xref: /openbmc/linux/drivers/net/can/usb/gs_usb.c (revision 1edd0337)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* CAN driver for Geschwister Schneider USB/CAN devices
3  * and bytewerk.org candleLight USB CAN interfaces.
4  *
5  * Copyright (C) 2013-2016 Geschwister Schneider Technologie-,
6  * Entwicklungs- und Vertriebs UG (Haftungsbeschränkt).
7  * Copyright (C) 2016 Hubert Denkmair
8  *
9  * Many thanks to all socketcan devs!
10  */
11 
12 #include <linux/bitfield.h>
13 #include <linux/clocksource.h>
14 #include <linux/ethtool.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/netdevice.h>
18 #include <linux/signal.h>
19 #include <linux/timecounter.h>
20 #include <linux/units.h>
21 #include <linux/usb.h>
22 #include <linux/workqueue.h>
23 
24 #include <linux/can.h>
25 #include <linux/can/dev.h>
26 #include <linux/can/error.h>
27 
28 /* Device specific constants */
29 #define USB_GS_USB_1_VENDOR_ID 0x1d50
30 #define USB_GS_USB_1_PRODUCT_ID 0x606f
31 
32 #define USB_CANDLELIGHT_VENDOR_ID 0x1209
33 #define USB_CANDLELIGHT_PRODUCT_ID 0x2323
34 
35 #define USB_CES_CANEXT_FD_VENDOR_ID 0x1cd2
36 #define USB_CES_CANEXT_FD_PRODUCT_ID 0x606f
37 
38 #define USB_ABE_CANDEBUGGER_FD_VENDOR_ID 0x16d0
39 #define USB_ABE_CANDEBUGGER_FD_PRODUCT_ID 0x10b8
40 
41 #define GS_USB_ENDPOINT_IN 1
42 #define GS_USB_ENDPOINT_OUT 2
43 
44 /* Timestamp 32 bit timer runs at 1 MHz (1 µs tick). Worker accounts
45  * for timer overflow (will be after ~71 minutes)
46  */
47 #define GS_USB_TIMESTAMP_TIMER_HZ (1 * HZ_PER_MHZ)
48 #define GS_USB_TIMESTAMP_WORK_DELAY_SEC 1800
49 static_assert(GS_USB_TIMESTAMP_WORK_DELAY_SEC <
50 	      CYCLECOUNTER_MASK(32) / GS_USB_TIMESTAMP_TIMER_HZ / 2);
51 
52 /* Device specific constants */
53 enum gs_usb_breq {
54 	GS_USB_BREQ_HOST_FORMAT = 0,
55 	GS_USB_BREQ_BITTIMING,
56 	GS_USB_BREQ_MODE,
57 	GS_USB_BREQ_BERR,
58 	GS_USB_BREQ_BT_CONST,
59 	GS_USB_BREQ_DEVICE_CONFIG,
60 	GS_USB_BREQ_TIMESTAMP,
61 	GS_USB_BREQ_IDENTIFY,
62 	GS_USB_BREQ_GET_USER_ID,
63 	GS_USB_BREQ_QUIRK_CANTACT_PRO_DATA_BITTIMING = GS_USB_BREQ_GET_USER_ID,
64 	GS_USB_BREQ_SET_USER_ID,
65 	GS_USB_BREQ_DATA_BITTIMING,
66 	GS_USB_BREQ_BT_CONST_EXT,
67 	GS_USB_BREQ_SET_TERMINATION,
68 	GS_USB_BREQ_GET_TERMINATION,
69 	GS_USB_BREQ_GET_STATE,
70 };
71 
72 enum gs_can_mode {
73 	/* reset a channel. turns it off */
74 	GS_CAN_MODE_RESET = 0,
75 	/* starts a channel */
76 	GS_CAN_MODE_START
77 };
78 
79 enum gs_can_state {
80 	GS_CAN_STATE_ERROR_ACTIVE = 0,
81 	GS_CAN_STATE_ERROR_WARNING,
82 	GS_CAN_STATE_ERROR_PASSIVE,
83 	GS_CAN_STATE_BUS_OFF,
84 	GS_CAN_STATE_STOPPED,
85 	GS_CAN_STATE_SLEEPING
86 };
87 
88 enum gs_can_identify_mode {
89 	GS_CAN_IDENTIFY_OFF = 0,
90 	GS_CAN_IDENTIFY_ON
91 };
92 
93 enum gs_can_termination_state {
94 	GS_CAN_TERMINATION_STATE_OFF = 0,
95 	GS_CAN_TERMINATION_STATE_ON
96 };
97 
98 #define GS_USB_TERMINATION_DISABLED CAN_TERMINATION_DISABLED
99 #define GS_USB_TERMINATION_ENABLED 120
100 
101 /* data types passed between host and device */
102 
103 /* The firmware on the original USB2CAN by Geschwister Schneider
104  * Technologie Entwicklungs- und Vertriebs UG exchanges all data
105  * between the host and the device in host byte order. This is done
106  * with the struct gs_host_config::byte_order member, which is sent
107  * first to indicate the desired byte order.
108  *
109  * The widely used open source firmware candleLight doesn't support
110  * this feature and exchanges the data in little endian byte order.
111  */
112 struct gs_host_config {
113 	__le32 byte_order;
114 } __packed;
115 
116 struct gs_device_config {
117 	u8 reserved1;
118 	u8 reserved2;
119 	u8 reserved3;
120 	u8 icount;
121 	__le32 sw_version;
122 	__le32 hw_version;
123 } __packed;
124 
125 #define GS_CAN_MODE_NORMAL 0
126 #define GS_CAN_MODE_LISTEN_ONLY BIT(0)
127 #define GS_CAN_MODE_LOOP_BACK BIT(1)
128 #define GS_CAN_MODE_TRIPLE_SAMPLE BIT(2)
129 #define GS_CAN_MODE_ONE_SHOT BIT(3)
130 #define GS_CAN_MODE_HW_TIMESTAMP BIT(4)
131 /* GS_CAN_FEATURE_IDENTIFY BIT(5) */
132 /* GS_CAN_FEATURE_USER_ID BIT(6) */
133 #define GS_CAN_MODE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
134 #define GS_CAN_MODE_FD BIT(8)
135 /* GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9) */
136 /* GS_CAN_FEATURE_BT_CONST_EXT BIT(10) */
137 /* GS_CAN_FEATURE_TERMINATION BIT(11) */
138 #define GS_CAN_MODE_BERR_REPORTING BIT(12)
139 /* GS_CAN_FEATURE_GET_STATE BIT(13) */
140 
141 struct gs_device_mode {
142 	__le32 mode;
143 	__le32 flags;
144 } __packed;
145 
146 struct gs_device_state {
147 	__le32 state;
148 	__le32 rxerr;
149 	__le32 txerr;
150 } __packed;
151 
152 struct gs_device_bittiming {
153 	__le32 prop_seg;
154 	__le32 phase_seg1;
155 	__le32 phase_seg2;
156 	__le32 sjw;
157 	__le32 brp;
158 } __packed;
159 
160 struct gs_identify_mode {
161 	__le32 mode;
162 } __packed;
163 
164 struct gs_device_termination_state {
165 	__le32 state;
166 } __packed;
167 
168 #define GS_CAN_FEATURE_LISTEN_ONLY BIT(0)
169 #define GS_CAN_FEATURE_LOOP_BACK BIT(1)
170 #define GS_CAN_FEATURE_TRIPLE_SAMPLE BIT(2)
171 #define GS_CAN_FEATURE_ONE_SHOT BIT(3)
172 #define GS_CAN_FEATURE_HW_TIMESTAMP BIT(4)
173 #define GS_CAN_FEATURE_IDENTIFY BIT(5)
174 #define GS_CAN_FEATURE_USER_ID BIT(6)
175 #define GS_CAN_FEATURE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
176 #define GS_CAN_FEATURE_FD BIT(8)
177 #define GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9)
178 #define GS_CAN_FEATURE_BT_CONST_EXT BIT(10)
179 #define GS_CAN_FEATURE_TERMINATION BIT(11)
180 #define GS_CAN_FEATURE_BERR_REPORTING BIT(12)
181 #define GS_CAN_FEATURE_GET_STATE BIT(13)
182 #define GS_CAN_FEATURE_MASK GENMASK(13, 0)
183 
184 /* internal quirks - keep in GS_CAN_FEATURE space for now */
185 
186 /* CANtact Pro original firmware:
187  * BREQ DATA_BITTIMING overlaps with GET_USER_ID
188  */
189 #define GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO BIT(31)
190 
191 struct gs_device_bt_const {
192 	__le32 feature;
193 	__le32 fclk_can;
194 	__le32 tseg1_min;
195 	__le32 tseg1_max;
196 	__le32 tseg2_min;
197 	__le32 tseg2_max;
198 	__le32 sjw_max;
199 	__le32 brp_min;
200 	__le32 brp_max;
201 	__le32 brp_inc;
202 } __packed;
203 
204 struct gs_device_bt_const_extended {
205 	__le32 feature;
206 	__le32 fclk_can;
207 	__le32 tseg1_min;
208 	__le32 tseg1_max;
209 	__le32 tseg2_min;
210 	__le32 tseg2_max;
211 	__le32 sjw_max;
212 	__le32 brp_min;
213 	__le32 brp_max;
214 	__le32 brp_inc;
215 
216 	__le32 dtseg1_min;
217 	__le32 dtseg1_max;
218 	__le32 dtseg2_min;
219 	__le32 dtseg2_max;
220 	__le32 dsjw_max;
221 	__le32 dbrp_min;
222 	__le32 dbrp_max;
223 	__le32 dbrp_inc;
224 } __packed;
225 
226 #define GS_CAN_FLAG_OVERFLOW BIT(0)
227 #define GS_CAN_FLAG_FD BIT(1)
228 #define GS_CAN_FLAG_BRS BIT(2)
229 #define GS_CAN_FLAG_ESI BIT(3)
230 
231 struct classic_can {
232 	u8 data[8];
233 } __packed;
234 
235 struct classic_can_ts {
236 	u8 data[8];
237 	__le32 timestamp_us;
238 } __packed;
239 
240 struct classic_can_quirk {
241 	u8 data[8];
242 	u8 quirk;
243 } __packed;
244 
245 struct canfd {
246 	u8 data[64];
247 } __packed;
248 
249 struct canfd_ts {
250 	u8 data[64];
251 	__le32 timestamp_us;
252 } __packed;
253 
254 struct canfd_quirk {
255 	u8 data[64];
256 	u8 quirk;
257 } __packed;
258 
259 struct gs_host_frame {
260 	u32 echo_id;
261 	__le32 can_id;
262 
263 	u8 can_dlc;
264 	u8 channel;
265 	u8 flags;
266 	u8 reserved;
267 
268 	union {
269 		DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
270 		DECLARE_FLEX_ARRAY(struct classic_can_ts, classic_can_ts);
271 		DECLARE_FLEX_ARRAY(struct classic_can_quirk, classic_can_quirk);
272 		DECLARE_FLEX_ARRAY(struct canfd, canfd);
273 		DECLARE_FLEX_ARRAY(struct canfd_ts, canfd_ts);
274 		DECLARE_FLEX_ARRAY(struct canfd_quirk, canfd_quirk);
275 	};
276 } __packed;
277 /* The GS USB devices make use of the same flags and masks as in
278  * linux/can.h and linux/can/error.h, and no additional mapping is necessary.
279  */
280 
281 /* Only send a max of GS_MAX_TX_URBS frames per channel at a time. */
282 #define GS_MAX_TX_URBS 10
283 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
284 #define GS_MAX_RX_URBS 30
285 /* Maximum number of interfaces the driver supports per device.
286  * Current hardware only supports 3 interfaces. The future may vary.
287  */
288 #define GS_MAX_INTF 3
289 
290 struct gs_tx_context {
291 	struct gs_can *dev;
292 	unsigned int echo_id;
293 };
294 
295 struct gs_can {
296 	struct can_priv can; /* must be the first member */
297 
298 	struct gs_usb *parent;
299 
300 	struct net_device *netdev;
301 	struct usb_device *udev;
302 
303 	struct can_bittiming_const bt_const, data_bt_const;
304 	unsigned int channel;	/* channel number */
305 
306 	/* time counter for hardware timestamps */
307 	struct cyclecounter cc;
308 	struct timecounter tc;
309 	spinlock_t tc_lock; /* spinlock to guard access tc->cycle_last */
310 	struct delayed_work timestamp;
311 
312 	u32 feature;
313 	unsigned int hf_size_tx;
314 
315 	/* This lock prevents a race condition between xmit and receive. */
316 	spinlock_t tx_ctx_lock;
317 	struct gs_tx_context tx_context[GS_MAX_TX_URBS];
318 
319 	struct usb_anchor tx_submitted;
320 	atomic_t active_tx_urbs;
321 };
322 
323 /* usb interface struct */
324 struct gs_usb {
325 	struct gs_can *canch[GS_MAX_INTF];
326 	struct usb_anchor rx_submitted;
327 	struct usb_device *udev;
328 	unsigned int hf_size_rx;
329 	u8 active_channels;
330 };
331 
332 /* 'allocate' a tx context.
333  * returns a valid tx context or NULL if there is no space.
334  */
335 static struct gs_tx_context *gs_alloc_tx_context(struct gs_can *dev)
336 {
337 	int i = 0;
338 	unsigned long flags;
339 
340 	spin_lock_irqsave(&dev->tx_ctx_lock, flags);
341 
342 	for (; i < GS_MAX_TX_URBS; i++) {
343 		if (dev->tx_context[i].echo_id == GS_MAX_TX_URBS) {
344 			dev->tx_context[i].echo_id = i;
345 			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
346 			return &dev->tx_context[i];
347 		}
348 	}
349 
350 	spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
351 	return NULL;
352 }
353 
354 /* releases a tx context
355  */
356 static void gs_free_tx_context(struct gs_tx_context *txc)
357 {
358 	txc->echo_id = GS_MAX_TX_URBS;
359 }
360 
361 /* Get a tx context by id.
362  */
363 static struct gs_tx_context *gs_get_tx_context(struct gs_can *dev,
364 					       unsigned int id)
365 {
366 	unsigned long flags;
367 
368 	if (id < GS_MAX_TX_URBS) {
369 		spin_lock_irqsave(&dev->tx_ctx_lock, flags);
370 		if (dev->tx_context[id].echo_id == id) {
371 			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
372 			return &dev->tx_context[id];
373 		}
374 		spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
375 	}
376 	return NULL;
377 }
378 
379 static int gs_cmd_reset(struct gs_can *dev)
380 {
381 	struct gs_device_mode dm = {
382 		.mode = GS_CAN_MODE_RESET,
383 	};
384 
385 	return usb_control_msg_send(dev->udev, 0, GS_USB_BREQ_MODE,
386 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
387 				    dev->channel, 0, &dm, sizeof(dm), 1000,
388 				    GFP_KERNEL);
389 }
390 
391 static inline int gs_usb_get_timestamp(const struct gs_can *dev,
392 				       u32 *timestamp_p)
393 {
394 	__le32 timestamp;
395 	int rc;
396 
397 	rc = usb_control_msg_recv(dev->udev, 0, GS_USB_BREQ_TIMESTAMP,
398 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
399 				  dev->channel, 0,
400 				  &timestamp, sizeof(timestamp),
401 				  USB_CTRL_GET_TIMEOUT,
402 				  GFP_KERNEL);
403 	if (rc)
404 		return rc;
405 
406 	*timestamp_p = le32_to_cpu(timestamp);
407 
408 	return 0;
409 }
410 
411 static u64 gs_usb_timestamp_read(const struct cyclecounter *cc) __must_hold(&dev->tc_lock)
412 {
413 	struct gs_can *dev = container_of(cc, struct gs_can, cc);
414 	u32 timestamp = 0;
415 	int err;
416 
417 	lockdep_assert_held(&dev->tc_lock);
418 
419 	/* drop lock for synchronous USB transfer */
420 	spin_unlock_bh(&dev->tc_lock);
421 	err = gs_usb_get_timestamp(dev, &timestamp);
422 	spin_lock_bh(&dev->tc_lock);
423 	if (err)
424 		netdev_err(dev->netdev,
425 			   "Error %d while reading timestamp. HW timestamps may be inaccurate.",
426 			   err);
427 
428 	return timestamp;
429 }
430 
431 static void gs_usb_timestamp_work(struct work_struct *work)
432 {
433 	struct delayed_work *delayed_work = to_delayed_work(work);
434 	struct gs_can *dev;
435 
436 	dev = container_of(delayed_work, struct gs_can, timestamp);
437 	spin_lock_bh(&dev->tc_lock);
438 	timecounter_read(&dev->tc);
439 	spin_unlock_bh(&dev->tc_lock);
440 
441 	schedule_delayed_work(&dev->timestamp,
442 			      GS_USB_TIMESTAMP_WORK_DELAY_SEC * HZ);
443 }
444 
445 static void gs_usb_skb_set_timestamp(struct gs_can *dev,
446 				     struct sk_buff *skb, u32 timestamp)
447 {
448 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
449 	u64 ns;
450 
451 	spin_lock_bh(&dev->tc_lock);
452 	ns = timecounter_cyc2time(&dev->tc, timestamp);
453 	spin_unlock_bh(&dev->tc_lock);
454 
455 	hwtstamps->hwtstamp = ns_to_ktime(ns);
456 }
457 
458 static void gs_usb_timestamp_init(struct gs_can *dev)
459 {
460 	struct cyclecounter *cc = &dev->cc;
461 
462 	cc->read = gs_usb_timestamp_read;
463 	cc->mask = CYCLECOUNTER_MASK(32);
464 	cc->shift = 32 - bits_per(NSEC_PER_SEC / GS_USB_TIMESTAMP_TIMER_HZ);
465 	cc->mult = clocksource_hz2mult(GS_USB_TIMESTAMP_TIMER_HZ, cc->shift);
466 
467 	spin_lock_init(&dev->tc_lock);
468 	spin_lock_bh(&dev->tc_lock);
469 	timecounter_init(&dev->tc, &dev->cc, ktime_get_real_ns());
470 	spin_unlock_bh(&dev->tc_lock);
471 
472 	INIT_DELAYED_WORK(&dev->timestamp, gs_usb_timestamp_work);
473 	schedule_delayed_work(&dev->timestamp,
474 			      GS_USB_TIMESTAMP_WORK_DELAY_SEC * HZ);
475 }
476 
477 static void gs_usb_timestamp_stop(struct gs_can *dev)
478 {
479 	cancel_delayed_work_sync(&dev->timestamp);
480 }
481 
482 static void gs_update_state(struct gs_can *dev, struct can_frame *cf)
483 {
484 	struct can_device_stats *can_stats = &dev->can.can_stats;
485 
486 	if (cf->can_id & CAN_ERR_RESTARTED) {
487 		dev->can.state = CAN_STATE_ERROR_ACTIVE;
488 		can_stats->restarts++;
489 	} else if (cf->can_id & CAN_ERR_BUSOFF) {
490 		dev->can.state = CAN_STATE_BUS_OFF;
491 		can_stats->bus_off++;
492 	} else if (cf->can_id & CAN_ERR_CRTL) {
493 		if ((cf->data[1] & CAN_ERR_CRTL_TX_WARNING) ||
494 		    (cf->data[1] & CAN_ERR_CRTL_RX_WARNING)) {
495 			dev->can.state = CAN_STATE_ERROR_WARNING;
496 			can_stats->error_warning++;
497 		} else if ((cf->data[1] & CAN_ERR_CRTL_TX_PASSIVE) ||
498 			   (cf->data[1] & CAN_ERR_CRTL_RX_PASSIVE)) {
499 			dev->can.state = CAN_STATE_ERROR_PASSIVE;
500 			can_stats->error_passive++;
501 		} else {
502 			dev->can.state = CAN_STATE_ERROR_ACTIVE;
503 		}
504 	}
505 }
506 
507 static void gs_usb_set_timestamp(struct gs_can *dev, struct sk_buff *skb,
508 				 const struct gs_host_frame *hf)
509 {
510 	u32 timestamp;
511 
512 	if (!(dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP))
513 		return;
514 
515 	if (hf->flags & GS_CAN_FLAG_FD)
516 		timestamp = le32_to_cpu(hf->canfd_ts->timestamp_us);
517 	else
518 		timestamp = le32_to_cpu(hf->classic_can_ts->timestamp_us);
519 
520 	gs_usb_skb_set_timestamp(dev, skb, timestamp);
521 
522 	return;
523 }
524 
525 static void gs_usb_receive_bulk_callback(struct urb *urb)
526 {
527 	struct gs_usb *usbcan = urb->context;
528 	struct gs_can *dev;
529 	struct net_device *netdev;
530 	int rc;
531 	struct net_device_stats *stats;
532 	struct gs_host_frame *hf = urb->transfer_buffer;
533 	struct gs_tx_context *txc;
534 	struct can_frame *cf;
535 	struct canfd_frame *cfd;
536 	struct sk_buff *skb;
537 
538 	BUG_ON(!usbcan);
539 
540 	switch (urb->status) {
541 	case 0: /* success */
542 		break;
543 	case -ENOENT:
544 	case -ESHUTDOWN:
545 		return;
546 	default:
547 		/* do not resubmit aborted urbs. eg: when device goes down */
548 		return;
549 	}
550 
551 	/* device reports out of range channel id */
552 	if (hf->channel >= GS_MAX_INTF)
553 		goto device_detach;
554 
555 	dev = usbcan->canch[hf->channel];
556 
557 	netdev = dev->netdev;
558 	stats = &netdev->stats;
559 
560 	if (!netif_device_present(netdev))
561 		return;
562 
563 	if (hf->echo_id == -1) { /* normal rx */
564 		if (hf->flags & GS_CAN_FLAG_FD) {
565 			skb = alloc_canfd_skb(dev->netdev, &cfd);
566 			if (!skb)
567 				return;
568 
569 			cfd->can_id = le32_to_cpu(hf->can_id);
570 			cfd->len = can_fd_dlc2len(hf->can_dlc);
571 			if (hf->flags & GS_CAN_FLAG_BRS)
572 				cfd->flags |= CANFD_BRS;
573 			if (hf->flags & GS_CAN_FLAG_ESI)
574 				cfd->flags |= CANFD_ESI;
575 
576 			memcpy(cfd->data, hf->canfd->data, cfd->len);
577 		} else {
578 			skb = alloc_can_skb(dev->netdev, &cf);
579 			if (!skb)
580 				return;
581 
582 			cf->can_id = le32_to_cpu(hf->can_id);
583 			can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);
584 
585 			memcpy(cf->data, hf->classic_can->data, 8);
586 
587 			/* ERROR frames tell us information about the controller */
588 			if (le32_to_cpu(hf->can_id) & CAN_ERR_FLAG)
589 				gs_update_state(dev, cf);
590 		}
591 
592 		gs_usb_set_timestamp(dev, skb, hf);
593 
594 		netdev->stats.rx_packets++;
595 		netdev->stats.rx_bytes += hf->can_dlc;
596 
597 		netif_rx(skb);
598 	} else { /* echo_id == hf->echo_id */
599 		if (hf->echo_id >= GS_MAX_TX_URBS) {
600 			netdev_err(netdev,
601 				   "Unexpected out of range echo id %u\n",
602 				   hf->echo_id);
603 			goto resubmit_urb;
604 		}
605 
606 		txc = gs_get_tx_context(dev, hf->echo_id);
607 
608 		/* bad devices send bad echo_ids. */
609 		if (!txc) {
610 			netdev_err(netdev,
611 				   "Unexpected unused echo id %u\n",
612 				   hf->echo_id);
613 			goto resubmit_urb;
614 		}
615 
616 		skb = dev->can.echo_skb[hf->echo_id];
617 		gs_usb_set_timestamp(dev, skb, hf);
618 
619 		netdev->stats.tx_packets++;
620 		netdev->stats.tx_bytes += can_get_echo_skb(netdev, hf->echo_id,
621 							   NULL);
622 
623 		gs_free_tx_context(txc);
624 
625 		atomic_dec(&dev->active_tx_urbs);
626 
627 		netif_wake_queue(netdev);
628 	}
629 
630 	if (hf->flags & GS_CAN_FLAG_OVERFLOW) {
631 		skb = alloc_can_err_skb(netdev, &cf);
632 		if (!skb)
633 			goto resubmit_urb;
634 
635 		cf->can_id |= CAN_ERR_CRTL;
636 		cf->len = CAN_ERR_DLC;
637 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
638 		stats->rx_over_errors++;
639 		stats->rx_errors++;
640 		netif_rx(skb);
641 	}
642 
643  resubmit_urb:
644 	usb_fill_bulk_urb(urb, usbcan->udev,
645 			  usb_rcvbulkpipe(usbcan->udev, GS_USB_ENDPOINT_IN),
646 			  hf, dev->parent->hf_size_rx,
647 			  gs_usb_receive_bulk_callback, usbcan);
648 
649 	rc = usb_submit_urb(urb, GFP_ATOMIC);
650 
651 	/* USB failure take down all interfaces */
652 	if (rc == -ENODEV) {
653  device_detach:
654 		for (rc = 0; rc < GS_MAX_INTF; rc++) {
655 			if (usbcan->canch[rc])
656 				netif_device_detach(usbcan->canch[rc]->netdev);
657 		}
658 	}
659 }
660 
661 static int gs_usb_set_bittiming(struct net_device *netdev)
662 {
663 	struct gs_can *dev = netdev_priv(netdev);
664 	struct can_bittiming *bt = &dev->can.bittiming;
665 	struct gs_device_bittiming dbt = {
666 		.prop_seg = cpu_to_le32(bt->prop_seg),
667 		.phase_seg1 = cpu_to_le32(bt->phase_seg1),
668 		.phase_seg2 = cpu_to_le32(bt->phase_seg2),
669 		.sjw = cpu_to_le32(bt->sjw),
670 		.brp = cpu_to_le32(bt->brp),
671 	};
672 
673 	/* request bit timings */
674 	return usb_control_msg_send(dev->udev, 0, GS_USB_BREQ_BITTIMING,
675 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
676 				    dev->channel, 0, &dbt, sizeof(dbt), 1000,
677 				    GFP_KERNEL);
678 }
679 
680 static int gs_usb_set_data_bittiming(struct net_device *netdev)
681 {
682 	struct gs_can *dev = netdev_priv(netdev);
683 	struct can_bittiming *bt = &dev->can.data_bittiming;
684 	struct gs_device_bittiming dbt = {
685 		.prop_seg = cpu_to_le32(bt->prop_seg),
686 		.phase_seg1 = cpu_to_le32(bt->phase_seg1),
687 		.phase_seg2 = cpu_to_le32(bt->phase_seg2),
688 		.sjw = cpu_to_le32(bt->sjw),
689 		.brp = cpu_to_le32(bt->brp),
690 	};
691 	u8 request = GS_USB_BREQ_DATA_BITTIMING;
692 
693 	if (dev->feature & GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO)
694 		request = GS_USB_BREQ_QUIRK_CANTACT_PRO_DATA_BITTIMING;
695 
696 	/* request data bit timings */
697 	return usb_control_msg_send(dev->udev, 0, request,
698 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
699 				    dev->channel, 0, &dbt, sizeof(dbt), 1000,
700 				    GFP_KERNEL);
701 }
702 
703 static void gs_usb_xmit_callback(struct urb *urb)
704 {
705 	struct gs_tx_context *txc = urb->context;
706 	struct gs_can *dev = txc->dev;
707 	struct net_device *netdev = dev->netdev;
708 
709 	if (urb->status)
710 		netdev_info(netdev, "usb xmit fail %u\n", txc->echo_id);
711 }
712 
713 static netdev_tx_t gs_can_start_xmit(struct sk_buff *skb,
714 				     struct net_device *netdev)
715 {
716 	struct gs_can *dev = netdev_priv(netdev);
717 	struct net_device_stats *stats = &dev->netdev->stats;
718 	struct urb *urb;
719 	struct gs_host_frame *hf;
720 	struct can_frame *cf;
721 	struct canfd_frame *cfd;
722 	int rc;
723 	unsigned int idx;
724 	struct gs_tx_context *txc;
725 
726 	if (can_dev_dropped_skb(netdev, skb))
727 		return NETDEV_TX_OK;
728 
729 	/* find an empty context to keep track of transmission */
730 	txc = gs_alloc_tx_context(dev);
731 	if (!txc)
732 		return NETDEV_TX_BUSY;
733 
734 	/* create a URB, and a buffer for it */
735 	urb = usb_alloc_urb(0, GFP_ATOMIC);
736 	if (!urb)
737 		goto nomem_urb;
738 
739 	hf = kmalloc(dev->hf_size_tx, GFP_ATOMIC);
740 	if (!hf) {
741 		netdev_err(netdev, "No memory left for USB buffer\n");
742 		goto nomem_hf;
743 	}
744 
745 	idx = txc->echo_id;
746 
747 	if (idx >= GS_MAX_TX_URBS) {
748 		netdev_err(netdev, "Invalid tx context %u\n", idx);
749 		goto badidx;
750 	}
751 
752 	hf->echo_id = idx;
753 	hf->channel = dev->channel;
754 	hf->flags = 0;
755 	hf->reserved = 0;
756 
757 	if (can_is_canfd_skb(skb)) {
758 		cfd = (struct canfd_frame *)skb->data;
759 
760 		hf->can_id = cpu_to_le32(cfd->can_id);
761 		hf->can_dlc = can_fd_len2dlc(cfd->len);
762 		hf->flags |= GS_CAN_FLAG_FD;
763 		if (cfd->flags & CANFD_BRS)
764 			hf->flags |= GS_CAN_FLAG_BRS;
765 		if (cfd->flags & CANFD_ESI)
766 			hf->flags |= GS_CAN_FLAG_ESI;
767 
768 		memcpy(hf->canfd->data, cfd->data, cfd->len);
769 	} else {
770 		cf = (struct can_frame *)skb->data;
771 
772 		hf->can_id = cpu_to_le32(cf->can_id);
773 		hf->can_dlc = can_get_cc_dlc(cf, dev->can.ctrlmode);
774 
775 		memcpy(hf->classic_can->data, cf->data, cf->len);
776 	}
777 
778 	usb_fill_bulk_urb(urb, dev->udev,
779 			  usb_sndbulkpipe(dev->udev, GS_USB_ENDPOINT_OUT),
780 			  hf, dev->hf_size_tx,
781 			  gs_usb_xmit_callback, txc);
782 
783 	urb->transfer_flags |= URB_FREE_BUFFER;
784 	usb_anchor_urb(urb, &dev->tx_submitted);
785 
786 	can_put_echo_skb(skb, netdev, idx, 0);
787 
788 	atomic_inc(&dev->active_tx_urbs);
789 
790 	rc = usb_submit_urb(urb, GFP_ATOMIC);
791 	if (unlikely(rc)) {			/* usb send failed */
792 		atomic_dec(&dev->active_tx_urbs);
793 
794 		can_free_echo_skb(netdev, idx, NULL);
795 		gs_free_tx_context(txc);
796 
797 		usb_unanchor_urb(urb);
798 
799 		if (rc == -ENODEV) {
800 			netif_device_detach(netdev);
801 		} else {
802 			netdev_err(netdev, "usb_submit failed (err=%d)\n", rc);
803 			stats->tx_dropped++;
804 		}
805 	} else {
806 		/* Slow down tx path */
807 		if (atomic_read(&dev->active_tx_urbs) >= GS_MAX_TX_URBS)
808 			netif_stop_queue(netdev);
809 	}
810 
811 	/* let usb core take care of this urb */
812 	usb_free_urb(urb);
813 
814 	return NETDEV_TX_OK;
815 
816  badidx:
817 	kfree(hf);
818  nomem_hf:
819 	usb_free_urb(urb);
820 
821  nomem_urb:
822 	gs_free_tx_context(txc);
823 	dev_kfree_skb(skb);
824 	stats->tx_dropped++;
825 	return NETDEV_TX_OK;
826 }
827 
828 static int gs_can_open(struct net_device *netdev)
829 {
830 	struct gs_can *dev = netdev_priv(netdev);
831 	struct gs_usb *parent = dev->parent;
832 	struct gs_device_mode dm = {
833 		.mode = cpu_to_le32(GS_CAN_MODE_START),
834 	};
835 	struct gs_host_frame *hf;
836 	u32 ctrlmode;
837 	u32 flags = 0;
838 	int rc, i;
839 
840 	rc = open_candev(netdev);
841 	if (rc)
842 		return rc;
843 
844 	ctrlmode = dev->can.ctrlmode;
845 	if (ctrlmode & CAN_CTRLMODE_FD) {
846 		if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
847 			dev->hf_size_tx = struct_size(hf, canfd_quirk, 1);
848 		else
849 			dev->hf_size_tx = struct_size(hf, canfd, 1);
850 	} else {
851 		if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
852 			dev->hf_size_tx = struct_size(hf, classic_can_quirk, 1);
853 		else
854 			dev->hf_size_tx = struct_size(hf, classic_can, 1);
855 	}
856 
857 	if (!parent->active_channels) {
858 		for (i = 0; i < GS_MAX_RX_URBS; i++) {
859 			struct urb *urb;
860 			u8 *buf;
861 
862 			/* alloc rx urb */
863 			urb = usb_alloc_urb(0, GFP_KERNEL);
864 			if (!urb)
865 				return -ENOMEM;
866 
867 			/* alloc rx buffer */
868 			buf = kmalloc(dev->parent->hf_size_rx,
869 				      GFP_KERNEL);
870 			if (!buf) {
871 				netdev_err(netdev,
872 					   "No memory left for USB buffer\n");
873 				usb_free_urb(urb);
874 				return -ENOMEM;
875 			}
876 
877 			/* fill, anchor, and submit rx urb */
878 			usb_fill_bulk_urb(urb,
879 					  dev->udev,
880 					  usb_rcvbulkpipe(dev->udev,
881 							  GS_USB_ENDPOINT_IN),
882 					  buf,
883 					  dev->parent->hf_size_rx,
884 					  gs_usb_receive_bulk_callback, parent);
885 			urb->transfer_flags |= URB_FREE_BUFFER;
886 
887 			usb_anchor_urb(urb, &parent->rx_submitted);
888 
889 			rc = usb_submit_urb(urb, GFP_KERNEL);
890 			if (rc) {
891 				if (rc == -ENODEV)
892 					netif_device_detach(dev->netdev);
893 
894 				netdev_err(netdev,
895 					   "usb_submit failed (err=%d)\n", rc);
896 
897 				usb_unanchor_urb(urb);
898 				usb_free_urb(urb);
899 				break;
900 			}
901 
902 			/* Drop reference,
903 			 * USB core will take care of freeing it
904 			 */
905 			usb_free_urb(urb);
906 		}
907 	}
908 
909 	/* flags */
910 	if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
911 		flags |= GS_CAN_MODE_LOOP_BACK;
912 
913 	if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
914 		flags |= GS_CAN_MODE_LISTEN_ONLY;
915 
916 	if (ctrlmode & CAN_CTRLMODE_3_SAMPLES)
917 		flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
918 
919 	if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
920 		flags |= GS_CAN_MODE_ONE_SHOT;
921 
922 	if (ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
923 		flags |= GS_CAN_MODE_BERR_REPORTING;
924 
925 	if (ctrlmode & CAN_CTRLMODE_FD)
926 		flags |= GS_CAN_MODE_FD;
927 
928 	/* if hardware supports timestamps, enable it */
929 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP) {
930 		flags |= GS_CAN_MODE_HW_TIMESTAMP;
931 
932 		/* start polling timestamp */
933 		gs_usb_timestamp_init(dev);
934 	}
935 
936 	/* finally start device */
937 	dev->can.state = CAN_STATE_ERROR_ACTIVE;
938 	dm.flags = cpu_to_le32(flags);
939 	rc = usb_control_msg_send(dev->udev, 0, GS_USB_BREQ_MODE,
940 				  USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
941 				  dev->channel, 0, &dm, sizeof(dm), 1000,
942 				  GFP_KERNEL);
943 	if (rc) {
944 		netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
945 		if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
946 			gs_usb_timestamp_stop(dev);
947 		dev->can.state = CAN_STATE_STOPPED;
948 		return rc;
949 	}
950 
951 	parent->active_channels++;
952 	if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
953 		netif_start_queue(netdev);
954 
955 	return 0;
956 }
957 
958 static int gs_usb_get_state(const struct net_device *netdev,
959 			    struct can_berr_counter *bec,
960 			    enum can_state *state)
961 {
962 	struct gs_can *dev = netdev_priv(netdev);
963 	struct gs_device_state ds;
964 	int rc;
965 
966 	rc = usb_control_msg_recv(dev->udev, 0, GS_USB_BREQ_GET_STATE,
967 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
968 				  dev->channel, 0,
969 				  &ds, sizeof(ds),
970 				  USB_CTRL_GET_TIMEOUT,
971 				  GFP_KERNEL);
972 	if (rc)
973 		return rc;
974 
975 	if (le32_to_cpu(ds.state) >= CAN_STATE_MAX)
976 		return -EOPNOTSUPP;
977 
978 	*state = le32_to_cpu(ds.state);
979 	bec->txerr = le32_to_cpu(ds.txerr);
980 	bec->rxerr = le32_to_cpu(ds.rxerr);
981 
982 	return 0;
983 }
984 
985 static int gs_usb_can_get_berr_counter(const struct net_device *netdev,
986 				       struct can_berr_counter *bec)
987 {
988 	enum can_state state;
989 
990 	return gs_usb_get_state(netdev, bec, &state);
991 }
992 
993 static int gs_can_close(struct net_device *netdev)
994 {
995 	int rc;
996 	struct gs_can *dev = netdev_priv(netdev);
997 	struct gs_usb *parent = dev->parent;
998 
999 	netif_stop_queue(netdev);
1000 
1001 	/* stop polling timestamp */
1002 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1003 		gs_usb_timestamp_stop(dev);
1004 
1005 	/* Stop polling */
1006 	parent->active_channels--;
1007 	if (!parent->active_channels) {
1008 		usb_kill_anchored_urbs(&parent->rx_submitted);
1009 	}
1010 
1011 	/* Stop sending URBs */
1012 	usb_kill_anchored_urbs(&dev->tx_submitted);
1013 	atomic_set(&dev->active_tx_urbs, 0);
1014 
1015 	/* reset the device */
1016 	rc = gs_cmd_reset(dev);
1017 	if (rc < 0)
1018 		netdev_warn(netdev, "Couldn't shutdown device (err=%d)", rc);
1019 
1020 	/* reset tx contexts */
1021 	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
1022 		dev->tx_context[rc].dev = dev;
1023 		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
1024 	}
1025 
1026 	/* close the netdev */
1027 	close_candev(netdev);
1028 
1029 	return 0;
1030 }
1031 
1032 static int gs_can_eth_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
1033 {
1034 	const struct gs_can *dev = netdev_priv(netdev);
1035 
1036 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1037 		return can_eth_ioctl_hwts(netdev, ifr, cmd);
1038 
1039 	return -EOPNOTSUPP;
1040 }
1041 
1042 static const struct net_device_ops gs_usb_netdev_ops = {
1043 	.ndo_open = gs_can_open,
1044 	.ndo_stop = gs_can_close,
1045 	.ndo_start_xmit = gs_can_start_xmit,
1046 	.ndo_change_mtu = can_change_mtu,
1047 	.ndo_eth_ioctl = gs_can_eth_ioctl,
1048 };
1049 
1050 static int gs_usb_set_identify(struct net_device *netdev, bool do_identify)
1051 {
1052 	struct gs_can *dev = netdev_priv(netdev);
1053 	struct gs_identify_mode imode;
1054 
1055 	if (do_identify)
1056 		imode.mode = cpu_to_le32(GS_CAN_IDENTIFY_ON);
1057 	else
1058 		imode.mode = cpu_to_le32(GS_CAN_IDENTIFY_OFF);
1059 
1060 	return usb_control_msg_send(dev->udev, 0, GS_USB_BREQ_IDENTIFY,
1061 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1062 				    dev->channel, 0, &imode, sizeof(imode), 100,
1063 				    GFP_KERNEL);
1064 }
1065 
1066 /* blink LED's for finding the this interface */
1067 static int gs_usb_set_phys_id(struct net_device *netdev,
1068 			      enum ethtool_phys_id_state state)
1069 {
1070 	const struct gs_can *dev = netdev_priv(netdev);
1071 	int rc = 0;
1072 
1073 	if (!(dev->feature & GS_CAN_FEATURE_IDENTIFY))
1074 		return -EOPNOTSUPP;
1075 
1076 	switch (state) {
1077 	case ETHTOOL_ID_ACTIVE:
1078 		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_ON);
1079 		break;
1080 	case ETHTOOL_ID_INACTIVE:
1081 		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_OFF);
1082 		break;
1083 	default:
1084 		break;
1085 	}
1086 
1087 	return rc;
1088 }
1089 
1090 static int gs_usb_get_ts_info(struct net_device *netdev,
1091 			      struct ethtool_ts_info *info)
1092 {
1093 	struct gs_can *dev = netdev_priv(netdev);
1094 
1095 	/* report if device supports HW timestamps */
1096 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1097 		return can_ethtool_op_get_ts_info_hwts(netdev, info);
1098 
1099 	return ethtool_op_get_ts_info(netdev, info);
1100 }
1101 
1102 static const struct ethtool_ops gs_usb_ethtool_ops = {
1103 	.set_phys_id = gs_usb_set_phys_id,
1104 	.get_ts_info = gs_usb_get_ts_info,
1105 };
1106 
1107 static int gs_usb_get_termination(struct net_device *netdev, u16 *term)
1108 {
1109 	struct gs_can *dev = netdev_priv(netdev);
1110 	struct gs_device_termination_state term_state;
1111 	int rc;
1112 
1113 	rc = usb_control_msg_recv(dev->udev, 0, GS_USB_BREQ_GET_TERMINATION,
1114 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1115 				  dev->channel, 0,
1116 				  &term_state, sizeof(term_state), 1000,
1117 				  GFP_KERNEL);
1118 	if (rc)
1119 		return rc;
1120 
1121 	if (term_state.state == cpu_to_le32(GS_CAN_TERMINATION_STATE_ON))
1122 		*term = GS_USB_TERMINATION_ENABLED;
1123 	else
1124 		*term = GS_USB_TERMINATION_DISABLED;
1125 
1126 	return 0;
1127 }
1128 
1129 static int gs_usb_set_termination(struct net_device *netdev, u16 term)
1130 {
1131 	struct gs_can *dev = netdev_priv(netdev);
1132 	struct gs_device_termination_state term_state;
1133 
1134 	if (term == GS_USB_TERMINATION_ENABLED)
1135 		term_state.state = cpu_to_le32(GS_CAN_TERMINATION_STATE_ON);
1136 	else
1137 		term_state.state = cpu_to_le32(GS_CAN_TERMINATION_STATE_OFF);
1138 
1139 	return usb_control_msg_send(dev->udev, 0, GS_USB_BREQ_SET_TERMINATION,
1140 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1141 				    dev->channel, 0,
1142 				    &term_state, sizeof(term_state), 1000,
1143 				    GFP_KERNEL);
1144 }
1145 
1146 static const u16 gs_usb_termination_const[] = {
1147 	GS_USB_TERMINATION_DISABLED,
1148 	GS_USB_TERMINATION_ENABLED
1149 };
1150 
1151 static struct gs_can *gs_make_candev(unsigned int channel,
1152 				     struct usb_interface *intf,
1153 				     struct gs_device_config *dconf)
1154 {
1155 	struct gs_can *dev;
1156 	struct net_device *netdev;
1157 	int rc;
1158 	struct gs_device_bt_const_extended bt_const_extended;
1159 	struct gs_device_bt_const bt_const;
1160 	u32 feature;
1161 
1162 	/* fetch bit timing constants */
1163 	rc = usb_control_msg_recv(interface_to_usbdev(intf), 0,
1164 				  GS_USB_BREQ_BT_CONST,
1165 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1166 				  channel, 0, &bt_const, sizeof(bt_const), 1000,
1167 				  GFP_KERNEL);
1168 
1169 	if (rc) {
1170 		dev_err(&intf->dev,
1171 			"Couldn't get bit timing const for channel %d (%pe)\n",
1172 			channel, ERR_PTR(rc));
1173 		return ERR_PTR(rc);
1174 	}
1175 
1176 	/* create netdev */
1177 	netdev = alloc_candev(sizeof(struct gs_can), GS_MAX_TX_URBS);
1178 	if (!netdev) {
1179 		dev_err(&intf->dev, "Couldn't allocate candev\n");
1180 		return ERR_PTR(-ENOMEM);
1181 	}
1182 
1183 	dev = netdev_priv(netdev);
1184 
1185 	netdev->netdev_ops = &gs_usb_netdev_ops;
1186 	netdev->ethtool_ops = &gs_usb_ethtool_ops;
1187 
1188 	netdev->flags |= IFF_ECHO; /* we support full roundtrip echo */
1189 	netdev->dev_id = channel;
1190 
1191 	/* dev setup */
1192 	strcpy(dev->bt_const.name, KBUILD_MODNAME);
1193 	dev->bt_const.tseg1_min = le32_to_cpu(bt_const.tseg1_min);
1194 	dev->bt_const.tseg1_max = le32_to_cpu(bt_const.tseg1_max);
1195 	dev->bt_const.tseg2_min = le32_to_cpu(bt_const.tseg2_min);
1196 	dev->bt_const.tseg2_max = le32_to_cpu(bt_const.tseg2_max);
1197 	dev->bt_const.sjw_max = le32_to_cpu(bt_const.sjw_max);
1198 	dev->bt_const.brp_min = le32_to_cpu(bt_const.brp_min);
1199 	dev->bt_const.brp_max = le32_to_cpu(bt_const.brp_max);
1200 	dev->bt_const.brp_inc = le32_to_cpu(bt_const.brp_inc);
1201 
1202 	dev->udev = interface_to_usbdev(intf);
1203 	dev->netdev = netdev;
1204 	dev->channel = channel;
1205 
1206 	init_usb_anchor(&dev->tx_submitted);
1207 	atomic_set(&dev->active_tx_urbs, 0);
1208 	spin_lock_init(&dev->tx_ctx_lock);
1209 	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
1210 		dev->tx_context[rc].dev = dev;
1211 		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
1212 	}
1213 
1214 	/* can setup */
1215 	dev->can.state = CAN_STATE_STOPPED;
1216 	dev->can.clock.freq = le32_to_cpu(bt_const.fclk_can);
1217 	dev->can.bittiming_const = &dev->bt_const;
1218 	dev->can.do_set_bittiming = gs_usb_set_bittiming;
1219 
1220 	dev->can.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC;
1221 
1222 	feature = le32_to_cpu(bt_const.feature);
1223 	dev->feature = FIELD_GET(GS_CAN_FEATURE_MASK, feature);
1224 	if (feature & GS_CAN_FEATURE_LISTEN_ONLY)
1225 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
1226 
1227 	if (feature & GS_CAN_FEATURE_LOOP_BACK)
1228 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
1229 
1230 	if (feature & GS_CAN_FEATURE_TRIPLE_SAMPLE)
1231 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
1232 
1233 	if (feature & GS_CAN_FEATURE_ONE_SHOT)
1234 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
1235 
1236 	if (feature & GS_CAN_FEATURE_FD) {
1237 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
1238 		/* The data bit timing will be overwritten, if
1239 		 * GS_CAN_FEATURE_BT_CONST_EXT is set.
1240 		 */
1241 		dev->can.data_bittiming_const = &dev->bt_const;
1242 		dev->can.do_set_data_bittiming = gs_usb_set_data_bittiming;
1243 	}
1244 
1245 	if (feature & GS_CAN_FEATURE_TERMINATION) {
1246 		rc = gs_usb_get_termination(netdev, &dev->can.termination);
1247 		if (rc) {
1248 			dev->feature &= ~GS_CAN_FEATURE_TERMINATION;
1249 
1250 			dev_info(&intf->dev,
1251 				 "Disabling termination support for channel %d (%pe)\n",
1252 				 channel, ERR_PTR(rc));
1253 		} else {
1254 			dev->can.termination_const = gs_usb_termination_const;
1255 			dev->can.termination_const_cnt = ARRAY_SIZE(gs_usb_termination_const);
1256 			dev->can.do_set_termination = gs_usb_set_termination;
1257 		}
1258 	}
1259 
1260 	if (feature & GS_CAN_FEATURE_BERR_REPORTING)
1261 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_BERR_REPORTING;
1262 
1263 	if (feature & GS_CAN_FEATURE_GET_STATE)
1264 		dev->can.do_get_berr_counter = gs_usb_can_get_berr_counter;
1265 
1266 	/* The CANtact Pro from LinkLayer Labs is based on the
1267 	 * LPC54616 µC, which is affected by the NXP LPC USB transfer
1268 	 * erratum. However, the current firmware (version 2) doesn't
1269 	 * set the GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX bit. Set the
1270 	 * feature GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX to workaround
1271 	 * this issue.
1272 	 *
1273 	 * For the GS_USB_BREQ_DATA_BITTIMING USB control message the
1274 	 * CANtact Pro firmware uses a request value, which is already
1275 	 * used by the candleLight firmware for a different purpose
1276 	 * (GS_USB_BREQ_GET_USER_ID). Set the feature
1277 	 * GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO to workaround this
1278 	 * issue.
1279 	 */
1280 	if (dev->udev->descriptor.idVendor == cpu_to_le16(USB_GS_USB_1_VENDOR_ID) &&
1281 	    dev->udev->descriptor.idProduct == cpu_to_le16(USB_GS_USB_1_PRODUCT_ID) &&
1282 	    dev->udev->manufacturer && dev->udev->product &&
1283 	    !strcmp(dev->udev->manufacturer, "LinkLayer Labs") &&
1284 	    !strcmp(dev->udev->product, "CANtact Pro") &&
1285 	    (le32_to_cpu(dconf->sw_version) <= 2))
1286 		dev->feature |= GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX |
1287 			GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO;
1288 
1289 	/* GS_CAN_FEATURE_IDENTIFY is only supported for sw_version > 1 */
1290 	if (!(le32_to_cpu(dconf->sw_version) > 1 &&
1291 	      feature & GS_CAN_FEATURE_IDENTIFY))
1292 		dev->feature &= ~GS_CAN_FEATURE_IDENTIFY;
1293 
1294 	/* fetch extended bit timing constants if device has feature
1295 	 * GS_CAN_FEATURE_FD and GS_CAN_FEATURE_BT_CONST_EXT
1296 	 */
1297 	if (feature & GS_CAN_FEATURE_FD &&
1298 	    feature & GS_CAN_FEATURE_BT_CONST_EXT) {
1299 		rc = usb_control_msg_recv(interface_to_usbdev(intf), 0,
1300 					  GS_USB_BREQ_BT_CONST_EXT,
1301 					  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1302 					  channel, 0, &bt_const_extended,
1303 					  sizeof(bt_const_extended),
1304 					  1000, GFP_KERNEL);
1305 		if (rc) {
1306 			dev_err(&intf->dev,
1307 				"Couldn't get extended bit timing const for channel %d (%pe)\n",
1308 				channel, ERR_PTR(rc));
1309 			goto out_free_candev;
1310 		}
1311 
1312 		strcpy(dev->data_bt_const.name, KBUILD_MODNAME);
1313 		dev->data_bt_const.tseg1_min = le32_to_cpu(bt_const_extended.dtseg1_min);
1314 		dev->data_bt_const.tseg1_max = le32_to_cpu(bt_const_extended.dtseg1_max);
1315 		dev->data_bt_const.tseg2_min = le32_to_cpu(bt_const_extended.dtseg2_min);
1316 		dev->data_bt_const.tseg2_max = le32_to_cpu(bt_const_extended.dtseg2_max);
1317 		dev->data_bt_const.sjw_max = le32_to_cpu(bt_const_extended.dsjw_max);
1318 		dev->data_bt_const.brp_min = le32_to_cpu(bt_const_extended.dbrp_min);
1319 		dev->data_bt_const.brp_max = le32_to_cpu(bt_const_extended.dbrp_max);
1320 		dev->data_bt_const.brp_inc = le32_to_cpu(bt_const_extended.dbrp_inc);
1321 
1322 		dev->can.data_bittiming_const = &dev->data_bt_const;
1323 	}
1324 
1325 	SET_NETDEV_DEV(netdev, &intf->dev);
1326 
1327 	rc = register_candev(dev->netdev);
1328 	if (rc) {
1329 		dev_err(&intf->dev,
1330 			"Couldn't register candev for channel %d (%pe)\n",
1331 			channel, ERR_PTR(rc));
1332 		goto out_free_candev;
1333 	}
1334 
1335 	return dev;
1336 
1337  out_free_candev:
1338 	free_candev(dev->netdev);
1339 	return ERR_PTR(rc);
1340 }
1341 
1342 static void gs_destroy_candev(struct gs_can *dev)
1343 {
1344 	unregister_candev(dev->netdev);
1345 	usb_kill_anchored_urbs(&dev->tx_submitted);
1346 	free_candev(dev->netdev);
1347 }
1348 
1349 static int gs_usb_probe(struct usb_interface *intf,
1350 			const struct usb_device_id *id)
1351 {
1352 	struct usb_device *udev = interface_to_usbdev(intf);
1353 	struct gs_host_frame *hf;
1354 	struct gs_usb *dev;
1355 	struct gs_host_config hconf = {
1356 		.byte_order = cpu_to_le32(0x0000beef),
1357 	};
1358 	struct gs_device_config dconf;
1359 	unsigned int icount, i;
1360 	int rc;
1361 
1362 	/* send host config */
1363 	rc = usb_control_msg_send(udev, 0,
1364 				  GS_USB_BREQ_HOST_FORMAT,
1365 				  USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1366 				  1, intf->cur_altsetting->desc.bInterfaceNumber,
1367 				  &hconf, sizeof(hconf), 1000,
1368 				  GFP_KERNEL);
1369 	if (rc) {
1370 		dev_err(&intf->dev, "Couldn't send data format (err=%d)\n", rc);
1371 		return rc;
1372 	}
1373 
1374 	/* read device config */
1375 	rc = usb_control_msg_recv(udev, 0,
1376 				  GS_USB_BREQ_DEVICE_CONFIG,
1377 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1378 				  1, intf->cur_altsetting->desc.bInterfaceNumber,
1379 				  &dconf, sizeof(dconf), 1000,
1380 				  GFP_KERNEL);
1381 	if (rc) {
1382 		dev_err(&intf->dev, "Couldn't get device config: (err=%d)\n",
1383 			rc);
1384 		return rc;
1385 	}
1386 
1387 	icount = dconf.icount + 1;
1388 	dev_info(&intf->dev, "Configuring for %u interfaces\n", icount);
1389 
1390 	if (icount > GS_MAX_INTF) {
1391 		dev_err(&intf->dev,
1392 			"Driver cannot handle more that %u CAN interfaces\n",
1393 			GS_MAX_INTF);
1394 		return -EINVAL;
1395 	}
1396 
1397 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1398 	if (!dev)
1399 		return -ENOMEM;
1400 
1401 	init_usb_anchor(&dev->rx_submitted);
1402 
1403 	usb_set_intfdata(intf, dev);
1404 	dev->udev = udev;
1405 
1406 	for (i = 0; i < icount; i++) {
1407 		unsigned int hf_size_rx = 0;
1408 
1409 		dev->canch[i] = gs_make_candev(i, intf, &dconf);
1410 		if (IS_ERR_OR_NULL(dev->canch[i])) {
1411 			/* save error code to return later */
1412 			rc = PTR_ERR(dev->canch[i]);
1413 
1414 			/* on failure destroy previously created candevs */
1415 			icount = i;
1416 			for (i = 0; i < icount; i++)
1417 				gs_destroy_candev(dev->canch[i]);
1418 
1419 			usb_kill_anchored_urbs(&dev->rx_submitted);
1420 			kfree(dev);
1421 			return rc;
1422 		}
1423 		dev->canch[i]->parent = dev;
1424 
1425 		/* set RX packet size based on FD and if hardware
1426                 * timestamps are supported.
1427 		*/
1428 		if (dev->canch[i]->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
1429 			if (dev->canch[i]->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1430 				hf_size_rx = struct_size(hf, canfd_ts, 1);
1431 			else
1432 				hf_size_rx = struct_size(hf, canfd, 1);
1433 		} else {
1434 			if (dev->canch[i]->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1435 				hf_size_rx = struct_size(hf, classic_can_ts, 1);
1436 			else
1437 				hf_size_rx = struct_size(hf, classic_can, 1);
1438 		}
1439 		dev->hf_size_rx = max(dev->hf_size_rx, hf_size_rx);
1440 	}
1441 
1442 	return 0;
1443 }
1444 
1445 static void gs_usb_disconnect(struct usb_interface *intf)
1446 {
1447 	struct gs_usb *dev = usb_get_intfdata(intf);
1448 	unsigned int i;
1449 
1450 	usb_set_intfdata(intf, NULL);
1451 
1452 	if (!dev) {
1453 		dev_err(&intf->dev, "Disconnect (nodata)\n");
1454 		return;
1455 	}
1456 
1457 	for (i = 0; i < GS_MAX_INTF; i++)
1458 		if (dev->canch[i])
1459 			gs_destroy_candev(dev->canch[i]);
1460 
1461 	usb_kill_anchored_urbs(&dev->rx_submitted);
1462 	kfree(dev);
1463 }
1464 
1465 static const struct usb_device_id gs_usb_table[] = {
1466 	{ USB_DEVICE_INTERFACE_NUMBER(USB_GS_USB_1_VENDOR_ID,
1467 				      USB_GS_USB_1_PRODUCT_ID, 0) },
1468 	{ USB_DEVICE_INTERFACE_NUMBER(USB_CANDLELIGHT_VENDOR_ID,
1469 				      USB_CANDLELIGHT_PRODUCT_ID, 0) },
1470 	{ USB_DEVICE_INTERFACE_NUMBER(USB_CES_CANEXT_FD_VENDOR_ID,
1471 				      USB_CES_CANEXT_FD_PRODUCT_ID, 0) },
1472 	{ USB_DEVICE_INTERFACE_NUMBER(USB_ABE_CANDEBUGGER_FD_VENDOR_ID,
1473 				      USB_ABE_CANDEBUGGER_FD_PRODUCT_ID, 0) },
1474 	{} /* Terminating entry */
1475 };
1476 
1477 MODULE_DEVICE_TABLE(usb, gs_usb_table);
1478 
1479 static struct usb_driver gs_usb_driver = {
1480 	.name = KBUILD_MODNAME,
1481 	.probe = gs_usb_probe,
1482 	.disconnect = gs_usb_disconnect,
1483 	.id_table = gs_usb_table,
1484 };
1485 
1486 module_usb_driver(gs_usb_driver);
1487 
1488 MODULE_AUTHOR("Maximilian Schneider <mws@schneidersoft.net>");
1489 MODULE_DESCRIPTION(
1490 "Socket CAN device driver for Geschwister Schneider Technologie-, "
1491 "Entwicklungs- und Vertriebs UG. USB2.0 to CAN interfaces\n"
1492 "and bytewerk.org candleLight USB CAN interfaces.");
1493 MODULE_LICENSE("GPL v2");
1494