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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 <linux/of.h>
31#include <net/rtnetlink.h>
32
33#define MOD_DESC "CAN device driver interface"
34
35MODULE_DESCRIPTION(MOD_DESC);
36MODULE_LICENSE("GPL v2");
37MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
38
39/* CAN DLC to real data length conversion helpers */
40
41static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
42 8, 12, 16, 20, 24, 32, 48, 64};
43
44/* get data length from can_dlc with sanitized can_dlc */
45u8 can_dlc2len(u8 can_dlc)
46{
47 return dlc2len[can_dlc & 0x0F];
48}
49EXPORT_SYMBOL_GPL(can_dlc2len);
50
51static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, /* 0 - 8 */
52 9, 9, 9, 9, /* 9 - 12 */
53 10, 10, 10, 10, /* 13 - 16 */
54 11, 11, 11, 11, /* 17 - 20 */
55 12, 12, 12, 12, /* 21 - 24 */
56 13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
57 14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
58 14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
59 15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
60 15, 15, 15, 15, 15, 15, 15, 15}; /* 57 - 64 */
61
62/* map the sanitized data length to an appropriate data length code */
63u8 can_len2dlc(u8 len)
64{
65 if (unlikely(len > 64))
66 return 0xF;
67
68 return len2dlc[len];
69}
70EXPORT_SYMBOL_GPL(can_len2dlc);
71
72#ifdef CONFIG_CAN_CALC_BITTIMING
73#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
74#define CAN_CALC_SYNC_SEG 1
75
76/*
77 * Bit-timing calculation derived from:
78 *
79 * Code based on LinCAN sources and H8S2638 project
80 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
81 * Copyright 2005 Stanislav Marek
82 * email: pisa@cmp.felk.cvut.cz
83 *
84 * Calculates proper bit-timing parameters for a specified bit-rate
85 * and sample-point, which can then be used to set the bit-timing
86 * registers of the CAN controller. You can find more information
87 * in the header file linux/can/netlink.h.
88 */
89static int can_update_sample_point(const struct can_bittiming_const *btc,
90 unsigned int sample_point_nominal, unsigned int tseg,
91 unsigned int *tseg1_ptr, unsigned int *tseg2_ptr,
92 unsigned int *sample_point_error_ptr)
93{
94 unsigned int sample_point_error, best_sample_point_error = UINT_MAX;
95 unsigned int sample_point, best_sample_point = 0;
96 unsigned int tseg1, tseg2;
97 int i;
98
99 for (i = 0; i <= 1; i++) {
100 tseg2 = tseg + CAN_CALC_SYNC_SEG - (sample_point_nominal * (tseg + CAN_CALC_SYNC_SEG)) / 1000 - i;
101 tseg2 = clamp(tseg2, btc->tseg2_min, btc->tseg2_max);
102 tseg1 = tseg - tseg2;
103 if (tseg1 > btc->tseg1_max) {
104 tseg1 = btc->tseg1_max;
105 tseg2 = tseg - tseg1;
106 }
107
108 sample_point = 1000 * (tseg + CAN_CALC_SYNC_SEG - tseg2) / (tseg + CAN_CALC_SYNC_SEG);
109 sample_point_error = abs(sample_point_nominal - sample_point);
110
111 if ((sample_point <= sample_point_nominal) && (sample_point_error < best_sample_point_error)) {
112 best_sample_point = sample_point;
113 best_sample_point_error = sample_point_error;
114 *tseg1_ptr = tseg1;
115 *tseg2_ptr = tseg2;
116 }
117 }
118
119 if (sample_point_error_ptr)
120 *sample_point_error_ptr = best_sample_point_error;
121
122 return best_sample_point;
123}
124
125static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
126 const struct can_bittiming_const *btc)
127{
128 struct can_priv *priv = netdev_priv(dev);
129 unsigned int bitrate; /* current bitrate */
130 unsigned int bitrate_error; /* difference between current and nominal value */
131 unsigned int best_bitrate_error = UINT_MAX;
132 unsigned int sample_point_error; /* difference between current and nominal value */
133 unsigned int best_sample_point_error = UINT_MAX;
134 unsigned int sample_point_nominal; /* nominal sample point */
135 unsigned int best_tseg = 0; /* current best value for tseg */
136 unsigned int best_brp = 0; /* current best value for brp */
137 unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0;
138 u64 v64;
139
140 /* Use CiA recommended sample points */
141 if (bt->sample_point) {
142 sample_point_nominal = bt->sample_point;
143 } else {
144 if (bt->bitrate > 800000)
145 sample_point_nominal = 750;
146 else if (bt->bitrate > 500000)
147 sample_point_nominal = 800;
148 else
149 sample_point_nominal = 875;
150 }
151
152 /* tseg even = round down, odd = round up */
153 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
154 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
155 tsegall = CAN_CALC_SYNC_SEG + tseg / 2;
156
157 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
158 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
159
160 /* choose brp step which is possible in system */
161 brp = (brp / btc->brp_inc) * btc->brp_inc;
162 if ((brp < btc->brp_min) || (brp > btc->brp_max))
163 continue;
164
165 bitrate = priv->clock.freq / (brp * tsegall);
166 bitrate_error = abs(bt->bitrate - bitrate);
167
168 /* tseg brp biterror */
169 if (bitrate_error > best_bitrate_error)
170 continue;
171
172 /* reset sample point error if we have a better bitrate */
173 if (bitrate_error < best_bitrate_error)
174 best_sample_point_error = UINT_MAX;
175
176 can_update_sample_point(btc, sample_point_nominal, tseg / 2, &tseg1, &tseg2, &sample_point_error);
177 if (sample_point_error > best_sample_point_error)
178 continue;
179
180 best_sample_point_error = sample_point_error;
181 best_bitrate_error = bitrate_error;
182 best_tseg = tseg / 2;
183 best_brp = brp;
184
185 if (bitrate_error == 0 && sample_point_error == 0)
186 break;
187 }
188
189 if (best_bitrate_error) {
190 /* Error in one-tenth of a percent */
191 v64 = (u64)best_bitrate_error * 1000;
192 do_div(v64, bt->bitrate);
193 bitrate_error = (u32)v64;
194 if (bitrate_error > CAN_CALC_MAX_ERROR) {
195 netdev_err(dev,
196 "bitrate error %d.%d%% too high\n",
197 bitrate_error / 10, bitrate_error % 10);
198 return -EDOM;
199 }
200 netdev_warn(dev, "bitrate error %d.%d%%\n",
201 bitrate_error / 10, bitrate_error % 10);
202 }
203
204 /* real sample point */
205 bt->sample_point = can_update_sample_point(btc, sample_point_nominal, best_tseg,
206 &tseg1, &tseg2, NULL);
207
208 v64 = (u64)best_brp * 1000 * 1000 * 1000;
209 do_div(v64, priv->clock.freq);
210 bt->tq = (u32)v64;
211 bt->prop_seg = tseg1 / 2;
212 bt->phase_seg1 = tseg1 - bt->prop_seg;
213 bt->phase_seg2 = tseg2;
214
215 /* check for sjw user settings */
216 if (!bt->sjw || !btc->sjw_max) {
217 bt->sjw = 1;
218 } else {
219 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
220 if (bt->sjw > btc->sjw_max)
221 bt->sjw = btc->sjw_max;
222 /* bt->sjw must not be higher than tseg2 */
223 if (tseg2 < bt->sjw)
224 bt->sjw = tseg2;
225 }
226
227 bt->brp = best_brp;
228
229 /* real bitrate */
230 bt->bitrate = priv->clock.freq / (bt->brp * (CAN_CALC_SYNC_SEG + tseg1 + tseg2));
231
232 return 0;
233}
234#else /* !CONFIG_CAN_CALC_BITTIMING */
235static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
236 const struct can_bittiming_const *btc)
237{
238 netdev_err(dev, "bit-timing calculation not available\n");
239 return -EINVAL;
240}
241#endif /* CONFIG_CAN_CALC_BITTIMING */
242
243/*
244 * Checks the validity of the specified bit-timing parameters prop_seg,
245 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
246 * prescaler value brp. You can find more information in the header
247 * file linux/can/netlink.h.
248 */
249static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
250 const struct can_bittiming_const *btc)
251{
252 struct can_priv *priv = netdev_priv(dev);
253 int tseg1, alltseg;
254 u64 brp64;
255
256 tseg1 = bt->prop_seg + bt->phase_seg1;
257 if (!bt->sjw)
258 bt->sjw = 1;
259 if (bt->sjw > btc->sjw_max ||
260 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
261 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
262 return -ERANGE;
263
264 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
265 if (btc->brp_inc > 1)
266 do_div(brp64, btc->brp_inc);
267 brp64 += 500000000UL - 1;
268 do_div(brp64, 1000000000UL); /* the practicable BRP */
269 if (btc->brp_inc > 1)
270 brp64 *= btc->brp_inc;
271 bt->brp = (u32)brp64;
272
273 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
274 return -EINVAL;
275
276 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
277 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
278 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
279
280 return 0;
281}
282
283/* Checks the validity of predefined bitrate settings */
284static int can_validate_bitrate(struct net_device *dev, struct can_bittiming *bt,
285 const u32 *bitrate_const,
286 const unsigned int bitrate_const_cnt)
287{
288 struct can_priv *priv = netdev_priv(dev);
289 unsigned int i;
290
291 for (i = 0; i < bitrate_const_cnt; i++) {
292 if (bt->bitrate == bitrate_const[i])
293 break;
294 }
295
296 if (i >= priv->bitrate_const_cnt)
297 return -EINVAL;
298
299 return 0;
300}
301
302static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
303 const struct can_bittiming_const *btc,
304 const u32 *bitrate_const,
305 const unsigned int bitrate_const_cnt)
306{
307 int err;
308
309 /*
310 * Depending on the given can_bittiming parameter structure the CAN
311 * timing parameters are calculated based on the provided bitrate OR
312 * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
313 * provided directly which are then checked and fixed up.
314 */
315 if (!bt->tq && bt->bitrate && btc)
316 err = can_calc_bittiming(dev, bt, btc);
317 else if (bt->tq && !bt->bitrate && btc)
318 err = can_fixup_bittiming(dev, bt, btc);
319 else if (!bt->tq && bt->bitrate && bitrate_const)
320 err = can_validate_bitrate(dev, bt, bitrate_const,
321 bitrate_const_cnt);
322 else
323 err = -EINVAL;
324
325 return err;
326}
327
328static void can_update_state_error_stats(struct net_device *dev,
329 enum can_state new_state)
330{
331 struct can_priv *priv = netdev_priv(dev);
332
333 if (new_state <= priv->state)
334 return;
335
336 switch (new_state) {
337 case CAN_STATE_ERROR_WARNING:
338 priv->can_stats.error_warning++;
339 break;
340 case CAN_STATE_ERROR_PASSIVE:
341 priv->can_stats.error_passive++;
342 break;
343 case CAN_STATE_BUS_OFF:
344 priv->can_stats.bus_off++;
345 break;
346 default:
347 break;
348 }
349}
350
351static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
352{
353 switch (state) {
354 case CAN_STATE_ERROR_ACTIVE:
355 return CAN_ERR_CRTL_ACTIVE;
356 case CAN_STATE_ERROR_WARNING:
357 return CAN_ERR_CRTL_TX_WARNING;
358 case CAN_STATE_ERROR_PASSIVE:
359 return CAN_ERR_CRTL_TX_PASSIVE;
360 default:
361 return 0;
362 }
363}
364
365static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
366{
367 switch (state) {
368 case CAN_STATE_ERROR_ACTIVE:
369 return CAN_ERR_CRTL_ACTIVE;
370 case CAN_STATE_ERROR_WARNING:
371 return CAN_ERR_CRTL_RX_WARNING;
372 case CAN_STATE_ERROR_PASSIVE:
373 return CAN_ERR_CRTL_RX_PASSIVE;
374 default:
375 return 0;
376 }
377}
378
379void can_change_state(struct net_device *dev, struct can_frame *cf,
380 enum can_state tx_state, enum can_state rx_state)
381{
382 struct can_priv *priv = netdev_priv(dev);
383 enum can_state new_state = max(tx_state, rx_state);
384
385 if (unlikely(new_state == priv->state)) {
386 netdev_warn(dev, "%s: oops, state did not change", __func__);
387 return;
388 }
389
390 netdev_dbg(dev, "New error state: %d\n", new_state);
391
392 can_update_state_error_stats(dev, new_state);
393 priv->state = new_state;
394
395 if (!cf)
396 return;
397
398 if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
399 cf->can_id |= CAN_ERR_BUSOFF;
400 return;
401 }
402
403 cf->can_id |= CAN_ERR_CRTL;
404 cf->data[1] |= tx_state >= rx_state ?
405 can_tx_state_to_frame(dev, tx_state) : 0;
406 cf->data[1] |= tx_state <= rx_state ?
407 can_rx_state_to_frame(dev, rx_state) : 0;
408}
409EXPORT_SYMBOL_GPL(can_change_state);
410
411/*
412 * Local echo of CAN messages
413 *
414 * CAN network devices *should* support a local echo functionality
415 * (see Documentation/networking/can.rst). To test the handling of CAN
416 * interfaces that do not support the local echo both driver types are
417 * implemented. In the case that the driver does not support the echo
418 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
419 * to perform the echo as a fallback solution.
420 */
421static void can_flush_echo_skb(struct net_device *dev)
422{
423 struct can_priv *priv = netdev_priv(dev);
424 struct net_device_stats *stats = &dev->stats;
425 int i;
426
427 for (i = 0; i < priv->echo_skb_max; i++) {
428 if (priv->echo_skb[i]) {
429 kfree_skb(priv->echo_skb[i]);
430 priv->echo_skb[i] = NULL;
431 stats->tx_dropped++;
432 stats->tx_aborted_errors++;
433 }
434 }
435}
436
437/*
438 * Put the skb on the stack to be looped backed locally lateron
439 *
440 * The function is typically called in the start_xmit function
441 * of the device driver. The driver must protect access to
442 * priv->echo_skb, if necessary.
443 */
444void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
445 unsigned int idx)
446{
447 struct can_priv *priv = netdev_priv(dev);
448
449 BUG_ON(idx >= priv->echo_skb_max);
450
451 /* check flag whether this packet has to be looped back */
452 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
453 (skb->protocol != htons(ETH_P_CAN) &&
454 skb->protocol != htons(ETH_P_CANFD))) {
455 kfree_skb(skb);
456 return;
457 }
458
459 if (!priv->echo_skb[idx]) {
460
461 skb = can_create_echo_skb(skb);
462 if (!skb)
463 return;
464
465 /* make settings for echo to reduce code in irq context */
466 skb->pkt_type = PACKET_BROADCAST;
467 skb->ip_summed = CHECKSUM_UNNECESSARY;
468 skb->dev = dev;
469
470 /* save this skb for tx interrupt echo handling */
471 priv->echo_skb[idx] = skb;
472 } else {
473 /* locking problem with netif_stop_queue() ?? */
474 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
475 kfree_skb(skb);
476 }
477}
478EXPORT_SYMBOL_GPL(can_put_echo_skb);
479
480/*
481 * Get the skb from the stack and loop it back locally
482 *
483 * The function is typically called when the TX done interrupt
484 * is handled in the device driver. The driver must protect
485 * access to priv->echo_skb, if necessary.
486 */
487unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
488{
489 struct can_priv *priv = netdev_priv(dev);
490
491 BUG_ON(idx >= priv->echo_skb_max);
492
493 if (priv->echo_skb[idx]) {
494 struct sk_buff *skb = priv->echo_skb[idx];
495 struct can_frame *cf = (struct can_frame *)skb->data;
496 u8 dlc = cf->can_dlc;
497
498 netif_rx(priv->echo_skb[idx]);
499 priv->echo_skb[idx] = NULL;
500
501 return dlc;
502 }
503
504 return 0;
505}
506EXPORT_SYMBOL_GPL(can_get_echo_skb);
507
508/*
509 * Remove the skb from the stack and free it.
510 *
511 * The function is typically called when TX failed.
512 */
513void can_free_echo_skb(struct net_device *dev, unsigned int idx)
514{
515 struct can_priv *priv = netdev_priv(dev);
516
517 BUG_ON(idx >= priv->echo_skb_max);
518
519 if (priv->echo_skb[idx]) {
520 dev_kfree_skb_any(priv->echo_skb[idx]);
521 priv->echo_skb[idx] = NULL;
522 }
523}
524EXPORT_SYMBOL_GPL(can_free_echo_skb);
525
526/*
527 * CAN device restart for bus-off recovery
528 */
529static void can_restart(struct net_device *dev)
530{
531 struct can_priv *priv = netdev_priv(dev);
532 struct net_device_stats *stats = &dev->stats;
533 struct sk_buff *skb;
534 struct can_frame *cf;
535 int err;
536
537 BUG_ON(netif_carrier_ok(dev));
538
539 /*
540 * No synchronization needed because the device is bus-off and
541 * no messages can come in or go out.
542 */
543 can_flush_echo_skb(dev);
544
545 /* send restart message upstream */
546 skb = alloc_can_err_skb(dev, &cf);
547 if (skb == NULL) {
548 err = -ENOMEM;
549 goto restart;
550 }
551 cf->can_id |= CAN_ERR_RESTARTED;
552
553 netif_rx(skb);
554
555 stats->rx_packets++;
556 stats->rx_bytes += cf->can_dlc;
557
558restart:
559 netdev_dbg(dev, "restarted\n");
560 priv->can_stats.restarts++;
561
562 /* Now restart the device */
563 err = priv->do_set_mode(dev, CAN_MODE_START);
564
565 netif_carrier_on(dev);
566 if (err)
567 netdev_err(dev, "Error %d during restart", err);
568}
569
570static void can_restart_work(struct work_struct *work)
571{
572 struct delayed_work *dwork = to_delayed_work(work);
573 struct can_priv *priv = container_of(dwork, struct can_priv, restart_work);
574
575 can_restart(priv->dev);
576}
577
578int can_restart_now(struct net_device *dev)
579{
580 struct can_priv *priv = netdev_priv(dev);
581
582 /*
583 * A manual restart is only permitted if automatic restart is
584 * disabled and the device is in the bus-off state
585 */
586 if (priv->restart_ms)
587 return -EINVAL;
588 if (priv->state != CAN_STATE_BUS_OFF)
589 return -EBUSY;
590
591 cancel_delayed_work_sync(&priv->restart_work);
592 can_restart(dev);
593
594 return 0;
595}
596
597/*
598 * CAN bus-off
599 *
600 * This functions should be called when the device goes bus-off to
601 * tell the netif layer that no more packets can be sent or received.
602 * If enabled, a timer is started to trigger bus-off recovery.
603 */
604void can_bus_off(struct net_device *dev)
605{
606 struct can_priv *priv = netdev_priv(dev);
607
608 netdev_info(dev, "bus-off\n");
609
610 netif_carrier_off(dev);
611
612 if (priv->restart_ms)
613 schedule_delayed_work(&priv->restart_work,
614 msecs_to_jiffies(priv->restart_ms));
615}
616EXPORT_SYMBOL_GPL(can_bus_off);
617
618static void can_setup(struct net_device *dev)
619{
620 dev->type = ARPHRD_CAN;
621 dev->mtu = CAN_MTU;
622 dev->hard_header_len = 0;
623 dev->addr_len = 0;
624 dev->tx_queue_len = 10;
625
626 /* New-style flags. */
627 dev->flags = IFF_NOARP;
628 dev->features = NETIF_F_HW_CSUM;
629}
630
631struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
632{
633 struct sk_buff *skb;
634
635 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
636 sizeof(struct can_frame));
637 if (unlikely(!skb))
638 return NULL;
639
640 skb->protocol = htons(ETH_P_CAN);
641 skb->pkt_type = PACKET_BROADCAST;
642 skb->ip_summed = CHECKSUM_UNNECESSARY;
643
644 skb_reset_mac_header(skb);
645 skb_reset_network_header(skb);
646 skb_reset_transport_header(skb);
647
648 can_skb_reserve(skb);
649 can_skb_prv(skb)->ifindex = dev->ifindex;
650 can_skb_prv(skb)->skbcnt = 0;
651
652 *cf = skb_put(skb, sizeof(struct can_frame));
653 memset(*cf, 0, sizeof(struct can_frame));
654
655 return skb;
656}
657EXPORT_SYMBOL_GPL(alloc_can_skb);
658
659struct sk_buff *alloc_canfd_skb(struct net_device *dev,
660 struct canfd_frame **cfd)
661{
662 struct sk_buff *skb;
663
664 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
665 sizeof(struct canfd_frame));
666 if (unlikely(!skb))
667 return NULL;
668
669 skb->protocol = htons(ETH_P_CANFD);
670 skb->pkt_type = PACKET_BROADCAST;
671 skb->ip_summed = CHECKSUM_UNNECESSARY;
672
673 skb_reset_mac_header(skb);
674 skb_reset_network_header(skb);
675 skb_reset_transport_header(skb);
676
677 can_skb_reserve(skb);
678 can_skb_prv(skb)->ifindex = dev->ifindex;
679 can_skb_prv(skb)->skbcnt = 0;
680
681 *cfd = skb_put(skb, sizeof(struct canfd_frame));
682 memset(*cfd, 0, sizeof(struct canfd_frame));
683
684 return skb;
685}
686EXPORT_SYMBOL_GPL(alloc_canfd_skb);
687
688struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
689{
690 struct sk_buff *skb;
691
692 skb = alloc_can_skb(dev, cf);
693 if (unlikely(!skb))
694 return NULL;
695
696 (*cf)->can_id = CAN_ERR_FLAG;
697 (*cf)->can_dlc = CAN_ERR_DLC;
698
699 return skb;
700}
701EXPORT_SYMBOL_GPL(alloc_can_err_skb);
702
703/*
704 * Allocate and setup space for the CAN network device
705 */
706struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
707{
708 struct net_device *dev;
709 struct can_priv *priv;
710 int size;
711
712 if (echo_skb_max)
713 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
714 echo_skb_max * sizeof(struct sk_buff *);
715 else
716 size = sizeof_priv;
717
718 dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
719 if (!dev)
720 return NULL;
721
722 priv = netdev_priv(dev);
723 priv->dev = dev;
724
725 if (echo_skb_max) {
726 priv->echo_skb_max = echo_skb_max;
727 priv->echo_skb = (void *)priv +
728 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
729 }
730
731 priv->state = CAN_STATE_STOPPED;
732
733 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
734
735 return dev;
736}
737EXPORT_SYMBOL_GPL(alloc_candev);
738
739/*
740 * Free space of the CAN network device
741 */
742void free_candev(struct net_device *dev)
743{
744 free_netdev(dev);
745}
746EXPORT_SYMBOL_GPL(free_candev);
747
748/*
749 * changing MTU and control mode for CAN/CANFD devices
750 */
751int can_change_mtu(struct net_device *dev, int new_mtu)
752{
753 struct can_priv *priv = netdev_priv(dev);
754
755 /* Do not allow changing the MTU while running */
756 if (dev->flags & IFF_UP)
757 return -EBUSY;
758
759 /* allow change of MTU according to the CANFD ability of the device */
760 switch (new_mtu) {
761 case CAN_MTU:
762 /* 'CANFD-only' controllers can not switch to CAN_MTU */
763 if (priv->ctrlmode_static & CAN_CTRLMODE_FD)
764 return -EINVAL;
765
766 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
767 break;
768
769 case CANFD_MTU:
770 /* check for potential CANFD ability */
771 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
772 !(priv->ctrlmode_static & CAN_CTRLMODE_FD))
773 return -EINVAL;
774
775 priv->ctrlmode |= CAN_CTRLMODE_FD;
776 break;
777
778 default:
779 return -EINVAL;
780 }
781
782 dev->mtu = new_mtu;
783 return 0;
784}
785EXPORT_SYMBOL_GPL(can_change_mtu);
786
787/*
788 * Common open function when the device gets opened.
789 *
790 * This function should be called in the open function of the device
791 * driver.
792 */
793int open_candev(struct net_device *dev)
794{
795 struct can_priv *priv = netdev_priv(dev);
796
797 if (!priv->bittiming.bitrate) {
798 netdev_err(dev, "bit-timing not yet defined\n");
799 return -EINVAL;
800 }
801
802 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
803 if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
804 (!priv->data_bittiming.bitrate ||
805 (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
806 netdev_err(dev, "incorrect/missing data bit-timing\n");
807 return -EINVAL;
808 }
809
810 /* Switch carrier on if device was stopped while in bus-off state */
811 if (!netif_carrier_ok(dev))
812 netif_carrier_on(dev);
813
814 return 0;
815}
816EXPORT_SYMBOL_GPL(open_candev);
817
818#ifdef CONFIG_OF
819/* Common function that can be used to understand the limitation of
820 * a transceiver when it provides no means to determine these limitations
821 * at runtime.
822 */
823void of_can_transceiver(struct net_device *dev)
824{
825 struct device_node *dn;
826 struct can_priv *priv = netdev_priv(dev);
827 struct device_node *np = dev->dev.parent->of_node;
828 int ret;
829
830 dn = of_get_child_by_name(np, "can-transceiver");
831 if (!dn)
832 return;
833
834 ret = of_property_read_u32(dn, "max-bitrate", &priv->bitrate_max);
835 if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
836 netdev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
837}
838EXPORT_SYMBOL_GPL(of_can_transceiver);
839#endif
840
841/*
842 * Common close function for cleanup before the device gets closed.
843 *
844 * This function should be called in the close function of the device
845 * driver.
846 */
847void close_candev(struct net_device *dev)
848{
849 struct can_priv *priv = netdev_priv(dev);
850
851 cancel_delayed_work_sync(&priv->restart_work);
852 can_flush_echo_skb(dev);
853}
854EXPORT_SYMBOL_GPL(close_candev);
855
856/*
857 * CAN netlink interface
858 */
859static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
860 [IFLA_CAN_STATE] = { .type = NLA_U32 },
861 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
862 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
863 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
864 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
865 [IFLA_CAN_BITTIMING_CONST]
866 = { .len = sizeof(struct can_bittiming_const) },
867 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
868 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
869 [IFLA_CAN_DATA_BITTIMING]
870 = { .len = sizeof(struct can_bittiming) },
871 [IFLA_CAN_DATA_BITTIMING_CONST]
872 = { .len = sizeof(struct can_bittiming_const) },
873};
874
875static int can_validate(struct nlattr *tb[], struct nlattr *data[],
876 struct netlink_ext_ack *extack)
877{
878 bool is_can_fd = false;
879
880 /* Make sure that valid CAN FD configurations always consist of
881 * - nominal/arbitration bittiming
882 * - data bittiming
883 * - control mode with CAN_CTRLMODE_FD set
884 */
885
886 if (!data)
887 return 0;
888
889 if (data[IFLA_CAN_CTRLMODE]) {
890 struct can_ctrlmode *cm = nla_data(data[IFLA_CAN_CTRLMODE]);
891
892 is_can_fd = cm->flags & cm->mask & CAN_CTRLMODE_FD;
893 }
894
895 if (is_can_fd) {
896 if (!data[IFLA_CAN_BITTIMING] || !data[IFLA_CAN_DATA_BITTIMING])
897 return -EOPNOTSUPP;
898 }
899
900 if (data[IFLA_CAN_DATA_BITTIMING]) {
901 if (!is_can_fd || !data[IFLA_CAN_BITTIMING])
902 return -EOPNOTSUPP;
903 }
904
905 return 0;
906}
907
908static int can_changelink(struct net_device *dev, struct nlattr *tb[],
909 struct nlattr *data[],
910 struct netlink_ext_ack *extack)
911{
912 struct can_priv *priv = netdev_priv(dev);
913 int err;
914
915 /* We need synchronization with dev->stop() */
916 ASSERT_RTNL();
917
918 if (data[IFLA_CAN_BITTIMING]) {
919 struct can_bittiming bt;
920
921 /* Do not allow changing bittiming while running */
922 if (dev->flags & IFF_UP)
923 return -EBUSY;
924
925 /* Calculate bittiming parameters based on
926 * bittiming_const if set, otherwise pass bitrate
927 * directly via do_set_bitrate(). Bail out if neither
928 * is given.
929 */
930 if (!priv->bittiming_const && !priv->do_set_bittiming)
931 return -EOPNOTSUPP;
932
933 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
934 err = can_get_bittiming(dev, &bt,
935 priv->bittiming_const,
936 priv->bitrate_const,
937 priv->bitrate_const_cnt);
938 if (err)
939 return err;
940
941 if (priv->bitrate_max && bt.bitrate > priv->bitrate_max) {
942 netdev_err(dev, "arbitration bitrate surpasses transceiver capabilities of %d bps\n",
943 priv->bitrate_max);
944 return -EINVAL;
945 }
946
947 memcpy(&priv->bittiming, &bt, sizeof(bt));
948
949 if (priv->do_set_bittiming) {
950 /* Finally, set the bit-timing registers */
951 err = priv->do_set_bittiming(dev);
952 if (err)
953 return err;
954 }
955 }
956
957 if (data[IFLA_CAN_CTRLMODE]) {
958 struct can_ctrlmode *cm;
959 u32 ctrlstatic;
960 u32 maskedflags;
961
962 /* Do not allow changing controller mode while running */
963 if (dev->flags & IFF_UP)
964 return -EBUSY;
965 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
966 ctrlstatic = priv->ctrlmode_static;
967 maskedflags = cm->flags & cm->mask;
968
969 /* check whether provided bits are allowed to be passed */
970 if (cm->mask & ~(priv->ctrlmode_supported | ctrlstatic))
971 return -EOPNOTSUPP;
972
973 /* do not check for static fd-non-iso if 'fd' is disabled */
974 if (!(maskedflags & CAN_CTRLMODE_FD))
975 ctrlstatic &= ~CAN_CTRLMODE_FD_NON_ISO;
976
977 /* make sure static options are provided by configuration */
978 if ((maskedflags & ctrlstatic) != ctrlstatic)
979 return -EOPNOTSUPP;
980
981 /* clear bits to be modified and copy the flag values */
982 priv->ctrlmode &= ~cm->mask;
983 priv->ctrlmode |= maskedflags;
984
985 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
986 if (priv->ctrlmode & CAN_CTRLMODE_FD)
987 dev->mtu = CANFD_MTU;
988 else
989 dev->mtu = CAN_MTU;
990 }
991
992 if (data[IFLA_CAN_RESTART_MS]) {
993 /* Do not allow changing restart delay while running */
994 if (dev->flags & IFF_UP)
995 return -EBUSY;
996 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
997 }
998
999 if (data[IFLA_CAN_RESTART]) {
1000 /* Do not allow a restart while not running */
1001 if (!(dev->flags & IFF_UP))
1002 return -EINVAL;
1003 err = can_restart_now(dev);
1004 if (err)
1005 return err;
1006 }
1007
1008 if (data[IFLA_CAN_DATA_BITTIMING]) {
1009 struct can_bittiming dbt;
1010
1011 /* Do not allow changing bittiming while running */
1012 if (dev->flags & IFF_UP)
1013 return -EBUSY;
1014
1015 /* Calculate bittiming parameters based on
1016 * data_bittiming_const if set, otherwise pass bitrate
1017 * directly via do_set_bitrate(). Bail out if neither
1018 * is given.
1019 */
1020 if (!priv->data_bittiming_const && !priv->do_set_data_bittiming)
1021 return -EOPNOTSUPP;
1022
1023 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
1024 sizeof(dbt));
1025 err = can_get_bittiming(dev, &dbt,
1026 priv->data_bittiming_const,
1027 priv->data_bitrate_const,
1028 priv->data_bitrate_const_cnt);
1029 if (err)
1030 return err;
1031
1032 if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
1033 netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
1034 priv->bitrate_max);
1035 return -EINVAL;
1036 }
1037
1038 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
1039
1040 if (priv->do_set_data_bittiming) {
1041 /* Finally, set the bit-timing registers */
1042 err = priv->do_set_data_bittiming(dev);
1043 if (err)
1044 return err;
1045 }
1046 }
1047
1048 if (data[IFLA_CAN_TERMINATION]) {
1049 const u16 termval = nla_get_u16(data[IFLA_CAN_TERMINATION]);
1050 const unsigned int num_term = priv->termination_const_cnt;
1051 unsigned int i;
1052
1053 if (!priv->do_set_termination)
1054 return -EOPNOTSUPP;
1055
1056 /* check whether given value is supported by the interface */
1057 for (i = 0; i < num_term; i++) {
1058 if (termval == priv->termination_const[i])
1059 break;
1060 }
1061 if (i >= num_term)
1062 return -EINVAL;
1063
1064 /* Finally, set the termination value */
1065 err = priv->do_set_termination(dev, termval);
1066 if (err)
1067 return err;
1068
1069 priv->termination = termval;
1070 }
1071
1072 return 0;
1073}
1074
1075static size_t can_get_size(const struct net_device *dev)
1076{
1077 struct can_priv *priv = netdev_priv(dev);
1078 size_t size = 0;
1079
1080 if (priv->bittiming.bitrate) /* IFLA_CAN_BITTIMING */
1081 size += nla_total_size(sizeof(struct can_bittiming));
1082 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
1083 size += nla_total_size(sizeof(struct can_bittiming_const));
1084 size += nla_total_size(sizeof(struct can_clock)); /* IFLA_CAN_CLOCK */
1085 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
1086 size += nla_total_size(sizeof(struct can_ctrlmode)); /* IFLA_CAN_CTRLMODE */
1087 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
1088 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
1089 size += nla_total_size(sizeof(struct can_berr_counter));
1090 if (priv->data_bittiming.bitrate) /* IFLA_CAN_DATA_BITTIMING */
1091 size += nla_total_size(sizeof(struct can_bittiming));
1092 if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */
1093 size += nla_total_size(sizeof(struct can_bittiming_const));
1094 if (priv->termination_const) {
1095 size += nla_total_size(sizeof(priv->termination)); /* IFLA_CAN_TERMINATION */
1096 size += nla_total_size(sizeof(*priv->termination_const) * /* IFLA_CAN_TERMINATION_CONST */
1097 priv->termination_const_cnt);
1098 }
1099 if (priv->bitrate_const) /* IFLA_CAN_BITRATE_CONST */
1100 size += nla_total_size(sizeof(*priv->bitrate_const) *
1101 priv->bitrate_const_cnt);
1102 if (priv->data_bitrate_const) /* IFLA_CAN_DATA_BITRATE_CONST */
1103 size += nla_total_size(sizeof(*priv->data_bitrate_const) *
1104 priv->data_bitrate_const_cnt);
1105 size += sizeof(priv->bitrate_max); /* IFLA_CAN_BITRATE_MAX */
1106
1107 return size;
1108}
1109
1110static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
1111{
1112 struct can_priv *priv = netdev_priv(dev);
1113 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
1114 struct can_berr_counter bec;
1115 enum can_state state = priv->state;
1116
1117 if (priv->do_get_state)
1118 priv->do_get_state(dev, &state);
1119
1120 if ((priv->bittiming.bitrate &&
1121 nla_put(skb, IFLA_CAN_BITTIMING,
1122 sizeof(priv->bittiming), &priv->bittiming)) ||
1123
1124 (priv->bittiming_const &&
1125 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
1126 sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
1127
1128 nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
1129 nla_put_u32(skb, IFLA_CAN_STATE, state) ||
1130 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
1131 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
1132
1133 (priv->do_get_berr_counter &&
1134 !priv->do_get_berr_counter(dev, &bec) &&
1135 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
1136
1137 (priv->data_bittiming.bitrate &&
1138 nla_put(skb, IFLA_CAN_DATA_BITTIMING,
1139 sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
1140
1141 (priv->data_bittiming_const &&
1142 nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
1143 sizeof(*priv->data_bittiming_const),
1144 priv->data_bittiming_const)) ||
1145
1146 (priv->termination_const &&
1147 (nla_put_u16(skb, IFLA_CAN_TERMINATION, priv->termination) ||
1148 nla_put(skb, IFLA_CAN_TERMINATION_CONST,
1149 sizeof(*priv->termination_const) *
1150 priv->termination_const_cnt,
1151 priv->termination_const))) ||
1152
1153 (priv->bitrate_const &&
1154 nla_put(skb, IFLA_CAN_BITRATE_CONST,
1155 sizeof(*priv->bitrate_const) *
1156 priv->bitrate_const_cnt,
1157 priv->bitrate_const)) ||
1158
1159 (priv->data_bitrate_const &&
1160 nla_put(skb, IFLA_CAN_DATA_BITRATE_CONST,
1161 sizeof(*priv->data_bitrate_const) *
1162 priv->data_bitrate_const_cnt,
1163 priv->data_bitrate_const)) ||
1164
1165 (nla_put(skb, IFLA_CAN_BITRATE_MAX,
1166 sizeof(priv->bitrate_max),
1167 &priv->bitrate_max))
1168 )
1169
1170 return -EMSGSIZE;
1171
1172 return 0;
1173}
1174
1175static size_t can_get_xstats_size(const struct net_device *dev)
1176{
1177 return sizeof(struct can_device_stats);
1178}
1179
1180static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
1181{
1182 struct can_priv *priv = netdev_priv(dev);
1183
1184 if (nla_put(skb, IFLA_INFO_XSTATS,
1185 sizeof(priv->can_stats), &priv->can_stats))
1186 goto nla_put_failure;
1187 return 0;
1188
1189nla_put_failure:
1190 return -EMSGSIZE;
1191}
1192
1193static int can_newlink(struct net *src_net, struct net_device *dev,
1194 struct nlattr *tb[], struct nlattr *data[],
1195 struct netlink_ext_ack *extack)
1196{
1197 return -EOPNOTSUPP;
1198}
1199
1200static void can_dellink(struct net_device *dev, struct list_head *head)
1201{
1202 return;
1203}
1204
1205static struct rtnl_link_ops can_link_ops __read_mostly = {
1206 .kind = "can",
1207 .maxtype = IFLA_CAN_MAX,
1208 .policy = can_policy,
1209 .setup = can_setup,
1210 .validate = can_validate,
1211 .newlink = can_newlink,
1212 .changelink = can_changelink,
1213 .dellink = can_dellink,
1214 .get_size = can_get_size,
1215 .fill_info = can_fill_info,
1216 .get_xstats_size = can_get_xstats_size,
1217 .fill_xstats = can_fill_xstats,
1218};
1219
1220/*
1221 * Register the CAN network device
1222 */
1223int register_candev(struct net_device *dev)
1224{
1225 struct can_priv *priv = netdev_priv(dev);
1226
1227 /* Ensure termination_const, termination_const_cnt and
1228 * do_set_termination consistency. All must be either set or
1229 * unset.
1230 */
1231 if ((!priv->termination_const != !priv->termination_const_cnt) ||
1232 (!priv->termination_const != !priv->do_set_termination))
1233 return -EINVAL;
1234
1235 if (!priv->bitrate_const != !priv->bitrate_const_cnt)
1236 return -EINVAL;
1237
1238 if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
1239 return -EINVAL;
1240
1241 dev->rtnl_link_ops = &can_link_ops;
1242 return register_netdev(dev);
1243}
1244EXPORT_SYMBOL_GPL(register_candev);
1245
1246/*
1247 * Unregister the CAN network device
1248 */
1249void unregister_candev(struct net_device *dev)
1250{
1251 unregister_netdev(dev);
1252}
1253EXPORT_SYMBOL_GPL(unregister_candev);
1254
1255/*
1256 * Test if a network device is a candev based device
1257 * and return the can_priv* if so.
1258 */
1259struct can_priv *safe_candev_priv(struct net_device *dev)
1260{
1261 if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1262 return NULL;
1263
1264 return netdev_priv(dev);
1265}
1266EXPORT_SYMBOL_GPL(safe_candev_priv);
1267
1268static __init int can_dev_init(void)
1269{
1270 int err;
1271
1272 can_led_notifier_init();
1273
1274 err = rtnl_link_register(&can_link_ops);
1275 if (!err)
1276 printk(KERN_INFO MOD_DESC "\n");
1277
1278 return err;
1279}
1280module_init(can_dev_init);
1281
1282static __exit void can_dev_exit(void)
1283{
1284 rtnl_link_unregister(&can_link_ops);
1285
1286 can_led_notifier_exit();
1287}
1288module_exit(can_dev_exit);
1289
1290MODULE_ALIAS_RTNL_LINK("can");