1 /*
2  * CAN driver for PEAK System PCAN-USB adapter
3  * Derived from the PCAN project file driver/src/pcan_usb.c
4  *
5  * Copyright (C) 2003-2010 PEAK System-Technik GmbH
6  * Copyright (C) 2011-2012 Stephane Grosjean <s.grosjean@peak-system.com>
7  *
8  * Many thanks to Klaus Hitschler <klaus.hitschler@gmx.de>
9  *
10  * This program is free software; you can redistribute it and/or modify it
11  * under the terms of the GNU General Public License as published
12  * by the Free Software Foundation; version 2 of the License.
13  *
14  * This program is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  * General Public License for more details.
18  */
19 #include <linux/netdevice.h>
20 #include <linux/usb.h>
21 #include <linux/module.h>
22 
23 #include <linux/can.h>
24 #include <linux/can/dev.h>
25 #include <linux/can/error.h>
26 
27 #include "pcan_usb_core.h"
28 
29 MODULE_SUPPORTED_DEVICE("PEAK-System PCAN-USB adapter");
30 
31 /* PCAN-USB Endpoints */
32 #define PCAN_USB_EP_CMDOUT		1
33 #define PCAN_USB_EP_CMDIN		(PCAN_USB_EP_CMDOUT | USB_DIR_IN)
34 #define PCAN_USB_EP_MSGOUT		2
35 #define PCAN_USB_EP_MSGIN		(PCAN_USB_EP_MSGOUT | USB_DIR_IN)
36 
37 /* PCAN-USB command struct */
38 #define PCAN_USB_CMD_FUNC		0
39 #define PCAN_USB_CMD_NUM		1
40 #define PCAN_USB_CMD_ARGS		2
41 #define PCAN_USB_CMD_ARGS_LEN		14
42 #define PCAN_USB_CMD_LEN		(PCAN_USB_CMD_ARGS + \
43 					 PCAN_USB_CMD_ARGS_LEN)
44 
45 /* PCAN-USB command timeout (ms.) */
46 #define PCAN_USB_COMMAND_TIMEOUT	1000
47 
48 /* PCAN-USB startup timeout (ms.) */
49 #define PCAN_USB_STARTUP_TIMEOUT	10
50 
51 /* PCAN-USB rx/tx buffers size */
52 #define PCAN_USB_RX_BUFFER_SIZE		64
53 #define PCAN_USB_TX_BUFFER_SIZE		64
54 
55 #define PCAN_USB_MSG_HEADER_LEN		2
56 
57 /* PCAN-USB adapter internal clock (MHz) */
58 #define PCAN_USB_CRYSTAL_HZ		16000000
59 
60 /* PCAN-USB USB message record status/len field */
61 #define PCAN_USB_STATUSLEN_TIMESTAMP	(1 << 7)
62 #define PCAN_USB_STATUSLEN_INTERNAL	(1 << 6)
63 #define PCAN_USB_STATUSLEN_EXT_ID	(1 << 5)
64 #define PCAN_USB_STATUSLEN_RTR		(1 << 4)
65 #define PCAN_USB_STATUSLEN_DLC		(0xf)
66 
67 /* PCAN-USB error flags */
68 #define PCAN_USB_ERROR_TXFULL		0x01
69 #define PCAN_USB_ERROR_RXQOVR		0x02
70 #define PCAN_USB_ERROR_BUS_LIGHT	0x04
71 #define PCAN_USB_ERROR_BUS_HEAVY	0x08
72 #define PCAN_USB_ERROR_BUS_OFF		0x10
73 #define PCAN_USB_ERROR_RXQEMPTY		0x20
74 #define PCAN_USB_ERROR_QOVR		0x40
75 #define PCAN_USB_ERROR_TXQFULL		0x80
76 
77 /* SJA1000 modes */
78 #define SJA1000_MODE_NORMAL		0x00
79 #define SJA1000_MODE_INIT		0x01
80 
81 /*
82  * tick duration = 42.666 us =>
83  * (tick_number * 44739243) >> 20 ~ (tick_number * 42666) / 1000
84  * accuracy = 10^-7
85  */
86 #define PCAN_USB_TS_DIV_SHIFTER		20
87 #define PCAN_USB_TS_US_PER_TICK		44739243
88 
89 /* PCAN-USB messages record types */
90 #define PCAN_USB_REC_ERROR		1
91 #define PCAN_USB_REC_ANALOG		2
92 #define PCAN_USB_REC_BUSLOAD		3
93 #define PCAN_USB_REC_TS			4
94 #define PCAN_USB_REC_BUSEVT		5
95 
96 /* private to PCAN-USB adapter */
97 struct pcan_usb {
98 	struct peak_usb_device dev;
99 	struct peak_time_ref time_ref;
100 	struct timer_list restart_timer;
101 };
102 
103 /* incoming message context for decoding */
104 struct pcan_usb_msg_context {
105 	u16 ts16;
106 	u8 prev_ts8;
107 	u8 *ptr;
108 	u8 *end;
109 	u8 rec_cnt;
110 	u8 rec_idx;
111 	u8 rec_data_idx;
112 	struct net_device *netdev;
113 	struct pcan_usb *pdev;
114 };
115 
116 /*
117  * send a command
118  */
119 static int pcan_usb_send_cmd(struct peak_usb_device *dev, u8 f, u8 n, u8 *p)
120 {
121 	int err;
122 	int actual_length;
123 
124 	/* usb device unregistered? */
125 	if (!(dev->state & PCAN_USB_STATE_CONNECTED))
126 		return 0;
127 
128 	dev->cmd_buf[PCAN_USB_CMD_FUNC] = f;
129 	dev->cmd_buf[PCAN_USB_CMD_NUM] = n;
130 
131 	if (p)
132 		memcpy(dev->cmd_buf + PCAN_USB_CMD_ARGS,
133 			p, PCAN_USB_CMD_ARGS_LEN);
134 
135 	err = usb_bulk_msg(dev->udev,
136 			usb_sndbulkpipe(dev->udev, PCAN_USB_EP_CMDOUT),
137 			dev->cmd_buf, PCAN_USB_CMD_LEN, &actual_length,
138 			PCAN_USB_COMMAND_TIMEOUT);
139 	if (err)
140 		netdev_err(dev->netdev,
141 			"sending cmd f=0x%x n=0x%x failure: %d\n",
142 			f, n, err);
143 	return err;
144 }
145 
146 /*
147  * send a command then wait for its response
148  */
149 static int pcan_usb_wait_rsp(struct peak_usb_device *dev, u8 f, u8 n, u8 *p)
150 {
151 	int err;
152 	int actual_length;
153 
154 	/* usb device unregistered? */
155 	if (!(dev->state & PCAN_USB_STATE_CONNECTED))
156 		return 0;
157 
158 	/* first, send command */
159 	err = pcan_usb_send_cmd(dev, f, n, NULL);
160 	if (err)
161 		return err;
162 
163 	err = usb_bulk_msg(dev->udev,
164 		usb_rcvbulkpipe(dev->udev, PCAN_USB_EP_CMDIN),
165 		dev->cmd_buf, PCAN_USB_CMD_LEN, &actual_length,
166 		PCAN_USB_COMMAND_TIMEOUT);
167 	if (err)
168 		netdev_err(dev->netdev,
169 			"waiting rsp f=0x%x n=0x%x failure: %d\n", f, n, err);
170 	else if (p)
171 		memcpy(p, dev->cmd_buf + PCAN_USB_CMD_ARGS,
172 			PCAN_USB_CMD_ARGS_LEN);
173 
174 	return err;
175 }
176 
177 static int pcan_usb_set_sja1000(struct peak_usb_device *dev, u8 mode)
178 {
179 	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
180 		[1] = mode,
181 	};
182 
183 	return pcan_usb_send_cmd(dev, 9, 2, args);
184 }
185 
186 static int pcan_usb_set_bus(struct peak_usb_device *dev, u8 onoff)
187 {
188 	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
189 		[0] = !!onoff,
190 	};
191 
192 	return pcan_usb_send_cmd(dev, 3, 2, args);
193 }
194 
195 static int pcan_usb_set_silent(struct peak_usb_device *dev, u8 onoff)
196 {
197 	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
198 		[0] = !!onoff,
199 	};
200 
201 	return pcan_usb_send_cmd(dev, 3, 3, args);
202 }
203 
204 static int pcan_usb_set_ext_vcc(struct peak_usb_device *dev, u8 onoff)
205 {
206 	u8 args[PCAN_USB_CMD_ARGS_LEN] = {
207 		[0] = !!onoff,
208 	};
209 
210 	return pcan_usb_send_cmd(dev, 10, 2, args);
211 }
212 
213 /*
214  * set bittiming value to can
215  */
216 static int pcan_usb_set_bittiming(struct peak_usb_device *dev,
217 				  struct can_bittiming *bt)
218 {
219 	u8 args[PCAN_USB_CMD_ARGS_LEN];
220 	u8 btr0, btr1;
221 
222 	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
223 	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
224 		(((bt->phase_seg2 - 1) & 0x7) << 4);
225 	if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
226 		btr1 |= 0x80;
227 
228 	netdev_info(dev->netdev, "setting BTR0=0x%02x BTR1=0x%02x\n",
229 		btr0, btr1);
230 
231 	args[0] = btr1;
232 	args[1] = btr0;
233 
234 	return pcan_usb_send_cmd(dev, 1, 2, args);
235 }
236 
237 /*
238  * init/reset can
239  */
240 static int pcan_usb_write_mode(struct peak_usb_device *dev, u8 onoff)
241 {
242 	int err;
243 
244 	err = pcan_usb_set_bus(dev, onoff);
245 	if (err)
246 		return err;
247 
248 	if (!onoff) {
249 		err = pcan_usb_set_sja1000(dev, SJA1000_MODE_INIT);
250 	} else {
251 		/* the PCAN-USB needs time to init */
252 		set_current_state(TASK_INTERRUPTIBLE);
253 		schedule_timeout(msecs_to_jiffies(PCAN_USB_STARTUP_TIMEOUT));
254 	}
255 
256 	return err;
257 }
258 
259 /*
260  * handle end of waiting for the device to reset
261  */
262 static void pcan_usb_restart(struct timer_list *t)
263 {
264 	struct pcan_usb *pdev = from_timer(pdev, t, restart_timer);
265 	struct peak_usb_device *dev = &pdev->dev;
266 
267 	/* notify candev and netdev */
268 	peak_usb_restart_complete(dev);
269 }
270 
271 /*
272  * handle the submission of the restart urb
273  */
274 static void pcan_usb_restart_pending(struct urb *urb)
275 {
276 	struct pcan_usb *pdev = urb->context;
277 
278 	/* the PCAN-USB needs time to restart */
279 	mod_timer(&pdev->restart_timer,
280 			jiffies + msecs_to_jiffies(PCAN_USB_STARTUP_TIMEOUT));
281 
282 	/* can delete usb resources */
283 	peak_usb_async_complete(urb);
284 }
285 
286 /*
287  * handle asynchronous restart
288  */
289 static int pcan_usb_restart_async(struct peak_usb_device *dev, struct urb *urb,
290 				  u8 *buf)
291 {
292 	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
293 
294 	if (timer_pending(&pdev->restart_timer))
295 		return -EBUSY;
296 
297 	/* set bus on */
298 	buf[PCAN_USB_CMD_FUNC] = 3;
299 	buf[PCAN_USB_CMD_NUM] = 2;
300 	buf[PCAN_USB_CMD_ARGS] = 1;
301 
302 	usb_fill_bulk_urb(urb, dev->udev,
303 			usb_sndbulkpipe(dev->udev, PCAN_USB_EP_CMDOUT),
304 			buf, PCAN_USB_CMD_LEN,
305 			pcan_usb_restart_pending, pdev);
306 
307 	return usb_submit_urb(urb, GFP_ATOMIC);
308 }
309 
310 /*
311  * read serial number from device
312  */
313 static int pcan_usb_get_serial(struct peak_usb_device *dev, u32 *serial_number)
314 {
315 	u8 args[PCAN_USB_CMD_ARGS_LEN];
316 	int err;
317 
318 	err = pcan_usb_wait_rsp(dev, 6, 1, args);
319 	if (err) {
320 		netdev_err(dev->netdev, "getting serial failure: %d\n", err);
321 	} else if (serial_number) {
322 		__le32 tmp32;
323 
324 		memcpy(&tmp32, args, 4);
325 		*serial_number = le32_to_cpu(tmp32);
326 	}
327 
328 	return err;
329 }
330 
331 /*
332  * read device id from device
333  */
334 static int pcan_usb_get_device_id(struct peak_usb_device *dev, u32 *device_id)
335 {
336 	u8 args[PCAN_USB_CMD_ARGS_LEN];
337 	int err;
338 
339 	err = pcan_usb_wait_rsp(dev, 4, 1, args);
340 	if (err)
341 		netdev_err(dev->netdev, "getting device id failure: %d\n", err);
342 	else if (device_id)
343 		*device_id = args[0];
344 
345 	return err;
346 }
347 
348 /*
349  * update current time ref with received timestamp
350  */
351 static int pcan_usb_update_ts(struct pcan_usb_msg_context *mc)
352 {
353 	__le16 tmp16;
354 
355 	if ((mc->ptr+2) > mc->end)
356 		return -EINVAL;
357 
358 	memcpy(&tmp16, mc->ptr, 2);
359 
360 	mc->ts16 = le16_to_cpu(tmp16);
361 
362 	if (mc->rec_idx > 0)
363 		peak_usb_update_ts_now(&mc->pdev->time_ref, mc->ts16);
364 	else
365 		peak_usb_set_ts_now(&mc->pdev->time_ref, mc->ts16);
366 
367 	return 0;
368 }
369 
370 /*
371  * decode received timestamp
372  */
373 static int pcan_usb_decode_ts(struct pcan_usb_msg_context *mc, u8 first_packet)
374 {
375 	/* only 1st packet supplies a word timestamp */
376 	if (first_packet) {
377 		__le16 tmp16;
378 
379 		if ((mc->ptr + 2) > mc->end)
380 			return -EINVAL;
381 
382 		memcpy(&tmp16, mc->ptr, 2);
383 		mc->ptr += 2;
384 
385 		mc->ts16 = le16_to_cpu(tmp16);
386 		mc->prev_ts8 = mc->ts16 & 0x00ff;
387 	} else {
388 		u8 ts8;
389 
390 		if ((mc->ptr + 1) > mc->end)
391 			return -EINVAL;
392 
393 		ts8 = *mc->ptr++;
394 
395 		if (ts8 < mc->prev_ts8)
396 			mc->ts16 += 0x100;
397 
398 		mc->ts16 &= 0xff00;
399 		mc->ts16 |= ts8;
400 		mc->prev_ts8 = ts8;
401 	}
402 
403 	return 0;
404 }
405 
406 static int pcan_usb_decode_error(struct pcan_usb_msg_context *mc, u8 n,
407 				 u8 status_len)
408 {
409 	struct sk_buff *skb;
410 	struct can_frame *cf;
411 	struct timeval tv;
412 	enum can_state new_state;
413 
414 	/* ignore this error until 1st ts received */
415 	if (n == PCAN_USB_ERROR_QOVR)
416 		if (!mc->pdev->time_ref.tick_count)
417 			return 0;
418 
419 	new_state = mc->pdev->dev.can.state;
420 
421 	switch (mc->pdev->dev.can.state) {
422 	case CAN_STATE_ERROR_ACTIVE:
423 		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
424 			new_state = CAN_STATE_ERROR_WARNING;
425 			break;
426 		}
427 
428 	case CAN_STATE_ERROR_WARNING:
429 		if (n & PCAN_USB_ERROR_BUS_HEAVY) {
430 			new_state = CAN_STATE_ERROR_PASSIVE;
431 			break;
432 		}
433 		if (n & PCAN_USB_ERROR_BUS_OFF) {
434 			new_state = CAN_STATE_BUS_OFF;
435 			break;
436 		}
437 		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
438 			/*
439 			 * trick to bypass next comparison and process other
440 			 * errors
441 			 */
442 			new_state = CAN_STATE_MAX;
443 			break;
444 		}
445 		if ((n & PCAN_USB_ERROR_BUS_LIGHT) == 0) {
446 			/* no error (back to active state) */
447 			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
448 			return 0;
449 		}
450 		break;
451 
452 	case CAN_STATE_ERROR_PASSIVE:
453 		if (n & PCAN_USB_ERROR_BUS_OFF) {
454 			new_state = CAN_STATE_BUS_OFF;
455 			break;
456 		}
457 		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
458 			new_state = CAN_STATE_ERROR_WARNING;
459 			break;
460 		}
461 		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
462 			/*
463 			 * trick to bypass next comparison and process other
464 			 * errors
465 			 */
466 			new_state = CAN_STATE_MAX;
467 			break;
468 		}
469 
470 		if ((n & PCAN_USB_ERROR_BUS_HEAVY) == 0) {
471 			/* no error (back to active state) */
472 			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
473 			return 0;
474 		}
475 		break;
476 
477 	default:
478 		/* do nothing waiting for restart */
479 		return 0;
480 	}
481 
482 	/* donot post any error if current state didn't change */
483 	if (mc->pdev->dev.can.state == new_state)
484 		return 0;
485 
486 	/* allocate an skb to store the error frame */
487 	skb = alloc_can_err_skb(mc->netdev, &cf);
488 	if (!skb)
489 		return -ENOMEM;
490 
491 	switch (new_state) {
492 	case CAN_STATE_BUS_OFF:
493 		cf->can_id |= CAN_ERR_BUSOFF;
494 		mc->pdev->dev.can.can_stats.bus_off++;
495 		can_bus_off(mc->netdev);
496 		break;
497 
498 	case CAN_STATE_ERROR_PASSIVE:
499 		cf->can_id |= CAN_ERR_CRTL;
500 		cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE |
501 			       CAN_ERR_CRTL_RX_PASSIVE;
502 		mc->pdev->dev.can.can_stats.error_passive++;
503 		break;
504 
505 	case CAN_STATE_ERROR_WARNING:
506 		cf->can_id |= CAN_ERR_CRTL;
507 		cf->data[1] |= CAN_ERR_CRTL_TX_WARNING |
508 			       CAN_ERR_CRTL_RX_WARNING;
509 		mc->pdev->dev.can.can_stats.error_warning++;
510 		break;
511 
512 	default:
513 		/* CAN_STATE_MAX (trick to handle other errors) */
514 		cf->can_id |= CAN_ERR_CRTL;
515 		cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
516 		mc->netdev->stats.rx_over_errors++;
517 		mc->netdev->stats.rx_errors++;
518 
519 		new_state = mc->pdev->dev.can.state;
520 		break;
521 	}
522 
523 	mc->pdev->dev.can.state = new_state;
524 
525 	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
526 		struct skb_shared_hwtstamps *hwts = skb_hwtstamps(skb);
527 
528 		peak_usb_get_ts_tv(&mc->pdev->time_ref, mc->ts16, &tv);
529 		hwts->hwtstamp = timeval_to_ktime(tv);
530 	}
531 
532 	mc->netdev->stats.rx_packets++;
533 	mc->netdev->stats.rx_bytes += cf->can_dlc;
534 	netif_rx(skb);
535 
536 	return 0;
537 }
538 
539 /*
540  * decode non-data usb message
541  */
542 static int pcan_usb_decode_status(struct pcan_usb_msg_context *mc,
543 				  u8 status_len)
544 {
545 	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
546 	u8 f, n;
547 	int err;
548 
549 	/* check whether function and number can be read */
550 	if ((mc->ptr + 2) > mc->end)
551 		return -EINVAL;
552 
553 	f = mc->ptr[PCAN_USB_CMD_FUNC];
554 	n = mc->ptr[PCAN_USB_CMD_NUM];
555 	mc->ptr += PCAN_USB_CMD_ARGS;
556 
557 	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
558 		int err = pcan_usb_decode_ts(mc, !mc->rec_idx);
559 
560 		if (err)
561 			return err;
562 	}
563 
564 	switch (f) {
565 	case PCAN_USB_REC_ERROR:
566 		err = pcan_usb_decode_error(mc, n, status_len);
567 		if (err)
568 			return err;
569 		break;
570 
571 	case PCAN_USB_REC_ANALOG:
572 		/* analog values (ignored) */
573 		rec_len = 2;
574 		break;
575 
576 	case PCAN_USB_REC_BUSLOAD:
577 		/* bus load (ignored) */
578 		rec_len = 1;
579 		break;
580 
581 	case PCAN_USB_REC_TS:
582 		/* only timestamp */
583 		if (pcan_usb_update_ts(mc))
584 			return -EINVAL;
585 		break;
586 
587 	case PCAN_USB_REC_BUSEVT:
588 		/* error frame/bus event */
589 		if (n & PCAN_USB_ERROR_TXQFULL)
590 			netdev_dbg(mc->netdev, "device Tx queue full)\n");
591 		break;
592 	default:
593 		netdev_err(mc->netdev, "unexpected function %u\n", f);
594 		break;
595 	}
596 
597 	if ((mc->ptr + rec_len) > mc->end)
598 		return -EINVAL;
599 
600 	mc->ptr += rec_len;
601 
602 	return 0;
603 }
604 
605 /*
606  * decode data usb message
607  */
608 static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
609 {
610 	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
611 	struct sk_buff *skb;
612 	struct can_frame *cf;
613 	struct timeval tv;
614 	struct skb_shared_hwtstamps *hwts;
615 
616 	skb = alloc_can_skb(mc->netdev, &cf);
617 	if (!skb)
618 		return -ENOMEM;
619 
620 	if (status_len & PCAN_USB_STATUSLEN_EXT_ID) {
621 		__le32 tmp32;
622 
623 		if ((mc->ptr + 4) > mc->end)
624 			goto decode_failed;
625 
626 		memcpy(&tmp32, mc->ptr, 4);
627 		mc->ptr += 4;
628 
629 		cf->can_id = (le32_to_cpu(tmp32) >> 3) | CAN_EFF_FLAG;
630 	} else {
631 		__le16 tmp16;
632 
633 		if ((mc->ptr + 2) > mc->end)
634 			goto decode_failed;
635 
636 		memcpy(&tmp16, mc->ptr, 2);
637 		mc->ptr += 2;
638 
639 		cf->can_id = le16_to_cpu(tmp16) >> 5;
640 	}
641 
642 	cf->can_dlc = get_can_dlc(rec_len);
643 
644 	/* first data packet timestamp is a word */
645 	if (pcan_usb_decode_ts(mc, !mc->rec_data_idx))
646 		goto decode_failed;
647 
648 	/* read data */
649 	memset(cf->data, 0x0, sizeof(cf->data));
650 	if (status_len & PCAN_USB_STATUSLEN_RTR) {
651 		cf->can_id |= CAN_RTR_FLAG;
652 	} else {
653 		if ((mc->ptr + rec_len) > mc->end)
654 			goto decode_failed;
655 
656 		memcpy(cf->data, mc->ptr, cf->can_dlc);
657 		mc->ptr += rec_len;
658 	}
659 
660 	/* convert timestamp into kernel time */
661 	peak_usb_get_ts_tv(&mc->pdev->time_ref, mc->ts16, &tv);
662 	hwts = skb_hwtstamps(skb);
663 	hwts->hwtstamp = timeval_to_ktime(tv);
664 
665 	/* update statistics */
666 	mc->netdev->stats.rx_packets++;
667 	mc->netdev->stats.rx_bytes += cf->can_dlc;
668 	/* push the skb */
669 	netif_rx(skb);
670 
671 	return 0;
672 
673 decode_failed:
674 	dev_kfree_skb(skb);
675 	return -EINVAL;
676 }
677 
678 /*
679  * process incoming message
680  */
681 static int pcan_usb_decode_msg(struct peak_usb_device *dev, u8 *ibuf, u32 lbuf)
682 {
683 	struct pcan_usb_msg_context mc = {
684 		.rec_cnt = ibuf[1],
685 		.ptr = ibuf + PCAN_USB_MSG_HEADER_LEN,
686 		.end = ibuf + lbuf,
687 		.netdev = dev->netdev,
688 		.pdev = container_of(dev, struct pcan_usb, dev),
689 	};
690 	int err;
691 
692 	for (err = 0; mc.rec_idx < mc.rec_cnt && !err; mc.rec_idx++) {
693 		u8 sl = *mc.ptr++;
694 
695 		/* handle status and error frames here */
696 		if (sl & PCAN_USB_STATUSLEN_INTERNAL) {
697 			err = pcan_usb_decode_status(&mc, sl);
698 		/* handle normal can frames here */
699 		} else {
700 			err = pcan_usb_decode_data(&mc, sl);
701 			mc.rec_data_idx++;
702 		}
703 	}
704 
705 	return err;
706 }
707 
708 /*
709  * process any incoming buffer
710  */
711 static int pcan_usb_decode_buf(struct peak_usb_device *dev, struct urb *urb)
712 {
713 	int err = 0;
714 
715 	if (urb->actual_length > PCAN_USB_MSG_HEADER_LEN) {
716 		err = pcan_usb_decode_msg(dev, urb->transfer_buffer,
717 			urb->actual_length);
718 
719 	} else if (urb->actual_length > 0) {
720 		netdev_err(dev->netdev, "usb message length error (%u)\n",
721 			urb->actual_length);
722 		err = -EINVAL;
723 	}
724 
725 	return err;
726 }
727 
728 /*
729  * process outgoing packet
730  */
731 static int pcan_usb_encode_msg(struct peak_usb_device *dev, struct sk_buff *skb,
732 			       u8 *obuf, size_t *size)
733 {
734 	struct net_device *netdev = dev->netdev;
735 	struct net_device_stats *stats = &netdev->stats;
736 	struct can_frame *cf = (struct can_frame *)skb->data;
737 	u8 *pc;
738 
739 	obuf[0] = 2;
740 	obuf[1] = 1;
741 
742 	pc = obuf + PCAN_USB_MSG_HEADER_LEN;
743 
744 	/* status/len byte */
745 	*pc = cf->can_dlc;
746 	if (cf->can_id & CAN_RTR_FLAG)
747 		*pc |= PCAN_USB_STATUSLEN_RTR;
748 
749 	/* can id */
750 	if (cf->can_id & CAN_EFF_FLAG) {
751 		__le32 tmp32 = cpu_to_le32((cf->can_id & CAN_ERR_MASK) << 3);
752 
753 		*pc |= PCAN_USB_STATUSLEN_EXT_ID;
754 		memcpy(++pc, &tmp32, 4);
755 		pc += 4;
756 	} else {
757 		__le16 tmp16 = cpu_to_le16((cf->can_id & CAN_ERR_MASK) << 5);
758 
759 		memcpy(++pc, &tmp16, 2);
760 		pc += 2;
761 	}
762 
763 	/* can data */
764 	if (!(cf->can_id & CAN_RTR_FLAG)) {
765 		memcpy(pc, cf->data, cf->can_dlc);
766 		pc += cf->can_dlc;
767 	}
768 
769 	obuf[(*size)-1] = (u8)(stats->tx_packets & 0xff);
770 
771 	return 0;
772 }
773 
774 /*
775  * start interface
776  */
777 static int pcan_usb_start(struct peak_usb_device *dev)
778 {
779 	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
780 
781 	/* number of bits used in timestamps read from adapter struct */
782 	peak_usb_init_time_ref(&pdev->time_ref, &pcan_usb);
783 
784 	/* if revision greater than 3, can put silent mode on/off */
785 	if (dev->device_rev > 3) {
786 		int err;
787 
788 		err = pcan_usb_set_silent(dev,
789 				dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY);
790 		if (err)
791 			return err;
792 	}
793 
794 	return pcan_usb_set_ext_vcc(dev, 0);
795 }
796 
797 static int pcan_usb_init(struct peak_usb_device *dev)
798 {
799 	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
800 	u32 serial_number;
801 	int err;
802 
803 	/* initialize a timer needed to wait for hardware restart */
804 	timer_setup(&pdev->restart_timer, pcan_usb_restart, 0);
805 
806 	/*
807 	 * explicit use of dev_xxx() instead of netdev_xxx() here:
808 	 * information displayed are related to the device itself, not
809 	 * to the canx netdevice.
810 	 */
811 	err = pcan_usb_get_serial(dev, &serial_number);
812 	if (err) {
813 		dev_err(dev->netdev->dev.parent,
814 			"unable to read %s serial number (err %d)\n",
815 			pcan_usb.name, err);
816 		return err;
817 	}
818 
819 	dev_info(dev->netdev->dev.parent,
820 		 "PEAK-System %s adapter hwrev %u serial %08X (%u channel)\n",
821 		 pcan_usb.name, dev->device_rev, serial_number,
822 		 pcan_usb.ctrl_count);
823 
824 	return 0;
825 }
826 
827 /*
828  * probe function for new PCAN-USB usb interface
829  */
830 static int pcan_usb_probe(struct usb_interface *intf)
831 {
832 	struct usb_host_interface *if_desc;
833 	int i;
834 
835 	if_desc = intf->altsetting;
836 
837 	/* check interface endpoint addresses */
838 	for (i = 0; i < if_desc->desc.bNumEndpoints; i++) {
839 		struct usb_endpoint_descriptor *ep = &if_desc->endpoint[i].desc;
840 
841 		switch (ep->bEndpointAddress) {
842 		case PCAN_USB_EP_CMDOUT:
843 		case PCAN_USB_EP_CMDIN:
844 		case PCAN_USB_EP_MSGOUT:
845 		case PCAN_USB_EP_MSGIN:
846 			break;
847 		default:
848 			return -ENODEV;
849 		}
850 	}
851 
852 	return 0;
853 }
854 
855 /*
856  * describe the PCAN-USB adapter
857  */
858 static const struct can_bittiming_const pcan_usb_const = {
859 	.name = "pcan_usb",
860 	.tseg1_min = 1,
861 	.tseg1_max = 16,
862 	.tseg2_min = 1,
863 	.tseg2_max = 8,
864 	.sjw_max = 4,
865 	.brp_min = 1,
866 	.brp_max = 64,
867 	.brp_inc = 1,
868 };
869 
870 const struct peak_usb_adapter pcan_usb = {
871 	.name = "PCAN-USB",
872 	.device_id = PCAN_USB_PRODUCT_ID,
873 	.ctrl_count = 1,
874 	.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
875 	.clock = {
876 		.freq = PCAN_USB_CRYSTAL_HZ / 2 ,
877 	},
878 	.bittiming_const = &pcan_usb_const,
879 
880 	/* size of device private data */
881 	.sizeof_dev_private = sizeof(struct pcan_usb),
882 
883 	/* timestamps usage */
884 	.ts_used_bits = 16,
885 	.ts_period = 24575, /* calibration period in ts. */
886 	.us_per_ts_scale = PCAN_USB_TS_US_PER_TICK, /* us=(ts*scale) */
887 	.us_per_ts_shift = PCAN_USB_TS_DIV_SHIFTER, /*  >> shift     */
888 
889 	/* give here messages in/out endpoints */
890 	.ep_msg_in = PCAN_USB_EP_MSGIN,
891 	.ep_msg_out = {PCAN_USB_EP_MSGOUT},
892 
893 	/* size of rx/tx usb buffers */
894 	.rx_buffer_size = PCAN_USB_RX_BUFFER_SIZE,
895 	.tx_buffer_size = PCAN_USB_TX_BUFFER_SIZE,
896 
897 	/* device callbacks */
898 	.intf_probe = pcan_usb_probe,
899 	.dev_init = pcan_usb_init,
900 	.dev_set_bus = pcan_usb_write_mode,
901 	.dev_set_bittiming = pcan_usb_set_bittiming,
902 	.dev_get_device_id = pcan_usb_get_device_id,
903 	.dev_decode_buf = pcan_usb_decode_buf,
904 	.dev_encode_msg = pcan_usb_encode_msg,
905 	.dev_start = pcan_usb_start,
906 	.dev_restart_async = pcan_usb_restart_async,
907 };
908