xref: /openbmc/linux/sound/core/oss/pcm_plugin.c (revision f20c7d91)
1 /*
2  *  PCM Plug-In shared (kernel/library) code
3  *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
4  *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
5  *
6  *
7  *   This library is free software; you can redistribute it and/or modify
8  *   it under the terms of the GNU Library General Public License as
9  *   published by the Free Software Foundation; either version 2 of
10  *   the License, or (at your option) any later version.
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU Library General Public License for more details.
16  *
17  *   You should have received a copy of the GNU Library General Public
18  *   License along with this library; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  *
21  */
22 
23 #if 0
24 #define PLUGIN_DEBUG
25 #endif
26 
27 #include <linux/slab.h>
28 #include <linux/time.h>
29 #include <linux/vmalloc.h>
30 #include <sound/core.h>
31 #include <sound/pcm.h>
32 #include <sound/pcm_params.h>
33 #include "pcm_plugin.h"
34 
35 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
36 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
37 
38 /*
39  *  because some cards might have rates "very close", we ignore
40  *  all "resampling" requests within +-5%
41  */
42 static int rate_match(unsigned int src_rate, unsigned int dst_rate)
43 {
44 	unsigned int low = (src_rate * 95) / 100;
45 	unsigned int high = (src_rate * 105) / 100;
46 	return dst_rate >= low && dst_rate <= high;
47 }
48 
49 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
50 {
51 	struct snd_pcm_plugin_format *format;
52 	ssize_t width;
53 	size_t size;
54 	unsigned int channel;
55 	struct snd_pcm_plugin_channel *c;
56 
57 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
58 		format = &plugin->src_format;
59 	} else {
60 		format = &plugin->dst_format;
61 	}
62 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
63 		return width;
64 	size = frames * format->channels * width;
65 	if (snd_BUG_ON(size % 8))
66 		return -ENXIO;
67 	size /= 8;
68 	if (plugin->buf_frames < frames) {
69 		kvfree(plugin->buf);
70 		plugin->buf = kvzalloc(size, GFP_KERNEL);
71 		plugin->buf_frames = frames;
72 	}
73 	if (!plugin->buf) {
74 		plugin->buf_frames = 0;
75 		return -ENOMEM;
76 	}
77 	c = plugin->buf_channels;
78 	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
79 		for (channel = 0; channel < format->channels; channel++, c++) {
80 			c->frames = frames;
81 			c->enabled = 1;
82 			c->wanted = 0;
83 			c->area.addr = plugin->buf;
84 			c->area.first = channel * width;
85 			c->area.step = format->channels * width;
86 		}
87 	} else if (plugin->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED) {
88 		if (snd_BUG_ON(size % format->channels))
89 			return -EINVAL;
90 		size /= format->channels;
91 		for (channel = 0; channel < format->channels; channel++, c++) {
92 			c->frames = frames;
93 			c->enabled = 1;
94 			c->wanted = 0;
95 			c->area.addr = plugin->buf + (channel * size);
96 			c->area.first = 0;
97 			c->area.step = width;
98 		}
99 	} else
100 		return -EINVAL;
101 	return 0;
102 }
103 
104 int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
105 {
106 	int err;
107 	if (snd_BUG_ON(!snd_pcm_plug_first(plug)))
108 		return -ENXIO;
109 	if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
110 		struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
111 		while (plugin->next) {
112 			if (plugin->dst_frames)
113 				frames = plugin->dst_frames(plugin, frames);
114 			if ((snd_pcm_sframes_t)frames <= 0)
115 				return -ENXIO;
116 			plugin = plugin->next;
117 			err = snd_pcm_plugin_alloc(plugin, frames);
118 			if (err < 0)
119 				return err;
120 		}
121 	} else {
122 		struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
123 		while (plugin->prev) {
124 			if (plugin->src_frames)
125 				frames = plugin->src_frames(plugin, frames);
126 			if ((snd_pcm_sframes_t)frames <= 0)
127 				return -ENXIO;
128 			plugin = plugin->prev;
129 			err = snd_pcm_plugin_alloc(plugin, frames);
130 			if (err < 0)
131 				return err;
132 		}
133 	}
134 	return 0;
135 }
136 
137 
138 snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
139 				       snd_pcm_uframes_t frames,
140 				       struct snd_pcm_plugin_channel **channels)
141 {
142 	*channels = plugin->buf_channels;
143 	return frames;
144 }
145 
146 int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
147 			 const char *name,
148 			 struct snd_pcm_plugin_format *src_format,
149 			 struct snd_pcm_plugin_format *dst_format,
150 			 size_t extra,
151 			 struct snd_pcm_plugin **ret)
152 {
153 	struct snd_pcm_plugin *plugin;
154 	unsigned int channels;
155 
156 	if (snd_BUG_ON(!plug))
157 		return -ENXIO;
158 	if (snd_BUG_ON(!src_format || !dst_format))
159 		return -ENXIO;
160 	plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
161 	if (plugin == NULL)
162 		return -ENOMEM;
163 	plugin->name = name;
164 	plugin->plug = plug;
165 	plugin->stream = snd_pcm_plug_stream(plug);
166 	plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
167 	plugin->src_format = *src_format;
168 	plugin->src_width = snd_pcm_format_physical_width(src_format->format);
169 	snd_BUG_ON(plugin->src_width <= 0);
170 	plugin->dst_format = *dst_format;
171 	plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
172 	snd_BUG_ON(plugin->dst_width <= 0);
173 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
174 		channels = src_format->channels;
175 	else
176 		channels = dst_format->channels;
177 	plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
178 	if (plugin->buf_channels == NULL) {
179 		snd_pcm_plugin_free(plugin);
180 		return -ENOMEM;
181 	}
182 	plugin->client_channels = snd_pcm_plugin_client_channels;
183 	*ret = plugin;
184 	return 0;
185 }
186 
187 int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
188 {
189 	if (! plugin)
190 		return 0;
191 	if (plugin->private_free)
192 		plugin->private_free(plugin);
193 	kfree(plugin->buf_channels);
194 	kvfree(plugin->buf);
195 	kfree(plugin);
196 	return 0;
197 }
198 
199 static snd_pcm_sframes_t calc_dst_frames(struct snd_pcm_substream *plug,
200 					 snd_pcm_sframes_t frames,
201 					 bool check_size)
202 {
203 	struct snd_pcm_plugin *plugin, *plugin_next;
204 
205 	plugin = snd_pcm_plug_first(plug);
206 	while (plugin && frames > 0) {
207 		plugin_next = plugin->next;
208 		if (check_size && plugin->buf_frames &&
209 		    frames > plugin->buf_frames)
210 			frames = plugin->buf_frames;
211 		if (plugin->dst_frames) {
212 			frames = plugin->dst_frames(plugin, frames);
213 			if (frames < 0)
214 				return frames;
215 		}
216 		plugin = plugin_next;
217 	}
218 	return frames;
219 }
220 
221 static snd_pcm_sframes_t calc_src_frames(struct snd_pcm_substream *plug,
222 					 snd_pcm_sframes_t frames,
223 					 bool check_size)
224 {
225 	struct snd_pcm_plugin *plugin, *plugin_prev;
226 
227 	plugin = snd_pcm_plug_last(plug);
228 	while (plugin && frames > 0) {
229 		plugin_prev = plugin->prev;
230 		if (plugin->src_frames) {
231 			frames = plugin->src_frames(plugin, frames);
232 			if (frames < 0)
233 				return frames;
234 		}
235 		if (check_size && plugin->buf_frames &&
236 		    frames > plugin->buf_frames)
237 			frames = plugin->buf_frames;
238 		plugin = plugin_prev;
239 	}
240 	return frames;
241 }
242 
243 snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
244 {
245 	if (snd_BUG_ON(!plug))
246 		return -ENXIO;
247 	switch (snd_pcm_plug_stream(plug)) {
248 	case SNDRV_PCM_STREAM_PLAYBACK:
249 		return calc_src_frames(plug, drv_frames, false);
250 	case SNDRV_PCM_STREAM_CAPTURE:
251 		return calc_dst_frames(plug, drv_frames, false);
252 	default:
253 		snd_BUG();
254 		return -EINVAL;
255 	}
256 }
257 
258 snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
259 {
260 	if (snd_BUG_ON(!plug))
261 		return -ENXIO;
262 	switch (snd_pcm_plug_stream(plug)) {
263 	case SNDRV_PCM_STREAM_PLAYBACK:
264 		return calc_dst_frames(plug, clt_frames, false);
265 	case SNDRV_PCM_STREAM_CAPTURE:
266 		return calc_src_frames(plug, clt_frames, false);
267 	default:
268 		snd_BUG();
269 		return -EINVAL;
270 	}
271 }
272 
273 static int snd_pcm_plug_formats(const struct snd_mask *mask,
274 				snd_pcm_format_t format)
275 {
276 	struct snd_mask formats = *mask;
277 	u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
278 		       SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
279 		       SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
280 		       SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
281 		       SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
282 		       SNDRV_PCM_FMTBIT_U24_3LE | SNDRV_PCM_FMTBIT_S24_3LE |
283 		       SNDRV_PCM_FMTBIT_U24_3BE | SNDRV_PCM_FMTBIT_S24_3BE |
284 		       SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
285 		       SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
286 	snd_mask_set(&formats, (__force int)SNDRV_PCM_FORMAT_MU_LAW);
287 
288 	if (formats.bits[0] & lower_32_bits(linfmts))
289 		formats.bits[0] |= lower_32_bits(linfmts);
290 	if (formats.bits[1] & upper_32_bits(linfmts))
291 		formats.bits[1] |= upper_32_bits(linfmts);
292 	return snd_mask_test(&formats, (__force int)format);
293 }
294 
295 static const snd_pcm_format_t preferred_formats[] = {
296 	SNDRV_PCM_FORMAT_S16_LE,
297 	SNDRV_PCM_FORMAT_S16_BE,
298 	SNDRV_PCM_FORMAT_U16_LE,
299 	SNDRV_PCM_FORMAT_U16_BE,
300 	SNDRV_PCM_FORMAT_S24_3LE,
301 	SNDRV_PCM_FORMAT_S24_3BE,
302 	SNDRV_PCM_FORMAT_U24_3LE,
303 	SNDRV_PCM_FORMAT_U24_3BE,
304 	SNDRV_PCM_FORMAT_S24_LE,
305 	SNDRV_PCM_FORMAT_S24_BE,
306 	SNDRV_PCM_FORMAT_U24_LE,
307 	SNDRV_PCM_FORMAT_U24_BE,
308 	SNDRV_PCM_FORMAT_S32_LE,
309 	SNDRV_PCM_FORMAT_S32_BE,
310 	SNDRV_PCM_FORMAT_U32_LE,
311 	SNDRV_PCM_FORMAT_U32_BE,
312 	SNDRV_PCM_FORMAT_S8,
313 	SNDRV_PCM_FORMAT_U8
314 };
315 
316 snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format,
317 					   const struct snd_mask *format_mask)
318 {
319 	int i;
320 
321 	if (snd_mask_test(format_mask, (__force int)format))
322 		return format;
323 	if (!snd_pcm_plug_formats(format_mask, format))
324 		return (__force snd_pcm_format_t)-EINVAL;
325 	if (snd_pcm_format_linear(format)) {
326 		unsigned int width = snd_pcm_format_width(format);
327 		int unsignd = snd_pcm_format_unsigned(format) > 0;
328 		int big = snd_pcm_format_big_endian(format) > 0;
329 		unsigned int badness, best = -1;
330 		snd_pcm_format_t best_format = (__force snd_pcm_format_t)-1;
331 		for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
332 			snd_pcm_format_t f = preferred_formats[i];
333 			unsigned int w;
334 			if (!snd_mask_test(format_mask, (__force int)f))
335 				continue;
336 			w = snd_pcm_format_width(f);
337 			if (w >= width)
338 				badness = w - width;
339 			else
340 				badness = width - w + 32;
341 			badness += snd_pcm_format_unsigned(f) != unsignd;
342 			badness += snd_pcm_format_big_endian(f) != big;
343 			if (badness < best) {
344 				best_format = f;
345 				best = badness;
346 			}
347 		}
348 		if ((__force int)best_format >= 0)
349 			return best_format;
350 		else
351 			return (__force snd_pcm_format_t)-EINVAL;
352 	} else {
353 		switch (format) {
354 		case SNDRV_PCM_FORMAT_MU_LAW:
355 			for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
356 				snd_pcm_format_t format1 = preferred_formats[i];
357 				if (snd_mask_test(format_mask, (__force int)format1))
358 					return format1;
359 			}
360 			/* fall through */
361 		default:
362 			return (__force snd_pcm_format_t)-EINVAL;
363 		}
364 	}
365 }
366 
367 int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
368 				struct snd_pcm_hw_params *params,
369 				struct snd_pcm_hw_params *slave_params)
370 {
371 	struct snd_pcm_plugin_format tmpformat;
372 	struct snd_pcm_plugin_format dstformat;
373 	struct snd_pcm_plugin_format srcformat;
374 	snd_pcm_access_t src_access, dst_access;
375 	struct snd_pcm_plugin *plugin = NULL;
376 	int err;
377 	int stream = snd_pcm_plug_stream(plug);
378 	int slave_interleaved = (params_channels(slave_params) == 1 ||
379 				 params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
380 
381 	switch (stream) {
382 	case SNDRV_PCM_STREAM_PLAYBACK:
383 		dstformat.format = params_format(slave_params);
384 		dstformat.rate = params_rate(slave_params);
385 		dstformat.channels = params_channels(slave_params);
386 		srcformat.format = params_format(params);
387 		srcformat.rate = params_rate(params);
388 		srcformat.channels = params_channels(params);
389 		src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
390 		dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
391 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
392 		break;
393 	case SNDRV_PCM_STREAM_CAPTURE:
394 		dstformat.format = params_format(params);
395 		dstformat.rate = params_rate(params);
396 		dstformat.channels = params_channels(params);
397 		srcformat.format = params_format(slave_params);
398 		srcformat.rate = params_rate(slave_params);
399 		srcformat.channels = params_channels(slave_params);
400 		src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
401 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
402 		dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
403 		break;
404 	default:
405 		snd_BUG();
406 		return -EINVAL;
407 	}
408 	tmpformat = srcformat;
409 
410 	pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
411 		 srcformat.format,
412 		 srcformat.rate,
413 		 srcformat.channels);
414 	pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
415 		 dstformat.format,
416 		 dstformat.rate,
417 		 dstformat.channels);
418 
419 	/* Format change (linearization) */
420 	if (! rate_match(srcformat.rate, dstformat.rate) &&
421 	    ! snd_pcm_format_linear(srcformat.format)) {
422 		if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
423 			return -EINVAL;
424 		tmpformat.format = SNDRV_PCM_FORMAT_S16;
425 		err = snd_pcm_plugin_build_mulaw(plug,
426 						 &srcformat, &tmpformat,
427 						 &plugin);
428 		if (err < 0)
429 			return err;
430 		err = snd_pcm_plugin_append(plugin);
431 		if (err < 0) {
432 			snd_pcm_plugin_free(plugin);
433 			return err;
434 		}
435 		srcformat = tmpformat;
436 		src_access = dst_access;
437 	}
438 
439 	/* channels reduction */
440 	if (srcformat.channels > dstformat.channels) {
441 		tmpformat.channels = dstformat.channels;
442 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
443 		pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
444 		if (err < 0)
445 			return err;
446 		err = snd_pcm_plugin_append(plugin);
447 		if (err < 0) {
448 			snd_pcm_plugin_free(plugin);
449 			return err;
450 		}
451 		srcformat = tmpformat;
452 		src_access = dst_access;
453 	}
454 
455 	/* rate resampling */
456 	if (!rate_match(srcformat.rate, dstformat.rate)) {
457 		if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
458 			/* convert to S16 for resampling */
459 			tmpformat.format = SNDRV_PCM_FORMAT_S16;
460 			err = snd_pcm_plugin_build_linear(plug,
461 							  &srcformat, &tmpformat,
462 							  &plugin);
463 			if (err < 0)
464 				return err;
465 			err = snd_pcm_plugin_append(plugin);
466 			if (err < 0) {
467 				snd_pcm_plugin_free(plugin);
468 				return err;
469 			}
470 			srcformat = tmpformat;
471 			src_access = dst_access;
472 		}
473 		tmpformat.rate = dstformat.rate;
474         	err = snd_pcm_plugin_build_rate(plug,
475         					&srcformat, &tmpformat,
476 						&plugin);
477 		pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
478 		if (err < 0)
479 			return err;
480 		err = snd_pcm_plugin_append(plugin);
481 		if (err < 0) {
482 			snd_pcm_plugin_free(plugin);
483 			return err;
484 		}
485 		srcformat = tmpformat;
486 		src_access = dst_access;
487         }
488 
489 	/* format change */
490 	if (srcformat.format != dstformat.format) {
491 		tmpformat.format = dstformat.format;
492 		if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
493 		    tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
494 			err = snd_pcm_plugin_build_mulaw(plug,
495 							 &srcformat, &tmpformat,
496 							 &plugin);
497 		}
498 		else if (snd_pcm_format_linear(srcformat.format) &&
499 			 snd_pcm_format_linear(tmpformat.format)) {
500 			err = snd_pcm_plugin_build_linear(plug,
501 							  &srcformat, &tmpformat,
502 							  &plugin);
503 		}
504 		else
505 			return -EINVAL;
506 		pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
507 		if (err < 0)
508 			return err;
509 		err = snd_pcm_plugin_append(plugin);
510 		if (err < 0) {
511 			snd_pcm_plugin_free(plugin);
512 			return err;
513 		}
514 		srcformat = tmpformat;
515 		src_access = dst_access;
516 	}
517 
518 	/* channels extension */
519 	if (srcformat.channels < dstformat.channels) {
520 		tmpformat.channels = dstformat.channels;
521 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
522 		pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
523 		if (err < 0)
524 			return err;
525 		err = snd_pcm_plugin_append(plugin);
526 		if (err < 0) {
527 			snd_pcm_plugin_free(plugin);
528 			return err;
529 		}
530 		srcformat = tmpformat;
531 		src_access = dst_access;
532 	}
533 
534 	/* de-interleave */
535 	if (src_access != dst_access) {
536 		err = snd_pcm_plugin_build_copy(plug,
537 						&srcformat,
538 						&tmpformat,
539 						&plugin);
540 		pdprintf("interleave change (copy: returns %i)\n", err);
541 		if (err < 0)
542 			return err;
543 		err = snd_pcm_plugin_append(plugin);
544 		if (err < 0) {
545 			snd_pcm_plugin_free(plugin);
546 			return err;
547 		}
548 	}
549 
550 	return 0;
551 }
552 
553 snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
554 					 char *buf,
555 					 snd_pcm_uframes_t count,
556 					 struct snd_pcm_plugin_channel **channels)
557 {
558 	struct snd_pcm_plugin *plugin;
559 	struct snd_pcm_plugin_channel *v;
560 	struct snd_pcm_plugin_format *format;
561 	int width, nchannels, channel;
562 	int stream = snd_pcm_plug_stream(plug);
563 
564 	if (snd_BUG_ON(!buf))
565 		return -ENXIO;
566 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
567 		plugin = snd_pcm_plug_first(plug);
568 		format = &plugin->src_format;
569 	} else {
570 		plugin = snd_pcm_plug_last(plug);
571 		format = &plugin->dst_format;
572 	}
573 	v = plugin->buf_channels;
574 	*channels = v;
575 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
576 		return width;
577 	nchannels = format->channels;
578 	if (snd_BUG_ON(plugin->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
579 		       format->channels > 1))
580 		return -ENXIO;
581 	for (channel = 0; channel < nchannels; channel++, v++) {
582 		v->frames = count;
583 		v->enabled = 1;
584 		v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
585 		v->area.addr = buf;
586 		v->area.first = channel * width;
587 		v->area.step = nchannels * width;
588 	}
589 	return count;
590 }
591 
592 snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *src_channels, snd_pcm_uframes_t size)
593 {
594 	struct snd_pcm_plugin *plugin, *next;
595 	struct snd_pcm_plugin_channel *dst_channels;
596 	int err;
597 	snd_pcm_sframes_t frames = size;
598 
599 	plugin = snd_pcm_plug_first(plug);
600 	while (plugin) {
601 		if (frames <= 0)
602 			return frames;
603 		if ((next = plugin->next) != NULL) {
604 			snd_pcm_sframes_t frames1 = frames;
605 			if (plugin->dst_frames) {
606 				frames1 = plugin->dst_frames(plugin, frames);
607 				if (frames1 <= 0)
608 					return frames1;
609 			}
610 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
611 				return err;
612 			}
613 			if (err != frames1) {
614 				frames = err;
615 				if (plugin->src_frames) {
616 					frames = plugin->src_frames(plugin, frames1);
617 					if (frames <= 0)
618 						return frames;
619 				}
620 			}
621 		} else
622 			dst_channels = NULL;
623 		pdprintf("write plugin: %s, %li\n", plugin->name, frames);
624 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
625 			return frames;
626 		src_channels = dst_channels;
627 		plugin = next;
628 	}
629 	return calc_src_frames(plug, frames, true);
630 }
631 
632 snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *plug, struct snd_pcm_plugin_channel *dst_channels_final, snd_pcm_uframes_t size)
633 {
634 	struct snd_pcm_plugin *plugin, *next;
635 	struct snd_pcm_plugin_channel *src_channels, *dst_channels;
636 	snd_pcm_sframes_t frames = size;
637 	int err;
638 
639 	frames = calc_src_frames(plug, frames, true);
640 	if (frames < 0)
641 		return frames;
642 
643 	src_channels = NULL;
644 	plugin = snd_pcm_plug_first(plug);
645 	while (plugin && frames > 0) {
646 		if ((next = plugin->next) != NULL) {
647 			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
648 				return err;
649 			}
650 			frames = err;
651 		} else {
652 			dst_channels = dst_channels_final;
653 		}
654 		pdprintf("read plugin: %s, %li\n", plugin->name, frames);
655 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
656 			return frames;
657 		plugin = next;
658 		src_channels = dst_channels;
659 	}
660 	return frames;
661 }
662 
663 int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
664 			 size_t samples, snd_pcm_format_t format)
665 {
666 	/* FIXME: sub byte resolution and odd dst_offset */
667 	unsigned char *dst;
668 	unsigned int dst_step;
669 	int width;
670 	const unsigned char *silence;
671 	if (!dst_area->addr)
672 		return 0;
673 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
674 	width = snd_pcm_format_physical_width(format);
675 	if (width <= 0)
676 		return -EINVAL;
677 	if (dst_area->step == (unsigned int) width && width >= 8)
678 		return snd_pcm_format_set_silence(format, dst, samples);
679 	silence = snd_pcm_format_silence_64(format);
680 	if (! silence)
681 		return -EINVAL;
682 	dst_step = dst_area->step / 8;
683 	if (width == 4) {
684 		/* Ima ADPCM */
685 		int dstbit = dst_area->first % 8;
686 		int dstbit_step = dst_area->step % 8;
687 		while (samples-- > 0) {
688 			if (dstbit)
689 				*dst &= 0xf0;
690 			else
691 				*dst &= 0x0f;
692 			dst += dst_step;
693 			dstbit += dstbit_step;
694 			if (dstbit == 8) {
695 				dst++;
696 				dstbit = 0;
697 			}
698 		}
699 	} else {
700 		width /= 8;
701 		while (samples-- > 0) {
702 			memcpy(dst, silence, width);
703 			dst += dst_step;
704 		}
705 	}
706 	return 0;
707 }
708 
709 int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
710 		      const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
711 		      size_t samples, snd_pcm_format_t format)
712 {
713 	/* FIXME: sub byte resolution and odd dst_offset */
714 	char *src, *dst;
715 	int width;
716 	int src_step, dst_step;
717 	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
718 	if (!src_area->addr)
719 		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
720 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
721 	if (!dst_area->addr)
722 		return 0;
723 	width = snd_pcm_format_physical_width(format);
724 	if (width <= 0)
725 		return -EINVAL;
726 	if (src_area->step == (unsigned int) width &&
727 	    dst_area->step == (unsigned int) width && width >= 8) {
728 		size_t bytes = samples * width / 8;
729 		memcpy(dst, src, bytes);
730 		return 0;
731 	}
732 	src_step = src_area->step / 8;
733 	dst_step = dst_area->step / 8;
734 	if (width == 4) {
735 		/* Ima ADPCM */
736 		int srcbit = src_area->first % 8;
737 		int srcbit_step = src_area->step % 8;
738 		int dstbit = dst_area->first % 8;
739 		int dstbit_step = dst_area->step % 8;
740 		while (samples-- > 0) {
741 			unsigned char srcval;
742 			if (srcbit)
743 				srcval = *src & 0x0f;
744 			else
745 				srcval = (*src & 0xf0) >> 4;
746 			if (dstbit)
747 				*dst = (*dst & 0xf0) | srcval;
748 			else
749 				*dst = (*dst & 0x0f) | (srcval << 4);
750 			src += src_step;
751 			srcbit += srcbit_step;
752 			if (srcbit == 8) {
753 				src++;
754 				srcbit = 0;
755 			}
756 			dst += dst_step;
757 			dstbit += dstbit_step;
758 			if (dstbit == 8) {
759 				dst++;
760 				dstbit = 0;
761 			}
762 		}
763 	} else {
764 		width /= 8;
765 		while (samples-- > 0) {
766 			memcpy(dst, src, width);
767 			src += src_step;
768 			dst += dst_step;
769 		}
770 	}
771 	return 0;
772 }
773