aboutsummaryrefslogtreecommitdiff
path: root/sound/firewire/amdtp.c
blob: 31dd1cfc79b3225a31c8873253588705dc62e8be (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
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
/*
 * Audio and Music Data Transmission Protocol (IEC 61883-6) streams
 * with Common Isochronous Packet (IEC 61883-1) headers
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Licensed under the terms of the GNU General Public License, version 2.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/firewire.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/rawmidi.h>
#include "amdtp.h"

#define TICKS_PER_CYCLE		3072
#define CYCLES_PER_SECOND	8000
#define TICKS_PER_SECOND	(TICKS_PER_CYCLE * CYCLES_PER_SECOND)

#define TRANSFER_DELAY_TICKS	0x2e00 /* 479.17 µs */

/* isochronous header parameters */
#define ISO_DATA_LENGTH_SHIFT	16
#define TAG_CIP			1

/* common isochronous packet header parameters */
#define CIP_EOH			(1u << 31)
#define CIP_EOH_MASK		0x80000000
#define CIP_FMT_AM		(0x10 << 24)
#define CIP_FMT_MASK		0x3f000000
#define CIP_SYT_MASK		0x0000ffff
#define CIP_SYT_NO_INFO		0xffff
#define CIP_FDF_MASK		0x00ff0000
#define CIP_FDF_SFC_SHIFT	16

/*
 * Audio and Music transfer protocol specific parameters
 * only "Clock-based rate control mode" is supported
 */
#define AMDTP_FDF_AM824		(0 << (CIP_FDF_SFC_SHIFT + 3))
#define AMDTP_FDF_NO_DATA	0xff
#define AMDTP_DBS_MASK		0x00ff0000
#define AMDTP_DBS_SHIFT		16
#define AMDTP_DBC_MASK		0x000000ff

/* TODO: make these configurable */
#define INTERRUPT_INTERVAL	16
#define QUEUE_LENGTH		48

#define IN_PACKET_HEADER_SIZE	4
#define OUT_PACKET_HEADER_SIZE	0

static void pcm_period_tasklet(unsigned long data);

/**
 * amdtp_stream_init - initialize an AMDTP stream structure
 * @s: the AMDTP stream to initialize
 * @unit: the target of the stream
 * @dir: the direction of stream
 * @flags: the packet transmission method to use
 */
int amdtp_stream_init(struct amdtp_stream *s, struct fw_unit *unit,
		      enum amdtp_stream_direction dir, enum cip_flags flags)
{
	s->unit = fw_unit_get(unit);
	s->direction = dir;
	s->flags = flags;
	s->context = ERR_PTR(-1);
	mutex_init(&s->mutex);
	tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
	s->packet_index = 0;

	init_waitqueue_head(&s->callback_wait);
	s->callbacked = false;
	s->sync_slave = NULL;

	s->rx_blocks_for_midi = UINT_MAX;

	return 0;
}
EXPORT_SYMBOL(amdtp_stream_init);

/**
 * amdtp_stream_destroy - free stream resources
 * @s: the AMDTP stream to destroy
 */
void amdtp_stream_destroy(struct amdtp_stream *s)
{
	WARN_ON(amdtp_stream_running(s));
	mutex_destroy(&s->mutex);
	fw_unit_put(s->unit);
}
EXPORT_SYMBOL(amdtp_stream_destroy);

const unsigned int amdtp_syt_intervals[CIP_SFC_COUNT] = {
	[CIP_SFC_32000]  =  8,
	[CIP_SFC_44100]  =  8,
	[CIP_SFC_48000]  =  8,
	[CIP_SFC_88200]  = 16,
	[CIP_SFC_96000]  = 16,
	[CIP_SFC_176400] = 32,
	[CIP_SFC_192000] = 32,
};
EXPORT_SYMBOL(amdtp_syt_intervals);

const unsigned int amdtp_rate_table[CIP_SFC_COUNT] = {
	[CIP_SFC_32000]  =  32000,
	[CIP_SFC_44100]  =  44100,
	[CIP_SFC_48000]  =  48000,
	[CIP_SFC_88200]  =  88200,
	[CIP_SFC_96000]  =  96000,
	[CIP_SFC_176400] = 176400,
	[CIP_SFC_192000] = 192000,
};
EXPORT_SYMBOL(amdtp_rate_table);

/**
 * amdtp_stream_add_pcm_hw_constraints - add hw constraints for PCM substream
 * @s:		the AMDTP stream, which must be initialized.
 * @runtime:	the PCM substream runtime
 */
int amdtp_stream_add_pcm_hw_constraints(struct amdtp_stream *s,
					struct snd_pcm_runtime *runtime)
{
	int err;

	/* AM824 in IEC 61883-6 can deliver 24bit data */
	err = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
	if (err < 0)
		goto end;

	/*
	 * Currently firewire-lib processes 16 packets in one software
	 * interrupt callback. This equals to 2msec but actually the
	 * interval of the interrupts has a jitter.
	 * Additionally, even if adding a constraint to fit period size to
	 * 2msec, actual calculated frames per period doesn't equal to 2msec,
	 * depending on sampling rate.
	 * Anyway, the interval to call snd_pcm_period_elapsed() cannot 2msec.
	 * Here let us use 5msec for safe period interrupt.
	 */
	err = snd_pcm_hw_constraint_minmax(runtime,
					   SNDRV_PCM_HW_PARAM_PERIOD_TIME,
					   5000, UINT_MAX);
	if (err < 0)
		goto end;

	/* Non-Blocking stream has no more constraints */
	if (!(s->flags & CIP_BLOCKING))
		goto end;

	/*
	 * One AMDTP packet can include some frames. In blocking mode, the
	 * number equals to SYT_INTERVAL. So the number is 8, 16 or 32,
	 * depending on its sampling rate. For accurate period interrupt, it's
	 * preferrable to aligh period/buffer sizes to current SYT_INTERVAL.
	 *
	 * TODO: These constraints can be improved with propper rules.
	 * Currently apply LCM of SYT_INTEVALs.
	 */
	err = snd_pcm_hw_constraint_step(runtime, 0,
					 SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 32);
	if (err < 0)
		goto end;
	err = snd_pcm_hw_constraint_step(runtime, 0,
					 SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 32);
end:
	return err;
}
EXPORT_SYMBOL(amdtp_stream_add_pcm_hw_constraints);

/**
 * amdtp_stream_set_parameters - set stream parameters
 * @s: the AMDTP stream to configure
 * @rate: the sample rate
 * @pcm_channels: the number of PCM samples in each data block, to be encoded
 *                as AM824 multi-bit linear audio
 * @midi_ports: the number of MIDI ports (i.e., MPX-MIDI Data Channels)
 *
 * The parameters must be set before the stream is started, and must not be
 * changed while the stream is running.
 */
void amdtp_stream_set_parameters(struct amdtp_stream *s,
				 unsigned int rate,
				 unsigned int pcm_channels,
				 unsigned int midi_ports)
{
	unsigned int i, sfc, midi_channels;

	midi_channels = DIV_ROUND_UP(midi_ports, 8);

	if (WARN_ON(amdtp_stream_running(s)) |
	    WARN_ON(pcm_channels > AMDTP_MAX_CHANNELS_FOR_PCM) |
	    WARN_ON(midi_channels > AMDTP_MAX_CHANNELS_FOR_MIDI))
		return;

	for (sfc = 0; sfc < ARRAY_SIZE(amdtp_rate_table); ++sfc)
		if (amdtp_rate_table[sfc] == rate)
			goto sfc_found;
	WARN_ON(1);
	return;

sfc_found:
	s->pcm_channels = pcm_channels;
	s->sfc = sfc;
	s->data_block_quadlets = s->pcm_channels + midi_channels;
	s->midi_ports = midi_ports;

	s->syt_interval = amdtp_syt_intervals[sfc];

	/* default buffering in the device */
	s->transfer_delay = TRANSFER_DELAY_TICKS - TICKS_PER_CYCLE;
	if (s->flags & CIP_BLOCKING)
		/* additional buffering needed to adjust for no-data packets */
		s->transfer_delay += TICKS_PER_SECOND * s->syt_interval / rate;

	/* init the position map for PCM and MIDI channels */
	for (i = 0; i < pcm_channels; i++)
		s->pcm_positions[i] = i;
	s->midi_position = s->pcm_channels;
}
EXPORT_SYMBOL(amdtp_stream_set_parameters);

/**
 * amdtp_stream_get_max_payload - get the stream's packet size
 * @s: the AMDTP stream
 *
 * This function must not be called before the stream has been configured
 * with amdtp_stream_set_parameters().
 */
unsigned int amdtp_stream_get_max_payload(struct amdtp_stream *s)
{
	return 8 + s->syt_interval * s->data_block_quadlets * 4;
}
EXPORT_SYMBOL(amdtp_stream_get_max_payload);

static void amdtp_write_s16(struct amdtp_stream *s,
			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames);
static void amdtp_write_s32(struct amdtp_stream *s,
			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames);
static void amdtp_read_s32(struct amdtp_stream *s,
			   struct snd_pcm_substream *pcm,
			   __be32 *buffer, unsigned int frames);

/**
 * amdtp_stream_set_pcm_format - set the PCM format
 * @s: the AMDTP stream to configure
 * @format: the format of the ALSA PCM device
 *
 * The sample format must be set after the other paramters (rate/PCM channels/
 * MIDI) and before the stream is started, and must not be changed while the
 * stream is running.
 */
void amdtp_stream_set_pcm_format(struct amdtp_stream *s,
				 snd_pcm_format_t format)
{
	if (WARN_ON(amdtp_stream_pcm_running(s)))
		return;

	switch (format) {
	default:
		WARN_ON(1);
		/* fall through */
	case SNDRV_PCM_FORMAT_S16:
		if (s->direction == AMDTP_OUT_STREAM) {
			s->transfer_samples = amdtp_write_s16;
			break;
		}
		WARN_ON(1);
		/* fall through */
	case SNDRV_PCM_FORMAT_S32:
		if (s->direction == AMDTP_OUT_STREAM)
			s->transfer_samples = amdtp_write_s32;
		else
			s->transfer_samples = amdtp_read_s32;
		break;
	}
}
EXPORT_SYMBOL(amdtp_stream_set_pcm_format);

/**
 * amdtp_stream_pcm_prepare - prepare PCM device for running
 * @s: the AMDTP stream
 *
 * This function should be called from the PCM device's .prepare callback.
 */
void amdtp_stream_pcm_prepare(struct amdtp_stream *s)
{
	tasklet_kill(&s->period_tasklet);
	s->pcm_buffer_pointer = 0;
	s->pcm_period_pointer = 0;
	s->pointer_flush = true;
}
EXPORT_SYMBOL(amdtp_stream_pcm_prepare);

static unsigned int calculate_data_blocks(struct amdtp_stream *s)
{
	unsigned int phase, data_blocks;

	if (s->flags & CIP_BLOCKING)
		data_blocks = s->syt_interval;
	else if (!cip_sfc_is_base_44100(s->sfc)) {
		/* Sample_rate / 8000 is an integer, and precomputed. */
		data_blocks = s->data_block_state;
	} else {
		phase = s->data_block_state;

		/*
		 * This calculates the number of data blocks per packet so that
		 * 1) the overall rate is correct and exactly synchronized to
		 *    the bus clock, and
		 * 2) packets with a rounded-up number of blocks occur as early
		 *    as possible in the sequence (to prevent underruns of the
		 *    device's buffer).
		 */
		if (s->sfc == CIP_SFC_44100)
			/* 6 6 5 6 5 6 5 ... */
			data_blocks = 5 + ((phase & 1) ^
					   (phase == 0 || phase >= 40));
		else
			/* 12 11 11 11 11 ... or 23 22 22 22 22 ... */
			data_blocks = 11 * (s->sfc >> 1) + (phase == 0);
		if (++phase >= (80 >> (s->sfc >> 1)))
			phase = 0;
		s->data_block_state = phase;
	}

	return data_blocks;
}

static unsigned int calculate_syt(struct amdtp_stream *s,
				  unsigned int cycle)
{
	unsigned int syt_offset, phase, index, syt;

	if (s->last_syt_offset < TICKS_PER_CYCLE) {
		if (!cip_sfc_is_base_44100(s->sfc))
			syt_offset = s->last_syt_offset + s->syt_offset_state;
		else {
		/*
		 * The time, in ticks, of the n'th SYT_INTERVAL sample is:
		 *   n * SYT_INTERVAL * 24576000 / sample_rate
		 * Modulo TICKS_PER_CYCLE, the difference between successive
		 * elements is about 1386.23.  Rounding the results of this
		 * formula to the SYT precision results in a sequence of
		 * differences that begins with:
		 *   1386 1386 1387 1386 1386 1386 1387 1386 1386 1386 1387 ...
		 * This code generates _exactly_ the same sequence.
		 */
			phase = s->syt_offset_state;
			index = phase % 13;
			syt_offset = s->last_syt_offset;
			syt_offset += 1386 + ((index && !(index & 3)) ||
					      phase == 146);
			if (++phase >= 147)
				phase = 0;
			s->syt_offset_state = phase;
		}
	} else
		syt_offset = s->last_syt_offset - TICKS_PER_CYCLE;
	s->last_syt_offset = syt_offset;

	if (syt_offset < TICKS_PER_CYCLE) {
		syt_offset += s->transfer_delay;
		syt = (cycle + syt_offset / TICKS_PER_CYCLE) << 12;
		syt += syt_offset % TICKS_PER_CYCLE;

		return syt & CIP_SYT_MASK;
	} else {
		return CIP_SYT_NO_INFO;
	}
}

static void amdtp_write_s32(struct amdtp_stream *s,
			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	const u32 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			buffer[s->pcm_positions[c]] =
					cpu_to_be32((*src >> 8) | 0x40000000);
			src++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

static void amdtp_write_s16(struct amdtp_stream *s,
			    struct snd_pcm_substream *pcm,
			    __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	const u16 *src;

	channels = s->pcm_channels;
	src = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			buffer[s->pcm_positions[c]] =
					cpu_to_be32((*src << 8) | 0x40000000);
			src++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			src = (void *)runtime->dma_area;
	}
}

static void amdtp_read_s32(struct amdtp_stream *s,
			   struct snd_pcm_substream *pcm,
			   __be32 *buffer, unsigned int frames)
{
	struct snd_pcm_runtime *runtime = pcm->runtime;
	unsigned int channels, remaining_frames, i, c;
	u32 *dst;

	channels = s->pcm_channels;
	dst  = (void *)runtime->dma_area +
			frames_to_bytes(runtime, s->pcm_buffer_pointer);
	remaining_frames = runtime->buffer_size - s->pcm_buffer_pointer;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < channels; ++c) {
			*dst = be32_to_cpu(buffer[s->pcm_positions[c]]) << 8;
			dst++;
		}
		buffer += s->data_block_quadlets;
		if (--remaining_frames == 0)
			dst = (void *)runtime->dma_area;
	}
}

static void amdtp_fill_pcm_silence(struct amdtp_stream *s,
				   __be32 *buffer, unsigned int frames)
{
	unsigned int i, c;

	for (i = 0; i < frames; ++i) {
		for (c = 0; c < s->pcm_channels; ++c)
			buffer[s->pcm_positions[c]] = cpu_to_be32(0x40000000);
		buffer += s->data_block_quadlets;
	}
}

static void amdtp_fill_midi(struct amdtp_stream *s,
			    __be32 *buffer, unsigned int frames)
{
	unsigned int f, port;
	u8 *b;

	for (f = 0; f < frames; f++) {
		buffer[s->midi_position] = 0;
		b = (u8 *)&buffer[s->midi_position];

		port = (s->data_block_counter + f) % 8;
		if ((f >= s->rx_blocks_for_midi) ||
		    (s->midi[port] == NULL) ||
		    (snd_rawmidi_transmit(s->midi[port], b + 1, 1) <= 0))
			b[0] = 0x80;
		else
			b[0] = 0x81;

		buffer += s->data_block_quadlets;
	}
}

static void amdtp_pull_midi(struct amdtp_stream *s,
			    __be32 *buffer, unsigned int frames)
{
	unsigned int f, port;
	int len;
	u8 *b;

	for (f = 0; f < frames; f++) {
		port = (s->data_block_counter + f) % 8;
		b = (u8 *)&buffer[s->midi_position];

		len = b[0] - 0x80;
		if ((1 <= len) &&  (len <= 3) && (s->midi[port]))
			snd_rawmidi_receive(s->midi[port], b + 1, len);

		buffer += s->data_block_quadlets;
	}
}

static void update_pcm_pointers(struct amdtp_stream *s,
				struct snd_pcm_substream *pcm,
				unsigned int frames)
{	unsigned int ptr;

	ptr = s->pcm_buffer_pointer + frames;
	if (ptr >= pcm->runtime->buffer_size)
		ptr -= pcm->runtime->buffer_size;
	ACCESS_ONCE(s->pcm_buffer_pointer) = ptr;

	s->pcm_period_pointer += frames;
	if (s->pcm_period_pointer >= pcm->runtime->period_size) {
		s->pcm_period_pointer -= pcm->runtime->period_size;
		s->pointer_flush = false;
		tasklet_hi_schedule(&s->period_tasklet);
	}
}

static void pcm_period_tasklet(unsigned long data)
{
	struct amdtp_stream *s = (void *)data;
	struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);

	if (pcm)
		snd_pcm_period_elapsed(pcm);
}

static int queue_packet(struct amdtp_stream *s,
			unsigned int header_length,
			unsigned int payload_length, bool skip)
{
	struct fw_iso_packet p = {0};
	int err = 0;

	if (IS_ERR(s->context))
		goto end;

	p.interrupt = IS_ALIGNED(s->packet_index + 1, INTERRUPT_INTERVAL);
	p.tag = TAG_CIP;
	p.header_length = header_length;
	p.payload_length = (!skip) ? payload_length : 0;
	p.skip = skip;
	err = fw_iso_context_queue(s->context, &p, &s->buffer.iso_buffer,
				   s->buffer.packets[s->packet_index].offset);
	if (err < 0) {
		dev_err(&s->unit->device, "queueing error: %d\n", err);
		goto end;
	}

	if (++s->packet_index >= QUEUE_LENGTH)
		s->packet_index = 0;
end:
	return err;
}

static inline int queue_out_packet(struct amdtp_stream *s,
				   unsigned int payload_length, bool skip)
{
	return queue_packet(s, OUT_PACKET_HEADER_SIZE,
			    payload_length, skip);
}

static inline int queue_in_packet(struct amdtp_stream *s)
{
	return queue_packet(s, IN_PACKET_HEADER_SIZE,
			    amdtp_stream_get_max_payload(s), false);
}

static void handle_out_packet(struct amdtp_stream *s, unsigned int syt)
{
	__be32 *buffer;
	unsigned int data_blocks, payload_length;
	struct snd_pcm_substream *pcm;

	if (s->packet_index < 0)
		return;

	/* this module generate empty packet for 'no data' */
	if (!(s->flags & CIP_BLOCKING) || (syt != CIP_SYT_NO_INFO))
		data_blocks = calculate_data_blocks(s);
	else
		data_blocks = 0;

	buffer = s->buffer.packets[s->packet_index].buffer;
	buffer[0] = cpu_to_be32(ACCESS_ONCE(s->source_node_id_field) |
				(s->data_block_quadlets << AMDTP_DBS_SHIFT) |
				s->data_block_counter);
	buffer[1] = cpu_to_be32(CIP_EOH | CIP_FMT_AM | AMDTP_FDF_AM824 |
				(s->sfc << CIP_FDF_SFC_SHIFT) | syt);
	buffer += 2;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm)
		s->transfer_samples(s, pcm, buffer, data_blocks);
	else
		amdtp_fill_pcm_silence(s, buffer, data_blocks);
	if (s->midi_ports)
		amdtp_fill_midi(s, buffer, data_blocks);

	s->data_block_counter = (s->data_block_counter + data_blocks) & 0xff;

	payload_length = 8 + data_blocks * 4 * s->data_block_quadlets;
	if (queue_out_packet(s, payload_length, false) < 0) {
		s->packet_index = -1;
		amdtp_stream_pcm_abort(s);
		return;
	}

	if (pcm)
		update_pcm_pointers(s, pcm, data_blocks);
}

static void handle_in_packet(struct amdtp_stream *s,
			     unsigned int payload_quadlets,
			     __be32 *buffer)
{
	u32 cip_header[2];
	unsigned int data_blocks, data_block_quadlets, data_block_counter,
		     dbc_interval;
	struct snd_pcm_substream *pcm = NULL;
	bool lost;

	cip_header[0] = be32_to_cpu(buffer[0]);
	cip_header[1] = be32_to_cpu(buffer[1]);

	/*
	 * This module supports 'Two-quadlet CIP header with SYT field'.
	 * For convenience, also check FMT field is AM824 or not.
	 */
	if (((cip_header[0] & CIP_EOH_MASK) == CIP_EOH) ||
	    ((cip_header[1] & CIP_EOH_MASK) != CIP_EOH) ||
	    ((cip_header[1] & CIP_FMT_MASK) != CIP_FMT_AM)) {
		dev_info_ratelimited(&s->unit->device,
				"Invalid CIP header for AMDTP: %08X:%08X\n",
				cip_header[0], cip_header[1]);
		goto end;
	}

	/* Calculate data blocks */
	if (payload_quadlets < 3 ||
	    ((cip_header[1] & CIP_FDF_MASK) ==
				(AMDTP_FDF_NO_DATA << CIP_FDF_SFC_SHIFT))) {
		data_blocks = 0;
	} else {
		data_block_quadlets =
			(cip_header[0] & AMDTP_DBS_MASK) >> AMDTP_DBS_SHIFT;
		/* avoid division by zero */
		if (data_block_quadlets == 0) {
			dev_info_ratelimited(&s->unit->device,
				"Detect invalid value in dbs field: %08X\n",
				cip_header[0]);
			goto err;
		}
		if (s->flags & CIP_WRONG_DBS)
			data_block_quadlets = s->data_block_quadlets;

		data_blocks = (payload_quadlets - 2) / data_block_quadlets;
	}

	/* Check data block counter continuity */
	data_block_counter = cip_header[0] & AMDTP_DBC_MASK;
	if (data_blocks == 0 && (s->flags & CIP_EMPTY_HAS_WRONG_DBC) &&
	    s->data_block_counter != UINT_MAX)
		data_block_counter = s->data_block_counter;

	if (((s->flags & CIP_SKIP_DBC_ZERO_CHECK) && data_block_counter == 0) ||
	    (s->data_block_counter == UINT_MAX)) {
		lost = false;
	} else if (!(s->flags & CIP_DBC_IS_END_EVENT)) {
		lost = data_block_counter != s->data_block_counter;
	} else {
		if ((data_blocks > 0) && (s->tx_dbc_interval > 0))
			dbc_interval = s->tx_dbc_interval;
		else
			dbc_interval = data_blocks;

		lost = data_block_counter !=
		       ((s->data_block_counter + dbc_interval) & 0xff);
	}

	if (lost) {
		dev_info(&s->unit->device,
			 "Detect discontinuity of CIP: %02X %02X\n",
			 s->data_block_counter, data_block_counter);
		goto err;
	}

	if (data_blocks > 0) {
		buffer += 2;

		pcm = ACCESS_ONCE(s->pcm);
		if (pcm)
			s->transfer_samples(s, pcm, buffer, data_blocks);

		if (s->midi_ports)
			amdtp_pull_midi(s, buffer, data_blocks);
	}

	if (s->flags & CIP_DBC_IS_END_EVENT)
		s->data_block_counter = data_block_counter;
	else
		s->data_block_counter =
				(data_block_counter + data_blocks) & 0xff;
end:
	if (queue_in_packet(s) < 0)
		goto err;

	if (pcm)
		update_pcm_pointers(s, pcm, data_blocks);

	return;
err:
	s->packet_index = -1;
	amdtp_stream_pcm_abort(s);
}

static void out_stream_callback(struct fw_iso_context *context, u32 cycle,
				size_t header_length, void *header,
				void *private_data)
{
	struct amdtp_stream *s = private_data;
	unsigned int i, syt, packets = header_length / 4;

	/*
	 * Compute the cycle of the last queued packet.
	 * (We need only the four lowest bits for the SYT, so we can ignore
	 * that bits 0-11 must wrap around at 3072.)
	 */
	cycle += QUEUE_LENGTH - packets;

	for (i = 0; i < packets; ++i) {
		syt = calculate_syt(s, ++cycle);
		handle_out_packet(s, syt);
	}
	fw_iso_context_queue_flush(s->context);
}

static void in_stream_callback(struct fw_iso_context *context, u32 cycle,
			       size_t header_length, void *header,
			       void *private_data)
{
	struct amdtp_stream *s = private_data;
	unsigned int p, syt, packets, payload_quadlets;
	__be32 *buffer, *headers = header;

	/* The number of packets in buffer */
	packets = header_length / IN_PACKET_HEADER_SIZE;

	for (p = 0; p < packets; p++) {
		if (s->packet_index < 0)
			break;

		buffer = s->buffer.packets[s->packet_index].buffer;

		/* Process sync slave stream */
		if (s->sync_slave && s->sync_slave->callbacked) {
			syt = be32_to_cpu(buffer[1]) & CIP_SYT_MASK;
			handle_out_packet(s->sync_slave, syt);
		}

		/* The number of quadlets in this packet */
		payload_quadlets =
			(be32_to_cpu(headers[p]) >> ISO_DATA_LENGTH_SHIFT) / 4;
		handle_in_packet(s, payload_quadlets, buffer);
	}

	/* Queueing error or detecting discontinuity */
	if (s->packet_index < 0) {
		/* Abort sync slave. */
		if (s->sync_slave) {
			s->sync_slave->packet_index = -1;
			amdtp_stream_pcm_abort(s->sync_slave);
		}
		return;
	}

	/* when sync to device, flush the packets for slave stream */
	if (s->sync_slave && s->sync_slave->callbacked)
		fw_iso_context_queue_flush(s->sync_slave->context);

	fw_iso_context_queue_flush(s->context);
}

/* processing is done by master callback */
static void slave_stream_callback(struct fw_iso_context *context, u32 cycle,
				  size_t header_length, void *header,
				  void *private_data)
{
	return;
}

/* this is executed one time */
static void amdtp_stream_first_callback(struct fw_iso_context *context,
					u32 cycle, size_t header_length,
					void *header, void *private_data)
{
	struct amdtp_stream *s = private_data;

	/*
	 * For in-stream, first packet has come.
	 * For out-stream, prepared to transmit first packet
	 */
	s->callbacked = true;
	wake_up(&s->callback_wait);

	if (s->direction == AMDTP_IN_STREAM)
		context->callback.sc = in_stream_callback;
	else if ((s->flags & CIP_BLOCKING) && (s->flags & CIP_SYNC_TO_DEVICE))
		context->callback.sc = slave_stream_callback;
	else
		context->callback.sc = out_stream_callback;

	context->callback.sc(context, cycle, header_length, header, s);
}

/**
 * amdtp_stream_start - start transferring packets
 * @s: the AMDTP stream to start
 * @channel: the isochronous channel on the bus
 * @speed: firewire speed code
 *
 * The stream cannot be started until it has been configured with
 * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
 * device can be started.
 */
int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed)
{
	static const struct {
		unsigned int data_block;
		unsigned int syt_offset;
	} initial_state[] = {
		[CIP_SFC_32000]  = {  4, 3072 },
		[CIP_SFC_48000]  = {  6, 1024 },
		[CIP_SFC_96000]  = { 12, 1024 },
		[CIP_SFC_192000] = { 24, 1024 },
		[CIP_SFC_44100]  = {  0,   67 },
		[CIP_SFC_88200]  = {  0,   67 },
		[CIP_SFC_176400] = {  0,   67 },
	};
	unsigned int header_size;
	enum dma_data_direction dir;
	int type, tag, err;

	mutex_lock(&s->mutex);

	if (WARN_ON(amdtp_stream_running(s) ||
		    (s->data_block_quadlets < 1))) {
		err = -EBADFD;
		goto err_unlock;
	}

	if (s->direction == AMDTP_IN_STREAM &&
	    s->flags & CIP_SKIP_INIT_DBC_CHECK)
		s->data_block_counter = UINT_MAX;
	else
		s->data_block_counter = 0;
	s->data_block_state = initial_state[s->sfc].data_block;
	s->syt_offset_state = initial_state[s->sfc].syt_offset;
	s->last_syt_offset = TICKS_PER_CYCLE;

	/* initialize packet buffer */
	if (s->direction == AMDTP_IN_STREAM) {
		dir = DMA_FROM_DEVICE;
		type = FW_ISO_CONTEXT_RECEIVE;
		header_size = IN_PACKET_HEADER_SIZE;
	} else {
		dir = DMA_TO_DEVICE;
		type = FW_ISO_CONTEXT_TRANSMIT;
		header_size = OUT_PACKET_HEADER_SIZE;
	}
	err = iso_packets_buffer_init(&s->buffer, s->unit, QUEUE_LENGTH,
				      amdtp_stream_get_max_payload(s), dir);
	if (err < 0)
		goto err_unlock;

	s->context = fw_iso_context_create(fw_parent_device(s->unit)->card,
					   type, channel, speed, header_size,
					   amdtp_stream_first_callback, s);
	if (IS_ERR(s->context)) {
		err = PTR_ERR(s->context);
		if (err == -EBUSY)
			dev_err(&s->unit->device,
				"no free stream on this controller\n");
		goto err_buffer;
	}

	amdtp_stream_update(s);

	s->packet_index = 0;
	do {
		if (s->direction == AMDTP_IN_STREAM)
			err = queue_in_packet(s);
		else
			err = queue_out_packet(s, 0, true);
		if (err < 0)
			goto err_context;
	} while (s->packet_index > 0);

	/* NOTE: TAG1 matches CIP. This just affects in stream. */
	tag = FW_ISO_CONTEXT_MATCH_TAG1;
	if (s->flags & CIP_EMPTY_WITH_TAG0)
		tag |= FW_ISO_CONTEXT_MATCH_TAG0;

	s->callbacked = false;
	err = fw_iso_context_start(s->context, -1, 0, tag);
	if (err < 0)
		goto err_context;

	mutex_unlock(&s->mutex);

	return 0;

err_context:
	fw_iso_context_destroy(s->context);
	s->context = ERR_PTR(-1);
err_buffer:
	iso_packets_buffer_destroy(&s->buffer, s->unit);
err_unlock:
	mutex_unlock(&s->mutex);

	return err;
}
EXPORT_SYMBOL(amdtp_stream_start);

/**
 * amdtp_stream_pcm_pointer - get the PCM buffer position
 * @s: the AMDTP stream that transports the PCM data
 *
 * Returns the current buffer position, in frames.
 */
unsigned long amdtp_stream_pcm_pointer(struct amdtp_stream *s)
{
	/* this optimization is allowed to be racy */
	if (s->pointer_flush && amdtp_stream_running(s))
		fw_iso_context_flush_completions(s->context);
	else
		s->pointer_flush = true;

	return ACCESS_ONCE(s->pcm_buffer_pointer);
}
EXPORT_SYMBOL(amdtp_stream_pcm_pointer);

/**
 * amdtp_stream_update - update the stream after a bus reset
 * @s: the AMDTP stream
 */
void amdtp_stream_update(struct amdtp_stream *s)
{
	ACCESS_ONCE(s->source_node_id_field) =
		(fw_parent_device(s->unit)->card->node_id & 0x3f) << 24;
}
EXPORT_SYMBOL(amdtp_stream_update);

/**
 * amdtp_stream_stop - stop sending packets
 * @s: the AMDTP stream to stop
 *
 * All PCM and MIDI devices of the stream must be stopped before the stream
 * itself can be stopped.
 */
void amdtp_stream_stop(struct amdtp_stream *s)
{
	mutex_lock(&s->mutex);

	if (!amdtp_stream_running(s)) {
		mutex_unlock(&s->mutex);
		return;
	}

	tasklet_kill(&s->period_tasklet);
	fw_iso_context_stop(s->context);
	fw_iso_context_destroy(s->context);
	s->context = ERR_PTR(-1);
	iso_packets_buffer_destroy(&s->buffer, s->unit);

	s->callbacked = false;

	mutex_unlock(&s->mutex);
}
EXPORT_SYMBOL(amdtp_stream_stop);

/**
 * amdtp_stream_pcm_abort - abort the running PCM device
 * @s: the AMDTP stream about to be stopped
 *
 * If the isochronous stream needs to be stopped asynchronously, call this
 * function first to stop the PCM device.
 */
void amdtp_stream_pcm_abort(struct amdtp_stream *s)
{
	struct snd_pcm_substream *pcm;

	pcm = ACCESS_ONCE(s->pcm);
	if (pcm) {
		snd_pcm_stream_lock_irq(pcm);
		if (snd_pcm_running(pcm))
			snd_pcm_stop(pcm, SNDRV_PCM_STATE_XRUN);
		snd_pcm_stream_unlock_irq(pcm);
	}
}
EXPORT_SYMBOL(amdtp_stream_pcm_abort);