1 /*-
2 * Copyright (c) 1999 Cameron Grant <cg@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <dev/sound/pcm/sound.h>
28
29 #include "feeder_if.h"
30
31 SND_DECLARE_FILE("$FreeBSD$");
32
33 struct snd_dbuf *
34 sndbuf_create(device_t dev, char *drv, char *desc, struct pcm_channel *channel)
35 {
36 struct snd_dbuf *b;
37
38 b = malloc(sizeof(*b), M_DEVBUF, M_WAITOK | M_ZERO);
39 snprintf(b->name, SNDBUF_NAMELEN, "%s:%s", drv, desc);
40 b->dev = dev;
41 b->channel = channel;
42
43 return b;
44 }
45
46 void
47 sndbuf_destroy(struct snd_dbuf *b)
48 {
49 sndbuf_free(b);
50 free(b, M_DEVBUF);
51 }
52
53 bus_addr_t
54 sndbuf_getbufaddr(struct snd_dbuf *buf)
55 {
56 return (buf->buf_addr);
57 }
58
59 static void
60 sndbuf_setmap(void *arg, bus_dma_segment_t *segs, int nseg, int error)
61 {
62 struct snd_dbuf *b = (struct snd_dbuf *)arg;
63
64 if (bootverbose) {
65 device_printf(b->dev, "sndbuf_setmap %lx, %lx; ",
66 (u_long)segs[0].ds_addr, (u_long)segs[0].ds_len);
67 printf("%p -> %lx\n", b->buf, (u_long)segs[0].ds_addr);
68 }
69 if (error == 0)
70 b->buf_addr = segs[0].ds_addr;
71 else
72 b->buf_addr = 0;
73 }
74
75 /*
76 * Allocate memory for DMA buffer. If the device does not use DMA transfers,
77 * the driver can call malloc(9) and sndbuf_setup() itself.
78 */
79
80 int
81 sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, int dmaflags,
82 unsigned int size)
83 {
84 int ret;
85
86 b->dmatag = dmatag;
87 b->dmaflags = dmaflags | BUS_DMA_NOWAIT;
88 b->maxsize = size;
89 b->bufsize = b->maxsize;
90 b->buf_addr = 0;
91 b->flags |= SNDBUF_F_MANAGED;
92 if (bus_dmamem_alloc(b->dmatag, (void **)&b->buf, b->dmaflags,
93 &b->dmamap)) {
94 sndbuf_free(b);
95 return (ENOMEM);
96 }
97 if (bus_dmamap_load(b->dmatag, b->dmamap, b->buf, b->maxsize,
98 sndbuf_setmap, b, 0) != 0 || b->buf_addr == 0) {
99 sndbuf_free(b);
100 return (ENOMEM);
101 }
102
103 ret = sndbuf_resize(b, 2, b->maxsize / 2);
104 if (ret != 0)
105 sndbuf_free(b);
106
107 return (ret);
108 }
109
110 int
111 sndbuf_setup(struct snd_dbuf *b, void *buf, unsigned int size)
112 {
113 b->flags &= ~SNDBUF_F_MANAGED;
114 if (buf)
115 b->flags |= SNDBUF_F_MANAGED;
116 b->buf = buf;
117 b->maxsize = size;
118 b->bufsize = b->maxsize;
119 return sndbuf_resize(b, 2, b->maxsize / 2);
120 }
121
122 void
123 sndbuf_free(struct snd_dbuf *b)
124 {
125 if (b->tmpbuf)
126 free(b->tmpbuf, M_DEVBUF);
127
128 if (b->shadbuf)
129 free(b->shadbuf, M_DEVBUF);
130
131 if (b->buf) {
132 if (b->flags & SNDBUF_F_MANAGED) {
133 if (b->dmamap)
134 bus_dmamap_unload(b->dmatag, b->dmamap);
135 if (b->dmatag)
136 bus_dmamem_free(b->dmatag, b->buf, b->dmamap);
137 } else
138 free(b->buf, M_DEVBUF);
139 }
140
141 b->tmpbuf = NULL;
142 b->shadbuf = NULL;
143 b->buf = NULL;
144 b->sl = 0;
145 b->dmatag = NULL;
146 b->dmamap = NULL;
147 }
148
149 #define SNDBUF_CACHE_SHIFT 5
150
151 int
152 sndbuf_resize(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
153 {
154 unsigned int bufsize, allocsize;
155 u_int8_t *tmpbuf;
156
157 chn_lock(b->channel);
158 if (b->maxsize == 0)
159 goto out;
160 if (blkcnt == 0)
161 blkcnt = b->blkcnt;
162 if (blksz == 0)
163 blksz = b->blksz;
164 if (blkcnt < 2 || blksz < 16 || (blkcnt * blksz) > b->maxsize) {
165 chn_unlock(b->channel);
166 return EINVAL;
167 }
168 if (blkcnt == b->blkcnt && blksz == b->blksz)
169 goto out;
170
171 bufsize = blkcnt * blksz;
172
173 if (bufsize > b->allocsize ||
174 bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
175 allocsize = round_page(bufsize);
176 chn_unlock(b->channel);
177 tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
178 chn_lock(b->channel);
179 if (snd_verbose > 3)
180 printf("%s(): b=%p %p -> %p [%d -> %d : %d]\n",
181 __func__, b, b->tmpbuf, tmpbuf,
182 b->allocsize, allocsize, bufsize);
183 if (b->tmpbuf != NULL)
184 free(b->tmpbuf, M_DEVBUF);
185 b->tmpbuf = tmpbuf;
186 b->allocsize = allocsize;
187 } else if (snd_verbose > 3)
188 printf("%s(): b=%p %d [%d] NOCHANGE\n",
189 __func__, b, b->allocsize, b->bufsize);
190
191 b->blkcnt = blkcnt;
192 b->blksz = blksz;
193 b->bufsize = bufsize;
194
195 sndbuf_reset(b);
196 out:
197 chn_unlock(b->channel);
198 return 0;
199 }
200
201 int
202 sndbuf_remalloc(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
203 {
204 unsigned int bufsize, allocsize;
205 u_int8_t *buf, *tmpbuf, *shadbuf;
206
207 if (blkcnt < 2 || blksz < 16)
208 return EINVAL;
209
210 bufsize = blksz * blkcnt;
211
212 if (bufsize > b->allocsize ||
213 bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
214 allocsize = round_page(bufsize);
215 chn_unlock(b->channel);
216 buf = malloc(allocsize, M_DEVBUF, M_WAITOK);
217 tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
218 shadbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
219 chn_lock(b->channel);
220 if (b->buf != NULL)
221 free(b->buf, M_DEVBUF);
222 b->buf = buf;
223 if (b->tmpbuf != NULL)
224 free(b->tmpbuf, M_DEVBUF);
225 b->tmpbuf = tmpbuf;
226 if (b->shadbuf != NULL)
227 free(b->shadbuf, M_DEVBUF);
228 b->shadbuf = shadbuf;
229 if (snd_verbose > 3)
230 printf("%s(): b=%p %d -> %d [%d]\n",
231 __func__, b, b->allocsize, allocsize, bufsize);
232 b->allocsize = allocsize;
233 } else if (snd_verbose > 3)
234 printf("%s(): b=%p %d [%d] NOCHANGE\n",
235 __func__, b, b->allocsize, b->bufsize);
236
237 b->blkcnt = blkcnt;
238 b->blksz = blksz;
239 b->bufsize = bufsize;
240 b->maxsize = bufsize;
241 b->sl = bufsize;
242
243 sndbuf_reset(b);
244
245 return 0;
246 }
247
248 /**
249 * @brief Zero out space in buffer free area
250 *
251 * This function clears a chunk of @c length bytes in the buffer free area
252 * (i.e., where the next write will be placed).
253 *
254 * @param b buffer context
255 * @param length number of bytes to blank
256 */
257 void
258 sndbuf_clear(struct snd_dbuf *b, unsigned int length)
259 {
260 int i;
261 u_char data, *p;
262
263 if (length == 0)
264 return;
265 if (length > b->bufsize)
266 length = b->bufsize;
267
268 data = sndbuf_zerodata(b->fmt);
269
270 i = sndbuf_getfreeptr(b);
271 p = sndbuf_getbuf(b);
272 while (length > 0) {
273 p[i] = data;
274 length--;
275 i++;
276 if (i >= b->bufsize)
277 i = 0;
278 }
279 }
280
281 /**
282 * @brief Zap buffer contents, resetting "ready area" fields
283 *
284 * @param b buffer context
285 */
286 void
287 sndbuf_fillsilence(struct snd_dbuf *b)
288 {
289 if (b->bufsize > 0)
290 memset(sndbuf_getbuf(b), sndbuf_zerodata(b->fmt), b->bufsize);
291 b->rp = 0;
292 b->rl = b->bufsize;
293 }
294
295 /**
296 * @brief Reset buffer w/o flushing statistics
297 *
298 * This function just zeroes out buffer contents and sets the "ready length"
299 * to zero. This was originally to facilitate minimal playback interruption
300 * (i.e., dropped samples) in SNDCTL_DSP_SILENCE/SKIP ioctls.
301 *
302 * @param b buffer context
303 */
304 void
305 sndbuf_softreset(struct snd_dbuf *b)
306 {
307 b->rl = 0;
308 if (b->buf && b->bufsize > 0)
309 sndbuf_clear(b, b->bufsize);
310 }
311
312 void
313 sndbuf_reset(struct snd_dbuf *b)
314 {
315 b->hp = 0;
316 b->rp = 0;
317 b->rl = 0;
318 b->dl = 0;
319 b->prev_total = 0;
320 b->total = 0;
321 b->xrun = 0;
322 if (b->buf && b->bufsize > 0)
323 sndbuf_clear(b, b->bufsize);
324 sndbuf_clearshadow(b);
325 }
326
327 u_int32_t
328 sndbuf_getfmt(struct snd_dbuf *b)
329 {
330 return b->fmt;
331 }
332
333 int
334 sndbuf_setfmt(struct snd_dbuf *b, u_int32_t fmt)
335 {
336 b->fmt = fmt;
337 b->bps = 1;
338 b->bps <<= (b->fmt & AFMT_STEREO)? 1 : 0;
339 if (b->fmt & AFMT_16BIT)
340 b->bps <<= 1;
341 else if (b->fmt & AFMT_24BIT)
342 b->bps *= 3;
343 else if (b->fmt & AFMT_32BIT)
344 b->bps <<= 2;
345 return 0;
346 }
347
348 unsigned int
349 sndbuf_getspd(struct snd_dbuf *b)
350 {
351 return b->spd;
352 }
353
354 void
355 sndbuf_setspd(struct snd_dbuf *b, unsigned int spd)
356 {
357 b->spd = spd;
358 }
359
360 unsigned int
361 sndbuf_getalign(struct snd_dbuf *b)
362 {
363 static int align[] = {0, 1, 1, 2, 2, 2, 2, 3};
364
365 return align[b->bps - 1];
366 }
367
368 unsigned int
369 sndbuf_getblkcnt(struct snd_dbuf *b)
370 {
371 return b->blkcnt;
372 }
373
374 void
375 sndbuf_setblkcnt(struct snd_dbuf *b, unsigned int blkcnt)
376 {
377 b->blkcnt = blkcnt;
378 }
379
380 unsigned int
381 sndbuf_getblksz(struct snd_dbuf *b)
382 {
383 return b->blksz;
384 }
385
386 void
387 sndbuf_setblksz(struct snd_dbuf *b, unsigned int blksz)
388 {
389 b->blksz = blksz;
390 }
391
392 unsigned int
393 sndbuf_getbps(struct snd_dbuf *b)
394 {
395 return b->bps;
396 }
397
398 void *
399 sndbuf_getbuf(struct snd_dbuf *b)
400 {
401 return b->buf;
402 }
403
404 void *
405 sndbuf_getbufofs(struct snd_dbuf *b, unsigned int ofs)
406 {
407 KASSERT(ofs < b->bufsize, ("%s: ofs invalid %d", __func__, ofs));
408
409 return b->buf + ofs;
410 }
411
412 unsigned int
413 sndbuf_getsize(struct snd_dbuf *b)
414 {
415 return b->bufsize;
416 }
417
418 unsigned int
419 sndbuf_getmaxsize(struct snd_dbuf *b)
420 {
421 return b->maxsize;
422 }
423
424 unsigned int
425 sndbuf_getallocsize(struct snd_dbuf *b)
426 {
427 return b->allocsize;
428 }
429
430 unsigned int
431 sndbuf_runsz(struct snd_dbuf *b)
432 {
433 return b->dl;
434 }
435
436 void
437 sndbuf_setrun(struct snd_dbuf *b, int go)
438 {
439 b->dl = go? b->blksz : 0;
440 }
441
442 struct selinfo *
443 sndbuf_getsel(struct snd_dbuf *b)
444 {
445 return &b->sel;
446 }
447
448 /************************************************************/
449 unsigned int
450 sndbuf_getxrun(struct snd_dbuf *b)
451 {
452 SNDBUF_LOCKASSERT(b);
453
454 return b->xrun;
455 }
456
457 void
458 sndbuf_setxrun(struct snd_dbuf *b, unsigned int xrun)
459 {
460 SNDBUF_LOCKASSERT(b);
461
462 b->xrun = xrun;
463 }
464
465 unsigned int
466 sndbuf_gethwptr(struct snd_dbuf *b)
467 {
468 SNDBUF_LOCKASSERT(b);
469
470 return b->hp;
471 }
472
473 void
474 sndbuf_sethwptr(struct snd_dbuf *b, unsigned int ptr)
475 {
476 SNDBUF_LOCKASSERT(b);
477
478 b->hp = ptr;
479 }
480
481 unsigned int
482 sndbuf_getready(struct snd_dbuf *b)
483 {
484 SNDBUF_LOCKASSERT(b);
485 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
486
487 return b->rl;
488 }
489
490 unsigned int
491 sndbuf_getreadyptr(struct snd_dbuf *b)
492 {
493 SNDBUF_LOCKASSERT(b);
494 KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
495
496 return b->rp;
497 }
498
499 unsigned int
500 sndbuf_getfree(struct snd_dbuf *b)
501 {
502 SNDBUF_LOCKASSERT(b);
503 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
504
505 return b->bufsize - b->rl;
506 }
507
508 unsigned int
509 sndbuf_getfreeptr(struct snd_dbuf *b)
510 {
511 SNDBUF_LOCKASSERT(b);
512 KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
513 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
514
515 return (b->rp + b->rl) % b->bufsize;
516 }
517
518 unsigned int
519 sndbuf_getblocks(struct snd_dbuf *b)
520 {
521 SNDBUF_LOCKASSERT(b);
522
523 return b->total / b->blksz;
524 }
525
526 unsigned int
527 sndbuf_getprevblocks(struct snd_dbuf *b)
528 {
529 SNDBUF_LOCKASSERT(b);
530
531 return b->prev_total / b->blksz;
532 }
533
534 unsigned int
535 sndbuf_gettotal(struct snd_dbuf *b)
536 {
537 SNDBUF_LOCKASSERT(b);
538
539 return b->total;
540 }
541
542 void
543 sndbuf_updateprevtotal(struct snd_dbuf *b)
544 {
545 SNDBUF_LOCKASSERT(b);
546
547 b->prev_total = b->total;
548 }
549
550 unsigned int
551 snd_xbytes(unsigned int v, unsigned int from, unsigned int to)
552 {
553 unsigned int w, x, y;
554
555 if (from == to)
556 return v;
557
558 if (from == 0 || to == 0 || v == 0)
559 return 0;
560
561 x = from;
562 y = to;
563 while (y != 0) {
564 w = x % y;
565 x = y;
566 y = w;
567 }
568 from /= x;
569 to /= x;
570
571 return (unsigned int)(((u_int64_t)v * to) / from);
572 }
573
574 unsigned int
575 sndbuf_xbytes(unsigned int v, struct snd_dbuf *from, struct snd_dbuf *to)
576 {
577 if (from == NULL || to == NULL || v == 0)
578 return 0;
579
580 return snd_xbytes(v, sndbuf_getbps(from) * sndbuf_getspd(from),
581 sndbuf_getbps(to) * sndbuf_getspd(to));
582 }
583
584 u_int8_t
585 sndbuf_zerodata(u_int32_t fmt)
586 {
587 if (fmt & AFMT_SIGNED)
588 return (0x00);
589 else if (fmt & AFMT_MU_LAW)
590 return (0x7f);
591 else if (fmt & AFMT_A_LAW)
592 return (0x55);
593 return (0x80);
594 }
595
596 /************************************************************/
597
598 /**
599 * @brief Acquire buffer space to extend ready area
600 *
601 * This function extends the ready area length by @c count bytes, and may
602 * optionally copy samples from another location stored in @c from. The
603 * counter @c snd_dbuf::total is also incremented by @c count bytes.
604 *
605 * @param b audio buffer
606 * @param from sample source (optional)
607 * @param count number of bytes to acquire
608 *
609 * @retval 0 Unconditional
610 */
611 int
612 sndbuf_acquire(struct snd_dbuf *b, u_int8_t *from, unsigned int count)
613 {
614 int l;
615
616 KASSERT(count <= sndbuf_getfree(b), ("%s: count %d > free %d", __func__, count, sndbuf_getfree(b)));
617 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
618 b->total += count;
619 if (from != NULL) {
620 while (count > 0) {
621 l = min(count, sndbuf_getsize(b) - sndbuf_getfreeptr(b));
622 bcopy(from, sndbuf_getbufofs(b, sndbuf_getfreeptr(b)), l);
623 from += l;
624 b->rl += l;
625 count -= l;
626 }
627 } else
628 b->rl += count;
629 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
630
631 return 0;
632 }
633
634 /**
635 * @brief Dispose samples from channel buffer, increasing size of ready area
636 *
637 * This function discards samples from the supplied buffer by advancing the
638 * ready area start pointer and decrementing the ready area length. If
639 * @c to is not NULL, then the discard samples will be copied to the location
640 * it points to.
641 *
642 * @param b PCM channel sound buffer
643 * @param to destination buffer (optional)
644 * @param count number of bytes to discard
645 *
646 * @returns 0 unconditionally
647 */
648 int
649 sndbuf_dispose(struct snd_dbuf *b, u_int8_t *to, unsigned int count)
650 {
651 int l;
652
653 KASSERT(count <= sndbuf_getready(b), ("%s: count %d > ready %d", __func__, count, sndbuf_getready(b)));
654 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
655 if (to != NULL) {
656 while (count > 0) {
657 l = min(count, sndbuf_getsize(b) - sndbuf_getreadyptr(b));
658 bcopy(sndbuf_getbufofs(b, sndbuf_getreadyptr(b)), to, l);
659 to += l;
660 b->rl -= l;
661 b->rp = (b->rp + l) % b->bufsize;
662 count -= l;
663 }
664 } else {
665 b->rl -= count;
666 b->rp = (b->rp + count) % b->bufsize;
667 }
668 KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
669
670 return 0;
671 }
672
673 /* count is number of bytes we want added to destination buffer */
674 int
675 sndbuf_feed(struct snd_dbuf *from, struct snd_dbuf *to, struct pcm_channel *channel, struct pcm_feeder *feeder, unsigned int count)
676 {
677 unsigned int cnt;
678
679 KASSERT(count > 0, ("can't feed 0 bytes"));
680
681 if (sndbuf_getfree(to) < count)
682 return EINVAL;
683
684 do {
685 cnt = FEEDER_FEED(feeder, channel, to->tmpbuf, count, from);
686 if (cnt) {
687 sndbuf_acquire(to, to->tmpbuf, cnt);
688 count -= cnt;
689 }
690 } while (count && cnt);
691
692 return 0;
693 }
694
695 /************************************************************/
696
697 void
698 sndbuf_dump(struct snd_dbuf *b, char *s, u_int32_t what)
699 {
700 printf("%s: [", s);
701 if (what & 0x01)
702 printf(" bufsize: %d, maxsize: %d", b->bufsize, b->maxsize);
703 if (what & 0x02)
704 printf(" dl: %d, rp: %d, rl: %d, hp: %d", b->dl, b->rp, b->rl, b->hp);
705 if (what & 0x04)
706 printf(" total: %d, prev_total: %d, xrun: %d", b->total, b->prev_total, b->xrun);
707 if (what & 0x08)
708 printf(" fmt: 0x%x, spd: %d", b->fmt, b->spd);
709 if (what & 0x10)
710 printf(" blksz: %d, blkcnt: %d, flags: 0x%x", b->blksz, b->blkcnt, b->flags);
711 printf(" ]\n");
712 }
713
714 /************************************************************/
715 u_int32_t
716 sndbuf_getflags(struct snd_dbuf *b)
717 {
718 return b->flags;
719 }
720
721 void
722 sndbuf_setflags(struct snd_dbuf *b, u_int32_t flags, int on)
723 {
724 b->flags &= ~flags;
725 if (on)
726 b->flags |= flags;
727 }
728
729 /**
730 * @brief Clear the shadow buffer by filling with samples equal to zero.
731 *
732 * @param b buffer to clear
733 */
734 void
735 sndbuf_clearshadow(struct snd_dbuf *b)
736 {
737 KASSERT(b != NULL, ("b is a null pointer"));
738 KASSERT(b->sl >= 0, ("illegal shadow length"));
739
740 if ((b->shadbuf != NULL) && (b->sl > 0))
741 memset(b->shadbuf, sndbuf_zerodata(b->fmt), b->sl);
742 }
743
744 #ifdef OSSV4_EXPERIMENT
745 /**
746 * @brief Return peak value from samples in buffer ready area.
747 *
748 * Peak ranges from 0-32767. If channel is monaural, most significant 16
749 * bits will be zero. For now, only expects to work with 1-2 channel
750 * buffers.
751 *
752 * @note Currently only operates with linear PCM formats.
753 *
754 * @param b buffer to analyze
755 * @param lpeak pointer to store left peak value
756 * @param rpeak pointer to store right peak value
757 */
758 void
759 sndbuf_getpeaks(struct snd_dbuf *b, int *lp, int *rp)
760 {
761 u_int32_t lpeak, rpeak;
762
763 lpeak = 0;
764 rpeak = 0;
765
766 /**
767 * @todo fill this in later
768 */
769 }
770 #endif
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