xref: /linux/drivers/net/can/usb/esd_usb.c (revision 3e5c291c7942d0909a48bc5ec1b9bba136465166)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CAN driver for esd electronics gmbh CAN-USB/2 and CAN-USB/Micro
4  *
5  * Copyright (C) 2010-2012 esd electronic system design gmbh, Matthias Fuchs <socketcan@esd.eu>
6  * Copyright (C) 2022 esd electronics gmbh, Frank Jungclaus <frank.jungclaus@esd.eu>
7  */
8 #include <linux/signal.h>
9 #include <linux/slab.h>
10 #include <linux/module.h>
11 #include <linux/netdevice.h>
12 #include <linux/usb.h>
13 
14 #include <linux/can.h>
15 #include <linux/can/dev.h>
16 #include <linux/can/error.h>
17 
18 MODULE_AUTHOR("Matthias Fuchs <socketcan@esd.eu>");
19 MODULE_AUTHOR("Frank Jungclaus <frank.jungclaus@esd.eu>");
20 MODULE_DESCRIPTION("CAN driver for esd electronics gmbh CAN-USB/2 and CAN-USB/Micro interfaces");
21 MODULE_LICENSE("GPL v2");
22 
23 /* USB vendor and product ID */
24 #define USB_ESDGMBH_VENDOR_ID	0x0ab4
25 #define USB_CANUSB2_PRODUCT_ID	0x0010
26 #define USB_CANUSBM_PRODUCT_ID	0x0011
27 
28 /* CAN controller clock frequencies */
29 #define ESD_USB2_CAN_CLOCK	60000000
30 #define ESD_USBM_CAN_CLOCK	36000000
31 
32 /* Maximum number of CAN nets */
33 #define ESD_USB_MAX_NETS	2
34 
35 /* USB commands */
36 #define CMD_VERSION		1 /* also used for VERSION_REPLY */
37 #define CMD_CAN_RX		2 /* device to host only */
38 #define CMD_CAN_TX		3 /* also used for TX_DONE */
39 #define CMD_SETBAUD		4 /* also used for SETBAUD_REPLY */
40 #define CMD_TS			5 /* also used for TS_REPLY */
41 #define CMD_IDADD		6 /* also used for IDADD_REPLY */
42 
43 /* esd CAN message flags - dlc field */
44 #define ESD_RTR			0x10
45 
46 /* esd CAN message flags - id field */
47 #define ESD_EXTID		0x20000000
48 #define ESD_EVENT		0x40000000
49 #define ESD_IDMASK		0x1fffffff
50 
51 /* esd CAN event ids */
52 #define ESD_EV_CAN_ERROR_EXT	2 /* CAN controller specific diagnostic data */
53 
54 /* baudrate message flags */
55 #define ESD_USB_UBR		0x80000000
56 #define ESD_USB_LOM		0x40000000
57 #define ESD_USB_NO_BAUDRATE	0x7fffffff
58 
59 /* bit timing CAN-USB/2 */
60 #define ESD_USB2_TSEG1_MIN	1
61 #define ESD_USB2_TSEG1_MAX	16
62 #define ESD_USB2_TSEG1_SHIFT	16
63 #define ESD_USB2_TSEG2_MIN	1
64 #define ESD_USB2_TSEG2_MAX	8
65 #define ESD_USB2_TSEG2_SHIFT	20
66 #define ESD_USB2_SJW_MAX	4
67 #define ESD_USB2_SJW_SHIFT	14
68 #define ESD_USBM_SJW_SHIFT	24
69 #define ESD_USB2_BRP_MIN	1
70 #define ESD_USB2_BRP_MAX	1024
71 #define ESD_USB2_BRP_INC	1
72 #define ESD_USB2_3_SAMPLES	0x00800000
73 
74 /* esd IDADD message */
75 #define ESD_ID_ENABLE		0x80
76 #define ESD_MAX_ID_SEGMENT	64
77 
78 /* SJA1000 ECC register (emulated by usb firmware) */
79 #define SJA1000_ECC_SEG		0x1F
80 #define SJA1000_ECC_DIR		0x20
81 #define SJA1000_ECC_ERR		0x06
82 #define SJA1000_ECC_BIT		0x00
83 #define SJA1000_ECC_FORM	0x40
84 #define SJA1000_ECC_STUFF	0x80
85 #define SJA1000_ECC_MASK	0xc0
86 
87 /* esd bus state event codes */
88 #define ESD_BUSSTATE_MASK	0xc0
89 #define ESD_BUSSTATE_WARN	0x40
90 #define ESD_BUSSTATE_ERRPASSIVE	0x80
91 #define ESD_BUSSTATE_BUSOFF	0xc0
92 
93 #define RX_BUFFER_SIZE		1024
94 #define MAX_RX_URBS		4
95 #define MAX_TX_URBS		16 /* must be power of 2 */
96 
97 struct header_msg {
98 	u8 len; /* len is always the total message length in 32bit words */
99 	u8 cmd;
100 	u8 rsvd[2];
101 };
102 
103 struct version_msg {
104 	u8 len;
105 	u8 cmd;
106 	u8 rsvd;
107 	u8 flags;
108 	__le32 drv_version;
109 };
110 
111 struct version_reply_msg {
112 	u8 len;
113 	u8 cmd;
114 	u8 nets;
115 	u8 features;
116 	__le32 version;
117 	u8 name[16];
118 	__le32 rsvd;
119 	__le32 ts;
120 };
121 
122 struct rx_msg {
123 	u8 len;
124 	u8 cmd;
125 	u8 net;
126 	u8 dlc;
127 	__le32 ts;
128 	__le32 id; /* upper 3 bits contain flags */
129 	u8 data[8];
130 };
131 
132 struct tx_msg {
133 	u8 len;
134 	u8 cmd;
135 	u8 net;
136 	u8 dlc;
137 	u32 hnd;	/* opaque handle, not used by device */
138 	__le32 id; /* upper 3 bits contain flags */
139 	u8 data[8];
140 };
141 
142 struct tx_done_msg {
143 	u8 len;
144 	u8 cmd;
145 	u8 net;
146 	u8 status;
147 	u32 hnd;	/* opaque handle, not used by device */
148 	__le32 ts;
149 };
150 
151 struct id_filter_msg {
152 	u8 len;
153 	u8 cmd;
154 	u8 net;
155 	u8 option;
156 	__le32 mask[ESD_MAX_ID_SEGMENT + 1];
157 };
158 
159 struct set_baudrate_msg {
160 	u8 len;
161 	u8 cmd;
162 	u8 net;
163 	u8 rsvd;
164 	__le32 baud;
165 };
166 
167 /* Main message type used between library and application */
168 struct __packed esd_usb_msg {
169 	union {
170 		struct header_msg hdr;
171 		struct version_msg version;
172 		struct version_reply_msg version_reply;
173 		struct rx_msg rx;
174 		struct tx_msg tx;
175 		struct tx_done_msg txdone;
176 		struct set_baudrate_msg setbaud;
177 		struct id_filter_msg filter;
178 	} msg;
179 };
180 
181 static struct usb_device_id esd_usb_table[] = {
182 	{USB_DEVICE(USB_ESDGMBH_VENDOR_ID, USB_CANUSB2_PRODUCT_ID)},
183 	{USB_DEVICE(USB_ESDGMBH_VENDOR_ID, USB_CANUSBM_PRODUCT_ID)},
184 	{}
185 };
186 MODULE_DEVICE_TABLE(usb, esd_usb_table);
187 
188 struct esd_usb_net_priv;
189 
190 struct esd_tx_urb_context {
191 	struct esd_usb_net_priv *priv;
192 	u32 echo_index;
193 };
194 
195 struct esd_usb {
196 	struct usb_device *udev;
197 	struct esd_usb_net_priv *nets[ESD_USB_MAX_NETS];
198 
199 	struct usb_anchor rx_submitted;
200 
201 	int net_count;
202 	u32 version;
203 	int rxinitdone;
204 	void *rxbuf[MAX_RX_URBS];
205 	dma_addr_t rxbuf_dma[MAX_RX_URBS];
206 };
207 
208 struct esd_usb_net_priv {
209 	struct can_priv can; /* must be the first member */
210 
211 	atomic_t active_tx_jobs;
212 	struct usb_anchor tx_submitted;
213 	struct esd_tx_urb_context tx_contexts[MAX_TX_URBS];
214 
215 	struct esd_usb *usb;
216 	struct net_device *netdev;
217 	int index;
218 	u8 old_state;
219 	struct can_berr_counter bec;
220 };
221 
222 static void esd_usb_rx_event(struct esd_usb_net_priv *priv,
223 			     struct esd_usb_msg *msg)
224 {
225 	struct net_device_stats *stats = &priv->netdev->stats;
226 	struct can_frame *cf;
227 	struct sk_buff *skb;
228 	u32 id = le32_to_cpu(msg->msg.rx.id) & ESD_IDMASK;
229 
230 	if (id == ESD_EV_CAN_ERROR_EXT) {
231 		u8 state = msg->msg.rx.data[0];
232 		u8 ecc = msg->msg.rx.data[1];
233 		u8 rxerr = msg->msg.rx.data[2];
234 		u8 txerr = msg->msg.rx.data[3];
235 
236 		skb = alloc_can_err_skb(priv->netdev, &cf);
237 		if (skb == NULL) {
238 			stats->rx_dropped++;
239 			return;
240 		}
241 
242 		if (state != priv->old_state) {
243 			priv->old_state = state;
244 
245 			switch (state & ESD_BUSSTATE_MASK) {
246 			case ESD_BUSSTATE_BUSOFF:
247 				priv->can.state = CAN_STATE_BUS_OFF;
248 				cf->can_id |= CAN_ERR_BUSOFF;
249 				priv->can.can_stats.bus_off++;
250 				can_bus_off(priv->netdev);
251 				break;
252 			case ESD_BUSSTATE_WARN:
253 				priv->can.state = CAN_STATE_ERROR_WARNING;
254 				priv->can.can_stats.error_warning++;
255 				break;
256 			case ESD_BUSSTATE_ERRPASSIVE:
257 				priv->can.state = CAN_STATE_ERROR_PASSIVE;
258 				priv->can.can_stats.error_passive++;
259 				break;
260 			default:
261 				priv->can.state = CAN_STATE_ERROR_ACTIVE;
262 				break;
263 			}
264 		} else {
265 			priv->can.can_stats.bus_error++;
266 			stats->rx_errors++;
267 
268 			cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR |
269 				      CAN_ERR_CNT;
270 
271 			switch (ecc & SJA1000_ECC_MASK) {
272 			case SJA1000_ECC_BIT:
273 				cf->data[2] |= CAN_ERR_PROT_BIT;
274 				break;
275 			case SJA1000_ECC_FORM:
276 				cf->data[2] |= CAN_ERR_PROT_FORM;
277 				break;
278 			case SJA1000_ECC_STUFF:
279 				cf->data[2] |= CAN_ERR_PROT_STUFF;
280 				break;
281 			default:
282 				cf->data[3] = ecc & SJA1000_ECC_SEG;
283 				break;
284 			}
285 
286 			/* Error occurred during transmission? */
287 			if (!(ecc & SJA1000_ECC_DIR))
288 				cf->data[2] |= CAN_ERR_PROT_TX;
289 
290 			if (priv->can.state == CAN_STATE_ERROR_WARNING ||
291 			    priv->can.state == CAN_STATE_ERROR_PASSIVE) {
292 				cf->data[1] = (txerr > rxerr) ?
293 					CAN_ERR_CRTL_TX_PASSIVE :
294 					CAN_ERR_CRTL_RX_PASSIVE;
295 			}
296 			cf->data[6] = txerr;
297 			cf->data[7] = rxerr;
298 		}
299 
300 		priv->bec.txerr = txerr;
301 		priv->bec.rxerr = rxerr;
302 
303 		netif_rx(skb);
304 	}
305 }
306 
307 static void esd_usb_rx_can_msg(struct esd_usb_net_priv *priv,
308 			       struct esd_usb_msg *msg)
309 {
310 	struct net_device_stats *stats = &priv->netdev->stats;
311 	struct can_frame *cf;
312 	struct sk_buff *skb;
313 	int i;
314 	u32 id;
315 
316 	if (!netif_device_present(priv->netdev))
317 		return;
318 
319 	id = le32_to_cpu(msg->msg.rx.id);
320 
321 	if (id & ESD_EVENT) {
322 		esd_usb_rx_event(priv, msg);
323 	} else {
324 		skb = alloc_can_skb(priv->netdev, &cf);
325 		if (skb == NULL) {
326 			stats->rx_dropped++;
327 			return;
328 		}
329 
330 		cf->can_id = id & ESD_IDMASK;
331 		can_frame_set_cc_len(cf, msg->msg.rx.dlc & ~ESD_RTR,
332 				     priv->can.ctrlmode);
333 
334 		if (id & ESD_EXTID)
335 			cf->can_id |= CAN_EFF_FLAG;
336 
337 		if (msg->msg.rx.dlc & ESD_RTR) {
338 			cf->can_id |= CAN_RTR_FLAG;
339 		} else {
340 			for (i = 0; i < cf->len; i++)
341 				cf->data[i] = msg->msg.rx.data[i];
342 
343 			stats->rx_bytes += cf->len;
344 		}
345 		stats->rx_packets++;
346 
347 		netif_rx(skb);
348 	}
349 }
350 
351 static void esd_usb_tx_done_msg(struct esd_usb_net_priv *priv,
352 				struct esd_usb_msg *msg)
353 {
354 	struct net_device_stats *stats = &priv->netdev->stats;
355 	struct net_device *netdev = priv->netdev;
356 	struct esd_tx_urb_context *context;
357 
358 	if (!netif_device_present(netdev))
359 		return;
360 
361 	context = &priv->tx_contexts[msg->msg.txdone.hnd & (MAX_TX_URBS - 1)];
362 
363 	if (!msg->msg.txdone.status) {
364 		stats->tx_packets++;
365 		stats->tx_bytes += can_get_echo_skb(netdev, context->echo_index,
366 						    NULL);
367 	} else {
368 		stats->tx_errors++;
369 		can_free_echo_skb(netdev, context->echo_index, NULL);
370 	}
371 
372 	/* Release context */
373 	context->echo_index = MAX_TX_URBS;
374 	atomic_dec(&priv->active_tx_jobs);
375 
376 	netif_wake_queue(netdev);
377 }
378 
379 static void esd_usb_read_bulk_callback(struct urb *urb)
380 {
381 	struct esd_usb *dev = urb->context;
382 	int retval;
383 	int pos = 0;
384 	int i;
385 
386 	switch (urb->status) {
387 	case 0: /* success */
388 		break;
389 
390 	case -ENOENT:
391 	case -EPIPE:
392 	case -EPROTO:
393 	case -ESHUTDOWN:
394 		return;
395 
396 	default:
397 		dev_info(dev->udev->dev.parent,
398 			 "Rx URB aborted (%d)\n", urb->status);
399 		goto resubmit_urb;
400 	}
401 
402 	while (pos < urb->actual_length) {
403 		struct esd_usb_msg *msg;
404 
405 		msg = (struct esd_usb_msg *)(urb->transfer_buffer + pos);
406 
407 		switch (msg->msg.hdr.cmd) {
408 		case CMD_CAN_RX:
409 			if (msg->msg.rx.net >= dev->net_count) {
410 				dev_err(dev->udev->dev.parent, "format error\n");
411 				break;
412 			}
413 
414 			esd_usb_rx_can_msg(dev->nets[msg->msg.rx.net], msg);
415 			break;
416 
417 		case CMD_CAN_TX:
418 			if (msg->msg.txdone.net >= dev->net_count) {
419 				dev_err(dev->udev->dev.parent, "format error\n");
420 				break;
421 			}
422 
423 			esd_usb_tx_done_msg(dev->nets[msg->msg.txdone.net],
424 					    msg);
425 			break;
426 		}
427 
428 		pos += msg->msg.hdr.len << 2;
429 
430 		if (pos > urb->actual_length) {
431 			dev_err(dev->udev->dev.parent, "format error\n");
432 			break;
433 		}
434 	}
435 
436 resubmit_urb:
437 	usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 1),
438 			  urb->transfer_buffer, RX_BUFFER_SIZE,
439 			  esd_usb_read_bulk_callback, dev);
440 
441 	retval = usb_submit_urb(urb, GFP_ATOMIC);
442 	if (retval == -ENODEV) {
443 		for (i = 0; i < dev->net_count; i++) {
444 			if (dev->nets[i])
445 				netif_device_detach(dev->nets[i]->netdev);
446 		}
447 	} else if (retval) {
448 		dev_err(dev->udev->dev.parent,
449 			"failed resubmitting read bulk urb: %d\n", retval);
450 	}
451 }
452 
453 /* callback for bulk IN urb */
454 static void esd_usb_write_bulk_callback(struct urb *urb)
455 {
456 	struct esd_tx_urb_context *context = urb->context;
457 	struct esd_usb_net_priv *priv;
458 	struct net_device *netdev;
459 	size_t size = sizeof(struct esd_usb_msg);
460 
461 	WARN_ON(!context);
462 
463 	priv = context->priv;
464 	netdev = priv->netdev;
465 
466 	/* free up our allocated buffer */
467 	usb_free_coherent(urb->dev, size,
468 			  urb->transfer_buffer, urb->transfer_dma);
469 
470 	if (!netif_device_present(netdev))
471 		return;
472 
473 	if (urb->status)
474 		netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
475 
476 	netif_trans_update(netdev);
477 }
478 
479 static ssize_t firmware_show(struct device *d,
480 			     struct device_attribute *attr, char *buf)
481 {
482 	struct usb_interface *intf = to_usb_interface(d);
483 	struct esd_usb *dev = usb_get_intfdata(intf);
484 
485 	return sprintf(buf, "%d.%d.%d\n",
486 		       (dev->version >> 12) & 0xf,
487 		       (dev->version >> 8) & 0xf,
488 		       dev->version & 0xff);
489 }
490 static DEVICE_ATTR_RO(firmware);
491 
492 static ssize_t hardware_show(struct device *d,
493 			     struct device_attribute *attr, char *buf)
494 {
495 	struct usb_interface *intf = to_usb_interface(d);
496 	struct esd_usb *dev = usb_get_intfdata(intf);
497 
498 	return sprintf(buf, "%d.%d.%d\n",
499 		       (dev->version >> 28) & 0xf,
500 		       (dev->version >> 24) & 0xf,
501 		       (dev->version >> 16) & 0xff);
502 }
503 static DEVICE_ATTR_RO(hardware);
504 
505 static ssize_t nets_show(struct device *d,
506 			 struct device_attribute *attr, char *buf)
507 {
508 	struct usb_interface *intf = to_usb_interface(d);
509 	struct esd_usb *dev = usb_get_intfdata(intf);
510 
511 	return sprintf(buf, "%d", dev->net_count);
512 }
513 static DEVICE_ATTR_RO(nets);
514 
515 static int esd_usb_send_msg(struct esd_usb *dev, struct esd_usb_msg *msg)
516 {
517 	int actual_length;
518 
519 	return usb_bulk_msg(dev->udev,
520 			    usb_sndbulkpipe(dev->udev, 2),
521 			    msg,
522 			    msg->msg.hdr.len << 2,
523 			    &actual_length,
524 			    1000);
525 }
526 
527 static int esd_usb_wait_msg(struct esd_usb *dev,
528 			    struct esd_usb_msg *msg)
529 {
530 	int actual_length;
531 
532 	return usb_bulk_msg(dev->udev,
533 			    usb_rcvbulkpipe(dev->udev, 1),
534 			    msg,
535 			    sizeof(*msg),
536 			    &actual_length,
537 			    1000);
538 }
539 
540 static int esd_usb_setup_rx_urbs(struct esd_usb *dev)
541 {
542 	int i, err = 0;
543 
544 	if (dev->rxinitdone)
545 		return 0;
546 
547 	for (i = 0; i < MAX_RX_URBS; i++) {
548 		struct urb *urb = NULL;
549 		u8 *buf = NULL;
550 		dma_addr_t buf_dma;
551 
552 		/* create a URB, and a buffer for it */
553 		urb = usb_alloc_urb(0, GFP_KERNEL);
554 		if (!urb) {
555 			err = -ENOMEM;
556 			break;
557 		}
558 
559 		buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
560 					 &buf_dma);
561 		if (!buf) {
562 			dev_warn(dev->udev->dev.parent,
563 				 "No memory left for USB buffer\n");
564 			err = -ENOMEM;
565 			goto freeurb;
566 		}
567 
568 		urb->transfer_dma = buf_dma;
569 
570 		usb_fill_bulk_urb(urb, dev->udev,
571 				  usb_rcvbulkpipe(dev->udev, 1),
572 				  buf, RX_BUFFER_SIZE,
573 				  esd_usb_read_bulk_callback, dev);
574 		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
575 		usb_anchor_urb(urb, &dev->rx_submitted);
576 
577 		err = usb_submit_urb(urb, GFP_KERNEL);
578 		if (err) {
579 			usb_unanchor_urb(urb);
580 			usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
581 					  urb->transfer_dma);
582 			goto freeurb;
583 		}
584 
585 		dev->rxbuf[i] = buf;
586 		dev->rxbuf_dma[i] = buf_dma;
587 
588 freeurb:
589 		/* Drop reference, USB core will take care of freeing it */
590 		usb_free_urb(urb);
591 		if (err)
592 			break;
593 	}
594 
595 	/* Did we submit any URBs */
596 	if (i == 0) {
597 		dev_err(dev->udev->dev.parent, "couldn't setup read URBs\n");
598 		return err;
599 	}
600 
601 	/* Warn if we've couldn't transmit all the URBs */
602 	if (i < MAX_RX_URBS) {
603 		dev_warn(dev->udev->dev.parent,
604 			 "rx performance may be slow\n");
605 	}
606 
607 	dev->rxinitdone = 1;
608 	return 0;
609 }
610 
611 /* Start interface */
612 static int esd_usb_start(struct esd_usb_net_priv *priv)
613 {
614 	struct esd_usb *dev = priv->usb;
615 	struct net_device *netdev = priv->netdev;
616 	struct esd_usb_msg *msg;
617 	int err, i;
618 
619 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
620 	if (!msg) {
621 		err = -ENOMEM;
622 		goto out;
623 	}
624 
625 	/* Enable all IDs
626 	 * The IDADD message takes up to 64 32 bit bitmasks (2048 bits).
627 	 * Each bit represents one 11 bit CAN identifier. A set bit
628 	 * enables reception of the corresponding CAN identifier. A cleared
629 	 * bit disabled this identifier. An additional bitmask value
630 	 * following the CAN 2.0A bits is used to enable reception of
631 	 * extended CAN frames. Only the LSB of this final mask is checked
632 	 * for the complete 29 bit ID range. The IDADD message also allows
633 	 * filter configuration for an ID subset. In this case you can add
634 	 * the number of the starting bitmask (0..64) to the filter.option
635 	 * field followed by only some bitmasks.
636 	 */
637 	msg->msg.hdr.cmd = CMD_IDADD;
638 	msg->msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
639 	msg->msg.filter.net = priv->index;
640 	msg->msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
641 	for (i = 0; i < ESD_MAX_ID_SEGMENT; i++)
642 		msg->msg.filter.mask[i] = cpu_to_le32(0xffffffff);
643 	/* enable 29bit extended IDs */
644 	msg->msg.filter.mask[ESD_MAX_ID_SEGMENT] = cpu_to_le32(0x00000001);
645 
646 	err = esd_usb_send_msg(dev, msg);
647 	if (err)
648 		goto out;
649 
650 	err = esd_usb_setup_rx_urbs(dev);
651 	if (err)
652 		goto out;
653 
654 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
655 
656 out:
657 	if (err == -ENODEV)
658 		netif_device_detach(netdev);
659 	if (err)
660 		netdev_err(netdev, "couldn't start device: %d\n", err);
661 
662 	kfree(msg);
663 	return err;
664 }
665 
666 static void unlink_all_urbs(struct esd_usb *dev)
667 {
668 	struct esd_usb_net_priv *priv;
669 	int i, j;
670 
671 	usb_kill_anchored_urbs(&dev->rx_submitted);
672 
673 	for (i = 0; i < MAX_RX_URBS; ++i)
674 		usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
675 				  dev->rxbuf[i], dev->rxbuf_dma[i]);
676 
677 	for (i = 0; i < dev->net_count; i++) {
678 		priv = dev->nets[i];
679 		if (priv) {
680 			usb_kill_anchored_urbs(&priv->tx_submitted);
681 			atomic_set(&priv->active_tx_jobs, 0);
682 
683 			for (j = 0; j < MAX_TX_URBS; j++)
684 				priv->tx_contexts[j].echo_index = MAX_TX_URBS;
685 		}
686 	}
687 }
688 
689 static int esd_usb_open(struct net_device *netdev)
690 {
691 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
692 	int err;
693 
694 	/* common open */
695 	err = open_candev(netdev);
696 	if (err)
697 		return err;
698 
699 	/* finally start device */
700 	err = esd_usb_start(priv);
701 	if (err) {
702 		netdev_warn(netdev, "couldn't start device: %d\n", err);
703 		close_candev(netdev);
704 		return err;
705 	}
706 
707 	netif_start_queue(netdev);
708 
709 	return 0;
710 }
711 
712 static netdev_tx_t esd_usb_start_xmit(struct sk_buff *skb,
713 				      struct net_device *netdev)
714 {
715 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
716 	struct esd_usb *dev = priv->usb;
717 	struct esd_tx_urb_context *context = NULL;
718 	struct net_device_stats *stats = &netdev->stats;
719 	struct can_frame *cf = (struct can_frame *)skb->data;
720 	struct esd_usb_msg *msg;
721 	struct urb *urb;
722 	u8 *buf;
723 	int i, err;
724 	int ret = NETDEV_TX_OK;
725 	size_t size = sizeof(struct esd_usb_msg);
726 
727 	if (can_dropped_invalid_skb(netdev, skb))
728 		return NETDEV_TX_OK;
729 
730 	/* create a URB, and a buffer for it, and copy the data to the URB */
731 	urb = usb_alloc_urb(0, GFP_ATOMIC);
732 	if (!urb) {
733 		stats->tx_dropped++;
734 		dev_kfree_skb(skb);
735 		goto nourbmem;
736 	}
737 
738 	buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC,
739 				 &urb->transfer_dma);
740 	if (!buf) {
741 		netdev_err(netdev, "No memory left for USB buffer\n");
742 		stats->tx_dropped++;
743 		dev_kfree_skb(skb);
744 		goto nobufmem;
745 	}
746 
747 	msg = (struct esd_usb_msg *)buf;
748 
749 	msg->msg.hdr.len = 3; /* minimal length */
750 	msg->msg.hdr.cmd = CMD_CAN_TX;
751 	msg->msg.tx.net = priv->index;
752 	msg->msg.tx.dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
753 	msg->msg.tx.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
754 
755 	if (cf->can_id & CAN_RTR_FLAG)
756 		msg->msg.tx.dlc |= ESD_RTR;
757 
758 	if (cf->can_id & CAN_EFF_FLAG)
759 		msg->msg.tx.id |= cpu_to_le32(ESD_EXTID);
760 
761 	for (i = 0; i < cf->len; i++)
762 		msg->msg.tx.data[i] = cf->data[i];
763 
764 	msg->msg.hdr.len += (cf->len + 3) >> 2;
765 
766 	for (i = 0; i < MAX_TX_URBS; i++) {
767 		if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
768 			context = &priv->tx_contexts[i];
769 			break;
770 		}
771 	}
772 
773 	/* This may never happen */
774 	if (!context) {
775 		netdev_warn(netdev, "couldn't find free context\n");
776 		ret = NETDEV_TX_BUSY;
777 		goto releasebuf;
778 	}
779 
780 	context->priv = priv;
781 	context->echo_index = i;
782 
783 	/* hnd must not be 0 - MSB is stripped in txdone handling */
784 	msg->msg.tx.hnd = 0x80000000 | i; /* returned in TX done message */
785 
786 	usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
787 			  msg->msg.hdr.len << 2,
788 			  esd_usb_write_bulk_callback, context);
789 
790 	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
791 
792 	usb_anchor_urb(urb, &priv->tx_submitted);
793 
794 	can_put_echo_skb(skb, netdev, context->echo_index, 0);
795 
796 	atomic_inc(&priv->active_tx_jobs);
797 
798 	/* Slow down tx path */
799 	if (atomic_read(&priv->active_tx_jobs) >= MAX_TX_URBS)
800 		netif_stop_queue(netdev);
801 
802 	err = usb_submit_urb(urb, GFP_ATOMIC);
803 	if (err) {
804 		can_free_echo_skb(netdev, context->echo_index, NULL);
805 
806 		atomic_dec(&priv->active_tx_jobs);
807 		usb_unanchor_urb(urb);
808 
809 		stats->tx_dropped++;
810 
811 		if (err == -ENODEV)
812 			netif_device_detach(netdev);
813 		else
814 			netdev_warn(netdev, "failed tx_urb %d\n", err);
815 
816 		goto releasebuf;
817 	}
818 
819 	netif_trans_update(netdev);
820 
821 	/* Release our reference to this URB, the USB core will eventually free
822 	 * it entirely.
823 	 */
824 	usb_free_urb(urb);
825 
826 	return NETDEV_TX_OK;
827 
828 releasebuf:
829 	usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
830 
831 nobufmem:
832 	usb_free_urb(urb);
833 
834 nourbmem:
835 	return ret;
836 }
837 
838 static int esd_usb_close(struct net_device *netdev)
839 {
840 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
841 	struct esd_usb_msg *msg;
842 	int i;
843 
844 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
845 	if (!msg)
846 		return -ENOMEM;
847 
848 	/* Disable all IDs (see esd_usb_start()) */
849 	msg->msg.hdr.cmd = CMD_IDADD;
850 	msg->msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
851 	msg->msg.filter.net = priv->index;
852 	msg->msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
853 	for (i = 0; i <= ESD_MAX_ID_SEGMENT; i++)
854 		msg->msg.filter.mask[i] = 0;
855 	if (esd_usb_send_msg(priv->usb, msg) < 0)
856 		netdev_err(netdev, "sending idadd message failed\n");
857 
858 	/* set CAN controller to reset mode */
859 	msg->msg.hdr.len = 2;
860 	msg->msg.hdr.cmd = CMD_SETBAUD;
861 	msg->msg.setbaud.net = priv->index;
862 	msg->msg.setbaud.rsvd = 0;
863 	msg->msg.setbaud.baud = cpu_to_le32(ESD_USB_NO_BAUDRATE);
864 	if (esd_usb_send_msg(priv->usb, msg) < 0)
865 		netdev_err(netdev, "sending setbaud message failed\n");
866 
867 	priv->can.state = CAN_STATE_STOPPED;
868 
869 	netif_stop_queue(netdev);
870 
871 	close_candev(netdev);
872 
873 	kfree(msg);
874 
875 	return 0;
876 }
877 
878 static const struct net_device_ops esd_usb_netdev_ops = {
879 	.ndo_open = esd_usb_open,
880 	.ndo_stop = esd_usb_close,
881 	.ndo_start_xmit = esd_usb_start_xmit,
882 	.ndo_change_mtu = can_change_mtu,
883 };
884 
885 static const struct can_bittiming_const esd_usb2_bittiming_const = {
886 	.name = "esd_usb2",
887 	.tseg1_min = ESD_USB2_TSEG1_MIN,
888 	.tseg1_max = ESD_USB2_TSEG1_MAX,
889 	.tseg2_min = ESD_USB2_TSEG2_MIN,
890 	.tseg2_max = ESD_USB2_TSEG2_MAX,
891 	.sjw_max = ESD_USB2_SJW_MAX,
892 	.brp_min = ESD_USB2_BRP_MIN,
893 	.brp_max = ESD_USB2_BRP_MAX,
894 	.brp_inc = ESD_USB2_BRP_INC,
895 };
896 
897 static int esd_usb2_set_bittiming(struct net_device *netdev)
898 {
899 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
900 	struct can_bittiming *bt = &priv->can.bittiming;
901 	struct esd_usb_msg *msg;
902 	int err;
903 	u32 canbtr;
904 	int sjw_shift;
905 
906 	canbtr = ESD_USB_UBR;
907 	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
908 		canbtr |= ESD_USB_LOM;
909 
910 	canbtr |= (bt->brp - 1) & (ESD_USB2_BRP_MAX - 1);
911 
912 	if (le16_to_cpu(priv->usb->udev->descriptor.idProduct) ==
913 	    USB_CANUSBM_PRODUCT_ID)
914 		sjw_shift = ESD_USBM_SJW_SHIFT;
915 	else
916 		sjw_shift = ESD_USB2_SJW_SHIFT;
917 
918 	canbtr |= ((bt->sjw - 1) & (ESD_USB2_SJW_MAX - 1))
919 		<< sjw_shift;
920 	canbtr |= ((bt->prop_seg + bt->phase_seg1 - 1)
921 		   & (ESD_USB2_TSEG1_MAX - 1))
922 		<< ESD_USB2_TSEG1_SHIFT;
923 	canbtr |= ((bt->phase_seg2 - 1) & (ESD_USB2_TSEG2_MAX - 1))
924 		<< ESD_USB2_TSEG2_SHIFT;
925 	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
926 		canbtr |= ESD_USB2_3_SAMPLES;
927 
928 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
929 	if (!msg)
930 		return -ENOMEM;
931 
932 	msg->msg.hdr.len = 2;
933 	msg->msg.hdr.cmd = CMD_SETBAUD;
934 	msg->msg.setbaud.net = priv->index;
935 	msg->msg.setbaud.rsvd = 0;
936 	msg->msg.setbaud.baud = cpu_to_le32(canbtr);
937 
938 	netdev_info(netdev, "setting BTR=%#x\n", canbtr);
939 
940 	err = esd_usb_send_msg(priv->usb, msg);
941 
942 	kfree(msg);
943 	return err;
944 }
945 
946 static int esd_usb_get_berr_counter(const struct net_device *netdev,
947 				    struct can_berr_counter *bec)
948 {
949 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
950 
951 	bec->txerr = priv->bec.txerr;
952 	bec->rxerr = priv->bec.rxerr;
953 
954 	return 0;
955 }
956 
957 static int esd_usb_set_mode(struct net_device *netdev, enum can_mode mode)
958 {
959 	switch (mode) {
960 	case CAN_MODE_START:
961 		netif_wake_queue(netdev);
962 		break;
963 
964 	default:
965 		return -EOPNOTSUPP;
966 	}
967 
968 	return 0;
969 }
970 
971 static int esd_usb_probe_one_net(struct usb_interface *intf, int index)
972 {
973 	struct esd_usb *dev = usb_get_intfdata(intf);
974 	struct net_device *netdev;
975 	struct esd_usb_net_priv *priv;
976 	int err = 0;
977 	int i;
978 
979 	netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS);
980 	if (!netdev) {
981 		dev_err(&intf->dev, "couldn't alloc candev\n");
982 		err = -ENOMEM;
983 		goto done;
984 	}
985 
986 	priv = netdev_priv(netdev);
987 
988 	init_usb_anchor(&priv->tx_submitted);
989 	atomic_set(&priv->active_tx_jobs, 0);
990 
991 	for (i = 0; i < MAX_TX_URBS; i++)
992 		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
993 
994 	priv->usb = dev;
995 	priv->netdev = netdev;
996 	priv->index = index;
997 
998 	priv->can.state = CAN_STATE_STOPPED;
999 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY |
1000 		CAN_CTRLMODE_CC_LEN8_DLC;
1001 
1002 	if (le16_to_cpu(dev->udev->descriptor.idProduct) ==
1003 	    USB_CANUSBM_PRODUCT_ID)
1004 		priv->can.clock.freq = ESD_USBM_CAN_CLOCK;
1005 	else {
1006 		priv->can.clock.freq = ESD_USB2_CAN_CLOCK;
1007 		priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
1008 	}
1009 
1010 	priv->can.bittiming_const = &esd_usb2_bittiming_const;
1011 	priv->can.do_set_bittiming = esd_usb2_set_bittiming;
1012 	priv->can.do_set_mode = esd_usb_set_mode;
1013 	priv->can.do_get_berr_counter = esd_usb_get_berr_counter;
1014 
1015 	netdev->flags |= IFF_ECHO; /* we support local echo */
1016 
1017 	netdev->netdev_ops = &esd_usb_netdev_ops;
1018 
1019 	SET_NETDEV_DEV(netdev, &intf->dev);
1020 	netdev->dev_id = index;
1021 
1022 	err = register_candev(netdev);
1023 	if (err) {
1024 		dev_err(&intf->dev, "couldn't register CAN device: %d\n", err);
1025 		free_candev(netdev);
1026 		err = -ENOMEM;
1027 		goto done;
1028 	}
1029 
1030 	dev->nets[index] = priv;
1031 	netdev_info(netdev, "device %s registered\n", netdev->name);
1032 
1033 done:
1034 	return err;
1035 }
1036 
1037 /* probe function for new USB devices
1038  *
1039  * check version information and number of available
1040  * CAN interfaces
1041  */
1042 static int esd_usb_probe(struct usb_interface *intf,
1043 			 const struct usb_device_id *id)
1044 {
1045 	struct esd_usb *dev;
1046 	struct esd_usb_msg *msg;
1047 	int i, err;
1048 
1049 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1050 	if (!dev) {
1051 		err = -ENOMEM;
1052 		goto done;
1053 	}
1054 
1055 	dev->udev = interface_to_usbdev(intf);
1056 
1057 	init_usb_anchor(&dev->rx_submitted);
1058 
1059 	usb_set_intfdata(intf, dev);
1060 
1061 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
1062 	if (!msg) {
1063 		err = -ENOMEM;
1064 		goto free_msg;
1065 	}
1066 
1067 	/* query number of CAN interfaces (nets) */
1068 	msg->msg.hdr.cmd = CMD_VERSION;
1069 	msg->msg.hdr.len = 2;
1070 	msg->msg.version.rsvd = 0;
1071 	msg->msg.version.flags = 0;
1072 	msg->msg.version.drv_version = 0;
1073 
1074 	err = esd_usb_send_msg(dev, msg);
1075 	if (err < 0) {
1076 		dev_err(&intf->dev, "sending version message failed\n");
1077 		goto free_msg;
1078 	}
1079 
1080 	err = esd_usb_wait_msg(dev, msg);
1081 	if (err < 0) {
1082 		dev_err(&intf->dev, "no version message answer\n");
1083 		goto free_msg;
1084 	}
1085 
1086 	dev->net_count = (int)msg->msg.version_reply.nets;
1087 	dev->version = le32_to_cpu(msg->msg.version_reply.version);
1088 
1089 	if (device_create_file(&intf->dev, &dev_attr_firmware))
1090 		dev_err(&intf->dev,
1091 			"Couldn't create device file for firmware\n");
1092 
1093 	if (device_create_file(&intf->dev, &dev_attr_hardware))
1094 		dev_err(&intf->dev,
1095 			"Couldn't create device file for hardware\n");
1096 
1097 	if (device_create_file(&intf->dev, &dev_attr_nets))
1098 		dev_err(&intf->dev,
1099 			"Couldn't create device file for nets\n");
1100 
1101 	/* do per device probing */
1102 	for (i = 0; i < dev->net_count; i++)
1103 		esd_usb_probe_one_net(intf, i);
1104 
1105 free_msg:
1106 	kfree(msg);
1107 	if (err)
1108 		kfree(dev);
1109 done:
1110 	return err;
1111 }
1112 
1113 /* called by the usb core when the device is removed from the system */
1114 static void esd_usb_disconnect(struct usb_interface *intf)
1115 {
1116 	struct esd_usb *dev = usb_get_intfdata(intf);
1117 	struct net_device *netdev;
1118 	int i;
1119 
1120 	device_remove_file(&intf->dev, &dev_attr_firmware);
1121 	device_remove_file(&intf->dev, &dev_attr_hardware);
1122 	device_remove_file(&intf->dev, &dev_attr_nets);
1123 
1124 	usb_set_intfdata(intf, NULL);
1125 
1126 	if (dev) {
1127 		for (i = 0; i < dev->net_count; i++) {
1128 			if (dev->nets[i]) {
1129 				netdev = dev->nets[i]->netdev;
1130 				unregister_netdev(netdev);
1131 				free_candev(netdev);
1132 			}
1133 		}
1134 		unlink_all_urbs(dev);
1135 		kfree(dev);
1136 	}
1137 }
1138 
1139 /* usb specific object needed to register this driver with the usb subsystem */
1140 static struct usb_driver esd_usb_driver = {
1141 	.name = "esd_usb",
1142 	.probe = esd_usb_probe,
1143 	.disconnect = esd_usb_disconnect,
1144 	.id_table = esd_usb_table,
1145 };
1146 
1147 module_usb_driver(esd_usb_driver);
1148