
726 if (data[IFLA_CAN_CTRLMODE]) {
727 struct can_ctrlmode *cm;
728
729 /* Do not allow changing controller mode while running */
730 if (dev->flags & IFF_UP)
731 return -EBUSY;
732 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
733 if (cm->flags & ~priv->ctrlmode_supported)
734 return -EOPNOTSUPP;
735 priv->ctrlmode &= ~cm->mask;
736 priv->ctrlmode |= cm->flags;
737
738 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
739 if (priv->ctrlmode & CAN_CTRLMODE_FD)
740 dev->mtu = CANFD_MTU;
741 else
742 dev->mtu = CAN_MTU;
743 }
744
745 if (data[IFLA_CAN_RESTART_MS]) {
746 /* Do not allow changing restart delay while running */
747 if (dev->flags & IFF_UP)
748 return -EBUSY;
749 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
750 }
751
752 if (data[IFLA_CAN_RESTART]) {
753 /* Do not allow a restart while not running */
754 if (!(dev->flags & IFF_UP))
755 return -EINVAL;
756 err = can_restart_now(dev);
757 if (err)
758 return err;
759 }
760
761 if (data[IFLA_CAN_DATA_BITTIMING]) {
762 struct can_bittiming dbt;
763
764 /* Do not allow changing bittiming while running */
765 if (dev->flags & IFF_UP)
766 return -EBUSY;
767 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
768 sizeof(dbt));
769 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
770 if (err)
771 return err;
772 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
773
774 if (priv->do_set_data_bittiming) {
775 /* Finally, set the bit-timing registers */
776 err = priv->do_set_data_bittiming(dev);
777 if (err)
778 return err;
779 }
780 }
781
782 return 0;
783}
784
785static size_t can_get_size(const struct net_device *dev)
786{
787 struct can_priv *priv = netdev_priv(dev);
788 size_t size = 0;
789
790 if (priv->bittiming.bitrate) /* IFLA_CAN_BITTIMING */
791 size += nla_total_size(sizeof(struct can_bittiming));
792 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
793 size += nla_total_size(sizeof(struct can_bittiming_const));
794 size += nla_total_size(sizeof(struct can_clock)); /* IFLA_CAN_CLOCK */
795 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
796 size += nla_total_size(sizeof(struct can_ctrlmode)); /* IFLA_CAN_CTRLMODE */
797 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
798 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
799 size += nla_total_size(sizeof(struct can_berr_counter));
800 if (priv->data_bittiming.bitrate) /* IFLA_CAN_DATA_BITTIMING */
801 size += nla_total_size(sizeof(struct can_bittiming));
802 if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */
803 size += nla_total_size(sizeof(struct can_bittiming_const));
804
805 return size;
806}
807
808static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
809{
810 struct can_priv *priv = netdev_priv(dev);
811 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
812 struct can_berr_counter bec;
813 enum can_state state = priv->state;
814
815 if (priv->do_get_state)
816 priv->do_get_state(dev, &state);
817
818 if ((priv->bittiming.bitrate &&
819 nla_put(skb, IFLA_CAN_BITTIMING,
820 sizeof(priv->bittiming), &priv->bittiming)) ||
821
822 (priv->bittiming_const &&
823 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
824 sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
825
826 nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
827 nla_put_u32(skb, IFLA_CAN_STATE, state) ||
828 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
829 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
830
831 (priv->do_get_berr_counter &&
832 !priv->do_get_berr_counter(dev, &bec) &&
833 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
834
835 (priv->data_bittiming.bitrate &&
836 nla_put(skb, IFLA_CAN_DATA_BITTIMING,
837 sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
838
839 (priv->data_bittiming_const &&
840 nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
841 sizeof(*priv->data_bittiming_const),
842 priv->data_bittiming_const)))
843 return -EMSGSIZE;
844
845 return 0;
846}
847
848static size_t can_get_xstats_size(const struct net_device *dev)
849{
850 return sizeof(struct can_device_stats);
851}
852
853static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
854{
855 struct can_priv *priv = netdev_priv(dev);
856
857 if (nla_put(skb, IFLA_INFO_XSTATS,
858 sizeof(priv->can_stats), &priv->can_stats))
859 goto nla_put_failure;
860 return 0;
861
862nla_put_failure:
863 return -EMSGSIZE;
864}
865
866static int can_newlink(struct net *src_net, struct net_device *dev,
867 struct nlattr *tb[], struct nlattr *data[])
868{
869 return -EOPNOTSUPP;
870}
871
872static struct rtnl_link_ops can_link_ops __read_mostly = {
873 .kind = "can",
874 .maxtype = IFLA_CAN_MAX,
875 .policy = can_policy,
876 .setup = can_setup,
877 .newlink = can_newlink,
878 .changelink = can_changelink,
879 .get_size = can_get_size,
880 .fill_info = can_fill_info,
881 .get_xstats_size = can_get_xstats_size,
882 .fill_xstats = can_fill_xstats,
883};
884
885/*
886 * Register the CAN network device
887 */
888int register_candev(struct net_device *dev)
889{
890 dev->rtnl_link_ops = &can_link_ops;
891 return register_netdev(dev);
892}
893EXPORT_SYMBOL_GPL(register_candev);
894
895/*
896 * Unregister the CAN network device
897 */
898void unregister_candev(struct net_device *dev)
899{
900 unregister_netdev(dev);
901}
902EXPORT_SYMBOL_GPL(unregister_candev);
903
904/*
905 * Test if a network device is a candev based device
906 * and return the can_priv* if so.
907 */
908struct can_priv *safe_candev_priv(struct net_device *dev)
909{
910 if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
911 return NULL;
912
913 return netdev_priv(dev);
914}
915EXPORT_SYMBOL_GPL(safe_candev_priv);
916
917static __init int can_dev_init(void)
918{
919 int err;
920
921 can_led_notifier_init();
922
923 err = rtnl_link_register(&can_link_ops);
924 if (!err)
925 printk(KERN_INFO MOD_DESC "\n");
926
927 return err;
928}
929module_init(can_dev_init);
930
931static __exit void can_dev_exit(void)
932{
933 rtnl_link_unregister(&can_link_ops);
934
935 can_led_notifier_exit();
936}
937module_exit(can_dev_exit);
938
939MODULE_ALIAS_RTNL_LINK("can");
1/*
2 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
3 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
4 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the version 2 of the GNU General Public License
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/module.h>
21#include <linux/kernel.h>
22#include <linux/slab.h>
23#include <linux/netdevice.h>
24#include <linux/if_arp.h>
25#include <linux/can.h>
26#include <linux/can/dev.h>
27#include <linux/can/netlink.h>
28#include <net/rtnetlink.h>
29
30#define MOD_DESC "CAN device driver interface"
31
32MODULE_DESCRIPTION(MOD_DESC);
33MODULE_LICENSE("GPL v2");
34MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
35
36#ifdef CONFIG_CAN_CALC_BITTIMING
37#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
38
39/*
40 * Bit-timing calculation derived from:
41 *
42 * Code based on LinCAN sources and H8S2638 project
43 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
44 * Copyright 2005 Stanislav Marek
45 * email: pisa@cmp.felk.cvut.cz
46 *
47 * Calculates proper bit-timing parameters for a specified bit-rate
48 * and sample-point, which can then be used to set the bit-timing
49 * registers of the CAN controller. You can find more information
50 * in the header file linux/can/netlink.h.
51 */
52static int can_update_spt(const struct can_bittiming_const *btc,
53 int sampl_pt, int tseg, int *tseg1, int *tseg2)
54{
55 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
56 if (*tseg2 < btc->tseg2_min)
57 *tseg2 = btc->tseg2_min;
58 if (*tseg2 > btc->tseg2_max)
59 *tseg2 = btc->tseg2_max;
60 *tseg1 = tseg - *tseg2;
61 if (*tseg1 > btc->tseg1_max) {
62 *tseg1 = btc->tseg1_max;
63 *tseg2 = tseg - *tseg1;
64 }
65 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
66}
67
68static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
69{
70 struct can_priv *priv = netdev_priv(dev);
71 const struct can_bittiming_const *btc = priv->bittiming_const;
72 long rate, best_rate = 0;
73 long best_error = 1000000000, error = 0;
74 int best_tseg = 0, best_brp = 0, brp = 0;
75 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
76 int spt_error = 1000, spt = 0, sampl_pt;
77 u64 v64;
78
79 if (!priv->bittiming_const)
80 return -ENOTSUPP;
81
82 /* Use CIA recommended sample points */
83 if (bt->sample_point) {
84 sampl_pt = bt->sample_point;
85 } else {
86 if (bt->bitrate > 800000)
87 sampl_pt = 750;
88 else if (bt->bitrate > 500000)
89 sampl_pt = 800;
90 else
91 sampl_pt = 875;
92 }
93
94 /* tseg even = round down, odd = round up */
95 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
96 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
97 tsegall = 1 + tseg / 2;
98 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
99 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
100 /* chose brp step which is possible in system */
101 brp = (brp / btc->brp_inc) * btc->brp_inc;
102 if ((brp < btc->brp_min) || (brp > btc->brp_max))
103 continue;
104 rate = priv->clock.freq / (brp * tsegall);
105 error = bt->bitrate - rate;
106 /* tseg brp biterror */
107 if (error < 0)
108 error = -error;
109 if (error > best_error)
110 continue;
111 best_error = error;
112 if (error == 0) {
113 spt = can_update_spt(btc, sampl_pt, tseg / 2,
114 &tseg1, &tseg2);
115 error = sampl_pt - spt;
116 if (error < 0)
117 error = -error;
118 if (error > spt_error)
119 continue;
120 spt_error = error;
121 }
122 best_tseg = tseg / 2;
123 best_brp = brp;
124 best_rate = rate;
125 if (error == 0)
126 break;
127 }
128
129 if (best_error) {
130 /* Error in one-tenth of a percent */
131 error = (best_error * 1000) / bt->bitrate;
132 if (error > CAN_CALC_MAX_ERROR) {
133 netdev_err(dev,
134 "bitrate error %ld.%ld%% too high\n",
135 error / 10, error % 10);
136 return -EDOM;
137 } else {
138 netdev_warn(dev, "bitrate error %ld.%ld%%\n",
139 error / 10, error % 10);
140 }
141 }
142
143 /* real sample point */
144 bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
145 &tseg1, &tseg2);
146
147 v64 = (u64)best_brp * 1000000000UL;
148 do_div(v64, priv->clock.freq);
149 bt->tq = (u32)v64;
150 bt->prop_seg = tseg1 / 2;
151 bt->phase_seg1 = tseg1 - bt->prop_seg;
152 bt->phase_seg2 = tseg2;
153
154 /* check for sjw user settings */
155 if (!bt->sjw || !btc->sjw_max)
156 bt->sjw = 1;
157 else {
158 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
159 if (bt->sjw > btc->sjw_max)
160 bt->sjw = btc->sjw_max;
161 /* bt->sjw must not be higher than tseg2 */
162 if (tseg2 < bt->sjw)
163 bt->sjw = tseg2;
164 }
165
166 bt->brp = best_brp;
167 /* real bit-rate */
168 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
169
170 return 0;
171}
172#else /* !CONFIG_CAN_CALC_BITTIMING */
173static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
174{
175 netdev_err(dev, "bit-timing calculation not available\n");
176 return -EINVAL;
177}
178#endif /* CONFIG_CAN_CALC_BITTIMING */
179
180/*
181 * Checks the validity of the specified bit-timing parameters prop_seg,
182 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
183 * prescaler value brp. You can find more information in the header
184 * file linux/can/netlink.h.
185 */
186static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
187{
188 struct can_priv *priv = netdev_priv(dev);
189 const struct can_bittiming_const *btc = priv->bittiming_const;
190 int tseg1, alltseg;
191 u64 brp64;
192
193 if (!priv->bittiming_const)
194 return -ENOTSUPP;
195
196 tseg1 = bt->prop_seg + bt->phase_seg1;
197 if (!bt->sjw)
198 bt->sjw = 1;
199 if (bt->sjw > btc->sjw_max ||
200 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
201 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
202 return -ERANGE;
203
204 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
205 if (btc->brp_inc > 1)
206 do_div(brp64, btc->brp_inc);
207 brp64 += 500000000UL - 1;
208 do_div(brp64, 1000000000UL); /* the practicable BRP */
209 if (btc->brp_inc > 1)
210 brp64 *= btc->brp_inc;
211 bt->brp = (u32)brp64;
212
213 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
214 return -EINVAL;
215
216 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
217 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
218 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
219
220 return 0;
221}
222
223static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
224{
225 struct can_priv *priv = netdev_priv(dev);
226 int err;
227
228 /* Check if the CAN device has bit-timing parameters */
229 if (priv->bittiming_const) {
230
231 /* Non-expert mode? Check if the bitrate has been pre-defined */
232 if (!bt->tq)
233 /* Determine bit-timing parameters */
234 err = can_calc_bittiming(dev, bt);
235 else
236 /* Check bit-timing params and calculate proper brp */
237 err = can_fixup_bittiming(dev, bt);
238 if (err)
239 return err;
240 }
241
242 return 0;
243}
244
245/*
246 * Local echo of CAN messages
247 *
248 * CAN network devices *should* support a local echo functionality
249 * (see Documentation/networking/can.txt). To test the handling of CAN
250 * interfaces that do not support the local echo both driver types are
251 * implemented. In the case that the driver does not support the echo
252 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
253 * to perform the echo as a fallback solution.
254 */
255static void can_flush_echo_skb(struct net_device *dev)
256{
257 struct can_priv *priv = netdev_priv(dev);
258 struct net_device_stats *stats = &dev->stats;
259 int i;
260
261 for (i = 0; i < priv->echo_skb_max; i++) {
262 if (priv->echo_skb[i]) {
263 kfree_skb(priv->echo_skb[i]);
264 priv->echo_skb[i] = NULL;
265 stats->tx_dropped++;
266 stats->tx_aborted_errors++;
267 }
268 }
269}
270
271/*
272 * Put the skb on the stack to be looped backed locally lateron
273 *
274 * The function is typically called in the start_xmit function
275 * of the device driver. The driver must protect access to
276 * priv->echo_skb, if necessary.
277 */
278void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
279 unsigned int idx)
280{
281 struct can_priv *priv = netdev_priv(dev);
282
283 BUG_ON(idx >= priv->echo_skb_max);
284
285 /* check flag whether this packet has to be looped back */
286 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
287 kfree_skb(skb);
288 return;
289 }
290
291 if (!priv->echo_skb[idx]) {
292 struct sock *srcsk = skb->sk;
293
294 if (atomic_read(&skb->users) != 1) {
295 struct sk_buff *old_skb = skb;
296
297 skb = skb_clone(old_skb, GFP_ATOMIC);
298 kfree_skb(old_skb);
299 if (!skb)
300 return;
301 } else
302 skb_orphan(skb);
303
304 skb->sk = srcsk;
305
306 /* make settings for echo to reduce code in irq context */
307 skb->protocol = htons(ETH_P_CAN);
308 skb->pkt_type = PACKET_BROADCAST;
309 skb->ip_summed = CHECKSUM_UNNECESSARY;
310 skb->dev = dev;
311
312 /* save this skb for tx interrupt echo handling */
313 priv->echo_skb[idx] = skb;
314 } else {
315 /* locking problem with netif_stop_queue() ?? */
316 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
317 kfree_skb(skb);
318 }
319}
320EXPORT_SYMBOL_GPL(can_put_echo_skb);
321
322/*
323 * Get the skb from the stack and loop it back locally
324 *
325 * The function is typically called when the TX done interrupt
326 * is handled in the device driver. The driver must protect
327 * access to priv->echo_skb, if necessary.
328 */
329unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
330{
331 struct can_priv *priv = netdev_priv(dev);
332
333 BUG_ON(idx >= priv->echo_skb_max);
334
335 if (priv->echo_skb[idx]) {
336 struct sk_buff *skb = priv->echo_skb[idx];
337 struct can_frame *cf = (struct can_frame *)skb->data;
338 u8 dlc = cf->can_dlc;
339
340 netif_rx(priv->echo_skb[idx]);
341 priv->echo_skb[idx] = NULL;
342
343 return dlc;
344 }
345
346 return 0;
347}
348EXPORT_SYMBOL_GPL(can_get_echo_skb);
349
350/*
351 * Remove the skb from the stack and free it.
352 *
353 * The function is typically called when TX failed.
354 */
355void can_free_echo_skb(struct net_device *dev, unsigned int idx)
356{
357 struct can_priv *priv = netdev_priv(dev);
358
359 BUG_ON(idx >= priv->echo_skb_max);
360
361 if (priv->echo_skb[idx]) {
362 kfree_skb(priv->echo_skb[idx]);
363 priv->echo_skb[idx] = NULL;
364 }
365}
366EXPORT_SYMBOL_GPL(can_free_echo_skb);
367
368/*
369 * CAN device restart for bus-off recovery
370 */
371void can_restart(unsigned long data)
372{
373 struct net_device *dev = (struct net_device *)data;
374 struct can_priv *priv = netdev_priv(dev);
375 struct net_device_stats *stats = &dev->stats;
376 struct sk_buff *skb;
377 struct can_frame *cf;
378 int err;
379
380 BUG_ON(netif_carrier_ok(dev));
381
382 /*
383 * No synchronization needed because the device is bus-off and
384 * no messages can come in or go out.
385 */
386 can_flush_echo_skb(dev);
387
388 /* send restart message upstream */
389 skb = alloc_can_err_skb(dev, &cf);
390 if (skb == NULL) {
391 err = -ENOMEM;
392 goto restart;
393 }
394 cf->can_id |= CAN_ERR_RESTARTED;
395
396 netif_rx(skb);
397
398 stats->rx_packets++;
399 stats->rx_bytes += cf->can_dlc;
400
401restart:
402 netdev_dbg(dev, "restarted\n");
403 priv->can_stats.restarts++;
404
405 /* Now restart the device */
406 err = priv->do_set_mode(dev, CAN_MODE_START);
407
408 netif_carrier_on(dev);
409 if (err)
410 netdev_err(dev, "Error %d during restart", err);
411}
412
413int can_restart_now(struct net_device *dev)
414{
415 struct can_priv *priv = netdev_priv(dev);
416
417 /*
418 * A manual restart is only permitted if automatic restart is
419 * disabled and the device is in the bus-off state
420 */
421 if (priv->restart_ms)
422 return -EINVAL;
423 if (priv->state != CAN_STATE_BUS_OFF)
424 return -EBUSY;
425
426 /* Runs as soon as possible in the timer context */
427 mod_timer(&priv->restart_timer, jiffies);
428
429 return 0;
430}
431
432/*
433 * CAN bus-off
434 *
435 * This functions should be called when the device goes bus-off to
436 * tell the netif layer that no more packets can be sent or received.
437 * If enabled, a timer is started to trigger bus-off recovery.
438 */
439void can_bus_off(struct net_device *dev)
440{
441 struct can_priv *priv = netdev_priv(dev);
442
443 netdev_dbg(dev, "bus-off\n");
444
445 netif_carrier_off(dev);
446 priv->can_stats.bus_off++;
447
448 if (priv->restart_ms)
449 mod_timer(&priv->restart_timer,
450 jiffies + (priv->restart_ms * HZ) / 1000);
451}
452EXPORT_SYMBOL_GPL(can_bus_off);
453
454static void can_setup(struct net_device *dev)
455{
456 dev->type = ARPHRD_CAN;
457 dev->mtu = sizeof(struct can_frame);
458 dev->hard_header_len = 0;
459 dev->addr_len = 0;
460 dev->tx_queue_len = 10;
461
462 /* New-style flags. */
463 dev->flags = IFF_NOARP;
464 dev->features = NETIF_F_HW_CSUM;
465}
466
467struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
468{
469 struct sk_buff *skb;
470
471 skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
472 if (unlikely(!skb))
473 return NULL;
474
475 skb->protocol = htons(ETH_P_CAN);
476 skb->pkt_type = PACKET_BROADCAST;
477 skb->ip_summed = CHECKSUM_UNNECESSARY;
478 *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
479 memset(*cf, 0, sizeof(struct can_frame));
480
481 return skb;
482}
483EXPORT_SYMBOL_GPL(alloc_can_skb);
484
485struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
486{
487 struct sk_buff *skb;
488
489 skb = alloc_can_skb(dev, cf);
490 if (unlikely(!skb))
491 return NULL;
492
493 (*cf)->can_id = CAN_ERR_FLAG;
494 (*cf)->can_dlc = CAN_ERR_DLC;
495
496 return skb;
497}
498EXPORT_SYMBOL_GPL(alloc_can_err_skb);
499
500/*
501 * Allocate and setup space for the CAN network device
502 */
503struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
504{
505 struct net_device *dev;
506 struct can_priv *priv;
507 int size;
508
509 if (echo_skb_max)
510 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
511 echo_skb_max * sizeof(struct sk_buff *);
512 else
513 size = sizeof_priv;
514
515 dev = alloc_netdev(size, "can%d", can_setup);
516 if (!dev)
517 return NULL;
518
519 priv = netdev_priv(dev);
520
521 if (echo_skb_max) {
522 priv->echo_skb_max = echo_skb_max;
523 priv->echo_skb = (void *)priv +
524 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
525 }
526
527 priv->state = CAN_STATE_STOPPED;
528
529 init_timer(&priv->restart_timer);
530
531 return dev;
532}
533EXPORT_SYMBOL_GPL(alloc_candev);
534
535/*
536 * Free space of the CAN network device
537 */
538void free_candev(struct net_device *dev)
539{
540 free_netdev(dev);
541}
542EXPORT_SYMBOL_GPL(free_candev);
543
544/*
545 * Common open function when the device gets opened.
546 *
547 * This function should be called in the open function of the device
548 * driver.
549 */
550int open_candev(struct net_device *dev)
551{
552 struct can_priv *priv = netdev_priv(dev);
553
554 if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
555 netdev_err(dev, "bit-timing not yet defined\n");
556 return -EINVAL;
557 }
558
559 /* Switch carrier on if device was stopped while in bus-off state */
560 if (!netif_carrier_ok(dev))
561 netif_carrier_on(dev);
562
563 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
564
565 return 0;
566}
567EXPORT_SYMBOL_GPL(open_candev);
568
569/*
570 * Common close function for cleanup before the device gets closed.
571 *
572 * This function should be called in the close function of the device
573 * driver.
574 */
575void close_candev(struct net_device *dev)
576{
577 struct can_priv *priv = netdev_priv(dev);
578
579 if (del_timer_sync(&priv->restart_timer))
580 dev_put(dev);
581 can_flush_echo_skb(dev);
582}
583EXPORT_SYMBOL_GPL(close_candev);
584
585/*
586 * CAN netlink interface
587 */
588static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
589 [IFLA_CAN_STATE] = { .type = NLA_U32 },
590 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
591 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
592 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
593 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
594 [IFLA_CAN_BITTIMING_CONST]
595 = { .len = sizeof(struct can_bittiming_const) },
596 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
597 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
598};
599
600static int can_changelink(struct net_device *dev,
601 struct nlattr *tb[], struct nlattr *data[])
602{
603 struct can_priv *priv = netdev_priv(dev);
604 int err;
605
606 /* We need synchronization with dev->stop() */
607 ASSERT_RTNL();
608
609 if (data[IFLA_CAN_CTRLMODE]) {
610 struct can_ctrlmode *cm;
611
612 /* Do not allow changing controller mode while running */
613 if (dev->flags & IFF_UP)
614 return -EBUSY;
615 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
616 if (cm->flags & ~priv->ctrlmode_supported)
617 return -EOPNOTSUPP;
618 priv->ctrlmode &= ~cm->mask;
619 priv->ctrlmode |= cm->flags;
620 }
621
622 if (data[IFLA_CAN_BITTIMING]) {
623 struct can_bittiming bt;
624
625 /* Do not allow changing bittiming while running */
626 if (dev->flags & IFF_UP)
627 return -EBUSY;
628 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
629 if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
630 return -EINVAL;
631 err = can_get_bittiming(dev, &bt);
632 if (err)
633 return err;
634 memcpy(&priv->bittiming, &bt, sizeof(bt));
635
636 if (priv->do_set_bittiming) {
637 /* Finally, set the bit-timing registers */
638 err = priv->do_set_bittiming(dev);
639 if (err)
640 return err;
641 }
642 }
643
644 if (data[IFLA_CAN_RESTART_MS]) {
645 /* Do not allow changing restart delay while running */
646 if (dev->flags & IFF_UP)
647 return -EBUSY;
648 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
649 }
650
651 if (data[IFLA_CAN_RESTART]) {
652 /* Do not allow a restart while not running */
653 if (!(dev->flags & IFF_UP))
654 return -EINVAL;
655 err = can_restart_now(dev);
656 if (err)
657 return err;
658 }
659
660 return 0;
661}
662
663static size_t can_get_size(const struct net_device *dev)
664{
665 struct can_priv *priv = netdev_priv(dev);
666 size_t size;
667
668 size = nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
669 size += sizeof(struct can_ctrlmode); /* IFLA_CAN_CTRLMODE */
670 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
671 size += sizeof(struct can_bittiming); /* IFLA_CAN_BITTIMING */
672 size += sizeof(struct can_clock); /* IFLA_CAN_CLOCK */
673 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
674 size += sizeof(struct can_berr_counter);
675 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
676 size += sizeof(struct can_bittiming_const);
677
678 return size;
679}
680
681static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
682{
683 struct can_priv *priv = netdev_priv(dev);
684 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
685 struct can_berr_counter bec;
686 enum can_state state = priv->state;
687
688 if (priv->do_get_state)
689 priv->do_get_state(dev, &state);
690 if (nla_put_u32(skb, IFLA_CAN_STATE, state) ||
691 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
692 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
693 nla_put(skb, IFLA_CAN_BITTIMING,
694 sizeof(priv->bittiming), &priv->bittiming) ||
695 nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
696 (priv->do_get_berr_counter &&
697 !priv->do_get_berr_counter(dev, &bec) &&
698 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
699 (priv->bittiming_const &&
700 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
701 sizeof(*priv->bittiming_const), priv->bittiming_const)))
702 goto nla_put_failure;
703 return 0;
704
705nla_put_failure:
706 return -EMSGSIZE;
707}
708
709static size_t can_get_xstats_size(const struct net_device *dev)
710{
711 return sizeof(struct can_device_stats);
712}
713
714static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
715{
716 struct can_priv *priv = netdev_priv(dev);
717
718 if (nla_put(skb, IFLA_INFO_XSTATS,
719 sizeof(priv->can_stats), &priv->can_stats))
720 goto nla_put_failure;
721 return 0;
722
723nla_put_failure:
724 return -EMSGSIZE;
725}
726
727static int can_newlink(struct net *src_net, struct net_device *dev,
728 struct nlattr *tb[], struct nlattr *data[])
729{
730 return -EOPNOTSUPP;
731}
732
733static struct rtnl_link_ops can_link_ops __read_mostly = {
734 .kind = "can",
735 .maxtype = IFLA_CAN_MAX,
736 .policy = can_policy,
737 .setup = can_setup,
738 .newlink = can_newlink,
739 .changelink = can_changelink,
740 .get_size = can_get_size,
741 .fill_info = can_fill_info,
742 .get_xstats_size = can_get_xstats_size,
743 .fill_xstats = can_fill_xstats,
744};
745
746/*
747 * Register the CAN network device
748 */
749int register_candev(struct net_device *dev)
750{
751 dev->rtnl_link_ops = &can_link_ops;
752 return register_netdev(dev);
753}
754EXPORT_SYMBOL_GPL(register_candev);
755
756/*
757 * Unregister the CAN network device
758 */
759void unregister_candev(struct net_device *dev)
760{
761 unregister_netdev(dev);
762}
763EXPORT_SYMBOL_GPL(unregister_candev);
764
765static __init int can_dev_init(void)
766{
767 int err;
768
769 err = rtnl_link_register(&can_link_ops);
770 if (!err)
771 printk(KERN_INFO MOD_DESC "\n");
772
773 return err;
774}
775module_init(can_dev_init);
776
777static __exit void can_dev_exit(void)
778{
779 rtnl_link_unregister(&can_link_ops);
780}
781module_exit(can_dev_exit);
782
783MODULE_ALIAS_RTNL_LINK("can");