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drivers: Kill now superfluous ->last_rx stores
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / net / can / dev.c
CommitLineData
39549eef
WG		 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/netdevice.h>
23#include <linux/if_arp.h>
24#include <linux/can.h>
25#include <linux/can/dev.h>
26#include <linux/can/netlink.h>
27#include <net/rtnetlink.h>
28
29#define MOD_DESC "CAN device driver interface"
30
31MODULE_DESCRIPTION(MOD_DESC);
32MODULE_LICENSE("GPL v2");
33MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
34
35#ifdef CONFIG_CAN_CALC_BITTIMING
36#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
37
38/*
39 * Bit-timing calculation derived from:
40 *
41 * Code based on LinCAN sources and H8S2638 project
42 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
43 * Copyright 2005 Stanislav Marek
44 * email: pisa@cmp.felk.cvut.cz
45 *
46 * Calculates proper bit-timing parameters for a specified bit-rate
47 * and sample-point, which can then be used to set the bit-timing
48 * registers of the CAN controller. You can find more information
49 * in the header file linux/can/netlink.h.
50 */
51static int can_update_spt(const struct can_bittiming_const *btc,
52 int sampl_pt, int tseg, int *tseg1, int *tseg2)
53{
54 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
55 if (*tseg2 < btc->tseg2_min)
56 *tseg2 = btc->tseg2_min;
57 if (*tseg2 > btc->tseg2_max)
58 *tseg2 = btc->tseg2_max;
59 *tseg1 = tseg - *tseg2;
60 if (*tseg1 > btc->tseg1_max) {
61 *tseg1 = btc->tseg1_max;
62 *tseg2 = tseg - *tseg1;
63 }
64 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
65}
66
67static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
68{
69 struct can_priv *priv = netdev_priv(dev);
70 const struct can_bittiming_const *btc = priv->bittiming_const;
71 long rate, best_rate = 0;
72 long best_error = 1000000000, error = 0;
73 int best_tseg = 0, best_brp = 0, brp = 0;
74 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
75 int spt_error = 1000, spt = 0, sampl_pt;
76 u64 v64;
77
78 if (!priv->bittiming_const)
79 return -ENOTSUPP;
80
81 /* Use CIA recommended sample points */
82 if (bt->sample_point) {
83 sampl_pt = bt->sample_point;
84 } else {
85 if (bt->bitrate > 800000)
86 sampl_pt = 750;
87 else if (bt->bitrate > 500000)
88 sampl_pt = 800;
89 else
90 sampl_pt = 875;
91 }
92
93 /* tseg even = round down, odd = round up */
94 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
95 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
96 tsegall = 1 + tseg / 2;
97 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
98 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
99 /* chose brp step which is possible in system */
100 brp = (brp / btc->brp_inc) * btc->brp_inc;
101 if ((brp < btc->brp_min) || (brp > btc->brp_max))
102 continue;
103 rate = priv->clock.freq / (brp * tsegall);
104 error = bt->bitrate - rate;
105 /* tseg brp biterror */
106 if (error < 0)
107 error = -error;
108 if (error > best_error)
109 continue;
110 best_error = error;
111 if (error == 0) {
112 spt = can_update_spt(btc, sampl_pt, tseg / 2,
113 &tseg1, &tseg2);
114 error = sampl_pt - spt;
115 if (error < 0)
116 error = -error;
117 if (error > spt_error)
118 continue;
119 spt_error = error;
120 }
121 best_tseg = tseg / 2;
122 best_brp = brp;
123 best_rate = rate;
124 if (error == 0)
125 break;
126 }
127
128 if (best_error) {
129 /* Error in one-tenth of a percent */
130 error = (best_error * 1000) / bt->bitrate;
131 if (error > CAN_CALC_MAX_ERROR) {
132 dev_err(dev->dev.parent,
133 "bitrate error %ld.%ld%% too high\n",
134 error / 10, error % 10);
135 return -EDOM;
136 } else {
137 dev_warn(dev->dev.parent, "bitrate error %ld.%ld%%\n",
138 error / 10, error % 10);
139 }
140 }
141
142 /* real sample point */
143 bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
144 &tseg1, &tseg2);
145
146 v64 = (u64)best_brp * 1000000000UL;
147 do_div(v64, priv->clock.freq);
148 bt->tq = (u32)v64;
149 bt->prop_seg = tseg1 / 2;
150 bt->phase_seg1 = tseg1 - bt->prop_seg;
151 bt->phase_seg2 = tseg2;
152 bt->sjw = 1;
153 bt->brp = best_brp;
154 /* real bit-rate */
155 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
156
157 return 0;
158}
159#else /* !CONFIG_CAN_CALC_BITTIMING */
160static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
161{
162 dev_err(dev->dev.parent, "bit-timing calculation not available\n");
163 return -EINVAL;
164}
165#endif /* CONFIG_CAN_CALC_BITTIMING */
166
167/*
168 * Checks the validity of the specified bit-timing parameters prop_seg,
169 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
170 * prescaler value brp. You can find more information in the header
171 * file linux/can/netlink.h.
172 */
173static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
174{
175 struct can_priv *priv = netdev_priv(dev);
176 const struct can_bittiming_const *btc = priv->bittiming_const;
177 int tseg1, alltseg;
178 u64 brp64;
179
180 if (!priv->bittiming_const)
181 return -ENOTSUPP;
182
183 tseg1 = bt->prop_seg + bt->phase_seg1;
184 if (!bt->sjw)
185 bt->sjw = 1;
186 if (bt->sjw > btc->sjw_max ||
187 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
188 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
189 return -ERANGE;
190
191 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
192 if (btc->brp_inc > 1)
193 do_div(brp64, btc->brp_inc);
194 brp64 += 500000000UL - 1;
195 do_div(brp64, 1000000000UL); /* the practicable BRP */
196 if (btc->brp_inc > 1)
197 brp64 *= btc->brp_inc;
198 bt->brp = (u32)brp64;
199
200 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
201 return -EINVAL;
202
203 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
204 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
205 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
206
207 return 0;
208}
209
210int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
211{
212 struct can_priv *priv = netdev_priv(dev);
213 int err;
214
215 /* Check if the CAN device has bit-timing parameters */
216 if (priv->bittiming_const) {
217
218 /* Non-expert mode? Check if the bitrate has been pre-defined */
219 if (!bt->tq)
220 /* Determine bit-timing parameters */
221 err = can_calc_bittiming(dev, bt);
222 else
223 /* Check bit-timing params and calculate proper brp */
224 err = can_fixup_bittiming(dev, bt);
225 if (err)
226 return err;
227 }
228
229 return 0;
230}
231
232/*
233 * Local echo of CAN messages
234 *
235 * CAN network devices *should* support a local echo functionality
236 * (see Documentation/networking/can.txt). To test the handling of CAN
237 * interfaces that do not support the local echo both driver types are
238 * implemented. In the case that the driver does not support the echo
239 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
240 * to perform the echo as a fallback solution.
241 */
242static void can_flush_echo_skb(struct net_device *dev)
243{
244 struct can_priv *priv = netdev_priv(dev);
245 struct net_device_stats *stats = &dev->stats;
246 int i;
247
248 for (i = 0; i < CAN_ECHO_SKB_MAX; i++) {
249 if (priv->echo_skb[i]) {
250 kfree_skb(priv->echo_skb[i]);
251 priv->echo_skb[i] = NULL;
252 stats->tx_dropped++;
253 stats->tx_aborted_errors++;
254 }
255 }
256}
257
258/*
259 * Put the skb on the stack to be looped backed locally lateron
260 *
261 * The function is typically called in the start_xmit function
262 * of the device driver. The driver must protect access to
263 * priv->echo_skb, if necessary.
264 */
265void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx)
266{
267 struct can_priv *priv = netdev_priv(dev);
268
269 /* check flag whether this packet has to be looped back */
270 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
271 kfree_skb(skb);
272 return;
273 }
274
275 if (!priv->echo_skb[idx]) {
276 struct sock *srcsk = skb->sk;
277
278 if (atomic_read(&skb->users) != 1) {
279 struct sk_buff *old_skb = skb;
280
281 skb = skb_clone(old_skb, GFP_ATOMIC);
282 kfree_skb(old_skb);
283 if (!skb)
284 return;
285 } else
286 skb_orphan(skb);
287
288 skb->sk = srcsk;
289
290 /* make settings for echo to reduce code in irq context */
291 skb->protocol = htons(ETH_P_CAN);
292 skb->pkt_type = PACKET_BROADCAST;
293 skb->ip_summed = CHECKSUM_UNNECESSARY;
294 skb->dev = dev;
295
296 /* save this skb for tx interrupt echo handling */
297 priv->echo_skb[idx] = skb;
298 } else {
299 /* locking problem with netif_stop_queue() ?? */
300 dev_err(dev->dev.parent, "%s: BUG! echo_skb is occupied!\n",
301 __func__);
302 kfree_skb(skb);
303 }
304}
305EXPORT_SYMBOL_GPL(can_put_echo_skb);
306
307/*
308 * Get the skb from the stack and loop it back locally
309 *
310 * The function is typically called when the TX done interrupt
311 * is handled in the device driver. The driver must protect
312 * access to priv->echo_skb, if necessary.
313 */
314void can_get_echo_skb(struct net_device *dev, int idx)
315{
316 struct can_priv *priv = netdev_priv(dev);
317
318 if ((dev->flags & IFF_ECHO) && priv->echo_skb[idx]) {
319 netif_rx(priv->echo_skb[idx]);
320 priv->echo_skb[idx] = NULL;
321 }
322}
323EXPORT_SYMBOL_GPL(can_get_echo_skb);
324
325/*
326 * CAN device restart for bus-off recovery
327 */
328void can_restart(unsigned long data)
329{
330 struct net_device *dev = (struct net_device *)data;
331 struct can_priv *priv = netdev_priv(dev);
332 struct net_device_stats *stats = &dev->stats;
333 struct sk_buff *skb;
334 struct can_frame *cf;
335 int err;
336
337 BUG_ON(netif_carrier_ok(dev));
338
339 /*
340 * No synchronization needed because the device is bus-off and
341 * no messages can come in or go out.
342 */
343 can_flush_echo_skb(dev);
344
345 /* send restart message upstream */
346 skb = dev_alloc_skb(sizeof(struct can_frame));
347 if (skb == NULL) {
348 err = -ENOMEM;
b3d0df7c 349 goto restart;
39549eef
WG		 350 }
351 skb->dev = dev;
352 skb->protocol = htons(ETH_P_CAN);
353 cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
354 memset(cf, 0, sizeof(struct can_frame));
355 cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
356 cf->can_dlc = CAN_ERR_DLC;
357
358 netif_rx(skb);
359
39549eef
WG		 360 stats->rx_packets++;
361 stats->rx_bytes += cf->can_dlc;
362
b3d0df7c 363restart:
39549eef
WG		 364 dev_dbg(dev->dev.parent, "restarted\n");
365 priv->can_stats.restarts++;
366
367 /* Now restart the device */
368 err = priv->do_set_mode(dev, CAN_MODE_START);
369
39549eef
WG		 370 netif_carrier_on(dev);
371 if (err)
372 dev_err(dev->dev.parent, "Error %d during restart", err);
373}
374
375int can_restart_now(struct net_device *dev)
376{
377 struct can_priv *priv = netdev_priv(dev);
378
379 /*
380 * A manual restart is only permitted if automatic restart is
381 * disabled and the device is in the bus-off state
382 */
383 if (priv->restart_ms)
384 return -EINVAL;
385 if (priv->state != CAN_STATE_BUS_OFF)
386 return -EBUSY;
387
388 /* Runs as soon as possible in the timer context */
389 mod_timer(&priv->restart_timer, jiffies);
390
391 return 0;
392}
393
394/*
395 * CAN bus-off
396 *
397 * This functions should be called when the device goes bus-off to
398 * tell the netif layer that no more packets can be sent or received.
399 * If enabled, a timer is started to trigger bus-off recovery.
400 */
401void can_bus_off(struct net_device *dev)
402{
403 struct can_priv *priv = netdev_priv(dev);
404
405 dev_dbg(dev->dev.parent, "bus-off\n");
406
407 netif_carrier_off(dev);
408 priv->can_stats.bus_off++;
409
410 if (priv->restart_ms)
411 mod_timer(&priv->restart_timer,
412 jiffies + (priv->restart_ms * HZ) / 1000);
413}
414EXPORT_SYMBOL_GPL(can_bus_off);
415
416static void can_setup(struct net_device *dev)
417{
418 dev->type = ARPHRD_CAN;
419 dev->mtu = sizeof(struct can_frame);
420 dev->hard_header_len = 0;
421 dev->addr_len = 0;
422 dev->tx_queue_len = 10;
423
424 /* New-style flags. */
425 dev->flags = IFF_NOARP;
426 dev->features = NETIF_F_NO_CSUM;
427}
428
429/*
430 * Allocate and setup space for the CAN network device
431 */
432struct net_device *alloc_candev(int sizeof_priv)
433{
434 struct net_device *dev;
435 struct can_priv *priv;
436
437 dev = alloc_netdev(sizeof_priv, "can%d", can_setup);
438 if (!dev)
439 return NULL;
440
441 priv = netdev_priv(dev);
442
443 priv->state = CAN_STATE_STOPPED;
444
445 init_timer(&priv->restart_timer);
446
447 return dev;
448}
449EXPORT_SYMBOL_GPL(alloc_candev);
450
451/*
452 * Free space of the CAN network device
453 */
454void free_candev(struct net_device *dev)
455{
456 free_netdev(dev);
457}
458EXPORT_SYMBOL_GPL(free_candev);
459
460/*
461 * Common open function when the device gets opened.
462 *
463 * This function should be called in the open function of the device
464 * driver.
465 */
466int open_candev(struct net_device *dev)
467{
468 struct can_priv *priv = netdev_priv(dev);
469
470 if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
471 dev_err(dev->dev.parent, "bit-timing not yet defined\n");
472 return -EINVAL;
473 }
474
1b0d9224
WG		 475 /* Switch carrier on if device was stopped while in bus-off state */
476 if (!netif_carrier_ok(dev))
477 netif_carrier_on(dev);
478
39549eef
WG		 479 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
480
481 return 0;
482}
128ced8f 483EXPORT_SYMBOL_GPL(open_candev);
39549eef
WG		 484
485/*
486 * Common close function for cleanup before the device gets closed.
487 *
488 * This function should be called in the close function of the device
489 * driver.
490 */
491void close_candev(struct net_device *dev)
492{
493 struct can_priv *priv = netdev_priv(dev);
494
495 if (del_timer_sync(&priv->restart_timer))
496 dev_put(dev);
497 can_flush_echo_skb(dev);
498}
499EXPORT_SYMBOL_GPL(close_candev);
500
501/*
502 * CAN netlink interface
503 */
504static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
505 [IFLA_CAN_STATE] = { .type = NLA_U32 },
506 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
507 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
508 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
509 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
510 [IFLA_CAN_BITTIMING_CONST]
511 = { .len = sizeof(struct can_bittiming_const) },
512 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
513};
514
515static int can_changelink(struct net_device *dev,
516 struct nlattr *tb[], struct nlattr *data[])
517{
518 struct can_priv *priv = netdev_priv(dev);
519 int err;
520
521 /* We need synchronization with dev->stop() */
522 ASSERT_RTNL();
523
524 if (data[IFLA_CAN_CTRLMODE]) {
525 struct can_ctrlmode *cm;
526
527 /* Do not allow changing controller mode while running */
528 if (dev->flags & IFF_UP)
529 return -EBUSY;
530 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
531 priv->ctrlmode &= ~cm->mask;
532 priv->ctrlmode |= cm->flags;
533 }
534
535 if (data[IFLA_CAN_BITTIMING]) {
536 struct can_bittiming bt;
537
538 /* Do not allow changing bittiming while running */
539 if (dev->flags & IFF_UP)
540 return -EBUSY;
541 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
542 if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
543 return -EINVAL;
544 err = can_get_bittiming(dev, &bt);
545 if (err)
546 return err;
547 memcpy(&priv->bittiming, &bt, sizeof(bt));
548
549 if (priv->do_set_bittiming) {
550 /* Finally, set the bit-timing registers */
551 err = priv->do_set_bittiming(dev);
552 if (err)
553 return err;
554 }
555 }
556
557 if (data[IFLA_CAN_RESTART_MS]) {
558 /* Do not allow changing restart delay while running */
559 if (dev->flags & IFF_UP)
560 return -EBUSY;
561 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
562 }
563
564 if (data[IFLA_CAN_RESTART]) {
565 /* Do not allow a restart while not running */
566 if (!(dev->flags & IFF_UP))
567 return -EINVAL;
568 err = can_restart_now(dev);
569 if (err)
570 return err;
571 }
572
573 return 0;
574}
575
576static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
577{
578 struct can_priv *priv = netdev_priv(dev);
579 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
580 enum can_state state = priv->state;
581
582 if (priv->do_get_state)
583 priv->do_get_state(dev, &state);
584 NLA_PUT_U32(skb, IFLA_CAN_STATE, state);
585 NLA_PUT(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm);
586 NLA_PUT_U32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms);
587 NLA_PUT(skb, IFLA_CAN_BITTIMING,
588 sizeof(priv->bittiming), &priv->bittiming);
589 NLA_PUT(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock);
590 if (priv->bittiming_const)
591 NLA_PUT(skb, IFLA_CAN_BITTIMING_CONST,
592 sizeof(*priv->bittiming_const), priv->bittiming_const);
593
594 return 0;
595
596nla_put_failure:
597 return -EMSGSIZE;
598}
599
600static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
601{
602 struct can_priv *priv = netdev_priv(dev);
603
604 NLA_PUT(skb, IFLA_INFO_XSTATS,
605 sizeof(priv->can_stats), &priv->can_stats);
606
607 return 0;
608
609nla_put_failure:
610 return -EMSGSIZE;
611}
612
993e6f2f
OH		 613static int can_newlink(struct net_device *dev,
614 struct nlattr *tb[], struct nlattr *data[])
615{
616 return -EOPNOTSUPP;
617}
618
39549eef
WG		 619static struct rtnl_link_ops can_link_ops __read_mostly = {
620 .kind = "can",
621 .maxtype = IFLA_CAN_MAX,
622 .policy = can_policy,
623 .setup = can_setup,
993e6f2f 624 .newlink = can_newlink,
39549eef
WG		 625 .changelink = can_changelink,
626 .fill_info = can_fill_info,
627 .fill_xstats = can_fill_xstats,
628};
629
630/*
631 * Register the CAN network device
632 */
633int register_candev(struct net_device *dev)
634{
635 dev->rtnl_link_ops = &can_link_ops;
636 return register_netdev(dev);
637}
638EXPORT_SYMBOL_GPL(register_candev);
639
640/*
641 * Unregister the CAN network device
642 */
643void unregister_candev(struct net_device *dev)
644{
645 unregister_netdev(dev);
646}
647EXPORT_SYMBOL_GPL(unregister_candev);
648
649static __init int can_dev_init(void)
650{
651 int err;
652
653 err = rtnl_link_register(&can_link_ops);
654 if (!err)
655 printk(KERN_INFO MOD_DESC "\n");
656
657 return err;
658}
659module_init(can_dev_init);
660
661static __exit void can_dev_exit(void)
662{
663 rtnl_link_unregister(&can_link_ops);
664}
665module_exit(can_dev_exit);
666
667MODULE_ALIAS_RTNL_LINK("can");
kernel source for telekom puls (alcatel/mediatek)