xref: /openbmc/linux/drivers/net/can/usb/ems_usb.c (revision ae64438b)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * CAN driver for EMS Dr. Thomas Wuensche CPC-USB/ARM7
4  *
5  * Copyright (C) 2004-2009 EMS Dr. Thomas Wuensche
6  */
7 #include <linux/ethtool.h>
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("Sebastian Haas <haas@ems-wuensche.com>");
19 MODULE_DESCRIPTION("CAN driver for EMS Dr. Thomas Wuensche CAN/USB interfaces");
20 MODULE_LICENSE("GPL v2");
21 
22 /* Control-Values for CPC_Control() Command Subject Selection */
23 #define CONTR_CAN_MESSAGE 0x04
24 #define CONTR_CAN_STATE   0x0C
25 #define CONTR_BUS_ERROR   0x1C
26 
27 /* Control Command Actions */
28 #define CONTR_CONT_OFF 0
29 #define CONTR_CONT_ON  1
30 #define CONTR_ONCE     2
31 
32 /* Messages from CPC to PC */
33 #define CPC_MSG_TYPE_CAN_FRAME       1  /* CAN data frame */
34 #define CPC_MSG_TYPE_RTR_FRAME       8  /* CAN remote frame */
35 #define CPC_MSG_TYPE_CAN_PARAMS      12 /* Actual CAN parameters */
36 #define CPC_MSG_TYPE_CAN_STATE       14 /* CAN state message */
37 #define CPC_MSG_TYPE_EXT_CAN_FRAME   16 /* Extended CAN data frame */
38 #define CPC_MSG_TYPE_EXT_RTR_FRAME   17 /* Extended remote frame */
39 #define CPC_MSG_TYPE_CONTROL         19 /* change interface behavior */
40 #define CPC_MSG_TYPE_CONFIRM         20 /* command processed confirmation */
41 #define CPC_MSG_TYPE_OVERRUN         21 /* overrun events */
42 #define CPC_MSG_TYPE_CAN_FRAME_ERROR 23 /* detected bus errors */
43 #define CPC_MSG_TYPE_ERR_COUNTER     25 /* RX/TX error counter */
44 
45 /* Messages from the PC to the CPC interface  */
46 #define CPC_CMD_TYPE_CAN_FRAME     1   /* CAN data frame */
47 #define CPC_CMD_TYPE_CONTROL       3   /* control of interface behavior */
48 #define CPC_CMD_TYPE_CAN_PARAMS    6   /* set CAN parameters */
49 #define CPC_CMD_TYPE_RTR_FRAME     13  /* CAN remote frame */
50 #define CPC_CMD_TYPE_CAN_STATE     14  /* CAN state message */
51 #define CPC_CMD_TYPE_EXT_CAN_FRAME 15  /* Extended CAN data frame */
52 #define CPC_CMD_TYPE_EXT_RTR_FRAME 16  /* Extended CAN remote frame */
53 #define CPC_CMD_TYPE_CAN_EXIT      200 /* exit the CAN */
54 
55 #define CPC_CMD_TYPE_INQ_ERR_COUNTER 25 /* request the CAN error counters */
56 #define CPC_CMD_TYPE_CLEAR_MSG_QUEUE 8  /* clear CPC_MSG queue */
57 #define CPC_CMD_TYPE_CLEAR_CMD_QUEUE 28 /* clear CPC_CMD queue */
58 
59 #define CPC_CC_TYPE_SJA1000 2 /* Philips basic CAN controller */
60 
61 #define CPC_CAN_ECODE_ERRFRAME 0x01 /* Ecode type */
62 
63 /* Overrun types */
64 #define CPC_OVR_EVENT_CAN       0x01
65 #define CPC_OVR_EVENT_CANSTATE  0x02
66 #define CPC_OVR_EVENT_BUSERROR  0x04
67 
68 /*
69  * If the CAN controller lost a message we indicate it with the highest bit
70  * set in the count field.
71  */
72 #define CPC_OVR_HW 0x80
73 
74 /* Size of the "struct ems_cpc_msg" without the union */
75 #define CPC_MSG_HEADER_LEN   11
76 #define CPC_CAN_MSG_MIN_SIZE 5
77 
78 /* Define these values to match your devices */
79 #define USB_CPCUSB_VENDOR_ID 0x12D6
80 
81 #define USB_CPCUSB_ARM7_PRODUCT_ID 0x0444
82 
83 /* Mode register NXP LPC2119/SJA1000 CAN Controller */
84 #define SJA1000_MOD_NORMAL 0x00
85 #define SJA1000_MOD_RM     0x01
86 
87 /* ECC register NXP LPC2119/SJA1000 CAN Controller */
88 #define SJA1000_ECC_SEG   0x1F
89 #define SJA1000_ECC_DIR   0x20
90 #define SJA1000_ECC_ERR   0x06
91 #define SJA1000_ECC_BIT   0x00
92 #define SJA1000_ECC_FORM  0x40
93 #define SJA1000_ECC_STUFF 0x80
94 #define SJA1000_ECC_MASK  0xc0
95 
96 /* Status register content */
97 #define SJA1000_SR_BS 0x80
98 #define SJA1000_SR_ES 0x40
99 
100 #define SJA1000_DEFAULT_OUTPUT_CONTROL 0xDA
101 
102 /*
103  * The device actually uses a 16MHz clock to generate the CAN clock
104  * but it expects SJA1000 bit settings based on 8MHz (is internally
105  * converted).
106  */
107 #define EMS_USB_ARM7_CLOCK 8000000
108 
109 #define CPC_TX_QUEUE_TRIGGER_LOW	25
110 #define CPC_TX_QUEUE_TRIGGER_HIGH	35
111 
112 /*
113  * CAN-Message representation in a CPC_MSG. Message object type is
114  * CPC_MSG_TYPE_CAN_FRAME or CPC_MSG_TYPE_RTR_FRAME or
115  * CPC_MSG_TYPE_EXT_CAN_FRAME or CPC_MSG_TYPE_EXT_RTR_FRAME.
116  */
117 struct cpc_can_msg {
118 	__le32 id;
119 	u8 length;
120 	u8 msg[8];
121 };
122 
123 /* Representation of the CAN parameters for the SJA1000 controller */
124 struct cpc_sja1000_params {
125 	u8 mode;
126 	u8 acc_code0;
127 	u8 acc_code1;
128 	u8 acc_code2;
129 	u8 acc_code3;
130 	u8 acc_mask0;
131 	u8 acc_mask1;
132 	u8 acc_mask2;
133 	u8 acc_mask3;
134 	u8 btr0;
135 	u8 btr1;
136 	u8 outp_contr;
137 };
138 
139 /* CAN params message representation */
140 struct cpc_can_params {
141 	u8 cc_type;
142 
143 	/* Will support M16C CAN controller in the future */
144 	union {
145 		struct cpc_sja1000_params sja1000;
146 	} cc_params;
147 };
148 
149 /* Structure for confirmed message handling */
150 struct cpc_confirm {
151 	u8 error; /* error code */
152 };
153 
154 /* Structure for overrun conditions */
155 struct cpc_overrun {
156 	u8 event;
157 	u8 count;
158 };
159 
160 /* SJA1000 CAN errors (compatible to NXP LPC2119) */
161 struct cpc_sja1000_can_error {
162 	u8 ecc;
163 	u8 rxerr;
164 	u8 txerr;
165 };
166 
167 /* structure for CAN error conditions */
168 struct cpc_can_error {
169 	u8 ecode;
170 
171 	struct {
172 		u8 cc_type;
173 
174 		/* Other controllers may also provide error code capture regs */
175 		union {
176 			struct cpc_sja1000_can_error sja1000;
177 		} regs;
178 	} cc;
179 };
180 
181 /*
182  * Structure containing RX/TX error counter. This structure is used to request
183  * the values of the CAN controllers TX and RX error counter.
184  */
185 struct cpc_can_err_counter {
186 	u8 rx;
187 	u8 tx;
188 };
189 
190 /* Main message type used between library and application */
191 struct __packed ems_cpc_msg {
192 	u8 type;	/* type of message */
193 	u8 length;	/* length of data within union 'msg' */
194 	u8 msgid;	/* confirmation handle */
195 	__le32 ts_sec;	/* timestamp in seconds */
196 	__le32 ts_nsec;	/* timestamp in nano seconds */
197 
198 	union __packed {
199 		u8 generic[64];
200 		struct cpc_can_msg can_msg;
201 		struct cpc_can_params can_params;
202 		struct cpc_confirm confirmation;
203 		struct cpc_overrun overrun;
204 		struct cpc_can_error error;
205 		struct cpc_can_err_counter err_counter;
206 		u8 can_state;
207 	} msg;
208 };
209 
210 /*
211  * Table of devices that work with this driver
212  * NOTE: This driver supports only CPC-USB/ARM7 (LPC2119) yet.
213  */
214 static struct usb_device_id ems_usb_table[] = {
215 	{USB_DEVICE(USB_CPCUSB_VENDOR_ID, USB_CPCUSB_ARM7_PRODUCT_ID)},
216 	{} /* Terminating entry */
217 };
218 
219 MODULE_DEVICE_TABLE(usb, ems_usb_table);
220 
221 #define RX_BUFFER_SIZE      64
222 #define CPC_HEADER_SIZE     4
223 #define INTR_IN_BUFFER_SIZE 4
224 
225 #define MAX_RX_URBS 10
226 #define MAX_TX_URBS 10
227 
228 struct ems_usb;
229 
230 struct ems_tx_urb_context {
231 	struct ems_usb *dev;
232 
233 	u32 echo_index;
234 };
235 
236 struct ems_usb {
237 	struct can_priv can; /* must be the first member */
238 
239 	struct sk_buff *echo_skb[MAX_TX_URBS];
240 
241 	struct usb_device *udev;
242 	struct net_device *netdev;
243 
244 	atomic_t active_tx_urbs;
245 	struct usb_anchor tx_submitted;
246 	struct ems_tx_urb_context tx_contexts[MAX_TX_URBS];
247 
248 	struct usb_anchor rx_submitted;
249 
250 	struct urb *intr_urb;
251 
252 	u8 *tx_msg_buffer;
253 
254 	u8 *intr_in_buffer;
255 	unsigned int free_slots; /* remember number of available slots */
256 
257 	struct ems_cpc_msg active_params; /* active controller parameters */
258 	void *rxbuf[MAX_RX_URBS];
259 	dma_addr_t rxbuf_dma[MAX_RX_URBS];
260 };
261 
ems_usb_read_interrupt_callback(struct urb * urb)262 static void ems_usb_read_interrupt_callback(struct urb *urb)
263 {
264 	struct ems_usb *dev = urb->context;
265 	struct net_device *netdev = dev->netdev;
266 	int err;
267 
268 	if (!netif_device_present(netdev))
269 		return;
270 
271 	switch (urb->status) {
272 	case 0:
273 		dev->free_slots = dev->intr_in_buffer[1];
274 		if (dev->free_slots > CPC_TX_QUEUE_TRIGGER_HIGH &&
275 		    netif_queue_stopped(netdev))
276 			netif_wake_queue(netdev);
277 		break;
278 
279 	case -ECONNRESET: /* unlink */
280 	case -ENOENT:
281 	case -EPIPE:
282 	case -EPROTO:
283 	case -ESHUTDOWN:
284 		return;
285 
286 	default:
287 		netdev_info(netdev, "Rx interrupt aborted %d\n", urb->status);
288 		break;
289 	}
290 
291 	err = usb_submit_urb(urb, GFP_ATOMIC);
292 
293 	if (err == -ENODEV)
294 		netif_device_detach(netdev);
295 	else if (err)
296 		netdev_err(netdev, "failed resubmitting intr urb: %d\n", err);
297 }
298 
ems_usb_rx_can_msg(struct ems_usb * dev,struct ems_cpc_msg * msg)299 static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
300 {
301 	struct can_frame *cf;
302 	struct sk_buff *skb;
303 	int i;
304 	struct net_device_stats *stats = &dev->netdev->stats;
305 
306 	skb = alloc_can_skb(dev->netdev, &cf);
307 	if (skb == NULL)
308 		return;
309 
310 	cf->can_id = le32_to_cpu(msg->msg.can_msg.id);
311 	cf->len = can_cc_dlc2len(msg->msg.can_msg.length & 0xF);
312 
313 	if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME ||
314 	    msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
315 		cf->can_id |= CAN_EFF_FLAG;
316 
317 	if (msg->type == CPC_MSG_TYPE_RTR_FRAME ||
318 	    msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
319 		cf->can_id |= CAN_RTR_FLAG;
320 	} else {
321 		for (i = 0; i < cf->len; i++)
322 			cf->data[i] = msg->msg.can_msg.msg[i];
323 
324 		stats->rx_bytes += cf->len;
325 	}
326 	stats->rx_packets++;
327 
328 	netif_rx(skb);
329 }
330 
ems_usb_rx_err(struct ems_usb * dev,struct ems_cpc_msg * msg)331 static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
332 {
333 	struct can_frame *cf;
334 	struct sk_buff *skb;
335 	struct net_device_stats *stats = &dev->netdev->stats;
336 
337 	skb = alloc_can_err_skb(dev->netdev, &cf);
338 	if (skb == NULL)
339 		return;
340 
341 	if (msg->type == CPC_MSG_TYPE_CAN_STATE) {
342 		u8 state = msg->msg.can_state;
343 
344 		if (state & SJA1000_SR_BS) {
345 			dev->can.state = CAN_STATE_BUS_OFF;
346 			cf->can_id |= CAN_ERR_BUSOFF;
347 
348 			dev->can.can_stats.bus_off++;
349 			can_bus_off(dev->netdev);
350 		} else if (state & SJA1000_SR_ES) {
351 			dev->can.state = CAN_STATE_ERROR_WARNING;
352 			dev->can.can_stats.error_warning++;
353 		} else {
354 			dev->can.state = CAN_STATE_ERROR_ACTIVE;
355 			dev->can.can_stats.error_passive++;
356 		}
357 	} else if (msg->type == CPC_MSG_TYPE_CAN_FRAME_ERROR) {
358 		u8 ecc = msg->msg.error.cc.regs.sja1000.ecc;
359 		u8 txerr = msg->msg.error.cc.regs.sja1000.txerr;
360 		u8 rxerr = msg->msg.error.cc.regs.sja1000.rxerr;
361 
362 		/* bus error interrupt */
363 		dev->can.can_stats.bus_error++;
364 		stats->rx_errors++;
365 
366 		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
367 
368 		switch (ecc & SJA1000_ECC_MASK) {
369 		case SJA1000_ECC_BIT:
370 			cf->data[2] |= CAN_ERR_PROT_BIT;
371 			break;
372 		case SJA1000_ECC_FORM:
373 			cf->data[2] |= CAN_ERR_PROT_FORM;
374 			break;
375 		case SJA1000_ECC_STUFF:
376 			cf->data[2] |= CAN_ERR_PROT_STUFF;
377 			break;
378 		default:
379 			cf->data[3] = ecc & SJA1000_ECC_SEG;
380 			break;
381 		}
382 
383 		/* Error occurred during transmission? */
384 		if ((ecc & SJA1000_ECC_DIR) == 0)
385 			cf->data[2] |= CAN_ERR_PROT_TX;
386 
387 		if (dev->can.state == CAN_STATE_ERROR_WARNING ||
388 		    dev->can.state == CAN_STATE_ERROR_PASSIVE) {
389 			cf->can_id |= CAN_ERR_CRTL;
390 			cf->data[1] = (txerr > rxerr) ?
391 			    CAN_ERR_CRTL_TX_PASSIVE : CAN_ERR_CRTL_RX_PASSIVE;
392 		}
393 	} else if (msg->type == CPC_MSG_TYPE_OVERRUN) {
394 		cf->can_id |= CAN_ERR_CRTL;
395 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
396 
397 		stats->rx_over_errors++;
398 		stats->rx_errors++;
399 	}
400 
401 	netif_rx(skb);
402 }
403 
404 /*
405  * callback for bulk IN urb
406  */
ems_usb_read_bulk_callback(struct urb * urb)407 static void ems_usb_read_bulk_callback(struct urb *urb)
408 {
409 	struct ems_usb *dev = urb->context;
410 	struct net_device *netdev;
411 	int retval;
412 
413 	netdev = dev->netdev;
414 
415 	if (!netif_device_present(netdev))
416 		return;
417 
418 	switch (urb->status) {
419 	case 0: /* success */
420 		break;
421 
422 	case -ENOENT:
423 		return;
424 
425 	default:
426 		netdev_info(netdev, "Rx URB aborted (%d)\n", urb->status);
427 		goto resubmit_urb;
428 	}
429 
430 	if (urb->actual_length > CPC_HEADER_SIZE) {
431 		struct ems_cpc_msg *msg;
432 		u8 *ibuf = urb->transfer_buffer;
433 		u8 msg_count, start;
434 
435 		msg_count = ibuf[0] & ~0x80;
436 
437 		start = CPC_HEADER_SIZE;
438 
439 		while (msg_count) {
440 			msg = (struct ems_cpc_msg *)&ibuf[start];
441 
442 			switch (msg->type) {
443 			case CPC_MSG_TYPE_CAN_STATE:
444 				/* Process CAN state changes */
445 				ems_usb_rx_err(dev, msg);
446 				break;
447 
448 			case CPC_MSG_TYPE_CAN_FRAME:
449 			case CPC_MSG_TYPE_EXT_CAN_FRAME:
450 			case CPC_MSG_TYPE_RTR_FRAME:
451 			case CPC_MSG_TYPE_EXT_RTR_FRAME:
452 				ems_usb_rx_can_msg(dev, msg);
453 				break;
454 
455 			case CPC_MSG_TYPE_CAN_FRAME_ERROR:
456 				/* Process errorframe */
457 				ems_usb_rx_err(dev, msg);
458 				break;
459 
460 			case CPC_MSG_TYPE_OVERRUN:
461 				/* Message lost while receiving */
462 				ems_usb_rx_err(dev, msg);
463 				break;
464 			}
465 
466 			start += CPC_MSG_HEADER_LEN + msg->length;
467 			msg_count--;
468 
469 			if (start > urb->transfer_buffer_length) {
470 				netdev_err(netdev, "format error\n");
471 				break;
472 			}
473 		}
474 	}
475 
476 resubmit_urb:
477 	usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
478 			  urb->transfer_buffer, RX_BUFFER_SIZE,
479 			  ems_usb_read_bulk_callback, dev);
480 
481 	retval = usb_submit_urb(urb, GFP_ATOMIC);
482 
483 	if (retval == -ENODEV)
484 		netif_device_detach(netdev);
485 	else if (retval)
486 		netdev_err(netdev,
487 			   "failed resubmitting read bulk urb: %d\n", retval);
488 }
489 
490 /*
491  * callback for bulk IN urb
492  */
ems_usb_write_bulk_callback(struct urb * urb)493 static void ems_usb_write_bulk_callback(struct urb *urb)
494 {
495 	struct ems_tx_urb_context *context = urb->context;
496 	struct ems_usb *dev;
497 	struct net_device *netdev;
498 
499 	BUG_ON(!context);
500 
501 	dev = context->dev;
502 	netdev = dev->netdev;
503 
504 	/* free up our allocated buffer */
505 	usb_free_coherent(urb->dev, urb->transfer_buffer_length,
506 			  urb->transfer_buffer, urb->transfer_dma);
507 
508 	atomic_dec(&dev->active_tx_urbs);
509 
510 	if (!netif_device_present(netdev))
511 		return;
512 
513 	if (urb->status)
514 		netdev_info(netdev, "Tx URB aborted (%d)\n", urb->status);
515 
516 	netif_trans_update(netdev);
517 
518 	/* transmission complete interrupt */
519 	netdev->stats.tx_packets++;
520 	netdev->stats.tx_bytes += can_get_echo_skb(netdev, context->echo_index,
521 						   NULL);
522 
523 	/* Release context */
524 	context->echo_index = MAX_TX_URBS;
525 
526 }
527 
528 /*
529  * Send the given CPC command synchronously
530  */
ems_usb_command_msg(struct ems_usb * dev,struct ems_cpc_msg * msg)531 static int ems_usb_command_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
532 {
533 	int actual_length;
534 
535 	/* Copy payload */
536 	memcpy(&dev->tx_msg_buffer[CPC_HEADER_SIZE], msg,
537 	       msg->length + CPC_MSG_HEADER_LEN);
538 
539 	/* Clear header */
540 	memset(&dev->tx_msg_buffer[0], 0, CPC_HEADER_SIZE);
541 
542 	return usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 2),
543 			    &dev->tx_msg_buffer[0],
544 			    msg->length + CPC_MSG_HEADER_LEN + CPC_HEADER_SIZE,
545 			    &actual_length, 1000);
546 }
547 
548 /*
549  * Change CAN controllers' mode register
550  */
ems_usb_write_mode(struct ems_usb * dev,u8 mode)551 static int ems_usb_write_mode(struct ems_usb *dev, u8 mode)
552 {
553 	dev->active_params.msg.can_params.cc_params.sja1000.mode = mode;
554 
555 	return ems_usb_command_msg(dev, &dev->active_params);
556 }
557 
558 /*
559  * Send a CPC_Control command to change behaviour when interface receives a CAN
560  * message, bus error or CAN state changed notifications.
561  */
ems_usb_control_cmd(struct ems_usb * dev,u8 val)562 static int ems_usb_control_cmd(struct ems_usb *dev, u8 val)
563 {
564 	struct ems_cpc_msg cmd;
565 
566 	cmd.type = CPC_CMD_TYPE_CONTROL;
567 	cmd.length = CPC_MSG_HEADER_LEN + 1;
568 
569 	cmd.msgid = 0;
570 
571 	cmd.msg.generic[0] = val;
572 
573 	return ems_usb_command_msg(dev, &cmd);
574 }
575 
576 /*
577  * Start interface
578  */
ems_usb_start(struct ems_usb * dev)579 static int ems_usb_start(struct ems_usb *dev)
580 {
581 	struct net_device *netdev = dev->netdev;
582 	int err, i;
583 
584 	dev->intr_in_buffer[0] = 0;
585 	dev->free_slots = 50; /* initial size */
586 
587 	for (i = 0; i < MAX_RX_URBS; i++) {
588 		struct urb *urb = NULL;
589 		u8 *buf = NULL;
590 		dma_addr_t buf_dma;
591 
592 		/* create a URB, and a buffer for it */
593 		urb = usb_alloc_urb(0, GFP_KERNEL);
594 		if (!urb) {
595 			err = -ENOMEM;
596 			break;
597 		}
598 
599 		buf = usb_alloc_coherent(dev->udev, RX_BUFFER_SIZE, GFP_KERNEL,
600 					 &buf_dma);
601 		if (!buf) {
602 			netdev_err(netdev, "No memory left for USB buffer\n");
603 			usb_free_urb(urb);
604 			err = -ENOMEM;
605 			break;
606 		}
607 
608 		urb->transfer_dma = buf_dma;
609 
610 		usb_fill_bulk_urb(urb, dev->udev, usb_rcvbulkpipe(dev->udev, 2),
611 				  buf, RX_BUFFER_SIZE,
612 				  ems_usb_read_bulk_callback, dev);
613 		urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
614 		usb_anchor_urb(urb, &dev->rx_submitted);
615 
616 		err = usb_submit_urb(urb, GFP_KERNEL);
617 		if (err) {
618 			usb_unanchor_urb(urb);
619 			usb_free_coherent(dev->udev, RX_BUFFER_SIZE, buf,
620 					  urb->transfer_dma);
621 			usb_free_urb(urb);
622 			break;
623 		}
624 
625 		dev->rxbuf[i] = buf;
626 		dev->rxbuf_dma[i] = buf_dma;
627 
628 		/* Drop reference, USB core will take care of freeing it */
629 		usb_free_urb(urb);
630 	}
631 
632 	/* Did we submit any URBs */
633 	if (i == 0) {
634 		netdev_warn(netdev, "couldn't setup read URBs\n");
635 		return err;
636 	}
637 
638 	/* Warn if we've couldn't transmit all the URBs */
639 	if (i < MAX_RX_URBS)
640 		netdev_warn(netdev, "rx performance may be slow\n");
641 
642 	/* Setup and start interrupt URB */
643 	usb_fill_int_urb(dev->intr_urb, dev->udev,
644 			 usb_rcvintpipe(dev->udev, 1),
645 			 dev->intr_in_buffer,
646 			 INTR_IN_BUFFER_SIZE,
647 			 ems_usb_read_interrupt_callback, dev, 1);
648 
649 	err = usb_submit_urb(dev->intr_urb, GFP_KERNEL);
650 	if (err) {
651 		netdev_warn(netdev, "intr URB submit failed: %d\n", err);
652 
653 		return err;
654 	}
655 
656 	/* CPC-USB will transfer received message to host */
657 	err = ems_usb_control_cmd(dev, CONTR_CAN_MESSAGE | CONTR_CONT_ON);
658 	if (err)
659 		goto failed;
660 
661 	/* CPC-USB will transfer CAN state changes to host */
662 	err = ems_usb_control_cmd(dev, CONTR_CAN_STATE | CONTR_CONT_ON);
663 	if (err)
664 		goto failed;
665 
666 	/* CPC-USB will transfer bus errors to host */
667 	err = ems_usb_control_cmd(dev, CONTR_BUS_ERROR | CONTR_CONT_ON);
668 	if (err)
669 		goto failed;
670 
671 	err = ems_usb_write_mode(dev, SJA1000_MOD_NORMAL);
672 	if (err)
673 		goto failed;
674 
675 	dev->can.state = CAN_STATE_ERROR_ACTIVE;
676 
677 	return 0;
678 
679 failed:
680 	netdev_warn(netdev, "couldn't submit control: %d\n", err);
681 
682 	return err;
683 }
684 
unlink_all_urbs(struct ems_usb * dev)685 static void unlink_all_urbs(struct ems_usb *dev)
686 {
687 	int i;
688 
689 	usb_unlink_urb(dev->intr_urb);
690 
691 	usb_kill_anchored_urbs(&dev->rx_submitted);
692 
693 	for (i = 0; i < MAX_RX_URBS; ++i)
694 		usb_free_coherent(dev->udev, RX_BUFFER_SIZE,
695 				  dev->rxbuf[i], dev->rxbuf_dma[i]);
696 
697 	usb_kill_anchored_urbs(&dev->tx_submitted);
698 	atomic_set(&dev->active_tx_urbs, 0);
699 
700 	for (i = 0; i < MAX_TX_URBS; i++)
701 		dev->tx_contexts[i].echo_index = MAX_TX_URBS;
702 }
703 
ems_usb_open(struct net_device * netdev)704 static int ems_usb_open(struct net_device *netdev)
705 {
706 	struct ems_usb *dev = netdev_priv(netdev);
707 	int err;
708 
709 	err = ems_usb_write_mode(dev, SJA1000_MOD_RM);
710 	if (err)
711 		return err;
712 
713 	/* common open */
714 	err = open_candev(netdev);
715 	if (err)
716 		return err;
717 
718 	/* finally start device */
719 	err = ems_usb_start(dev);
720 	if (err) {
721 		if (err == -ENODEV)
722 			netif_device_detach(dev->netdev);
723 
724 		netdev_warn(netdev, "couldn't start device: %d\n", err);
725 
726 		close_candev(netdev);
727 
728 		return err;
729 	}
730 
731 
732 	netif_start_queue(netdev);
733 
734 	return 0;
735 }
736 
ems_usb_start_xmit(struct sk_buff * skb,struct net_device * netdev)737 static netdev_tx_t ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
738 {
739 	struct ems_usb *dev = netdev_priv(netdev);
740 	struct ems_tx_urb_context *context = NULL;
741 	struct net_device_stats *stats = &netdev->stats;
742 	struct can_frame *cf = (struct can_frame *)skb->data;
743 	struct ems_cpc_msg *msg;
744 	struct urb *urb;
745 	u8 *buf;
746 	int i, err;
747 	size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
748 			+ sizeof(struct cpc_can_msg);
749 
750 	if (can_dev_dropped_skb(netdev, skb))
751 		return NETDEV_TX_OK;
752 
753 	/* create a URB, and a buffer for it, and copy the data to the URB */
754 	urb = usb_alloc_urb(0, GFP_ATOMIC);
755 	if (!urb)
756 		goto nomem;
757 
758 	buf = usb_alloc_coherent(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
759 	if (!buf) {
760 		netdev_err(netdev, "No memory left for USB buffer\n");
761 		usb_free_urb(urb);
762 		goto nomem;
763 	}
764 
765 	msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
766 
767 	msg->msg.can_msg.id = cpu_to_le32(cf->can_id & CAN_ERR_MASK);
768 	msg->msg.can_msg.length = cf->len;
769 
770 	if (cf->can_id & CAN_RTR_FLAG) {
771 		msg->type = cf->can_id & CAN_EFF_FLAG ?
772 			CPC_CMD_TYPE_EXT_RTR_FRAME : CPC_CMD_TYPE_RTR_FRAME;
773 
774 		msg->length = CPC_CAN_MSG_MIN_SIZE;
775 	} else {
776 		msg->type = cf->can_id & CAN_EFF_FLAG ?
777 			CPC_CMD_TYPE_EXT_CAN_FRAME : CPC_CMD_TYPE_CAN_FRAME;
778 
779 		for (i = 0; i < cf->len; i++)
780 			msg->msg.can_msg.msg[i] = cf->data[i];
781 
782 		msg->length = CPC_CAN_MSG_MIN_SIZE + cf->len;
783 	}
784 
785 	for (i = 0; i < MAX_TX_URBS; i++) {
786 		if (dev->tx_contexts[i].echo_index == MAX_TX_URBS) {
787 			context = &dev->tx_contexts[i];
788 			break;
789 		}
790 	}
791 
792 	/*
793 	 * May never happen! When this happens we'd more URBs in flight as
794 	 * allowed (MAX_TX_URBS).
795 	 */
796 	if (!context) {
797 		usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
798 		usb_free_urb(urb);
799 
800 		netdev_warn(netdev, "couldn't find free context\n");
801 
802 		return NETDEV_TX_BUSY;
803 	}
804 
805 	context->dev = dev;
806 	context->echo_index = i;
807 
808 	usb_fill_bulk_urb(urb, dev->udev, usb_sndbulkpipe(dev->udev, 2), buf,
809 			  size, ems_usb_write_bulk_callback, context);
810 	urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
811 	usb_anchor_urb(urb, &dev->tx_submitted);
812 
813 	can_put_echo_skb(skb, netdev, context->echo_index, 0);
814 
815 	atomic_inc(&dev->active_tx_urbs);
816 
817 	err = usb_submit_urb(urb, GFP_ATOMIC);
818 	if (unlikely(err)) {
819 		can_free_echo_skb(netdev, context->echo_index, NULL);
820 
821 		usb_unanchor_urb(urb);
822 		usb_free_coherent(dev->udev, size, buf, urb->transfer_dma);
823 
824 		atomic_dec(&dev->active_tx_urbs);
825 
826 		if (err == -ENODEV) {
827 			netif_device_detach(netdev);
828 		} else {
829 			netdev_warn(netdev, "failed tx_urb %d\n", err);
830 
831 			stats->tx_dropped++;
832 		}
833 	} else {
834 		netif_trans_update(netdev);
835 
836 		/* Slow down tx path */
837 		if (atomic_read(&dev->active_tx_urbs) >= MAX_TX_URBS ||
838 		    dev->free_slots < CPC_TX_QUEUE_TRIGGER_LOW) {
839 			netif_stop_queue(netdev);
840 		}
841 	}
842 
843 	/*
844 	 * Release our reference to this URB, the USB core will eventually free
845 	 * it entirely.
846 	 */
847 	usb_free_urb(urb);
848 
849 	return NETDEV_TX_OK;
850 
851 nomem:
852 	dev_kfree_skb(skb);
853 	stats->tx_dropped++;
854 
855 	return NETDEV_TX_OK;
856 }
857 
ems_usb_close(struct net_device * netdev)858 static int ems_usb_close(struct net_device *netdev)
859 {
860 	struct ems_usb *dev = netdev_priv(netdev);
861 
862 	/* Stop polling */
863 	unlink_all_urbs(dev);
864 
865 	netif_stop_queue(netdev);
866 
867 	/* Set CAN controller to reset mode */
868 	if (ems_usb_write_mode(dev, SJA1000_MOD_RM))
869 		netdev_warn(netdev, "couldn't stop device");
870 
871 	close_candev(netdev);
872 
873 	return 0;
874 }
875 
876 static const struct net_device_ops ems_usb_netdev_ops = {
877 	.ndo_open = ems_usb_open,
878 	.ndo_stop = ems_usb_close,
879 	.ndo_start_xmit = ems_usb_start_xmit,
880 	.ndo_change_mtu = can_change_mtu,
881 };
882 
883 static const struct ethtool_ops ems_usb_ethtool_ops = {
884 	.get_ts_info = ethtool_op_get_ts_info,
885 };
886 
887 static const struct can_bittiming_const ems_usb_bittiming_const = {
888 	.name = KBUILD_MODNAME,
889 	.tseg1_min = 1,
890 	.tseg1_max = 16,
891 	.tseg2_min = 1,
892 	.tseg2_max = 8,
893 	.sjw_max = 4,
894 	.brp_min = 1,
895 	.brp_max = 64,
896 	.brp_inc = 1,
897 };
898 
ems_usb_set_mode(struct net_device * netdev,enum can_mode mode)899 static int ems_usb_set_mode(struct net_device *netdev, enum can_mode mode)
900 {
901 	struct ems_usb *dev = netdev_priv(netdev);
902 
903 	switch (mode) {
904 	case CAN_MODE_START:
905 		if (ems_usb_write_mode(dev, SJA1000_MOD_NORMAL))
906 			netdev_warn(netdev, "couldn't start device");
907 
908 		if (netif_queue_stopped(netdev))
909 			netif_wake_queue(netdev);
910 		break;
911 
912 	default:
913 		return -EOPNOTSUPP;
914 	}
915 
916 	return 0;
917 }
918 
ems_usb_set_bittiming(struct net_device * netdev)919 static int ems_usb_set_bittiming(struct net_device *netdev)
920 {
921 	struct ems_usb *dev = netdev_priv(netdev);
922 	struct can_bittiming *bt = &dev->can.bittiming;
923 	u8 btr0, btr1;
924 
925 	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
926 	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
927 		(((bt->phase_seg2 - 1) & 0x7) << 4);
928 	if (dev->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
929 		btr1 |= 0x80;
930 
931 	netdev_info(netdev, "setting BTR0=0x%02x BTR1=0x%02x\n", btr0, btr1);
932 
933 	dev->active_params.msg.can_params.cc_params.sja1000.btr0 = btr0;
934 	dev->active_params.msg.can_params.cc_params.sja1000.btr1 = btr1;
935 
936 	return ems_usb_command_msg(dev, &dev->active_params);
937 }
938 
init_params_sja1000(struct ems_cpc_msg * msg)939 static void init_params_sja1000(struct ems_cpc_msg *msg)
940 {
941 	struct cpc_sja1000_params *sja1000 =
942 		&msg->msg.can_params.cc_params.sja1000;
943 
944 	msg->type = CPC_CMD_TYPE_CAN_PARAMS;
945 	msg->length = sizeof(struct cpc_can_params);
946 	msg->msgid = 0;
947 
948 	msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
949 
950 	/* Acceptance filter open */
951 	sja1000->acc_code0 = 0x00;
952 	sja1000->acc_code1 = 0x00;
953 	sja1000->acc_code2 = 0x00;
954 	sja1000->acc_code3 = 0x00;
955 
956 	/* Acceptance filter open */
957 	sja1000->acc_mask0 = 0xFF;
958 	sja1000->acc_mask1 = 0xFF;
959 	sja1000->acc_mask2 = 0xFF;
960 	sja1000->acc_mask3 = 0xFF;
961 
962 	sja1000->btr0 = 0;
963 	sja1000->btr1 = 0;
964 
965 	sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
966 	sja1000->mode = SJA1000_MOD_RM;
967 }
968 
969 /*
970  * probe function for new CPC-USB devices
971  */
ems_usb_probe(struct usb_interface * intf,const struct usb_device_id * id)972 static int ems_usb_probe(struct usb_interface *intf,
973 			 const struct usb_device_id *id)
974 {
975 	struct net_device *netdev;
976 	struct ems_usb *dev;
977 	int i, err = -ENOMEM;
978 
979 	netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
980 	if (!netdev) {
981 		dev_err(&intf->dev, "ems_usb: Couldn't alloc candev\n");
982 		return -ENOMEM;
983 	}
984 
985 	dev = netdev_priv(netdev);
986 
987 	dev->udev = interface_to_usbdev(intf);
988 	dev->netdev = netdev;
989 
990 	dev->can.state = CAN_STATE_STOPPED;
991 	dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
992 	dev->can.bittiming_const = &ems_usb_bittiming_const;
993 	dev->can.do_set_bittiming = ems_usb_set_bittiming;
994 	dev->can.do_set_mode = ems_usb_set_mode;
995 	dev->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;
996 
997 	netdev->netdev_ops = &ems_usb_netdev_ops;
998 	netdev->ethtool_ops = &ems_usb_ethtool_ops;
999 
1000 	netdev->flags |= IFF_ECHO; /* we support local echo */
1001 
1002 	init_usb_anchor(&dev->rx_submitted);
1003 
1004 	init_usb_anchor(&dev->tx_submitted);
1005 	atomic_set(&dev->active_tx_urbs, 0);
1006 
1007 	for (i = 0; i < MAX_TX_URBS; i++)
1008 		dev->tx_contexts[i].echo_index = MAX_TX_URBS;
1009 
1010 	dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
1011 	if (!dev->intr_urb)
1012 		goto cleanup_candev;
1013 
1014 	dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
1015 	if (!dev->intr_in_buffer)
1016 		goto cleanup_intr_urb;
1017 
1018 	dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
1019 				     sizeof(struct ems_cpc_msg), GFP_KERNEL);
1020 	if (!dev->tx_msg_buffer)
1021 		goto cleanup_intr_in_buffer;
1022 
1023 	usb_set_intfdata(intf, dev);
1024 
1025 	SET_NETDEV_DEV(netdev, &intf->dev);
1026 
1027 	init_params_sja1000(&dev->active_params);
1028 
1029 	err = ems_usb_command_msg(dev, &dev->active_params);
1030 	if (err) {
1031 		netdev_err(netdev, "couldn't initialize controller: %d\n", err);
1032 		goto cleanup_tx_msg_buffer;
1033 	}
1034 
1035 	err = register_candev(netdev);
1036 	if (err) {
1037 		netdev_err(netdev, "couldn't register CAN device: %d\n", err);
1038 		goto cleanup_tx_msg_buffer;
1039 	}
1040 
1041 	return 0;
1042 
1043 cleanup_tx_msg_buffer:
1044 	kfree(dev->tx_msg_buffer);
1045 
1046 cleanup_intr_in_buffer:
1047 	kfree(dev->intr_in_buffer);
1048 
1049 cleanup_intr_urb:
1050 	usb_free_urb(dev->intr_urb);
1051 
1052 cleanup_candev:
1053 	free_candev(netdev);
1054 
1055 	return err;
1056 }
1057 
1058 /*
1059  * called by the usb core when the device is removed from the system
1060  */
ems_usb_disconnect(struct usb_interface * intf)1061 static void ems_usb_disconnect(struct usb_interface *intf)
1062 {
1063 	struct ems_usb *dev = usb_get_intfdata(intf);
1064 
1065 	usb_set_intfdata(intf, NULL);
1066 
1067 	if (dev) {
1068 		unregister_netdev(dev->netdev);
1069 
1070 		unlink_all_urbs(dev);
1071 
1072 		usb_free_urb(dev->intr_urb);
1073 
1074 		kfree(dev->intr_in_buffer);
1075 		kfree(dev->tx_msg_buffer);
1076 
1077 		free_candev(dev->netdev);
1078 	}
1079 }
1080 
1081 /* usb specific object needed to register this driver with the usb subsystem */
1082 static struct usb_driver ems_usb_driver = {
1083 	.name = KBUILD_MODNAME,
1084 	.probe = ems_usb_probe,
1085 	.disconnect = ems_usb_disconnect,
1086 	.id_table = ems_usb_table,
1087 };
1088 
1089 module_usb_driver(ems_usb_driver);
1090