xref: /linux/sound/isa/sb/emu8000_pcm.c (revision f2527d8f566a45fa00ee5abd04d1c9476d4d704f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * pcm emulation on emu8000 wavetable
4  *
5  *  Copyright (C) 2002 Takashi Iwai <tiwai@suse.de>
6  */
7 
8 #include "emu8000_local.h"
9 
10 #include <linux/sched/signal.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <sound/initval.h>
14 #include <sound/pcm.h>
15 
16 /*
17  * define the following if you want to use this pcm with non-interleaved mode
18  */
19 /* #define USE_NONINTERLEAVE */
20 
21 /* NOTE: for using the non-interleaved mode with alsa-lib, you have to set
22  * mmap_emulation flag to 1 in your .asoundrc, such like
23  *
24  *	pcm.emu8k {
25  *		type plug
26  *		slave.pcm {
27  *			type hw
28  *			card 0
29  *			device 1
30  *			mmap_emulation 1
31  *		}
32  *	}
33  *
34  * besides, for the time being, the non-interleaved mode doesn't work well on
35  * alsa-lib...
36  */
37 
38 
39 struct snd_emu8k_pcm {
40 	struct snd_emu8000 *emu;
41 	struct snd_pcm_substream *substream;
42 
43 	unsigned int allocated_bytes;
44 	struct snd_util_memblk *block;
45 	unsigned int offset;
46 	unsigned int buf_size;
47 	unsigned int period_size;
48 	unsigned int loop_start[2];
49 	unsigned int pitch;
50 	int panning[2];
51 	int last_ptr;
52 	int period_pos;
53 	int voices;
54 	unsigned int dram_opened: 1;
55 	unsigned int running: 1;
56 	unsigned int timer_running: 1;
57 	struct timer_list timer;
58 	spinlock_t timer_lock;
59 };
60 
61 #define LOOP_BLANK_SIZE		8
62 
63 
64 /*
65  * open up channels for the simultaneous data transfer and playback
66  */
67 static int
68 emu8k_open_dram_for_pcm(struct snd_emu8000 *emu, int channels)
69 {
70 	int i;
71 
72 	/* reserve up to 2 voices for playback */
73 	snd_emux_lock_voice(emu->emu, 0);
74 	if (channels > 1)
75 		snd_emux_lock_voice(emu->emu, 1);
76 
77 	/* reserve 28 voices for loading */
78 	for (i = channels + 1; i < EMU8000_DRAM_VOICES; i++) {
79 		unsigned int mode = EMU8000_RAM_WRITE;
80 		snd_emux_lock_voice(emu->emu, i);
81 #ifndef USE_NONINTERLEAVE
82 		if (channels > 1 && (i & 1) != 0)
83 			mode |= EMU8000_RAM_RIGHT;
84 #endif
85 		snd_emu8000_dma_chan(emu, i, mode);
86 	}
87 
88 	/* assign voice 31 and 32 to ROM */
89 	EMU8000_VTFT_WRITE(emu, 30, 0);
90 	EMU8000_PSST_WRITE(emu, 30, 0x1d8);
91 	EMU8000_CSL_WRITE(emu, 30, 0x1e0);
92 	EMU8000_CCCA_WRITE(emu, 30, 0x1d8);
93 	EMU8000_VTFT_WRITE(emu, 31, 0);
94 	EMU8000_PSST_WRITE(emu, 31, 0x1d8);
95 	EMU8000_CSL_WRITE(emu, 31, 0x1e0);
96 	EMU8000_CCCA_WRITE(emu, 31, 0x1d8);
97 
98 	return 0;
99 }
100 
101 /*
102  */
103 static void
104 snd_emu8000_write_wait(struct snd_emu8000 *emu, int can_schedule)
105 {
106 	while ((EMU8000_SMALW_READ(emu) & 0x80000000) != 0) {
107 		if (can_schedule) {
108 			schedule_timeout_interruptible(1);
109 			if (signal_pending(current))
110 				break;
111 		}
112 	}
113 }
114 
115 /*
116  * close all channels
117  */
118 static void
119 emu8k_close_dram(struct snd_emu8000 *emu)
120 {
121 	int i;
122 
123 	for (i = 0; i < 2; i++)
124 		snd_emux_unlock_voice(emu->emu, i);
125 	for (; i < EMU8000_DRAM_VOICES; i++) {
126 		snd_emu8000_dma_chan(emu, i, EMU8000_RAM_CLOSE);
127 		snd_emux_unlock_voice(emu->emu, i);
128 	}
129 }
130 
131 /*
132  * convert Hz to AWE32 rate offset (see emux/soundfont.c)
133  */
134 
135 #define OFFSET_SAMPLERATE	1011119		/* base = 44100 */
136 #define SAMPLERATE_RATIO	4096
137 
138 static int calc_rate_offset(int hz)
139 {
140 	return snd_sf_linear_to_log(hz, OFFSET_SAMPLERATE, SAMPLERATE_RATIO);
141 }
142 
143 
144 /*
145  */
146 
147 static const struct snd_pcm_hardware emu8k_pcm_hw = {
148 #ifdef USE_NONINTERLEAVE
149 	.info =			SNDRV_PCM_INFO_NONINTERLEAVED,
150 #else
151 	.info =			SNDRV_PCM_INFO_INTERLEAVED,
152 #endif
153 	.formats =		SNDRV_PCM_FMTBIT_S16_LE,
154 	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
155 	.rate_min =		4000,
156 	.rate_max =		48000,
157 	.channels_min =		1,
158 	.channels_max =		2,
159 	.buffer_bytes_max =	(128*1024),
160 	.period_bytes_min =	1024,
161 	.period_bytes_max =	(128*1024),
162 	.periods_min =		2,
163 	.periods_max =		1024,
164 	.fifo_size =		0,
165 
166 };
167 
168 /*
169  * get the current position at the given channel from CCCA register
170  */
171 static inline int emu8k_get_curpos(struct snd_emu8k_pcm *rec, int ch)
172 {
173 	int val = EMU8000_CCCA_READ(rec->emu, ch) & 0xfffffff;
174 	val -= rec->loop_start[ch] - 1;
175 	return val;
176 }
177 
178 
179 /*
180  * timer interrupt handler
181  * check the current position and update the period if necessary.
182  */
183 static void emu8k_pcm_timer_func(struct timer_list *t)
184 {
185 	struct snd_emu8k_pcm *rec = from_timer(rec, t, timer);
186 	int ptr, delta;
187 
188 	spin_lock(&rec->timer_lock);
189 	/* update the current pointer */
190 	ptr = emu8k_get_curpos(rec, 0);
191 	if (ptr < rec->last_ptr)
192 		delta = ptr + rec->buf_size - rec->last_ptr;
193 	else
194 		delta = ptr - rec->last_ptr;
195 	rec->period_pos += delta;
196 	rec->last_ptr = ptr;
197 
198 	/* reprogram timer */
199 	mod_timer(&rec->timer, jiffies + 1);
200 
201 	/* update period */
202 	if (rec->period_pos >= (int)rec->period_size) {
203 		rec->period_pos %= rec->period_size;
204 		spin_unlock(&rec->timer_lock);
205 		snd_pcm_period_elapsed(rec->substream);
206 		return;
207 	}
208 	spin_unlock(&rec->timer_lock);
209 }
210 
211 
212 /*
213  * open pcm
214  * creating an instance here
215  */
216 static int emu8k_pcm_open(struct snd_pcm_substream *subs)
217 {
218 	struct snd_emu8000 *emu = snd_pcm_substream_chip(subs);
219 	struct snd_emu8k_pcm *rec;
220 	struct snd_pcm_runtime *runtime = subs->runtime;
221 
222 	rec = kzalloc(sizeof(*rec), GFP_KERNEL);
223 	if (! rec)
224 		return -ENOMEM;
225 
226 	rec->emu = emu;
227 	rec->substream = subs;
228 	runtime->private_data = rec;
229 
230 	spin_lock_init(&rec->timer_lock);
231 	timer_setup(&rec->timer, emu8k_pcm_timer_func, 0);
232 
233 	runtime->hw = emu8k_pcm_hw;
234 	runtime->hw.buffer_bytes_max = emu->mem_size - LOOP_BLANK_SIZE * 3;
235 	runtime->hw.period_bytes_max = runtime->hw.buffer_bytes_max / 2;
236 
237 	/* use timer to update periods.. (specified in msec) */
238 	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
239 				     DIV_ROUND_UP(1000000, HZ), UINT_MAX);
240 
241 	return 0;
242 }
243 
244 static int emu8k_pcm_close(struct snd_pcm_substream *subs)
245 {
246 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
247 	kfree(rec);
248 	subs->runtime->private_data = NULL;
249 	return 0;
250 }
251 
252 /*
253  * calculate pitch target
254  */
255 static int calc_pitch_target(int pitch)
256 {
257 	int ptarget = 1 << (pitch >> 12);
258 	if (pitch & 0x800) ptarget += (ptarget * 0x102e) / 0x2710;
259 	if (pitch & 0x400) ptarget += (ptarget * 0x764) / 0x2710;
260 	if (pitch & 0x200) ptarget += (ptarget * 0x389) / 0x2710;
261 	ptarget += (ptarget >> 1);
262 	if (ptarget > 0xffff) ptarget = 0xffff;
263 	return ptarget;
264 }
265 
266 /*
267  * set up the voice
268  */
269 static void setup_voice(struct snd_emu8k_pcm *rec, int ch)
270 {
271 	struct snd_emu8000 *hw = rec->emu;
272 	unsigned int temp;
273 
274 	/* channel to be silent and idle */
275 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x0080);
276 	EMU8000_VTFT_WRITE(hw, ch, 0x0000FFFF);
277 	EMU8000_CVCF_WRITE(hw, ch, 0x0000FFFF);
278 	EMU8000_PTRX_WRITE(hw, ch, 0);
279 	EMU8000_CPF_WRITE(hw, ch, 0);
280 
281 	/* pitch offset */
282 	EMU8000_IP_WRITE(hw, ch, rec->pitch);
283 	/* set envelope parameters */
284 	EMU8000_ENVVAL_WRITE(hw, ch, 0x8000);
285 	EMU8000_ATKHLD_WRITE(hw, ch, 0x7f7f);
286 	EMU8000_DCYSUS_WRITE(hw, ch, 0x7f7f);
287 	EMU8000_ENVVOL_WRITE(hw, ch, 0x8000);
288 	EMU8000_ATKHLDV_WRITE(hw, ch, 0x7f7f);
289 	/* decay/sustain parameter for volume envelope is used
290 	   for triggerg the voice */
291 	/* modulation envelope heights */
292 	EMU8000_PEFE_WRITE(hw, ch, 0x0);
293 	/* lfo1/2 delay */
294 	EMU8000_LFO1VAL_WRITE(hw, ch, 0x8000);
295 	EMU8000_LFO2VAL_WRITE(hw, ch, 0x8000);
296 	/* lfo1 pitch & cutoff shift */
297 	EMU8000_FMMOD_WRITE(hw, ch, 0);
298 	/* lfo1 volume & freq */
299 	EMU8000_TREMFRQ_WRITE(hw, ch, 0);
300 	/* lfo2 pitch & freq */
301 	EMU8000_FM2FRQ2_WRITE(hw, ch, 0);
302 	/* pan & loop start */
303 	temp = rec->panning[ch];
304 	temp = (temp <<24) | ((unsigned int)rec->loop_start[ch] - 1);
305 	EMU8000_PSST_WRITE(hw, ch, temp);
306 	/* chorus & loop end (chorus 8bit, MSB) */
307 	temp = 0; // chorus
308 	temp = (temp << 24) | ((unsigned int)rec->loop_start[ch] + rec->buf_size - 1);
309 	EMU8000_CSL_WRITE(hw, ch, temp);
310 	/* Q & current address (Q 4bit value, MSB) */
311 	temp = 0; // filterQ
312 	temp = (temp << 28) | ((unsigned int)rec->loop_start[ch] - 1);
313 	EMU8000_CCCA_WRITE(hw, ch, temp);
314 	/* clear unknown registers */
315 	EMU8000_00A0_WRITE(hw, ch, 0);
316 	EMU8000_0080_WRITE(hw, ch, 0);
317 }
318 
319 /*
320  * trigger the voice
321  */
322 static void start_voice(struct snd_emu8k_pcm *rec, int ch)
323 {
324 	unsigned long flags;
325 	struct snd_emu8000 *hw = rec->emu;
326 	unsigned int temp, aux;
327 	int pt = calc_pitch_target(rec->pitch);
328 
329 	/* cutoff and volume */
330 	EMU8000_IFATN_WRITE(hw, ch, 0xff00);
331 	EMU8000_VTFT_WRITE(hw, ch, 0xffff);
332 	EMU8000_CVCF_WRITE(hw, ch, 0xffff);
333 	/* trigger envelope */
334 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x7f7f);
335 	/* set reverb and pitch target */
336 	temp = 0; // reverb
337 	if (rec->panning[ch] == 0)
338 		aux = 0xff;
339 	else
340 		aux = (-rec->panning[ch]) & 0xff;
341 	temp = (temp << 8) | (pt << 16) | aux;
342 	EMU8000_PTRX_WRITE(hw, ch, temp);
343 	EMU8000_CPF_WRITE(hw, ch, pt << 16);
344 
345 	/* start timer */
346 	spin_lock_irqsave(&rec->timer_lock, flags);
347 	if (! rec->timer_running) {
348 		mod_timer(&rec->timer, jiffies + 1);
349 		rec->timer_running = 1;
350 	}
351 	spin_unlock_irqrestore(&rec->timer_lock, flags);
352 }
353 
354 /*
355  * stop the voice immediately
356  */
357 static void stop_voice(struct snd_emu8k_pcm *rec, int ch)
358 {
359 	unsigned long flags;
360 	struct snd_emu8000 *hw = rec->emu;
361 
362 	EMU8000_DCYSUSV_WRITE(hw, ch, 0x807F);
363 
364 	/* stop timer */
365 	spin_lock_irqsave(&rec->timer_lock, flags);
366 	if (rec->timer_running) {
367 		del_timer(&rec->timer);
368 		rec->timer_running = 0;
369 	}
370 	spin_unlock_irqrestore(&rec->timer_lock, flags);
371 }
372 
373 static int emu8k_pcm_trigger(struct snd_pcm_substream *subs, int cmd)
374 {
375 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
376 	int ch;
377 
378 	switch (cmd) {
379 	case SNDRV_PCM_TRIGGER_START:
380 		for (ch = 0; ch < rec->voices; ch++)
381 			start_voice(rec, ch);
382 		rec->running = 1;
383 		break;
384 	case SNDRV_PCM_TRIGGER_STOP:
385 		rec->running = 0;
386 		for (ch = 0; ch < rec->voices; ch++)
387 			stop_voice(rec, ch);
388 		break;
389 	default:
390 		return -EINVAL;
391 	}
392 	return 0;
393 }
394 
395 
396 /*
397  * copy / silence ops
398  */
399 
400 /*
401  * this macro should be inserted in the copy/silence loops
402  * to reduce the latency.  without this, the system will hang up
403  * during the whole loop.
404  */
405 #define CHECK_SCHEDULER() \
406 do { \
407 	cond_resched();\
408 	if (signal_pending(current))\
409 		return -EAGAIN;\
410 } while (0)
411 
412 enum {
413 	COPY_USER, COPY_KERNEL, FILL_SILENCE,
414 };
415 
416 #define GET_VAL(sval, buf, mode)					\
417 	do {								\
418 		switch (mode) {						\
419 		case FILL_SILENCE:					\
420 			sval = 0;					\
421 			break;						\
422 		case COPY_KERNEL:					\
423 			sval = *buf++;					\
424 			break;						\
425 		default:						\
426 			if (get_user(sval, (unsigned short __user *)buf)) \
427 				return -EFAULT;				\
428 			buf++;						\
429 			break;						\
430 		}							\
431 	} while (0)
432 
433 #ifdef USE_NONINTERLEAVE
434 
435 #define LOOP_WRITE(rec, offset, _buf, count, mode)		\
436 	do {							\
437 		struct snd_emu8000 *emu = (rec)->emu;		\
438 		unsigned short *buf = (__force unsigned short *)(_buf); \
439 		snd_emu8000_write_wait(emu, 1);			\
440 		EMU8000_SMALW_WRITE(emu, offset);		\
441 		while (count > 0) {				\
442 			unsigned short sval;			\
443 			CHECK_SCHEDULER();			\
444 			GET_VAL(sval, buf, mode);		\
445 			EMU8000_SMLD_WRITE(emu, sval);		\
446 			count--;				\
447 		}						\
448 	} while (0)
449 
450 /* copy one channel block */
451 static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
452 			  int voice, unsigned long pos,
453 			  void __user *src, unsigned long count)
454 {
455 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
456 
457 	/* convert to word unit */
458 	pos = (pos << 1) + rec->loop_start[voice];
459 	count <<= 1;
460 	LOOP_WRITE(rec, pos, src, count, COPY_USER);
461 	return 0;
462 }
463 
464 static int emu8k_pcm_copy_kernel(struct snd_pcm_substream *subs,
465 				 int voice, unsigned long pos,
466 				 void *src, unsigned long count)
467 {
468 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
469 
470 	/* convert to word unit */
471 	pos = (pos << 1) + rec->loop_start[voice];
472 	count <<= 1;
473 	LOOP_WRITE(rec, pos, src, count, COPY_KERNEL);
474 	return 0;
475 }
476 
477 /* make a channel block silence */
478 static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
479 			     int voice, unsigned long pos, unsigned long count)
480 {
481 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
482 
483 	/* convert to word unit */
484 	pos = (pos << 1) + rec->loop_start[voice];
485 	count <<= 1;
486 	LOOP_WRITE(rec, pos, NULL, count, FILL_SILENCE);
487 	return 0;
488 }
489 
490 #else /* interleave */
491 
492 #define LOOP_WRITE(rec, pos, _buf, count, mode)				\
493 	do {								\
494 		struct snd_emu8000 *emu = rec->emu;			\
495 		unsigned short *buf = (__force unsigned short *)(_buf);	\
496 		snd_emu8000_write_wait(emu, 1);				\
497 		EMU8000_SMALW_WRITE(emu, pos + rec->loop_start[0]);	\
498 		if (rec->voices > 1)					\
499 			EMU8000_SMARW_WRITE(emu, pos + rec->loop_start[1]); \
500 		while (count > 0) {					\
501 			unsigned short sval;				\
502 			CHECK_SCHEDULER();				\
503 			GET_VAL(sval, buf, mode);			\
504 			EMU8000_SMLD_WRITE(emu, sval);			\
505 			if (rec->voices > 1) {				\
506 				CHECK_SCHEDULER();			\
507 				GET_VAL(sval, buf, mode);		\
508 				EMU8000_SMRD_WRITE(emu, sval);		\
509 			}						\
510 			count--;					\
511 		}							\
512 	} while (0)
513 
514 
515 /*
516  * copy the interleaved data can be done easily by using
517  * DMA "left" and "right" channels on emu8k engine.
518  */
519 static int emu8k_pcm_copy(struct snd_pcm_substream *subs,
520 			  int voice, unsigned long pos,
521 			  void __user *src, unsigned long count)
522 {
523 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
524 
525 	/* convert to frames */
526 	pos = bytes_to_frames(subs->runtime, pos);
527 	count = bytes_to_frames(subs->runtime, count);
528 	LOOP_WRITE(rec, pos, src, count, COPY_USER);
529 	return 0;
530 }
531 
532 static int emu8k_pcm_copy_kernel(struct snd_pcm_substream *subs,
533 				 int voice, unsigned long pos,
534 				 void *src, unsigned long count)
535 {
536 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
537 
538 	/* convert to frames */
539 	pos = bytes_to_frames(subs->runtime, pos);
540 	count = bytes_to_frames(subs->runtime, count);
541 	LOOP_WRITE(rec, pos, src, count, COPY_KERNEL);
542 	return 0;
543 }
544 
545 static int emu8k_pcm_silence(struct snd_pcm_substream *subs,
546 			     int voice, unsigned long pos, unsigned long count)
547 {
548 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
549 
550 	/* convert to frames */
551 	pos = bytes_to_frames(subs->runtime, pos);
552 	count = bytes_to_frames(subs->runtime, count);
553 	LOOP_WRITE(rec, pos, NULL, count, FILL_SILENCE);
554 	return 0;
555 }
556 #endif
557 
558 
559 /*
560  * allocate a memory block
561  */
562 static int emu8k_pcm_hw_params(struct snd_pcm_substream *subs,
563 			       struct snd_pcm_hw_params *hw_params)
564 {
565 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
566 
567 	if (rec->block) {
568 		/* reallocation - release the old block */
569 		snd_util_mem_free(rec->emu->memhdr, rec->block);
570 		rec->block = NULL;
571 	}
572 
573 	rec->allocated_bytes = params_buffer_bytes(hw_params) + LOOP_BLANK_SIZE * 4;
574 	rec->block = snd_util_mem_alloc(rec->emu->memhdr, rec->allocated_bytes);
575 	if (! rec->block)
576 		return -ENOMEM;
577 	rec->offset = EMU8000_DRAM_OFFSET + (rec->block->offset >> 1); /* in word */
578 	/* at least dma_bytes must be set for non-interleaved mode */
579 	subs->dma_buffer.bytes = params_buffer_bytes(hw_params);
580 
581 	return 0;
582 }
583 
584 /*
585  * free the memory block
586  */
587 static int emu8k_pcm_hw_free(struct snd_pcm_substream *subs)
588 {
589 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
590 
591 	if (rec->block) {
592 		int ch;
593 		for (ch = 0; ch < rec->voices; ch++)
594 			stop_voice(rec, ch); // to be sure
595 		if (rec->dram_opened)
596 			emu8k_close_dram(rec->emu);
597 		snd_util_mem_free(rec->emu->memhdr, rec->block);
598 		rec->block = NULL;
599 	}
600 	return 0;
601 }
602 
603 /*
604  */
605 static int emu8k_pcm_prepare(struct snd_pcm_substream *subs)
606 {
607 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
608 
609 	rec->pitch = 0xe000 + calc_rate_offset(subs->runtime->rate);
610 	rec->last_ptr = 0;
611 	rec->period_pos = 0;
612 
613 	rec->buf_size = subs->runtime->buffer_size;
614 	rec->period_size = subs->runtime->period_size;
615 	rec->voices = subs->runtime->channels;
616 	rec->loop_start[0] = rec->offset + LOOP_BLANK_SIZE;
617 	if (rec->voices > 1)
618 		rec->loop_start[1] = rec->loop_start[0] + rec->buf_size + LOOP_BLANK_SIZE;
619 	if (rec->voices > 1) {
620 		rec->panning[0] = 0xff;
621 		rec->panning[1] = 0x00;
622 	} else
623 		rec->panning[0] = 0x80;
624 
625 	if (! rec->dram_opened) {
626 		int err, i, ch;
627 
628 		snd_emux_terminate_all(rec->emu->emu);
629 		err = emu8k_open_dram_for_pcm(rec->emu, rec->voices);
630 		if (err)
631 			return err;
632 		rec->dram_opened = 1;
633 
634 		/* clear loop blanks */
635 		snd_emu8000_write_wait(rec->emu, 0);
636 		EMU8000_SMALW_WRITE(rec->emu, rec->offset);
637 		for (i = 0; i < LOOP_BLANK_SIZE; i++)
638 			EMU8000_SMLD_WRITE(rec->emu, 0);
639 		for (ch = 0; ch < rec->voices; ch++) {
640 			EMU8000_SMALW_WRITE(rec->emu, rec->loop_start[ch] + rec->buf_size);
641 			for (i = 0; i < LOOP_BLANK_SIZE; i++)
642 				EMU8000_SMLD_WRITE(rec->emu, 0);
643 		}
644 	}
645 
646 	setup_voice(rec, 0);
647 	if (rec->voices > 1)
648 		setup_voice(rec, 1);
649 	return 0;
650 }
651 
652 static snd_pcm_uframes_t emu8k_pcm_pointer(struct snd_pcm_substream *subs)
653 {
654 	struct snd_emu8k_pcm *rec = subs->runtime->private_data;
655 	if (rec->running)
656 		return emu8k_get_curpos(rec, 0);
657 	return 0;
658 }
659 
660 
661 static const struct snd_pcm_ops emu8k_pcm_ops = {
662 	.open =		emu8k_pcm_open,
663 	.close =	emu8k_pcm_close,
664 	.hw_params =	emu8k_pcm_hw_params,
665 	.hw_free =	emu8k_pcm_hw_free,
666 	.prepare =	emu8k_pcm_prepare,
667 	.trigger =	emu8k_pcm_trigger,
668 	.pointer =	emu8k_pcm_pointer,
669 	.copy_user =	emu8k_pcm_copy,
670 	.copy_kernel =	emu8k_pcm_copy_kernel,
671 	.fill_silence =	emu8k_pcm_silence,
672 };
673 
674 
675 static void snd_emu8000_pcm_free(struct snd_pcm *pcm)
676 {
677 	struct snd_emu8000 *emu = pcm->private_data;
678 	emu->pcm = NULL;
679 }
680 
681 int snd_emu8000_pcm_new(struct snd_card *card, struct snd_emu8000 *emu, int index)
682 {
683 	struct snd_pcm *pcm;
684 	int err;
685 
686 	err = snd_pcm_new(card, "Emu8000 PCM", index, 1, 0, &pcm);
687 	if (err < 0)
688 		return err;
689 	pcm->private_data = emu;
690 	pcm->private_free = snd_emu8000_pcm_free;
691 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &emu8k_pcm_ops);
692 	emu->pcm = pcm;
693 
694 	snd_device_register(card, pcm);
695 
696 	return 0;
697 }
698