1// SPDX-License-Identifier: GPL-2.0-only
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
7#include <linux/kernel.h>
8#include <linux/slab.h>
9#include <linux/netdevice.h>
10#include <linux/if_arp.h>
11#include <linux/workqueue.h>
12#include <linux/can.h>
13#include <linux/can/can-ml.h>
14#include <linux/can/dev.h>
15#include <linux/can/skb.h>
16#include <linux/gpio/consumer.h>
17#include <linux/of.h>
18
19static void can_update_state_error_stats(struct net_device *dev,
20 enum can_state new_state)
21{
22 struct can_priv *priv = netdev_priv(dev);
23
24 if (new_state <= priv->state)
25 return;
26
27 switch (new_state) {
28 case CAN_STATE_ERROR_WARNING:
29 priv->can_stats.error_warning++;
30 break;
31 case CAN_STATE_ERROR_PASSIVE:
32 priv->can_stats.error_passive++;
33 break;
34 case CAN_STATE_BUS_OFF:
35 priv->can_stats.bus_off++;
36 break;
37 default:
38 break;
39 }
40}
41
42static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
43{
44 switch (state) {
45 case CAN_STATE_ERROR_ACTIVE:
46 return CAN_ERR_CRTL_ACTIVE;
47 case CAN_STATE_ERROR_WARNING:
48 return CAN_ERR_CRTL_TX_WARNING;
49 case CAN_STATE_ERROR_PASSIVE:
50 return CAN_ERR_CRTL_TX_PASSIVE;
51 default:
52 return 0;
53 }
54}
55
56static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
57{
58 switch (state) {
59 case CAN_STATE_ERROR_ACTIVE:
60 return CAN_ERR_CRTL_ACTIVE;
61 case CAN_STATE_ERROR_WARNING:
62 return CAN_ERR_CRTL_RX_WARNING;
63 case CAN_STATE_ERROR_PASSIVE:
64 return CAN_ERR_CRTL_RX_PASSIVE;
65 default:
66 return 0;
67 }
68}
69
70const char *can_get_state_str(const enum can_state state)
71{
72 switch (state) {
73 case CAN_STATE_ERROR_ACTIVE:
74 return "Error Active";
75 case CAN_STATE_ERROR_WARNING:
76 return "Error Warning";
77 case CAN_STATE_ERROR_PASSIVE:
78 return "Error Passive";
79 case CAN_STATE_BUS_OFF:
80 return "Bus Off";
81 case CAN_STATE_STOPPED:
82 return "Stopped";
83 case CAN_STATE_SLEEPING:
84 return "Sleeping";
85 default:
86 return "<unknown>";
87 }
88
89 return "<unknown>";
90}
91EXPORT_SYMBOL_GPL(can_get_state_str);
92
93static enum can_state can_state_err_to_state(u16 err)
94{
95 if (err < CAN_ERROR_WARNING_THRESHOLD)
96 return CAN_STATE_ERROR_ACTIVE;
97 if (err < CAN_ERROR_PASSIVE_THRESHOLD)
98 return CAN_STATE_ERROR_WARNING;
99 if (err < CAN_BUS_OFF_THRESHOLD)
100 return CAN_STATE_ERROR_PASSIVE;
101
102 return CAN_STATE_BUS_OFF;
103}
104
105void can_state_get_by_berr_counter(const struct net_device *dev,
106 const struct can_berr_counter *bec,
107 enum can_state *tx_state,
108 enum can_state *rx_state)
109{
110 *tx_state = can_state_err_to_state(err: bec->txerr);
111 *rx_state = can_state_err_to_state(err: bec->rxerr);
112}
113EXPORT_SYMBOL_GPL(can_state_get_by_berr_counter);
114
115void can_change_state(struct net_device *dev, struct can_frame *cf,
116 enum can_state tx_state, enum can_state rx_state)
117{
118 struct can_priv *priv = netdev_priv(dev);
119 enum can_state new_state = max(tx_state, rx_state);
120
121 if (unlikely(new_state == priv->state)) {
122 netdev_warn(dev, format: "%s: oops, state did not change", __func__);
123 return;
124 }
125
126 netdev_dbg(dev, "Controller changed from %s State (%d) into %s State (%d).\n",
127 can_get_state_str(priv->state), priv->state,
128 can_get_state_str(new_state), new_state);
129
130 can_update_state_error_stats(dev, new_state);
131 priv->state = new_state;
132
133 if (!cf)
134 return;
135
136 if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
137 cf->can_id |= CAN_ERR_BUSOFF;
138 return;
139 }
140
141 cf->can_id |= CAN_ERR_CRTL;
142 cf->data[1] |= tx_state >= rx_state ?
143 can_tx_state_to_frame(dev, state: tx_state) : 0;
144 cf->data[1] |= tx_state <= rx_state ?
145 can_rx_state_to_frame(dev, state: rx_state) : 0;
146}
147EXPORT_SYMBOL_GPL(can_change_state);
148
149/* CAN device restart for bus-off recovery */
150static void can_restart(struct net_device *dev)
151{
152 struct can_priv *priv = netdev_priv(dev);
153 struct sk_buff *skb;
154 struct can_frame *cf;
155 int err;
156
157 if (netif_carrier_ok(dev))
158 netdev_err(dev, format: "Attempt to restart for bus-off recovery, but carrier is OK?\n");
159
160 /* No synchronization needed because the device is bus-off and
161 * no messages can come in or go out.
162 */
163 can_flush_echo_skb(dev);
164
165 /* send restart message upstream */
166 skb = alloc_can_err_skb(dev, cf: &cf);
167 if (skb) {
168 cf->can_id |= CAN_ERR_RESTARTED;
169 netif_rx(skb);
170 }
171
172 /* Now restart the device */
173 netif_carrier_on(dev);
174 err = priv->do_set_mode(dev, CAN_MODE_START);
175 if (err) {
176 netdev_err(dev, format: "Restart failed, error %pe\n", ERR_PTR(error: err));
177 netif_carrier_off(dev);
178 } else {
179 netdev_dbg(dev, "Restarted\n");
180 priv->can_stats.restarts++;
181 }
182}
183
184static void can_restart_work(struct work_struct *work)
185{
186 struct delayed_work *dwork = to_delayed_work(work);
187 struct can_priv *priv = container_of(dwork, struct can_priv,
188 restart_work);
189
190 can_restart(dev: priv->dev);
191}
192
193int can_restart_now(struct net_device *dev)
194{
195 struct can_priv *priv = netdev_priv(dev);
196
197 /* A manual restart is only permitted if automatic restart is
198 * disabled and the device is in the bus-off state
199 */
200 if (priv->restart_ms)
201 return -EINVAL;
202 if (priv->state != CAN_STATE_BUS_OFF)
203 return -EBUSY;
204
205 cancel_delayed_work_sync(dwork: &priv->restart_work);
206 can_restart(dev);
207
208 return 0;
209}
210
211/* CAN bus-off
212 *
213 * This functions should be called when the device goes bus-off to
214 * tell the netif layer that no more packets can be sent or received.
215 * If enabled, a timer is started to trigger bus-off recovery.
216 */
217void can_bus_off(struct net_device *dev)
218{
219 struct can_priv *priv = netdev_priv(dev);
220
221 if (priv->restart_ms)
222 netdev_info(dev, format: "bus-off, scheduling restart in %d ms\n",
223 priv->restart_ms);
224 else
225 netdev_info(dev, format: "bus-off\n");
226
227 netif_carrier_off(dev);
228
229 if (priv->restart_ms)
230 schedule_delayed_work(dwork: &priv->restart_work,
231 delay: msecs_to_jiffies(m: priv->restart_ms));
232}
233EXPORT_SYMBOL_GPL(can_bus_off);
234
235void can_setup(struct net_device *dev)
236{
237 dev->type = ARPHRD_CAN;
238 dev->mtu = CAN_MTU;
239 dev->hard_header_len = 0;
240 dev->addr_len = 0;
241 dev->tx_queue_len = 10;
242
243 /* New-style flags. */
244 dev->flags = IFF_NOARP;
245 dev->features = NETIF_F_HW_CSUM;
246}
247
248/* Allocate and setup space for the CAN network device */
249struct net_device *alloc_candev_mqs(int sizeof_priv, unsigned int echo_skb_max,
250 unsigned int txqs, unsigned int rxqs)
251{
252 struct can_ml_priv *can_ml;
253 struct net_device *dev;
254 struct can_priv *priv;
255 int size;
256
257 /* We put the driver's priv, the CAN mid layer priv and the
258 * echo skb into the netdevice's priv. The memory layout for
259 * the netdev_priv is like this:
260 *
261 * +-------------------------+
262 * | driver's priv |
263 * +-------------------------+
264 * | struct can_ml_priv |
265 * +-------------------------+
266 * | array of struct sk_buff |
267 * +-------------------------+
268 */
269
270 size = ALIGN(sizeof_priv, NETDEV_ALIGN) + sizeof(struct can_ml_priv);
271
272 if (echo_skb_max)
273 size = ALIGN(size, sizeof(struct sk_buff *)) +
274 echo_skb_max * sizeof(struct sk_buff *);
275
276 dev = alloc_netdev_mqs(sizeof_priv: size, name: "can%d", NET_NAME_UNKNOWN, setup: can_setup,
277 txqs, rxqs);
278 if (!dev)
279 return NULL;
280
281 priv = netdev_priv(dev);
282 priv->dev = dev;
283
284 can_ml = (void *)priv + ALIGN(sizeof_priv, NETDEV_ALIGN);
285 can_set_ml_priv(dev, ml_priv: can_ml);
286
287 if (echo_skb_max) {
288 priv->echo_skb_max = echo_skb_max;
289 priv->echo_skb = (void *)priv +
290 (size - echo_skb_max * sizeof(struct sk_buff *));
291 }
292
293 priv->state = CAN_STATE_STOPPED;
294
295 INIT_DELAYED_WORK(&priv->restart_work, can_restart_work);
296
297 return dev;
298}
299EXPORT_SYMBOL_GPL(alloc_candev_mqs);
300
301/* Free space of the CAN network device */
302void free_candev(struct net_device *dev)
303{
304 free_netdev(dev);
305}
306EXPORT_SYMBOL_GPL(free_candev);
307
308/* changing MTU and control mode for CAN/CANFD devices */
309int can_change_mtu(struct net_device *dev, int new_mtu)
310{
311 struct can_priv *priv = netdev_priv(dev);
312 u32 ctrlmode_static = can_get_static_ctrlmode(priv);
313
314 /* Do not allow changing the MTU while running */
315 if (dev->flags & IFF_UP)
316 return -EBUSY;
317
318 /* allow change of MTU according to the CANFD ability of the device */
319 switch (new_mtu) {
320 case CAN_MTU:
321 /* 'CANFD-only' controllers can not switch to CAN_MTU */
322 if (ctrlmode_static & CAN_CTRLMODE_FD)
323 return -EINVAL;
324
325 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
326 break;
327
328 case CANFD_MTU:
329 /* check for potential CANFD ability */
330 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD) &&
331 !(ctrlmode_static & CAN_CTRLMODE_FD))
332 return -EINVAL;
333
334 priv->ctrlmode |= CAN_CTRLMODE_FD;
335 break;
336
337 default:
338 return -EINVAL;
339 }
340
341 dev->mtu = new_mtu;
342 return 0;
343}
344EXPORT_SYMBOL_GPL(can_change_mtu);
345
346/* generic implementation of netdev_ops::ndo_eth_ioctl for CAN devices
347 * supporting hardware timestamps
348 */
349int can_eth_ioctl_hwts(struct net_device *netdev, struct ifreq *ifr, int cmd)
350{
351 struct hwtstamp_config hwts_cfg = { 0 };
352
353 switch (cmd) {
354 case SIOCSHWTSTAMP: /* set */
355 if (copy_from_user(to: &hwts_cfg, from: ifr->ifr_data, n: sizeof(hwts_cfg)))
356 return -EFAULT;
357 if (hwts_cfg.tx_type == HWTSTAMP_TX_ON &&
358 hwts_cfg.rx_filter == HWTSTAMP_FILTER_ALL)
359 return 0;
360 return -ERANGE;
361
362 case SIOCGHWTSTAMP: /* get */
363 hwts_cfg.tx_type = HWTSTAMP_TX_ON;
364 hwts_cfg.rx_filter = HWTSTAMP_FILTER_ALL;
365 if (copy_to_user(to: ifr->ifr_data, from: &hwts_cfg, n: sizeof(hwts_cfg)))
366 return -EFAULT;
367 return 0;
368
369 default:
370 return -EOPNOTSUPP;
371 }
372}
373EXPORT_SYMBOL(can_eth_ioctl_hwts);
374
375/* generic implementation of ethtool_ops::get_ts_info for CAN devices
376 * supporting hardware timestamps
377 */
378int can_ethtool_op_get_ts_info_hwts(struct net_device *dev,
379 struct ethtool_ts_info *info)
380{
381 info->so_timestamping =
382 SOF_TIMESTAMPING_TX_SOFTWARE |
383 SOF_TIMESTAMPING_RX_SOFTWARE |
384 SOF_TIMESTAMPING_SOFTWARE |
385 SOF_TIMESTAMPING_TX_HARDWARE |
386 SOF_TIMESTAMPING_RX_HARDWARE |
387 SOF_TIMESTAMPING_RAW_HARDWARE;
388 info->phc_index = -1;
389 info->tx_types = BIT(HWTSTAMP_TX_ON);
390 info->rx_filters = BIT(HWTSTAMP_FILTER_ALL);
391
392 return 0;
393}
394EXPORT_SYMBOL(can_ethtool_op_get_ts_info_hwts);
395
396/* Common open function when the device gets opened.
397 *
398 * This function should be called in the open function of the device
399 * driver.
400 */
401int open_candev(struct net_device *dev)
402{
403 struct can_priv *priv = netdev_priv(dev);
404
405 if (!priv->bittiming.bitrate) {
406 netdev_err(dev, format: "bit-timing not yet defined\n");
407 return -EINVAL;
408 }
409
410 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
411 if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
412 (!priv->data_bittiming.bitrate ||
413 priv->data_bittiming.bitrate < priv->bittiming.bitrate)) {
414 netdev_err(dev, format: "incorrect/missing data bit-timing\n");
415 return -EINVAL;
416 }
417
418 /* Switch carrier on if device was stopped while in bus-off state */
419 if (!netif_carrier_ok(dev))
420 netif_carrier_on(dev);
421
422 return 0;
423}
424EXPORT_SYMBOL_GPL(open_candev);
425
426#ifdef CONFIG_OF
427/* Common function that can be used to understand the limitation of
428 * a transceiver when it provides no means to determine these limitations
429 * at runtime.
430 */
431void of_can_transceiver(struct net_device *dev)
432{
433 struct device_node *dn;
434 struct can_priv *priv = netdev_priv(dev);
435 struct device_node *np = dev->dev.parent->of_node;
436 int ret;
437
438 dn = of_get_child_by_name(node: np, name: "can-transceiver");
439 if (!dn)
440 return;
441
442 ret = of_property_read_u32(np: dn, propname: "max-bitrate", out_value: &priv->bitrate_max);
443 of_node_put(node: dn);
444 if ((ret && ret != -EINVAL) || (!ret && !priv->bitrate_max))
445 netdev_warn(dev, format: "Invalid value for transceiver max bitrate. Ignoring bitrate limit.\n");
446}
447EXPORT_SYMBOL_GPL(of_can_transceiver);
448#endif
449
450/* Common close function for cleanup before the device gets closed.
451 *
452 * This function should be called in the close function of the device
453 * driver.
454 */
455void close_candev(struct net_device *dev)
456{
457 struct can_priv *priv = netdev_priv(dev);
458
459 cancel_delayed_work_sync(dwork: &priv->restart_work);
460 can_flush_echo_skb(dev);
461}
462EXPORT_SYMBOL_GPL(close_candev);
463
464static int can_set_termination(struct net_device *ndev, u16 term)
465{
466 struct can_priv *priv = netdev_priv(dev: ndev);
467 int set;
468
469 if (term == priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED])
470 set = 1;
471 else
472 set = 0;
473
474 gpiod_set_value(desc: priv->termination_gpio, value: set);
475
476 return 0;
477}
478
479static int can_get_termination(struct net_device *ndev)
480{
481 struct can_priv *priv = netdev_priv(dev: ndev);
482 struct device *dev = ndev->dev.parent;
483 struct gpio_desc *gpio;
484 u32 term;
485 int ret;
486
487 /* Disabling termination by default is the safe choice: Else if many
488 * bus participants enable it, no communication is possible at all.
489 */
490 gpio = devm_gpiod_get_optional(dev, con_id: "termination", flags: GPIOD_OUT_LOW);
491 if (IS_ERR(ptr: gpio))
492 return dev_err_probe(dev, err: PTR_ERR(ptr: gpio),
493 fmt: "Cannot get termination-gpios\n");
494
495 if (!gpio)
496 return 0;
497
498 ret = device_property_read_u32(dev, propname: "termination-ohms", val: &term);
499 if (ret) {
500 netdev_err(dev: ndev, format: "Cannot get termination-ohms: %pe\n",
501 ERR_PTR(error: ret));
502 return ret;
503 }
504
505 if (term > U16_MAX) {
506 netdev_err(dev: ndev, format: "Invalid termination-ohms value (%u > %u)\n",
507 term, U16_MAX);
508 return -EINVAL;
509 }
510
511 priv->termination_const_cnt = ARRAY_SIZE(priv->termination_gpio_ohms);
512 priv->termination_const = priv->termination_gpio_ohms;
513 priv->termination_gpio = gpio;
514 priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_DISABLED] =
515 CAN_TERMINATION_DISABLED;
516 priv->termination_gpio_ohms[CAN_TERMINATION_GPIO_ENABLED] = term;
517 priv->do_set_termination = can_set_termination;
518
519 return 0;
520}
521
522static bool
523can_bittiming_const_valid(const struct can_bittiming_const *btc)
524{
525 if (!btc)
526 return true;
527
528 if (!btc->sjw_max)
529 return false;
530
531 return true;
532}
533
534/* Register the CAN network device */
535int register_candev(struct net_device *dev)
536{
537 struct can_priv *priv = netdev_priv(dev);
538 int err;
539
540 /* Ensure termination_const, termination_const_cnt and
541 * do_set_termination consistency. All must be either set or
542 * unset.
543 */
544 if ((!priv->termination_const != !priv->termination_const_cnt) ||
545 (!priv->termination_const != !priv->do_set_termination))
546 return -EINVAL;
547
548 if (!priv->bitrate_const != !priv->bitrate_const_cnt)
549 return -EINVAL;
550
551 if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
552 return -EINVAL;
553
554 /* We only support either fixed bit rates or bit timing const. */
555 if ((priv->bitrate_const || priv->data_bitrate_const) &&
556 (priv->bittiming_const || priv->data_bittiming_const))
557 return -EINVAL;
558
559 if (!can_bittiming_const_valid(btc: priv->bittiming_const) ||
560 !can_bittiming_const_valid(btc: priv->data_bittiming_const))
561 return -EINVAL;
562
563 if (!priv->termination_const) {
564 err = can_get_termination(ndev: dev);
565 if (err)
566 return err;
567 }
568
569 dev->rtnl_link_ops = &can_link_ops;
570 netif_carrier_off(dev);
571
572 return register_netdev(dev);
573}
574EXPORT_SYMBOL_GPL(register_candev);
575
576/* Unregister the CAN network device */
577void unregister_candev(struct net_device *dev)
578{
579 unregister_netdev(dev);
580}
581EXPORT_SYMBOL_GPL(unregister_candev);
582
583/* Test if a network device is a candev based device
584 * and return the can_priv* if so.
585 */
586struct can_priv *safe_candev_priv(struct net_device *dev)
587{
588 if (dev->type != ARPHRD_CAN || dev->rtnl_link_ops != &can_link_ops)
589 return NULL;
590
591 return netdev_priv(dev);
592}
593EXPORT_SYMBOL_GPL(safe_candev_priv);
594
595static __init int can_dev_init(void)
596{
597 int err;
598
599 err = can_netlink_register();
600 if (!err)
601 pr_info("CAN device driver interface\n");
602
603 return err;
604}
605module_init(can_dev_init);
606
607static __exit void can_dev_exit(void)
608{
609 can_netlink_unregister();
610}
611module_exit(can_dev_exit);
612
613MODULE_ALIAS_RTNL_LINK("can");
614

source code of linux/drivers/net/can/dev/dev.c