xref: /openbmc/linux/sound/core/oss/pcm_plugin.c (revision 96de0e252cedffad61b3cb5e05662c591898e69a)
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 <sound/driver.h>
28 #include <linux/slab.h>
29 #include <linux/time.h>
30 #include <linux/vmalloc.h>
31 #include <sound/core.h>
32 #include <sound/pcm.h>
33 #include <sound/pcm_params.h>
34 #include "pcm_plugin.h"
35 
36 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
37 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
38 
39 /*
40  *  because some cards might have rates "very close", we ignore
41  *  all "resampling" requests within +-5%
42  */
43 static int rate_match(unsigned int src_rate, unsigned int dst_rate)
44 {
45 	unsigned int low = (src_rate * 95) / 100;
46 	unsigned int high = (src_rate * 105) / 100;
47 	return dst_rate >= low && dst_rate <= high;
48 }
49 
50 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
51 {
52 	struct snd_pcm_plugin_format *format;
53 	ssize_t width;
54 	size_t size;
55 	unsigned int channel;
56 	struct snd_pcm_plugin_channel *c;
57 
58 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
59 		format = &plugin->src_format;
60 	} else {
61 		format = &plugin->dst_format;
62 	}
63 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
64 		return width;
65 	size = frames * format->channels * width;
66 	snd_assert((size % 8) == 0, return -ENXIO);
67 	size /= 8;
68 	if (plugin->buf_frames < frames) {
69 		vfree(plugin->buf);
70 		plugin->buf = vmalloc(size);
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 		snd_assert((size % format->channels) == 0,);
89 		size /= format->channels;
90 		for (channel = 0; channel < format->channels; channel++, c++) {
91 			c->frames = frames;
92 			c->enabled = 1;
93 			c->wanted = 0;
94 			c->area.addr = plugin->buf + (channel * size);
95 			c->area.first = 0;
96 			c->area.step = width;
97 		}
98 	} else
99 		return -EINVAL;
100 	return 0;
101 }
102 
103 int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
104 {
105 	int err;
106 	snd_assert(snd_pcm_plug_first(plug) != NULL, return -ENXIO);
107 	if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
108 		struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
109 		while (plugin->next) {
110 			if (plugin->dst_frames)
111 				frames = plugin->dst_frames(plugin, frames);
112 			snd_assert(frames > 0, return -ENXIO);
113 			plugin = plugin->next;
114 			err = snd_pcm_plugin_alloc(plugin, frames);
115 			if (err < 0)
116 				return err;
117 		}
118 	} else {
119 		struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
120 		while (plugin->prev) {
121 			if (plugin->src_frames)
122 				frames = plugin->src_frames(plugin, frames);
123 			snd_assert(frames > 0, return -ENXIO);
124 			plugin = plugin->prev;
125 			err = snd_pcm_plugin_alloc(plugin, frames);
126 			if (err < 0)
127 				return err;
128 		}
129 	}
130 	return 0;
131 }
132 
133 
134 snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
135 				       snd_pcm_uframes_t frames,
136 				       struct snd_pcm_plugin_channel **channels)
137 {
138 	*channels = plugin->buf_channels;
139 	return frames;
140 }
141 
142 int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
143 			 const char *name,
144 			 struct snd_pcm_plugin_format *src_format,
145 			 struct snd_pcm_plugin_format *dst_format,
146 			 size_t extra,
147 			 struct snd_pcm_plugin **ret)
148 {
149 	struct snd_pcm_plugin *plugin;
150 	unsigned int channels;
151 
152 	snd_assert(plug != NULL, return -ENXIO);
153 	snd_assert(src_format != NULL && dst_format != NULL, return -ENXIO);
154 	plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
155 	if (plugin == NULL)
156 		return -ENOMEM;
157 	plugin->name = name;
158 	plugin->plug = plug;
159 	plugin->stream = snd_pcm_plug_stream(plug);
160 	plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
161 	plugin->src_format = *src_format;
162 	plugin->src_width = snd_pcm_format_physical_width(src_format->format);
163 	snd_assert(plugin->src_width > 0, );
164 	plugin->dst_format = *dst_format;
165 	plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
166 	snd_assert(plugin->dst_width > 0, );
167 	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
168 		channels = src_format->channels;
169 	else
170 		channels = dst_format->channels;
171 	plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
172 	if (plugin->buf_channels == NULL) {
173 		snd_pcm_plugin_free(plugin);
174 		return -ENOMEM;
175 	}
176 	plugin->client_channels = snd_pcm_plugin_client_channels;
177 	*ret = plugin;
178 	return 0;
179 }
180 
181 int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
182 {
183 	if (! plugin)
184 		return 0;
185 	if (plugin->private_free)
186 		plugin->private_free(plugin);
187 	kfree(plugin->buf_channels);
188 	vfree(plugin->buf);
189 	kfree(plugin);
190 	return 0;
191 }
192 
193 snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
194 {
195 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
196 	int stream = snd_pcm_plug_stream(plug);
197 
198 	snd_assert(plug != NULL, return -ENXIO);
199 	if (drv_frames == 0)
200 		return 0;
201 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
202 		plugin = snd_pcm_plug_last(plug);
203 		while (plugin && drv_frames > 0) {
204 			plugin_prev = plugin->prev;
205 			if (plugin->src_frames)
206 				drv_frames = plugin->src_frames(plugin, drv_frames);
207 			plugin = plugin_prev;
208 		}
209 	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
210 		plugin = snd_pcm_plug_first(plug);
211 		while (plugin && drv_frames > 0) {
212 			plugin_next = plugin->next;
213 			if (plugin->dst_frames)
214 				drv_frames = plugin->dst_frames(plugin, drv_frames);
215 			plugin = plugin_next;
216 		}
217 	} else
218 		snd_BUG();
219 	return drv_frames;
220 }
221 
222 snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
223 {
224 	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
225 	snd_pcm_sframes_t frames;
226 	int stream = snd_pcm_plug_stream(plug);
227 
228 	snd_assert(plug != NULL, return -ENXIO);
229 	if (clt_frames == 0)
230 		return 0;
231 	frames = clt_frames;
232 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
233 		plugin = snd_pcm_plug_first(plug);
234 		while (plugin && frames > 0) {
235 			plugin_next = plugin->next;
236 			if (plugin->dst_frames) {
237 				frames = plugin->dst_frames(plugin, frames);
238 				if (frames < 0)
239 					return frames;
240 			}
241 			plugin = plugin_next;
242 		}
243 	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
244 		plugin = snd_pcm_plug_last(plug);
245 		while (plugin) {
246 			plugin_prev = plugin->prev;
247 			if (plugin->src_frames) {
248 				frames = plugin->src_frames(plugin, frames);
249 				if (frames < 0)
250 					return frames;
251 			}
252 			plugin = plugin_prev;
253 		}
254 	} else
255 		snd_BUG();
256 	return frames;
257 }
258 
259 static int snd_pcm_plug_formats(struct snd_mask *mask, int format)
260 {
261 	struct snd_mask formats = *mask;
262 	u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
263 		       SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
264 		       SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
265 		       SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
266 		       SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
267 		       SNDRV_PCM_FMTBIT_U24_3LE | SNDRV_PCM_FMTBIT_S24_3LE |
268 		       SNDRV_PCM_FMTBIT_U24_3BE | SNDRV_PCM_FMTBIT_S24_3BE |
269 		       SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
270 		       SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
271 	snd_mask_set(&formats, SNDRV_PCM_FORMAT_MU_LAW);
272 
273 	if (formats.bits[0] & (u32)linfmts)
274 		formats.bits[0] |= (u32)linfmts;
275 	if (formats.bits[1] & (u32)(linfmts >> 32))
276 		formats.bits[1] |= (u32)(linfmts >> 32);
277 	return snd_mask_test(&formats, format);
278 }
279 
280 static int preferred_formats[] = {
281 	SNDRV_PCM_FORMAT_S16_LE,
282 	SNDRV_PCM_FORMAT_S16_BE,
283 	SNDRV_PCM_FORMAT_U16_LE,
284 	SNDRV_PCM_FORMAT_U16_BE,
285 	SNDRV_PCM_FORMAT_S24_3LE,
286 	SNDRV_PCM_FORMAT_S24_3BE,
287 	SNDRV_PCM_FORMAT_U24_3LE,
288 	SNDRV_PCM_FORMAT_U24_3BE,
289 	SNDRV_PCM_FORMAT_S24_LE,
290 	SNDRV_PCM_FORMAT_S24_BE,
291 	SNDRV_PCM_FORMAT_U24_LE,
292 	SNDRV_PCM_FORMAT_U24_BE,
293 	SNDRV_PCM_FORMAT_S32_LE,
294 	SNDRV_PCM_FORMAT_S32_BE,
295 	SNDRV_PCM_FORMAT_U32_LE,
296 	SNDRV_PCM_FORMAT_U32_BE,
297 	SNDRV_PCM_FORMAT_S8,
298 	SNDRV_PCM_FORMAT_U8
299 };
300 
301 int snd_pcm_plug_slave_format(int format, struct snd_mask *format_mask)
302 {
303 	int i;
304 
305 	if (snd_mask_test(format_mask, format))
306 		return format;
307 	if (! snd_pcm_plug_formats(format_mask, format))
308 		return -EINVAL;
309 	if (snd_pcm_format_linear(format)) {
310 		unsigned int width = snd_pcm_format_width(format);
311 		int unsignd = snd_pcm_format_unsigned(format) > 0;
312 		int big = snd_pcm_format_big_endian(format) > 0;
313 		unsigned int badness, best = -1;
314 		int best_format = -1;
315 		for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
316 			int f = preferred_formats[i];
317 			unsigned int w;
318 			if (!snd_mask_test(format_mask, f))
319 				continue;
320 			w = snd_pcm_format_width(f);
321 			if (w >= width)
322 				badness = w - width;
323 			else
324 				badness = width - w + 32;
325 			badness += snd_pcm_format_unsigned(f) != unsignd;
326 			badness += snd_pcm_format_big_endian(f) != big;
327 			if (badness < best) {
328 				best_format = f;
329 				best = badness;
330 			}
331 		}
332 		return best_format >= 0 ? best_format : -EINVAL;
333 	} else {
334 		switch (format) {
335 		case SNDRV_PCM_FORMAT_MU_LAW:
336 			for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
337 				int format1 = preferred_formats[i];
338 				if (snd_mask_test(format_mask, format1))
339 					return format1;
340 			}
341 		default:
342 			return -EINVAL;
343 		}
344 	}
345 }
346 
347 int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
348 				struct snd_pcm_hw_params *params,
349 				struct snd_pcm_hw_params *slave_params)
350 {
351 	struct snd_pcm_plugin_format tmpformat;
352 	struct snd_pcm_plugin_format dstformat;
353 	struct snd_pcm_plugin_format srcformat;
354 	int src_access, dst_access;
355 	struct snd_pcm_plugin *plugin = NULL;
356 	int err;
357 	int stream = snd_pcm_plug_stream(plug);
358 	int slave_interleaved = (params_channels(slave_params) == 1 ||
359 				 params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
360 
361 	switch (stream) {
362 	case SNDRV_PCM_STREAM_PLAYBACK:
363 		dstformat.format = params_format(slave_params);
364 		dstformat.rate = params_rate(slave_params);
365 		dstformat.channels = params_channels(slave_params);
366 		srcformat.format = params_format(params);
367 		srcformat.rate = params_rate(params);
368 		srcformat.channels = params_channels(params);
369 		src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
370 		dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
371 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
372 		break;
373 	case SNDRV_PCM_STREAM_CAPTURE:
374 		dstformat.format = params_format(params);
375 		dstformat.rate = params_rate(params);
376 		dstformat.channels = params_channels(params);
377 		srcformat.format = params_format(slave_params);
378 		srcformat.rate = params_rate(slave_params);
379 		srcformat.channels = params_channels(slave_params);
380 		src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
381 						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
382 		dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
383 		break;
384 	default:
385 		snd_BUG();
386 		return -EINVAL;
387 	}
388 	tmpformat = srcformat;
389 
390 	pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
391 		 srcformat.format,
392 		 srcformat.rate,
393 		 srcformat.channels);
394 	pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
395 		 dstformat.format,
396 		 dstformat.rate,
397 		 dstformat.channels);
398 
399 	/* Format change (linearization) */
400 	if (! rate_match(srcformat.rate, dstformat.rate) &&
401 	    ! snd_pcm_format_linear(srcformat.format)) {
402 		if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
403 			return -EINVAL;
404 		tmpformat.format = SNDRV_PCM_FORMAT_S16;
405 		err = snd_pcm_plugin_build_mulaw(plug,
406 						 &srcformat, &tmpformat,
407 						 &plugin);
408 		if (err < 0)
409 			return err;
410 		err = snd_pcm_plugin_append(plugin);
411 		if (err < 0) {
412 			snd_pcm_plugin_free(plugin);
413 			return err;
414 		}
415 		srcformat = tmpformat;
416 		src_access = dst_access;
417 	}
418 
419 	/* channels reduction */
420 	if (srcformat.channels > dstformat.channels) {
421 		tmpformat.channels = dstformat.channels;
422 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
423 		pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
424 		if (err < 0)
425 			return err;
426 		err = snd_pcm_plugin_append(plugin);
427 		if (err < 0) {
428 			snd_pcm_plugin_free(plugin);
429 			return err;
430 		}
431 		srcformat = tmpformat;
432 		src_access = dst_access;
433 	}
434 
435 	/* rate resampling */
436 	if (!rate_match(srcformat.rate, dstformat.rate)) {
437 		if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
438 			/* convert to S16 for resampling */
439 			tmpformat.format = SNDRV_PCM_FORMAT_S16;
440 			err = snd_pcm_plugin_build_linear(plug,
441 							  &srcformat, &tmpformat,
442 							  &plugin);
443 			if (err < 0)
444 				return err;
445 			err = snd_pcm_plugin_append(plugin);
446 			if (err < 0) {
447 				snd_pcm_plugin_free(plugin);
448 				return err;
449 			}
450 			srcformat = tmpformat;
451 			src_access = dst_access;
452 		}
453 		tmpformat.rate = dstformat.rate;
454         	err = snd_pcm_plugin_build_rate(plug,
455         					&srcformat, &tmpformat,
456 						&plugin);
457 		pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
458 		if (err < 0)
459 			return err;
460 		err = snd_pcm_plugin_append(plugin);
461 		if (err < 0) {
462 			snd_pcm_plugin_free(plugin);
463 			return err;
464 		}
465 		srcformat = tmpformat;
466 		src_access = dst_access;
467         }
468 
469 	/* format change */
470 	if (srcformat.format != dstformat.format) {
471 		tmpformat.format = dstformat.format;
472 		if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
473 		    tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
474 			err = snd_pcm_plugin_build_mulaw(plug,
475 							 &srcformat, &tmpformat,
476 							 &plugin);
477 		}
478 		else if (snd_pcm_format_linear(srcformat.format) &&
479 			 snd_pcm_format_linear(tmpformat.format)) {
480 			err = snd_pcm_plugin_build_linear(plug,
481 							  &srcformat, &tmpformat,
482 							  &plugin);
483 		}
484 		else
485 			return -EINVAL;
486 		pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
487 		if (err < 0)
488 			return err;
489 		err = snd_pcm_plugin_append(plugin);
490 		if (err < 0) {
491 			snd_pcm_plugin_free(plugin);
492 			return err;
493 		}
494 		srcformat = tmpformat;
495 		src_access = dst_access;
496 	}
497 
498 	/* channels extension */
499 	if (srcformat.channels < dstformat.channels) {
500 		tmpformat.channels = dstformat.channels;
501 		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
502 		pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
503 		if (err < 0)
504 			return err;
505 		err = snd_pcm_plugin_append(plugin);
506 		if (err < 0) {
507 			snd_pcm_plugin_free(plugin);
508 			return err;
509 		}
510 		srcformat = tmpformat;
511 		src_access = dst_access;
512 	}
513 
514 	/* de-interleave */
515 	if (src_access != dst_access) {
516 		err = snd_pcm_plugin_build_copy(plug,
517 						&srcformat,
518 						&tmpformat,
519 						&plugin);
520 		pdprintf("interleave change (copy: returns %i)\n", err);
521 		if (err < 0)
522 			return err;
523 		err = snd_pcm_plugin_append(plugin);
524 		if (err < 0) {
525 			snd_pcm_plugin_free(plugin);
526 			return err;
527 		}
528 	}
529 
530 	return 0;
531 }
532 
533 snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
534 					 char *buf,
535 					 snd_pcm_uframes_t count,
536 					 struct snd_pcm_plugin_channel **channels)
537 {
538 	struct snd_pcm_plugin *plugin;
539 	struct snd_pcm_plugin_channel *v;
540 	struct snd_pcm_plugin_format *format;
541 	int width, nchannels, channel;
542 	int stream = snd_pcm_plug_stream(plug);
543 
544 	snd_assert(buf != NULL, return -ENXIO);
545 	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
546 		plugin = snd_pcm_plug_first(plug);
547 		format = &plugin->src_format;
548 	} else {
549 		plugin = snd_pcm_plug_last(plug);
550 		format = &plugin->dst_format;
551 	}
552 	v = plugin->buf_channels;
553 	*channels = v;
554 	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
555 		return width;
556 	nchannels = format->channels;
557 	snd_assert(plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED || format->channels <= 1, return -ENXIO);
558 	for (channel = 0; channel < nchannels; channel++, v++) {
559 		v->frames = count;
560 		v->enabled = 1;
561 		v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
562 		v->area.addr = buf;
563 		v->area.first = channel * width;
564 		v->area.step = nchannels * width;
565 	}
566 	return count;
567 }
568 
569 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)
570 {
571 	struct snd_pcm_plugin *plugin, *next;
572 	struct snd_pcm_plugin_channel *dst_channels;
573 	int err;
574 	snd_pcm_sframes_t frames = size;
575 
576 	plugin = snd_pcm_plug_first(plug);
577 	while (plugin && frames > 0) {
578 		if ((next = plugin->next) != NULL) {
579 			snd_pcm_sframes_t frames1 = frames;
580 			if (plugin->dst_frames)
581 				frames1 = plugin->dst_frames(plugin, frames);
582 			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
583 				return err;
584 			}
585 			if (err != frames1) {
586 				frames = err;
587 				if (plugin->src_frames)
588 					frames = plugin->src_frames(plugin, frames1);
589 			}
590 		} else
591 			dst_channels = NULL;
592 		pdprintf("write plugin: %s, %li\n", plugin->name, frames);
593 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
594 			return frames;
595 		src_channels = dst_channels;
596 		plugin = next;
597 	}
598 	return snd_pcm_plug_client_size(plug, frames);
599 }
600 
601 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)
602 {
603 	struct snd_pcm_plugin *plugin, *next;
604 	struct snd_pcm_plugin_channel *src_channels, *dst_channels;
605 	snd_pcm_sframes_t frames = size;
606 	int err;
607 
608 	frames = snd_pcm_plug_slave_size(plug, frames);
609 	if (frames < 0)
610 		return frames;
611 
612 	src_channels = NULL;
613 	plugin = snd_pcm_plug_first(plug);
614 	while (plugin && frames > 0) {
615 		if ((next = plugin->next) != NULL) {
616 			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
617 				return err;
618 			}
619 			frames = err;
620 		} else {
621 			dst_channels = dst_channels_final;
622 		}
623 		pdprintf("read plugin: %s, %li\n", plugin->name, frames);
624 		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
625 			return frames;
626 		plugin = next;
627 		src_channels = dst_channels;
628 	}
629 	return frames;
630 }
631 
632 int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
633 			 size_t samples, int format)
634 {
635 	/* FIXME: sub byte resolution and odd dst_offset */
636 	unsigned char *dst;
637 	unsigned int dst_step;
638 	int width;
639 	const unsigned char *silence;
640 	if (!dst_area->addr)
641 		return 0;
642 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
643 	width = snd_pcm_format_physical_width(format);
644 	if (width <= 0)
645 		return -EINVAL;
646 	if (dst_area->step == (unsigned int) width && width >= 8)
647 		return snd_pcm_format_set_silence(format, dst, samples);
648 	silence = snd_pcm_format_silence_64(format);
649 	if (! silence)
650 		return -EINVAL;
651 	dst_step = dst_area->step / 8;
652 	if (width == 4) {
653 		/* Ima ADPCM */
654 		int dstbit = dst_area->first % 8;
655 		int dstbit_step = dst_area->step % 8;
656 		while (samples-- > 0) {
657 			if (dstbit)
658 				*dst &= 0xf0;
659 			else
660 				*dst &= 0x0f;
661 			dst += dst_step;
662 			dstbit += dstbit_step;
663 			if (dstbit == 8) {
664 				dst++;
665 				dstbit = 0;
666 			}
667 		}
668 	} else {
669 		width /= 8;
670 		while (samples-- > 0) {
671 			memcpy(dst, silence, width);
672 			dst += dst_step;
673 		}
674 	}
675 	return 0;
676 }
677 
678 int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
679 		      const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
680 		      size_t samples, int format)
681 {
682 	/* FIXME: sub byte resolution and odd dst_offset */
683 	char *src, *dst;
684 	int width;
685 	int src_step, dst_step;
686 	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
687 	if (!src_area->addr)
688 		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
689 	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
690 	if (!dst_area->addr)
691 		return 0;
692 	width = snd_pcm_format_physical_width(format);
693 	if (width <= 0)
694 		return -EINVAL;
695 	if (src_area->step == (unsigned int) width &&
696 	    dst_area->step == (unsigned int) width && width >= 8) {
697 		size_t bytes = samples * width / 8;
698 		memcpy(dst, src, bytes);
699 		return 0;
700 	}
701 	src_step = src_area->step / 8;
702 	dst_step = dst_area->step / 8;
703 	if (width == 4) {
704 		/* Ima ADPCM */
705 		int srcbit = src_area->first % 8;
706 		int srcbit_step = src_area->step % 8;
707 		int dstbit = dst_area->first % 8;
708 		int dstbit_step = dst_area->step % 8;
709 		while (samples-- > 0) {
710 			unsigned char srcval;
711 			if (srcbit)
712 				srcval = *src & 0x0f;
713 			else
714 				srcval = (*src & 0xf0) >> 4;
715 			if (dstbit)
716 				*dst = (*dst & 0xf0) | srcval;
717 			else
718 				*dst = (*dst & 0x0f) | (srcval << 4);
719 			src += src_step;
720 			srcbit += srcbit_step;
721 			if (srcbit == 8) {
722 				src++;
723 				srcbit = 0;
724 			}
725 			dst += dst_step;
726 			dstbit += dstbit_step;
727 			if (dstbit == 8) {
728 				dst++;
729 				dstbit = 0;
730 			}
731 		}
732 	} else {
733 		width /= 8;
734 		while (samples-- > 0) {
735 			memcpy(dst, src, width);
736 			src += src_step;
737 			dst += dst_step;
738 		}
739 	}
740 	return 0;
741 }
742