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 	enum can_state new_state;
412 
413 	/* ignore this error until 1st ts received */
414 	if (n == PCAN_USB_ERROR_QOVR)
415 		if (!mc->pdev->time_ref.tick_count)
416 			return 0;
417 
418 	new_state = mc->pdev->dev.can.state;
419 
420 	switch (mc->pdev->dev.can.state) {
421 	case CAN_STATE_ERROR_ACTIVE:
422 		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
423 			new_state = CAN_STATE_ERROR_WARNING;
424 			break;
425 		}
426 
427 	case CAN_STATE_ERROR_WARNING:
428 		if (n & PCAN_USB_ERROR_BUS_HEAVY) {
429 			new_state = CAN_STATE_ERROR_PASSIVE;
430 			break;
431 		}
432 		if (n & PCAN_USB_ERROR_BUS_OFF) {
433 			new_state = CAN_STATE_BUS_OFF;
434 			break;
435 		}
436 		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
437 			/*
438 			 * trick to bypass next comparison and process other
439 			 * errors
440 			 */
441 			new_state = CAN_STATE_MAX;
442 			break;
443 		}
444 		if ((n & PCAN_USB_ERROR_BUS_LIGHT) == 0) {
445 			/* no error (back to active state) */
446 			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
447 			return 0;
448 		}
449 		break;
450 
451 	case CAN_STATE_ERROR_PASSIVE:
452 		if (n & PCAN_USB_ERROR_BUS_OFF) {
453 			new_state = CAN_STATE_BUS_OFF;
454 			break;
455 		}
456 		if (n & PCAN_USB_ERROR_BUS_LIGHT) {
457 			new_state = CAN_STATE_ERROR_WARNING;
458 			break;
459 		}
460 		if (n & (PCAN_USB_ERROR_RXQOVR | PCAN_USB_ERROR_QOVR)) {
461 			/*
462 			 * trick to bypass next comparison and process other
463 			 * errors
464 			 */
465 			new_state = CAN_STATE_MAX;
466 			break;
467 		}
468 
469 		if ((n & PCAN_USB_ERROR_BUS_HEAVY) == 0) {
470 			/* no error (back to active state) */
471 			mc->pdev->dev.can.state = CAN_STATE_ERROR_ACTIVE;
472 			return 0;
473 		}
474 		break;
475 
476 	default:
477 		/* do nothing waiting for restart */
478 		return 0;
479 	}
480 
481 	/* donot post any error if current state didn't change */
482 	if (mc->pdev->dev.can.state == new_state)
483 		return 0;
484 
485 	/* allocate an skb to store the error frame */
486 	skb = alloc_can_err_skb(mc->netdev, &cf);
487 	if (!skb)
488 		return -ENOMEM;
489 
490 	switch (new_state) {
491 	case CAN_STATE_BUS_OFF:
492 		cf->can_id |= CAN_ERR_BUSOFF;
493 		mc->pdev->dev.can.can_stats.bus_off++;
494 		can_bus_off(mc->netdev);
495 		break;
496 
497 	case CAN_STATE_ERROR_PASSIVE:
498 		cf->can_id |= CAN_ERR_CRTL;
499 		cf->data[1] |= CAN_ERR_CRTL_TX_PASSIVE |
500 			       CAN_ERR_CRTL_RX_PASSIVE;
501 		mc->pdev->dev.can.can_stats.error_passive++;
502 		break;
503 
504 	case CAN_STATE_ERROR_WARNING:
505 		cf->can_id |= CAN_ERR_CRTL;
506 		cf->data[1] |= CAN_ERR_CRTL_TX_WARNING |
507 			       CAN_ERR_CRTL_RX_WARNING;
508 		mc->pdev->dev.can.can_stats.error_warning++;
509 		break;
510 
511 	default:
512 		/* CAN_STATE_MAX (trick to handle other errors) */
513 		cf->can_id |= CAN_ERR_CRTL;
514 		cf->data[1] |= CAN_ERR_CRTL_RX_OVERFLOW;
515 		mc->netdev->stats.rx_over_errors++;
516 		mc->netdev->stats.rx_errors++;
517 
518 		new_state = mc->pdev->dev.can.state;
519 		break;
520 	}
521 
522 	mc->pdev->dev.can.state = new_state;
523 
524 	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
525 		struct skb_shared_hwtstamps *hwts = skb_hwtstamps(skb);
526 
527 		peak_usb_get_ts_time(&mc->pdev->time_ref, mc->ts16,
528 				     &hwts->hwtstamp);
529 	}
530 
531 	mc->netdev->stats.rx_packets++;
532 	mc->netdev->stats.rx_bytes += cf->can_dlc;
533 	netif_rx(skb);
534 
535 	return 0;
536 }
537 
538 /*
539  * decode non-data usb message
540  */
541 static int pcan_usb_decode_status(struct pcan_usb_msg_context *mc,
542 				  u8 status_len)
543 {
544 	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
545 	u8 f, n;
546 	int err;
547 
548 	/* check whether function and number can be read */
549 	if ((mc->ptr + 2) > mc->end)
550 		return -EINVAL;
551 
552 	f = mc->ptr[PCAN_USB_CMD_FUNC];
553 	n = mc->ptr[PCAN_USB_CMD_NUM];
554 	mc->ptr += PCAN_USB_CMD_ARGS;
555 
556 	if (status_len & PCAN_USB_STATUSLEN_TIMESTAMP) {
557 		int err = pcan_usb_decode_ts(mc, !mc->rec_idx);
558 
559 		if (err)
560 			return err;
561 	}
562 
563 	switch (f) {
564 	case PCAN_USB_REC_ERROR:
565 		err = pcan_usb_decode_error(mc, n, status_len);
566 		if (err)
567 			return err;
568 		break;
569 
570 	case PCAN_USB_REC_ANALOG:
571 		/* analog values (ignored) */
572 		rec_len = 2;
573 		break;
574 
575 	case PCAN_USB_REC_BUSLOAD:
576 		/* bus load (ignored) */
577 		rec_len = 1;
578 		break;
579 
580 	case PCAN_USB_REC_TS:
581 		/* only timestamp */
582 		if (pcan_usb_update_ts(mc))
583 			return -EINVAL;
584 		break;
585 
586 	case PCAN_USB_REC_BUSEVT:
587 		/* error frame/bus event */
588 		if (n & PCAN_USB_ERROR_TXQFULL)
589 			netdev_dbg(mc->netdev, "device Tx queue full)\n");
590 		break;
591 	default:
592 		netdev_err(mc->netdev, "unexpected function %u\n", f);
593 		break;
594 	}
595 
596 	if ((mc->ptr + rec_len) > mc->end)
597 		return -EINVAL;
598 
599 	mc->ptr += rec_len;
600 
601 	return 0;
602 }
603 
604 /*
605  * decode data usb message
606  */
607 static int pcan_usb_decode_data(struct pcan_usb_msg_context *mc, u8 status_len)
608 {
609 	u8 rec_len = status_len & PCAN_USB_STATUSLEN_DLC;
610 	struct sk_buff *skb;
611 	struct can_frame *cf;
612 	struct skb_shared_hwtstamps *hwts;
613 
614 	skb = alloc_can_skb(mc->netdev, &cf);
615 	if (!skb)
616 		return -ENOMEM;
617 
618 	if (status_len & PCAN_USB_STATUSLEN_EXT_ID) {
619 		__le32 tmp32;
620 
621 		if ((mc->ptr + 4) > mc->end)
622 			goto decode_failed;
623 
624 		memcpy(&tmp32, mc->ptr, 4);
625 		mc->ptr += 4;
626 
627 		cf->can_id = (le32_to_cpu(tmp32) >> 3) | CAN_EFF_FLAG;
628 	} else {
629 		__le16 tmp16;
630 
631 		if ((mc->ptr + 2) > mc->end)
632 			goto decode_failed;
633 
634 		memcpy(&tmp16, mc->ptr, 2);
635 		mc->ptr += 2;
636 
637 		cf->can_id = le16_to_cpu(tmp16) >> 5;
638 	}
639 
640 	cf->can_dlc = get_can_dlc(rec_len);
641 
642 	/* first data packet timestamp is a word */
643 	if (pcan_usb_decode_ts(mc, !mc->rec_data_idx))
644 		goto decode_failed;
645 
646 	/* read data */
647 	memset(cf->data, 0x0, sizeof(cf->data));
648 	if (status_len & PCAN_USB_STATUSLEN_RTR) {
649 		cf->can_id |= CAN_RTR_FLAG;
650 	} else {
651 		if ((mc->ptr + rec_len) > mc->end)
652 			goto decode_failed;
653 
654 		memcpy(cf->data, mc->ptr, cf->can_dlc);
655 		mc->ptr += rec_len;
656 	}
657 
658 	/* convert timestamp into kernel time */
659 	hwts = skb_hwtstamps(skb);
660 	peak_usb_get_ts_time(&mc->pdev->time_ref, mc->ts16, &hwts->hwtstamp);
661 
662 	/* update statistics */
663 	mc->netdev->stats.rx_packets++;
664 	mc->netdev->stats.rx_bytes += cf->can_dlc;
665 	/* push the skb */
666 	netif_rx(skb);
667 
668 	return 0;
669 
670 decode_failed:
671 	dev_kfree_skb(skb);
672 	return -EINVAL;
673 }
674 
675 /*
676  * process incoming message
677  */
678 static int pcan_usb_decode_msg(struct peak_usb_device *dev, u8 *ibuf, u32 lbuf)
679 {
680 	struct pcan_usb_msg_context mc = {
681 		.rec_cnt = ibuf[1],
682 		.ptr = ibuf + PCAN_USB_MSG_HEADER_LEN,
683 		.end = ibuf + lbuf,
684 		.netdev = dev->netdev,
685 		.pdev = container_of(dev, struct pcan_usb, dev),
686 	};
687 	int err;
688 
689 	for (err = 0; mc.rec_idx < mc.rec_cnt && !err; mc.rec_idx++) {
690 		u8 sl = *mc.ptr++;
691 
692 		/* handle status and error frames here */
693 		if (sl & PCAN_USB_STATUSLEN_INTERNAL) {
694 			err = pcan_usb_decode_status(&mc, sl);
695 		/* handle normal can frames here */
696 		} else {
697 			err = pcan_usb_decode_data(&mc, sl);
698 			mc.rec_data_idx++;
699 		}
700 	}
701 
702 	return err;
703 }
704 
705 /*
706  * process any incoming buffer
707  */
708 static int pcan_usb_decode_buf(struct peak_usb_device *dev, struct urb *urb)
709 {
710 	int err = 0;
711 
712 	if (urb->actual_length > PCAN_USB_MSG_HEADER_LEN) {
713 		err = pcan_usb_decode_msg(dev, urb->transfer_buffer,
714 			urb->actual_length);
715 
716 	} else if (urb->actual_length > 0) {
717 		netdev_err(dev->netdev, "usb message length error (%u)\n",
718 			urb->actual_length);
719 		err = -EINVAL;
720 	}
721 
722 	return err;
723 }
724 
725 /*
726  * process outgoing packet
727  */
728 static int pcan_usb_encode_msg(struct peak_usb_device *dev, struct sk_buff *skb,
729 			       u8 *obuf, size_t *size)
730 {
731 	struct net_device *netdev = dev->netdev;
732 	struct net_device_stats *stats = &netdev->stats;
733 	struct can_frame *cf = (struct can_frame *)skb->data;
734 	u8 *pc;
735 
736 	obuf[0] = 2;
737 	obuf[1] = 1;
738 
739 	pc = obuf + PCAN_USB_MSG_HEADER_LEN;
740 
741 	/* status/len byte */
742 	*pc = cf->can_dlc;
743 	if (cf->can_id & CAN_RTR_FLAG)
744 		*pc |= PCAN_USB_STATUSLEN_RTR;
745 
746 	/* can id */
747 	if (cf->can_id & CAN_EFF_FLAG) {
748 		__le32 tmp32 = cpu_to_le32((cf->can_id & CAN_ERR_MASK) << 3);
749 
750 		*pc |= PCAN_USB_STATUSLEN_EXT_ID;
751 		memcpy(++pc, &tmp32, 4);
752 		pc += 4;
753 	} else {
754 		__le16 tmp16 = cpu_to_le16((cf->can_id & CAN_ERR_MASK) << 5);
755 
756 		memcpy(++pc, &tmp16, 2);
757 		pc += 2;
758 	}
759 
760 	/* can data */
761 	if (!(cf->can_id & CAN_RTR_FLAG)) {
762 		memcpy(pc, cf->data, cf->can_dlc);
763 		pc += cf->can_dlc;
764 	}
765 
766 	obuf[(*size)-1] = (u8)(stats->tx_packets & 0xff);
767 
768 	return 0;
769 }
770 
771 /*
772  * start interface
773  */
774 static int pcan_usb_start(struct peak_usb_device *dev)
775 {
776 	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
777 
778 	/* number of bits used in timestamps read from adapter struct */
779 	peak_usb_init_time_ref(&pdev->time_ref, &pcan_usb);
780 
781 	/* if revision greater than 3, can put silent mode on/off */
782 	if (dev->device_rev > 3) {
783 		int err;
784 
785 		err = pcan_usb_set_silent(dev,
786 				dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY);
787 		if (err)
788 			return err;
789 	}
790 
791 	return pcan_usb_set_ext_vcc(dev, 0);
792 }
793 
794 static int pcan_usb_init(struct peak_usb_device *dev)
795 {
796 	struct pcan_usb *pdev = container_of(dev, struct pcan_usb, dev);
797 	u32 serial_number;
798 	int err;
799 
800 	/* initialize a timer needed to wait for hardware restart */
801 	timer_setup(&pdev->restart_timer, pcan_usb_restart, 0);
802 
803 	/*
804 	 * explicit use of dev_xxx() instead of netdev_xxx() here:
805 	 * information displayed are related to the device itself, not
806 	 * to the canx netdevice.
807 	 */
808 	err = pcan_usb_get_serial(dev, &serial_number);
809 	if (err) {
810 		dev_err(dev->netdev->dev.parent,
811 			"unable to read %s serial number (err %d)\n",
812 			pcan_usb.name, err);
813 		return err;
814 	}
815 
816 	dev_info(dev->netdev->dev.parent,
817 		 "PEAK-System %s adapter hwrev %u serial %08X (%u channel)\n",
818 		 pcan_usb.name, dev->device_rev, serial_number,
819 		 pcan_usb.ctrl_count);
820 
821 	return 0;
822 }
823 
824 /*
825  * probe function for new PCAN-USB usb interface
826  */
827 static int pcan_usb_probe(struct usb_interface *intf)
828 {
829 	struct usb_host_interface *if_desc;
830 	int i;
831 
832 	if_desc = intf->altsetting;
833 
834 	/* check interface endpoint addresses */
835 	for (i = 0; i < if_desc->desc.bNumEndpoints; i++) {
836 		struct usb_endpoint_descriptor *ep = &if_desc->endpoint[i].desc;
837 
838 		switch (ep->bEndpointAddress) {
839 		case PCAN_USB_EP_CMDOUT:
840 		case PCAN_USB_EP_CMDIN:
841 		case PCAN_USB_EP_MSGOUT:
842 		case PCAN_USB_EP_MSGIN:
843 			break;
844 		default:
845 			return -ENODEV;
846 		}
847 	}
848 
849 	return 0;
850 }
851 
852 /*
853  * describe the PCAN-USB adapter
854  */
855 static const struct can_bittiming_const pcan_usb_const = {
856 	.name = "pcan_usb",
857 	.tseg1_min = 1,
858 	.tseg1_max = 16,
859 	.tseg2_min = 1,
860 	.tseg2_max = 8,
861 	.sjw_max = 4,
862 	.brp_min = 1,
863 	.brp_max = 64,
864 	.brp_inc = 1,
865 };
866 
867 const struct peak_usb_adapter pcan_usb = {
868 	.name = "PCAN-USB",
869 	.device_id = PCAN_USB_PRODUCT_ID,
870 	.ctrl_count = 1,
871 	.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES | CAN_CTRLMODE_LISTENONLY,
872 	.clock = {
873 		.freq = PCAN_USB_CRYSTAL_HZ / 2 ,
874 	},
875 	.bittiming_const = &pcan_usb_const,
876 
877 	/* size of device private data */
878 	.sizeof_dev_private = sizeof(struct pcan_usb),
879 
880 	/* timestamps usage */
881 	.ts_used_bits = 16,
882 	.ts_period = 24575, /* calibration period in ts. */
883 	.us_per_ts_scale = PCAN_USB_TS_US_PER_TICK, /* us=(ts*scale) */
884 	.us_per_ts_shift = PCAN_USB_TS_DIV_SHIFTER, /*  >> shift     */
885 
886 	/* give here messages in/out endpoints */
887 	.ep_msg_in = PCAN_USB_EP_MSGIN,
888 	.ep_msg_out = {PCAN_USB_EP_MSGOUT},
889 
890 	/* size of rx/tx usb buffers */
891 	.rx_buffer_size = PCAN_USB_RX_BUFFER_SIZE,
892 	.tx_buffer_size = PCAN_USB_TX_BUFFER_SIZE,
893 
894 	/* device callbacks */
895 	.intf_probe = pcan_usb_probe,
896 	.dev_init = pcan_usb_init,
897 	.dev_set_bus = pcan_usb_write_mode,
898 	.dev_set_bittiming = pcan_usb_set_bittiming,
899 	.dev_get_device_id = pcan_usb_get_device_id,
900 	.dev_decode_buf = pcan_usb_decode_buf,
901 	.dev_encode_msg = pcan_usb_encode_msg,
902 	.dev_start = pcan_usb_start,
903 	.dev_restart_async = pcan_usb_restart_async,
904 };
905