aboutsummaryrefslogtreecommitdiff
path: root/drivers/dma/sirf-dma.c
blob: 6aec3ad814d37f16b69c51f44347d9826e411885 (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
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
/*
 * DMA controller driver for CSR SiRFprimaII
 *
 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
 *
 * Licensed under GPLv2 or later.
 */

#include <linux/module.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/pm_runtime.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_platform.h>
#include <linux/clk.h>
#include <linux/sirfsoc_dma.h>

#include "dmaengine.h"

#define SIRFSOC_DMA_DESCRIPTORS                 16
#define SIRFSOC_DMA_CHANNELS                    16

#define SIRFSOC_DMA_CH_ADDR                     0x00
#define SIRFSOC_DMA_CH_XLEN                     0x04
#define SIRFSOC_DMA_CH_YLEN                     0x08
#define SIRFSOC_DMA_CH_CTRL                     0x0C

#define SIRFSOC_DMA_WIDTH_0                     0x100
#define SIRFSOC_DMA_CH_VALID                    0x140
#define SIRFSOC_DMA_CH_INT                      0x144
#define SIRFSOC_DMA_INT_EN                      0x148
#define SIRFSOC_DMA_INT_EN_CLR			0x14C
#define SIRFSOC_DMA_CH_LOOP_CTRL                0x150
#define SIRFSOC_DMA_CH_LOOP_CTRL_CLR            0x15C

#define SIRFSOC_DMA_MODE_CTRL_BIT               4
#define SIRFSOC_DMA_DIR_CTRL_BIT                5

/* xlen and dma_width register is in 4 bytes boundary */
#define SIRFSOC_DMA_WORD_LEN			4

struct sirfsoc_dma_desc {
	struct dma_async_tx_descriptor	desc;
	struct list_head		node;

	/* SiRFprimaII 2D-DMA parameters */

	int             xlen;           /* DMA xlen */
	int             ylen;           /* DMA ylen */
	int             width;          /* DMA width */
	int             dir;
	bool            cyclic;         /* is loop DMA? */
	u32             addr;		/* DMA buffer address */
};

struct sirfsoc_dma_chan {
	struct dma_chan			chan;
	struct list_head		free;
	struct list_head		prepared;
	struct list_head		queued;
	struct list_head		active;
	struct list_head		completed;
	unsigned long			happened_cyclic;
	unsigned long			completed_cyclic;

	/* Lock for this structure */
	spinlock_t			lock;

	int				mode;
};

struct sirfsoc_dma_regs {
	u32				ctrl[SIRFSOC_DMA_CHANNELS];
	u32				interrupt_en;
};

struct sirfsoc_dma {
	struct dma_device		dma;
	struct tasklet_struct		tasklet;
	struct sirfsoc_dma_chan		channels[SIRFSOC_DMA_CHANNELS];
	void __iomem			*base;
	int				irq;
	struct clk			*clk;
	bool				is_marco;
	struct sirfsoc_dma_regs		regs_save;
};

#define DRV_NAME	"sirfsoc_dma"

static int sirfsoc_dma_runtime_suspend(struct device *dev);

/* Convert struct dma_chan to struct sirfsoc_dma_chan */
static inline
struct sirfsoc_dma_chan *dma_chan_to_sirfsoc_dma_chan(struct dma_chan *c)
{
	return container_of(c, struct sirfsoc_dma_chan, chan);
}

/* Convert struct dma_chan to struct sirfsoc_dma */
static inline struct sirfsoc_dma *dma_chan_to_sirfsoc_dma(struct dma_chan *c)
{
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(c);
	return container_of(schan, struct sirfsoc_dma, channels[c->chan_id]);
}

/* Execute all queued DMA descriptors */
static void sirfsoc_dma_execute(struct sirfsoc_dma_chan *schan)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
	int cid = schan->chan.chan_id;
	struct sirfsoc_dma_desc *sdesc = NULL;

	/*
	 * lock has been held by functions calling this, so we don't hold
	 * lock again
	 */

	sdesc = list_first_entry(&schan->queued, struct sirfsoc_dma_desc,
		node);
	/* Move the first queued descriptor to active list */
	list_move_tail(&sdesc->node, &schan->active);

	/* Start the DMA transfer */
	writel_relaxed(sdesc->width, sdma->base + SIRFSOC_DMA_WIDTH_0 +
		cid * 4);
	writel_relaxed(cid | (schan->mode << SIRFSOC_DMA_MODE_CTRL_BIT) |
		(sdesc->dir << SIRFSOC_DMA_DIR_CTRL_BIT),
		sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_CTRL);
	writel_relaxed(sdesc->xlen, sdma->base + cid * 0x10 +
		SIRFSOC_DMA_CH_XLEN);
	writel_relaxed(sdesc->ylen, sdma->base + cid * 0x10 +
		SIRFSOC_DMA_CH_YLEN);
	writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) |
		(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);

	/*
	 * writel has an implict memory write barrier to make sure data is
	 * flushed into memory before starting DMA
	 */
	writel(sdesc->addr >> 2, sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR);

	if (sdesc->cyclic) {
		writel((1 << cid) | 1 << (cid + 16) |
			readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
		schan->happened_cyclic = schan->completed_cyclic = 0;
	}
}

/* Interrupt handler */
static irqreturn_t sirfsoc_dma_irq(int irq, void *data)
{
	struct sirfsoc_dma *sdma = data;
	struct sirfsoc_dma_chan *schan;
	struct sirfsoc_dma_desc *sdesc = NULL;
	u32 is;
	int ch;

	is = readl(sdma->base + SIRFSOC_DMA_CH_INT);
	while ((ch = fls(is) - 1) >= 0) {
		is &= ~(1 << ch);
		writel_relaxed(1 << ch, sdma->base + SIRFSOC_DMA_CH_INT);
		schan = &sdma->channels[ch];

		spin_lock(&schan->lock);

		sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
			node);
		if (!sdesc->cyclic) {
			/* Execute queued descriptors */
			list_splice_tail_init(&schan->active, &schan->completed);
			if (!list_empty(&schan->queued))
				sirfsoc_dma_execute(schan);
		} else
			schan->happened_cyclic++;

		spin_unlock(&schan->lock);
	}

	/* Schedule tasklet */
	tasklet_schedule(&sdma->tasklet);

	return IRQ_HANDLED;
}

/* process completed descriptors */
static void sirfsoc_dma_process_completed(struct sirfsoc_dma *sdma)
{
	dma_cookie_t last_cookie = 0;
	struct sirfsoc_dma_chan *schan;
	struct sirfsoc_dma_desc *sdesc;
	struct dma_async_tx_descriptor *desc;
	unsigned long flags;
	unsigned long happened_cyclic;
	LIST_HEAD(list);
	int i;

	for (i = 0; i < sdma->dma.chancnt; i++) {
		schan = &sdma->channels[i];

		/* Get all completed descriptors */
		spin_lock_irqsave(&schan->lock, flags);
		if (!list_empty(&schan->completed)) {
			list_splice_tail_init(&schan->completed, &list);
			spin_unlock_irqrestore(&schan->lock, flags);

			/* Execute callbacks and run dependencies */
			list_for_each_entry(sdesc, &list, node) {
				desc = &sdesc->desc;

				if (desc->callback)
					desc->callback(desc->callback_param);

				last_cookie = desc->cookie;
				dma_run_dependencies(desc);
			}

			/* Free descriptors */
			spin_lock_irqsave(&schan->lock, flags);
			list_splice_tail_init(&list, &schan->free);
			schan->chan.completed_cookie = last_cookie;
			spin_unlock_irqrestore(&schan->lock, flags);
		} else {
			/* for cyclic channel, desc is always in active list */
			sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
				node);

			if (!sdesc || (sdesc && !sdesc->cyclic)) {
				/* without active cyclic DMA */
				spin_unlock_irqrestore(&schan->lock, flags);
				continue;
			}

			/* cyclic DMA */
			happened_cyclic = schan->happened_cyclic;
			spin_unlock_irqrestore(&schan->lock, flags);

			desc = &sdesc->desc;
			while (happened_cyclic != schan->completed_cyclic) {
				if (desc->callback)
					desc->callback(desc->callback_param);
				schan->completed_cyclic++;
			}
		}
	}
}

/* DMA Tasklet */
static void sirfsoc_dma_tasklet(unsigned long data)
{
	struct sirfsoc_dma *sdma = (void *)data;

	sirfsoc_dma_process_completed(sdma);
}

/* Submit descriptor to hardware */
static dma_cookie_t sirfsoc_dma_tx_submit(struct dma_async_tx_descriptor *txd)
{
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(txd->chan);
	struct sirfsoc_dma_desc *sdesc;
	unsigned long flags;
	dma_cookie_t cookie;

	sdesc = container_of(txd, struct sirfsoc_dma_desc, desc);

	spin_lock_irqsave(&schan->lock, flags);

	/* Move descriptor to queue */
	list_move_tail(&sdesc->node, &schan->queued);

	cookie = dma_cookie_assign(txd);

	spin_unlock_irqrestore(&schan->lock, flags);

	return cookie;
}

static int sirfsoc_dma_slave_config(struct sirfsoc_dma_chan *schan,
	struct dma_slave_config *config)
{
	unsigned long flags;

	if ((config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) ||
		(config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES))
		return -EINVAL;

	spin_lock_irqsave(&schan->lock, flags);
	schan->mode = (config->src_maxburst == 4 ? 1 : 0);
	spin_unlock_irqrestore(&schan->lock, flags);

	return 0;
}

static int sirfsoc_dma_terminate_all(struct sirfsoc_dma_chan *schan)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
	int cid = schan->chan.chan_id;
	unsigned long flags;

	spin_lock_irqsave(&schan->lock, flags);

	if (!sdma->is_marco) {
		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN) &
			~(1 << cid), sdma->base + SIRFSOC_DMA_INT_EN);
		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
			& ~((1 << cid) | 1 << (cid + 16)),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
	} else {
		writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_INT_EN_CLR);
		writel_relaxed((1 << cid) | 1 << (cid + 16),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL_CLR);
	}

	writel_relaxed(1 << cid, sdma->base + SIRFSOC_DMA_CH_VALID);

	list_splice_tail_init(&schan->active, &schan->free);
	list_splice_tail_init(&schan->queued, &schan->free);

	spin_unlock_irqrestore(&schan->lock, flags);

	return 0;
}

static int sirfsoc_dma_pause_chan(struct sirfsoc_dma_chan *schan)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
	int cid = schan->chan.chan_id;
	unsigned long flags;

	spin_lock_irqsave(&schan->lock, flags);

	if (!sdma->is_marco)
		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
			& ~((1 << cid) | 1 << (cid + 16)),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
	else
		writel_relaxed((1 << cid) | 1 << (cid + 16),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL_CLR);

	spin_unlock_irqrestore(&schan->lock, flags);

	return 0;
}

static int sirfsoc_dma_resume_chan(struct sirfsoc_dma_chan *schan)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(&schan->chan);
	int cid = schan->chan.chan_id;
	unsigned long flags;

	spin_lock_irqsave(&schan->lock, flags);

	if (!sdma->is_marco)
		writel_relaxed(readl_relaxed(sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL)
			| ((1 << cid) | 1 << (cid + 16)),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);
	else
		writel_relaxed((1 << cid) | 1 << (cid + 16),
			sdma->base + SIRFSOC_DMA_CH_LOOP_CTRL);

	spin_unlock_irqrestore(&schan->lock, flags);

	return 0;
}

static int sirfsoc_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
	unsigned long arg)
{
	struct dma_slave_config *config;
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);

	switch (cmd) {
	case DMA_PAUSE:
		return sirfsoc_dma_pause_chan(schan);
	case DMA_RESUME:
		return sirfsoc_dma_resume_chan(schan);
	case DMA_TERMINATE_ALL:
		return sirfsoc_dma_terminate_all(schan);
	case DMA_SLAVE_CONFIG:
		config = (struct dma_slave_config *)arg;
		return sirfsoc_dma_slave_config(schan, config);

	default:
		break;
	}

	return -ENOSYS;
}

/* Alloc channel resources */
static int sirfsoc_dma_alloc_chan_resources(struct dma_chan *chan)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	struct sirfsoc_dma_desc *sdesc;
	unsigned long flags;
	LIST_HEAD(descs);
	int i;

	pm_runtime_get_sync(sdma->dma.dev);

	/* Alloc descriptors for this channel */
	for (i = 0; i < SIRFSOC_DMA_DESCRIPTORS; i++) {
		sdesc = kzalloc(sizeof(*sdesc), GFP_KERNEL);
		if (!sdesc) {
			dev_notice(sdma->dma.dev, "Memory allocation error. "
				"Allocated only %u descriptors\n", i);
			break;
		}

		dma_async_tx_descriptor_init(&sdesc->desc, chan);
		sdesc->desc.flags = DMA_CTRL_ACK;
		sdesc->desc.tx_submit = sirfsoc_dma_tx_submit;

		list_add_tail(&sdesc->node, &descs);
	}

	/* Return error only if no descriptors were allocated */
	if (i == 0)
		return -ENOMEM;

	spin_lock_irqsave(&schan->lock, flags);

	list_splice_tail_init(&descs, &schan->free);
	spin_unlock_irqrestore(&schan->lock, flags);

	return i;
}

/* Free channel resources */
static void sirfsoc_dma_free_chan_resources(struct dma_chan *chan)
{
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
	struct sirfsoc_dma_desc *sdesc, *tmp;
	unsigned long flags;
	LIST_HEAD(descs);

	spin_lock_irqsave(&schan->lock, flags);

	/* Channel must be idle */
	BUG_ON(!list_empty(&schan->prepared));
	BUG_ON(!list_empty(&schan->queued));
	BUG_ON(!list_empty(&schan->active));
	BUG_ON(!list_empty(&schan->completed));

	/* Move data */
	list_splice_tail_init(&schan->free, &descs);

	spin_unlock_irqrestore(&schan->lock, flags);

	/* Free descriptors */
	list_for_each_entry_safe(sdesc, tmp, &descs, node)
		kfree(sdesc);

	pm_runtime_put(sdma->dma.dev);
}

/* Send pending descriptor to hardware */
static void sirfsoc_dma_issue_pending(struct dma_chan *chan)
{
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	unsigned long flags;

	spin_lock_irqsave(&schan->lock, flags);

	if (list_empty(&schan->active) && !list_empty(&schan->queued))
		sirfsoc_dma_execute(schan);

	spin_unlock_irqrestore(&schan->lock, flags);
}

/* Check request completion status */
static enum dma_status
sirfsoc_dma_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
	struct dma_tx_state *txstate)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	unsigned long flags;
	enum dma_status ret;
	struct sirfsoc_dma_desc *sdesc;
	int cid = schan->chan.chan_id;
	unsigned long dma_pos;
	unsigned long dma_request_bytes;
	unsigned long residue;

	spin_lock_irqsave(&schan->lock, flags);

	sdesc = list_first_entry(&schan->active, struct sirfsoc_dma_desc,
			node);
	dma_request_bytes = (sdesc->xlen + 1) * (sdesc->ylen + 1) *
		(sdesc->width * SIRFSOC_DMA_WORD_LEN);

	ret = dma_cookie_status(chan, cookie, txstate);
	dma_pos = readl_relaxed(sdma->base + cid * 0x10 + SIRFSOC_DMA_CH_ADDR)
		<< 2;
	residue = dma_request_bytes - (dma_pos - sdesc->addr);
	dma_set_residue(txstate, residue);

	spin_unlock_irqrestore(&schan->lock, flags);

	return ret;
}

static struct dma_async_tx_descriptor *sirfsoc_dma_prep_interleaved(
	struct dma_chan *chan, struct dma_interleaved_template *xt,
	unsigned long flags)
{
	struct sirfsoc_dma *sdma = dma_chan_to_sirfsoc_dma(chan);
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	struct sirfsoc_dma_desc *sdesc = NULL;
	unsigned long iflags;
	int ret;

	if ((xt->dir != DMA_MEM_TO_DEV) && (xt->dir != DMA_DEV_TO_MEM)) {
		ret = -EINVAL;
		goto err_dir;
	}

	/* Get free descriptor */
	spin_lock_irqsave(&schan->lock, iflags);
	if (!list_empty(&schan->free)) {
		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
			node);
		list_del(&sdesc->node);
	}
	spin_unlock_irqrestore(&schan->lock, iflags);

	if (!sdesc) {
		/* try to free completed descriptors */
		sirfsoc_dma_process_completed(sdma);
		ret = 0;
		goto no_desc;
	}

	/* Place descriptor in prepared list */
	spin_lock_irqsave(&schan->lock, iflags);

	/*
	 * Number of chunks in a frame can only be 1 for prima2
	 * and ylen (number of frame - 1) must be at least 0
	 */
	if ((xt->frame_size == 1) && (xt->numf > 0)) {
		sdesc->cyclic = 0;
		sdesc->xlen = xt->sgl[0].size / SIRFSOC_DMA_WORD_LEN;
		sdesc->width = (xt->sgl[0].size + xt->sgl[0].icg) /
				SIRFSOC_DMA_WORD_LEN;
		sdesc->ylen = xt->numf - 1;
		if (xt->dir == DMA_MEM_TO_DEV) {
			sdesc->addr = xt->src_start;
			sdesc->dir = 1;
		} else {
			sdesc->addr = xt->dst_start;
			sdesc->dir = 0;
		}

		list_add_tail(&sdesc->node, &schan->prepared);
	} else {
		pr_err("sirfsoc DMA Invalid xfer\n");
		ret = -EINVAL;
		goto err_xfer;
	}
	spin_unlock_irqrestore(&schan->lock, iflags);

	return &sdesc->desc;
err_xfer:
	spin_unlock_irqrestore(&schan->lock, iflags);
no_desc:
err_dir:
	return ERR_PTR(ret);
}

static struct dma_async_tx_descriptor *
sirfsoc_dma_prep_cyclic(struct dma_chan *chan, dma_addr_t addr,
	size_t buf_len, size_t period_len,
	enum dma_transfer_direction direction, unsigned long flags, void *context)
{
	struct sirfsoc_dma_chan *schan = dma_chan_to_sirfsoc_dma_chan(chan);
	struct sirfsoc_dma_desc *sdesc = NULL;
	unsigned long iflags;

	/*
	 * we only support cycle transfer with 2 period
	 * If the X-length is set to 0, it would be the loop mode.
	 * The DMA address keeps increasing until reaching the end of a loop
	 * area whose size is defined by (DMA_WIDTH x (Y_LENGTH + 1)). Then
	 * the DMA address goes back to the beginning of this area.
	 * In loop mode, the DMA data region is divided into two parts, BUFA
	 * and BUFB. DMA controller generates interrupts twice in each loop:
	 * when the DMA address reaches the end of BUFA or the end of the
	 * BUFB
	 */
	if (buf_len !=  2 * period_len)
		return ERR_PTR(-EINVAL);

	/* Get free descriptor */
	spin_lock_irqsave(&schan->lock, iflags);
	if (!list_empty(&schan->free)) {
		sdesc = list_first_entry(&schan->free, struct sirfsoc_dma_desc,
			node);
		list_del(&sdesc->node);
	}
	spin_unlock_irqrestore(&schan->lock, iflags);

	if (!sdesc)
		return NULL;

	/* Place descriptor in prepared list */
	spin_lock_irqsave(&schan->lock, iflags);
	sdesc->addr = addr;
	sdesc->cyclic = 1;
	sdesc->xlen = 0;
	sdesc->ylen = buf_len / SIRFSOC_DMA_WORD_LEN - 1;
	sdesc->width = 1;
	list_add_tail(&sdesc->node, &schan->prepared);
	spin_unlock_irqrestore(&schan->lock, iflags);

	return &sdesc->desc;
}

/*
 * The DMA controller consists of 16 independent DMA channels.
 * Each channel is allocated to a different function
 */
bool sirfsoc_dma_filter_id(struct dma_chan *chan, void *chan_id)
{
	unsigned int ch_nr = (unsigned int) chan_id;

	if (ch_nr == chan->chan_id +
		chan->device->dev_id * SIRFSOC_DMA_CHANNELS)
		return true;

	return false;
}
EXPORT_SYMBOL(sirfsoc_dma_filter_id);

static int sirfsoc_dma_probe(struct platform_device *op)
{
	struct device_node *dn = op->dev.of_node;
	struct device *dev = &op->dev;
	struct dma_device *dma;
	struct sirfsoc_dma *sdma;
	struct sirfsoc_dma_chan *schan;
	struct resource res;
	ulong regs_start, regs_size;
	u32 id;
	int ret, i;

	sdma = devm_kzalloc(dev, sizeof(*sdma), GFP_KERNEL);
	if (!sdma) {
		dev_err(dev, "Memory exhausted!\n");
		return -ENOMEM;
	}

	if (of_device_is_compatible(dn, "sirf,marco-dmac"))
		sdma->is_marco = true;

	if (of_property_read_u32(dn, "cell-index", &id)) {
		dev_err(dev, "Fail to get DMAC index\n");
		return -ENODEV;
	}

	sdma->irq = irq_of_parse_and_map(dn, 0);
	if (sdma->irq == NO_IRQ) {
		dev_err(dev, "Error mapping IRQ!\n");
		return -EINVAL;
	}

	sdma->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(sdma->clk)) {
		dev_err(dev, "failed to get a clock.\n");
		return PTR_ERR(sdma->clk);
	}

	ret = of_address_to_resource(dn, 0, &res);
	if (ret) {
		dev_err(dev, "Error parsing memory region!\n");
		goto irq_dispose;
	}

	regs_start = res.start;
	regs_size = resource_size(&res);

	sdma->base = devm_ioremap(dev, regs_start, regs_size);
	if (!sdma->base) {
		dev_err(dev, "Error mapping memory region!\n");
		ret = -ENOMEM;
		goto irq_dispose;
	}

	ret = request_irq(sdma->irq, &sirfsoc_dma_irq, 0, DRV_NAME, sdma);
	if (ret) {
		dev_err(dev, "Error requesting IRQ!\n");
		ret = -EINVAL;
		goto irq_dispose;
	}

	dma = &sdma->dma;
	dma->dev = dev;
	dma->chancnt = SIRFSOC_DMA_CHANNELS;

	dma->device_alloc_chan_resources = sirfsoc_dma_alloc_chan_resources;
	dma->device_free_chan_resources = sirfsoc_dma_free_chan_resources;
	dma->device_issue_pending = sirfsoc_dma_issue_pending;
	dma->device_control = sirfsoc_dma_control;
	dma->device_tx_status = sirfsoc_dma_tx_status;
	dma->device_prep_interleaved_dma = sirfsoc_dma_prep_interleaved;
	dma->device_prep_dma_cyclic = sirfsoc_dma_prep_cyclic;

	INIT_LIST_HEAD(&dma->channels);
	dma_cap_set(DMA_SLAVE, dma->cap_mask);
	dma_cap_set(DMA_CYCLIC, dma->cap_mask);
	dma_cap_set(DMA_INTERLEAVE, dma->cap_mask);
	dma_cap_set(DMA_PRIVATE, dma->cap_mask);

	for (i = 0; i < dma->chancnt; i++) {
		schan = &sdma->channels[i];

		schan->chan.device = dma;
		dma_cookie_init(&schan->chan);

		INIT_LIST_HEAD(&schan->free);
		INIT_LIST_HEAD(&schan->prepared);
		INIT_LIST_HEAD(&schan->queued);
		INIT_LIST_HEAD(&schan->active);
		INIT_LIST_HEAD(&schan->completed);

		spin_lock_init(&schan->lock);
		list_add_tail(&schan->chan.device_node, &dma->channels);
	}

	tasklet_init(&sdma->tasklet, sirfsoc_dma_tasklet, (unsigned long)sdma);

	/* Register DMA engine */
	dev_set_drvdata(dev, sdma);

	ret = dma_async_device_register(dma);
	if (ret)
		goto free_irq;

	pm_runtime_enable(&op->dev);
	dev_info(dev, "initialized SIRFSOC DMAC driver\n");

	return 0;

free_irq:
	free_irq(sdma->irq, sdma);
irq_dispose:
	irq_dispose_mapping(sdma->irq);
	return ret;
}

static int sirfsoc_dma_remove(struct platform_device *op)
{
	struct device *dev = &op->dev;
	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);

	dma_async_device_unregister(&sdma->dma);
	free_irq(sdma->irq, sdma);
	irq_dispose_mapping(sdma->irq);
	pm_runtime_disable(&op->dev);
	if (!pm_runtime_status_suspended(&op->dev))
		sirfsoc_dma_runtime_suspend(&op->dev);

	return 0;
}

static int sirfsoc_dma_runtime_suspend(struct device *dev)
{
	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);

	clk_disable_unprepare(sdma->clk);
	return 0;
}

static int sirfsoc_dma_runtime_resume(struct device *dev)
{
	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
	int ret;

	ret = clk_prepare_enable(sdma->clk);
	if (ret < 0) {
		dev_err(dev, "clk_enable failed: %d\n", ret);
		return ret;
	}
	return 0;
}

static int sirfsoc_dma_pm_suspend(struct device *dev)
{
	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
	struct sirfsoc_dma_regs *save = &sdma->regs_save;
	struct sirfsoc_dma_desc *sdesc;
	struct sirfsoc_dma_chan *schan;
	int ch;
	int ret;

	/*
	 * if we were runtime-suspended before, resume to enable clock
	 * before accessing register
	 */
	if (pm_runtime_status_suspended(dev)) {
		ret = sirfsoc_dma_runtime_resume(dev);
		if (ret < 0)
			return ret;
	}

	/*
	 * DMA controller will lose all registers while suspending
	 * so we need to save registers for active channels
	 */
	for (ch = 0; ch < SIRFSOC_DMA_CHANNELS; ch++) {
		schan = &sdma->channels[ch];
		if (list_empty(&schan->active))
			continue;
		sdesc = list_first_entry(&schan->active,
			struct sirfsoc_dma_desc,
			node);
		save->ctrl[ch] = readl_relaxed(sdma->base +
			ch * 0x10 + SIRFSOC_DMA_CH_CTRL);
	}
	save->interrupt_en = readl_relaxed(sdma->base + SIRFSOC_DMA_INT_EN);

	/* Disable clock */
	sirfsoc_dma_runtime_suspend(dev);

	return 0;
}

static int sirfsoc_dma_pm_resume(struct device *dev)
{
	struct sirfsoc_dma *sdma = dev_get_drvdata(dev);
	struct sirfsoc_dma_regs *save = &sdma->regs_save;
	struct sirfsoc_dma_desc *sdesc;
	struct sirfsoc_dma_chan *schan;
	int ch;
	int ret;

	/* Enable clock before accessing register */
	ret = sirfsoc_dma_runtime_resume(dev);
	if (ret < 0)
		return ret;

	writel_relaxed(save->interrupt_en, sdma->base + SIRFSOC_DMA_INT_EN);
	for (ch = 0; ch < SIRFSOC_DMA_CHANNELS; ch++) {
		schan = &sdma->channels[ch];
		if (list_empty(&schan->active))
			continue;
		sdesc = list_first_entry(&schan->active,
			struct sirfsoc_dma_desc,
			node);
		writel_relaxed(sdesc->width,
			sdma->base + SIRFSOC_DMA_WIDTH_0 + ch * 4);
		writel_relaxed(sdesc->xlen,
			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_XLEN);
		writel_relaxed(sdesc->ylen,
			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_YLEN);
		writel_relaxed(save->ctrl[ch],
			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_CTRL);
		writel_relaxed(sdesc->addr >> 2,
			sdma->base + ch * 0x10 + SIRFSOC_DMA_CH_ADDR);
	}

	/* if we were runtime-suspended before, suspend again */
	if (pm_runtime_status_suspended(dev))
		sirfsoc_dma_runtime_suspend(dev);

	return 0;
}

static const struct dev_pm_ops sirfsoc_dma_pm_ops = {
	SET_RUNTIME_PM_OPS(sirfsoc_dma_runtime_suspend, sirfsoc_dma_runtime_resume, NULL)
	SET_SYSTEM_SLEEP_PM_OPS(sirfsoc_dma_pm_suspend, sirfsoc_dma_pm_resume)
};

static struct of_device_id sirfsoc_dma_match[] = {
	{ .compatible = "sirf,prima2-dmac", },
	{ .compatible = "sirf,marco-dmac", },
	{},
};

static struct platform_driver sirfsoc_dma_driver = {
	.probe		= sirfsoc_dma_probe,
	.remove		= sirfsoc_dma_remove,
	.driver = {
		.name = DRV_NAME,
		.owner = THIS_MODULE,
		.pm = &sirfsoc_dma_pm_ops,
		.of_match_table	= sirfsoc_dma_match,
	},
};

static __init int sirfsoc_dma_init(void)
{
	return platform_driver_register(&sirfsoc_dma_driver);
}

static void __exit sirfsoc_dma_exit(void)
{
	platform_driver_unregister(&sirfsoc_dma_driver);
}

subsys_initcall(sirfsoc_dma_init);
module_exit(sirfsoc_dma_exit);

MODULE_AUTHOR("Rongjun Ying <rongjun.ying@csr.com>, "
	"Barry Song <baohua.song@csr.com>");
MODULE_DESCRIPTION("SIRFSOC DMA control driver");
MODULE_LICENSE("GPL v2");