summaryrefslogtreecommitdiff
path: root/drivers/net/can/mscan/mscan.c
blob: 6394de840427a4b03b46dce5d0fb0786c8cf15e1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
/*
 * CAN bus driver for the alone generic (as possible as) MSCAN controller.
 *
 * Copyright (C) 2005-2006 Andrey Volkov <avolkov@varma-el.com>,
 *                         Varma Electronics Oy
 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
 * Copytight (C) 2008-2009 Pengutronix <kernel@pengutronix.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License
 * as published by the Free Software Foundation
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/if_ether.h>
#include <linux/list.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include <linux/io.h>

#include "mscan.h"

static struct can_bittiming_const mscan_bittiming_const = {
	.name = "mscan",
	.tseg1_min = 4,
	.tseg1_max = 16,
	.tseg2_min = 2,
	.tseg2_max = 8,
	.sjw_max = 4,
	.brp_min = 1,
	.brp_max = 64,
	.brp_inc = 1,
};

struct mscan_state {
	u8 mode;
	u8 canrier;
	u8 cantier;
};

static enum can_state state_map[] = {
	CAN_STATE_ERROR_ACTIVE,
	CAN_STATE_ERROR_WARNING,
	CAN_STATE_ERROR_PASSIVE,
	CAN_STATE_BUS_OFF
};

static int mscan_set_mode(struct net_device *dev, u8 mode)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	int ret = 0;
	int i;
	u8 canctl1;

	if (mode != MSCAN_NORMAL_MODE) {
		if (priv->tx_active) {
			/* Abort transfers before going to sleep */#
			out_8(&regs->cantarq, priv->tx_active);
			/* Suppress TX done interrupts */
			out_8(&regs->cantier, 0);
		}

		canctl1 = in_8(&regs->canctl1);
		if ((mode & MSCAN_SLPRQ) && !(canctl1 & MSCAN_SLPAK)) {
			out_8(&regs->canctl0,
			      in_8(&regs->canctl0) | MSCAN_SLPRQ);
			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
				if (in_8(&regs->canctl1) & MSCAN_SLPAK)
					break;
				udelay(100);
			}
			/*
			 * The mscan controller will fail to enter sleep mode,
			 * while there are irregular activities on bus, like
			 * somebody keeps retransmitting. This behavior is
			 * undocumented and seems to differ between mscan built
			 * in mpc5200b and mpc5200. We proceed in that case,
			 * since otherwise the slprq will be kept set and the
			 * controller will get stuck. NOTE: INITRQ or CSWAI
			 * will abort all active transmit actions, if still
			 * any, at once.
			 */
			if (i >= MSCAN_SET_MODE_RETRIES)
				dev_dbg(dev->dev.parent,
					"device failed to enter sleep mode. "
					"We proceed anyhow.\n");
			else
				priv->can.state = CAN_STATE_SLEEPING;
		}

		if ((mode & MSCAN_INITRQ) && !(canctl1 & MSCAN_INITAK)) {
			out_8(&regs->canctl0,
			      in_8(&regs->canctl0) | MSCAN_INITRQ);
			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
				if (in_8(&regs->canctl1) & MSCAN_INITAK)
					break;
			}
			if (i >= MSCAN_SET_MODE_RETRIES)
				ret = -ENODEV;
		}
		if (!ret)
			priv->can.state = CAN_STATE_STOPPED;

		if (mode & MSCAN_CSWAI)
			out_8(&regs->canctl0,
			      in_8(&regs->canctl0) | MSCAN_CSWAI);

	} else {
		canctl1 = in_8(&regs->canctl1);
		if (canctl1 & (MSCAN_SLPAK | MSCAN_INITAK)) {
			out_8(&regs->canctl0, in_8(&regs->canctl0) &
			      ~(MSCAN_SLPRQ | MSCAN_INITRQ));
			for (i = 0; i < MSCAN_SET_MODE_RETRIES; i++) {
				canctl1 = in_8(&regs->canctl1);
				if (!(canctl1 & (MSCAN_INITAK | MSCAN_SLPAK)))
					break;
			}
			if (i >= MSCAN_SET_MODE_RETRIES)
				ret = -ENODEV;
			else
				priv->can.state = CAN_STATE_ERROR_ACTIVE;
		}
	}
	return ret;
}

static int mscan_start(struct net_device *dev)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	u8 canrflg;
	int err;

	out_8(&regs->canrier, 0);

	INIT_LIST_HEAD(&priv->tx_head);
	priv->prev_buf_id = 0;
	priv->cur_pri = 0;
	priv->tx_active = 0;
	priv->shadow_canrier = 0;
	priv->flags = 0;

	err = mscan_set_mode(dev, MSCAN_NORMAL_MODE);
	if (err)
		return err;

	canrflg = in_8(&regs->canrflg);
	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
	priv->can.state = state_map[max(MSCAN_STATE_RX(canrflg),
				    MSCAN_STATE_TX(canrflg))];
	out_8(&regs->cantier, 0);

	/* Enable receive interrupts. */
	out_8(&regs->canrier, MSCAN_OVRIE | MSCAN_RXFIE | MSCAN_CSCIE |
	      MSCAN_RSTATE1 | MSCAN_RSTATE0 | MSCAN_TSTATE1 | MSCAN_TSTATE0);

	return 0;
}

static netdev_tx_t mscan_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct can_frame *frame = (struct can_frame *)skb->data;
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	int i, rtr, buf_id;
	u32 can_id;

	if (frame->can_dlc > 8)
		return -EINVAL;

	out_8(&regs->cantier, 0);

	i = ~priv->tx_active & MSCAN_TXE;
	buf_id = ffs(i) - 1;
	switch (hweight8(i)) {
	case 0:
		netif_stop_queue(dev);
		dev_err(dev->dev.parent, "Tx Ring full when queue awake!\n");
		return NETDEV_TX_BUSY;
	case 1:
		/*
		 * if buf_id < 3, then current frame will be send out of order,
		 * since buffer with lower id have higher priority (hell..)
		 */
		netif_stop_queue(dev);
	case 2:
		if (buf_id < priv->prev_buf_id) {
			priv->cur_pri++;
			if (priv->cur_pri == 0xff) {
				set_bit(F_TX_WAIT_ALL, &priv->flags);
				netif_stop_queue(dev);
			}
		}
		set_bit(F_TX_PROGRESS, &priv->flags);
		break;
	}
	priv->prev_buf_id = buf_id;
	out_8(&regs->cantbsel, i);

	rtr = frame->can_id & CAN_RTR_FLAG;

	if (frame->can_id & CAN_EFF_FLAG) {
		can_id = (frame->can_id & CAN_EFF_MASK) << 1;
		if (rtr)
			can_id |= 1;
		out_be16(&regs->tx.idr3_2, can_id);

		can_id >>= 16;
		can_id = (can_id & 0x7) | ((can_id << 2) & 0xffe0) | (3 << 3);
	} else {
		can_id = (frame->can_id & CAN_SFF_MASK) << 5;
		if (rtr)
			can_id |= 1 << 4;
	}
	out_be16(&regs->tx.idr1_0, can_id);

	if (!rtr) {
		void __iomem *data = &regs->tx.dsr1_0;
		u16 *payload = (u16 *)frame->data;

		/* It is safe to write into dsr[dlc+1] */
		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
			out_be16(data, *payload++);
			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
		}
	}

	out_8(&regs->tx.dlr, frame->can_dlc);
	out_8(&regs->tx.tbpr, priv->cur_pri);

	/* Start transmission. */
	out_8(&regs->cantflg, 1 << buf_id);

	if (!test_bit(F_TX_PROGRESS, &priv->flags))
		dev->trans_start = jiffies;

	list_add_tail(&priv->tx_queue[buf_id].list, &priv->tx_head);

	can_put_echo_skb(skb, dev, buf_id);

	/* Enable interrupt. */
	priv->tx_active |= 1 << buf_id;
	out_8(&regs->cantier, priv->tx_active);

	return NETDEV_TX_OK;
}

/* This function returns the old state to see where we came from */
static enum can_state check_set_state(struct net_device *dev, u8 canrflg)
{
	struct mscan_priv *priv = netdev_priv(dev);
	enum can_state state, old_state = priv->can.state;

	if (canrflg & MSCAN_CSCIF && old_state <= CAN_STATE_BUS_OFF) {
		state = state_map[max(MSCAN_STATE_RX(canrflg),
				      MSCAN_STATE_TX(canrflg))];
		priv->can.state = state;
	}
	return old_state;
}

static void mscan_get_rx_frame(struct net_device *dev, struct can_frame *frame)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	u32 can_id;
	int i;

	can_id = in_be16(&regs->rx.idr1_0);
	if (can_id & (1 << 3)) {
		frame->can_id = CAN_EFF_FLAG;
		can_id = ((can_id << 16) | in_be16(&regs->rx.idr3_2));
		can_id = ((can_id & 0xffe00000) |
			  ((can_id & 0x7ffff) << 2)) >> 2;
	} else {
		can_id >>= 4;
		frame->can_id = 0;
	}

	frame->can_id |= can_id >> 1;
	if (can_id & 1)
		frame->can_id |= CAN_RTR_FLAG;
	frame->can_dlc = in_8(&regs->rx.dlr) & 0xf;

	if (!(frame->can_id & CAN_RTR_FLAG)) {
		void __iomem *data = &regs->rx.dsr1_0;
		u16 *payload = (u16 *)frame->data;

		for (i = 0; i < (frame->can_dlc + 1) / 2; i++) {
			*payload++ = in_be16(data);
			data += 2 + _MSCAN_RESERVED_DSR_SIZE;
		}
	}

	out_8(&regs->canrflg, MSCAN_RXF);
}

static void mscan_get_err_frame(struct net_device *dev, struct can_frame *frame,
				u8 canrflg)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	struct net_device_stats *stats = &dev->stats;
	enum can_state old_state;

	dev_dbg(dev->dev.parent, "error interrupt (canrflg=%#x)\n", canrflg);
	frame->can_id = CAN_ERR_FLAG;

	if (canrflg & MSCAN_OVRIF) {
		frame->can_id |= CAN_ERR_CRTL;
		frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
		stats->rx_over_errors++;
		stats->rx_errors++;
	} else {
		frame->data[1] = 0;
	}

	old_state = check_set_state(dev, canrflg);
	/* State changed */
	if (old_state != priv->can.state) {
		switch (priv->can.state) {
		case CAN_STATE_ERROR_WARNING:
			frame->can_id |= CAN_ERR_CRTL;
			priv->can.can_stats.error_warning++;
			if ((priv->shadow_statflg & MSCAN_RSTAT_MSK) <
			    (canrflg & MSCAN_RSTAT_MSK))
				frame->data[1] |= CAN_ERR_CRTL_RX_WARNING;
			if ((priv->shadow_statflg & MSCAN_TSTAT_MSK) <
			    (canrflg & MSCAN_TSTAT_MSK))
				frame->data[1] |= CAN_ERR_CRTL_TX_WARNING;
			break;
		case CAN_STATE_ERROR_PASSIVE:
			frame->can_id |= CAN_ERR_CRTL;
			priv->can.can_stats.error_passive++;
			frame->data[1] |= CAN_ERR_CRTL_RX_PASSIVE;
			break;
		case CAN_STATE_BUS_OFF:
			frame->can_id |= CAN_ERR_BUSOFF;
			/*
			 * The MSCAN on the MPC5200 does recover from bus-off
			 * automatically. To avoid that we stop the chip doing
			 * a light-weight stop (we are in irq-context).
			 */
			out_8(&regs->cantier, 0);
			out_8(&regs->canrier, 0);
			out_8(&regs->canctl0, in_8(&regs->canctl0) |
				MSCAN_SLPRQ | MSCAN_INITRQ);
			can_bus_off(dev);
			break;
		default:
			break;
		}
	}
	priv->shadow_statflg = canrflg & MSCAN_STAT_MSK;
	frame->can_dlc = CAN_ERR_DLC;
	out_8(&regs->canrflg, MSCAN_ERR_IF);
}

static int mscan_rx_poll(struct napi_struct *napi, int quota)
{
	struct mscan_priv *priv = container_of(napi, struct mscan_priv, napi);
	struct net_device *dev = napi->dev;
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	struct net_device_stats *stats = &dev->stats;
	int npackets = 0;
	int ret = 1;
	struct sk_buff *skb;
	struct can_frame *frame;
	u8 canrflg;

	while (npackets < quota && ((canrflg = in_8(&regs->canrflg)) &
				    (MSCAN_RXF | MSCAN_ERR_IF))) {

		skb = alloc_can_skb(dev, &frame);
		if (!skb) {
			if (printk_ratelimit())
				dev_notice(dev->dev.parent, "packet dropped\n");
			stats->rx_dropped++;
			out_8(&regs->canrflg, canrflg);
			continue;
		}

		if (canrflg & MSCAN_RXF)
			mscan_get_rx_frame(dev, frame);
		else if (canrflg & MSCAN_ERR_IF)
			mscan_get_err_frame(dev, frame, canrflg);

		stats->rx_packets++;
		stats->rx_bytes += frame->can_dlc;
		npackets++;
		netif_receive_skb(skb);
	}

	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
		napi_complete(&priv->napi);
		clear_bit(F_RX_PROGRESS, &priv->flags);
		if (priv->can.state < CAN_STATE_BUS_OFF)
			out_8(&regs->canrier, priv->shadow_canrier);
		ret = 0;
	}
	return ret;
}

static irqreturn_t mscan_isr(int irq, void *dev_id)
{
	struct net_device *dev = (struct net_device *)dev_id;
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	struct net_device_stats *stats = &dev->stats;
	u8 cantier, cantflg, canrflg;
	irqreturn_t ret = IRQ_NONE;

	cantier = in_8(&regs->cantier) & MSCAN_TXE;
	cantflg = in_8(&regs->cantflg) & cantier;

	if (cantier && cantflg) {
		struct list_head *tmp, *pos;

		list_for_each_safe(pos, tmp, &priv->tx_head) {
			struct tx_queue_entry *entry =
			    list_entry(pos, struct tx_queue_entry, list);
			u8 mask = entry->mask;

			if (!(cantflg & mask))
				continue;

			out_8(&regs->cantbsel, mask);
			stats->tx_bytes += in_8(&regs->tx.dlr);
			stats->tx_packets++;
			can_get_echo_skb(dev, entry->id);
			priv->tx_active &= ~mask;
			list_del(pos);
		}

		if (list_empty(&priv->tx_head)) {
			clear_bit(F_TX_WAIT_ALL, &priv->flags);
			clear_bit(F_TX_PROGRESS, &priv->flags);
			priv->cur_pri = 0;
		} else {
			dev->trans_start = jiffies;
		}

		if (!test_bit(F_TX_WAIT_ALL, &priv->flags))
			netif_wake_queue(dev);

		out_8(&regs->cantier, priv->tx_active);
		ret = IRQ_HANDLED;
	}

	canrflg = in_8(&regs->canrflg);
	if ((canrflg & ~MSCAN_STAT_MSK) &&
	    !test_and_set_bit(F_RX_PROGRESS, &priv->flags)) {
		if (canrflg & ~MSCAN_STAT_MSK) {
			priv->shadow_canrier = in_8(&regs->canrier);
			out_8(&regs->canrier, 0);
			napi_schedule(&priv->napi);
			ret = IRQ_HANDLED;
		} else {
			clear_bit(F_RX_PROGRESS, &priv->flags);
		}
	}
	return ret;
}

static int mscan_do_set_mode(struct net_device *dev, enum can_mode mode)
{
	struct mscan_priv *priv = netdev_priv(dev);
	int ret = 0;

	if (!priv->open_time)
		return -EINVAL;

	switch (mode) {
	case CAN_MODE_SLEEP:
	case CAN_MODE_STOP:
		netif_stop_queue(dev);
		mscan_set_mode(dev,
			       (mode ==
				CAN_MODE_STOP) ? MSCAN_INIT_MODE :
			       MSCAN_SLEEP_MODE);
		break;
	case CAN_MODE_START:
		if (priv->can.state <= CAN_STATE_BUS_OFF)
			mscan_set_mode(dev, MSCAN_INIT_MODE);
		ret = mscan_start(dev);
		if (ret)
			break;
		if (netif_queue_stopped(dev))
			netif_wake_queue(dev);
		break;

	default:
		ret = -EOPNOTSUPP;
		break;
	}
	return ret;
}

static int mscan_do_set_bittiming(struct net_device *dev)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	struct can_bittiming *bt = &priv->can.bittiming;
	u8 btr0, btr1;

	btr0 = BTR0_SET_BRP(bt->brp) | BTR0_SET_SJW(bt->sjw);
	btr1 = (BTR1_SET_TSEG1(bt->prop_seg + bt->phase_seg1) |
		BTR1_SET_TSEG2(bt->phase_seg2) |
		BTR1_SET_SAM(priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES));

	dev_info(dev->dev.parent, "setting BTR0=0x%02x BTR1=0x%02x\n",
		btr0, btr1);

	out_8(&regs->canbtr0, btr0);
	out_8(&regs->canbtr1, btr1);

	return 0;
}

static int mscan_open(struct net_device *dev)
{
	int ret;
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;

	/* common open */
	ret = open_candev(dev);
	if (ret)
		return ret;

	napi_enable(&priv->napi);

	ret = request_irq(dev->irq, mscan_isr, 0, dev->name, dev);
	if (ret < 0) {
		napi_disable(&priv->napi);
		printk(KERN_ERR "%s - failed to attach interrupt\n",
		       dev->name);
		return ret;
	}

	priv->open_time = jiffies;

	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_LISTEN);

	ret = mscan_start(dev);
	if (ret)
		return ret;

	netif_start_queue(dev);

	return 0;
}

static int mscan_close(struct net_device *dev)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;

	netif_stop_queue(dev);
	napi_disable(&priv->napi);

	out_8(&regs->cantier, 0);
	out_8(&regs->canrier, 0);
	mscan_set_mode(dev, MSCAN_INIT_MODE);
	close_candev(dev);
	free_irq(dev->irq, dev);
	priv->open_time = 0;

	return 0;
}

static const struct net_device_ops mscan_netdev_ops = {
       .ndo_open               = mscan_open,
       .ndo_stop               = mscan_close,
       .ndo_start_xmit         = mscan_start_xmit,
};

int register_mscandev(struct net_device *dev, int clock_src)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	u8 ctl1;

	ctl1 = in_8(&regs->canctl1);
	if (clock_src)
		ctl1 |= MSCAN_CLKSRC;
	else
		ctl1 &= ~MSCAN_CLKSRC;

	ctl1 |= MSCAN_CANE;
	out_8(&regs->canctl1, ctl1);
	udelay(100);

	/* acceptance mask/acceptance code (accept everything) */
	out_be16(&regs->canidar1_0, 0);
	out_be16(&regs->canidar3_2, 0);
	out_be16(&regs->canidar5_4, 0);
	out_be16(&regs->canidar7_6, 0);

	out_be16(&regs->canidmr1_0, 0xffff);
	out_be16(&regs->canidmr3_2, 0xffff);
	out_be16(&regs->canidmr5_4, 0xffff);
	out_be16(&regs->canidmr7_6, 0xffff);
	/* Two 32 bit Acceptance Filters */
	out_8(&regs->canidac, MSCAN_AF_32BIT);

	mscan_set_mode(dev, MSCAN_INIT_MODE);

	return register_candev(dev);
}
EXPORT_SYMBOL_GPL(register_mscandev);

void unregister_mscandev(struct net_device *dev)
{
	struct mscan_priv *priv = netdev_priv(dev);
	struct mscan_regs *regs = (struct mscan_regs *)priv->reg_base;
	mscan_set_mode(dev, MSCAN_INIT_MODE);
	out_8(&regs->canctl1, in_8(&regs->canctl1) & ~MSCAN_CANE);
	unregister_candev(dev);
}
EXPORT_SYMBOL_GPL(unregister_mscandev);

struct net_device *alloc_mscandev(void)
{
	struct net_device *dev;
	struct mscan_priv *priv;
	int i;

	dev = alloc_candev(sizeof(struct mscan_priv), MSCAN_ECHO_SKB_MAX);
	if (!dev)
		return NULL;
	priv = netdev_priv(dev);

	dev->netdev_ops = &mscan_netdev_ops;

	dev->flags |= IFF_ECHO;	/* we support local echo */

	netif_napi_add(dev, &priv->napi, mscan_rx_poll, 8);

	priv->can.bittiming_const = &mscan_bittiming_const;
	priv->can.do_set_bittiming = mscan_do_set_bittiming;
	priv->can.do_set_mode = mscan_do_set_mode;

	for (i = 0; i < TX_QUEUE_SIZE; i++) {
		priv->tx_queue[i].id = i;
		priv->tx_queue[i].mask = 1 << i;
	}

	return dev;
}
EXPORT_SYMBOL_GPL(alloc_mscandev);

MODULE_AUTHOR("Andrey Volkov <avolkov@varma-el.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("CAN port driver for a MSCAN based chips");