xref: /linux/drivers/net/can/usb/gs_usb.c (revision 31354121bf03dac6498a4236928a38490745d601)
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 };
70 
71 enum gs_can_mode {
72 	/* reset a channel. turns it off */
73 	GS_CAN_MODE_RESET = 0,
74 	/* starts a channel */
75 	GS_CAN_MODE_START
76 };
77 
78 enum gs_can_state {
79 	GS_CAN_STATE_ERROR_ACTIVE = 0,
80 	GS_CAN_STATE_ERROR_WARNING,
81 	GS_CAN_STATE_ERROR_PASSIVE,
82 	GS_CAN_STATE_BUS_OFF,
83 	GS_CAN_STATE_STOPPED,
84 	GS_CAN_STATE_SLEEPING
85 };
86 
87 enum gs_can_identify_mode {
88 	GS_CAN_IDENTIFY_OFF = 0,
89 	GS_CAN_IDENTIFY_ON
90 };
91 
92 enum gs_can_termination_state {
93 	GS_CAN_TERMINATION_STATE_OFF = 0,
94 	GS_CAN_TERMINATION_STATE_ON
95 };
96 
97 #define GS_USB_TERMINATION_DISABLED CAN_TERMINATION_DISABLED
98 #define GS_USB_TERMINATION_ENABLED 120
99 
100 /* data types passed between host and device */
101 
102 /* The firmware on the original USB2CAN by Geschwister Schneider
103  * Technologie Entwicklungs- und Vertriebs UG exchanges all data
104  * between the host and the device in host byte order. This is done
105  * with the struct gs_host_config::byte_order member, which is sent
106  * first to indicate the desired byte order.
107  *
108  * The widely used open source firmware candleLight doesn't support
109  * this feature and exchanges the data in little endian byte order.
110  */
111 struct gs_host_config {
112 	__le32 byte_order;
113 } __packed;
114 
115 struct gs_device_config {
116 	u8 reserved1;
117 	u8 reserved2;
118 	u8 reserved3;
119 	u8 icount;
120 	__le32 sw_version;
121 	__le32 hw_version;
122 } __packed;
123 
124 #define GS_CAN_MODE_NORMAL 0
125 #define GS_CAN_MODE_LISTEN_ONLY BIT(0)
126 #define GS_CAN_MODE_LOOP_BACK BIT(1)
127 #define GS_CAN_MODE_TRIPLE_SAMPLE BIT(2)
128 #define GS_CAN_MODE_ONE_SHOT BIT(3)
129 #define GS_CAN_MODE_HW_TIMESTAMP BIT(4)
130 /* GS_CAN_FEATURE_IDENTIFY BIT(5) */
131 /* GS_CAN_FEATURE_USER_ID BIT(6) */
132 #define GS_CAN_MODE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
133 #define GS_CAN_MODE_FD BIT(8)
134 /* GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9) */
135 /* GS_CAN_FEATURE_BT_CONST_EXT BIT(10) */
136 /* GS_CAN_FEATURE_TERMINATION BIT(11) */
137 
138 struct gs_device_mode {
139 	__le32 mode;
140 	__le32 flags;
141 } __packed;
142 
143 struct gs_device_state {
144 	__le32 state;
145 	__le32 rxerr;
146 	__le32 txerr;
147 } __packed;
148 
149 struct gs_device_bittiming {
150 	__le32 prop_seg;
151 	__le32 phase_seg1;
152 	__le32 phase_seg2;
153 	__le32 sjw;
154 	__le32 brp;
155 } __packed;
156 
157 struct gs_identify_mode {
158 	__le32 mode;
159 } __packed;
160 
161 struct gs_device_termination_state {
162 	__le32 state;
163 } __packed;
164 
165 #define GS_CAN_FEATURE_LISTEN_ONLY BIT(0)
166 #define GS_CAN_FEATURE_LOOP_BACK BIT(1)
167 #define GS_CAN_FEATURE_TRIPLE_SAMPLE BIT(2)
168 #define GS_CAN_FEATURE_ONE_SHOT BIT(3)
169 #define GS_CAN_FEATURE_HW_TIMESTAMP BIT(4)
170 #define GS_CAN_FEATURE_IDENTIFY BIT(5)
171 #define GS_CAN_FEATURE_USER_ID BIT(6)
172 #define GS_CAN_FEATURE_PAD_PKTS_TO_MAX_PKT_SIZE BIT(7)
173 #define GS_CAN_FEATURE_FD BIT(8)
174 #define GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX BIT(9)
175 #define GS_CAN_FEATURE_BT_CONST_EXT BIT(10)
176 #define GS_CAN_FEATURE_TERMINATION BIT(11)
177 #define GS_CAN_FEATURE_MASK GENMASK(11, 0)
178 
179 /* internal quirks - keep in GS_CAN_FEATURE space for now */
180 
181 /* CANtact Pro original firmware:
182  * BREQ DATA_BITTIMING overlaps with GET_USER_ID
183  */
184 #define GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO BIT(31)
185 
186 struct gs_device_bt_const {
187 	__le32 feature;
188 	__le32 fclk_can;
189 	__le32 tseg1_min;
190 	__le32 tseg1_max;
191 	__le32 tseg2_min;
192 	__le32 tseg2_max;
193 	__le32 sjw_max;
194 	__le32 brp_min;
195 	__le32 brp_max;
196 	__le32 brp_inc;
197 } __packed;
198 
199 struct gs_device_bt_const_extended {
200 	__le32 feature;
201 	__le32 fclk_can;
202 	__le32 tseg1_min;
203 	__le32 tseg1_max;
204 	__le32 tseg2_min;
205 	__le32 tseg2_max;
206 	__le32 sjw_max;
207 	__le32 brp_min;
208 	__le32 brp_max;
209 	__le32 brp_inc;
210 
211 	__le32 dtseg1_min;
212 	__le32 dtseg1_max;
213 	__le32 dtseg2_min;
214 	__le32 dtseg2_max;
215 	__le32 dsjw_max;
216 	__le32 dbrp_min;
217 	__le32 dbrp_max;
218 	__le32 dbrp_inc;
219 } __packed;
220 
221 #define GS_CAN_FLAG_OVERFLOW BIT(0)
222 #define GS_CAN_FLAG_FD BIT(1)
223 #define GS_CAN_FLAG_BRS BIT(2)
224 #define GS_CAN_FLAG_ESI BIT(3)
225 
226 struct classic_can {
227 	u8 data[8];
228 } __packed;
229 
230 struct classic_can_ts {
231 	u8 data[8];
232 	__le32 timestamp_us;
233 } __packed;
234 
235 struct classic_can_quirk {
236 	u8 data[8];
237 	u8 quirk;
238 } __packed;
239 
240 struct canfd {
241 	u8 data[64];
242 } __packed;
243 
244 struct canfd_ts {
245 	u8 data[64];
246 	__le32 timestamp_us;
247 } __packed;
248 
249 struct canfd_quirk {
250 	u8 data[64];
251 	u8 quirk;
252 } __packed;
253 
254 struct gs_host_frame {
255 	u32 echo_id;
256 	__le32 can_id;
257 
258 	u8 can_dlc;
259 	u8 channel;
260 	u8 flags;
261 	u8 reserved;
262 
263 	union {
264 		DECLARE_FLEX_ARRAY(struct classic_can, classic_can);
265 		DECLARE_FLEX_ARRAY(struct classic_can_ts, classic_can_ts);
266 		DECLARE_FLEX_ARRAY(struct classic_can_quirk, classic_can_quirk);
267 		DECLARE_FLEX_ARRAY(struct canfd, canfd);
268 		DECLARE_FLEX_ARRAY(struct canfd_ts, canfd_ts);
269 		DECLARE_FLEX_ARRAY(struct canfd_quirk, canfd_quirk);
270 	};
271 } __packed;
272 /* The GS USB devices make use of the same flags and masks as in
273  * linux/can.h and linux/can/error.h, and no additional mapping is necessary.
274  */
275 
276 /* Only send a max of GS_MAX_TX_URBS frames per channel at a time. */
277 #define GS_MAX_TX_URBS 10
278 /* Only launch a max of GS_MAX_RX_URBS usb requests at a time. */
279 #define GS_MAX_RX_URBS 30
280 /* Maximum number of interfaces the driver supports per device.
281  * Current hardware only supports 3 interfaces. The future may vary.
282  */
283 #define GS_MAX_INTF 3
284 
285 struct gs_tx_context {
286 	struct gs_can *dev;
287 	unsigned int echo_id;
288 };
289 
290 struct gs_can {
291 	struct can_priv can; /* must be the first member */
292 
293 	struct gs_usb *parent;
294 
295 	struct net_device *netdev;
296 	struct usb_device *udev;
297 	struct usb_interface *iface;
298 
299 	struct can_bittiming_const bt_const, data_bt_const;
300 	unsigned int channel;	/* channel number */
301 
302 	/* time counter for hardware timestamps */
303 	struct cyclecounter cc;
304 	struct timecounter tc;
305 	spinlock_t tc_lock; /* spinlock to guard access tc->cycle_last */
306 	struct delayed_work timestamp;
307 
308 	u32 feature;
309 	unsigned int hf_size_tx;
310 
311 	/* This lock prevents a race condition between xmit and receive. */
312 	spinlock_t tx_ctx_lock;
313 	struct gs_tx_context tx_context[GS_MAX_TX_URBS];
314 
315 	struct usb_anchor tx_submitted;
316 	atomic_t active_tx_urbs;
317 };
318 
319 /* usb interface struct */
320 struct gs_usb {
321 	struct gs_can *canch[GS_MAX_INTF];
322 	struct usb_anchor rx_submitted;
323 	struct usb_device *udev;
324 	unsigned int hf_size_rx;
325 	u8 active_channels;
326 };
327 
328 /* 'allocate' a tx context.
329  * returns a valid tx context or NULL if there is no space.
330  */
331 static struct gs_tx_context *gs_alloc_tx_context(struct gs_can *dev)
332 {
333 	int i = 0;
334 	unsigned long flags;
335 
336 	spin_lock_irqsave(&dev->tx_ctx_lock, flags);
337 
338 	for (; i < GS_MAX_TX_URBS; i++) {
339 		if (dev->tx_context[i].echo_id == GS_MAX_TX_URBS) {
340 			dev->tx_context[i].echo_id = i;
341 			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
342 			return &dev->tx_context[i];
343 		}
344 	}
345 
346 	spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
347 	return NULL;
348 }
349 
350 /* releases a tx context
351  */
352 static void gs_free_tx_context(struct gs_tx_context *txc)
353 {
354 	txc->echo_id = GS_MAX_TX_URBS;
355 }
356 
357 /* Get a tx context by id.
358  */
359 static struct gs_tx_context *gs_get_tx_context(struct gs_can *dev,
360 					       unsigned int id)
361 {
362 	unsigned long flags;
363 
364 	if (id < GS_MAX_TX_URBS) {
365 		spin_lock_irqsave(&dev->tx_ctx_lock, flags);
366 		if (dev->tx_context[id].echo_id == id) {
367 			spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
368 			return &dev->tx_context[id];
369 		}
370 		spin_unlock_irqrestore(&dev->tx_ctx_lock, flags);
371 	}
372 	return NULL;
373 }
374 
375 static int gs_cmd_reset(struct gs_can *dev)
376 {
377 	struct gs_device_mode dm = {
378 		.mode = GS_CAN_MODE_RESET,
379 	};
380 
381 	return usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
382 				    GS_USB_BREQ_MODE,
383 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
384 				    dev->channel, 0, &dm, sizeof(dm), 1000,
385 				    GFP_KERNEL);
386 }
387 
388 static inline int gs_usb_get_timestamp(const struct gs_can *dev,
389 				       u32 *timestamp_p)
390 {
391 	__le32 timestamp;
392 	int rc;
393 
394 	rc = usb_control_msg_recv(interface_to_usbdev(dev->iface), 0,
395 				  GS_USB_BREQ_TIMESTAMP,
396 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
397 				  dev->channel, 0,
398 				  &timestamp, sizeof(timestamp),
399 				  USB_CTRL_GET_TIMEOUT,
400 				  GFP_KERNEL);
401 	if (rc)
402 		return rc;
403 
404 	*timestamp_p = le32_to_cpu(timestamp);
405 
406 	return 0;
407 }
408 
409 static u64 gs_usb_timestamp_read(const struct cyclecounter *cc) __must_hold(&dev->tc_lock)
410 {
411 	struct gs_can *dev = container_of(cc, struct gs_can, cc);
412 	u32 timestamp = 0;
413 	int err;
414 
415 	lockdep_assert_held(&dev->tc_lock);
416 
417 	/* drop lock for synchronous USB transfer */
418 	spin_unlock_bh(&dev->tc_lock);
419 	err = gs_usb_get_timestamp(dev, &timestamp);
420 	spin_lock_bh(&dev->tc_lock);
421 	if (err)
422 		netdev_err(dev->netdev,
423 			   "Error %d while reading timestamp. HW timestamps may be inaccurate.",
424 			   err);
425 
426 	return timestamp;
427 }
428 
429 static void gs_usb_timestamp_work(struct work_struct *work)
430 {
431 	struct delayed_work *delayed_work = to_delayed_work(work);
432 	struct gs_can *dev;
433 
434 	dev = container_of(delayed_work, struct gs_can, timestamp);
435 	spin_lock_bh(&dev->tc_lock);
436 	timecounter_read(&dev->tc);
437 	spin_unlock_bh(&dev->tc_lock);
438 
439 	schedule_delayed_work(&dev->timestamp,
440 			      GS_USB_TIMESTAMP_WORK_DELAY_SEC * HZ);
441 }
442 
443 static void gs_usb_skb_set_timestamp(struct gs_can *dev,
444 				     struct sk_buff *skb, u32 timestamp)
445 {
446 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
447 	u64 ns;
448 
449 	spin_lock_bh(&dev->tc_lock);
450 	ns = timecounter_cyc2time(&dev->tc, timestamp);
451 	spin_unlock_bh(&dev->tc_lock);
452 
453 	hwtstamps->hwtstamp = ns_to_ktime(ns);
454 }
455 
456 static void gs_usb_timestamp_init(struct gs_can *dev)
457 {
458 	struct cyclecounter *cc = &dev->cc;
459 
460 	cc->read = gs_usb_timestamp_read;
461 	cc->mask = CYCLECOUNTER_MASK(32);
462 	cc->shift = 32 - bits_per(NSEC_PER_SEC / GS_USB_TIMESTAMP_TIMER_HZ);
463 	cc->mult = clocksource_hz2mult(GS_USB_TIMESTAMP_TIMER_HZ, cc->shift);
464 
465 	spin_lock_init(&dev->tc_lock);
466 	spin_lock_bh(&dev->tc_lock);
467 	timecounter_init(&dev->tc, &dev->cc, ktime_get_real_ns());
468 	spin_unlock_bh(&dev->tc_lock);
469 
470 	INIT_DELAYED_WORK(&dev->timestamp, gs_usb_timestamp_work);
471 	schedule_delayed_work(&dev->timestamp,
472 			      GS_USB_TIMESTAMP_WORK_DELAY_SEC * HZ);
473 }
474 
475 static void gs_usb_timestamp_stop(struct gs_can *dev)
476 {
477 	cancel_delayed_work_sync(&dev->timestamp);
478 }
479 
480 static void gs_update_state(struct gs_can *dev, struct can_frame *cf)
481 {
482 	struct can_device_stats *can_stats = &dev->can.can_stats;
483 
484 	if (cf->can_id & CAN_ERR_RESTARTED) {
485 		dev->can.state = CAN_STATE_ERROR_ACTIVE;
486 		can_stats->restarts++;
487 	} else if (cf->can_id & CAN_ERR_BUSOFF) {
488 		dev->can.state = CAN_STATE_BUS_OFF;
489 		can_stats->bus_off++;
490 	} else if (cf->can_id & CAN_ERR_CRTL) {
491 		if ((cf->data[1] & CAN_ERR_CRTL_TX_WARNING) ||
492 		    (cf->data[1] & CAN_ERR_CRTL_RX_WARNING)) {
493 			dev->can.state = CAN_STATE_ERROR_WARNING;
494 			can_stats->error_warning++;
495 		} else if ((cf->data[1] & CAN_ERR_CRTL_TX_PASSIVE) ||
496 			   (cf->data[1] & CAN_ERR_CRTL_RX_PASSIVE)) {
497 			dev->can.state = CAN_STATE_ERROR_PASSIVE;
498 			can_stats->error_passive++;
499 		} else {
500 			dev->can.state = CAN_STATE_ERROR_ACTIVE;
501 		}
502 	}
503 }
504 
505 static void gs_usb_set_timestamp(struct gs_can *dev, struct sk_buff *skb,
506 				 const struct gs_host_frame *hf)
507 {
508 	u32 timestamp;
509 
510 	if (!(dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP))
511 		return;
512 
513 	if (hf->flags & GS_CAN_FLAG_FD)
514 		timestamp = le32_to_cpu(hf->canfd_ts->timestamp_us);
515 	else
516 		timestamp = le32_to_cpu(hf->classic_can_ts->timestamp_us);
517 
518 	gs_usb_skb_set_timestamp(dev, skb, timestamp);
519 
520 	return;
521 }
522 
523 static void gs_usb_receive_bulk_callback(struct urb *urb)
524 {
525 	struct gs_usb *usbcan = urb->context;
526 	struct gs_can *dev;
527 	struct net_device *netdev;
528 	int rc;
529 	struct net_device_stats *stats;
530 	struct gs_host_frame *hf = urb->transfer_buffer;
531 	struct gs_tx_context *txc;
532 	struct can_frame *cf;
533 	struct canfd_frame *cfd;
534 	struct sk_buff *skb;
535 
536 	BUG_ON(!usbcan);
537 
538 	switch (urb->status) {
539 	case 0: /* success */
540 		break;
541 	case -ENOENT:
542 	case -ESHUTDOWN:
543 		return;
544 	default:
545 		/* do not resubmit aborted urbs. eg: when device goes down */
546 		return;
547 	}
548 
549 	/* device reports out of range channel id */
550 	if (hf->channel >= GS_MAX_INTF)
551 		goto device_detach;
552 
553 	dev = usbcan->canch[hf->channel];
554 
555 	netdev = dev->netdev;
556 	stats = &netdev->stats;
557 
558 	if (!netif_device_present(netdev))
559 		return;
560 
561 	if (hf->echo_id == -1) { /* normal rx */
562 		if (hf->flags & GS_CAN_FLAG_FD) {
563 			skb = alloc_canfd_skb(dev->netdev, &cfd);
564 			if (!skb)
565 				return;
566 
567 			cfd->can_id = le32_to_cpu(hf->can_id);
568 			cfd->len = can_fd_dlc2len(hf->can_dlc);
569 			if (hf->flags & GS_CAN_FLAG_BRS)
570 				cfd->flags |= CANFD_BRS;
571 			if (hf->flags & GS_CAN_FLAG_ESI)
572 				cfd->flags |= CANFD_ESI;
573 
574 			memcpy(cfd->data, hf->canfd->data, cfd->len);
575 		} else {
576 			skb = alloc_can_skb(dev->netdev, &cf);
577 			if (!skb)
578 				return;
579 
580 			cf->can_id = le32_to_cpu(hf->can_id);
581 			can_frame_set_cc_len(cf, hf->can_dlc, dev->can.ctrlmode);
582 
583 			memcpy(cf->data, hf->classic_can->data, 8);
584 
585 			/* ERROR frames tell us information about the controller */
586 			if (le32_to_cpu(hf->can_id) & CAN_ERR_FLAG)
587 				gs_update_state(dev, cf);
588 		}
589 
590 		gs_usb_set_timestamp(dev, skb, hf);
591 
592 		netdev->stats.rx_packets++;
593 		netdev->stats.rx_bytes += hf->can_dlc;
594 
595 		netif_rx(skb);
596 	} else { /* echo_id == hf->echo_id */
597 		if (hf->echo_id >= GS_MAX_TX_URBS) {
598 			netdev_err(netdev,
599 				   "Unexpected out of range echo id %u\n",
600 				   hf->echo_id);
601 			goto resubmit_urb;
602 		}
603 
604 		txc = gs_get_tx_context(dev, hf->echo_id);
605 
606 		/* bad devices send bad echo_ids. */
607 		if (!txc) {
608 			netdev_err(netdev,
609 				   "Unexpected unused echo id %u\n",
610 				   hf->echo_id);
611 			goto resubmit_urb;
612 		}
613 
614 		skb = dev->can.echo_skb[hf->echo_id];
615 		gs_usb_set_timestamp(dev, skb, hf);
616 
617 		netdev->stats.tx_packets++;
618 		netdev->stats.tx_bytes += can_get_echo_skb(netdev, hf->echo_id,
619 							   NULL);
620 
621 		gs_free_tx_context(txc);
622 
623 		atomic_dec(&dev->active_tx_urbs);
624 
625 		netif_wake_queue(netdev);
626 	}
627 
628 	if (hf->flags & GS_CAN_FLAG_OVERFLOW) {
629 		skb = alloc_can_err_skb(netdev, &cf);
630 		if (!skb)
631 			goto resubmit_urb;
632 
633 		cf->can_id |= CAN_ERR_CRTL;
634 		cf->len = CAN_ERR_DLC;
635 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
636 		stats->rx_over_errors++;
637 		stats->rx_errors++;
638 		netif_rx(skb);
639 	}
640 
641  resubmit_urb:
642 	usb_fill_bulk_urb(urb, usbcan->udev,
643 			  usb_rcvbulkpipe(usbcan->udev, GS_USB_ENDPOINT_IN),
644 			  hf, dev->parent->hf_size_rx,
645 			  gs_usb_receive_bulk_callback, usbcan);
646 
647 	rc = usb_submit_urb(urb, GFP_ATOMIC);
648 
649 	/* USB failure take down all interfaces */
650 	if (rc == -ENODEV) {
651  device_detach:
652 		for (rc = 0; rc < GS_MAX_INTF; rc++) {
653 			if (usbcan->canch[rc])
654 				netif_device_detach(usbcan->canch[rc]->netdev);
655 		}
656 	}
657 }
658 
659 static int gs_usb_set_bittiming(struct net_device *netdev)
660 {
661 	struct gs_can *dev = netdev_priv(netdev);
662 	struct can_bittiming *bt = &dev->can.bittiming;
663 	struct gs_device_bittiming dbt = {
664 		.prop_seg = cpu_to_le32(bt->prop_seg),
665 		.phase_seg1 = cpu_to_le32(bt->phase_seg1),
666 		.phase_seg2 = cpu_to_le32(bt->phase_seg2),
667 		.sjw = cpu_to_le32(bt->sjw),
668 		.brp = cpu_to_le32(bt->brp),
669 	};
670 
671 	/* request bit timings */
672 	return usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
673 				    GS_USB_BREQ_BITTIMING,
674 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
675 				    dev->channel, 0, &dbt, sizeof(dbt), 1000,
676 				    GFP_KERNEL);
677 }
678 
679 static int gs_usb_set_data_bittiming(struct net_device *netdev)
680 {
681 	struct gs_can *dev = netdev_priv(netdev);
682 	struct can_bittiming *bt = &dev->can.data_bittiming;
683 	struct gs_device_bittiming dbt = {
684 		.prop_seg = cpu_to_le32(bt->prop_seg),
685 		.phase_seg1 = cpu_to_le32(bt->phase_seg1),
686 		.phase_seg2 = cpu_to_le32(bt->phase_seg2),
687 		.sjw = cpu_to_le32(bt->sjw),
688 		.brp = cpu_to_le32(bt->brp),
689 	};
690 	u8 request = GS_USB_BREQ_DATA_BITTIMING;
691 
692 	if (dev->feature & GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO)
693 		request = GS_USB_BREQ_QUIRK_CANTACT_PRO_DATA_BITTIMING;
694 
695 	/* request data bit timings */
696 	return usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
697 				    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_dropped_invalid_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 		flags |= GS_CAN_MODE_FD;
847 
848 		if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
849 			dev->hf_size_tx = struct_size(hf, canfd_quirk, 1);
850 		else
851 			dev->hf_size_tx = struct_size(hf, canfd, 1);
852 	} else {
853 		if (dev->feature & GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX)
854 			dev->hf_size_tx = struct_size(hf, classic_can_quirk, 1);
855 		else
856 			dev->hf_size_tx = struct_size(hf, classic_can, 1);
857 	}
858 
859 	if (!parent->active_channels) {
860 		for (i = 0; i < GS_MAX_RX_URBS; i++) {
861 			struct urb *urb;
862 			u8 *buf;
863 
864 			/* alloc rx urb */
865 			urb = usb_alloc_urb(0, GFP_KERNEL);
866 			if (!urb)
867 				return -ENOMEM;
868 
869 			/* alloc rx buffer */
870 			buf = kmalloc(dev->parent->hf_size_rx,
871 				      GFP_KERNEL);
872 			if (!buf) {
873 				netdev_err(netdev,
874 					   "No memory left for USB buffer\n");
875 				usb_free_urb(urb);
876 				return -ENOMEM;
877 			}
878 
879 			/* fill, anchor, and submit rx urb */
880 			usb_fill_bulk_urb(urb,
881 					  dev->udev,
882 					  usb_rcvbulkpipe(dev->udev,
883 							  GS_USB_ENDPOINT_IN),
884 					  buf,
885 					  dev->parent->hf_size_rx,
886 					  gs_usb_receive_bulk_callback, parent);
887 			urb->transfer_flags |= URB_FREE_BUFFER;
888 
889 			usb_anchor_urb(urb, &parent->rx_submitted);
890 
891 			rc = usb_submit_urb(urb, GFP_KERNEL);
892 			if (rc) {
893 				if (rc == -ENODEV)
894 					netif_device_detach(dev->netdev);
895 
896 				netdev_err(netdev,
897 					   "usb_submit failed (err=%d)\n", rc);
898 
899 				usb_unanchor_urb(urb);
900 				usb_free_urb(urb);
901 				break;
902 			}
903 
904 			/* Drop reference,
905 			 * USB core will take care of freeing it
906 			 */
907 			usb_free_urb(urb);
908 		}
909 	}
910 
911 	/* flags */
912 	if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
913 		flags |= GS_CAN_MODE_LOOP_BACK;
914 	else if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
915 		flags |= GS_CAN_MODE_LISTEN_ONLY;
916 
917 	/* Controller is not allowed to retry TX
918 	 * this mode is unavailable on atmels uc3c hardware
919 	 */
920 	if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
921 		flags |= GS_CAN_MODE_ONE_SHOT;
922 
923 	if (ctrlmode & CAN_CTRLMODE_3_SAMPLES)
924 		flags |= GS_CAN_MODE_TRIPLE_SAMPLE;
925 
926 	/* if hardware supports timestamps, enable it */
927 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
928 		flags |= GS_CAN_MODE_HW_TIMESTAMP;
929 
930 	/* start polling timestamp */
931 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
932 		gs_usb_timestamp_init(dev);
933 
934 	/* finally start device */
935 	dev->can.state = CAN_STATE_ERROR_ACTIVE;
936 	dm.flags = cpu_to_le32(flags);
937 	rc = usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
938 				  GS_USB_BREQ_MODE,
939 				  USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
940 				  dev->channel, 0, &dm, sizeof(dm), 1000,
941 				  GFP_KERNEL);
942 	if (rc) {
943 		netdev_err(netdev, "Couldn't start device (err=%d)\n", rc);
944 		if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
945 			gs_usb_timestamp_stop(dev);
946 		dev->can.state = CAN_STATE_STOPPED;
947 		return rc;
948 	}
949 
950 	parent->active_channels++;
951 	if (!(dev->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
952 		netif_start_queue(netdev);
953 
954 	return 0;
955 }
956 
957 static int gs_can_close(struct net_device *netdev)
958 {
959 	int rc;
960 	struct gs_can *dev = netdev_priv(netdev);
961 	struct gs_usb *parent = dev->parent;
962 
963 	netif_stop_queue(netdev);
964 
965 	/* stop polling timestamp */
966 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
967 		gs_usb_timestamp_stop(dev);
968 
969 	/* Stop polling */
970 	parent->active_channels--;
971 	if (!parent->active_channels) {
972 		usb_kill_anchored_urbs(&parent->rx_submitted);
973 	}
974 
975 	/* Stop sending URBs */
976 	usb_kill_anchored_urbs(&dev->tx_submitted);
977 	atomic_set(&dev->active_tx_urbs, 0);
978 
979 	/* reset the device */
980 	rc = gs_cmd_reset(dev);
981 	if (rc < 0)
982 		netdev_warn(netdev, "Couldn't shutdown device (err=%d)", rc);
983 
984 	/* reset tx contexts */
985 	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
986 		dev->tx_context[rc].dev = dev;
987 		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
988 	}
989 
990 	/* close the netdev */
991 	close_candev(netdev);
992 
993 	return 0;
994 }
995 
996 static int gs_can_eth_ioctl(struct net_device *netdev, struct ifreq *ifr, int cmd)
997 {
998 	const struct gs_can *dev = netdev_priv(netdev);
999 
1000 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1001 		return can_eth_ioctl_hwts(netdev, ifr, cmd);
1002 
1003 	return -EOPNOTSUPP;
1004 }
1005 
1006 static const struct net_device_ops gs_usb_netdev_ops = {
1007 	.ndo_open = gs_can_open,
1008 	.ndo_stop = gs_can_close,
1009 	.ndo_start_xmit = gs_can_start_xmit,
1010 	.ndo_change_mtu = can_change_mtu,
1011 	.ndo_eth_ioctl = gs_can_eth_ioctl,
1012 };
1013 
1014 static int gs_usb_set_identify(struct net_device *netdev, bool do_identify)
1015 {
1016 	struct gs_can *dev = netdev_priv(netdev);
1017 	struct gs_identify_mode imode;
1018 
1019 	if (do_identify)
1020 		imode.mode = cpu_to_le32(GS_CAN_IDENTIFY_ON);
1021 	else
1022 		imode.mode = cpu_to_le32(GS_CAN_IDENTIFY_OFF);
1023 
1024 	return usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
1025 				    GS_USB_BREQ_IDENTIFY,
1026 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1027 				    dev->channel, 0, &imode, sizeof(imode), 100,
1028 				    GFP_KERNEL);
1029 }
1030 
1031 /* blink LED's for finding the this interface */
1032 static int gs_usb_set_phys_id(struct net_device *netdev,
1033 			      enum ethtool_phys_id_state state)
1034 {
1035 	const struct gs_can *dev = netdev_priv(netdev);
1036 	int rc = 0;
1037 
1038 	if (!(dev->feature & GS_CAN_FEATURE_IDENTIFY))
1039 		return -EOPNOTSUPP;
1040 
1041 	switch (state) {
1042 	case ETHTOOL_ID_ACTIVE:
1043 		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_ON);
1044 		break;
1045 	case ETHTOOL_ID_INACTIVE:
1046 		rc = gs_usb_set_identify(netdev, GS_CAN_IDENTIFY_OFF);
1047 		break;
1048 	default:
1049 		break;
1050 	}
1051 
1052 	return rc;
1053 }
1054 
1055 static int gs_usb_get_ts_info(struct net_device *netdev,
1056 			      struct ethtool_ts_info *info)
1057 {
1058 	struct gs_can *dev = netdev_priv(netdev);
1059 
1060 	/* report if device supports HW timestamps */
1061 	if (dev->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1062 		return can_ethtool_op_get_ts_info_hwts(netdev, info);
1063 
1064 	return ethtool_op_get_ts_info(netdev, info);
1065 }
1066 
1067 static const struct ethtool_ops gs_usb_ethtool_ops = {
1068 	.set_phys_id = gs_usb_set_phys_id,
1069 	.get_ts_info = gs_usb_get_ts_info,
1070 };
1071 
1072 static int gs_usb_get_termination(struct net_device *netdev, u16 *term)
1073 {
1074 	struct gs_can *dev = netdev_priv(netdev);
1075 	struct gs_device_termination_state term_state;
1076 	int rc;
1077 
1078 	rc = usb_control_msg_recv(interface_to_usbdev(dev->iface), 0,
1079 				  GS_USB_BREQ_GET_TERMINATION,
1080 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1081 				  dev->channel, 0,
1082 				  &term_state, sizeof(term_state), 1000,
1083 				  GFP_KERNEL);
1084 	if (rc)
1085 		return rc;
1086 
1087 	if (term_state.state == cpu_to_le32(GS_CAN_TERMINATION_STATE_ON))
1088 		*term = GS_USB_TERMINATION_ENABLED;
1089 	else
1090 		*term = GS_USB_TERMINATION_DISABLED;
1091 
1092 	return 0;
1093 }
1094 
1095 static int gs_usb_set_termination(struct net_device *netdev, u16 term)
1096 {
1097 	struct gs_can *dev = netdev_priv(netdev);
1098 	struct gs_device_termination_state term_state;
1099 
1100 	if (term == GS_USB_TERMINATION_ENABLED)
1101 		term_state.state = cpu_to_le32(GS_CAN_TERMINATION_STATE_ON);
1102 	else
1103 		term_state.state = cpu_to_le32(GS_CAN_TERMINATION_STATE_OFF);
1104 
1105 	return usb_control_msg_send(interface_to_usbdev(dev->iface), 0,
1106 				    GS_USB_BREQ_SET_TERMINATION,
1107 				    USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1108 				    dev->channel, 0,
1109 				    &term_state, sizeof(term_state), 1000,
1110 				    GFP_KERNEL);
1111 }
1112 
1113 static const u16 gs_usb_termination_const[] = {
1114 	GS_USB_TERMINATION_DISABLED,
1115 	GS_USB_TERMINATION_ENABLED
1116 };
1117 
1118 static struct gs_can *gs_make_candev(unsigned int channel,
1119 				     struct usb_interface *intf,
1120 				     struct gs_device_config *dconf)
1121 {
1122 	struct gs_can *dev;
1123 	struct net_device *netdev;
1124 	int rc;
1125 	struct gs_device_bt_const_extended bt_const_extended;
1126 	struct gs_device_bt_const bt_const;
1127 	u32 feature;
1128 
1129 	/* fetch bit timing constants */
1130 	rc = usb_control_msg_recv(interface_to_usbdev(intf), 0,
1131 				  GS_USB_BREQ_BT_CONST,
1132 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1133 				  channel, 0, &bt_const, sizeof(bt_const), 1000,
1134 				  GFP_KERNEL);
1135 
1136 	if (rc) {
1137 		dev_err(&intf->dev,
1138 			"Couldn't get bit timing const for channel %d (%pe)\n",
1139 			channel, ERR_PTR(rc));
1140 		return ERR_PTR(rc);
1141 	}
1142 
1143 	/* create netdev */
1144 	netdev = alloc_candev(sizeof(struct gs_can), GS_MAX_TX_URBS);
1145 	if (!netdev) {
1146 		dev_err(&intf->dev, "Couldn't allocate candev\n");
1147 		return ERR_PTR(-ENOMEM);
1148 	}
1149 
1150 	dev = netdev_priv(netdev);
1151 
1152 	netdev->netdev_ops = &gs_usb_netdev_ops;
1153 	netdev->ethtool_ops = &gs_usb_ethtool_ops;
1154 
1155 	netdev->flags |= IFF_ECHO; /* we support full roundtrip echo */
1156 
1157 	/* dev setup */
1158 	strcpy(dev->bt_const.name, KBUILD_MODNAME);
1159 	dev->bt_const.tseg1_min = le32_to_cpu(bt_const.tseg1_min);
1160 	dev->bt_const.tseg1_max = le32_to_cpu(bt_const.tseg1_max);
1161 	dev->bt_const.tseg2_min = le32_to_cpu(bt_const.tseg2_min);
1162 	dev->bt_const.tseg2_max = le32_to_cpu(bt_const.tseg2_max);
1163 	dev->bt_const.sjw_max = le32_to_cpu(bt_const.sjw_max);
1164 	dev->bt_const.brp_min = le32_to_cpu(bt_const.brp_min);
1165 	dev->bt_const.brp_max = le32_to_cpu(bt_const.brp_max);
1166 	dev->bt_const.brp_inc = le32_to_cpu(bt_const.brp_inc);
1167 
1168 	dev->udev = interface_to_usbdev(intf);
1169 	dev->iface = intf;
1170 	dev->netdev = netdev;
1171 	dev->channel = channel;
1172 
1173 	init_usb_anchor(&dev->tx_submitted);
1174 	atomic_set(&dev->active_tx_urbs, 0);
1175 	spin_lock_init(&dev->tx_ctx_lock);
1176 	for (rc = 0; rc < GS_MAX_TX_URBS; rc++) {
1177 		dev->tx_context[rc].dev = dev;
1178 		dev->tx_context[rc].echo_id = GS_MAX_TX_URBS;
1179 	}
1180 
1181 	/* can setup */
1182 	dev->can.state = CAN_STATE_STOPPED;
1183 	dev->can.clock.freq = le32_to_cpu(bt_const.fclk_can);
1184 	dev->can.bittiming_const = &dev->bt_const;
1185 	dev->can.do_set_bittiming = gs_usb_set_bittiming;
1186 
1187 	dev->can.ctrlmode_supported = CAN_CTRLMODE_CC_LEN8_DLC;
1188 
1189 	feature = le32_to_cpu(bt_const.feature);
1190 	dev->feature = FIELD_GET(GS_CAN_FEATURE_MASK, feature);
1191 	if (feature & GS_CAN_FEATURE_LISTEN_ONLY)
1192 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
1193 
1194 	if (feature & GS_CAN_FEATURE_LOOP_BACK)
1195 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
1196 
1197 	if (feature & GS_CAN_FEATURE_TRIPLE_SAMPLE)
1198 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
1199 
1200 	if (feature & GS_CAN_FEATURE_ONE_SHOT)
1201 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
1202 
1203 	if (feature & GS_CAN_FEATURE_FD) {
1204 		dev->can.ctrlmode_supported |= CAN_CTRLMODE_FD;
1205 		/* The data bit timing will be overwritten, if
1206 		 * GS_CAN_FEATURE_BT_CONST_EXT is set.
1207 		 */
1208 		dev->can.data_bittiming_const = &dev->bt_const;
1209 		dev->can.do_set_data_bittiming = gs_usb_set_data_bittiming;
1210 	}
1211 
1212 	if (feature & GS_CAN_FEATURE_TERMINATION) {
1213 		rc = gs_usb_get_termination(netdev, &dev->can.termination);
1214 		if (rc) {
1215 			dev->feature &= ~GS_CAN_FEATURE_TERMINATION;
1216 
1217 			dev_info(&intf->dev,
1218 				 "Disabling termination support for channel %d (%pe)\n",
1219 				 channel, ERR_PTR(rc));
1220 		} else {
1221 			dev->can.termination_const = gs_usb_termination_const;
1222 			dev->can.termination_const_cnt = ARRAY_SIZE(gs_usb_termination_const);
1223 			dev->can.do_set_termination = gs_usb_set_termination;
1224 		}
1225 	}
1226 
1227 	/* The CANtact Pro from LinkLayer Labs is based on the
1228 	 * LPC54616 µC, which is affected by the NXP LPC USB transfer
1229 	 * erratum. However, the current firmware (version 2) doesn't
1230 	 * set the GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX bit. Set the
1231 	 * feature GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX to workaround
1232 	 * this issue.
1233 	 *
1234 	 * For the GS_USB_BREQ_DATA_BITTIMING USB control message the
1235 	 * CANtact Pro firmware uses a request value, which is already
1236 	 * used by the candleLight firmware for a different purpose
1237 	 * (GS_USB_BREQ_GET_USER_ID). Set the feature
1238 	 * GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO to workaround this
1239 	 * issue.
1240 	 */
1241 	if (dev->udev->descriptor.idVendor == cpu_to_le16(USB_GS_USB_1_VENDOR_ID) &&
1242 	    dev->udev->descriptor.idProduct == cpu_to_le16(USB_GS_USB_1_PRODUCT_ID) &&
1243 	    dev->udev->manufacturer && dev->udev->product &&
1244 	    !strcmp(dev->udev->manufacturer, "LinkLayer Labs") &&
1245 	    !strcmp(dev->udev->product, "CANtact Pro") &&
1246 	    (le32_to_cpu(dconf->sw_version) <= 2))
1247 		dev->feature |= GS_CAN_FEATURE_REQ_USB_QUIRK_LPC546XX |
1248 			GS_CAN_FEATURE_QUIRK_BREQ_CANTACT_PRO;
1249 
1250 	/* GS_CAN_FEATURE_IDENTIFY is only supported for sw_version > 1 */
1251 	if (!(le32_to_cpu(dconf->sw_version) > 1 &&
1252 	      feature & GS_CAN_FEATURE_IDENTIFY))
1253 		dev->feature &= ~GS_CAN_FEATURE_IDENTIFY;
1254 
1255 	/* fetch extended bit timing constants if device has feature
1256 	 * GS_CAN_FEATURE_FD and GS_CAN_FEATURE_BT_CONST_EXT
1257 	 */
1258 	if (feature & GS_CAN_FEATURE_FD &&
1259 	    feature & GS_CAN_FEATURE_BT_CONST_EXT) {
1260 		rc = usb_control_msg_recv(interface_to_usbdev(intf), 0,
1261 					  GS_USB_BREQ_BT_CONST_EXT,
1262 					  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1263 					  channel, 0, &bt_const_extended,
1264 					  sizeof(bt_const_extended),
1265 					  1000, GFP_KERNEL);
1266 		if (rc) {
1267 			dev_err(&intf->dev,
1268 				"Couldn't get extended bit timing const for channel %d (%pe)\n",
1269 				channel, ERR_PTR(rc));
1270 			goto out_free_candev;
1271 		}
1272 
1273 		strcpy(dev->data_bt_const.name, KBUILD_MODNAME);
1274 		dev->data_bt_const.tseg1_min = le32_to_cpu(bt_const_extended.dtseg1_min);
1275 		dev->data_bt_const.tseg1_max = le32_to_cpu(bt_const_extended.dtseg1_max);
1276 		dev->data_bt_const.tseg2_min = le32_to_cpu(bt_const_extended.dtseg2_min);
1277 		dev->data_bt_const.tseg2_max = le32_to_cpu(bt_const_extended.dtseg2_max);
1278 		dev->data_bt_const.sjw_max = le32_to_cpu(bt_const_extended.dsjw_max);
1279 		dev->data_bt_const.brp_min = le32_to_cpu(bt_const_extended.dbrp_min);
1280 		dev->data_bt_const.brp_max = le32_to_cpu(bt_const_extended.dbrp_max);
1281 		dev->data_bt_const.brp_inc = le32_to_cpu(bt_const_extended.dbrp_inc);
1282 
1283 		dev->can.data_bittiming_const = &dev->data_bt_const;
1284 	}
1285 
1286 	SET_NETDEV_DEV(netdev, &intf->dev);
1287 
1288 	rc = register_candev(dev->netdev);
1289 	if (rc) {
1290 		dev_err(&intf->dev,
1291 			"Couldn't register candev for channel %d (%pe)\n",
1292 			channel, ERR_PTR(rc));
1293 		goto out_free_candev;
1294 	}
1295 
1296 	return dev;
1297 
1298  out_free_candev:
1299 	free_candev(dev->netdev);
1300 	return ERR_PTR(rc);
1301 }
1302 
1303 static void gs_destroy_candev(struct gs_can *dev)
1304 {
1305 	unregister_candev(dev->netdev);
1306 	usb_kill_anchored_urbs(&dev->tx_submitted);
1307 	free_candev(dev->netdev);
1308 }
1309 
1310 static int gs_usb_probe(struct usb_interface *intf,
1311 			const struct usb_device_id *id)
1312 {
1313 	struct usb_device *udev = interface_to_usbdev(intf);
1314 	struct gs_host_frame *hf;
1315 	struct gs_usb *dev;
1316 	struct gs_host_config hconf = {
1317 		.byte_order = cpu_to_le32(0x0000beef),
1318 	};
1319 	struct gs_device_config dconf;
1320 	unsigned int icount, i;
1321 	int rc;
1322 
1323 	/* send host config */
1324 	rc = usb_control_msg_send(udev, 0,
1325 				  GS_USB_BREQ_HOST_FORMAT,
1326 				  USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1327 				  1, intf->cur_altsetting->desc.bInterfaceNumber,
1328 				  &hconf, sizeof(hconf), 1000,
1329 				  GFP_KERNEL);
1330 	if (rc) {
1331 		dev_err(&intf->dev, "Couldn't send data format (err=%d)\n", rc);
1332 		return rc;
1333 	}
1334 
1335 	/* read device config */
1336 	rc = usb_control_msg_recv(udev, 0,
1337 				  GS_USB_BREQ_DEVICE_CONFIG,
1338 				  USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_INTERFACE,
1339 				  1, intf->cur_altsetting->desc.bInterfaceNumber,
1340 				  &dconf, sizeof(dconf), 1000,
1341 				  GFP_KERNEL);
1342 	if (rc) {
1343 		dev_err(&intf->dev, "Couldn't get device config: (err=%d)\n",
1344 			rc);
1345 		return rc;
1346 	}
1347 
1348 	icount = dconf.icount + 1;
1349 	dev_info(&intf->dev, "Configuring for %u interfaces\n", icount);
1350 
1351 	if (icount > GS_MAX_INTF) {
1352 		dev_err(&intf->dev,
1353 			"Driver cannot handle more that %u CAN interfaces\n",
1354 			GS_MAX_INTF);
1355 		return -EINVAL;
1356 	}
1357 
1358 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1359 	if (!dev)
1360 		return -ENOMEM;
1361 
1362 	init_usb_anchor(&dev->rx_submitted);
1363 
1364 	usb_set_intfdata(intf, dev);
1365 	dev->udev = udev;
1366 
1367 	for (i = 0; i < icount; i++) {
1368 		unsigned int hf_size_rx = 0;
1369 
1370 		dev->canch[i] = gs_make_candev(i, intf, &dconf);
1371 		if (IS_ERR_OR_NULL(dev->canch[i])) {
1372 			/* save error code to return later */
1373 			rc = PTR_ERR(dev->canch[i]);
1374 
1375 			/* on failure destroy previously created candevs */
1376 			icount = i;
1377 			for (i = 0; i < icount; i++)
1378 				gs_destroy_candev(dev->canch[i]);
1379 
1380 			usb_kill_anchored_urbs(&dev->rx_submitted);
1381 			kfree(dev);
1382 			return rc;
1383 		}
1384 		dev->canch[i]->parent = dev;
1385 
1386 		/* set RX packet size based on FD and if hardware
1387                 * timestamps are supported.
1388 		*/
1389 		if (dev->canch[i]->can.ctrlmode_supported & CAN_CTRLMODE_FD) {
1390 			if (dev->canch[i]->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1391 				hf_size_rx = struct_size(hf, canfd_ts, 1);
1392 			else
1393 				hf_size_rx = struct_size(hf, canfd, 1);
1394 		} else {
1395 			if (dev->canch[i]->feature & GS_CAN_FEATURE_HW_TIMESTAMP)
1396 				hf_size_rx = struct_size(hf, classic_can_ts, 1);
1397 			else
1398 				hf_size_rx = struct_size(hf, classic_can, 1);
1399 		}
1400 		dev->hf_size_rx = max(dev->hf_size_rx, hf_size_rx);
1401 	}
1402 
1403 	return 0;
1404 }
1405 
1406 static void gs_usb_disconnect(struct usb_interface *intf)
1407 {
1408 	struct gs_usb *dev = usb_get_intfdata(intf);
1409 	unsigned int i;
1410 
1411 	usb_set_intfdata(intf, NULL);
1412 
1413 	if (!dev) {
1414 		dev_err(&intf->dev, "Disconnect (nodata)\n");
1415 		return;
1416 	}
1417 
1418 	for (i = 0; i < GS_MAX_INTF; i++)
1419 		if (dev->canch[i])
1420 			gs_destroy_candev(dev->canch[i]);
1421 
1422 	usb_kill_anchored_urbs(&dev->rx_submitted);
1423 	kfree(dev);
1424 }
1425 
1426 static const struct usb_device_id gs_usb_table[] = {
1427 	{ USB_DEVICE_INTERFACE_NUMBER(USB_GS_USB_1_VENDOR_ID,
1428 				      USB_GS_USB_1_PRODUCT_ID, 0) },
1429 	{ USB_DEVICE_INTERFACE_NUMBER(USB_CANDLELIGHT_VENDOR_ID,
1430 				      USB_CANDLELIGHT_PRODUCT_ID, 0) },
1431 	{ USB_DEVICE_INTERFACE_NUMBER(USB_CES_CANEXT_FD_VENDOR_ID,
1432 				      USB_CES_CANEXT_FD_PRODUCT_ID, 0) },
1433 	{ USB_DEVICE_INTERFACE_NUMBER(USB_ABE_CANDEBUGGER_FD_VENDOR_ID,
1434 				      USB_ABE_CANDEBUGGER_FD_PRODUCT_ID, 0) },
1435 	{} /* Terminating entry */
1436 };
1437 
1438 MODULE_DEVICE_TABLE(usb, gs_usb_table);
1439 
1440 static struct usb_driver gs_usb_driver = {
1441 	.name = KBUILD_MODNAME,
1442 	.probe = gs_usb_probe,
1443 	.disconnect = gs_usb_disconnect,
1444 	.id_table = gs_usb_table,
1445 };
1446 
1447 module_usb_driver(gs_usb_driver);
1448 
1449 MODULE_AUTHOR("Maximilian Schneider <mws@schneidersoft.net>");
1450 MODULE_DESCRIPTION(
1451 "Socket CAN device driver for Geschwister Schneider Technologie-, "
1452 "Entwicklungs- und Vertriebs UG. USB2.0 to CAN interfaces\n"
1453 "and bytewerk.org candleLight USB CAN interfaces.");
1454 MODULE_LICENSE("GPL v2");
1455