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