aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/can/bfin_can.c
blob: 8a0b515b33ea57c5804f1c9a82b774be8aadee7f (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
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
/*
 * Blackfin On-Chip CAN Driver
 *
 * Copyright 2004-2009 Analog Devices Inc.
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/errno.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/platform_device.h>

#include <linux/can/dev.h>
#include <linux/can/error.h>

#include <asm/bfin_can.h>
#include <asm/portmux.h>

#define DRV_NAME "bfin_can"
#define BFIN_CAN_TIMEOUT 100
#define TX_ECHO_SKB_MAX  1

/*
 * bfin can private data
 */
struct bfin_can_priv {
	struct can_priv can;	/* must be the first member */
	struct net_device *dev;
	void __iomem *membase;
	int rx_irq;
	int tx_irq;
	int err_irq;
	unsigned short *pin_list;
};

/*
 * bfin can timing parameters
 */
static const struct can_bittiming_const bfin_can_bittiming_const = {
	.name = DRV_NAME,
	.tseg1_min = 1,
	.tseg1_max = 16,
	.tseg2_min = 1,
	.tseg2_max = 8,
	.sjw_max = 4,
	/*
	 * Although the BRP field can be set to any value, it is recommended
	 * that the value be greater than or equal to 4, as restrictions
	 * apply to the bit timing configuration when BRP is less than 4.
	 */
	.brp_min = 4,
	.brp_max = 1024,
	.brp_inc = 1,
};

static int bfin_can_set_bittiming(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_bittiming *bt = &priv->can.bittiming;
	u16 clk, timing;

	clk = bt->brp - 1;
	timing = ((bt->sjw - 1) << 8) | (bt->prop_seg + bt->phase_seg1 - 1) |
		((bt->phase_seg2 - 1) << 4);

	/*
	 * If the SAM bit is set, the input signal is oversampled three times
	 * at the SCLK rate.
	 */
	if (priv->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
		timing |= SAM;

	bfin_write(&reg->clock, clk);
	bfin_write(&reg->timing, timing);

	netdev_info(dev, "setting CLOCK=0x%04x TIMING=0x%04x\n", clk, timing);

	return 0;
}

static void bfin_can_set_reset_mode(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;
	int i;

	/* disable interrupts */
	bfin_write(&reg->mbim1, 0);
	bfin_write(&reg->mbim2, 0);
	bfin_write(&reg->gim, 0);

	/* reset can and enter configuration mode */
	bfin_write(&reg->control, SRS | CCR);
	SSYNC();
	bfin_write(&reg->control, CCR);
	SSYNC();
	while (!(bfin_read(&reg->control) & CCA)) {
		udelay(10);
		if (--timeout == 0) {
			netdev_err(dev, "fail to enter configuration mode\n");
			BUG();
		}
	}

	/*
	 * All mailbox configurations are marked as inactive
	 * by writing to CAN Mailbox Configuration Registers 1 and 2
	 * For all bits: 0 - Mailbox disabled, 1 - Mailbox enabled
	 */
	bfin_write(&reg->mc1, 0);
	bfin_write(&reg->mc2, 0);

	/* Set Mailbox Direction */
	bfin_write(&reg->md1, 0xFFFF);   /* mailbox 1-16 are RX */
	bfin_write(&reg->md2, 0);   /* mailbox 17-32 are TX */

	/* RECEIVE_STD_CHL */
	for (i = 0; i < 2; i++) {
		bfin_write(&reg->chl[RECEIVE_STD_CHL + i].id0, 0);
		bfin_write(&reg->chl[RECEIVE_STD_CHL + i].id1, AME);
		bfin_write(&reg->chl[RECEIVE_STD_CHL + i].dlc, 0);
		bfin_write(&reg->msk[RECEIVE_STD_CHL + i].amh, 0x1FFF);
		bfin_write(&reg->msk[RECEIVE_STD_CHL + i].aml, 0xFFFF);
	}

	/* RECEIVE_EXT_CHL */
	for (i = 0; i < 2; i++) {
		bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].id0, 0);
		bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].id1, AME | IDE);
		bfin_write(&reg->chl[RECEIVE_EXT_CHL + i].dlc, 0);
		bfin_write(&reg->msk[RECEIVE_EXT_CHL + i].amh, 0x1FFF);
		bfin_write(&reg->msk[RECEIVE_EXT_CHL + i].aml, 0xFFFF);
	}

	bfin_write(&reg->mc2, BIT(TRANSMIT_CHL - 16));
	bfin_write(&reg->mc1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
	SSYNC();

	priv->can.state = CAN_STATE_STOPPED;
}

static void bfin_can_set_normal_mode(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;

	/*
	 * leave configuration mode
	 */
	bfin_write(&reg->control, bfin_read(&reg->control) & ~CCR);

	while (bfin_read(&reg->status) & CCA) {
		udelay(10);
		if (--timeout == 0) {
			netdev_err(dev, "fail to leave configuration mode\n");
			BUG();
		}
	}

	/*
	 * clear _All_  tx and rx interrupts
	 */
	bfin_write(&reg->mbtif1, 0xFFFF);
	bfin_write(&reg->mbtif2, 0xFFFF);
	bfin_write(&reg->mbrif1, 0xFFFF);
	bfin_write(&reg->mbrif2, 0xFFFF);

	/*
	 * clear global interrupt status register
	 */
	bfin_write(&reg->gis, 0x7FF); /* overwrites with '1' */

	/*
	 * Initialize Interrupts
	 * - set bits in the mailbox interrupt mask register
	 * - global interrupt mask
	 */
	bfin_write(&reg->mbim1, BIT(RECEIVE_STD_CHL) + BIT(RECEIVE_EXT_CHL));
	bfin_write(&reg->mbim2, BIT(TRANSMIT_CHL - 16));

	bfin_write(&reg->gim, EPIM | BOIM | RMLIM);
	SSYNC();
}

static void bfin_can_start(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);

	/* enter reset mode */
	if (priv->can.state != CAN_STATE_STOPPED)
		bfin_can_set_reset_mode(dev);

	/* leave reset mode */
	bfin_can_set_normal_mode(dev);
}

static int bfin_can_set_mode(struct net_device *dev, enum can_mode mode)
{
	switch (mode) {
	case CAN_MODE_START:
		bfin_can_start(dev);
		if (netif_queue_stopped(dev))
			netif_wake_queue(dev);
		break;

	default:
		return -EOPNOTSUPP;
	}

	return 0;
}

static int bfin_can_get_berr_counter(const struct net_device *dev,
				     struct can_berr_counter *bec)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;

	u16 cec = bfin_read(&reg->cec);

	bec->txerr = cec >> 8;
	bec->rxerr = cec;

	return 0;
}

static int bfin_can_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_frame *cf = (struct can_frame *)skb->data;
	u8 dlc = cf->can_dlc;
	canid_t id = cf->can_id;
	u8 *data = cf->data;
	u16 val;
	int i;

	if (can_dropped_invalid_skb(dev, skb))
		return NETDEV_TX_OK;

	netif_stop_queue(dev);

	/* fill id */
	if (id & CAN_EFF_FLAG) {
		bfin_write(&reg->chl[TRANSMIT_CHL].id0, id);
		val = ((id & 0x1FFF0000) >> 16) | IDE;
	} else
		val = (id << 2);
	if (id & CAN_RTR_FLAG)
		val |= RTR;
	bfin_write(&reg->chl[TRANSMIT_CHL].id1, val | AME);

	/* fill payload */
	for (i = 0; i < 8; i += 2) {
		val = ((7 - i) < dlc ? (data[7 - i]) : 0) +
			((6 - i) < dlc ? (data[6 - i] << 8) : 0);
		bfin_write(&reg->chl[TRANSMIT_CHL].data[i], val);
	}

	/* fill data length code */
	bfin_write(&reg->chl[TRANSMIT_CHL].dlc, dlc);

	can_put_echo_skb(skb, dev, 0);

	/* set transmit request */
	bfin_write(&reg->trs2, BIT(TRANSMIT_CHL - 16));

	return 0;
}

static void bfin_can_rx(struct net_device *dev, u16 isrc)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct net_device_stats *stats = &dev->stats;
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct can_frame *cf;
	struct sk_buff *skb;
	int obj;
	int i;
	u16 val;

	skb = alloc_can_skb(dev, &cf);
	if (skb == NULL)
		return;

	/* get id */
	if (isrc & BIT(RECEIVE_EXT_CHL)) {
		/* extended frame format (EFF) */
		cf->can_id = ((bfin_read(&reg->chl[RECEIVE_EXT_CHL].id1)
			     & 0x1FFF) << 16)
			     + bfin_read(&reg->chl[RECEIVE_EXT_CHL].id0);
		cf->can_id |= CAN_EFF_FLAG;
		obj = RECEIVE_EXT_CHL;
	} else {
		/* standard frame format (SFF) */
		cf->can_id = (bfin_read(&reg->chl[RECEIVE_STD_CHL].id1)
			     & 0x1ffc) >> 2;
		obj = RECEIVE_STD_CHL;
	}
	if (bfin_read(&reg->chl[obj].id1) & RTR)
		cf->can_id |= CAN_RTR_FLAG;

	/* get data length code */
	cf->can_dlc = get_can_dlc(bfin_read(&reg->chl[obj].dlc) & 0xF);

	/* get payload */
	for (i = 0; i < 8; i += 2) {
		val = bfin_read(&reg->chl[obj].data[i]);
		cf->data[7 - i] = (7 - i) < cf->can_dlc ? val : 0;
		cf->data[6 - i] = (6 - i) < cf->can_dlc ? (val >> 8) : 0;
	}

	netif_rx(skb);

	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;
}

static int bfin_can_err(struct net_device *dev, u16 isrc, u16 status)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct net_device_stats *stats = &dev->stats;
	struct can_frame *cf;
	struct sk_buff *skb;
	enum can_state state = priv->can.state;

	skb = alloc_can_err_skb(dev, &cf);
	if (skb == NULL)
		return -ENOMEM;

	if (isrc & RMLIS) {
		/* data overrun interrupt */
		netdev_dbg(dev, "data overrun interrupt\n");
		cf->can_id |= CAN_ERR_CRTL;
		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
		stats->rx_over_errors++;
		stats->rx_errors++;
	}

	if (isrc & BOIS) {
		netdev_dbg(dev, "bus-off mode interrupt\n");
		state = CAN_STATE_BUS_OFF;
		cf->can_id |= CAN_ERR_BUSOFF;
		can_bus_off(dev);
	}

	if (isrc & EPIS) {
		/* error passive interrupt */
		netdev_dbg(dev, "error passive interrupt\n");
		state = CAN_STATE_ERROR_PASSIVE;
	}

	if ((isrc & EWTIS) || (isrc & EWRIS)) {
		netdev_dbg(dev, "Error Warning Transmit/Receive Interrupt\n");
		state = CAN_STATE_ERROR_WARNING;
	}

	if (state != priv->can.state && (state == CAN_STATE_ERROR_WARNING ||
				state == CAN_STATE_ERROR_PASSIVE)) {
		u16 cec = bfin_read(&reg->cec);
		u8 rxerr = cec;
		u8 txerr = cec >> 8;

		cf->can_id |= CAN_ERR_CRTL;
		if (state == CAN_STATE_ERROR_WARNING) {
			priv->can.can_stats.error_warning++;
			cf->data[1] = (txerr > rxerr) ?
				CAN_ERR_CRTL_TX_WARNING :
				CAN_ERR_CRTL_RX_WARNING;
		} else {
			priv->can.can_stats.error_passive++;
			cf->data[1] = (txerr > rxerr) ?
				CAN_ERR_CRTL_TX_PASSIVE :
				CAN_ERR_CRTL_RX_PASSIVE;
		}
	}

	if (status) {
		priv->can.can_stats.bus_error++;

		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;

		if (status & BEF)
			cf->data[2] |= CAN_ERR_PROT_BIT;
		else if (status & FER)
			cf->data[2] |= CAN_ERR_PROT_FORM;
		else if (status & SER)
			cf->data[2] |= CAN_ERR_PROT_STUFF;
		else
			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
	}

	priv->can.state = state;

	netif_rx(skb);

	stats->rx_packets++;
	stats->rx_bytes += cf->can_dlc;

	return 0;
}

static irqreturn_t bfin_can_interrupt(int irq, void *dev_id)
{
	struct net_device *dev = dev_id;
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	struct net_device_stats *stats = &dev->stats;
	u16 status, isrc;

	if ((irq == priv->tx_irq) && bfin_read(&reg->mbtif2)) {
		/* transmission complete interrupt */
		bfin_write(&reg->mbtif2, 0xFFFF);
		stats->tx_packets++;
		stats->tx_bytes += bfin_read(&reg->chl[TRANSMIT_CHL].dlc);
		can_get_echo_skb(dev, 0);
		netif_wake_queue(dev);
	} else if ((irq == priv->rx_irq) && bfin_read(&reg->mbrif1)) {
		/* receive interrupt */
		isrc = bfin_read(&reg->mbrif1);
		bfin_write(&reg->mbrif1, 0xFFFF);
		bfin_can_rx(dev, isrc);
	} else if ((irq == priv->err_irq) && bfin_read(&reg->gis)) {
		/* error interrupt */
		isrc = bfin_read(&reg->gis);
		status = bfin_read(&reg->esr);
		bfin_write(&reg->gis, 0x7FF);
		bfin_can_err(dev, isrc, status);
	} else {
		return IRQ_NONE;
	}

	return IRQ_HANDLED;
}

static int bfin_can_open(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);
	int err;

	/* set chip into reset mode */
	bfin_can_set_reset_mode(dev);

	/* common open */
	err = open_candev(dev);
	if (err)
		goto exit_open;

	/* register interrupt handler */
	err = request_irq(priv->rx_irq, &bfin_can_interrupt, 0,
			"bfin-can-rx", dev);
	if (err)
		goto exit_rx_irq;
	err = request_irq(priv->tx_irq, &bfin_can_interrupt, 0,
			"bfin-can-tx", dev);
	if (err)
		goto exit_tx_irq;
	err = request_irq(priv->err_irq, &bfin_can_interrupt, 0,
			"bfin-can-err", dev);
	if (err)
		goto exit_err_irq;

	bfin_can_start(dev);

	netif_start_queue(dev);

	return 0;

exit_err_irq:
	free_irq(priv->tx_irq, dev);
exit_tx_irq:
	free_irq(priv->rx_irq, dev);
exit_rx_irq:
	close_candev(dev);
exit_open:
	return err;
}

static int bfin_can_close(struct net_device *dev)
{
	struct bfin_can_priv *priv = netdev_priv(dev);

	netif_stop_queue(dev);
	bfin_can_set_reset_mode(dev);

	close_candev(dev);

	free_irq(priv->rx_irq, dev);
	free_irq(priv->tx_irq, dev);
	free_irq(priv->err_irq, dev);

	return 0;
}

static struct net_device *alloc_bfin_candev(void)
{
	struct net_device *dev;
	struct bfin_can_priv *priv;

	dev = alloc_candev(sizeof(*priv), TX_ECHO_SKB_MAX);
	if (!dev)
		return NULL;

	priv = netdev_priv(dev);

	priv->dev = dev;
	priv->can.bittiming_const = &bfin_can_bittiming_const;
	priv->can.do_set_bittiming = bfin_can_set_bittiming;
	priv->can.do_set_mode = bfin_can_set_mode;
	priv->can.do_get_berr_counter = bfin_can_get_berr_counter;
	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES;

	return dev;
}

static const struct net_device_ops bfin_can_netdev_ops = {
	.ndo_open               = bfin_can_open,
	.ndo_stop               = bfin_can_close,
	.ndo_start_xmit         = bfin_can_start_xmit,
};

static int bfin_can_probe(struct platform_device *pdev)
{
	int err;
	struct net_device *dev;
	struct bfin_can_priv *priv;
	struct resource *res_mem, *rx_irq, *tx_irq, *err_irq;
	unsigned short *pdata;

	pdata = dev_get_platdata(&pdev->dev);
	if (!pdata) {
		dev_err(&pdev->dev, "No platform data provided!\n");
		err = -EINVAL;
		goto exit;
	}

	res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	rx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	tx_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 1);
	err_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
	if (!res_mem || !rx_irq || !tx_irq || !err_irq) {
		err = -EINVAL;
		goto exit;
	}

	if (!request_mem_region(res_mem->start, resource_size(res_mem),
				dev_name(&pdev->dev))) {
		err = -EBUSY;
		goto exit;
	}

	/* request peripheral pins */
	err = peripheral_request_list(pdata, dev_name(&pdev->dev));
	if (err)
		goto exit_mem_release;

	dev = alloc_bfin_candev();
	if (!dev) {
		err = -ENOMEM;
		goto exit_peri_pin_free;
	}

	priv = netdev_priv(dev);
	priv->membase = (void __iomem *)res_mem->start;
	priv->rx_irq = rx_irq->start;
	priv->tx_irq = tx_irq->start;
	priv->err_irq = err_irq->start;
	priv->pin_list = pdata;
	priv->can.clock.freq = get_sclk();

	platform_set_drvdata(pdev, dev);
	SET_NETDEV_DEV(dev, &pdev->dev);

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

	bfin_can_set_reset_mode(dev);

	err = register_candev(dev);
	if (err) {
		dev_err(&pdev->dev, "registering failed (err=%d)\n", err);
		goto exit_candev_free;
	}

	dev_info(&pdev->dev,
		"%s device registered"
		"(&reg_base=%p, rx_irq=%d, tx_irq=%d, err_irq=%d, sclk=%d)\n",
		DRV_NAME, priv->membase, priv->rx_irq,
		priv->tx_irq, priv->err_irq, priv->can.clock.freq);
	return 0;

exit_candev_free:
	free_candev(dev);
exit_peri_pin_free:
	peripheral_free_list(pdata);
exit_mem_release:
	release_mem_region(res_mem->start, resource_size(res_mem));
exit:
	return err;
}

static int bfin_can_remove(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct resource *res;

	bfin_can_set_reset_mode(dev);

	unregister_candev(dev);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, resource_size(res));

	peripheral_free_list(priv->pin_list);

	free_candev(dev);
	return 0;
}

#ifdef CONFIG_PM
static int bfin_can_suspend(struct platform_device *pdev, pm_message_t mesg)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;
	int timeout = BFIN_CAN_TIMEOUT;

	if (netif_running(dev)) {
		/* enter sleep mode */
		bfin_write(&reg->control, bfin_read(&reg->control) | SMR);
		SSYNC();
		while (!(bfin_read(&reg->intr) & SMACK)) {
			udelay(10);
			if (--timeout == 0) {
				netdev_err(dev, "fail to enter sleep mode\n");
				BUG();
			}
		}
	}

	return 0;
}

static int bfin_can_resume(struct platform_device *pdev)
{
	struct net_device *dev = platform_get_drvdata(pdev);
	struct bfin_can_priv *priv = netdev_priv(dev);
	struct bfin_can_regs __iomem *reg = priv->membase;

	if (netif_running(dev)) {
		/* leave sleep mode */
		bfin_write(&reg->intr, 0);
		SSYNC();
	}

	return 0;
}
#else
#define bfin_can_suspend NULL
#define bfin_can_resume NULL
#endif	/* CONFIG_PM */

static struct platform_driver bfin_can_driver = {
	.probe = bfin_can_probe,
	.remove = bfin_can_remove,
	.suspend = bfin_can_suspend,
	.resume = bfin_can_resume,
	.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
	},
};

module_platform_driver(bfin_can_driver);

MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Blackfin on-chip CAN netdevice driver");
MODULE_ALIAS("platform:" DRV_NAME);