xref: /freebsd/sys/dev/sound/pcm/buffer.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2005-2009 Ariff Abdullah <ariff@FreeBSD.org>
5  * Portions Copyright (c) Ryan Beasley <ryan.beasley@gmail.com> - GSoC 2006
6  * Copyright (c) 1999 Cameron Grant <cg@FreeBSD.org>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #ifdef HAVE_KERNEL_OPTION_HEADERS
32 #include "opt_snd.h"
33 #endif
34 
35 #include <dev/sound/pcm/sound.h>
36 
37 #include "feeder_if.h"
38 
39 #define SND_USE_FXDIV
40 #define	SND_DECLARE_FXDIV
41 #include "snd_fxdiv_gen.h"
42 
43 SND_DECLARE_FILE("$FreeBSD$");
44 
45 struct snd_dbuf *
46 sndbuf_create(device_t dev, char *drv, char *desc, struct pcm_channel *channel)
47 {
48 	struct snd_dbuf *b;
49 
50 	b = malloc(sizeof(*b), M_DEVBUF, M_WAITOK | M_ZERO);
51 	snprintf(b->name, SNDBUF_NAMELEN, "%s:%s", drv, desc);
52 	b->dev = dev;
53 	b->channel = channel;
54 
55 	return b;
56 }
57 
58 void
59 sndbuf_destroy(struct snd_dbuf *b)
60 {
61 	sndbuf_free(b);
62 	free(b, M_DEVBUF);
63 }
64 
65 bus_addr_t
66 sndbuf_getbufaddr(struct snd_dbuf *buf)
67 {
68 	return (buf->buf_addr);
69 }
70 
71 static void
72 sndbuf_setmap(void *arg, bus_dma_segment_t *segs, int nseg, int error)
73 {
74 	struct snd_dbuf *b = (struct snd_dbuf *)arg;
75 
76 	if (snd_verbose > 3) {
77 		device_printf(b->dev, "sndbuf_setmap %lx, %lx; ",
78 		    (u_long)segs[0].ds_addr, (u_long)segs[0].ds_len);
79 		printf("%p -> %lx\n", b->buf, (u_long)segs[0].ds_addr);
80 	}
81 	if (error == 0)
82 		b->buf_addr = segs[0].ds_addr;
83 	else
84 		b->buf_addr = 0;
85 }
86 
87 /*
88  * Allocate memory for DMA buffer. If the device does not use DMA transfers,
89  * the driver can call malloc(9) and sndbuf_setup() itself.
90  */
91 
92 int
93 sndbuf_alloc(struct snd_dbuf *b, bus_dma_tag_t dmatag, int dmaflags,
94     unsigned int size)
95 {
96 	int ret;
97 
98 	b->dmatag = dmatag;
99 	b->dmaflags = dmaflags | BUS_DMA_NOWAIT | BUS_DMA_COHERENT;
100 	b->maxsize = size;
101 	b->bufsize = b->maxsize;
102 	b->buf_addr = 0;
103 	b->flags |= SNDBUF_F_MANAGED;
104 	if (bus_dmamem_alloc(b->dmatag, (void **)&b->buf, b->dmaflags,
105 	    &b->dmamap)) {
106 		sndbuf_free(b);
107 		return (ENOMEM);
108 	}
109 	if (bus_dmamap_load(b->dmatag, b->dmamap, b->buf, b->maxsize,
110 	    sndbuf_setmap, b, 0) != 0 || b->buf_addr == 0) {
111 		sndbuf_free(b);
112 		return (ENOMEM);
113 	}
114 
115 	ret = sndbuf_resize(b, 2, b->maxsize / 2);
116 	if (ret != 0)
117 		sndbuf_free(b);
118 
119 	return (ret);
120 }
121 
122 int
123 sndbuf_setup(struct snd_dbuf *b, void *buf, unsigned int size)
124 {
125 	b->flags &= ~SNDBUF_F_MANAGED;
126 	if (buf)
127 		b->flags |= SNDBUF_F_MANAGED;
128 	b->buf = buf;
129 	b->maxsize = size;
130 	b->bufsize = b->maxsize;
131 	return sndbuf_resize(b, 2, b->maxsize / 2);
132 }
133 
134 void
135 sndbuf_free(struct snd_dbuf *b)
136 {
137 	if (b->tmpbuf)
138 		free(b->tmpbuf, M_DEVBUF);
139 
140 	if (b->shadbuf)
141 		free(b->shadbuf, M_DEVBUF);
142 
143 	if (b->buf) {
144 		if (b->flags & SNDBUF_F_MANAGED) {
145 			if (b->buf_addr)
146 				bus_dmamap_unload(b->dmatag, b->dmamap);
147 			if (b->dmatag)
148 				bus_dmamem_free(b->dmatag, b->buf, b->dmamap);
149 		} else
150 			free(b->buf, M_DEVBUF);
151 	}
152 
153 	b->tmpbuf = NULL;
154 	b->shadbuf = NULL;
155 	b->buf = NULL;
156 	b->sl = 0;
157 	b->dmatag = NULL;
158 	b->dmamap = NULL;
159 }
160 
161 #define SNDBUF_CACHE_SHIFT	5
162 
163 int
164 sndbuf_resize(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
165 {
166 	unsigned int bufsize, allocsize;
167 	u_int8_t *tmpbuf;
168 
169 	CHN_LOCK(b->channel);
170 	if (b->maxsize == 0)
171 		goto out;
172 	if (blkcnt == 0)
173 		blkcnt = b->blkcnt;
174 	if (blksz == 0)
175 		blksz = b->blksz;
176 	if (blkcnt < 2 || blksz < 16 || (blkcnt * blksz) > b->maxsize) {
177 		CHN_UNLOCK(b->channel);
178 		return EINVAL;
179 	}
180 	if (blkcnt == b->blkcnt && blksz == b->blksz)
181 		goto out;
182 
183 	bufsize = blkcnt * blksz;
184 
185 	if (bufsize > b->allocsize ||
186 	    bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
187 		allocsize = round_page(bufsize);
188 		CHN_UNLOCK(b->channel);
189 		tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
190 		CHN_LOCK(b->channel);
191 		if (snd_verbose > 3)
192 			printf("%s(): b=%p %p -> %p [%d -> %d : %d]\n",
193 			    __func__, b, b->tmpbuf, tmpbuf,
194 			    b->allocsize, allocsize, bufsize);
195 		if (b->tmpbuf != NULL)
196 			free(b->tmpbuf, M_DEVBUF);
197 		b->tmpbuf = tmpbuf;
198 		b->allocsize = allocsize;
199 	} else if (snd_verbose > 3)
200 		printf("%s(): b=%p %d [%d] NOCHANGE\n",
201 		    __func__, b, b->allocsize, b->bufsize);
202 
203 	b->blkcnt = blkcnt;
204 	b->blksz = blksz;
205 	b->bufsize = bufsize;
206 
207 	sndbuf_reset(b);
208 out:
209 	CHN_UNLOCK(b->channel);
210 	return 0;
211 }
212 
213 int
214 sndbuf_remalloc(struct snd_dbuf *b, unsigned int blkcnt, unsigned int blksz)
215 {
216         unsigned int bufsize, allocsize;
217 	u_int8_t *buf, *tmpbuf, *shadbuf;
218 
219 	if (blkcnt < 2 || blksz < 16)
220 		return EINVAL;
221 
222 	bufsize = blksz * blkcnt;
223 
224 	if (bufsize > b->allocsize ||
225 	    bufsize < (b->allocsize >> SNDBUF_CACHE_SHIFT)) {
226 		allocsize = round_page(bufsize);
227 		CHN_UNLOCK(b->channel);
228 		buf = malloc(allocsize, M_DEVBUF, M_WAITOK);
229 		tmpbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
230 		shadbuf = malloc(allocsize, M_DEVBUF, M_WAITOK);
231 		CHN_LOCK(b->channel);
232 		if (b->buf != NULL)
233 			free(b->buf, M_DEVBUF);
234 		b->buf = buf;
235 		if (b->tmpbuf != NULL)
236 			free(b->tmpbuf, M_DEVBUF);
237 		b->tmpbuf = tmpbuf;
238 		if (b->shadbuf != NULL)
239 			free(b->shadbuf, M_DEVBUF);
240 		b->shadbuf = shadbuf;
241 		if (snd_verbose > 3)
242 			printf("%s(): b=%p %d -> %d [%d]\n",
243 			    __func__, b, b->allocsize, allocsize, bufsize);
244 		b->allocsize = allocsize;
245 	} else if (snd_verbose > 3)
246 		printf("%s(): b=%p %d [%d] NOCHANGE\n",
247 		    __func__, b, b->allocsize, b->bufsize);
248 
249 	b->blkcnt = blkcnt;
250 	b->blksz = blksz;
251 	b->bufsize = bufsize;
252 	b->maxsize = bufsize;
253 	b->sl = bufsize;
254 
255 	sndbuf_reset(b);
256 
257 	return 0;
258 }
259 
260 /**
261  * @brief Zero out space in buffer free area
262  *
263  * This function clears a chunk of @c length bytes in the buffer free area
264  * (i.e., where the next write will be placed).
265  *
266  * @param b		buffer context
267  * @param length	number of bytes to blank
268  */
269 void
270 sndbuf_clear(struct snd_dbuf *b, unsigned int length)
271 {
272 	int i;
273 	u_char data, *p;
274 
275 	if (length == 0)
276 		return;
277 	if (length > b->bufsize)
278 		length = b->bufsize;
279 
280 	data = sndbuf_zerodata(b->fmt);
281 
282 	i = sndbuf_getfreeptr(b);
283 	p = sndbuf_getbuf(b);
284 	while (length > 0) {
285 		p[i] = data;
286 		length--;
287 		i++;
288 		if (i >= b->bufsize)
289 			i = 0;
290 	}
291 }
292 
293 /**
294  * @brief Zap buffer contents, resetting "ready area" fields
295  *
296  * @param b	buffer context
297  */
298 void
299 sndbuf_fillsilence(struct snd_dbuf *b)
300 {
301 	if (b->bufsize > 0)
302 		memset(sndbuf_getbuf(b), sndbuf_zerodata(b->fmt), b->bufsize);
303 	b->rp = 0;
304 	b->rl = b->bufsize;
305 }
306 
307 void
308 sndbuf_fillsilence_rl(struct snd_dbuf *b, u_int rl)
309 {
310 	if (b->bufsize > 0)
311 		memset(sndbuf_getbuf(b), sndbuf_zerodata(b->fmt), b->bufsize);
312 	b->rp = 0;
313 	b->rl = min(b->bufsize, rl);
314 }
315 
316 /**
317  * @brief Reset buffer w/o flushing statistics
318  *
319  * This function just zeroes out buffer contents and sets the "ready length"
320  * to zero.  This was originally to facilitate minimal playback interruption
321  * (i.e., dropped samples) in SNDCTL_DSP_SILENCE/SKIP ioctls.
322  *
323  * @param b	buffer context
324  */
325 void
326 sndbuf_softreset(struct snd_dbuf *b)
327 {
328 	b->rl = 0;
329 	if (b->buf && b->bufsize > 0)
330 		sndbuf_clear(b, b->bufsize);
331 }
332 
333 void
334 sndbuf_reset(struct snd_dbuf *b)
335 {
336 	b->hp = 0;
337 	b->rp = 0;
338 	b->rl = 0;
339 	b->dl = 0;
340 	b->prev_total = 0;
341 	b->total = 0;
342 	b->xrun = 0;
343 	if (b->buf && b->bufsize > 0)
344 		sndbuf_clear(b, b->bufsize);
345 	sndbuf_clearshadow(b);
346 }
347 
348 u_int32_t
349 sndbuf_getfmt(struct snd_dbuf *b)
350 {
351 	return b->fmt;
352 }
353 
354 int
355 sndbuf_setfmt(struct snd_dbuf *b, u_int32_t fmt)
356 {
357 	b->fmt = fmt;
358 	b->bps = AFMT_BPS(b->fmt);
359 	b->align = AFMT_ALIGN(b->fmt);
360 #if 0
361 	b->bps = AFMT_CHANNEL(b->fmt);
362 	if (b->fmt & AFMT_16BIT)
363 		b->bps <<= 1;
364 	else if (b->fmt & AFMT_24BIT)
365 		b->bps *= 3;
366 	else if (b->fmt & AFMT_32BIT)
367 		b->bps <<= 2;
368 #endif
369 	return 0;
370 }
371 
372 unsigned int
373 sndbuf_getspd(struct snd_dbuf *b)
374 {
375 	return b->spd;
376 }
377 
378 void
379 sndbuf_setspd(struct snd_dbuf *b, unsigned int spd)
380 {
381 	b->spd = spd;
382 }
383 
384 unsigned int
385 sndbuf_getalign(struct snd_dbuf *b)
386 {
387 	return (b->align);
388 }
389 
390 unsigned int
391 sndbuf_getblkcnt(struct snd_dbuf *b)
392 {
393 	return b->blkcnt;
394 }
395 
396 void
397 sndbuf_setblkcnt(struct snd_dbuf *b, unsigned int blkcnt)
398 {
399 	b->blkcnt = blkcnt;
400 }
401 
402 unsigned int
403 sndbuf_getblksz(struct snd_dbuf *b)
404 {
405 	return b->blksz;
406 }
407 
408 void
409 sndbuf_setblksz(struct snd_dbuf *b, unsigned int blksz)
410 {
411 	b->blksz = blksz;
412 }
413 
414 unsigned int
415 sndbuf_getbps(struct snd_dbuf *b)
416 {
417 	return b->bps;
418 }
419 
420 void *
421 sndbuf_getbuf(struct snd_dbuf *b)
422 {
423 	return b->buf;
424 }
425 
426 void *
427 sndbuf_getbufofs(struct snd_dbuf *b, unsigned int ofs)
428 {
429 	KASSERT(ofs < b->bufsize, ("%s: ofs invalid %d", __func__, ofs));
430 
431 	return b->buf + ofs;
432 }
433 
434 unsigned int
435 sndbuf_getsize(struct snd_dbuf *b)
436 {
437 	return b->bufsize;
438 }
439 
440 unsigned int
441 sndbuf_getmaxsize(struct snd_dbuf *b)
442 {
443 	return b->maxsize;
444 }
445 
446 unsigned int
447 sndbuf_getallocsize(struct snd_dbuf *b)
448 {
449 	return b->allocsize;
450 }
451 
452 unsigned int
453 sndbuf_runsz(struct snd_dbuf *b)
454 {
455 	return b->dl;
456 }
457 
458 void
459 sndbuf_setrun(struct snd_dbuf *b, int go)
460 {
461 	b->dl = go? b->blksz : 0;
462 }
463 
464 struct selinfo *
465 sndbuf_getsel(struct snd_dbuf *b)
466 {
467 	return &b->sel;
468 }
469 
470 /************************************************************/
471 unsigned int
472 sndbuf_getxrun(struct snd_dbuf *b)
473 {
474 	SNDBUF_LOCKASSERT(b);
475 
476 	return b->xrun;
477 }
478 
479 void
480 sndbuf_setxrun(struct snd_dbuf *b, unsigned int xrun)
481 {
482 	SNDBUF_LOCKASSERT(b);
483 
484 	b->xrun = xrun;
485 }
486 
487 unsigned int
488 sndbuf_gethwptr(struct snd_dbuf *b)
489 {
490 	SNDBUF_LOCKASSERT(b);
491 
492 	return b->hp;
493 }
494 
495 void
496 sndbuf_sethwptr(struct snd_dbuf *b, unsigned int ptr)
497 {
498 	SNDBUF_LOCKASSERT(b);
499 
500 	b->hp = ptr;
501 }
502 
503 unsigned int
504 sndbuf_getready(struct snd_dbuf *b)
505 {
506 	SNDBUF_LOCKASSERT(b);
507 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
508 
509 	return b->rl;
510 }
511 
512 unsigned int
513 sndbuf_getreadyptr(struct snd_dbuf *b)
514 {
515 	SNDBUF_LOCKASSERT(b);
516 	KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
517 
518 	return b->rp;
519 }
520 
521 unsigned int
522 sndbuf_getfree(struct snd_dbuf *b)
523 {
524 	SNDBUF_LOCKASSERT(b);
525 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
526 
527 	return b->bufsize - b->rl;
528 }
529 
530 unsigned int
531 sndbuf_getfreeptr(struct snd_dbuf *b)
532 {
533 	SNDBUF_LOCKASSERT(b);
534 	KASSERT((b->rp >= 0) && (b->rp <= b->bufsize), ("%s: b->rp invalid %d", __func__, b->rp));
535 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
536 
537 	return (b->rp + b->rl) % b->bufsize;
538 }
539 
540 u_int64_t
541 sndbuf_getblocks(struct snd_dbuf *b)
542 {
543 	SNDBUF_LOCKASSERT(b);
544 
545 	return b->total / b->blksz;
546 }
547 
548 u_int64_t
549 sndbuf_getprevblocks(struct snd_dbuf *b)
550 {
551 	SNDBUF_LOCKASSERT(b);
552 
553 	return b->prev_total / b->blksz;
554 }
555 
556 u_int64_t
557 sndbuf_gettotal(struct snd_dbuf *b)
558 {
559 	SNDBUF_LOCKASSERT(b);
560 
561 	return b->total;
562 }
563 
564 u_int64_t
565 sndbuf_getprevtotal(struct snd_dbuf *b)
566 {
567 	SNDBUF_LOCKASSERT(b);
568 
569 	return b->prev_total;
570 }
571 
572 void
573 sndbuf_updateprevtotal(struct snd_dbuf *b)
574 {
575 	SNDBUF_LOCKASSERT(b);
576 
577 	b->prev_total = b->total;
578 }
579 
580 unsigned int
581 sndbuf_xbytes(unsigned int v, struct snd_dbuf *from, struct snd_dbuf *to)
582 {
583 	if (from == NULL || to == NULL || v == 0)
584 		return 0;
585 
586 	return snd_xbytes(v, sndbuf_getalign(from) * sndbuf_getspd(from),
587 	    sndbuf_getalign(to) * sndbuf_getspd(to));
588 }
589 
590 u_int8_t
591 sndbuf_zerodata(u_int32_t fmt)
592 {
593 	if (fmt & (AFMT_SIGNED | AFMT_PASSTHROUGH))
594 		return (0x00);
595 	else if (fmt & AFMT_MU_LAW)
596 		return (0x7f);
597 	else if (fmt & AFMT_A_LAW)
598 		return (0x55);
599 	return (0x80);
600 }
601 
602 /************************************************************/
603 
604 /**
605  * @brief Acquire buffer space to extend ready area
606  *
607  * This function extends the ready area length by @c count bytes, and may
608  * optionally copy samples from another location stored in @c from.  The
609  * counter @c snd_dbuf::total is also incremented by @c count bytes.
610  *
611  * @param b	audio buffer
612  * @param from	sample source (optional)
613  * @param count	number of bytes to acquire
614  *
615  * @retval 0	Unconditional
616  */
617 int
618 sndbuf_acquire(struct snd_dbuf *b, u_int8_t *from, unsigned int count)
619 {
620 	int l;
621 
622 	KASSERT(count <= sndbuf_getfree(b), ("%s: count %d > free %d", __func__, count, sndbuf_getfree(b)));
623 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
624 	b->total += count;
625 	if (from != NULL) {
626 		while (count > 0) {
627 			l = min(count, sndbuf_getsize(b) - sndbuf_getfreeptr(b));
628 			bcopy(from, sndbuf_getbufofs(b, sndbuf_getfreeptr(b)), l);
629 			from += l;
630 			b->rl += l;
631 			count -= l;
632 		}
633 	} else
634 		b->rl += count;
635 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
636 
637 	return 0;
638 }
639 
640 /**
641  * @brief Dispose samples from channel buffer, increasing size of ready area
642  *
643  * This function discards samples from the supplied buffer by advancing the
644  * ready area start pointer and decrementing the ready area length.  If
645  * @c to is not NULL, then the discard samples will be copied to the location
646  * it points to.
647  *
648  * @param b	PCM channel sound buffer
649  * @param to	destination buffer (optional)
650  * @param count	number of bytes to discard
651  *
652  * @returns 0 unconditionally
653  */
654 int
655 sndbuf_dispose(struct snd_dbuf *b, u_int8_t *to, unsigned int count)
656 {
657 	int l;
658 
659 	KASSERT(count <= sndbuf_getready(b), ("%s: count %d > ready %d", __func__, count, sndbuf_getready(b)));
660 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d", __func__, b->rl));
661 	if (to != NULL) {
662 		while (count > 0) {
663 			l = min(count, sndbuf_getsize(b) - sndbuf_getreadyptr(b));
664 			bcopy(sndbuf_getbufofs(b, sndbuf_getreadyptr(b)), to, l);
665 			to += l;
666 			b->rl -= l;
667 			b->rp = (b->rp + l) % b->bufsize;
668 			count -= l;
669 		}
670 	} else {
671 		b->rl -= count;
672 		b->rp = (b->rp + count) % b->bufsize;
673 	}
674 	KASSERT((b->rl >= 0) && (b->rl <= b->bufsize), ("%s: b->rl invalid %d, count %d", __func__, b->rl, count));
675 
676 	return 0;
677 }
678 
679 #ifdef SND_DIAGNOSTIC
680 static uint32_t snd_feeder_maxfeed = 0;
681 SYSCTL_UINT(_hw_snd, OID_AUTO, feeder_maxfeed, CTLFLAG_RD,
682     &snd_feeder_maxfeed, 0, "maximum feeder count request");
683 
684 static uint32_t snd_feeder_maxcycle = 0;
685 SYSCTL_UINT(_hw_snd, OID_AUTO, feeder_maxcycle, CTLFLAG_RD,
686     &snd_feeder_maxcycle, 0, "maximum feeder cycle");
687 #endif
688 
689 /* count is number of bytes we want added to destination buffer */
690 int
691 sndbuf_feed(struct snd_dbuf *from, struct snd_dbuf *to, struct pcm_channel *channel, struct pcm_feeder *feeder, unsigned int count)
692 {
693 	unsigned int cnt, maxfeed;
694 #ifdef SND_DIAGNOSTIC
695 	unsigned int cycle;
696 
697 	if (count > snd_feeder_maxfeed)
698 		snd_feeder_maxfeed = count;
699 
700 	cycle = 0;
701 #endif
702 
703 	KASSERT(count > 0, ("can't feed 0 bytes"));
704 
705 	if (sndbuf_getfree(to) < count)
706 		return (EINVAL);
707 
708 	maxfeed = SND_FXROUND(SND_FXDIV_MAX, sndbuf_getalign(to));
709 
710 	do {
711 		cnt = FEEDER_FEED(feeder, channel, to->tmpbuf,
712 		    min(count, maxfeed), from);
713 		if (cnt == 0)
714 			break;
715 		sndbuf_acquire(to, to->tmpbuf, cnt);
716 		count -= cnt;
717 #ifdef SND_DIAGNOSTIC
718 		cycle++;
719 #endif
720 	} while (count != 0);
721 
722 #ifdef SND_DIAGNOSTIC
723 	if (cycle > snd_feeder_maxcycle)
724 		snd_feeder_maxcycle = cycle;
725 #endif
726 
727 	return (0);
728 }
729 
730 /************************************************************/
731 
732 void
733 sndbuf_dump(struct snd_dbuf *b, char *s, u_int32_t what)
734 {
735 	printf("%s: [", s);
736 	if (what & 0x01)
737 		printf(" bufsize: %d, maxsize: %d", b->bufsize, b->maxsize);
738 	if (what & 0x02)
739 		printf(" dl: %d, rp: %d, rl: %d, hp: %d", b->dl, b->rp, b->rl, b->hp);
740 	if (what & 0x04)
741 		printf(" total: %ju, prev_total: %ju, xrun: %d", (uintmax_t)b->total, (uintmax_t)b->prev_total, b->xrun);
742    	if (what & 0x08)
743 		printf(" fmt: 0x%x, spd: %d", b->fmt, b->spd);
744 	if (what & 0x10)
745 		printf(" blksz: %d, blkcnt: %d, flags: 0x%x", b->blksz, b->blkcnt, b->flags);
746 	printf(" ]\n");
747 }
748 
749 /************************************************************/
750 u_int32_t
751 sndbuf_getflags(struct snd_dbuf *b)
752 {
753 	return b->flags;
754 }
755 
756 void
757 sndbuf_setflags(struct snd_dbuf *b, u_int32_t flags, int on)
758 {
759 	b->flags &= ~flags;
760 	if (on)
761 		b->flags |= flags;
762 }
763 
764 /**
765  * @brief Clear the shadow buffer by filling with samples equal to zero.
766  *
767  * @param b buffer to clear
768  */
769 void
770 sndbuf_clearshadow(struct snd_dbuf *b)
771 {
772 	KASSERT(b != NULL, ("b is a null pointer"));
773 	KASSERT(b->sl >= 0, ("illegal shadow length"));
774 
775 	if ((b->shadbuf != NULL) && (b->sl > 0))
776 		memset(b->shadbuf, sndbuf_zerodata(b->fmt), b->sl);
777 }
778 
779 #ifdef OSSV4_EXPERIMENT
780 /**
781  * @brief Return peak value from samples in buffer ready area.
782  *
783  * Peak ranges from 0-32767.  If channel is monaural, most significant 16
784  * bits will be zero.  For now, only expects to work with 1-2 channel
785  * buffers.
786  *
787  * @note  Currently only operates with linear PCM formats.
788  *
789  * @param b buffer to analyze
790  * @param lpeak pointer to store left peak value
791  * @param rpeak pointer to store right peak value
792  */
793 void
794 sndbuf_getpeaks(struct snd_dbuf *b, int *lp, int *rp)
795 {
796 	u_int32_t lpeak, rpeak;
797 
798 	lpeak = 0;
799 	rpeak = 0;
800 
801 	/**
802 	 * @todo fill this in later
803 	 */
804 }
805 #endif
806