summaryrefslogtreecommitdiff
path: root/drivers/net/can/apalis-tk1-k20-can.c
blob: 1df9fae96cc3efbc46477080aeba97fe29d0aff9 (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
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
/*
 * Copyright 2016-2017 Toradex AG
 * Dominik Sliwa <dominik.sliwa@toradex.com>
 *
 * CAN bus driver for Apalis TK1 K20 CAN Controller over MFD device
 * based on MCP251x CAN driver
 *
 * This program is free software; you can redistribute it and/or modify it under
 * the terms of the GNU General Public License version 2 as published by the
 * Free Software Foundation.
 */

#include <linux/can/core.h>
#include <linux/can/dev.h>
#include <linux/can/led.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/freezer.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/apalis-tk1-k20.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/uaccess.h>

/* Buffer size required for the largest transfer (i.e., reading a
 * frame)
 */
#define CAN_FRAME_MAX_LEN	8
#define CAN_HEADER_MAX_LEN	5
#define CAN_TRANSFER_BUF_LEN	(CAN_HEADER_MAX_LEN + CAN_FRAME_MAX_LEN)
#define CAN_FRAME_MAX_BITS	128
#define CAN_MAX_CONTINUOUS_READ	8

#define MB_DLC_OFF	0
#define MB_EID_OFF	1
#define MB_RTR_SHIFT	4
#define MB_IDE_SHIFT	5
#define MB_DLC_MASK	0xF
#define MB_EID_LEN	4

#define CANCTRL_MODMASK	0x03
#define CANCTRL_INTMASK	0x38
#define CANCTRL_INTEN	BIT(2)
#define CANINTF_RX	BIT(3)
#define CANINTF_TX	BIT(4)
#define CANINTF_ERR	BIT(5)

#define EFLG_EWARN	0x01
#define EFLG_RXWAR	0x02
#define EFLG_TXWAR	0x04
#define EFLG_RXEP	0x08
#define EFLG_TXEP	0x10
#define EFLG_TXBO	0x20
#define EFLG_RXOVR	0x40

#define TX_ECHO_SKB_MAX	1

#define K20_CAN_MAX_ID	1

#define DEVICE_NAME "apalis-tk1-k20-can"

static const struct can_bittiming_const apalis_tk1_k20_can_bittiming_const = {
	.name = "tk1-k20-can",
	.tseg1_min = 3,
	.tseg1_max = 16,
	.tseg2_min = 2,
	.tseg2_max = 8,
	.sjw_max = 4,
	.brp_min = 1,
	.brp_max = 64,
	.brp_inc = 1,
};

struct apalis_tk1_k20_priv {
	struct can_priv can;
	struct net_device *net;
	struct apalis_tk1_k20_regmap *apalis_tk1_k20;
	struct apalis_tk1_k20_can_platform_data *pdata;

	struct sk_buff *tx_skb;
	int tx_len;

	struct workqueue_struct *wq;
	struct work_struct tx_work;
	struct work_struct restart_work;
	struct mutex apalis_tk1_k20_can_lock;

	int force_quit;
	int after_suspend;
#define AFTER_SUSPEND_UP	1
#define AFTER_SUSPEND_DOWN	2
#define AFTER_SUSPEND_RESTART	4
	int restart_tx;
};

static void apalis_tk1_k20_can_clean(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	if (priv->tx_skb || priv->tx_len)
		net->stats.tx_errors++;
	if (priv->tx_skb)
		dev_kfree_skb(priv->tx_skb);
	if (priv->tx_len)
		can_free_echo_skb(priv->net, 0);
	priv->tx_skb = NULL;
	priv->tx_len = 0;
}

static void apalis_tk1_k20_can_hw_tx_frame(struct net_device *net, u8 *buf,
					   int len, int tx_buf_idx)
{
	/* TODO: Implement multiple TX buffer handling */
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	apalis_tk1_k20_reg_write_bulk(priv->apalis_tk1_k20,
				      APALIS_TK1_K20_CAN_OUT_BUF
				      + APALIS_TK1_K20_CAN_DEV_OFFSET(
				      priv->pdata->id), buf, len);
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
}

static void apalis_tk1_k20_can_hw_tx(struct net_device *net,
				     struct can_frame *frame, int tx_buf_idx)
{
	u8 buf[CAN_TRANSFER_BUF_LEN];

	buf[MB_DLC_OFF] = frame->can_dlc;
	memcpy(buf + MB_EID_OFF, &frame->can_id, MB_EID_LEN);
	memcpy(buf + CAN_HEADER_MAX_LEN, frame->data, frame->can_dlc);

	apalis_tk1_k20_can_hw_tx_frame(net, buf, frame->can_dlc
			+ CAN_HEADER_MAX_LEN, tx_buf_idx);
}

static void apalis_tk1_k20_can_hw_rx_frame(struct net_device *net, u8 *buf,
					   int buf_idx)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	apalis_tk1_k20_lock(priv->apalis_tk1_k20);

	apalis_tk1_k20_reg_read_bulk(priv->apalis_tk1_k20,
				     APALIS_TK1_K20_CAN_OUT_BUF
				     + APALIS_TK1_K20_CAN_DEV_OFFSET(
				     priv->pdata->id), buf,
				     CAN_TRANSFER_BUF_LEN);
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
}

static u32 apalis_tk1_k20_can_available_rx_frames(struct net_device *net)
{
	u32 frame_cnt = 0;
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	int ret;

	apalis_tk1_k20_lock(priv->apalis_tk1_k20);

	ret = apalis_tk1_k20_reg_read(priv->apalis_tk1_k20,
				      APALIS_TK1_K20_CAN_IN_BUF_CNT
				      + APALIS_TK1_K20_CAN_DEV_OFFSET(
				      priv->pdata->id),	&frame_cnt);
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);

	return (ret == 0) ? frame_cnt : 0;
}

static void apalis_tk1_k20_can_hw_rx(struct net_device *net, int buf_idx)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	struct sk_buff *skb;
	struct can_frame *frame;
	u32 available_frames = 0;
	u8 buf[CAN_TRANSFER_BUF_LEN];

	skb = alloc_can_skb(priv->net, &frame);
	if (!skb) {
		dev_err(&net->dev, "cannot allocate RX skb\n");
		priv->net->stats.rx_dropped++;
		return;
	}

	available_frames = apalis_tk1_k20_can_available_rx_frames(net);

	while ((available_frames > 0)) {
		apalis_tk1_k20_can_hw_rx_frame(net, buf, buf_idx);
		memcpy(&frame->can_id, buf + MB_EID_OFF, MB_EID_LEN);
		/* Data length */
		frame->can_dlc = get_can_dlc(buf[MB_DLC_OFF]);
		memcpy(frame->data, buf + CAN_HEADER_MAX_LEN, frame->can_dlc);

		priv->net->stats.rx_packets++;
		priv->net->stats.rx_bytes += frame->can_dlc;

		can_led_event(priv->net, CAN_LED_EVENT_RX);

		netif_rx_ni(skb);
		available_frames--;
	}
}

static netdev_tx_t apalis_tk1_k20_can_hard_start_xmit(struct sk_buff *skb,
						      struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	if (priv->tx_skb || priv->tx_len) {
		dev_warn(&net->dev, "hard_xmit called while TX busy\n");
		return NETDEV_TX_BUSY;
	}

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

	netif_stop_queue(net);
	priv->tx_skb = skb;
	queue_work(priv->wq, &priv->tx_work);

	return NETDEV_TX_OK;
}

static int apalis_tk1_k20_can_do_set_mode(struct net_device *net,
					  enum can_mode mode)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	switch (mode) {
	case CAN_MODE_START:
		apalis_tk1_k20_can_clean(net);
		/* We have to delay work since I/O may sleep */
		priv->can.state = CAN_STATE_ERROR_ACTIVE;
		priv->restart_tx = 1;
		if (priv->can.restart_ms == 0)
			priv->after_suspend = AFTER_SUSPEND_RESTART;
		queue_work(priv->wq, &priv->restart_work);
		break;
	default:
		return -EOPNOTSUPP;
	}

	return 0;
}

static int apalis_tk1_k20_can_set_normal_mode(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);

	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	/* Enable interrupts */
	apalis_tk1_k20_reg_rmw(priv->apalis_tk1_k20, APALIS_TK1_K20_CANREG
			       + APALIS_TK1_K20_CAN_DEV_OFFSET(
			       priv->pdata->id),
			       CANCTRL_INTEN, CANCTRL_INTEN);

	if (priv->can.ctrlmode & CAN_CTRLMODE_LOOPBACK) {
		/* Put device into loopback mode */
		apalis_tk1_k20_reg_rmw(priv->apalis_tk1_k20,
				       APALIS_TK1_K20_CANREG
				       + APALIS_TK1_K20_CAN_DEV_OFFSET(
				       priv->pdata->id), CANCTRL_MODMASK,
				       CAN_CTRLMODE_LOOPBACK);
	} else if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
		/* Put device into listen-only mode */
		apalis_tk1_k20_reg_rmw(priv->apalis_tk1_k20,
				       APALIS_TK1_K20_CANREG
				       + APALIS_TK1_K20_CAN_DEV_OFFSET(
				       priv->pdata->id), CANCTRL_MODMASK,
				       CAN_CTRLMODE_LISTENONLY);
	} else {
		/* Put device into normal mode */
		apalis_tk1_k20_reg_rmw(priv->apalis_tk1_k20,
				       APALIS_TK1_K20_CANREG
				       + APALIS_TK1_K20_CAN_DEV_OFFSET(
				       priv->pdata->id), CANCTRL_MODMASK,
				       0x00);
	}
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	priv->can.state = CAN_STATE_ERROR_ACTIVE;
	return 0;
}

static int apalis_tk1_k20_can_do_set_bittiming(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	struct can_bittiming *bt = &priv->can.bittiming;

	if ((bt->bitrate / APALIS_TK1_CAN_CLK_UNIT) > 0xFF)
		return -EINVAL;

	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	apalis_tk1_k20_reg_write(priv->apalis_tk1_k20,
				 APALIS_TK1_K20_CAN_BAUD_REG
				 + APALIS_TK1_K20_CAN_DEV_OFFSET(
				 priv->pdata->id), (bt->bitrate /
				 APALIS_TK1_CAN_CLK_UNIT) & 0xFF);
	apalis_tk1_k20_reg_write(priv->apalis_tk1_k20,
				 APALIS_TK1_K20_CAN_BIT_1
				 + APALIS_TK1_K20_CAN_DEV_OFFSET(
				 priv->pdata->id),
				 ((bt->sjw & 0x3) << 6) |
				  ((bt->phase_seg2 & 0x7) << 3) |
				  (bt->phase_seg1 & 0x7));
	apalis_tk1_k20_reg_write(priv->apalis_tk1_k20,
				 APALIS_TK1_K20_CAN_BIT_2
				 + APALIS_TK1_K20_CAN_DEV_OFFSET(
				 priv->pdata->id),
				 (bt->prop_seg & 0x7));
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	dev_dbg(priv->apalis_tk1_k20->dev, "Setting CAN%d bitrate " \
		"to %d (0x%X * 6.25kHz)\n", priv->pdata->id, bt->bitrate,
		(bt->bitrate / APALIS_TK1_CAN_CLK_UNIT) & 0xFF);
	dev_dbg(priv->apalis_tk1_k20->dev, "Setting CAN%d bit timing " \
		"RJW = %d, PSEG1 = %d, PSEG2 = %d, PROPSEG = %d\n",
		priv->pdata->id, bt->sjw, bt->phase_seg1,
		bt->phase_seg2, bt->prop_seg);
	dev_dbg(priv->apalis_tk1_k20->dev, "Setting CAN%d bit timing " \
		"bitrate = %d\n", priv->pdata->id, bt->bitrate);

	return 0;
}

static int apalis_tk1_k20_can_setup(struct net_device *net,
				    struct apalis_tk1_k20_priv *priv)
{
	apalis_tk1_k20_can_do_set_bittiming(net);

	return 0;
}

static int apalis_tk1_k20_can_hw_reset(struct net_device *net)
{
	return 0;
}

static void apalis_tk1_k20_can_open_clean(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	struct apalis_tk1_k20_can_platform_data *pdata = priv->pdata;

	if (pdata->id == 0)
		apalis_tk1_k20_irq_free(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN0_IRQ, priv);
	if (pdata->id == 1)
		apalis_tk1_k20_irq_free(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN1_IRQ, priv);
	close_candev(net);
}

static int apalis_tk1_k20_can_stop(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	struct apalis_tk1_k20_can_platform_data *pdata = priv->pdata;

	close_candev(net);

	priv->force_quit = 1;
	if (pdata->id == 0)
		apalis_tk1_k20_irq_free(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN0_IRQ, priv);
	if (pdata->id == 1)
		apalis_tk1_k20_irq_free(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN1_IRQ, priv);
	destroy_workqueue(priv->wq);
	priv->wq = NULL;

	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	if (pdata->id == 0)
		apalis_tk1_k20_irq_mask(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN0_IRQ);
	if (pdata->id == 1)
		apalis_tk1_k20_irq_mask(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN1_IRQ);
	/* Disable and clear pending interrupts */
	priv->can.state = CAN_STATE_STOPPED;
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);

	can_led_event(net, CAN_LED_EVENT_STOP);

	return 0;
}

static void apalis_tk1_k20_can_error_skb(struct net_device *net, int can_id,
					 int data1)
{
	struct sk_buff *skb;
	struct can_frame *frame;

	skb = alloc_can_err_skb(net, &frame);
	if (skb) {
		frame->can_id |= can_id;
		frame->data[1] = data1;
		netif_rx_ni(skb);
	} else {
		netdev_err(net, "cannot allocate error skb\n");
	}
}

static void apalis_tk1_k20_can_tx_work_handler(struct work_struct *ws)
{
	struct apalis_tk1_k20_priv *priv = container_of(ws,
			struct apalis_tk1_k20_priv, tx_work);
	struct net_device *net = priv->net;
	struct can_frame *frame;

	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	if (priv->tx_skb) {
		if (priv->can.state == CAN_STATE_BUS_OFF) {
			apalis_tk1_k20_can_clean(net);
		} else {
			frame = (struct can_frame *)priv->tx_skb->data;

			if (frame->can_dlc > CAN_FRAME_MAX_LEN)
				frame->can_dlc = CAN_FRAME_MAX_LEN;
			apalis_tk1_k20_can_hw_tx(net, frame, 0);
			priv->tx_len = 1 + frame->can_dlc;
			can_put_echo_skb(priv->tx_skb, net, 0);
			priv->tx_skb = NULL;
		}
	}
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
}

#ifdef CONFIG_PM_SLEEP

static int apalis_tk1_k20_can_suspend(struct device *dev)
{
	struct apalis_tk1_k20_priv *priv = dev_get_drvdata(dev);
	struct apalis_tk1_k20_can_platform_data *pdata = priv->pdata;

	priv->force_quit = 1;

	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	if (pdata->id == 0)
		apalis_tk1_k20_irq_mask(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN0_IRQ);
	if (pdata->id == 1)
		apalis_tk1_k20_irq_mask(priv->apalis_tk1_k20,
					APALIS_TK1_K20_CAN1_IRQ);
	/* Disable interrupts */
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
	/* Note: at this point neither IST nor workqueues are running.
	 * open/stop cannot be called anyway so locking is not needed
	 */
	if (netif_running(priv->net)) {
		netif_device_detach(priv->net);

		priv->after_suspend = AFTER_SUSPEND_UP;
	} else {
		priv->after_suspend = AFTER_SUSPEND_DOWN;
	}

	return 0;
}

static int apalis_tk1_k20_can_resume(struct device *dev)
{
	struct apalis_tk1_k20_priv *priv = dev_get_drvdata(dev);
	struct apalis_tk1_k20_can_platform_data *pdata = priv->pdata;

	if (priv->after_suspend & AFTER_SUSPEND_UP)
		queue_work(priv->wq, &priv->restart_work);
	else
		priv->after_suspend = 0;

	priv->force_quit = 0;
	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	if (pdata->id == 0)
		apalis_tk1_k20_irq_unmask(priv->apalis_tk1_k20,
					  APALIS_TK1_K20_CAN0_IRQ);
	if (pdata->id == 1)
		apalis_tk1_k20_irq_unmask(priv->apalis_tk1_k20,
					  APALIS_TK1_K20_CAN1_IRQ);
	/* Enable interrupts */
	priv->can.state = CAN_STATE_STOPPED;
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
	return 0;
}

static SIMPLE_DEV_PM_OPS(apalis_tk1_k20_can_pm_ops, apalis_tk1_k20_can_suspend,
		apalis_tk1_k20_can_resume);

#endif

static void apalis_tk1_k20_can_restart_work_handler(struct work_struct *ws)
{
	struct apalis_tk1_k20_priv *priv = container_of(ws,
			struct apalis_tk1_k20_priv, restart_work);
	struct net_device *net = priv->net;

	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	if (priv->after_suspend) {
		mdelay(10);
		apalis_tk1_k20_can_hw_reset(net);
		apalis_tk1_k20_can_setup(net, priv);
		if (priv->after_suspend & AFTER_SUSPEND_RESTART) {
			apalis_tk1_k20_can_set_normal_mode(net);
		} else if (priv->after_suspend & AFTER_SUSPEND_UP) {
			netif_device_attach(net);
			apalis_tk1_k20_can_clean(net);
			apalis_tk1_k20_can_set_normal_mode(net);
			netif_wake_queue(net);
		}
		priv->after_suspend = 0;
		priv->force_quit = 0;
	}

	if (priv->restart_tx) {
		priv->restart_tx = 0;
		apalis_tk1_k20_can_clean(net);
		netif_wake_queue(net);
		apalis_tk1_k20_can_error_skb(net, CAN_ERR_RESTARTED, 0);
	}
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
}

static irqreturn_t apalis_tk1_k20_can_ist(int irq, void *dev_id)
{
	struct apalis_tk1_k20_priv *priv = dev_id;
	struct net_device *net = priv->net;
	int max_continuous_read = CAN_MAX_CONTINUOUS_READ;

	mutex_lock(&priv->apalis_tk1_k20_can_lock);
	while (!priv->force_quit && max_continuous_read) {
		enum can_state new_state;
		int ret;
		u32 intf, eflag;
		u8 clear_intf = 0;
		int can_id = 0, data1 = 0;

		apalis_tk1_k20_lock(priv->apalis_tk1_k20);
		ret = apalis_tk1_k20_reg_read(priv->apalis_tk1_k20,
					      APALIS_TK1_K20_CANREG
					      + APALIS_TK1_K20_CAN_DEV_OFFSET(
					      priv->pdata->id), &intf);
		apalis_tk1_k20_unlock(priv->apalis_tk1_k20);

		if (ret) {
			dev_err(&net->dev, "Communication error\n");
			break;
		}

		max_continuous_read--;

		intf &= CANCTRL_INTMASK;
		/* receive */
		if (intf & CANINTF_RX)
			apalis_tk1_k20_can_hw_rx(net, 0);

		/* any error or TX interrupt we need to clear? */
		if (intf & (CANINTF_ERR | CANINTF_TX))
			clear_intf |= intf & (CANINTF_ERR | CANINTF_TX);
		apalis_tk1_k20_lock(priv->apalis_tk1_k20);
		if (clear_intf)
			ret = apalis_tk1_k20_reg_rmw(priv->apalis_tk1_k20,
						     APALIS_TK1_K20_CANREG +
						     APALIS_TK1_K20_CAN_DEV_OFFSET(
						     priv->pdata->id),
						     CANCTRL_INTMASK, 0x00);
		if (ret) {
			apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
			dev_err(&net->dev, "Communication error\n");
			break;
		}
		ret = apalis_tk1_k20_reg_read(priv->apalis_tk1_k20,
					      APALIS_TK1_K20_CANERR +
					      APALIS_TK1_K20_CAN_DEV_OFFSET(
					      priv->pdata->id), &eflag);
		apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
		if (ret) {
			dev_err(&net->dev, "Communication error\n");
			break;
		}
		/* Update can state */
		if (intf & CANINTF_ERR) {
			if (eflag & EFLG_TXBO) {
				new_state = CAN_STATE_BUS_OFF;
				can_id |= CAN_ERR_BUSOFF;
			} else if (eflag & EFLG_TXEP) {
				new_state = CAN_STATE_ERROR_PASSIVE;
				can_id |= CAN_ERR_CRTL;
				data1 |= CAN_ERR_CRTL_TX_PASSIVE;
			} else if (eflag & EFLG_RXEP) {
				new_state = CAN_STATE_ERROR_PASSIVE;
				can_id |= CAN_ERR_CRTL;
				data1 |= CAN_ERR_CRTL_RX_PASSIVE;
			} else if (eflag & EFLG_TXWAR) {
				new_state = CAN_STATE_ERROR_WARNING;
				can_id |= CAN_ERR_CRTL;
				data1 |= CAN_ERR_CRTL_TX_WARNING;
			} else if (eflag & EFLG_RXWAR) {
				new_state = CAN_STATE_ERROR_WARNING;
				can_id |= CAN_ERR_CRTL;
				data1 |= CAN_ERR_CRTL_RX_WARNING;
			} else {
				new_state = CAN_STATE_ERROR_ACTIVE;
			}
		}

		/* Update can state statistics */
		switch (priv->can.state) {
		case CAN_STATE_ERROR_ACTIVE:
			if (new_state >= CAN_STATE_ERROR_WARNING &&
			    new_state <= CAN_STATE_BUS_OFF)
				priv->can.can_stats.error_warning++;
		case CAN_STATE_ERROR_WARNING: /* fallthrough */
			if (new_state >= CAN_STATE_ERROR_PASSIVE &&
			    new_state <= CAN_STATE_BUS_OFF)
				priv->can.can_stats.error_passive++;
			break;
		default:
			break;
		}
		priv->can.state = new_state;

		if (intf & CANINTF_ERR) {
			/* Handle overflow counters */
			if (eflag & EFLG_RXOVR) {
				if (eflag & EFLG_RXOVR) {
					net->stats.rx_over_errors++;
					net->stats.rx_errors++;
				}
				can_id |= CAN_ERR_CRTL;
				data1 |= CAN_ERR_CRTL_RX_OVERFLOW;
			}
			apalis_tk1_k20_can_error_skb(net, can_id, data1);
		}

		if (priv->can.state == CAN_STATE_BUS_OFF &&
		    priv->can.restart_ms == 0) {
			priv->force_quit = 1;
			can_bus_off(net);
			break;
		}

		if (intf == 0)
			break;

		if (intf & CANINTF_TX) {
			net->stats.tx_packets++;
			net->stats.tx_bytes += priv->tx_len - 1;
			can_led_event(net, CAN_LED_EVENT_TX);
			if (priv->tx_len) {
				can_get_echo_skb(net, 0);
				priv->tx_len = 0;
			}
			netif_wake_queue(net);
		}
	}
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
	return IRQ_HANDLED;
}

static int apalis_tk1_k20_can_open(struct net_device *net)
{
	struct apalis_tk1_k20_priv *priv = netdev_priv(net);
	struct apalis_tk1_k20_can_platform_data *pdata = priv->pdata;
	int ret;

	ret = open_candev(net);
	if (ret) {
		dev_err(&net->dev, "unable to initialize CAN\n");
		return ret;
	}

	mutex_lock(&priv->apalis_tk1_k20_can_lock);

	priv->force_quit = 0;
	priv->tx_skb = NULL;
	priv->tx_len = 0;
	apalis_tk1_k20_lock(priv->apalis_tk1_k20);
	if (pdata->id == 0)
		ret = apalis_tk1_k20_irq_request(priv->apalis_tk1_k20,
						 APALIS_TK1_K20_CAN0_IRQ,
						 apalis_tk1_k20_can_ist,
						 DEVICE_NAME, priv);
	if (pdata->id == 1)
		ret = apalis_tk1_k20_irq_request(priv->apalis_tk1_k20,
						 APALIS_TK1_K20_CAN1_IRQ,
						 apalis_tk1_k20_can_ist,
						 DEVICE_NAME, priv);
	apalis_tk1_k20_unlock(priv->apalis_tk1_k20);
	if (ret) {
		dev_err(&net->dev, "failed to acquire IRQ\n");
		close_candev(net);
		goto open_unlock;
	}

	priv->wq = create_freezable_workqueue("apalis_tk1_k20_wq");
	INIT_WORK(&priv->tx_work, apalis_tk1_k20_can_tx_work_handler);
	INIT_WORK(&priv->restart_work, apalis_tk1_k20_can_restart_work_handler);

	ret = apalis_tk1_k20_can_hw_reset(net);
	if (ret) {
		apalis_tk1_k20_can_open_clean(net);
		goto open_unlock;
	}

	ret = apalis_tk1_k20_can_setup(net, priv);
	if (ret) {
		apalis_tk1_k20_can_open_clean(net);
		goto open_unlock;
	}

	ret = apalis_tk1_k20_can_set_normal_mode(net);
	if (ret) {
		apalis_tk1_k20_can_open_clean(net);
		goto open_unlock;
	}

	can_led_event(net, CAN_LED_EVENT_OPEN);

	netif_wake_queue(net);

open_unlock:
	mutex_unlock(&priv->apalis_tk1_k20_can_lock);
	return ret;
}

static const struct net_device_ops apalis_tk1_k20_netdev_ops = {
		.ndo_open = apalis_tk1_k20_can_open,
		.ndo_stop = apalis_tk1_k20_can_stop,
		.ndo_start_xmit = apalis_tk1_k20_can_hard_start_xmit,
};

static int apalis_tk1_k20_can_probe(struct platform_device *pdev)
{
	struct net_device *net;
	struct apalis_tk1_k20_priv *priv;
	struct apalis_tk1_k20_can_platform_data *pdata =
			pdev->dev.platform_data;
	int ret = -ENODEV;

	if (!pdata) {
		pdata = kmalloc(sizeof(struct apalis_tk1_k20_can_platform_data),
				GFP_KERNEL);
		if (pdev->id == -1)
			pdata->id = 0;
		if (pdev->id >= 0 && pdev->id <= K20_CAN_MAX_ID)
			pdata->id = pdev->id;
		else
			goto error_out;
	}

	if (pdata->id > K20_CAN_MAX_ID)
		goto error_out;
	/* Allocate can/net device */
	net = alloc_candev(sizeof(struct apalis_tk1_k20_priv), TX_ECHO_SKB_MAX);
	if (!net) {
		ret = -ENOMEM;
		goto error_out;
	}

	net->netdev_ops = &apalis_tk1_k20_netdev_ops;
	net->flags |= IFF_ECHO;

	priv = netdev_priv(net);
	priv->can.bittiming_const = &apalis_tk1_k20_can_bittiming_const;
	priv->can.do_set_mode = apalis_tk1_k20_can_do_set_mode;
	priv->can.clock.freq = 8000000;
	priv->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES |
			CAN_CTRLMODE_LOOPBACK | CAN_CTRLMODE_LISTENONLY;
	priv->net = net;
	priv->pdata = pdata;
	priv->apalis_tk1_k20 = dev_get_drvdata(pdev->dev.parent);

	mutex_init(&priv->apalis_tk1_k20_can_lock);

	SET_NETDEV_DEV(net, &pdev->dev);

	platform_set_drvdata(pdev, priv);

	ret = register_candev(net);
	if (ret)
		goto error_probe;

	devm_can_led_init(net);

	dev_info(&pdev->dev, "probed %d\n", pdev->id);

	return ret;

error_probe:
	free_candev(net);
error_out:
	return ret;
}

static int apalis_tk1_k20_can_remove(struct platform_device *pdev)
{
	struct apalis_tk1_k20_priv *priv = platform_get_drvdata(pdev);
	struct net_device *net = priv->net;

	unregister_candev(net);
	free_candev(net);

	return 0;
}

static const struct platform_device_id apalis_tk1_k20_can_idtable[] = {
		{.name = "apalis-tk1-k20-can", },
		{ /* sentinel */}
};

MODULE_DEVICE_TABLE(platform, apalis_tk1_k20_can_idtable);

static struct platform_driver apalis_tk1_k20_can_driver = {
		.id_table = apalis_tk1_k20_can_idtable,
		.remove = __exit_p(apalis_tk1_k20_can_remove),
		.driver = {
				.name = DEVICE_NAME,
				.owner = THIS_MODULE,
#ifdef CONFIG_PM_SLEEP
				.pm = &apalis_tk1_k20_can_pm_ops,
#endif
		},
};

module_platform_driver_probe(apalis_tk1_k20_can_driver,
			     &apalis_tk1_k20_can_probe);

MODULE_DESCRIPTION("CAN driver for K20 MCU on Apalis TK1");
MODULE_AUTHOR("Dominik Sliwa <dominik.sliwa@toradex.com>");
MODULE_LICENSE("GPL v2");