[GitHub/mt8127/android_kernel_alcatel_ttab.git] / sound / core / oss / rate.c

/*
 *  Rate conversion Plug-In
 *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */
  
#include <sound/driver.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include "pcm_plugin.h"

#define SHIFT	11
#define BITS	(1<<SHIFT)
#define R_MASK	(BITS-1)

/*
 *  Basic rate conversion plugin
 */

struct rate_channel {
	signed short last_S1;
	signed short last_S2;
};
 
typedef void (*rate_f)(struct snd_pcm_plugin *plugin,
		       const struct snd_pcm_plugin_channel *src_channels,
		       struct snd_pcm_plugin_channel *dst_channels,
		       int src_frames, int dst_frames);

struct rate_priv {
	unsigned int pitch;
	unsigned int pos;
	rate_f func;
	snd_pcm_sframes_t old_src_frames, old_dst_frames;
	struct rate_channel channels[0];
};

static void rate_init(struct snd_pcm_plugin *plugin)
{
	unsigned int channel;
	struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
	data->pos = 0;
	for (channel = 0; channel < plugin->src_format.channels; channel++) {
		data->channels[channel].last_S1 = 0;
		data->channels[channel].last_S2 = 0;
	}
}

static void resample_expand(struct snd_pcm_plugin *plugin,
			    const struct snd_pcm_plugin_channel *src_channels,
			    struct snd_pcm_plugin_channel *dst_channels,
			    int src_frames, int dst_frames)
{
	unsigned int pos = 0;
	signed int val;
	signed short S1, S2;
	signed short *src, *dst;
	unsigned int channel;
	int src_step, dst_step;
	int src_frames1, dst_frames1;
	struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
	struct rate_channel *rchannels = data->channels;
	
	for (channel = 0; channel < plugin->src_format.channels; channel++) {
		pos = data->pos;
		S1 = rchannels->last_S1;
		S2 = rchannels->last_S2;
		if (!src_channels[channel].enabled) {
			if (dst_channels[channel].wanted)
				snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
			dst_channels[channel].enabled = 0;
			continue;
		}
		dst_channels[channel].enabled = 1;
		src = (signed short *)src_channels[channel].area.addr +
			src_channels[channel].area.first / 8 / 2;
		dst = (signed short *)dst_channels[channel].area.addr +
			dst_channels[channel].area.first / 8 / 2;
		src_step = src_channels[channel].area.step / 8 / 2;
		dst_step = dst_channels[channel].area.step / 8 / 2;
		src_frames1 = src_frames;
		dst_frames1 = dst_frames;
		while (dst_frames1-- > 0) {
			if (pos & ~R_MASK) {
				pos &= R_MASK;
				S1 = S2;
				if (src_frames1-- > 0) {
					S2 = *src;
					src += src_step;
				}
			}
			val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
			if (val < -32768)
				val = -32768;
			else if (val > 32767)
				val = 32767;
			*dst = val;
			dst += dst_step;
			pos += data->pitch;
		}
		rchannels->last_S1 = S1;
		rchannels->last_S2 = S2;
		rchannels++;
	}
	data->pos = pos;
}

static void resample_shrink(struct snd_pcm_plugin *plugin,
			    const struct snd_pcm_plugin_channel *src_channels,
			    struct snd_pcm_plugin_channel *dst_channels,
			    int src_frames, int dst_frames)
{
	unsigned int pos = 0;
	signed int val;
	signed short S1, S2;
	signed short *src, *dst;
	unsigned int channel;
	int src_step, dst_step;
	int src_frames1, dst_frames1;
	struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
	struct rate_channel *rchannels = data->channels;

	for (channel = 0; channel < plugin->src_format.channels; ++channel) {
		pos = data->pos;
		S1 = rchannels->last_S1;
		S2 = rchannels->last_S2;
		if (!src_channels[channel].enabled) {
			if (dst_channels[channel].wanted)
				snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
			dst_channels[channel].enabled = 0;
			continue;
		}
		dst_channels[channel].enabled = 1;
		src = (signed short *)src_channels[channel].area.addr +
			src_channels[channel].area.first / 8 / 2;
		dst = (signed short *)dst_channels[channel].area.addr +
			dst_channels[channel].area.first / 8 / 2;
		src_step = src_channels[channel].area.step / 8 / 2;
		dst_step = dst_channels[channel].area.step / 8 / 2;
		src_frames1 = src_frames;
		dst_frames1 = dst_frames;
		while (dst_frames1 > 0) {
			S1 = S2;
			if (src_frames1-- > 0) {
				S1 = *src;
				src += src_step;
			}
			if (pos & ~R_MASK) {
				pos &= R_MASK;
				val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
				if (val < -32768)
					val = -32768;
				else if (val > 32767)
					val = 32767;
				*dst = val;
				dst += dst_step;
				dst_frames1--;
			}
			pos += data->pitch;
		}
		rchannels->last_S1 = S1;
		rchannels->last_S2 = S2;
		rchannels++;
	}
	data->pos = pos;
}

static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
{
	struct rate_priv *data;
	snd_pcm_sframes_t res;

	snd_assert(plugin != NULL, return -ENXIO);
	if (frames == 0)
		return 0;
	data = (struct rate_priv *)plugin->extra_data;
	if (plugin->src_format.rate < plugin->dst_format.rate) {
		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
	} else {
		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);		
	}
	if (data->old_src_frames > 0) {
		snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
		while (data->old_src_frames < frames1) {
			frames1 >>= 1;
			res1 <<= 1;
		}
		while (data->old_src_frames > frames1) {
			frames1 <<= 1;
			res1 >>= 1;
		}
		if (data->old_src_frames == frames1)
			return res1;
	}
	data->old_src_frames = frames;
	data->old_dst_frames = res;
	return res;
}

static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
{
	struct rate_priv *data;
	snd_pcm_sframes_t res;

	snd_assert(plugin != NULL, return -ENXIO);
	if (frames == 0)
		return 0;
	data = (struct rate_priv *)plugin->extra_data;
	if (plugin->src_format.rate < plugin->dst_format.rate) {
		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
	} else {
		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
	}
	if (data->old_dst_frames > 0) {
		snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;
		while (data->old_dst_frames < frames1) {
			frames1 >>= 1;
			res1 <<= 1;
		}
		while (data->old_dst_frames > frames1) {
			frames1 <<= 1;
			res1 >>= 1;
		}
		if (data->old_dst_frames == frames1)
			return res1;
	}
	data->old_dst_frames = frames;
	data->old_src_frames = res;
	return res;
}

static snd_pcm_sframes_t rate_transfer(struct snd_pcm_plugin *plugin,
			     const struct snd_pcm_plugin_channel *src_channels,
			     struct snd_pcm_plugin_channel *dst_channels,
			     snd_pcm_uframes_t frames)
{
	snd_pcm_uframes_t dst_frames;
	struct rate_priv *data;

	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
	if (frames == 0)
		return 0;
#ifdef CONFIG_SND_DEBUG
	{
		unsigned int channel;
		for (channel = 0; channel < plugin->src_format.channels; channel++) {
			snd_assert(src_channels[channel].area.first % 8 == 0 &&
				   src_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
			snd_assert(dst_channels[channel].area.first % 8 == 0 &&
				   dst_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
		}
	}
#endif

	dst_frames = rate_dst_frames(plugin, frames);
	if (dst_frames > dst_channels[0].frames)
		dst_frames = dst_channels[0].frames;
	data = (struct rate_priv *)plugin->extra_data;
	data->func(plugin, src_channels, dst_channels, frames, dst_frames);
	return dst_frames;
}

static int rate_action(struct snd_pcm_plugin *plugin,
		       enum snd_pcm_plugin_action action,
		       unsigned long udata)
{
	snd_assert(plugin != NULL, return -ENXIO);
	switch (action) {
	case INIT:
	case PREPARE:
		rate_init(plugin);
		break;
	default:
		break;
	}
	return 0;	/* silenty ignore other actions */
}

int snd_pcm_plugin_build_rate(struct snd_pcm_substream *plug,
			      struct snd_pcm_plugin_format *src_format,
			      struct snd_pcm_plugin_format *dst_format,
			      struct snd_pcm_plugin **r_plugin)
{
	int err;
	struct rate_priv *data;
	struct snd_pcm_plugin *plugin;

	snd_assert(r_plugin != NULL, return -ENXIO);
	*r_plugin = NULL;

	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
	snd_assert(src_format->channels > 0, return -ENXIO);
	snd_assert(src_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
	snd_assert(dst_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
	snd_assert(src_format->rate != dst_format->rate, return -ENXIO);

	err = snd_pcm_plugin_build(plug, "rate conversion",
				   src_format, dst_format,
				   sizeof(struct rate_priv) +
				   src_format->channels * sizeof(struct rate_channel),
				   &plugin);
	if (err < 0)
		return err;
	data = (struct rate_priv *)plugin->extra_data;
	if (src_format->rate < dst_format->rate) {
		data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;
		data->func = resample_expand;
	} else {
		data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;
		data->func = resample_shrink;
	}
	data->pos = 0;
	rate_init(plugin);
	data->old_src_frames = data->old_dst_frames = 0;
	plugin->transfer = rate_transfer;
	plugin->src_frames = rate_src_frames;
	plugin->dst_frames = rate_dst_frames;
	plugin->action = rate_action;
	*r_plugin = plugin;
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* Rate conversion Plug-In
c1017a4c	3	* Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
1da177e4 LT	4	*
	5	*
	6	* This library is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU Library General Public License as
	8	* published by the Free Software Foundation; either version 2 of
	9	* the License, or (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU Library General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Library General Public
	17	* License along with this library; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*
	20	*/
	21
	22	#include <sound/driver.h>
	23	#include <linux/time.h>
	24	#include <sound/core.h>
	25	#include <sound/pcm.h>
	26	#include "pcm_plugin.h"
	27
	28	#define SHIFT 11
	29	#define BITS (1<<SHIFT)
	30	#define R_MASK (BITS-1)
	31
	32	/*
	33	* Basic rate conversion plugin
	34	*/
	35
6ac77bc1	36	struct rate_channel {
1da177e4 LT	37	signed short last_S1;
1da177e4 LT	38	signed short last_S2;
6ac77bc1	39	};
1da177e4	40
6ac77bc1 TI	41	typedef void (rate_f)(struct snd_pcm_plugin plugin,
	42	const struct snd_pcm_plugin_channel *src_channels,
	43	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	44	int src_frames, int dst_frames);
1da177e4 LT	45
6ac77bc1	46	struct rate_priv {
1da177e4 LT	47	unsigned int pitch;
	48	unsigned int pos;
	49	rate_f func;
1da177e4	50	snd_pcm_sframes_t old_src_frames, old_dst_frames;
6ac77bc1 TI	51	struct rate_channel channels[0];
6ac77bc1 TI	52	};
1da177e4	53
6ac77bc1	54	static void rate_init(struct snd_pcm_plugin *plugin)
1da177e4 LT	55	{
1da177e4 LT	56	unsigned int channel;
6ac77bc1	57	struct rate_priv data = (struct rate_priv )plugin->extra_data;
1da177e4 LT	58	data->pos = 0;
	59	for (channel = 0; channel < plugin->src_format.channels; channel++) {
	60	data->channels[channel].last_S1 = 0;
	61	data->channels[channel].last_S2 = 0;
	62	}
	63	}
	64
6ac77bc1 TI	65	static void resample_expand(struct snd_pcm_plugin *plugin,
	66	const struct snd_pcm_plugin_channel *src_channels,
	67	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	68	int src_frames, int dst_frames)
	69	{
	70	unsigned int pos = 0;
	71	signed int val;
	72	signed short S1, S2;
0534ab42	73	signed short src, dst;
1da177e4 LT	74	unsigned int channel;
	75	int src_step, dst_step;
	76	int src_frames1, dst_frames1;
6ac77bc1 TI	77	struct rate_priv data = (struct rate_priv )plugin->extra_data;
6ac77bc1 TI	78	struct rate_channel *rchannels = data->channels;
1da177e4 LT	79
	80	for (channel = 0; channel < plugin->src_format.channels; channel++) {
	81	pos = data->pos;
	82	S1 = rchannels->last_S1;
	83	S2 = rchannels->last_S2;
	84	if (!src_channels[channel].enabled) {
	85	if (dst_channels[channel].wanted)
	86	snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
	87	dst_channels[channel].enabled = 0;
	88	continue;
	89	}
	90	dst_channels[channel].enabled = 1;
0534ab42 TI	91	src = (signed short *)src_channels[channel].area.addr +
	92	src_channels[channel].area.first / 8 / 2;
	93	dst = (signed short *)dst_channels[channel].area.addr +
	94	dst_channels[channel].area.first / 8 / 2;
	95	src_step = src_channels[channel].area.step / 8 / 2;
	96	dst_step = dst_channels[channel].area.step / 8 / 2;
1da177e4 LT	97	src_frames1 = src_frames;
	98	dst_frames1 = dst_frames;
	99	while (dst_frames1-- > 0) {
	100	if (pos & ~R_MASK) {
	101	pos &= R_MASK;
	102	S1 = S2;
	103	if (src_frames1-- > 0) {
0534ab42	104	S2 = *src;
1da177e4 LT	105	src += src_step;
	106	}
	107	}
	108	val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
	109	if (val < -32768)
	110	val = -32768;
	111	else if (val > 32767)
	112	val = 32767;
0534ab42	113	*dst = val;
1da177e4 LT	114	dst += dst_step;
	115	pos += data->pitch;
	116	}
	117	rchannels->last_S1 = S1;
	118	rchannels->last_S2 = S2;
	119	rchannels++;
	120	}
	121	data->pos = pos;
	122	}
	123
6ac77bc1 TI	124	static void resample_shrink(struct snd_pcm_plugin *plugin,
	125	const struct snd_pcm_plugin_channel *src_channels,
	126	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	127	int src_frames, int dst_frames)
	128	{
	129	unsigned int pos = 0;
	130	signed int val;
	131	signed short S1, S2;
0534ab42	132	signed short src, dst;
1da177e4 LT	133	unsigned int channel;
	134	int src_step, dst_step;
	135	int src_frames1, dst_frames1;
6ac77bc1 TI	136	struct rate_priv data = (struct rate_priv )plugin->extra_data;
6ac77bc1 TI	137	struct rate_channel *rchannels = data->channels;
1da177e4 LT	138
	139	for (channel = 0; channel < plugin->src_format.channels; ++channel) {
	140	pos = data->pos;
	141	S1 = rchannels->last_S1;
	142	S2 = rchannels->last_S2;
	143	if (!src_channels[channel].enabled) {
	144	if (dst_channels[channel].wanted)
	145	snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
	146	dst_channels[channel].enabled = 0;
	147	continue;
	148	}
	149	dst_channels[channel].enabled = 1;
0534ab42 TI	150	src = (signed short *)src_channels[channel].area.addr +
	151	src_channels[channel].area.first / 8 / 2;
	152	dst = (signed short *)dst_channels[channel].area.addr +
	153	dst_channels[channel].area.first / 8 / 2;
	154	src_step = src_channels[channel].area.step / 8 / 2;
	155	dst_step = dst_channels[channel].area.step / 8 / 2;
1da177e4 LT	156	src_frames1 = src_frames;
	157	dst_frames1 = dst_frames;
	158	while (dst_frames1 > 0) {
	159	S1 = S2;
	160	if (src_frames1-- > 0) {
0534ab42	161	S1 = *src;
1da177e4 LT	162	src += src_step;
	163	}
	164	if (pos & ~R_MASK) {
	165	pos &= R_MASK;
	166	val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
	167	if (val < -32768)
	168	val = -32768;
	169	else if (val > 32767)
	170	val = 32767;
0534ab42	171	*dst = val;
1da177e4 LT	172	dst += dst_step;
	173	dst_frames1--;
	174	}
	175	pos += data->pitch;
	176	}
	177	rchannels->last_S1 = S1;
	178	rchannels->last_S2 = S2;
	179	rchannels++;
	180	}
	181	data->pos = pos;
	182	}
	183
6ac77bc1	184	static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
1da177e4	185	{
6ac77bc1	186	struct rate_priv *data;
1da177e4 LT	187	snd_pcm_sframes_t res;
	188
	189	snd_assert(plugin != NULL, return -ENXIO);
	190	if (frames == 0)
	191	return 0;
6ac77bc1	192	data = (struct rate_priv *)plugin->extra_data;
1da177e4 LT	193	if (plugin->src_format.rate < plugin->dst_format.rate) {
	194	res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
	195	} else {
	196	res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
	197	}
	198	if (data->old_src_frames > 0) {
	199	snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
	200	while (data->old_src_frames < frames1) {
	201	frames1 >>= 1;
	202	res1 <<= 1;
	203	}
	204	while (data->old_src_frames > frames1) {
	205	frames1 <<= 1;
	206	res1 >>= 1;
	207	}
	208	if (data->old_src_frames == frames1)
	209	return res1;
	210	}
	211	data->old_src_frames = frames;
	212	data->old_dst_frames = res;
	213	return res;
	214	}
	215
6ac77bc1	216	static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
1da177e4	217	{
6ac77bc1	218	struct rate_priv *data;
1da177e4 LT	219	snd_pcm_sframes_t res;
	220
	221	snd_assert(plugin != NULL, return -ENXIO);
	222	if (frames == 0)
	223	return 0;
6ac77bc1	224	data = (struct rate_priv *)plugin->extra_data;
1da177e4 LT	225	if (plugin->src_format.rate < plugin->dst_format.rate) {
	226	res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
	227	} else {
	228	res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
	229	}
	230	if (data->old_dst_frames > 0) {
	231	snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;
	232	while (data->old_dst_frames < frames1) {
	233	frames1 >>= 1;
	234	res1 <<= 1;
	235	}
	236	while (data->old_dst_frames > frames1) {
	237	frames1 <<= 1;
	238	res1 >>= 1;
	239	}
	240	if (data->old_dst_frames == frames1)
	241	return res1;
	242	}
	243	data->old_dst_frames = frames;
	244	data->old_src_frames = res;
	245	return res;
	246	}
	247
6ac77bc1 TI	248	static snd_pcm_sframes_t rate_transfer(struct snd_pcm_plugin *plugin,
	249	const struct snd_pcm_plugin_channel *src_channels,
	250	struct snd_pcm_plugin_channel *dst_channels,
1da177e4 LT	251	snd_pcm_uframes_t frames)
	252	{
	253	snd_pcm_uframes_t dst_frames;
6ac77bc1	254	struct rate_priv *data;
1da177e4 LT	255
	256	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
	257	if (frames == 0)
	258	return 0;
	259	#ifdef CONFIG_SND_DEBUG
	260	{
	261	unsigned int channel;
	262	for (channel = 0; channel < plugin->src_format.channels; channel++) {
	263	snd_assert(src_channels[channel].area.first % 8 == 0 &&
	264	src_channels[channel].area.step % 8 == 0,
	265	return -ENXIO);
	266	snd_assert(dst_channels[channel].area.first % 8 == 0 &&
	267	dst_channels[channel].area.step % 8 == 0,
	268	return -ENXIO);
	269	}
	270	}
	271	#endif
	272
	273	dst_frames = rate_dst_frames(plugin, frames);
	274	if (dst_frames > dst_channels[0].frames)
	275	dst_frames = dst_channels[0].frames;
6ac77bc1	276	data = (struct rate_priv *)plugin->extra_data;
1da177e4 LT	277	data->func(plugin, src_channels, dst_channels, frames, dst_frames);
	278	return dst_frames;
	279	}
	280
6ac77bc1 TI	281	static int rate_action(struct snd_pcm_plugin *plugin,
6ac77bc1 TI	282	enum snd_pcm_plugin_action action,
47eaebfd	283	unsigned long udata)
1da177e4 LT	284	{
	285	snd_assert(plugin != NULL, return -ENXIO);
	286	switch (action) {
	287	case INIT:
	288	case PREPARE:
	289	rate_init(plugin);
	290	break;
	291	default:
	292	break;
	293	}
	294	return 0; /* silenty ignore other actions */
	295	}
	296
6ac77bc1 TI	297	int snd_pcm_plugin_build_rate(struct snd_pcm_substream *plug,
	298	struct snd_pcm_plugin_format *src_format,
	299	struct snd_pcm_plugin_format *dst_format,
	300	struct snd_pcm_plugin **r_plugin)
1da177e4 LT	301	{
1da177e4 LT	302	int err;
6ac77bc1 TI	303	struct rate_priv *data;
6ac77bc1 TI	304	struct snd_pcm_plugin *plugin;
1da177e4 LT	305
	306	snd_assert(r_plugin != NULL, return -ENXIO);
	307	*r_plugin = NULL;
	308
	309	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
	310	snd_assert(src_format->channels > 0, return -ENXIO);
0534ab42 TI	311	snd_assert(src_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
0534ab42 TI	312	snd_assert(dst_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
1da177e4 LT	313	snd_assert(src_format->rate != dst_format->rate, return -ENXIO);
	314
	315	err = snd_pcm_plugin_build(plug, "rate conversion",
	316	src_format, dst_format,
6ac77bc1 TI	317	sizeof(struct rate_priv) +
6ac77bc1 TI	318	src_format->channels * sizeof(struct rate_channel),
1da177e4 LT	319	&plugin);
	320	if (err < 0)
	321	return err;
6ac77bc1	322	data = (struct rate_priv *)plugin->extra_data;
1da177e4 LT	323	if (src_format->rate < dst_format->rate) {
	324	data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;
	325	data->func = resample_expand;
	326	} else {
	327	data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;
	328	data->func = resample_shrink;
	329	}
	330	data->pos = 0;
	331	rate_init(plugin);
	332	data->old_src_frames = data->old_dst_frames = 0;
	333	plugin->transfer = rate_transfer;
	334	plugin->src_frames = rate_src_frames;
	335	plugin->dst_frames = rate_dst_frames;
	336	plugin->action = rate_action;
	337	*r_plugin = plugin;
	338	return 0;
	339	}