xref: /openbmc/linux/drivers/net/can/usb/esd_usb.c (revision 3848636b)
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 
270 			switch (ecc & SJA1000_ECC_MASK) {
271 			case SJA1000_ECC_BIT:
272 				cf->data[2] |= CAN_ERR_PROT_BIT;
273 				break;
274 			case SJA1000_ECC_FORM:
275 				cf->data[2] |= CAN_ERR_PROT_FORM;
276 				break;
277 			case SJA1000_ECC_STUFF:
278 				cf->data[2] |= CAN_ERR_PROT_STUFF;
279 				break;
280 			default:
281 				cf->data[3] = ecc & SJA1000_ECC_SEG;
282 				break;
283 			}
284 
285 			/* Error occurred during transmission? */
286 			if (!(ecc & SJA1000_ECC_DIR))
287 				cf->data[2] |= CAN_ERR_PROT_TX;
288 
289 			if (priv->can.state == CAN_STATE_ERROR_WARNING ||
290 			    priv->can.state == CAN_STATE_ERROR_PASSIVE) {
291 				cf->data[1] = (txerr > rxerr) ?
292 					CAN_ERR_CRTL_TX_PASSIVE :
293 					CAN_ERR_CRTL_RX_PASSIVE;
294 			}
295 			cf->data[6] = txerr;
296 			cf->data[7] = rxerr;
297 		}
298 
299 		priv->bec.txerr = txerr;
300 		priv->bec.rxerr = rxerr;
301 
302 		netif_rx(skb);
303 	}
304 }
305 
306 static void esd_usb_rx_can_msg(struct esd_usb_net_priv *priv,
307 			       struct esd_usb_msg *msg)
308 {
309 	struct net_device_stats *stats = &priv->netdev->stats;
310 	struct can_frame *cf;
311 	struct sk_buff *skb;
312 	int i;
313 	u32 id;
314 
315 	if (!netif_device_present(priv->netdev))
316 		return;
317 
318 	id = le32_to_cpu(msg->msg.rx.id);
319 
320 	if (id & ESD_EVENT) {
321 		esd_usb_rx_event(priv, msg);
322 	} else {
323 		skb = alloc_can_skb(priv->netdev, &cf);
324 		if (skb == NULL) {
325 			stats->rx_dropped++;
326 			return;
327 		}
328 
329 		cf->can_id = id & ESD_IDMASK;
330 		can_frame_set_cc_len(cf, msg->msg.rx.dlc & ~ESD_RTR,
331 				     priv->can.ctrlmode);
332 
333 		if (id & ESD_EXTID)
334 			cf->can_id |= CAN_EFF_FLAG;
335 
336 		if (msg->msg.rx.dlc & ESD_RTR) {
337 			cf->can_id |= CAN_RTR_FLAG;
338 		} else {
339 			for (i = 0; i < cf->len; i++)
340 				cf->data[i] = msg->msg.rx.data[i];
341 
342 			stats->rx_bytes += cf->len;
343 		}
344 		stats->rx_packets++;
345 
346 		netif_rx(skb);
347 	}
348 }
349 
350 static void esd_usb_tx_done_msg(struct esd_usb_net_priv *priv,
351 				struct esd_usb_msg *msg)
352 {
353 	struct net_device_stats *stats = &priv->netdev->stats;
354 	struct net_device *netdev = priv->netdev;
355 	struct esd_tx_urb_context *context;
356 
357 	if (!netif_device_present(netdev))
358 		return;
359 
360 	context = &priv->tx_contexts[msg->msg.txdone.hnd & (MAX_TX_URBS - 1)];
361 
362 	if (!msg->msg.txdone.status) {
363 		stats->tx_packets++;
364 		stats->tx_bytes += can_get_echo_skb(netdev, context->echo_index,
365 						    NULL);
366 	} else {
367 		stats->tx_errors++;
368 		can_free_echo_skb(netdev, context->echo_index, NULL);
369 	}
370 
371 	/* Release context */
372 	context->echo_index = MAX_TX_URBS;
373 	atomic_dec(&priv->active_tx_jobs);
374 
375 	netif_wake_queue(netdev);
376 }
377 
378 static void esd_usb_read_bulk_callback(struct urb *urb)
379 {
380 	struct esd_usb *dev = urb->context;
381 	int retval;
382 	int pos = 0;
383 	int i;
384 
385 	switch (urb->status) {
386 	case 0: /* success */
387 		break;
388 
389 	case -ENOENT:
390 	case -EPIPE:
391 	case -EPROTO:
392 	case -ESHUTDOWN:
393 		return;
394 
395 	default:
396 		dev_info(dev->udev->dev.parent,
397 			 "Rx URB aborted (%d)\n", urb->status);
398 		goto resubmit_urb;
399 	}
400 
401 	while (pos < urb->actual_length) {
402 		struct esd_usb_msg *msg;
403 
404 		msg = (struct esd_usb_msg *)(urb->transfer_buffer + pos);
405 
406 		switch (msg->msg.hdr.cmd) {
407 		case CMD_CAN_RX:
408 			if (msg->msg.rx.net >= dev->net_count) {
409 				dev_err(dev->udev->dev.parent, "format error\n");
410 				break;
411 			}
412 
413 			esd_usb_rx_can_msg(dev->nets[msg->msg.rx.net], msg);
414 			break;
415 
416 		case CMD_CAN_TX:
417 			if (msg->msg.txdone.net >= dev->net_count) {
418 				dev_err(dev->udev->dev.parent, "format error\n");
419 				break;
420 			}
421 
422 			esd_usb_tx_done_msg(dev->nets[msg->msg.txdone.net],
423 					    msg);
424 			break;
425 		}
426 
427 		pos += msg->msg.hdr.len << 2;
428 
429 		if (pos > urb->actual_length) {
430 			dev_err(dev->udev->dev.parent, "format error\n");
431 			break;
432 		}
433 	}
434 
435 resubmit_urb:
436 	usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 1),
437 			  urb->transfer_buffer, RX_BUFFER_SIZE,
438 			  esd_usb_read_bulk_callback, dev);
439 
440 	retval = usb_submit_urb(urb, GFP_ATOMIC);
441 	if (retval == -ENODEV) {
442 		for (i = 0; i < dev->net_count; i++) {
443 			if (dev->nets[i])
444 				netif_device_detach(dev->nets[i]->netdev);
445 		}
446 	} else if (retval) {
447 		dev_err(dev->udev->dev.parent,
448 			"failed resubmitting read bulk urb: %d\n", retval);
449 	}
450 }
451 
452 /* callback for bulk IN urb */
453 static void esd_usb_write_bulk_callback(struct urb *urb)
454 {
455 	struct esd_tx_urb_context *context = urb->context;
456 	struct esd_usb_net_priv *priv;
457 	struct net_device *netdev;
458 	size_t size = sizeof(struct esd_usb_msg);
459 
460 	WARN_ON(!context);
461 
462 	priv = context->priv;
463 	netdev = priv->netdev;
464 
465 	/* free up our allocated buffer */
466 	usb_free_coherent(urb->dev, size,
467 			  urb->transfer_buffer, urb->transfer_dma);
468 
469 	if (!netif_device_present(netdev))
470 		return;
471 
472 	if (urb->status)
473 		netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
474 
475 	netif_trans_update(netdev);
476 }
477 
478 static ssize_t firmware_show(struct device *d,
479 			     struct device_attribute *attr, char *buf)
480 {
481 	struct usb_interface *intf = to_usb_interface(d);
482 	struct esd_usb *dev = usb_get_intfdata(intf);
483 
484 	return sprintf(buf, "%d.%d.%d\n",
485 		       (dev->version >> 12) & 0xf,
486 		       (dev->version >> 8) & 0xf,
487 		       dev->version & 0xff);
488 }
489 static DEVICE_ATTR_RO(firmware);
490 
491 static ssize_t hardware_show(struct device *d,
492 			     struct device_attribute *attr, char *buf)
493 {
494 	struct usb_interface *intf = to_usb_interface(d);
495 	struct esd_usb *dev = usb_get_intfdata(intf);
496 
497 	return sprintf(buf, "%d.%d.%d\n",
498 		       (dev->version >> 28) & 0xf,
499 		       (dev->version >> 24) & 0xf,
500 		       (dev->version >> 16) & 0xff);
501 }
502 static DEVICE_ATTR_RO(hardware);
503 
504 static ssize_t nets_show(struct device *d,
505 			 struct device_attribute *attr, char *buf)
506 {
507 	struct usb_interface *intf = to_usb_interface(d);
508 	struct esd_usb *dev = usb_get_intfdata(intf);
509 
510 	return sprintf(buf, "%d", dev->net_count);
511 }
512 static DEVICE_ATTR_RO(nets);
513 
514 static int esd_usb_send_msg(struct esd_usb *dev, struct esd_usb_msg *msg)
515 {
516 	int actual_length;
517 
518 	return usb_bulk_msg(dev->udev,
519 			    usb_sndbulkpipe(dev->udev, 2),
520 			    msg,
521 			    msg->msg.hdr.len << 2,
522 			    &actual_length,
523 			    1000);
524 }
525 
526 static int esd_usb_wait_msg(struct esd_usb *dev,
527 			    struct esd_usb_msg *msg)
528 {
529 	int actual_length;
530 
531 	return usb_bulk_msg(dev->udev,
532 			    usb_rcvbulkpipe(dev->udev, 1),
533 			    msg,
534 			    sizeof(*msg),
535 			    &actual_length,
536 			    1000);
537 }
538 
539 static int esd_usb_setup_rx_urbs(struct esd_usb *dev)
540 {
541 	int i, err = 0;
542 
543 	if (dev->rxinitdone)
544 		return 0;
545 
546 	for (i = 0; i < MAX_RX_URBS; i++) {
547 		struct urb *urb = NULL;
548 		u8 *buf = NULL;
549 		dma_addr_t buf_dma;
550 
551 		/* create a URB, and a buffer for it */
552 		urb = usb_alloc_urb(0, GFP_KERNEL);
553 		if (!urb) {
554 			err = -ENOMEM;
555 			break;
556 		}
557 
558 		buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
559 					 &buf_dma);
560 		if (!buf) {
561 			dev_warn(dev->udev->dev.parent,
562 				 "No memory left for USB buffer\n");
563 			err = -ENOMEM;
564 			goto freeurb;
565 		}
566 
567 		urb->transfer_dma = buf_dma;
568 
569 		usb_fill_bulk_urb(urb, dev->udev,
570 				  usb_rcvbulkpipe(dev->udev, 1),
571 				  buf, RX_BUFFER_SIZE,
572 				  esd_usb_read_bulk_callback, dev);
573 		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
574 		usb_anchor_urb(urb, &dev->rx_submitted);
575 
576 		err = usb_submit_urb(urb, GFP_KERNEL);
577 		if (err) {
578 			usb_unanchor_urb(urb);
579 			usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
580 					  urb->transfer_dma);
581 			goto freeurb;
582 		}
583 
584 		dev->rxbuf[i] = buf;
585 		dev->rxbuf_dma[i] = buf_dma;
586 
587 freeurb:
588 		/* Drop reference, USB core will take care of freeing it */
589 		usb_free_urb(urb);
590 		if (err)
591 			break;
592 	}
593 
594 	/* Did we submit any URBs */
595 	if (i == 0) {
596 		dev_err(dev->udev->dev.parent, "couldn't setup read URBs\n");
597 		return err;
598 	}
599 
600 	/* Warn if we've couldn't transmit all the URBs */
601 	if (i < MAX_RX_URBS) {
602 		dev_warn(dev->udev->dev.parent,
603 			 "rx performance may be slow\n");
604 	}
605 
606 	dev->rxinitdone = 1;
607 	return 0;
608 }
609 
610 /* Start interface */
611 static int esd_usb_start(struct esd_usb_net_priv *priv)
612 {
613 	struct esd_usb *dev = priv->usb;
614 	struct net_device *netdev = priv->netdev;
615 	struct esd_usb_msg *msg;
616 	int err, i;
617 
618 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
619 	if (!msg) {
620 		err = -ENOMEM;
621 		goto out;
622 	}
623 
624 	/* Enable all IDs
625 	 * The IDADD message takes up to 64 32 bit bitmasks (2048 bits).
626 	 * Each bit represents one 11 bit CAN identifier. A set bit
627 	 * enables reception of the corresponding CAN identifier. A cleared
628 	 * bit disabled this identifier. An additional bitmask value
629 	 * following the CAN 2.0A bits is used to enable reception of
630 	 * extended CAN frames. Only the LSB of this final mask is checked
631 	 * for the complete 29 bit ID range. The IDADD message also allows
632 	 * filter configuration for an ID subset. In this case you can add
633 	 * the number of the starting bitmask (0..64) to the filter.option
634 	 * field followed by only some bitmasks.
635 	 */
636 	msg->msg.hdr.cmd = CMD_IDADD;
637 	msg->msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
638 	msg->msg.filter.net = priv->index;
639 	msg->msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
640 	for (i = 0; i < ESD_MAX_ID_SEGMENT; i++)
641 		msg->msg.filter.mask[i] = cpu_to_le32(0xffffffff);
642 	/* enable 29bit extended IDs */
643 	msg->msg.filter.mask[ESD_MAX_ID_SEGMENT] = cpu_to_le32(0x00000001);
644 
645 	err = esd_usb_send_msg(dev, msg);
646 	if (err)
647 		goto out;
648 
649 	err = esd_usb_setup_rx_urbs(dev);
650 	if (err)
651 		goto out;
652 
653 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
654 
655 out:
656 	if (err == -ENODEV)
657 		netif_device_detach(netdev);
658 	if (err)
659 		netdev_err(netdev, "couldn't start device: %d\n", err);
660 
661 	kfree(msg);
662 	return err;
663 }
664 
665 static void unlink_all_urbs(struct esd_usb *dev)
666 {
667 	struct esd_usb_net_priv *priv;
668 	int i, j;
669 
670 	usb_kill_anchored_urbs(&dev->rx_submitted);
671 
672 	for (i = 0; i < MAX_RX_URBS; ++i)
673 		usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
674 				  dev->rxbuf[i], dev->rxbuf_dma[i]);
675 
676 	for (i = 0; i < dev->net_count; i++) {
677 		priv = dev->nets[i];
678 		if (priv) {
679 			usb_kill_anchored_urbs(&priv->tx_submitted);
680 			atomic_set(&priv->active_tx_jobs, 0);
681 
682 			for (j = 0; j < MAX_TX_URBS; j++)
683 				priv->tx_contexts[j].echo_index = MAX_TX_URBS;
684 		}
685 	}
686 }
687 
688 static int esd_usb_open(struct net_device *netdev)
689 {
690 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
691 	int err;
692 
693 	/* common open */
694 	err = open_candev(netdev);
695 	if (err)
696 		return err;
697 
698 	/* finally start device */
699 	err = esd_usb_start(priv);
700 	if (err) {
701 		netdev_warn(netdev, "couldn't start device: %d\n", err);
702 		close_candev(netdev);
703 		return err;
704 	}
705 
706 	netif_start_queue(netdev);
707 
708 	return 0;
709 }
710 
711 static netdev_tx_t esd_usb_start_xmit(struct sk_buff *skb,
712 				      struct net_device *netdev)
713 {
714 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
715 	struct esd_usb *dev = priv->usb;
716 	struct esd_tx_urb_context *context = NULL;
717 	struct net_device_stats *stats = &netdev->stats;
718 	struct can_frame *cf = (struct can_frame *)skb->data;
719 	struct esd_usb_msg *msg;
720 	struct urb *urb;
721 	u8 *buf;
722 	int i, err;
723 	int ret = NETDEV_TX_OK;
724 	size_t size = sizeof(struct esd_usb_msg);
725 
726 	if (can_dropped_invalid_skb(netdev, skb))
727 		return NETDEV_TX_OK;
728 
729 	/* create a URB, and a buffer for it, and copy the data to the URB */
730 	urb = usb_alloc_urb(0, GFP_ATOMIC);
731 	if (!urb) {
732 		stats->tx_dropped++;
733 		dev_kfree_skb(skb);
734 		goto nourbmem;
735 	}
736 
737 	buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC,
738 				 &urb->transfer_dma);
739 	if (!buf) {
740 		netdev_err(netdev, "No memory left for USB buffer\n");
741 		stats->tx_dropped++;
742 		dev_kfree_skb(skb);
743 		goto nobufmem;
744 	}
745 
746 	msg = (struct esd_usb_msg *)buf;
747 
748 	msg->msg.hdr.len = 3; /* minimal length */
749 	msg->msg.hdr.cmd = CMD_CAN_TX;
750 	msg->msg.tx.net = priv->index;
751 	msg->msg.tx.dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
752 	msg->msg.tx.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
753 
754 	if (cf->can_id & CAN_RTR_FLAG)
755 		msg->msg.tx.dlc |= ESD_RTR;
756 
757 	if (cf->can_id & CAN_EFF_FLAG)
758 		msg->msg.tx.id |= cpu_to_le32(ESD_EXTID);
759 
760 	for (i = 0; i < cf->len; i++)
761 		msg->msg.tx.data[i] = cf->data[i];
762 
763 	msg->msg.hdr.len += (cf->len + 3) >> 2;
764 
765 	for (i = 0; i < MAX_TX_URBS; i++) {
766 		if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
767 			context = &priv->tx_contexts[i];
768 			break;
769 		}
770 	}
771 
772 	/* This may never happen */
773 	if (!context) {
774 		netdev_warn(netdev, "couldn't find free context\n");
775 		ret = NETDEV_TX_BUSY;
776 		goto releasebuf;
777 	}
778 
779 	context->priv = priv;
780 	context->echo_index = i;
781 
782 	/* hnd must not be 0 - MSB is stripped in txdone handling */
783 	msg->msg.tx.hnd = 0x80000000 | i; /* returned in TX done message */
784 
785 	usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
786 			  msg->msg.hdr.len << 2,
787 			  esd_usb_write_bulk_callback, context);
788 
789 	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
790 
791 	usb_anchor_urb(urb, &priv->tx_submitted);
792 
793 	can_put_echo_skb(skb, netdev, context->echo_index, 0);
794 
795 	atomic_inc(&priv->active_tx_jobs);
796 
797 	/* Slow down tx path */
798 	if (atomic_read(&priv->active_tx_jobs) >= MAX_TX_URBS)
799 		netif_stop_queue(netdev);
800 
801 	err = usb_submit_urb(urb, GFP_ATOMIC);
802 	if (err) {
803 		can_free_echo_skb(netdev, context->echo_index, NULL);
804 
805 		atomic_dec(&priv->active_tx_jobs);
806 		usb_unanchor_urb(urb);
807 
808 		stats->tx_dropped++;
809 
810 		if (err == -ENODEV)
811 			netif_device_detach(netdev);
812 		else
813 			netdev_warn(netdev, "failed tx_urb %d\n", err);
814 
815 		goto releasebuf;
816 	}
817 
818 	netif_trans_update(netdev);
819 
820 	/* Release our reference to this URB, the USB core will eventually free
821 	 * it entirely.
822 	 */
823 	usb_free_urb(urb);
824 
825 	return NETDEV_TX_OK;
826 
827 releasebuf:
828 	usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
829 
830 nobufmem:
831 	usb_free_urb(urb);
832 
833 nourbmem:
834 	return ret;
835 }
836 
837 static int esd_usb_close(struct net_device *netdev)
838 {
839 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
840 	struct esd_usb_msg *msg;
841 	int i;
842 
843 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
844 	if (!msg)
845 		return -ENOMEM;
846 
847 	/* Disable all IDs (see esd_usb_start()) */
848 	msg->msg.hdr.cmd = CMD_IDADD;
849 	msg->msg.hdr.len = 2 + ESD_MAX_ID_SEGMENT;
850 	msg->msg.filter.net = priv->index;
851 	msg->msg.filter.option = ESD_ID_ENABLE; /* start with segment 0 */
852 	for (i = 0; i <= ESD_MAX_ID_SEGMENT; i++)
853 		msg->msg.filter.mask[i] = 0;
854 	if (esd_usb_send_msg(priv->usb, msg) < 0)
855 		netdev_err(netdev, "sending idadd message failed\n");
856 
857 	/* set CAN controller to reset mode */
858 	msg->msg.hdr.len = 2;
859 	msg->msg.hdr.cmd = CMD_SETBAUD;
860 	msg->msg.setbaud.net = priv->index;
861 	msg->msg.setbaud.rsvd = 0;
862 	msg->msg.setbaud.baud = cpu_to_le32(ESD_USB_NO_BAUDRATE);
863 	if (esd_usb_send_msg(priv->usb, msg) < 0)
864 		netdev_err(netdev, "sending setbaud message failed\n");
865 
866 	priv->can.state = CAN_STATE_STOPPED;
867 
868 	netif_stop_queue(netdev);
869 
870 	close_candev(netdev);
871 
872 	kfree(msg);
873 
874 	return 0;
875 }
876 
877 static const struct net_device_ops esd_usb_netdev_ops = {
878 	.ndo_open = esd_usb_open,
879 	.ndo_stop = esd_usb_close,
880 	.ndo_start_xmit = esd_usb_start_xmit,
881 	.ndo_change_mtu = can_change_mtu,
882 };
883 
884 static const struct can_bittiming_const esd_usb2_bittiming_const = {
885 	.name = "esd_usb2",
886 	.tseg1_min = ESD_USB2_TSEG1_MIN,
887 	.tseg1_max = ESD_USB2_TSEG1_MAX,
888 	.tseg2_min = ESD_USB2_TSEG2_MIN,
889 	.tseg2_max = ESD_USB2_TSEG2_MAX,
890 	.sjw_max = ESD_USB2_SJW_MAX,
891 	.brp_min = ESD_USB2_BRP_MIN,
892 	.brp_max = ESD_USB2_BRP_MAX,
893 	.brp_inc = ESD_USB2_BRP_INC,
894 };
895 
896 static int esd_usb2_set_bittiming(struct net_device *netdev)
897 {
898 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
899 	struct can_bittiming *bt = &priv->can.bittiming;
900 	struct esd_usb_msg *msg;
901 	int err;
902 	u32 canbtr;
903 	int sjw_shift;
904 
905 	canbtr = ESD_USB_UBR;
906 	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
907 		canbtr |= ESD_USB_LOM;
908 
909 	canbtr |= (bt->brp - 1) & (ESD_USB2_BRP_MAX - 1);
910 
911 	if (le16_to_cpu(priv->usb->udev->descriptor.idProduct) ==
912 	    USB_CANUSBM_PRODUCT_ID)
913 		sjw_shift = ESD_USBM_SJW_SHIFT;
914 	else
915 		sjw_shift = ESD_USB2_SJW_SHIFT;
916 
917 	canbtr |= ((bt->sjw - 1) & (ESD_USB2_SJW_MAX - 1))
918 		<< sjw_shift;
919 	canbtr |= ((bt->prop_seg + bt->phase_seg1 - 1)
920 		   & (ESD_USB2_TSEG1_MAX - 1))
921 		<< ESD_USB2_TSEG1_SHIFT;
922 	canbtr |= ((bt->phase_seg2 - 1) & (ESD_USB2_TSEG2_MAX - 1))
923 		<< ESD_USB2_TSEG2_SHIFT;
924 	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
925 		canbtr |= ESD_USB2_3_SAMPLES;
926 
927 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
928 	if (!msg)
929 		return -ENOMEM;
930 
931 	msg->msg.hdr.len = 2;
932 	msg->msg.hdr.cmd = CMD_SETBAUD;
933 	msg->msg.setbaud.net = priv->index;
934 	msg->msg.setbaud.rsvd = 0;
935 	msg->msg.setbaud.baud = cpu_to_le32(canbtr);
936 
937 	netdev_info(netdev, "setting BTR=%#x\n", canbtr);
938 
939 	err = esd_usb_send_msg(priv->usb, msg);
940 
941 	kfree(msg);
942 	return err;
943 }
944 
945 static int esd_usb_get_berr_counter(const struct net_device *netdev,
946 				    struct can_berr_counter *bec)
947 {
948 	struct esd_usb_net_priv *priv = netdev_priv(netdev);
949 
950 	bec->txerr = priv->bec.txerr;
951 	bec->rxerr = priv->bec.rxerr;
952 
953 	return 0;
954 }
955 
956 static int esd_usb_set_mode(struct net_device *netdev, enum can_mode mode)
957 {
958 	switch (mode) {
959 	case CAN_MODE_START:
960 		netif_wake_queue(netdev);
961 		break;
962 
963 	default:
964 		return -EOPNOTSUPP;
965 	}
966 
967 	return 0;
968 }
969 
970 static int esd_usb_probe_one_net(struct usb_interface *intf, int index)
971 {
972 	struct esd_usb *dev = usb_get_intfdata(intf);
973 	struct net_device *netdev;
974 	struct esd_usb_net_priv *priv;
975 	int err = 0;
976 	int i;
977 
978 	netdev = alloc_candev(sizeof(*priv), MAX_TX_URBS);
979 	if (!netdev) {
980 		dev_err(&intf->dev, "couldn't alloc candev\n");
981 		err = -ENOMEM;
982 		goto done;
983 	}
984 
985 	priv = netdev_priv(netdev);
986 
987 	init_usb_anchor(&priv->tx_submitted);
988 	atomic_set(&priv->active_tx_jobs, 0);
989 
990 	for (i = 0; i < MAX_TX_URBS; i++)
991 		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
992 
993 	priv->usb = dev;
994 	priv->netdev = netdev;
995 	priv->index = index;
996 
997 	priv->can.state = CAN_STATE_STOPPED;
998 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY |
999 		CAN_CTRLMODE_CC_LEN8_DLC;
1000 
1001 	if (le16_to_cpu(dev->udev->descriptor.idProduct) ==
1002 	    USB_CANUSBM_PRODUCT_ID)
1003 		priv->can.clock.freq = ESD_USBM_CAN_CLOCK;
1004 	else {
1005 		priv->can.clock.freq = ESD_USB2_CAN_CLOCK;
1006 		priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
1007 	}
1008 
1009 	priv->can.bittiming_const = &esd_usb2_bittiming_const;
1010 	priv->can.do_set_bittiming = esd_usb2_set_bittiming;
1011 	priv->can.do_set_mode = esd_usb_set_mode;
1012 	priv->can.do_get_berr_counter = esd_usb_get_berr_counter;
1013 
1014 	netdev->flags |= IFF_ECHO; /* we support local echo */
1015 
1016 	netdev->netdev_ops = &esd_usb_netdev_ops;
1017 
1018 	SET_NETDEV_DEV(netdev, &intf->dev);
1019 	netdev->dev_id = index;
1020 
1021 	err = register_candev(netdev);
1022 	if (err) {
1023 		dev_err(&intf->dev, "couldn't register CAN device: %d\n", err);
1024 		free_candev(netdev);
1025 		err = -ENOMEM;
1026 		goto done;
1027 	}
1028 
1029 	dev->nets[index] = priv;
1030 	netdev_info(netdev, "device %s registered\n", netdev->name);
1031 
1032 done:
1033 	return err;
1034 }
1035 
1036 /* probe function for new USB devices
1037  *
1038  * check version information and number of available
1039  * CAN interfaces
1040  */
1041 static int esd_usb_probe(struct usb_interface *intf,
1042 			 const struct usb_device_id *id)
1043 {
1044 	struct esd_usb *dev;
1045 	struct esd_usb_msg *msg;
1046 	int i, err;
1047 
1048 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1049 	if (!dev) {
1050 		err = -ENOMEM;
1051 		goto done;
1052 	}
1053 
1054 	dev->udev = interface_to_usbdev(intf);
1055 
1056 	init_usb_anchor(&dev->rx_submitted);
1057 
1058 	usb_set_intfdata(intf, dev);
1059 
1060 	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
1061 	if (!msg) {
1062 		err = -ENOMEM;
1063 		goto free_msg;
1064 	}
1065 
1066 	/* query number of CAN interfaces (nets) */
1067 	msg->msg.hdr.cmd = CMD_VERSION;
1068 	msg->msg.hdr.len = 2;
1069 	msg->msg.version.rsvd = 0;
1070 	msg->msg.version.flags = 0;
1071 	msg->msg.version.drv_version = 0;
1072 
1073 	err = esd_usb_send_msg(dev, msg);
1074 	if (err < 0) {
1075 		dev_err(&intf->dev, "sending version message failed\n");
1076 		goto free_msg;
1077 	}
1078 
1079 	err = esd_usb_wait_msg(dev, msg);
1080 	if (err < 0) {
1081 		dev_err(&intf->dev, "no version message answer\n");
1082 		goto free_msg;
1083 	}
1084 
1085 	dev->net_count = (int)msg->msg.version_reply.nets;
1086 	dev->version = le32_to_cpu(msg->msg.version_reply.version);
1087 
1088 	if (device_create_file(&intf->dev, &dev_attr_firmware))
1089 		dev_err(&intf->dev,
1090 			"Couldn't create device file for firmware\n");
1091 
1092 	if (device_create_file(&intf->dev, &dev_attr_hardware))
1093 		dev_err(&intf->dev,
1094 			"Couldn't create device file for hardware\n");
1095 
1096 	if (device_create_file(&intf->dev, &dev_attr_nets))
1097 		dev_err(&intf->dev,
1098 			"Couldn't create device file for nets\n");
1099 
1100 	/* do per device probing */
1101 	for (i = 0; i < dev->net_count; i++)
1102 		esd_usb_probe_one_net(intf, i);
1103 
1104 free_msg:
1105 	kfree(msg);
1106 	if (err)
1107 		kfree(dev);
1108 done:
1109 	return err;
1110 }
1111 
1112 /* called by the usb core when the device is removed from the system */
1113 static void esd_usb_disconnect(struct usb_interface *intf)
1114 {
1115 	struct esd_usb *dev = usb_get_intfdata(intf);
1116 	struct net_device *netdev;
1117 	int i;
1118 
1119 	device_remove_file(&intf->dev, &dev_attr_firmware);
1120 	device_remove_file(&intf->dev, &dev_attr_hardware);
1121 	device_remove_file(&intf->dev, &dev_attr_nets);
1122 
1123 	usb_set_intfdata(intf, NULL);
1124 
1125 	if (dev) {
1126 		for (i = 0; i < dev->net_count; i++) {
1127 			if (dev->nets[i]) {
1128 				netdev = dev->nets[i]->netdev;
1129 				unregister_netdev(netdev);
1130 				free_candev(netdev);
1131 			}
1132 		}
1133 		unlink_all_urbs(dev);
1134 		kfree(dev);
1135 	}
1136 }
1137 
1138 /* usb specific object needed to register this driver with the usb subsystem */
1139 static struct usb_driver esd_usb_driver = {
1140 	.name = "esd_usb",
1141 	.probe = esd_usb_probe,
1142 	.disconnect = esd_usb_disconnect,
1143 	.id_table = esd_usb_table,
1144 };
1145 
1146 module_usb_driver(esd_usb_driver);
1147