xref: /openbmc/linux/drivers/net/can/usb/usb_8dev.c (revision ae64438b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CAN driver for "8 devices" USB2CAN converter
4  *
5  * Copyright (C) 2012 Bernd Krumboeck (krumboeck@universalnet.at)
6  *
7  * This driver is inspired by the 3.2.0 version of drivers/net/can/usb/ems_usb.c
8  * and drivers/net/can/usb/esd_usb2.c
9  *
10  * Many thanks to Gerhard Bertelsmann (info@gerhard-bertelsmann.de)
11  * for testing and fixing this driver. Also many thanks to "8 devices",
12  * who were very cooperative and answered my questions.
13  */
14 
15 #include <linux/ethtool.h>
16 #include <linux/signal.h>
17 #include <linux/slab.h>
18 #include <linux/module.h>
19 #include <linux/netdevice.h>
20 #include <linux/usb.h>
21 
22 #include <linux/can.h>
23 #include <linux/can/dev.h>
24 #include <linux/can/error.h>
25 
26 /* driver constants */
27 #define MAX_RX_URBS			20
28 #define MAX_TX_URBS			20
29 #define RX_BUFFER_SIZE			64
30 
31 /* vendor and product id */
32 #define USB_8DEV_VENDOR_ID		0x0483
33 #define USB_8DEV_PRODUCT_ID		0x1234
34 
35 /* endpoints */
36 enum usb_8dev_endpoint {
37 	USB_8DEV_ENDP_DATA_RX = 1,
38 	USB_8DEV_ENDP_DATA_TX,
39 	USB_8DEV_ENDP_CMD_RX,
40 	USB_8DEV_ENDP_CMD_TX
41 };
42 
43 /* device CAN clock */
44 #define USB_8DEV_ABP_CLOCK		32000000
45 
46 /* setup flags */
47 #define USB_8DEV_SILENT			0x01
48 #define USB_8DEV_LOOPBACK		0x02
49 #define USB_8DEV_DISABLE_AUTO_RESTRANS	0x04
50 #define USB_8DEV_STATUS_FRAME		0x08
51 
52 /* commands */
53 enum usb_8dev_cmd {
54 	USB_8DEV_RESET = 1,
55 	USB_8DEV_OPEN,
56 	USB_8DEV_CLOSE,
57 	USB_8DEV_SET_SPEED,
58 	USB_8DEV_SET_MASK_FILTER,
59 	USB_8DEV_GET_STATUS,
60 	USB_8DEV_GET_STATISTICS,
61 	USB_8DEV_GET_SERIAL,
62 	USB_8DEV_GET_SOFTW_VER,
63 	USB_8DEV_GET_HARDW_VER,
64 	USB_8DEV_RESET_TIMESTAMP,
65 	USB_8DEV_GET_SOFTW_HARDW_VER
66 };
67 
68 /* command options */
69 #define USB_8DEV_BAUD_MANUAL		0x09
70 #define USB_8DEV_CMD_START		0x11
71 #define USB_8DEV_CMD_END		0x22
72 
73 #define USB_8DEV_CMD_SUCCESS		0
74 #define USB_8DEV_CMD_ERROR		255
75 
76 #define USB_8DEV_CMD_TIMEOUT		1000
77 
78 /* frames */
79 #define USB_8DEV_DATA_START		0x55
80 #define USB_8DEV_DATA_END		0xAA
81 
82 #define USB_8DEV_TYPE_CAN_FRAME		0
83 #define USB_8DEV_TYPE_ERROR_FRAME	3
84 
85 #define USB_8DEV_EXTID			0x01
86 #define USB_8DEV_RTR			0x02
87 #define USB_8DEV_ERR_FLAG		0x04
88 
89 /* status */
90 #define USB_8DEV_STATUSMSG_OK		0x00  /* Normal condition. */
91 #define USB_8DEV_STATUSMSG_OVERRUN	0x01  /* Overrun occurred when sending */
92 #define USB_8DEV_STATUSMSG_BUSLIGHT	0x02  /* Error counter has reached 96 */
93 #define USB_8DEV_STATUSMSG_BUSHEAVY	0x03  /* Error count. has reached 128 */
94 #define USB_8DEV_STATUSMSG_BUSOFF	0x04  /* Device is in BUSOFF */
95 #define USB_8DEV_STATUSMSG_STUFF	0x20  /* Stuff Error */
96 #define USB_8DEV_STATUSMSG_FORM		0x21  /* Form Error */
97 #define USB_8DEV_STATUSMSG_ACK		0x23  /* Ack Error */
98 #define USB_8DEV_STATUSMSG_BIT0		0x24  /* Bit1 Error */
99 #define USB_8DEV_STATUSMSG_BIT1		0x25  /* Bit0 Error */
100 #define USB_8DEV_STATUSMSG_CRC		0x27  /* CRC Error */
101 
102 #define USB_8DEV_RP_MASK		0x7F  /* Mask for Receive Error Bit */
103 
104 
105 /* table of devices that work with this driver */
106 static const struct usb_device_id usb_8dev_table[] = {
107 	{ USB_DEVICE(USB_8DEV_VENDOR_ID, USB_8DEV_PRODUCT_ID) },
108 	{ }					/* Terminating entry */
109 };
110 
111 MODULE_DEVICE_TABLE(usb, usb_8dev_table);
112 
113 struct usb_8dev_tx_urb_context {
114 	struct usb_8dev_priv *priv;
115 
116 	u32 echo_index;
117 };
118 
119 /* Structure to hold all of our device specific stuff */
120 struct usb_8dev_priv {
121 	struct can_priv can; /* must be the first member */
122 
123 	struct usb_device *udev;
124 	struct net_device *netdev;
125 
126 	atomic_t active_tx_urbs;
127 	struct usb_anchor tx_submitted;
128 	struct usb_8dev_tx_urb_context tx_contexts[MAX_TX_URBS];
129 
130 	struct usb_anchor rx_submitted;
131 
132 	struct can_berr_counter bec;
133 
134 	u8 *cmd_msg_buffer;
135 
136 	struct mutex usb_8dev_cmd_lock;
137 	void *rxbuf[MAX_RX_URBS];
138 	dma_addr_t rxbuf_dma[MAX_RX_URBS];
139 };
140 
141 /* tx frame */
142 struct __packed usb_8dev_tx_msg {
143 	u8 begin;
144 	u8 flags;	/* RTR and EXT_ID flag */
145 	__be32 id;	/* upper 3 bits not used */
146 	u8 dlc;		/* data length code 0-8 bytes */
147 	u8 data[8];	/* 64-bit data */
148 	u8 end;
149 };
150 
151 /* rx frame */
152 struct __packed usb_8dev_rx_msg {
153 	u8 begin;
154 	u8 type;		/* frame type */
155 	u8 flags;		/* RTR and EXT_ID flag */
156 	__be32 id;		/* upper 3 bits not used */
157 	u8 dlc;			/* data length code 0-8 bytes */
158 	u8 data[8];		/* 64-bit data */
159 	__be32 timestamp;	/* 32-bit timestamp */
160 	u8 end;
161 };
162 
163 /* command frame */
164 struct __packed usb_8dev_cmd_msg {
165 	u8 begin;
166 	u8 channel;	/* unknown - always 0 */
167 	u8 command;	/* command to execute */
168 	u8 opt1;	/* optional parameter / return value */
169 	u8 opt2;	/* optional parameter 2 */
170 	u8 data[10];	/* optional parameter and data */
171 	u8 end;
172 };
173 
usb_8dev_send_cmd_msg(struct usb_8dev_priv * priv,u8 * msg,int size)174 static int usb_8dev_send_cmd_msg(struct usb_8dev_priv *priv, u8 *msg, int size)
175 {
176 	int actual_length;
177 
178 	return usb_bulk_msg(priv->udev,
179 			    usb_sndbulkpipe(priv->udev, USB_8DEV_ENDP_CMD_TX),
180 			    msg, size, &actual_length, USB_8DEV_CMD_TIMEOUT);
181 }
182 
usb_8dev_wait_cmd_msg(struct usb_8dev_priv * priv,u8 * msg,int size,int * actual_length)183 static int usb_8dev_wait_cmd_msg(struct usb_8dev_priv *priv, u8 *msg, int size,
184 				int *actual_length)
185 {
186 	return usb_bulk_msg(priv->udev,
187 			    usb_rcvbulkpipe(priv->udev, USB_8DEV_ENDP_CMD_RX),
188 			    msg, size, actual_length, USB_8DEV_CMD_TIMEOUT);
189 }
190 
191 /* Send command to device and receive result.
192  * Command was successful when opt1 = 0.
193  */
usb_8dev_send_cmd(struct usb_8dev_priv * priv,struct usb_8dev_cmd_msg * out,struct usb_8dev_cmd_msg * in)194 static int usb_8dev_send_cmd(struct usb_8dev_priv *priv,
195 			     struct usb_8dev_cmd_msg *out,
196 			     struct usb_8dev_cmd_msg *in)
197 {
198 	int err;
199 	int num_bytes_read;
200 	struct net_device *netdev;
201 
202 	netdev = priv->netdev;
203 
204 	out->begin = USB_8DEV_CMD_START;
205 	out->end = USB_8DEV_CMD_END;
206 
207 	mutex_lock(&priv->usb_8dev_cmd_lock);
208 
209 	memcpy(priv->cmd_msg_buffer, out,
210 		sizeof(struct usb_8dev_cmd_msg));
211 
212 	err = usb_8dev_send_cmd_msg(priv, priv->cmd_msg_buffer,
213 				    sizeof(struct usb_8dev_cmd_msg));
214 	if (err < 0) {
215 		netdev_err(netdev, "sending command message failed\n");
216 		goto failed;
217 	}
218 
219 	err = usb_8dev_wait_cmd_msg(priv, priv->cmd_msg_buffer,
220 				    sizeof(struct usb_8dev_cmd_msg),
221 				    &num_bytes_read);
222 	if (err < 0) {
223 		netdev_err(netdev, "no command message answer\n");
224 		goto failed;
225 	}
226 
227 	memcpy(in, priv->cmd_msg_buffer, sizeof(struct usb_8dev_cmd_msg));
228 
229 	if (in->begin != USB_8DEV_CMD_START || in->end != USB_8DEV_CMD_END ||
230 			num_bytes_read != 16 || in->opt1 != 0)
231 		err = -EPROTO;
232 
233 failed:
234 	mutex_unlock(&priv->usb_8dev_cmd_lock);
235 	return err;
236 }
237 
238 /* Send open command to device */
usb_8dev_cmd_open(struct usb_8dev_priv * priv)239 static int usb_8dev_cmd_open(struct usb_8dev_priv *priv)
240 {
241 	struct can_bittiming *bt = &priv->can.bittiming;
242 	struct usb_8dev_cmd_msg outmsg;
243 	struct usb_8dev_cmd_msg inmsg;
244 	u32 ctrlmode = priv->can.ctrlmode;
245 	u32 flags = USB_8DEV_STATUS_FRAME;
246 	__be32 beflags;
247 	__be16 bebrp;
248 
249 	memset(&outmsg, 0, sizeof(outmsg));
250 	outmsg.command = USB_8DEV_OPEN;
251 	outmsg.opt1 = USB_8DEV_BAUD_MANUAL;
252 	outmsg.data[0] = bt->prop_seg + bt->phase_seg1;
253 	outmsg.data[1] = bt->phase_seg2;
254 	outmsg.data[2] = bt->sjw;
255 
256 	/* BRP */
257 	bebrp = cpu_to_be16((u16)bt->brp);
258 	memcpy(&outmsg.data[3], &bebrp, sizeof(bebrp));
259 
260 	/* flags */
261 	if (ctrlmode & CAN_CTRLMODE_LOOPBACK)
262 		flags |= USB_8DEV_LOOPBACK;
263 	if (ctrlmode & CAN_CTRLMODE_LISTENONLY)
264 		flags |= USB_8DEV_SILENT;
265 	if (ctrlmode & CAN_CTRLMODE_ONE_SHOT)
266 		flags |= USB_8DEV_DISABLE_AUTO_RESTRANS;
267 
268 	beflags = cpu_to_be32(flags);
269 	memcpy(&outmsg.data[5], &beflags, sizeof(beflags));
270 
271 	return usb_8dev_send_cmd(priv, &outmsg, &inmsg);
272 }
273 
274 /* Send close command to device */
usb_8dev_cmd_close(struct usb_8dev_priv * priv)275 static int usb_8dev_cmd_close(struct usb_8dev_priv *priv)
276 {
277 	struct usb_8dev_cmd_msg inmsg;
278 	struct usb_8dev_cmd_msg outmsg = {
279 		.channel = 0,
280 		.command = USB_8DEV_CLOSE,
281 		.opt1 = 0,
282 		.opt2 = 0
283 	};
284 
285 	return usb_8dev_send_cmd(priv, &outmsg, &inmsg);
286 }
287 
288 /* Get firmware and hardware version */
usb_8dev_cmd_version(struct usb_8dev_priv * priv,u32 * res)289 static int usb_8dev_cmd_version(struct usb_8dev_priv *priv, u32 *res)
290 {
291 	struct usb_8dev_cmd_msg	inmsg;
292 	struct usb_8dev_cmd_msg	outmsg = {
293 		.channel = 0,
294 		.command = USB_8DEV_GET_SOFTW_HARDW_VER,
295 		.opt1 = 0,
296 		.opt2 = 0
297 	};
298 
299 	int err = usb_8dev_send_cmd(priv, &outmsg, &inmsg);
300 	if (err)
301 		return err;
302 
303 	*res = be32_to_cpup((__be32 *)inmsg.data);
304 
305 	return err;
306 }
307 
308 /* Set network device mode
309  *
310  * Maybe we should leave this function empty, because the device
311  * set mode variable with open command.
312  */
usb_8dev_set_mode(struct net_device * netdev,enum can_mode mode)313 static int usb_8dev_set_mode(struct net_device *netdev, enum can_mode mode)
314 {
315 	struct usb_8dev_priv *priv = netdev_priv(netdev);
316 	int err = 0;
317 
318 	switch (mode) {
319 	case CAN_MODE_START:
320 		err = usb_8dev_cmd_open(priv);
321 		if (err)
322 			netdev_warn(netdev, "couldn't start device");
323 		break;
324 
325 	default:
326 		return -EOPNOTSUPP;
327 	}
328 
329 	return err;
330 }
331 
332 /* Read error/status frames */
usb_8dev_rx_err_msg(struct usb_8dev_priv * priv,struct usb_8dev_rx_msg * msg)333 static void usb_8dev_rx_err_msg(struct usb_8dev_priv *priv,
334 				struct usb_8dev_rx_msg *msg)
335 {
336 	struct can_frame *cf;
337 	struct sk_buff *skb;
338 	struct net_device_stats *stats = &priv->netdev->stats;
339 
340 	/* Error message:
341 	 * byte 0: Status
342 	 * byte 1: bit   7: Receive Passive
343 	 * byte 1: bit 0-6: Receive Error Counter
344 	 * byte 2: Transmit Error Counter
345 	 * byte 3: Always 0 (maybe reserved for future use)
346 	 */
347 
348 	u8 state = msg->data[0];
349 	u8 rxerr = msg->data[1] & USB_8DEV_RP_MASK;
350 	u8 txerr = msg->data[2];
351 	int rx_errors = 0;
352 	int tx_errors = 0;
353 
354 	skb = alloc_can_err_skb(priv->netdev, &cf);
355 	if (!skb)
356 		return;
357 
358 	switch (state) {
359 	case USB_8DEV_STATUSMSG_OK:
360 		priv->can.state = CAN_STATE_ERROR_ACTIVE;
361 		cf->can_id |= CAN_ERR_PROT;
362 		cf->data[2] = CAN_ERR_PROT_ACTIVE;
363 		break;
364 	case USB_8DEV_STATUSMSG_BUSOFF:
365 		priv->can.state = CAN_STATE_BUS_OFF;
366 		cf->can_id |= CAN_ERR_BUSOFF;
367 		priv->can.can_stats.bus_off++;
368 		can_bus_off(priv->netdev);
369 		break;
370 	case USB_8DEV_STATUSMSG_OVERRUN:
371 	case USB_8DEV_STATUSMSG_BUSLIGHT:
372 	case USB_8DEV_STATUSMSG_BUSHEAVY:
373 		cf->can_id |= CAN_ERR_CRTL;
374 		break;
375 	default:
376 		priv->can.state = CAN_STATE_ERROR_WARNING;
377 		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
378 		priv->can.can_stats.bus_error++;
379 		break;
380 	}
381 
382 	switch (state) {
383 	case USB_8DEV_STATUSMSG_OK:
384 	case USB_8DEV_STATUSMSG_BUSOFF:
385 		break;
386 	case USB_8DEV_STATUSMSG_ACK:
387 		cf->can_id |= CAN_ERR_ACK;
388 		tx_errors = 1;
389 		break;
390 	case USB_8DEV_STATUSMSG_CRC:
391 		cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
392 		rx_errors = 1;
393 		break;
394 	case USB_8DEV_STATUSMSG_BIT0:
395 		cf->data[2] |= CAN_ERR_PROT_BIT0;
396 		tx_errors = 1;
397 		break;
398 	case USB_8DEV_STATUSMSG_BIT1:
399 		cf->data[2] |= CAN_ERR_PROT_BIT1;
400 		tx_errors = 1;
401 		break;
402 	case USB_8DEV_STATUSMSG_FORM:
403 		cf->data[2] |= CAN_ERR_PROT_FORM;
404 		rx_errors = 1;
405 		break;
406 	case USB_8DEV_STATUSMSG_STUFF:
407 		cf->data[2] |= CAN_ERR_PROT_STUFF;
408 		rx_errors = 1;
409 		break;
410 	case USB_8DEV_STATUSMSG_OVERRUN:
411 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
412 		stats->rx_over_errors++;
413 		rx_errors = 1;
414 		break;
415 	case USB_8DEV_STATUSMSG_BUSLIGHT:
416 		priv->can.state = CAN_STATE_ERROR_WARNING;
417 		cf->data[1] = (txerr > rxerr) ?
418 			CAN_ERR_CRTL_TX_WARNING :
419 			CAN_ERR_CRTL_RX_WARNING;
420 		priv->can.can_stats.error_warning++;
421 		break;
422 	case USB_8DEV_STATUSMSG_BUSHEAVY:
423 		priv->can.state = CAN_STATE_ERROR_PASSIVE;
424 		cf->data[1] = (txerr > rxerr) ?
425 			CAN_ERR_CRTL_TX_PASSIVE :
426 			CAN_ERR_CRTL_RX_PASSIVE;
427 		priv->can.can_stats.error_passive++;
428 		break;
429 	default:
430 		netdev_warn(priv->netdev,
431 			    "Unknown status/error message (%d)\n", state);
432 		break;
433 	}
434 
435 	if (tx_errors) {
436 		cf->data[2] |= CAN_ERR_PROT_TX;
437 		stats->tx_errors++;
438 	}
439 
440 	if (rx_errors)
441 		stats->rx_errors++;
442 	if (priv->can.state != CAN_STATE_BUS_OFF) {
443 		cf->can_id |= CAN_ERR_CNT;
444 		cf->data[6] = txerr;
445 		cf->data[7] = rxerr;
446 	}
447 
448 	priv->bec.txerr = txerr;
449 	priv->bec.rxerr = rxerr;
450 
451 	netif_rx(skb);
452 }
453 
454 /* Read data and status frames */
usb_8dev_rx_can_msg(struct usb_8dev_priv * priv,struct usb_8dev_rx_msg * msg)455 static void usb_8dev_rx_can_msg(struct usb_8dev_priv *priv,
456 				struct usb_8dev_rx_msg *msg)
457 {
458 	struct can_frame *cf;
459 	struct sk_buff *skb;
460 	struct net_device_stats *stats = &priv->netdev->stats;
461 
462 	if (msg->type == USB_8DEV_TYPE_ERROR_FRAME &&
463 		   msg->flags == USB_8DEV_ERR_FLAG) {
464 		usb_8dev_rx_err_msg(priv, msg);
465 	} else if (msg->type == USB_8DEV_TYPE_CAN_FRAME) {
466 		skb = alloc_can_skb(priv->netdev, &cf);
467 		if (!skb)
468 			return;
469 
470 		cf->can_id = be32_to_cpu(msg->id);
471 		can_frame_set_cc_len(cf, msg->dlc & 0xF, priv->can.ctrlmode);
472 
473 		if (msg->flags & USB_8DEV_EXTID)
474 			cf->can_id |= CAN_EFF_FLAG;
475 
476 		if (msg->flags & USB_8DEV_RTR) {
477 			cf->can_id |= CAN_RTR_FLAG;
478 		} else {
479 			memcpy(cf->data, msg->data, cf->len);
480 			stats->rx_bytes += cf->len;
481 		}
482 		stats->rx_packets++;
483 
484 		netif_rx(skb);
485 	} else {
486 		netdev_warn(priv->netdev, "frame type %d unknown",
487 			 msg->type);
488 	}
489 
490 }
491 
492 /* Callback for reading data from device
493  *
494  * Check urb status, call read function and resubmit urb read operation.
495  */
usb_8dev_read_bulk_callback(struct urb * urb)496 static void usb_8dev_read_bulk_callback(struct urb *urb)
497 {
498 	struct usb_8dev_priv *priv = urb->context;
499 	struct net_device *netdev;
500 	int retval;
501 	int pos = 0;
502 
503 	netdev = priv->netdev;
504 
505 	if (!netif_device_present(netdev))
506 		return;
507 
508 	switch (urb->status) {
509 	case 0: /* success */
510 		break;
511 
512 	case -ENOENT:
513 	case -EPIPE:
514 	case -EPROTO:
515 	case -ESHUTDOWN:
516 		return;
517 
518 	default:
519 		netdev_info(netdev, "Rx URB aborted (%d)\n",
520 			 urb->status);
521 		goto resubmit_urb;
522 	}
523 
524 	while (pos < urb->actual_length) {
525 		struct usb_8dev_rx_msg *msg;
526 
527 		if (pos + sizeof(struct usb_8dev_rx_msg) > urb->actual_length) {
528 			netdev_err(priv->netdev, "format error\n");
529 			break;
530 		}
531 
532 		msg = (struct usb_8dev_rx_msg *)(urb->transfer_buffer + pos);
533 		usb_8dev_rx_can_msg(priv, msg);
534 
535 		pos += sizeof(struct usb_8dev_rx_msg);
536 	}
537 
538 resubmit_urb:
539 	usb_fill_bulk_urb(urb, priv->udev,
540 			  usb_rcvbulkpipe(priv->udev, USB_8DEV_ENDP_DATA_RX),
541 			  urb->transfer_buffer, RX_BUFFER_SIZE,
542 			  usb_8dev_read_bulk_callback, priv);
543 
544 	retval = usb_submit_urb(urb, GFP_ATOMIC);
545 
546 	if (retval == -ENODEV)
547 		netif_device_detach(netdev);
548 	else if (retval)
549 		netdev_err(netdev,
550 			"failed resubmitting read bulk urb: %d\n", retval);
551 }
552 
553 /* Callback handler for write operations
554  *
555  * Free allocated buffers, check transmit status and
556  * calculate statistic.
557  */
usb_8dev_write_bulk_callback(struct urb * urb)558 static void usb_8dev_write_bulk_callback(struct urb *urb)
559 {
560 	struct usb_8dev_tx_urb_context *context = urb->context;
561 	struct usb_8dev_priv *priv;
562 	struct net_device *netdev;
563 
564 	BUG_ON(!context);
565 
566 	priv = context->priv;
567 	netdev = priv->netdev;
568 
569 	/* free up our allocated buffer */
570 	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
571 			  urb->transfer_buffer, urb->transfer_dma);
572 
573 	atomic_dec(&priv->active_tx_urbs);
574 
575 	if (!netif_device_present(netdev))
576 		return;
577 
578 	if (urb->status)
579 		netdev_info(netdev, "Tx URB aborted (%d)\n",
580 			 urb->status);
581 
582 	netdev->stats.tx_packets++;
583 	netdev->stats.tx_bytes += can_get_echo_skb(netdev, context->echo_index, NULL);
584 
585 	/* Release context */
586 	context->echo_index = MAX_TX_URBS;
587 
588 	netif_wake_queue(netdev);
589 }
590 
591 /* Send data to device */
usb_8dev_start_xmit(struct sk_buff * skb,struct net_device * netdev)592 static netdev_tx_t usb_8dev_start_xmit(struct sk_buff *skb,
593 				      struct net_device *netdev)
594 {
595 	struct usb_8dev_priv *priv = netdev_priv(netdev);
596 	struct net_device_stats *stats = &netdev->stats;
597 	struct can_frame *cf = (struct can_frame *) skb->data;
598 	struct usb_8dev_tx_msg *msg;
599 	struct urb *urb;
600 	struct usb_8dev_tx_urb_context *context = NULL;
601 	u8 *buf;
602 	int i, err;
603 	size_t size = sizeof(struct usb_8dev_tx_msg);
604 
605 	if (can_dev_dropped_skb(netdev, skb))
606 		return NETDEV_TX_OK;
607 
608 	/* create a URB, and a buffer for it, and copy the data to the URB */
609 	urb = usb_alloc_urb(0, GFP_ATOMIC);
610 	if (!urb)
611 		goto nomem;
612 
613 	buf = usb_alloc_coherent(priv->udev, size, GFP_ATOMIC,
614 				 &urb->transfer_dma);
615 	if (!buf) {
616 		netdev_err(netdev, "No memory left for USB buffer\n");
617 		goto nomembuf;
618 	}
619 
620 	memset(buf, 0, size);
621 
622 	msg = (struct usb_8dev_tx_msg *)buf;
623 	msg->begin = USB_8DEV_DATA_START;
624 	msg->flags = 0x00;
625 
626 	if (cf->can_id & CAN_RTR_FLAG)
627 		msg->flags |= USB_8DEV_RTR;
628 
629 	if (cf->can_id & CAN_EFF_FLAG)
630 		msg->flags |= USB_8DEV_EXTID;
631 
632 	msg->id = cpu_to_be32(cf->can_id & CAN_ERR_MASK);
633 	msg->dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
634 	memcpy(msg->data, cf->data, cf->len);
635 	msg->end = USB_8DEV_DATA_END;
636 
637 	for (i = 0; i < MAX_TX_URBS; i++) {
638 		if (priv->tx_contexts[i].echo_index == MAX_TX_URBS) {
639 			context = &priv->tx_contexts[i];
640 			break;
641 		}
642 	}
643 
644 	/* May never happen! When this happens we'd more URBs in flight as
645 	 * allowed (MAX_TX_URBS).
646 	 */
647 	if (!context)
648 		goto nofreecontext;
649 
650 	context->priv = priv;
651 	context->echo_index = i;
652 
653 	usb_fill_bulk_urb(urb, priv->udev,
654 			  usb_sndbulkpipe(priv->udev, USB_8DEV_ENDP_DATA_TX),
655 			  buf, size, usb_8dev_write_bulk_callback, context);
656 	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
657 	usb_anchor_urb(urb, &priv->tx_submitted);
658 
659 	can_put_echo_skb(skb, netdev, context->echo_index, 0);
660 
661 	atomic_inc(&priv->active_tx_urbs);
662 
663 	err = usb_submit_urb(urb, GFP_ATOMIC);
664 	if (unlikely(err)) {
665 		can_free_echo_skb(netdev, context->echo_index, NULL);
666 
667 		usb_unanchor_urb(urb);
668 		usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
669 
670 		atomic_dec(&priv->active_tx_urbs);
671 
672 		if (err == -ENODEV)
673 			netif_device_detach(netdev);
674 		else
675 			netdev_warn(netdev, "failed tx_urb %d\n", err);
676 		stats->tx_dropped++;
677 	} else if (atomic_read(&priv->active_tx_urbs) >= MAX_TX_URBS)
678 		/* Slow down tx path */
679 		netif_stop_queue(netdev);
680 
681 	/* Release our reference to this URB, the USB core will eventually free
682 	 * it entirely.
683 	 */
684 	usb_free_urb(urb);
685 
686 	return NETDEV_TX_OK;
687 
688 nofreecontext:
689 	usb_free_coherent(priv->udev, size, buf, urb->transfer_dma);
690 	usb_free_urb(urb);
691 
692 	netdev_warn(netdev, "couldn't find free context");
693 
694 	return NETDEV_TX_BUSY;
695 
696 nomembuf:
697 	usb_free_urb(urb);
698 
699 nomem:
700 	dev_kfree_skb(skb);
701 	stats->tx_dropped++;
702 
703 	return NETDEV_TX_OK;
704 }
705 
usb_8dev_get_berr_counter(const struct net_device * netdev,struct can_berr_counter * bec)706 static int usb_8dev_get_berr_counter(const struct net_device *netdev,
707 				     struct can_berr_counter *bec)
708 {
709 	struct usb_8dev_priv *priv = netdev_priv(netdev);
710 
711 	bec->txerr = priv->bec.txerr;
712 	bec->rxerr = priv->bec.rxerr;
713 
714 	return 0;
715 }
716 
717 /* Start USB device */
usb_8dev_start(struct usb_8dev_priv * priv)718 static int usb_8dev_start(struct usb_8dev_priv *priv)
719 {
720 	struct net_device *netdev = priv->netdev;
721 	int err, i;
722 
723 	for (i = 0; i < MAX_RX_URBS; i++) {
724 		struct urb *urb = NULL;
725 		u8 *buf;
726 		dma_addr_t buf_dma;
727 
728 		/* create a URB, and a buffer for it */
729 		urb = usb_alloc_urb(0, GFP_KERNEL);
730 		if (!urb) {
731 			err = -ENOMEM;
732 			break;
733 		}
734 
735 		buf = usb_alloc_coherent(priv->udev, RX_BUFFER_SIZE, GFP_KERNEL,
736 					 &buf_dma);
737 		if (!buf) {
738 			netdev_err(netdev, "No memory left for USB buffer\n");
739 			usb_free_urb(urb);
740 			err = -ENOMEM;
741 			break;
742 		}
743 
744 		urb->transfer_dma = buf_dma;
745 
746 		usb_fill_bulk_urb(urb, priv->udev,
747 				  usb_rcvbulkpipe(priv->udev,
748 						  USB_8DEV_ENDP_DATA_RX),
749 				  buf, RX_BUFFER_SIZE,
750 				  usb_8dev_read_bulk_callback, priv);
751 		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
752 		usb_anchor_urb(urb, &priv->rx_submitted);
753 
754 		err = usb_submit_urb(urb, GFP_KERNEL);
755 		if (err) {
756 			usb_unanchor_urb(urb);
757 			usb_free_coherent(priv->udev, RX_BUFFER_SIZE, buf,
758 					  urb->transfer_dma);
759 			usb_free_urb(urb);
760 			break;
761 		}
762 
763 		priv->rxbuf[i] = buf;
764 		priv->rxbuf_dma[i] = buf_dma;
765 
766 		/* Drop reference, USB core will take care of freeing it */
767 		usb_free_urb(urb);
768 	}
769 
770 	/* Did we submit any URBs */
771 	if (i == 0) {
772 		netdev_warn(netdev, "couldn't setup read URBs\n");
773 		return err;
774 	}
775 
776 	/* Warn if we've couldn't transmit all the URBs */
777 	if (i < MAX_RX_URBS)
778 		netdev_warn(netdev, "rx performance may be slow\n");
779 
780 	err = usb_8dev_cmd_open(priv);
781 	if (err)
782 		goto failed;
783 
784 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
785 
786 	return 0;
787 
788 failed:
789 	if (err == -ENODEV)
790 		netif_device_detach(priv->netdev);
791 
792 	netdev_warn(netdev, "couldn't submit control: %d\n", err);
793 
794 	return err;
795 }
796 
797 /* Open USB device */
usb_8dev_open(struct net_device * netdev)798 static int usb_8dev_open(struct net_device *netdev)
799 {
800 	struct usb_8dev_priv *priv = netdev_priv(netdev);
801 	int err;
802 
803 	/* common open */
804 	err = open_candev(netdev);
805 	if (err)
806 		return err;
807 
808 	/* finally start device */
809 	err = usb_8dev_start(priv);
810 	if (err) {
811 		if (err == -ENODEV)
812 			netif_device_detach(priv->netdev);
813 
814 		netdev_warn(netdev, "couldn't start device: %d\n",
815 			 err);
816 
817 		close_candev(netdev);
818 
819 		return err;
820 	}
821 
822 	netif_start_queue(netdev);
823 
824 	return 0;
825 }
826 
unlink_all_urbs(struct usb_8dev_priv * priv)827 static void unlink_all_urbs(struct usb_8dev_priv *priv)
828 {
829 	int i;
830 
831 	usb_kill_anchored_urbs(&priv->rx_submitted);
832 
833 	for (i = 0; i < MAX_RX_URBS; ++i)
834 		usb_free_coherent(priv->udev, RX_BUFFER_SIZE,
835 				  priv->rxbuf[i], priv->rxbuf_dma[i]);
836 
837 	usb_kill_anchored_urbs(&priv->tx_submitted);
838 	atomic_set(&priv->active_tx_urbs, 0);
839 
840 	for (i = 0; i < MAX_TX_URBS; i++)
841 		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
842 }
843 
844 /* Close USB device */
usb_8dev_close(struct net_device * netdev)845 static int usb_8dev_close(struct net_device *netdev)
846 {
847 	struct usb_8dev_priv *priv = netdev_priv(netdev);
848 	int err = 0;
849 
850 	/* Send CLOSE command to CAN controller */
851 	err = usb_8dev_cmd_close(priv);
852 	if (err)
853 		netdev_warn(netdev, "couldn't stop device");
854 
855 	priv->can.state = CAN_STATE_STOPPED;
856 
857 	netif_stop_queue(netdev);
858 
859 	/* Stop polling */
860 	unlink_all_urbs(priv);
861 
862 	close_candev(netdev);
863 
864 	return err;
865 }
866 
867 static const struct net_device_ops usb_8dev_netdev_ops = {
868 	.ndo_open = usb_8dev_open,
869 	.ndo_stop = usb_8dev_close,
870 	.ndo_start_xmit = usb_8dev_start_xmit,
871 	.ndo_change_mtu = can_change_mtu,
872 };
873 
874 static const struct ethtool_ops usb_8dev_ethtool_ops = {
875 	.get_ts_info = ethtool_op_get_ts_info,
876 };
877 
878 static const struct can_bittiming_const usb_8dev_bittiming_const = {
879 	.name = KBUILD_MODNAME,
880 	.tseg1_min = 1,
881 	.tseg1_max = 16,
882 	.tseg2_min = 1,
883 	.tseg2_max = 8,
884 	.sjw_max = 4,
885 	.brp_min = 1,
886 	.brp_max = 1024,
887 	.brp_inc = 1,
888 };
889 
890 /* Probe USB device
891  *
892  * Check device and firmware.
893  * Set supported modes and bittiming constants.
894  * Allocate some memory.
895  */
usb_8dev_probe(struct usb_interface * intf,const struct usb_device_id * id)896 static int usb_8dev_probe(struct usb_interface *intf,
897 			 const struct usb_device_id *id)
898 {
899 	struct net_device *netdev;
900 	struct usb_8dev_priv *priv;
901 	int i, err = -ENOMEM;
902 	u32 version;
903 	char buf[18];
904 	struct usb_device *usbdev = interface_to_usbdev(intf);
905 
906 	/* product id looks strange, better we also check iProduct string */
907 	if (usb_string(usbdev, usbdev->descriptor.iProduct, buf,
908 		       sizeof(buf)) > 0 && strcmp(buf, "USB2CAN converter")) {
909 		dev_info(&usbdev->dev, "ignoring: not an USB2CAN converter\n");
910 		return -ENODEV;
911 	}
912 
913 	netdev = alloc_candev(sizeof(struct usb_8dev_priv), MAX_TX_URBS);
914 	if (!netdev) {
915 		dev_err(&intf->dev, "Couldn't alloc candev\n");
916 		return -ENOMEM;
917 	}
918 
919 	priv = netdev_priv(netdev);
920 
921 	priv->udev = usbdev;
922 	priv->netdev = netdev;
923 
924 	priv->can.state = CAN_STATE_STOPPED;
925 	priv->can.clock.freq = USB_8DEV_ABP_CLOCK;
926 	priv->can.bittiming_const = &usb_8dev_bittiming_const;
927 	priv->can.do_set_mode = usb_8dev_set_mode;
928 	priv->can.do_get_berr_counter = usb_8dev_get_berr_counter;
929 	priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
930 				      CAN_CTRLMODE_LISTENONLY |
931 				      CAN_CTRLMODE_ONE_SHOT |
932 				      CAN_CTRLMODE_CC_LEN8_DLC;
933 
934 	netdev->netdev_ops = &usb_8dev_netdev_ops;
935 	netdev->ethtool_ops = &usb_8dev_ethtool_ops;
936 
937 	netdev->flags |= IFF_ECHO; /* we support local echo */
938 
939 	init_usb_anchor(&priv->rx_submitted);
940 
941 	init_usb_anchor(&priv->tx_submitted);
942 	atomic_set(&priv->active_tx_urbs, 0);
943 
944 	for (i = 0; i < MAX_TX_URBS; i++)
945 		priv->tx_contexts[i].echo_index = MAX_TX_URBS;
946 
947 	priv->cmd_msg_buffer = devm_kzalloc(&intf->dev, sizeof(struct usb_8dev_cmd_msg),
948 					    GFP_KERNEL);
949 	if (!priv->cmd_msg_buffer)
950 		goto cleanup_candev;
951 
952 	usb_set_intfdata(intf, priv);
953 
954 	SET_NETDEV_DEV(netdev, &intf->dev);
955 
956 	mutex_init(&priv->usb_8dev_cmd_lock);
957 
958 	err = register_candev(netdev);
959 	if (err) {
960 		netdev_err(netdev,
961 			"couldn't register CAN device: %d\n", err);
962 		goto cleanup_candev;
963 	}
964 
965 	err = usb_8dev_cmd_version(priv, &version);
966 	if (err) {
967 		netdev_err(netdev, "can't get firmware version\n");
968 		goto cleanup_unregister_candev;
969 	} else {
970 		netdev_info(netdev,
971 			 "firmware: %d.%d, hardware: %d.%d\n",
972 			 (version>>24) & 0xff, (version>>16) & 0xff,
973 			 (version>>8) & 0xff, version & 0xff);
974 	}
975 
976 	return 0;
977 
978 cleanup_unregister_candev:
979 	unregister_netdev(priv->netdev);
980 
981 cleanup_candev:
982 	free_candev(netdev);
983 
984 	return err;
985 
986 }
987 
988 /* Called by the usb core when driver is unloaded or device is removed */
usb_8dev_disconnect(struct usb_interface * intf)989 static void usb_8dev_disconnect(struct usb_interface *intf)
990 {
991 	struct usb_8dev_priv *priv = usb_get_intfdata(intf);
992 
993 	usb_set_intfdata(intf, NULL);
994 
995 	if (priv) {
996 		netdev_info(priv->netdev, "device disconnected\n");
997 
998 		unregister_netdev(priv->netdev);
999 		unlink_all_urbs(priv);
1000 		free_candev(priv->netdev);
1001 	}
1002 
1003 }
1004 
1005 static struct usb_driver usb_8dev_driver = {
1006 	.name =		KBUILD_MODNAME,
1007 	.probe =	usb_8dev_probe,
1008 	.disconnect =	usb_8dev_disconnect,
1009 	.id_table =	usb_8dev_table,
1010 };
1011 
1012 module_usb_driver(usb_8dev_driver);
1013 
1014 MODULE_AUTHOR("Bernd Krumboeck <krumboeck@universalnet.at>");
1015 MODULE_DESCRIPTION("CAN driver for 8 devices USB2CAN interfaces");
1016 MODULE_LICENSE("GPL v2");
1017