summaryrefslogtreecommitdiffstats
path: root/sound/isa/sb/emu8000_pcm.c
blob: f8d90a1e989b0925797d1dfc24849840b36b39e5 (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
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * pcm emulation on emu8000 wavetable
 *
 *  Copyright (C) 2002 Takashi Iwai <tiwai@suse.de>
 */

#include "emu8000_local.h"

#include <linux/sched/signal.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <sound/initval.h>
#include <sound/pcm.h>

/*
 * define the following if you want to use this pcm with non-interleaved mode
 */
/* #define USE_NONINTERLEAVE */

/* NOTE: for using the non-interleaved mode with alsa-lib, you have to set
 * mmap_emulation flag to 1 in your .asoundrc, such like
 *
 *	pcm.emu8k {
 *		type plug
 *		slave.pcm {
 *			type hw
 *			card 0
 *			device 1
 *			mmap_emulation 1
 *		}
 *	}
 *
 * besides, for the time being, the non-interleaved mode doesn't work well on
 * alsa-lib...
 */


struct snd_emu8k_pcm {
	struct snd_emu8000 *emu;
	struct snd_pcm_substream *substream;

	unsigned int allocated_bytes;
	struct snd_util_memblk *block;
	unsigned int offset;
	unsigned int buf_size;
	unsigned int period_size;
	unsigned int loop_start[2];
	unsigned int pitch;
	int panning[2];
	int last_ptr;
	int period_pos;
	int voices;
	unsigned int dram_opened: 1;
	unsigned int running: 1;
	unsigned int timer_running: 1;
	struct timer_list timer;
	spinlock_t timer_lock;
};

#define LOOP_BLANK_SIZE		8


/*
 * open up channels for the simultaneous data transfer and playback
 */
static int
emu8k_open_dram_for_pcm(struct snd_emu8000 *emu, int channels)
{
	int i;

	/* reserve up to 2 voices for playback */
	snd_emux_lock_voice(emu->emu, 0);
	if (channels > 1)
		snd_emux_lock_voice(emu->emu, 1);

	/* reserve 28 voices for loading */
	for (i = channels + 1; i < EMU8000_DRAM_VOICES; i++) {
		unsigned int mode = EMU8000_RAM_WRITE;
		snd_emux_lock_voice(emu->emu, i);
#ifndef USE_NONINTERLEAVE
		if (channels > 1 && (i & 1) != 0)
			mode |= EMU8000_RAM_RIGHT;
#endif
		snd_emu8000_dma_chan(emu, i, mode);
	}

	/* assign voice 31 and 32 to ROM */
	EMU8000_VTFT_WRITE(emu, 30, 0);
	EMU8000_PSST_WRITE(emu, 30, 0x1d8);
	EMU8000_CSL_WRITE(emu, 30, 0x1e0);
	EMU8000_CCCA_WRITE(emu, 30, 0x1d8);
	EMU8000_VTFT_WRITE(emu, 31, 0);
	EMU8000_PSST_WRITE(emu, 31, 0x1d8);
	EMU8000_CSL_WRITE(emu, 31, 0x1e0);
	EMU8000_CCCA_WRITE(emu, 31, 0x1d8);

	return 0;
}

/*
 */
static void
snd_emu8000_write_wait(struct snd_emu8000 *emu, int can_schedule)
{
	while ((EMU8000_SMALW_READ(emu) & 0x80000000) != 0) {
		if (can_schedule) {
			schedule_timeout_interruptible(1);
			if (signal_pending(current))
				break;
		}
	}
}

/*
 * close all channels
 */
static void
emu8k_close_dram(struct snd_emu8000 *emu)
{
	int i;

	for (i = 0; i < 2; i++)
		snd_emux_unlock_voice(emu->emu, i);
	for (; i < EMU8000_DRAM_VOICES; i++) {
		snd_emu8000_dma_chan(emu, i, EMU8000_RAM_CLOSE);
		snd_emux_unlock_voice(emu->emu, i);
	}
}

/*
 * convert Hz to AWE32 rate offset (see emux/soundfont.c)
 */

#define OFFSET_SAMPLERATE	1011119		/* base = 44100 */
#define SAMPLERATE_RATIO	4096

static int calc_rate_offset(int hz)
{
	return snd_sf_linear_to_log(hz, OFFSET_SAMPLERATE, SAMPLERATE_RATIO);
}


/*
 */

static const struct snd_pcm_hardware emu8k_pcm_hw = {
#ifdef USE_NONINTERLEAVE
	.info =			SNDRV_PCM_INFO_NONINTERLEAVED,
#else
	.info =			SNDRV_PCM_INFO_INTERLEAVED,
#endif
	.formats =		SNDRV_PCM_FMTBIT_S16_LE,
	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
	.rate_min =		4000,
	.rate_max =		48000,
	.channels_min =		1,
	.channels_max =		2,
	.buffer_bytes_max =	(128*1024),
	.period_bytes_min =	1024,
	.period_bytes_max =	(128*1024),
	.periods_min =		2,
	.periods_max =		1024,
	.fifo_size =		0,

};

/*
 * get the current position at the given channel from CCCA register
 */
static inline int emu8k_get_curpos(struct snd_emu8k_pcm *rec, int ch)
{
	int val = EMU8000_CCCA_READ(rec->emu, ch) & 0xfffffff;
	val -= rec->loop_start[ch] - 1;
	return val;
}


/*
 * timer interrupt handler
 * check the current position and update the period if necessary.
 */
static void emu8k_pcm_timer_func(struct timer_list *t)
{
	struct snd_emu8k_pcm *rec = from_timer(rec, t, timer);
	int ptr, delta;

	spin_lock(&rec->timer_lock);
	/* update the current pointer */
	ptr = emu8k_get_curpos(rec, 0);
	if (ptr < rec->last_ptr)
		delta = ptr + rec->buf_size - rec->last_ptr;
	else
		delta = ptr - rec->last_ptr;
	rec->period_pos += delta;
	rec->last_ptr = ptr;

	/* reprogram timer */
	mod_timer(&rec->timer, jiffies + 1);

	/* update period */
	if (rec->period_pos >= (int)rec->period_size) {
		rec->period_pos %= rec->period_size;
		spin_unlock(&rec->timer_lock);
		snd_pcm_period_elapsed(rec->substream);
		return;
	}
	spin_unlock(&rec->timer_lock);
}


/*
 * open pcm
 * creating an instance here
 */
static int emu8k_pcm_open(struct snd_pcm_substream *subs)
{
	struct snd_emu8000 *emu = snd_pcm_substream_chip(subs);
	struct snd_emu8k_pcm *rec;
	struct snd_pcm_runtime *runtime = subs->runtime;

	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
	if (! rec)
		return -ENOMEM;

	rec->emu = emu;
	rec->substream = subs;
	runtime->private_data = rec;

	spin_lock_init(&rec->timer_lock);
	timer_setup(&rec->timer, emu8k_pcm_timer_func, 0);

	runtime->hw = emu8k_pcm_hw;
	runtime->hw.buffer_bytes_max = emu->mem_size - LOOP_BLANK_SIZE * 3;
	runtime->hw.period_bytes_max = runtime->hw.buffer_bytes_max / 2;

	/* use timer to update periods.. (specified in msec) */
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
				     (1000000 + HZ - 1) / HZ, UINT_MAX);

	return 0;
}

static int emu8k_pcm_close(struct snd_pcm_substream *subs)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	kfree(rec);
	subs->runtime->private_data = NULL;
	return 0;
}

/*
 * calculate pitch target
 */
static int calc_pitch_target(int pitch)
{
	int ptarget = 1 << (pitch >> 12);
	if (pitch & 0x800) ptarget += (ptarget * 0x102e) / 0x2710;
	if (pitch & 0x400) ptarget += (ptarget * 0x764) / 0x2710;
	if (pitch & 0x200) ptarget += (ptarget * 0x389) / 0x2710;
	ptarget += (ptarget >> 1);
	if (ptarget > 0xffff) ptarget = 0xffff;
	return ptarget;
}

/*
 * set up the voice
 */
static void setup_voice(struct snd_emu8k_pcm *rec, int ch)
{
	struct snd_emu8000 *hw = rec->emu;
	unsigned int temp;

	/* channel to be silent and idle */
	EMU8000_DCYSUSV_WRITE(hw, ch, 0x0080);
	EMU8000_VTFT_WRITE(hw, ch, 0x0000FFFF);
	EMU8000_CVCF_WRITE(hw, ch, 0x0000FFFF);
	EMU8000_PTRX_WRITE(hw, ch, 0);
	EMU8000_CPF_WRITE(hw, ch, 0);

	/* pitch offset */
	EMU8000_IP_WRITE(hw, ch, rec->pitch);
	/* set envelope parameters */
	EMU8000_ENVVAL_WRITE(hw, ch, 0x8000);
	EMU8000_ATKHLD_WRITE(hw, ch, 0x7f7f);
	EMU8000_DCYSUS_WRITE(hw, ch, 0x7f7f);
	EMU8000_ENVVOL_WRITE(hw, ch, 0x8000);
	EMU8000_ATKHLDV_WRITE(hw, ch, 0x7f7f);
	/* decay/sustain parameter for volume envelope is used
	   for triggerg the voice */
	/* modulation envelope heights */
	EMU8000_PEFE_WRITE(hw, ch, 0x0);
	/* lfo1/2 delay */
	EMU8000_LFO1VAL_WRITE(hw, ch, 0x8000);
	EMU8000_LFO2VAL_WRITE(hw, ch, 0x8000);
	/* lfo1 pitch & cutoff shift */
	EMU8000_FMMOD_WRITE(hw, ch, 0);
	/* lfo1 volume & freq */
	EMU8000_TREMFRQ_WRITE(hw, ch, 0);
	/* lfo2 pitch & freq */
	EMU8000_FM2FRQ2_WRITE(hw, ch, 0);
	/* pan & loop start */
	temp = rec->panning[ch];
	temp = (temp <<24) | ((unsigned int)rec->loop_start[ch] - 1);
	EMU8000_PSST_WRITE(hw, ch, temp);
	/* chorus & loop end (chorus 8bit, MSB) */
	temp = 0; // chorus
	temp = (temp << 24) | ((unsigned int)rec->loop_start[ch] + rec->buf_size - 1);
	EMU8000_CSL_WRITE(hw, ch, temp);
	/* Q & current address (Q 4bit value, MSB) */
	temp = 0; // filterQ
	temp = (temp << 28) | ((unsigned int)rec->loop_start[ch] - 1);
	EMU8000_CCCA_WRITE(hw, ch, temp);
	/* clear unknown registers */
	EMU8000_00A0_WRITE(hw, ch, 0);
	EMU8000_0080_WRITE(hw, ch, 0);
}

/*
 * trigger the voice
 */
static void start_voice(struct snd_emu8k_pcm *rec, int ch)
{
	unsigned long flags;
	struct snd_emu8000 *hw = rec->emu;
	unsigned int temp, aux;
	int pt = calc_pitch_target(rec->pitch);

	/* cutoff and volume */
	EMU8000_IFATN_WRITE(hw, ch, 0xff00);
	EMU8000_VTFT_WRITE(hw, ch, 0xffff);
	EMU8000_CVCF_WRITE(hw, ch, 0xffff);
	/* trigger envelope */
	EMU8000_DCYSUSV_WRITE(hw, ch, 0x7f7f);
	/* set reverb and pitch target */
	temp = 0; // reverb
	if (rec->panning[ch] == 0)
		aux = 0xff;
	else
		aux = (-rec->panning[ch]) & 0xff;
	temp = (temp << 8) | (pt << 16) | aux;
	EMU8000_PTRX_WRITE(hw, ch, temp);
	EMU8000_CPF_WRITE(hw, ch, pt << 16);

	/* start timer */
	spin_lock_irqsave(&rec->timer_lock, flags);
	if (! rec->timer_running) {
		mod_timer(&rec->timer, jiffies + 1);
		rec->timer_running = 1;
	}
	spin_unlock_irqrestore(&rec->timer_lock, flags);
}

/*
 * stop the voice immediately
 */
static void stop_voice(struct snd_emu8k_pcm *rec, int ch)
{
	unsigned long flags;
	struct snd_emu8000 *hw = rec->emu;

	EMU8000_DCYSUSV_WRITE(hw, ch, 0x807F);

	/* stop timer */
	spin_lock_irqsave(&rec->timer_lock, flags);
	if (rec->timer_running) {
		del_timer(&rec->timer);
		rec->timer_running = 0;
	}
	spin_unlock_irqrestore(&rec->timer_lock, flags);
}

static int emu8k_pcm_trigger(struct snd_pcm_substream *subs, int cmd)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	int ch;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		for (ch = 0; ch < rec->voices; ch++)
			start_voice(rec, ch);
		rec->running = 1;
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		rec->running = 0;
		for (ch = 0; ch < rec->voices; ch++)
			stop_voice(rec, ch);
		break;
	default:
		return -EINVAL;
	}
	return 0;
}


/*
 * copy / silence ops
 */

/*
 * this macro should be inserted in the copy/silence loops
 * to reduce the latency.  without this, the system will hang up
 * during the whole loop.
 */
#define CHECK_SCHEDULER() \
do { \
	cond_resched();\
	if (signal_pending(current))\
		return -EAGAIN;\
} while (0)

enum {
	COPY_USER, COPY_KERNEL, FILL_SILENCE,
};

#define GET_VAL(sval, buf, mode)					\
	do {								\
		switch (mode) {						\
		case FILL_SILENCE:					\
			sval = 0;					\
			break;						\
		case COPY_KERNEL:					\
			sval = *buf++;					\
			break;						\
		default:						\
			if (get_user(sval, (unsigned short __user *)buf)) \
				return -EFAULT;				\
			buf++;						\
			break;						\
		}							\
	} while (0)

#ifdef USE_NONINTERLEAVE

#define LOOP_WRITE(rec, offset, _buf, count, mode)		\
	do {							\
		struct snd_emu8000 *emu = (rec)->emu;		\
		unsigned short *buf = (__force unsigned short *)(_buf); \
		snd_emu8000_write_wait(emu, 1);			\
		EMU8000_SMALW_WRITE(emu, offset);		\
		while (count > 0) {				\
			unsigned short sval;			\
			CHECK_SCHEDULER();			\
			GET_VAL(sval, buf, mode);		\
			EMU8000_SMLD_WRITE(emu, sval);		\
			count--;				\
		}						\
	} while (0)

/* copy one channel block */
static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
			  int voice, unsigned long pos,
			  void __user *src, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to word unit */
	pos = (pos << 1) + rec->loop_start[voice];
	count <<= 1;
	LOOP_WRITE(rec, pos, src, count, COPY_USER);
	return 0;
}

static int emu8k_pcm_copy_kernel(struct snd_pcm_substream *subs,
				 int voice, unsigned long pos,
				 void *src, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to word unit */
	pos = (pos << 1) + rec->loop_start[voice];
	count <<= 1;
	LOOP_WRITE(rec, pos, src, count, COPY_KERNEL);
	return 0;
}

/* make a channel block silence */
static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
			     int voice, unsigned long pos, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to word unit */
	pos = (pos << 1) + rec->loop_start[voice];
	count <<= 1;
	LOOP_WRITE(rec, pos, NULL, count, FILL_SILENCE);
	return 0;
}

#else /* interleave */

#define LOOP_WRITE(rec, pos, _buf, count, mode)				\
	do {								\
		struct snd_emu8000 *emu = rec->emu;			\
		unsigned short *buf = (__force unsigned short *)(_buf);	\
		snd_emu8000_write_wait(emu, 1);				\
		EMU8000_SMALW_WRITE(emu, pos + rec->loop_start[0]);	\
		if (rec->voices > 1)					\
			EMU8000_SMARW_WRITE(emu, pos + rec->loop_start[1]); \
		while (count > 0) {					\
			unsigned short sval;				\
			CHECK_SCHEDULER();				\
			GET_VAL(sval, buf, mode);			\
			EMU8000_SMLD_WRITE(emu, sval);			\
			if (rec->voices > 1) {				\
				CHECK_SCHEDULER();			\
				GET_VAL(sval, buf, mode);		\
				EMU8000_SMRD_WRITE(emu, sval);		\
			}						\
			count--;					\
		}							\
	} while (0)


/*
 * copy the interleaved data can be done easily by using
 * DMA "left" and "right" channels on emu8k engine.
 */
static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
			  int voice, unsigned long pos,
			  void __user *src, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to frames */
	pos = bytes_to_frames(subs->runtime, pos);
	count = bytes_to_frames(subs->runtime, count);
	LOOP_WRITE(rec, pos, src, count, COPY_USER);
	return 0;
}

static int emu8k_pcm_copy_kernel(struct snd_pcm_substream *subs,
				 int voice, unsigned long pos,
				 void *src, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to frames */
	pos = bytes_to_frames(subs->runtime, pos);
	count = bytes_to_frames(subs->runtime, count);
	LOOP_WRITE(rec, pos, src, count, COPY_KERNEL);
	return 0;
}

static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
			     int voice, unsigned long pos, unsigned long count)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	/* convert to frames */
	pos = bytes_to_frames(subs->runtime, pos);
	count = bytes_to_frames(subs->runtime, count);
	LOOP_WRITE(rec, pos, NULL, count, FILL_SILENCE);
	return 0;
}
#endif


/*
 * allocate a memory block
 */
static int emu8k_pcm_hw_params(struct snd_pcm_substream *subs,
			       struct snd_pcm_hw_params *hw_params)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	if (rec->block) {
		/* reallocation - release the old block */
		snd_util_mem_free(rec->emu->memhdr, rec->block);
		rec->block = NULL;
	}

	rec->allocated_bytes = params_buffer_bytes(hw_params) + LOOP_BLANK_SIZE * 4;
	rec->block = snd_util_mem_alloc(rec->emu->memhdr, rec->allocated_bytes);
	if (! rec->block)
		return -ENOMEM;
	rec->offset = EMU8000_DRAM_OFFSET + (rec->block->offset >> 1); /* in word */
	/* at least dma_bytes must be set for non-interleaved mode */
	subs->dma_buffer.bytes = params_buffer_bytes(hw_params);

	return 0;
}

/*
 * free the memory block
 */
static int emu8k_pcm_hw_free(struct snd_pcm_substream *subs)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	if (rec->block) {
		int ch;
		for (ch = 0; ch < rec->voices; ch++)
			stop_voice(rec, ch); // to be sure
		if (rec->dram_opened)
			emu8k_close_dram(rec->emu);
		snd_util_mem_free(rec->emu->memhdr, rec->block);
		rec->block = NULL;
	}
	return 0;
}

/*
 */
static int emu8k_pcm_prepare(struct snd_pcm_substream *subs)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;

	rec->pitch = 0xe000 + calc_rate_offset(subs->runtime->rate);
	rec->last_ptr = 0;
	rec->period_pos = 0;

	rec->buf_size = subs->runtime->buffer_size;
	rec->period_size = subs->runtime->period_size;
	rec->voices = subs->runtime->channels;
	rec->loop_start[0] = rec->offset + LOOP_BLANK_SIZE;
	if (rec->voices > 1)
		rec->loop_start[1] = rec->loop_start[0] + rec->buf_size + LOOP_BLANK_SIZE;
	if (rec->voices > 1) {
		rec->panning[0] = 0xff;
		rec->panning[1] = 0x00;
	} else
		rec->panning[0] = 0x80;

	if (! rec->dram_opened) {
		int err, i, ch;

		snd_emux_terminate_all(rec->emu->emu);
		err = emu8k_open_dram_for_pcm(rec->emu, rec->voices);
		if (err)
			return err;
		rec->dram_opened = 1;

		/* clear loop blanks */
		snd_emu8000_write_wait(rec->emu, 0);
		EMU8000_SMALW_WRITE(rec->emu, rec->offset);
		for (i = 0; i < LOOP_BLANK_SIZE; i++)
			EMU8000_SMLD_WRITE(rec->emu, 0);
		for (ch = 0; ch < rec->voices; ch++) {
			EMU8000_SMALW_WRITE(rec->emu, rec->loop_start[ch] + rec->buf_size);
			for (i = 0; i < LOOP_BLANK_SIZE; i++)
				EMU8000_SMLD_WRITE(rec->emu, 0);
		}
	}

	setup_voice(rec, 0);
	if (rec->voices > 1)
		setup_voice(rec, 1);
	return 0;
}

static snd_pcm_uframes_t emu8k_pcm_pointer(struct snd_pcm_substream *subs)
{
	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
	if (rec->running)
		return emu8k_get_curpos(rec, 0);
	return 0;
}


static const struct snd_pcm_ops emu8k_pcm_ops = {
	.open =		emu8k_pcm_open,
	.close =	emu8k_pcm_close,
	.hw_params =	emu8k_pcm_hw_params,
	.hw_free =	emu8k_pcm_hw_free,
	.prepare =	emu8k_pcm_prepare,
	.trigger =	emu8k_pcm_trigger,
	.pointer =	emu8k_pcm_pointer,
	.copy_user =	emu8k_pcm_copy,
	.copy_kernel =	emu8k_pcm_copy_kernel,
	.fill_silence =	emu8k_pcm_silence,
};


static void snd_emu8000_pcm_free(struct snd_pcm *pcm)
{
	struct snd_emu8000 *emu = pcm->private_data;
	emu->pcm = NULL;
}

int snd_emu8000_pcm_new(struct snd_card *card, struct snd_emu8000 *emu, int index)
{
	struct snd_pcm *pcm;
	int err;

	err = snd_pcm_new(card, "Emu8000 PCM", index, 1, 0, &pcm);
	if (err < 0)
		return err;
	pcm->private_data = emu;
	pcm->private_free = snd_emu8000_pcm_free;
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &emu8k_pcm_ops);
	emu->pcm = pcm;

	snd_device_register(card, pcm);

	return 0;
}