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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/workqueue.h>
25#include <linux/can.h>
26#include <linux/can/dev.h>
27#include <linux/can/skb.h>
28#include <linux/can/netlink.h>
29#include <linux/can/led.h>
30#include <net/rtnetlink.h>
31
32#define MOD_DESC "CAN device driver interface"
33
34MODULE_DESCRIPTION(MOD_DESC);
35MODULE_LICENSE("GPL v2");
36MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
37
38/* CAN DLC to real data length conversion helpers */
39
40static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
41 8, 12, 16, 20, 24, 32, 48, 64};
42
43/* get data length from can_dlc with sanitized can_dlc */
44u8 can_dlc2len(u8 can_dlc)
45{
46 return dlc2len[can_dlc & 0x0F];
47}
48EXPORT_SYMBOL_GPL(can_dlc2len);
49
50static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, /* 0 - 8 */
51 9, 9, 9, 9, /* 9 - 12 */
52 10, 10, 10, 10, /* 13 - 16 */
53 11, 11, 11, 11, /* 17 - 20 */
54 12, 12, 12, 12, /* 21 - 24 */
55 13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
56 14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
57 14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
58 15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
59 15, 15, 15, 15, 15, 15, 15, 15}; /* 57 - 64 */
60
61/* map the sanitized data length to an appropriate data length code */
62u8 can_len2dlc(u8 len)
63{
64 if (unlikely(len > 64))
65 return 0xF;
66
67 return len2dlc[len];
68}
69EXPORT_SYMBOL_GPL(can_len2dlc);
70
71#ifdef CONFIG_CAN_CALC_BITTIMING
72#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
73#define CAN_CALC_SYNC_SEG 1
74
75/*
76 * Bit-timing calculation derived from:
77 *
78 * Code based on LinCAN sources and H8S2638 project
79 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
80 * Copyright 2005 Stanislav Marek
81 * email: pisa@cmp.felk.cvut.cz
82 *
83 * Calculates proper bit-timing parameters for a specified bit-rate
84 * and sample-point, which can then be used to set the bit-timing
85 * registers of the CAN controller. You can find more information
86 * in the header file linux/can/netlink.h.
87 */
88static int can_update_sample_point(const struct can_bittiming_const *btc,
89 unsigned int sample_point_nominal, unsigned int tseg,
90 unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
91 unsigned int *sample_point_error_ptr)
92{
93 unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
94 unsigned int sample_point, best_sample_point = 0;
95 unsigned int tseg1, tseg2;
96 int i;
97
98 for (i = 0; i <= 1; i++) {
99 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
100 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
101 tseg1 = tseg - tseg2;
102 if (tseg1 > btc->tseg1_max) {
103 tseg1 = btc->tseg1_max;
104 tseg2 = tseg - tseg1;
105 }
106
107 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
108 sample_point_error = abs(sample_point_nominal - sample_point);
109
110 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
111 best_sample_point = sample_point;
112 best_sample_point_error = sample_point_error;
113 *tseg1_ptr = tseg1;
114 *tseg2_ptr = tseg2;
115 }
116 }
117
118 if (sample_point_error_ptr)
119 *sample_point_error_ptr = best_sample_point_error;
120
121 return best_sample_point;
122}
123
124static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
125 const struct can_bittiming_const *btc)
126{
127 struct can_priv *priv = netdev_priv(dev);
128 unsigned int bitrate; /* current bitrate */
129 unsigned int bitrate_error; /* difference between current and nominal value */
130 unsigned int best_bitrate_error = UINT_MAX;
131 unsigned int sample_point_error; /* difference between current and nominal value */
132 unsigned int best_sample_point_error = UINT_MAX;
133 unsigned int sample_point_nominal; /* nominal sample point */
134 unsigned int best_tseg = 0; /* current best value for tseg */
135 unsigned int best_brp = 0; /* current best value for brp */
136 unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
137 u64 v64;
138
139 /* Use CiA recommended sample points */
140 if (bt->sample_point) {
141 sample_point_nominal = bt->sample_point;
142 } else {
143 if (bt->bitrate > 800000)
144 sample_point_nominal = 750;
145 else if (bt->bitrate > 500000)
146 sample_point_nominal = 800;
147 else
148 sample_point_nominal = 875;
149 }
150
151 /* tseg even = round down, odd = round up */
152 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
153 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
154 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
155
156 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
157 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
158
159 /* choose brp step which is possible in system */
160 brp = (brp / btc->brp_inc) * btc->brp_inc;
161 if ((brp < btc->brp_min) || (brp > btc->brp_max))
162 continue;
163
164 bitrate = priv->clock.freq / (brp * tsegall);
165 bitrate_error = abs(bt->bitrate - bitrate);
166
167 /* tseg brp biterror */
168 if (bitrate_error > best_bitrate_error)
169 continue;
170
171 /* reset sample point error if we have a better bitrate */
172 if (bitrate_error < best_bitrate_error)
173 best_sample_point_error = UINT_MAX;
174
175 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
176 if (sample_point_error > best_sample_point_error)
177 continue;
178
179 best_sample_point_error = sample_point_error;
180 best_bitrate_error = bitrate_error;
181 best_tseg = tseg / 2;
182 best_brp = brp;
183
184 if (bitrate_error == 0 && sample_point_error == 0)
185 break;
186 }
187
188 if (best_bitrate_error) {
189 /* Error in one-tenth of a percent */
190 v64 = (u64)best_bitrate_error * 1000;
191 do_div(v64, bt->bitrate);
192 bitrate_error = (u32)v64;
193 if (bitrate_error > CAN_CALC_MAX_ERROR) {
194 netdev_err(dev,
195 "bitrate error %d.%d%% too high\n",
196 bitrate_error / 10, bitrate_error % 10);
197 return -EDOM;
198 }
199 netdev_warn(dev, "bitrate error %d.%d%%\n",
200 bitrate_error / 10, bitrate_error % 10);
201 }
202
203 /* real sample point */
204 bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
205 &tseg1, &tseg2, NULL);
206
207 v64 = (u64)best_brp * 1000 * 1000 * 1000;
208 do_div(v64, priv->clock.freq);
209 bt->tq = (u32)v64;
210 bt->prop_seg = tseg1 / 2;
211 bt->phase_seg1 = tseg1 - bt->prop_seg;
212 bt->phase_seg2 = tseg2;
213
214 /* check for sjw user settings */
215 if (!bt->sjw || !btc->sjw_max) {
216 bt->sjw = 1;
217 } else {
218 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
219 if (bt->sjw > btc->sjw_max)
220 bt->sjw = btc->sjw_max;
221 /* bt->sjw must not be higher than tseg2 */
222 if (tseg2 < bt->sjw)
223 bt->sjw = tseg2;
224 }
225
226 bt->brp = best_brp;
227
228 /* real bitrate */
229 bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
230
231 return 0;
232}
233#else /* !CONFIG_CAN_CALC_BITTIMING */
234static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
235 const struct can_bittiming_const *btc)
236{
237 netdev_err(dev, "bit-timing calculation not available\n");
238 return -EINVAL;
239}
240#endif /* CONFIG_CAN_CALC_BITTIMING */
241
242/*
243 * Checks the validity of the specified bit-timing parameters prop_seg,
244 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
245 * prescaler value brp. You can find more information in the header
246 * file linux/can/netlink.h.
247 */
248static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
249 const struct can_bittiming_const *btc)
250{
251 struct can_priv *priv = netdev_priv(dev);
252 int tseg1, alltseg;
253 u64 brp64;
254
255 tseg1 = bt->prop_seg + bt->phase_seg1;
256 if (!bt->sjw)
257 bt->sjw = 1;
258 if (bt->sjw > btc->sjw_max ||
259 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
260 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
261 return -ERANGE;
262
263 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
264 if (btc->brp_inc > 1)
265 do_div(brp64, btc->brp_inc);
266 brp64 += 500000000UL - 1;
267 do_div(brp64, 1000000000UL); /* the practicable BRP */
268 if (btc->brp_inc > 1)
269 brp64 *= btc->brp_inc;
270 bt->brp = (u32)brp64;
271
272 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
273 return -EINVAL;
274
275 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
276 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
277 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
278
279 return 0;
280}
281
282static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
283 const struct can_bittiming_const *btc)
284{
285 int err;
286
287 /* Check if the CAN device has bit-timing parameters */
288 if (!btc)
289 return -EOPNOTSUPP;
290
291 /*
292 * Depending on the given can_bittiming parameter structure the CAN
293 * timing parameters are calculated based on the provided bitrate OR
294 * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
295 * provided directly which are then checked and fixed up.
296 */
297 if (!bt->tq && bt->bitrate)
298 err = can_calc_bittiming(dev, bt, btc);
299 else if (bt->tq && !bt->bitrate)
300 err = can_fixup_bittiming(dev, bt, btc);
301 else
302 err = -EINVAL;
303
304 return err;
305}
306
307static void can_update_state_error_stats(struct net_device *dev,
308 enum can_state new_state)
309{
310 struct can_priv *priv = netdev_priv(dev);
311
312 if (new_state <= priv->state)
313 return;
314
315 switch (new_state) {
316 case CAN_STATE_ERROR_WARNING:
317 priv->can_stats.error_warning++;
318 break;
319 case CAN_STATE_ERROR_PASSIVE:
320 priv->can_stats.error_passive++;
321 break;
322 case CAN_STATE_BUS_OFF:
323 priv->can_stats.bus_off++;
324 break;
325 default:
326 break;
327 }
328}
329
330static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
331{
332 switch (state) {
333 case CAN_STATE_ERROR_ACTIVE:
334 return CAN_ERR_CRTL_ACTIVE;
335 case CAN_STATE_ERROR_WARNING:
336 return CAN_ERR_CRTL_TX_WARNING;
337 case CAN_STATE_ERROR_PASSIVE:
338 return CAN_ERR_CRTL_TX_PASSIVE;
339 default:
340 return 0;
341 }
342}
343
344static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
345{
346 switch (state) {
347 case CAN_STATE_ERROR_ACTIVE:
348 return CAN_ERR_CRTL_ACTIVE;
349 case CAN_STATE_ERROR_WARNING:
350 return CAN_ERR_CRTL_RX_WARNING;
351 case CAN_STATE_ERROR_PASSIVE:
352 return CAN_ERR_CRTL_RX_PASSIVE;
353 default:
354 return 0;
355 }
356}
357
358void can_change_state(struct net_device *dev, struct can_frame *cf,
359 enum can_state tx_state, enum can_state rx_state)
360{
361 struct can_priv *priv = netdev_priv(dev);
362 enum can_state new_state = max(tx_state, rx_state);
363
364 if (unlikely(new_state == priv->state)) {
365 netdev_warn(dev, "%s: oops, state did not change", __func__);
366 return;
367 }
368
369 netdev_dbg(dev, "New error state: %d\n", new_state);
370
371 can_update_state_error_stats(dev, new_state);
372 priv->state = new_state;
373
374 if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
375 cf->can_id |= CAN_ERR_BUSOFF;
376 return;
377 }
378
379 cf->can_id |= CAN_ERR_CRTL;
380 cf->data[1] |= tx_state >= rx_state ?
381 can_tx_state_to_frame(dev, tx_state) : 0;
382 cf->data[1] |= tx_state <= rx_state ?
383 can_rx_state_to_frame(dev, rx_state) : 0;
384}
385EXPORT_SYMBOL_GPL(can_change_state);
386
387/*
388 * Local echo of CAN messages
389 *
390 * CAN network devices *should* support a local echo functionality
391 * (see Documentation/networking/can.txt). To test the handling of CAN
392 * interfaces that do not support the local echo both driver types are
393 * implemented. In the case that the driver does not support the echo
394 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
395 * to perform the echo as a fallback solution.
396 */
397static void can_flush_echo_skb(struct net_device *dev)
398{
399 struct can_priv *priv = netdev_priv(dev);
400 struct net_device_stats *stats = &dev->stats;
401 int i;
402
403 for (i = 0; i < priv->echo_skb_max; i++) {
404 if (priv->echo_skb[i]) {
405 kfree_skb(priv->echo_skb[i]);
406 priv->echo_skb[i] = NULL;
407 stats->tx_dropped++;
408 stats->tx_aborted_errors++;
409 }
410 }
411}
412
413/*
414 * Put the skb on the stack to be looped backed locally lateron
415 *
416 * The function is typically called in the start_xmit function
417 * of the device driver. The driver must protect access to
418 * priv->echo_skb, if necessary.
419 */
420void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
421 unsigned int idx)
422{
423 struct can_priv *priv = netdev_priv(dev);
424
425 BUG_ON(idx >= priv->echo_skb_max);
426
427 /* check flag whether this packet has to be looped back */
428 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
429 (skb->protocol != htons(ETH_P_CAN) &&
430 skb->protocol != htons(ETH_P_CANFD))) {
431 kfree_skb(skb);
432 return;
433 }
434
435 if (!priv->echo_skb[idx]) {
436
437 skb = can_create_echo_skb(skb);
438 if (!skb)
439 return;
440
441 /* make settings for echo to reduce code in irq context */
442 skb->pkt_type = PACKET_BROADCAST;
443 skb->ip_summed = CHECKSUM_UNNECESSARY;
444 skb->dev = dev;
445
446 /* save this skb for tx interrupt echo handling */
447 priv->echo_skb[idx] = skb;
448 } else {
449 /* locking problem with netif_stop_queue() ?? */
450 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
451 kfree_skb(skb);
452 }
453}
454EXPORT_SYMBOL_GPL(can_put_echo_skb);
455
456/*
457 * Get the skb from the stack and loop it back locally
458 *
459 * The function is typically called when the TX done interrupt
460 * is handled in the device driver. The driver must protect
461 * access to priv->echo_skb, if necessary.
462 */
463unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
464{
465 struct can_priv *priv = netdev_priv(dev);
466
467 BUG_ON(idx >= priv->echo_skb_max);
468
469 if (priv->echo_skb[idx]) {
470 struct sk_buff *skb = priv->echo_skb[idx];
471 struct can_frame *cf = (struct can_frame *)skb->data;
472 u8 dlc = cf->can_dlc;
473
474 netif_rx(priv->echo_skb[idx]);
475 priv->echo_skb[idx] = NULL;
476
477 return dlc;
478 }
479
480 return 0;
481}
482EXPORT_SYMBOL_GPL(can_get_echo_skb);
483
484/*
485 * Remove the skb from the stack and free it.
486 *
487 * The function is typically called when TX failed.
488 */
489void can_free_echo_skb(struct net_device *dev, unsigned int idx)
490{
491 struct can_priv *priv = netdev_priv(dev);
492
493 BUG_ON(idx >= priv->echo_skb_max);
494
495 if (priv->echo_skb[idx]) {
496 dev_kfree_skb_any(priv->echo_skb[idx]);
497 priv->echo_skb[idx] = NULL;
498 }
499}
500EXPORT_SYMBOL_GPL(can_free_echo_skb);
501
502/*
503 * CAN device restart for bus-off recovery
504 */
505static void can_restart(struct net_device *dev)
506{
507 struct can_priv *priv = netdev_priv(dev);
508 struct net_device_stats *stats = &dev->stats;
509 struct sk_buff *skb;
510 struct can_frame *cf;
511 int err;
512
513 BUG_ON(netif_carrier_ok(dev));
514
515 /*
516 * No synchronization needed because the device is bus-off and
517 * no messages can come in or go out.
518 */
519 can_flush_echo_skb(dev);
520
521 /* send restart message upstream */
522 skb = alloc_can_err_skb(dev, &cf);
523 if (skb == NULL) {
524 err = -ENOMEM;
525 goto restart;
526 }
527 cf->can_id |= CAN_ERR_RESTARTED;
528
529 netif_rx(skb);
530
531 stats->rx_packets++;
532 stats->rx_bytes += cf->can_dlc;
533
534restart:
535 netdev_dbg(dev, "restarted\n");
536 priv->can_stats.restarts++;
537
538 /* Now restart the device */
539 err = priv->do_set_mode(dev, CAN_MODE_START);
540
541 netif_carrier_on(dev);
542 if (err)
543 netdev_err(dev, "Error %d during restart", err);
544}
545
546static void can_restart_work(struct work_struct *work)
547{
548 struct delayed_work *dwork = to_delayed_work(work);
549 struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
550
551 can_restart(priv->dev);
552}
553
554int can_restart_now(struct net_device *dev)
555{
556 struct can_priv *priv = netdev_priv(dev);
557
558 /*
559 * A manual restart is only permitted if automatic restart is
560 * disabled and the device is in the bus-off state
561 */
562 if (priv->restart_ms)
563 return -EINVAL;
564 if (priv->state != CAN_STATE_BUS_OFF)
565 return -EBUSY;
566
567 cancel_delayed_work_sync(&priv->restart_work);
568 can_restart(dev);
569
570 return 0;
571}
572
573/*
574 * CAN bus-off
575 *
576 * This functions should be called when the device goes bus-off to
577 * tell the netif layer that no more packets can be sent or received.
578 * If enabled, a timer is started to trigger bus-off recovery.
579 */
580void can_bus_off(struct net_device *dev)
581{
582 struct can_priv *priv = netdev_priv(dev);
583
584 netdev_dbg(dev, "bus-off\n");
585
586 netif_carrier_off(dev);
587
588 if (priv->restart_ms)
589 schedule_delayed_work(&priv->restart_work,
590 msecs_to_jiffies(priv->restart_ms));
591}
592EXPORT_SYMBOL_GPL(can_bus_off);
593
594static void can_setup(struct net_device *dev)
595{
596 dev->type = ARPHRD_CAN;
597 dev->mtu = CAN_MTU;
598 dev->hard_header_len = 0;
599 dev->addr_len = 0;
600 dev->tx_queue_len = 10;
601
602 /* New-style flags. */
603 dev->flags = IFF_NOARP;
604 dev->features = NETIF_F_HW_CSUM;
605}
606
607struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
608{
609 struct sk_buff *skb;
610
611 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
612 sizeof(struct can_frame));
613 if (unlikely(!skb))
614 return NULL;
615
616 skb->protocol = htons(ETH_P_CAN);
617 skb->pkt_type = PACKET_BROADCAST;
618 skb->ip_summed = CHECKSUM_UNNECESSARY;
619
620 skb_reset_mac_header(skb);
621 skb_reset_network_header(skb);
622 skb_reset_transport_header(skb);
623
624 can_skb_reserve(skb);
625 can_skb_prv(skb)->ifindex = dev->ifindex;
626 can_skb_prv(skb)->skbcnt = 0;
627
628 *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
629 memset(*cf, 0, sizeof(struct can_frame));
630
631 return skb;
632}
633EXPORT_SYMBOL_GPL(alloc_can_skb);
634
635struct sk_buff *alloc_canfd_skb(struct net_device *dev,
636 struct canfd_frame **cfd)
637{
638 struct sk_buff *skb;
639
640 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
641 sizeof(struct canfd_frame));
642 if (unlikely(!skb))
643 return NULL;
644
645 skb->protocol = htons(ETH_P_CANFD);
646 skb->pkt_type = PACKET_BROADCAST;
647 skb->ip_summed = CHECKSUM_UNNECESSARY;
648
649 skb_reset_mac_header(skb);
650 skb_reset_network_header(skb);
651 skb_reset_transport_header(skb);
652
653 can_skb_reserve(skb);
654 can_skb_prv(skb)->ifindex = dev->ifindex;
655 can_skb_prv(skb)->skbcnt = 0;
656
657 *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
658 memset(*cfd, 0, sizeof(struct canfd_frame));
659
660 return skb;
661}
662EXPORT_SYMBOL_GPL(alloc_canfd_skb);
663
664struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
665{
666 struct sk_buff *skb;
667
668 skb = alloc_can_skb(dev, cf);
669 if (unlikely(!skb))
670 return NULL;
671
672 (*cf)->can_id = CAN_ERR_FLAG;
673 (*cf)->can_dlc = CAN_ERR_DLC;
674
675 return skb;
676}
677EXPORT_SYMBOL_GPL(alloc_can_err_skb);
678
679/*
680 * Allocate and setup space for the CAN network device
681 */
682struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
683{
684 struct net_device *dev;
685 struct can_priv *priv;
686 int size;
687
688 if (echo_skb_max)
689 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
690 echo_skb_max * sizeof(struct sk_buff *);
691 else
692 size = sizeof_priv;
693
694 dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
695 if (!dev)
696 return NULL;
697
698 priv = netdev_priv(dev);
699 priv->dev = dev;
700
701 if (echo_skb_max) {
702 priv->echo_skb_max = echo_skb_max;
703 priv->echo_skb = (void *)priv +
704 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
705 }
706
707 priv->state = CAN_STATE_STOPPED;
708
709 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
710
711 return dev;
712}
713EXPORT_SYMBOL_GPL(alloc_candev);
714
715/*
716 * Free space of the CAN network device
717 */
718void free_candev(struct net_device *dev)
719{
720 free_netdev(dev);
721}
722EXPORT_SYMBOL_GPL(free_candev);
723
724/*
725 * changing MTU and control mode for CAN/CANFD devices
726 */
727int can_change_mtu(struct net_device *dev, int new_mtu)
728{
729 struct can_priv *priv = netdev_priv(dev);
730
731 /* Do not allow changing the MTU while running */
732 if (dev->flags & IFF_UP)
733 return -EBUSY;
734
735 /* allow change of MTU according to the CANFD ability of the device */
736 switch (new_mtu) {
737 case CAN_MTU:
738 /* 'CANFD-only' controllers can not switch to CAN_MTU */
739 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
740 return -EINVAL;
741
742 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
743 break;
744
745 case CANFD_MTU:
746 /* check for potential CANFD ability */
747 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
748 !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
749 return -EINVAL;
750
751 priv->ctrlmode |= CAN_CTRLMODE_FD;
752 break;
753
754 default:
755 return -EINVAL;
756 }
757
758 dev->mtu = new_mtu;
759 return 0;
760}
761EXPORT_SYMBOL_GPL(can_change_mtu);
762
763/*
764 * Common open function when the device gets opened.
765 *
766 * This function should be called in the open function of the device
767 * driver.
768 */
769int open_candev(struct net_device *dev)
770{
771 struct can_priv *priv = netdev_priv(dev);
772
773 if (!priv->bittiming.bitrate) {
774 netdev_err(dev, "bit-timing not yet defined\n");
775 return -EINVAL;
776 }
777
778 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
779 if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
780 (!priv->data_bittiming.bitrate ||
781 (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
782 netdev_err(dev, "incorrect/missing data bit-timing\n");
783 return -EINVAL;
784 }
785
786 /* Switch carrier on if device was stopped while in bus-off state */
787 if (!netif_carrier_ok(dev))
788 netif_carrier_on(dev);
789
790 return 0;
791}
792EXPORT_SYMBOL_GPL(open_candev);
793
794/*
795 * Common close function for cleanup before the device gets closed.
796 *
797 * This function should be called in the close function of the device
798 * driver.
799 */
800void close_candev(struct net_device *dev)
801{
802 struct can_priv *priv = netdev_priv(dev);
803
804 cancel_delayed_work_sync(&priv->restart_work);
805 can_flush_echo_skb(dev);
806}
807EXPORT_SYMBOL_GPL(close_candev);
808
809/*
810 * CAN netlink interface
811 */
812static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
813 [IFLA_CAN_STATE] = { .type = NLA_U32 },
814 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
815 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
816 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
817 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
818 [IFLA_CAN_BITTIMING_CONST]
819 = { .len = sizeof(struct can_bittiming_const) },
820 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
821 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
822 [IFLA_CAN_DATA_BITTIMING]
823 = { .len = sizeof(struct can_bittiming) },
824 [IFLA_CAN_DATA_BITTIMING_CONST]
825 = { .len = sizeof(struct can_bittiming_const) },
826};
827
828static int can_validate(struct nlattr *tb[], struct nlattr *data[])
829{
830 bool is_can_fd = false;
831
832 /* Make sure that valid CAN FD configurations always consist of
833 * - nominal/arbitration bittiming
834 * - data bittiming
835 * - control mode with CAN_CTRLMODE_FD set
836 */
837
838 if (!data)
839 return 0;
840
841 if (data[IFLA_CAN_CTRLMODE]) {
842 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
843
844 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
845 }
846
847 if (is_can_fd) {
848 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
849 return -EOPNOTSUPP;
850 }
851
852 if (data[IFLA_CAN_DATA_BITTIMING]) {
853 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
854 return -EOPNOTSUPP;
855 }
856
857 return 0;
858}
859
860static int can_changelink(struct net_device *dev,
861 struct nlattr *tb[], struct nlattr *data[])
862{
863 struct can_priv *priv = netdev_priv(dev);
864 int err;
865
866 /* We need synchronization with dev->stop() */
867 ASSERT_RTNL();
868
869 if (data[IFLA_CAN_BITTIMING]) {
870 struct can_bittiming bt;
871
872 /* Do not allow changing bittiming while running */
873 if (dev->flags & IFF_UP)
874 return -EBUSY;
875 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
876 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
877 if (err)
878 return err;
879 memcpy(&priv->bittiming, &bt, sizeof(bt));
880
881 if (priv->do_set_bittiming) {
882 /* Finally, set the bit-timing registers */
883 err = priv->do_set_bittiming(dev);
884 if (err)
885 return err;
886 }
887 }
888
889 if (data[IFLA_CAN_CTRLMODE]) {
890 struct can_ctrlmode *cm;
891 u32 ctrlstatic;
892 u32 maskedflags;
893
894 /* Do not allow changing controller mode while running */
895 if (dev->flags & IFF_UP)
896 return -EBUSY;
897 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
898 ctrlstatic = priv->ctrlmode_static;
899 maskedflags = cm->flags & cm->mask;
900
901 /* check whether provided bits are allowed to be passed */
902 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
903 return -EOPNOTSUPP;
904
905 /* do not check for static fd-non-iso if 'fd' is disabled */
906 if (!(maskedflags & CAN_CTRLMODE_FD))
907 ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
908
909 /* make sure static options are provided by configuration */
910 if ((maskedflags & ctrlstatic) != ctrlstatic)
911 return -EOPNOTSUPP;
912
913 /* clear bits to be modified and copy the flag values */
914 priv->ctrlmode &= ~cm->mask;
915 priv->ctrlmode |= maskedflags;
916
917 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
918 if (priv->ctrlmode & CAN_CTRLMODE_FD)
919 dev->mtu = CANFD_MTU;
920 else
921 dev->mtu = CAN_MTU;
922 }
923
924 if (data[IFLA_CAN_RESTART_MS]) {
925 /* Do not allow changing restart delay while running */
926 if (dev->flags & IFF_UP)
927 return -EBUSY;
928 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
929 }
930
931 if (data[IFLA_CAN_RESTART]) {
932 /* Do not allow a restart while not running */
933 if (!(dev->flags & IFF_UP))
934 return -EINVAL;
935 err = can_restart_now(dev);
936 if (err)
937 return err;
938 }
939
940 if (data[IFLA_CAN_DATA_BITTIMING]) {
941 struct can_bittiming dbt;
942
943 /* Do not allow changing bittiming while running */
944 if (dev->flags & IFF_UP)
945 return -EBUSY;
946 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
947 sizeof(dbt));
948 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
949 if (err)
950 return err;
951 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
952
953 if (priv->do_set_data_bittiming) {
954 /* Finally, set the bit-timing registers */
955 err = priv->do_set_data_bittiming(dev);
956 if (err)
957 return err;
958 }
959 }
960
961 return 0;
962}
963
964static size_t can_get_size(const struct net_device *dev)
965{
966 struct can_priv *priv = netdev_priv(dev);
967 size_t size = 0;
968
969 if (priv->bittiming.bitrate) /* IFLA_CAN_BITTIMING */
970 size += nla_total_size(sizeof(struct can_bittiming));
971 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
972 size += nla_total_size(sizeof(struct can_bittiming_const));
973 size += nla_total_size(sizeof(struct can_clock)); /* IFLA_CAN_CLOCK */
974 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
975 size += nla_total_size(sizeof(struct can_ctrlmode)); /* IFLA_CAN_CTRLMODE */
976 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
977 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
978 size += nla_total_size(sizeof(struct can_berr_counter));
979 if (priv->data_bittiming.bitrate) /* IFLA_CAN_DATA_BITTIMING */
980 size += nla_total_size(sizeof(struct can_bittiming));
981 if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */
982 size += nla_total_size(sizeof(struct can_bittiming_const));
983
984 return size;
985}
986
987static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
988{
989 struct can_priv *priv = netdev_priv(dev);
990 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
991 struct can_berr_counter bec;
992 enum can_state state = priv->state;
993
994 if (priv->do_get_state)
995 priv->do_get_state(dev, &state);
996
997 if ((priv->bittiming.bitrate &&
998 nla_put(skb, IFLA_CAN_BITTIMING,
999 sizeof(priv->bittiming), &priv->bittiming)) ||
1000
1001 (priv->bittiming_const &&
1002 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1003 sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1004
1005 nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1006 nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1007 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1008 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1009
1010 (priv->do_get_berr_counter &&
1011 !priv->do_get_berr_counter(dev, &bec) &&
1012 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1013
1014 (priv->data_bittiming.bitrate &&
1015 nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1016 sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1017
1018 (priv->data_bittiming_const &&
1019 nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1020 sizeof(*priv->data_bittiming_const),
1021 priv->data_bittiming_const)))
1022 return -EMSGSIZE;
1023
1024 return 0;
1025}
1026
1027static size_t can_get_xstats_size(const struct net_device *dev)
1028{
1029 return sizeof(struct can_device_stats);
1030}
1031
1032static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1033{
1034 struct can_priv *priv = netdev_priv(dev);
1035
1036 if (nla_put(skb, IFLA_INFO_XSTATS,
1037 sizeof(priv->can_stats), &priv->can_stats))
1038 goto nla_put_failure;
1039 return 0;
1040
1041nla_put_failure:
1042 return -EMSGSIZE;
1043}
1044
1045static int can_newlink(struct net *src_net, struct net_device *dev,
1046 struct nlattr *tb[], struct nlattr *data[])
1047{
1048 return -EOPNOTSUPP;
1049}
1050
1051static void can_dellink(struct net_device *dev, struct list_head *head)
1052{
1053 return;
1054}
1055
1056static struct rtnl_link_ops can_link_ops __read_mostly = {
1057 .kind = "can",
1058 .maxtype = IFLA_CAN_MAX,
1059 .policy = can_policy,
1060 .setup = can_setup,
1061 .validate = can_validate,
1062 .newlink = can_newlink,
1063 .changelink = can_changelink,
1064 .dellink = can_dellink,
1065 .get_size = can_get_size,
1066 .fill_info = can_fill_info,
1067 .get_xstats_size = can_get_xstats_size,
1068 .fill_xstats = can_fill_xstats,
1069};
1070
1071/*
1072 * Register the CAN network device
1073 */
1074int register_candev(struct net_device *dev)
1075{
1076 dev->rtnl_link_ops = &can_link_ops;
1077 return register_netdev(dev);
1078}
1079EXPORT_SYMBOL_GPL(register_candev);
1080
1081/*
1082 * Unregister the CAN network device
1083 */
1084void unregister_candev(struct net_device *dev)
1085{
1086 unregister_netdev(dev);
1087}
1088EXPORT_SYMBOL_GPL(unregister_candev);
1089
1090/*
1091 * Test if a network device is a candev based device
1092 * and return the can_priv* if so.
1093 */
1094struct can_priv *safe_candev_priv(struct net_device *dev)
1095{
1096 if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1097 return NULL;
1098
1099 return netdev_priv(dev);
1100}
1101EXPORT_SYMBOL_GPL(safe_candev_priv);
1102
1103static __init int can_dev_init(void)
1104{
1105 int err;
1106
1107 can_led_notifier_init();
1108
1109 err = rtnl_link_register(&can_link_ops);
1110 if (!err)
1111 printk(KERN_INFO MOD_DESC "\n");
1112
1113 return err;
1114}
1115module_init(can_dev_init);
1116
1117static __exit void can_dev_exit(void)
1118{
1119 rtnl_link_unregister(&can_link_ops);
1120
1121 can_led_notifier_exit();
1122}
1123module_exit(can_dev_exit);
1124
1125MODULE_ALIAS_RTNL_LINK("can");