buffer.c revision 319066
1/*-
2 * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
3 * Portions Copyright (c) Ryan Beasley <ryan.beasley@gmail.com> - GSoC 2006
4 * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifdef HAVE_KERNEL_OPTION_HEADERS
30#include "opt_snd.h"
31#endif
32
33#include <dev/sound/pcm/sound.h>
34
35#include "feeder_if.h"
36
37#define SND_USE_FXDIV
38#define	SND_DECLARE_FXDIV
39#include "snd_fxdiv_gen.h"
40
41SND_DECLARE_FILE("$FreeBSD: stable/10/sys/dev/sound/pcm/buffer.c 319066 2017-05-28 10:44:43Z hselasky $");
42
43struct snd_dbuf *
44sndbuf_create(device_t dev, char *drv, char *desc, struct pcm_channel *channel)
45{
46	struct snd_dbuf *b;
47
48	b = malloc(sizeof(*b), M_DEVBUF, M_WAITOK | M_ZERO);
49	snprintf(b->name, SNDBUF_NAMELEN, "%s:%s", drv, desc);
50	b->dev = dev;
51	b->channel = channel;
52
53	return b;
54}
55
56void
57sndbuf_destroy(struct snd_dbuf *b)
58{
59	sndbuf_free(b);
60	free(b, M_DEVBUF);
61}
62
63bus_addr_t
64sndbuf_getbufaddr(struct snd_dbuf *buf)
65{
66	return (buf->buf_addr);
67}
68
69static void
70sndbuf_setmap(void *arg, bus_dma_segment_t *segs, int nseg, int error)
71{
72	struct snd_dbuf *b = (struct snd_dbuf *)arg;
73
74	if (snd_verbose > 3) {
75		device_printf(b->dev, "sndbuf_setmap %lx, %lx; ",
76		    (u_long)segs[0].ds_addr, (u_long)segs[0].ds_len);
77		printf("%p -> %lx\n", b->buf, (u_long)segs[0].ds_addr);
78	}
79	if (error == 0)
80		b->buf_addr = segs[0].ds_addr;
81	else
82		b->buf_addr = 0;
83}
84
85/*
86 * Allocate memory for DMA buffer. If the device does not use DMA transfers,
87 * the driver can call malloc(9) and sndbuf_setup() itself.
88 */
89
90int
91sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, int dmaflags,
92    unsigned int size)
93{
94	int ret;
95
96	b->dmatag = dmatag;
97	b->dmaflags = dmaflags | BUS_DMA_NOWAIT | BUS_DMA_COHERENT;
98	b->maxsize = size;
99	b->bufsize = b->maxsize;
100	b->buf_addr = 0;
101	b->flags |= SNDBUF_F_MANAGED;
102	if (bus_dmamem_alloc(b->dmatag, (void **)&b->buf, b->dmaflags,
103	    &b->dmamap)) {
104		sndbuf_free(b);
105		return (ENOMEM);
106	}
107	if (bus_dmamap_load(b->dmatag, b->dmamap, b->buf, b->maxsize,
108	    sndbuf_setmap, b, 0) != 0 || b->buf_addr == 0) {
109		sndbuf_free(b);
110		return (ENOMEM);
111	}
112
113	ret = sndbuf_resize(b, 2, b->maxsize / 2);
114	if (ret != 0)
115		sndbuf_free(b);
116
117	return (ret);
118}
119
120int
121sndbuf_setup(struct snd_dbuf *b, void *buf, unsigned int size)
122{
123	b->flags &= ~SNDBUF_F_MANAGED;
124	if (buf)
125		b->flags |= SNDBUF_F_MANAGED;
126	b->buf = buf;
127	b->maxsize = size;
128	b->bufsize = b->maxsize;
129	return sndbuf_resize(b, 2, b->maxsize / 2);
130}
131
132void
133sndbuf_free(struct snd_dbuf *b)
134{
135	if (b->tmpbuf)
136		free(b->tmpbuf, M_DEVBUF);
137
138	if (b->shadbuf)
139		free(b->shadbuf, M_DEVBUF);
140
141	if (b->buf) {
142		if (b->flags & SNDBUF_F_MANAGED) {
143			if (b->dmamap)
144				bus_dmamap_unload(b->dmatag, b->dmamap);
145			if (b->dmatag)
146				bus_dmamem_free(b->dmatag, b->buf, b->dmamap);
147		} else
148			free(b->buf, M_DEVBUF);
149	}
150
151	b->tmpbuf = NULL;
152	b->shadbuf = NULL;
153	b->buf = NULL;
154	b->sl = 0;
155	b->dmatag = NULL;
156	b->dmamap = NULL;
157}
158
159#define SNDBUF_CACHE_SHIFT	5
160
161int
162sndbuf_resize(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
163{
164	unsigned int bufsize, allocsize;
165	u_int8_t *tmpbuf;
166
167	CHN_LOCK(b->channel);
168	if (b->maxsize == 0)
169		goto out;
170	if (blkcnt == 0)
171		blkcnt = b->blkcnt;
172	if (blksz == 0)
173		blksz = b->blksz;
174	if (blkcnt < 2 || blksz < 16 || (blkcnt * blksz) > b->maxsize) {
175		CHN_UNLOCK(b->channel);
176		return EINVAL;
177	}
178	if (blkcnt == b->blkcnt && blksz == b->blksz)
179		goto out;
180
181	bufsize = blkcnt * blksz;
182
183	if (bufsize > b->allocsize ||
184	    bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
185		allocsize = round_page(bufsize);
186		CHN_UNLOCK(b->channel);
187		tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
188		CHN_LOCK(b->channel);
189		if (snd_verbose > 3)
190			printf("%s(): b=%p %p -> %p [%d -> %d : %d]\n",
191			    __func__, b, b->tmpbuf, tmpbuf,
192			    b->allocsize, allocsize, bufsize);
193		if (b->tmpbuf != NULL)
194			free(b->tmpbuf, M_DEVBUF);
195		b->tmpbuf = tmpbuf;
196		b->allocsize = allocsize;
197	} else if (snd_verbose > 3)
198		printf("%s(): b=%p %d [%d] NOCHANGE\n",
199		    __func__, b, b->allocsize, b->bufsize);
200
201	b->blkcnt = blkcnt;
202	b->blksz = blksz;
203	b->bufsize = bufsize;
204
205	sndbuf_reset(b);
206out:
207	CHN_UNLOCK(b->channel);
208	return 0;
209}
210
211int
212sndbuf_remalloc(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
213{
214        unsigned int bufsize, allocsize;
215	u_int8_t *buf, *tmpbuf, *shadbuf;
216
217	if (blkcnt < 2 || blksz < 16)
218		return EINVAL;
219
220	bufsize = blksz * blkcnt;
221
222	if (bufsize > b->allocsize ||
223	    bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
224		allocsize = round_page(bufsize);
225		CHN_UNLOCK(b->channel);
226		buf = malloc(allocsize, M_DEVBUF, M_WAITOK);
227		tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
228		shadbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
229		CHN_LOCK(b->channel);
230		if (b->buf != NULL)
231			free(b->buf, M_DEVBUF);
232		b->buf = buf;
233		if (b->tmpbuf != NULL)
234			free(b->tmpbuf, M_DEVBUF);
235		b->tmpbuf = tmpbuf;
236		if (b->shadbuf != NULL)
237			free(b->shadbuf, M_DEVBUF);
238		b->shadbuf = shadbuf;
239		if (snd_verbose > 3)
240			printf("%s(): b=%p %d -> %d [%d]\n",
241			    __func__, b, b->allocsize, allocsize, bufsize);
242		b->allocsize = allocsize;
243	} else if (snd_verbose > 3)
244		printf("%s(): b=%p %d [%d] NOCHANGE\n",
245		    __func__, b, b->allocsize, b->bufsize);
246
247	b->blkcnt = blkcnt;
248	b->blksz = blksz;
249	b->bufsize = bufsize;
250	b->maxsize = bufsize;
251	b->sl = bufsize;
252
253	sndbuf_reset(b);
254
255	return 0;
256}
257
258/**
259 * @brief Zero out space in buffer free area
260 *
261 * This function clears a chunk of @c length bytes in the buffer free area
262 * (i.e., where the next write will be placed).
263 *
264 * @param b		buffer context
265 * @param length	number of bytes to blank
266 */
267void
268sndbuf_clear(struct snd_dbuf *b, unsigned int length)
269{
270	int i;
271	u_char data, *p;
272
273	if (length == 0)
274		return;
275	if (length > b->bufsize)
276		length = b->bufsize;
277
278	data = sndbuf_zerodata(b->fmt);
279
280	i = sndbuf_getfreeptr(b);
281	p = sndbuf_getbuf(b);
282	while (length > 0) {
283		p[i] = data;
284		length--;
285		i++;
286		if (i >= b->bufsize)
287			i = 0;
288	}
289}
290
291/**
292 * @brief Zap buffer contents, resetting "ready area" fields
293 *
294 * @param b	buffer context
295 */
296void
297sndbuf_fillsilence(struct snd_dbuf *b)
298{
299	if (b->bufsize > 0)
300		memset(sndbuf_getbuf(b), sndbuf_zerodata(b->fmt), b->bufsize);
301	b->rp = 0;
302	b->rl = b->bufsize;
303}
304
305void
306sndbuf_fillsilence_rl(struct snd_dbuf *b, u_int rl)
307{
308	if (b->bufsize > 0)
309		memset(sndbuf_getbuf(b), sndbuf_zerodata(b->fmt), b->bufsize);
310	b->rp = 0;
311	b->rl = min(b->bufsize, rl);
312}
313
314/**
315 * @brief Reset buffer w/o flushing statistics
316 *
317 * This function just zeroes out buffer contents and sets the "ready length"
318 * to zero.  This was originally to facilitate minimal playback interruption
319 * (i.e., dropped samples) in SNDCTL_DSP_SILENCE/SKIP ioctls.
320 *
321 * @param b	buffer context
322 */
323void
324sndbuf_softreset(struct snd_dbuf *b)
325{
326	b->rl = 0;
327	if (b->buf && b->bufsize > 0)
328		sndbuf_clear(b, b->bufsize);
329}
330
331void
332sndbuf_reset(struct snd_dbuf *b)
333{
334	b->hp = 0;
335	b->rp = 0;
336	b->rl = 0;
337	b->dl = 0;
338	b->prev_total = 0;
339	b->total = 0;
340	b->xrun = 0;
341	if (b->buf && b->bufsize > 0)
342		sndbuf_clear(b, b->bufsize);
343	sndbuf_clearshadow(b);
344}
345
346u_int32_t
347sndbuf_getfmt(struct snd_dbuf *b)
348{
349	return b->fmt;
350}
351
352int
353sndbuf_setfmt(struct snd_dbuf *b, u_int32_t fmt)
354{
355	b->fmt = fmt;
356	b->bps = AFMT_BPS(b->fmt);
357	b->align = AFMT_ALIGN(b->fmt);
358#if 0
359	b->bps = AFMT_CHANNEL(b->fmt);
360	if (b->fmt & AFMT_16BIT)
361		b->bps <<= 1;
362	else if (b->fmt & AFMT_24BIT)
363		b->bps *= 3;
364	else if (b->fmt & AFMT_32BIT)
365		b->bps <<= 2;
366#endif
367	return 0;
368}
369
370unsigned int
371sndbuf_getspd(struct snd_dbuf *b)
372{
373	return b->spd;
374}
375
376void
377sndbuf_setspd(struct snd_dbuf *b, unsigned int spd)
378{
379	b->spd = spd;
380}
381
382unsigned int
383sndbuf_getalign(struct snd_dbuf *b)
384{
385	return (b->align);
386}
387
388unsigned int
389sndbuf_getblkcnt(struct snd_dbuf *b)
390{
391	return b->blkcnt;
392}
393
394void
395sndbuf_setblkcnt(struct snd_dbuf *b, unsigned int blkcnt)
396{
397	b->blkcnt = blkcnt;
398}
399
400unsigned int
401sndbuf_getblksz(struct snd_dbuf *b)
402{
403	return b->blksz;
404}
405
406void
407sndbuf_setblksz(struct snd_dbuf *b, unsigned int blksz)
408{
409	b->blksz = blksz;
410}
411
412unsigned int
413sndbuf_getbps(struct snd_dbuf *b)
414{
415	return b->bps;
416}
417
418void *
419sndbuf_getbuf(struct snd_dbuf *b)
420{
421	return b->buf;
422}
423
424void *
425sndbuf_getbufofs(struct snd_dbuf *b, unsigned int ofs)
426{
427	KASSERT(ofs < b->bufsize, ("%s: ofs invalid %d", __func__, ofs));
428
429	return b->buf + ofs;
430}
431
432unsigned int
433sndbuf_getsize(struct snd_dbuf *b)
434{
435	return b->bufsize;
436}
437
438unsigned int
439sndbuf_getmaxsize(struct snd_dbuf *b)
440{
441	return b->maxsize;
442}
443
444unsigned int
445sndbuf_getallocsize(struct snd_dbuf *b)
446{
447	return b->allocsize;
448}
449
450unsigned int
451sndbuf_runsz(struct snd_dbuf *b)
452{
453	return b->dl;
454}
455
456void
457sndbuf_setrun(struct snd_dbuf *b, int go)
458{
459	b->dl = go? b->blksz : 0;
460}
461
462struct selinfo *
463sndbuf_getsel(struct snd_dbuf *b)
464{
465	return &b->sel;
466}
467
468/************************************************************/
469unsigned int
470sndbuf_getxrun(struct snd_dbuf *b)
471{
472	SNDBUF_LOCKASSERT(b);
473
474	return b->xrun;
475}
476
477void
478sndbuf_setxrun(struct snd_dbuf *b, unsigned int xrun)
479{
480	SNDBUF_LOCKASSERT(b);
481
482	b->xrun = xrun;
483}
484
485unsigned int
486sndbuf_gethwptr(struct snd_dbuf *b)
487{
488	SNDBUF_LOCKASSERT(b);
489
490	return b->hp;
491}
492
493void
494sndbuf_sethwptr(struct snd_dbuf *b, unsigned int ptr)
495{
496	SNDBUF_LOCKASSERT(b);
497
498	b->hp = ptr;
499}
500
501unsigned int
502sndbuf_getready(struct snd_dbuf *b)
503{
504	SNDBUF_LOCKASSERT(b);
505	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
506
507	return b->rl;
508}
509
510unsigned int
511sndbuf_getreadyptr(struct snd_dbuf *b)
512{
513	SNDBUF_LOCKASSERT(b);
514	KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
515
516	return b->rp;
517}
518
519unsigned int
520sndbuf_getfree(struct snd_dbuf *b)
521{
522	SNDBUF_LOCKASSERT(b);
523	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
524
525	return b->bufsize - b->rl;
526}
527
528unsigned int
529sndbuf_getfreeptr(struct snd_dbuf *b)
530{
531	SNDBUF_LOCKASSERT(b);
532	KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
533	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
534
535	return (b->rp + b->rl) % b->bufsize;
536}
537
538u_int64_t
539sndbuf_getblocks(struct snd_dbuf *b)
540{
541	SNDBUF_LOCKASSERT(b);
542
543	return b->total / b->blksz;
544}
545
546u_int64_t
547sndbuf_getprevblocks(struct snd_dbuf *b)
548{
549	SNDBUF_LOCKASSERT(b);
550
551	return b->prev_total / b->blksz;
552}
553
554u_int64_t
555sndbuf_gettotal(struct snd_dbuf *b)
556{
557	SNDBUF_LOCKASSERT(b);
558
559	return b->total;
560}
561
562u_int64_t
563sndbuf_getprevtotal(struct snd_dbuf *b)
564{
565	SNDBUF_LOCKASSERT(b);
566
567	return b->prev_total;
568}
569
570void
571sndbuf_updateprevtotal(struct snd_dbuf *b)
572{
573	SNDBUF_LOCKASSERT(b);
574
575	b->prev_total = b->total;
576}
577
578unsigned int
579sndbuf_xbytes(unsigned int v, struct snd_dbuf *from, struct snd_dbuf *to)
580{
581	if (from == NULL || to == NULL || v == 0)
582		return 0;
583
584	return snd_xbytes(v, sndbuf_getalign(from) * sndbuf_getspd(from),
585	    sndbuf_getalign(to) * sndbuf_getspd(to));
586}
587
588u_int8_t
589sndbuf_zerodata(u_int32_t fmt)
590{
591	if (fmt & (AFMT_SIGNED | AFMT_PASSTHROUGH))
592		return (0x00);
593	else if (fmt & AFMT_MU_LAW)
594		return (0x7f);
595	else if (fmt & AFMT_A_LAW)
596		return (0x55);
597	return (0x80);
598}
599
600/************************************************************/
601
602/**
603 * @brief Acquire buffer space to extend ready area
604 *
605 * This function extends the ready area length by @c count bytes, and may
606 * optionally copy samples from another location stored in @c from.  The
607 * counter @c snd_dbuf::total is also incremented by @c count bytes.
608 *
609 * @param b	audio buffer
610 * @param from	sample source (optional)
611 * @param count	number of bytes to acquire
612 *
613 * @retval 0	Unconditional
614 */
615int
616sndbuf_acquire(struct snd_dbuf *b, u_int8_t *from, unsigned int count)
617{
618	int l;
619
620	KASSERT(count <= sndbuf_getfree(b), ("%s: count %d > free %d", __func__, count, sndbuf_getfree(b)));
621	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
622	b->total += count;
623	if (from != NULL) {
624		while (count > 0) {
625			l = min(count, sndbuf_getsize(b) - sndbuf_getfreeptr(b));
626			bcopy(from, sndbuf_getbufofs(b, sndbuf_getfreeptr(b)), l);
627			from += l;
628			b->rl += l;
629			count -= l;
630		}
631	} else
632		b->rl += count;
633	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
634
635	return 0;
636}
637
638/**
639 * @brief Dispose samples from channel buffer, increasing size of ready area
640 *
641 * This function discards samples from the supplied buffer by advancing the
642 * ready area start pointer and decrementing the ready area length.  If
643 * @c to is not NULL, then the discard samples will be copied to the location
644 * it points to.
645 *
646 * @param b	PCM channel sound buffer
647 * @param to	destination buffer (optional)
648 * @param count	number of bytes to discard
649 *
650 * @returns 0 unconditionally
651 */
652int
653sndbuf_dispose(struct snd_dbuf *b, u_int8_t *to, unsigned int count)
654{
655	int l;
656
657	KASSERT(count <= sndbuf_getready(b), ("%s: count %d > ready %d", __func__, count, sndbuf_getready(b)));
658	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
659	if (to != NULL) {
660		while (count > 0) {
661			l = min(count, sndbuf_getsize(b) - sndbuf_getreadyptr(b));
662			bcopy(sndbuf_getbufofs(b, sndbuf_getreadyptr(b)), to, l);
663			to += l;
664			b->rl -= l;
665			b->rp = (b->rp + l) % b->bufsize;
666			count -= l;
667		}
668	} else {
669		b->rl -= count;
670		b->rp = (b->rp + count) % b->bufsize;
671	}
672	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
673
674	return 0;
675}
676
677#ifdef SND_DIAGNOSTIC
678static uint32_t snd_feeder_maxfeed = 0;
679SYSCTL_UINT(_hw_snd, OID_AUTO, feeder_maxfeed, CTLFLAG_RD,
680    &snd_feeder_maxfeed, 0, "maximum feeder count request");
681
682static uint32_t snd_feeder_maxcycle = 0;
683SYSCTL_UINT(_hw_snd, OID_AUTO, feeder_maxcycle, CTLFLAG_RD,
684    &snd_feeder_maxcycle, 0, "maximum feeder cycle");
685#endif
686
687/* count is number of bytes we want added to destination buffer */
688int
689sndbuf_feed(struct snd_dbuf *from, struct snd_dbuf *to, struct pcm_channel *channel, struct pcm_feeder *feeder, unsigned int count)
690{
691	unsigned int cnt, maxfeed;
692#ifdef SND_DIAGNOSTIC
693	unsigned int cycle;
694
695	if (count > snd_feeder_maxfeed)
696		snd_feeder_maxfeed = count;
697
698	cycle = 0;
699#endif
700
701	KASSERT(count > 0, ("can't feed 0 bytes"));
702
703	if (sndbuf_getfree(to) < count)
704		return (EINVAL);
705
706	maxfeed = SND_FXROUND(SND_FXDIV_MAX, sndbuf_getalign(to));
707
708	do {
709		cnt = FEEDER_FEED(feeder, channel, to->tmpbuf,
710		    min(count, maxfeed), from);
711		if (cnt == 0)
712			break;
713		sndbuf_acquire(to, to->tmpbuf, cnt);
714		count -= cnt;
715#ifdef SND_DIAGNOSTIC
716		cycle++;
717#endif
718	} while (count != 0);
719
720#ifdef SND_DIAGNOSTIC
721	if (cycle > snd_feeder_maxcycle)
722		snd_feeder_maxcycle = cycle;
723#endif
724
725	return (0);
726}
727
728/************************************************************/
729
730void
731sndbuf_dump(struct snd_dbuf *b, char *s, u_int32_t what)
732{
733	printf("%s: [", s);
734	if (what & 0x01)
735		printf(" bufsize: %d, maxsize: %d", b->bufsize, b->maxsize);
736	if (what & 0x02)
737		printf(" dl: %d, rp: %d, rl: %d, hp: %d", b->dl, b->rp, b->rl, b->hp);
738	if (what & 0x04)
739		printf(" total: %ju, prev_total: %ju, xrun: %d", (uintmax_t)b->total, (uintmax_t)b->prev_total, b->xrun);
740   	if (what & 0x08)
741		printf(" fmt: 0x%x, spd: %d", b->fmt, b->spd);
742	if (what & 0x10)
743		printf(" blksz: %d, blkcnt: %d, flags: 0x%x", b->blksz, b->blkcnt, b->flags);
744	printf(" ]\n");
745}
746
747/************************************************************/
748u_int32_t
749sndbuf_getflags(struct snd_dbuf *b)
750{
751	return b->flags;
752}
753
754void
755sndbuf_setflags(struct snd_dbuf *b, u_int32_t flags, int on)
756{
757	b->flags &= ~flags;
758	if (on)
759		b->flags |= flags;
760}
761
762/**
763 * @brief Clear the shadow buffer by filling with samples equal to zero.
764 *
765 * @param b buffer to clear
766 */
767void
768sndbuf_clearshadow(struct snd_dbuf *b)
769{
770	KASSERT(b != NULL, ("b is a null pointer"));
771	KASSERT(b->sl >= 0, ("illegal shadow length"));
772
773	if ((b->shadbuf != NULL) && (b->sl > 0))
774		memset(b->shadbuf, sndbuf_zerodata(b->fmt), b->sl);
775}
776
777#ifdef OSSV4_EXPERIMENT
778/**
779 * @brief Return peak value from samples in buffer ready area.
780 *
781 * Peak ranges from 0-32767.  If channel is monaural, most significant 16
782 * bits will be zero.  For now, only expects to work with 1-2 channel
783 * buffers.
784 *
785 * @note  Currently only operates with linear PCM formats.
786 *
787 * @param b buffer to analyze
788 * @param lpeak pointer to store left peak value
789 * @param rpeak pointer to store right peak value
790 */
791void
792sndbuf_getpeaks(struct snd_dbuf *b, int *lp, int *rp)
793{
794	u_int32_t lpeak, rpeak;
795
796	lpeak = 0;
797	rpeak = 0;
798
799	/**
800	 * @todo fill this in later
801	 */
802}
803#endif
804