Fixed MTP to work with TWRP

sound/core/oss/Makefile

@@ -0,0 +1,13 @@
+#
+# Makefile for ALSA
+# Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
+#
+
+snd-mixer-oss-objs := mixer_oss.o
+
+snd-pcm-oss-y := pcm_oss.o
+snd-pcm-oss-$(CONFIG_SND_PCM_OSS_PLUGINS) += pcm_plugin.o \
+	io.o copy.o linear.o mulaw.o route.o rate.o
+
+obj-$(CONFIG_SND_MIXER_OSS) += snd-mixer-oss.o
+obj-$(CONFIG_SND_PCM_OSS) += snd-pcm-oss.o

sound/core/oss/copy.c

@@ -0,0 +1,92 @@
+/*
+ *  Linear conversion Plug-In
+ *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
+ *
+ *
+ *   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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include "pcm_plugin.h"
+
+static snd_pcm_sframes_t copy_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)
+{
+	unsigned int channel;
+	unsigned int nchannels;
+
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+	nchannels = plugin->src_format.channels;
+	for (channel = 0; channel < nchannels; channel++) {
+		if (snd_BUG_ON(src_channels->area.first % 8 ||
+			       src_channels->area.step % 8))
+			return -ENXIO;
+		if (snd_BUG_ON(dst_channels->area.first % 8 ||
+			       dst_channels->area.step % 8))
+			return -ENXIO;
+		if (!src_channels->enabled) {
+			if (dst_channels->wanted)
+				snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);
+			dst_channels->enabled = 0;
+			continue;
+		}
+		dst_channels->enabled = 1;
+		snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);
+		src_channels++;
+		dst_channels++;
+	}
+	return frames;
+}
+
+int snd_pcm_plugin_build_copy(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 snd_pcm_plugin *plugin;
+	int width;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+
+	if (snd_BUG_ON(src_format->format != dst_format->format))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->rate != dst_format->rate))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->channels != dst_format->channels))
+		return -ENXIO;
+
+	width = snd_pcm_format_physical_width(src_format->format);
+	if (snd_BUG_ON(width <= 0))
+		return -ENXIO;
+
+	err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
+				   0, &plugin);
+	if (err < 0)
+		return err;
+	plugin->transfer = copy_transfer;
+	*r_plugin = plugin;
+	return 0;
+}

sound/core/oss/io.c

@@ -0,0 +1,141 @@
+/*
+ *  PCM I/O Plug-In Interface
+ *  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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "pcm_plugin.h"
+
+#define pcm_write(plug,buf,count) snd_pcm_oss_write3(plug,buf,count,1)
+#define pcm_writev(plug,vec,count) snd_pcm_oss_writev3(plug,vec,count,1)
+#define pcm_read(plug,buf,count) snd_pcm_oss_read3(plug,buf,count,1)
+#define pcm_readv(plug,vec,count) snd_pcm_oss_readv3(plug,vec,count,1)
+
+/*
+ *  Basic io plugin
+ */
+ 
+static snd_pcm_sframes_t io_playback_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)
+{
+	if (snd_BUG_ON(!plugin))
+		return -ENXIO;
+	if (snd_BUG_ON(!src_channels))
+		return -ENXIO;
+	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
+		return pcm_write(plugin->plug, src_channels->area.addr, frames);
+	} else {
+		int channel, channels = plugin->dst_format.channels;
+		void **bufs = (void**)plugin->extra_data;
+		if (snd_BUG_ON(!bufs))
+			return -ENXIO;
+		for (channel = 0; channel < channels; channel++) {
+			if (src_channels[channel].enabled)
+				bufs[channel] = src_channels[channel].area.addr;
+			else
+				bufs[channel] = NULL;
+		}
+		return pcm_writev(plugin->plug, bufs, frames);
+	}
+}
+ 
+static snd_pcm_sframes_t io_capture_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)
+{
+	if (snd_BUG_ON(!plugin))
+		return -ENXIO;
+	if (snd_BUG_ON(!dst_channels))
+		return -ENXIO;
+	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
+		return pcm_read(plugin->plug, dst_channels->area.addr, frames);
+	} else {
+		int channel, channels = plugin->dst_format.channels;
+		void **bufs = (void**)plugin->extra_data;
+		if (snd_BUG_ON(!bufs))
+			return -ENXIO;
+		for (channel = 0; channel < channels; channel++) {
+			if (dst_channels[channel].enabled)
+				bufs[channel] = dst_channels[channel].area.addr;
+			else
+				bufs[channel] = NULL;
+		}
+		return pcm_readv(plugin->plug, bufs, frames);
+	}
+	return 0;
+}
+ 
+static snd_pcm_sframes_t io_src_channels(struct snd_pcm_plugin *plugin,
+			     snd_pcm_uframes_t frames,
+			     struct snd_pcm_plugin_channel **channels)
+{
+	int err;
+	unsigned int channel;
+	struct snd_pcm_plugin_channel *v;
+	err = snd_pcm_plugin_client_channels(plugin, frames, &v);
+	if (err < 0)
+		return err;
+	*channels = v;
+	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
+		for (channel = 0; channel < plugin->src_format.channels; ++channel, ++v)
+			v->wanted = 1;
+	}
+	return frames;
+}
+
+int snd_pcm_plugin_build_io(struct snd_pcm_substream *plug,
+			    struct snd_pcm_hw_params *params,
+			    struct snd_pcm_plugin **r_plugin)
+{
+	int err;
+	struct snd_pcm_plugin_format format;
+	struct snd_pcm_plugin *plugin;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+	if (snd_BUG_ON(!plug || !params))
+		return -ENXIO;
+	format.format = params_format(params);
+	format.rate = params_rate(params);
+	format.channels = params_channels(params);
+	err = snd_pcm_plugin_build(plug, "I/O io",
+				   &format, &format,
+				   sizeof(void *) * format.channels,
+				   &plugin);
+	if (err < 0)
+		return err;
+	plugin->access = params_access(params);
+	if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
+		plugin->transfer = io_playback_transfer;
+		if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED)
+			plugin->client_channels = io_src_channels;
+	} else {
+		plugin->transfer = io_capture_transfer;
+	}
+
+	*r_plugin = plugin;
+	return 0;
+}

sound/core/oss/linear.c

@@ -0,0 +1,178 @@
+/*
+ *  Linear conversion Plug-In
+ *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>,
+ *			  Abramo Bagnara <abramo@alsa-project.org>
+ *
+ *
+ *   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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include "pcm_plugin.h"
+
+/*
+ *  Basic linear conversion plugin
+ */
+ 
+struct linear_priv {
+	int cvt_endian;		/* need endian conversion? */
+	unsigned int src_ofs;	/* byte offset in source format */
+	unsigned int dst_ofs;	/* byte soffset in destination format */
+	unsigned int copy_ofs;	/* byte offset in temporary u32 data */
+	unsigned int dst_bytes;		/* byte size of destination format */
+	unsigned int copy_bytes;	/* bytes to copy per conversion */
+	unsigned int flip; /* MSB flip for signeness, done after endian conv */
+};
+
+static inline void do_convert(struct linear_priv *data,
+			      unsigned char *dst, unsigned char *src)
+{
+	unsigned int tmp = 0;
+	unsigned char *p = (unsigned char *)&tmp;
+
+	memcpy(p + data->copy_ofs, src + data->src_ofs, data->copy_bytes);
+	if (data->cvt_endian)
+		tmp = swab32(tmp);
+	tmp ^= data->flip;
+	memcpy(dst, p + data->dst_ofs, data->dst_bytes);
+}
+
+static void convert(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)
+{
+	struct linear_priv *data = (struct linear_priv *)plugin->extra_data;
+	int channel;
+	int nchannels = plugin->src_format.channels;
+	for (channel = 0; channel < nchannels; ++channel) {
+		char *src;
+		char *dst;
+		int src_step, dst_step;
+		snd_pcm_uframes_t frames1;
+		if (!src_channels[channel].enabled) {
+			if (dst_channels[channel].wanted)
+				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
+			dst_channels[channel].enabled = 0;
+			continue;
+		}
+		dst_channels[channel].enabled = 1;
+		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
+		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
+		src_step = src_channels[channel].area.step / 8;
+		dst_step = dst_channels[channel].area.step / 8;
+		frames1 = frames;
+		while (frames1-- > 0) {
+			do_convert(data, dst, src);
+			src += src_step;
+			dst += dst_step;
+		}
+	}
+}
+
+static snd_pcm_sframes_t linear_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)
+{
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+#ifdef CONFIG_SND_DEBUG
+	{
+		unsigned int channel;
+		for (channel = 0; channel < plugin->src_format.channels; channel++) {
+			if (snd_BUG_ON(src_channels[channel].area.first % 8 ||
+				       src_channels[channel].area.step % 8))
+				return -ENXIO;
+			if (snd_BUG_ON(dst_channels[channel].area.first % 8 ||
+				       dst_channels[channel].area.step % 8))
+				return -ENXIO;
+		}
+	}
+#endif
+	convert(plugin, src_channels, dst_channels, frames);
+	return frames;
+}
+
+static void init_data(struct linear_priv *data,
+		      snd_pcm_format_t src_format, snd_pcm_format_t dst_format)
+{
+	int src_le, dst_le, src_bytes, dst_bytes;
+
+	src_bytes = snd_pcm_format_width(src_format) / 8;
+	dst_bytes = snd_pcm_format_width(dst_format) / 8;
+	src_le = snd_pcm_format_little_endian(src_format) > 0;
+	dst_le = snd_pcm_format_little_endian(dst_format) > 0;
+
+	data->dst_bytes = dst_bytes;
+	data->cvt_endian = src_le != dst_le;
+	data->copy_bytes = src_bytes < dst_bytes ? src_bytes : dst_bytes;
+	if (src_le) {
+		data->copy_ofs = 4 - data->copy_bytes;
+		data->src_ofs = src_bytes - data->copy_bytes;
+	} else
+		data->src_ofs = snd_pcm_format_physical_width(src_format) / 8 -
+			src_bytes;
+	if (dst_le)
+		data->dst_ofs = 4 - data->dst_bytes;
+	else
+		data->dst_ofs = snd_pcm_format_physical_width(dst_format) / 8 -
+			dst_bytes;
+	if (snd_pcm_format_signed(src_format) !=
+	    snd_pcm_format_signed(dst_format)) {
+		if (dst_le)
+			data->flip = (__force u32)cpu_to_le32(0x80000000);
+		else
+			data->flip = (__force u32)cpu_to_be32(0x80000000);
+	}
+}
+
+int snd_pcm_plugin_build_linear(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 linear_priv *data;
+	struct snd_pcm_plugin *plugin;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+
+	if (snd_BUG_ON(src_format->rate != dst_format->rate))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->channels != dst_format->channels))
+		return -ENXIO;
+	if (snd_BUG_ON(!snd_pcm_format_linear(src_format->format) ||
+		       !snd_pcm_format_linear(dst_format->format)))
+		return -ENXIO;
+
+	err = snd_pcm_plugin_build(plug, "linear format conversion",
+				   src_format, dst_format,
+				   sizeof(struct linear_priv), &plugin);
+	if (err < 0)
+		return err;
+	data = (struct linear_priv *)plugin->extra_data;
+	init_data(data, src_format->format, dst_format->format);
+	plugin->transfer = linear_transfer;
+	*r_plugin = plugin;
+	return 0;
+}

sound/core/oss/mulaw.c

@@ -0,0 +1,344 @@
+/*
+ *  Mu-Law conversion Plug-In Interface
+ *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
+ *                        Uros Bizjak <uros@kss-loka.si>
+ *
+ *  Based on reference implementation by Sun Microsystems, Inc.
+ *
+ *   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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include "pcm_plugin.h"
+
+#define	SIGN_BIT	(0x80)		/* Sign bit for a u-law byte. */
+#define	QUANT_MASK	(0xf)		/* Quantization field mask. */
+#define	NSEGS		(8)		/* Number of u-law segments. */
+#define	SEG_SHIFT	(4)		/* Left shift for segment number. */
+#define	SEG_MASK	(0x70)		/* Segment field mask. */
+
+static inline int val_seg(int val)
+{
+	int r = 0;
+	val >>= 7;
+	if (val & 0xf0) {
+		val >>= 4;
+		r += 4;
+	}
+	if (val & 0x0c) {
+		val >>= 2;
+		r += 2;
+	}
+	if (val & 0x02)
+		r += 1;
+	return r;
+}
+
+#define	BIAS		(0x84)		/* Bias for linear code. */
+
+/*
+ * linear2ulaw() - Convert a linear PCM value to u-law
+ *
+ * In order to simplify the encoding process, the original linear magnitude
+ * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
+ * (33 - 8191). The result can be seen in the following encoding table:
+ *
+ *	Biased Linear Input Code	Compressed Code
+ *	------------------------	---------------
+ *	00000001wxyza			000wxyz
+ *	0000001wxyzab			001wxyz
+ *	000001wxyzabc			010wxyz
+ *	00001wxyzabcd			011wxyz
+ *	0001wxyzabcde			100wxyz
+ *	001wxyzabcdef			101wxyz
+ *	01wxyzabcdefg			110wxyz
+ *	1wxyzabcdefgh			111wxyz
+ *
+ * Each biased linear code has a leading 1 which identifies the segment
+ * number. The value of the segment number is equal to 7 minus the number
+ * of leading 0's. The quantization interval is directly available as the
+ * four bits wxyz.  * The trailing bits (a - h) are ignored.
+ *
+ * Ordinarily the complement of the resulting code word is used for
+ * transmission, and so the code word is complemented before it is returned.
+ *
+ * For further information see John C. Bellamy's Digital Telephony, 1982,
+ * John Wiley & Sons, pps 98-111 and 472-476.
+ */
+static unsigned char linear2ulaw(int pcm_val)	/* 2's complement (16-bit range) */
+{
+	int mask;
+	int seg;
+	unsigned char uval;
+
+	/* Get the sign and the magnitude of the value. */
+	if (pcm_val < 0) {
+		pcm_val = BIAS - pcm_val;
+		mask = 0x7F;
+	} else {
+		pcm_val += BIAS;
+		mask = 0xFF;
+	}
+	if (pcm_val > 0x7FFF)
+		pcm_val = 0x7FFF;
+
+	/* Convert the scaled magnitude to segment number. */
+	seg = val_seg(pcm_val);
+
+	/*
+	 * Combine the sign, segment, quantization bits;
+	 * and complement the code word.
+	 */
+	uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF);
+	return uval ^ mask;
+}
+
+/*
+ * ulaw2linear() - Convert a u-law value to 16-bit linear PCM
+ *
+ * First, a biased linear code is derived from the code word. An unbiased
+ * output can then be obtained by subtracting 33 from the biased code.
+ *
+ * Note that this function expects to be passed the complement of the
+ * original code word. This is in keeping with ISDN conventions.
+ */
+static int ulaw2linear(unsigned char u_val)
+{
+	int t;
+
+	/* Complement to obtain normal u-law value. */
+	u_val = ~u_val;
+
+	/*
+	 * Extract and bias the quantization bits. Then
+	 * shift up by the segment number and subtract out the bias.
+	 */
+	t = ((u_val & QUANT_MASK) << 3) + BIAS;
+	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
+
+	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
+}
+
+/*
+ *  Basic Mu-Law plugin
+ */
+
+typedef void (*mulaw_f)(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);
+
+struct mulaw_priv {
+	mulaw_f func;
+	int cvt_endian;			/* need endian conversion? */
+	unsigned int native_ofs;	/* byte offset in native format */
+	unsigned int copy_ofs;		/* byte offset in s16 format */
+	unsigned int native_bytes;	/* byte size of the native format */
+	unsigned int copy_bytes;	/* bytes to copy per conversion */
+	u16 flip; /* MSB flip for signedness, done after endian conversion */
+};
+
+static inline void cvt_s16_to_native(struct mulaw_priv *data,
+				     unsigned char *dst, u16 sample)
+{
+	sample ^= data->flip;
+	if (data->cvt_endian)
+		sample = swab16(sample);
+	if (data->native_bytes > data->copy_bytes)
+		memset(dst, 0, data->native_bytes);
+	memcpy(dst + data->native_ofs, (char *)&sample + data->copy_ofs,
+	       data->copy_bytes);
+}
+
+static void mulaw_decode(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)
+{
+	struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
+	int channel;
+	int nchannels = plugin->src_format.channels;
+	for (channel = 0; channel < nchannels; ++channel) {
+		char *src;
+		char *dst;
+		int src_step, dst_step;
+		snd_pcm_uframes_t frames1;
+		if (!src_channels[channel].enabled) {
+			if (dst_channels[channel].wanted)
+				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
+			dst_channels[channel].enabled = 0;
+			continue;
+		}
+		dst_channels[channel].enabled = 1;
+		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
+		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
+		src_step = src_channels[channel].area.step / 8;
+		dst_step = dst_channels[channel].area.step / 8;
+		frames1 = frames;
+		while (frames1-- > 0) {
+			signed short sample = ulaw2linear(*src);
+			cvt_s16_to_native(data, dst, sample);
+			src += src_step;
+			dst += dst_step;
+		}
+	}
+}
+
+static inline signed short cvt_native_to_s16(struct mulaw_priv *data,
+					     unsigned char *src)
+{
+	u16 sample = 0;
+	memcpy((char *)&sample + data->copy_ofs, src + data->native_ofs,
+	       data->copy_bytes);
+	if (data->cvt_endian)
+		sample = swab16(sample);
+	sample ^= data->flip;
+	return (signed short)sample;
+}
+
+static void mulaw_encode(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)
+{
+	struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
+	int channel;
+	int nchannels = plugin->src_format.channels;
+	for (channel = 0; channel < nchannels; ++channel) {
+		char *src;
+		char *dst;
+		int src_step, dst_step;
+		snd_pcm_uframes_t frames1;
+		if (!src_channels[channel].enabled) {
+			if (dst_channels[channel].wanted)
+				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
+			dst_channels[channel].enabled = 0;
+			continue;
+		}
+		dst_channels[channel].enabled = 1;
+		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
+		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
+		src_step = src_channels[channel].area.step / 8;
+		dst_step = dst_channels[channel].area.step / 8;
+		frames1 = frames;
+		while (frames1-- > 0) {
+			signed short sample = cvt_native_to_s16(data, src);
+			*dst = linear2ulaw(sample);
+			src += src_step;
+			dst += dst_step;
+		}
+	}
+}
+
+static snd_pcm_sframes_t mulaw_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)
+{
+	struct mulaw_priv *data;
+
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+#ifdef CONFIG_SND_DEBUG
+	{
+		unsigned int channel;
+		for (channel = 0; channel < plugin->src_format.channels; channel++) {
+			if (snd_BUG_ON(src_channels[channel].area.first % 8 ||
+				       src_channels[channel].area.step % 8))
+				return -ENXIO;
+			if (snd_BUG_ON(dst_channels[channel].area.first % 8 ||
+				       dst_channels[channel].area.step % 8))
+				return -ENXIO;
+		}
+	}
+#endif
+	data = (struct mulaw_priv *)plugin->extra_data;
+	data->func(plugin, src_channels, dst_channels, frames);
+	return frames;
+}
+
+static void init_data(struct mulaw_priv *data, snd_pcm_format_t format)
+{
+#ifdef SNDRV_LITTLE_ENDIAN
+	data->cvt_endian = snd_pcm_format_big_endian(format) > 0;
+#else
+	data->cvt_endian = snd_pcm_format_little_endian(format) > 0;
+#endif
+	if (!snd_pcm_format_signed(format))
+		data->flip = 0x8000;
+	data->native_bytes = snd_pcm_format_physical_width(format) / 8;
+	data->copy_bytes = data->native_bytes < 2 ? 1 : 2;
+	if (snd_pcm_format_little_endian(format)) {
+		data->native_ofs = data->native_bytes - data->copy_bytes;
+		data->copy_ofs = 2 - data->copy_bytes;
+	} else {
+		/* S24 in 4bytes need an 1 byte offset */
+		data->native_ofs = data->native_bytes -
+			snd_pcm_format_width(format) / 8;
+	}
+}
+
+int snd_pcm_plugin_build_mulaw(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 mulaw_priv *data;
+	struct snd_pcm_plugin *plugin;
+	struct snd_pcm_plugin_format *format;
+	mulaw_f func;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+
+	if (snd_BUG_ON(src_format->rate != dst_format->rate))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->channels != dst_format->channels))
+		return -ENXIO;
+
+	if (dst_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
+		format = src_format;
+		func = mulaw_encode;
+	}
+	else if (src_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
+		format = dst_format;
+		func = mulaw_decode;
+	}
+	else {
+		snd_BUG();
+		return -EINVAL;
+	}
+	if (snd_BUG_ON(!snd_pcm_format_linear(format->format)))
+		return -ENXIO;
+
+	err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion",
+				   src_format, dst_format,
+				   sizeof(struct mulaw_priv), &plugin);
+	if (err < 0)
+		return err;
+	data = (struct mulaw_priv *)plugin->extra_data;
+	data->func = func;
+	init_data(data, format->format);
+	plugin->transfer = mulaw_transfer;
+	*r_plugin = plugin;
+	return 0;
+}

sound/core/oss/pcm_plugin.c

@@ -0,0 +1,758 @@
+/*
+ *  PCM Plug-In shared (kernel/library) code
+ *  Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
+ *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
+ *
+ *
+ *   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
+ *
+ */
+  
+#if 0
+#define PLUGIN_DEBUG
+#endif
+
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/vmalloc.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include "pcm_plugin.h"
+
+#define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
+#define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
+
+/*
+ *  because some cards might have rates "very close", we ignore
+ *  all "resampling" requests within +-5%
+ */
+static int rate_match(unsigned int src_rate, unsigned int dst_rate)
+{
+	unsigned int low = (src_rate * 95) / 100;
+	unsigned int high = (src_rate * 105) / 100;
+	return dst_rate >= low && dst_rate <= high;
+}
+
+static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
+{
+	struct snd_pcm_plugin_format *format;
+	ssize_t width;
+	size_t size;
+	unsigned int channel;
+	struct snd_pcm_plugin_channel *c;
+
+	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		format = &plugin->src_format;
+	} else {
+		format = &plugin->dst_format;
+	}
+	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
+		return width;
+	size = frames * format->channels * width;
+	if (snd_BUG_ON(size % 8))
+		return -ENXIO;
+	size /= 8;
+	if (plugin->buf_frames < frames) {
+		vfree(plugin->buf);
+		plugin->buf = vmalloc(size);
+		plugin->buf_frames = frames;
+	}
+	if (!plugin->buf) {
+		plugin->buf_frames = 0;
+		return -ENOMEM;
+	}
+	c = plugin->buf_channels;
+	if (plugin->access == SNDRV_PCM_ACCESS_RW_INTERLEAVED) {
+		for (channel = 0; channel < format->channels; channel++, c++) {
+			c->frames = frames;
+			c->enabled = 1;
+			c->wanted = 0;
+			c->area.addr = plugin->buf;
+			c->area.first = channel * width;
+			c->area.step = format->channels * width;
+		}
+	} else if (plugin->access == SNDRV_PCM_ACCESS_RW_NONINTERLEAVED) {
+		if (snd_BUG_ON(size % format->channels))
+			return -EINVAL;
+		size /= format->channels;
+		for (channel = 0; channel < format->channels; channel++, c++) {
+			c->frames = frames;
+			c->enabled = 1;
+			c->wanted = 0;
+			c->area.addr = plugin->buf + (channel * size);
+			c->area.first = 0;
+			c->area.step = width;
+		}
+	} else
+		return -EINVAL;
+	return 0;
+}
+
+int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames)
+{
+	int err;
+	if (snd_BUG_ON(!snd_pcm_plug_first(plug)))
+		return -ENXIO;
+	if (snd_pcm_plug_stream(plug) == SNDRV_PCM_STREAM_PLAYBACK) {
+		struct snd_pcm_plugin *plugin = snd_pcm_plug_first(plug);
+		while (plugin->next) {
+			if (plugin->dst_frames)
+				frames = plugin->dst_frames(plugin, frames);
+			if (snd_BUG_ON(frames <= 0))
+				return -ENXIO;
+			plugin = plugin->next;
+			err = snd_pcm_plugin_alloc(plugin, frames);
+			if (err < 0)
+				return err;
+		}
+	} else {
+		struct snd_pcm_plugin *plugin = snd_pcm_plug_last(plug);
+		while (plugin->prev) {
+			if (plugin->src_frames)
+				frames = plugin->src_frames(plugin, frames);
+			if (snd_BUG_ON(frames <= 0))
+				return -ENXIO;
+			plugin = plugin->prev;
+			err = snd_pcm_plugin_alloc(plugin, frames);
+			if (err < 0)
+				return err;
+		}
+	}
+	return 0;
+}
+
+
+snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
+				       snd_pcm_uframes_t frames,
+				       struct snd_pcm_plugin_channel **channels)
+{
+	*channels = plugin->buf_channels;
+	return frames;
+}
+
+int snd_pcm_plugin_build(struct snd_pcm_substream *plug,
+			 const char *name,
+			 struct snd_pcm_plugin_format *src_format,
+			 struct snd_pcm_plugin_format *dst_format,
+			 size_t extra,
+			 struct snd_pcm_plugin **ret)
+{
+	struct snd_pcm_plugin *plugin;
+	unsigned int channels;
+	
+	if (snd_BUG_ON(!plug))
+		return -ENXIO;
+	if (snd_BUG_ON(!src_format || !dst_format))
+		return -ENXIO;
+	plugin = kzalloc(sizeof(*plugin) + extra, GFP_KERNEL);
+	if (plugin == NULL)
+		return -ENOMEM;
+	plugin->name = name;
+	plugin->plug = plug;
+	plugin->stream = snd_pcm_plug_stream(plug);
+	plugin->access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
+	plugin->src_format = *src_format;
+	plugin->src_width = snd_pcm_format_physical_width(src_format->format);
+	snd_BUG_ON(plugin->src_width <= 0);
+	plugin->dst_format = *dst_format;
+	plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
+	snd_BUG_ON(plugin->dst_width <= 0);
+	if (plugin->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		channels = src_format->channels;
+	else
+		channels = dst_format->channels;
+	plugin->buf_channels = kcalloc(channels, sizeof(*plugin->buf_channels), GFP_KERNEL);
+	if (plugin->buf_channels == NULL) {
+		snd_pcm_plugin_free(plugin);
+		return -ENOMEM;
+	}
+	plugin->client_channels = snd_pcm_plugin_client_channels;
+	*ret = plugin;
+	return 0;
+}
+
+int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin)
+{
+	if (! plugin)
+		return 0;
+	if (plugin->private_free)
+		plugin->private_free(plugin);
+	kfree(plugin->buf_channels);
+	vfree(plugin->buf);
+	kfree(plugin);
+	return 0;
+}
+
+snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t drv_frames)
+{
+	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
+	int stream;
+
+	if (snd_BUG_ON(!plug))
+		return -ENXIO;
+	if (drv_frames == 0)
+		return 0;
+	stream = snd_pcm_plug_stream(plug);
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		plugin = snd_pcm_plug_last(plug);
+		while (plugin && drv_frames > 0) {
+			plugin_prev = plugin->prev;
+			if (plugin->src_frames)
+				drv_frames = plugin->src_frames(plugin, drv_frames);
+			plugin = plugin_prev;
+		}
+	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
+		plugin = snd_pcm_plug_first(plug);
+		while (plugin && drv_frames > 0) {
+			plugin_next = plugin->next;
+			if (plugin->dst_frames)
+				drv_frames = plugin->dst_frames(plugin, drv_frames);
+			plugin = plugin_next;
+		}
+	} else
+		snd_BUG();
+	return drv_frames;
+}
+
+snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *plug, snd_pcm_uframes_t clt_frames)
+{
+	struct snd_pcm_plugin *plugin, *plugin_prev, *plugin_next;
+	snd_pcm_sframes_t frames;
+	int stream;
+	
+	if (snd_BUG_ON(!plug))
+		return -ENXIO;
+	if (clt_frames == 0)
+		return 0;
+	frames = clt_frames;
+	stream = snd_pcm_plug_stream(plug);
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		plugin = snd_pcm_plug_first(plug);
+		while (plugin && frames > 0) {
+			plugin_next = plugin->next;
+			if (plugin->dst_frames) {
+				frames = plugin->dst_frames(plugin, frames);
+				if (frames < 0)
+					return frames;
+			}
+			plugin = plugin_next;
+		}
+	} else if (stream == SNDRV_PCM_STREAM_CAPTURE) {
+		plugin = snd_pcm_plug_last(plug);
+		while (plugin) {
+			plugin_prev = plugin->prev;
+			if (plugin->src_frames) {
+				frames = plugin->src_frames(plugin, frames);
+				if (frames < 0)
+					return frames;
+			}
+			plugin = plugin_prev;
+		}
+	} else
+		snd_BUG();
+	return frames;
+}
+
+static int snd_pcm_plug_formats(struct snd_mask *mask, snd_pcm_format_t format)
+{
+	struct snd_mask formats = *mask;
+	u64 linfmts = (SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S8 |
+		       SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_S16_LE |
+		       SNDRV_PCM_FMTBIT_U16_BE | SNDRV_PCM_FMTBIT_S16_BE |
+		       SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_S24_LE |
+		       SNDRV_PCM_FMTBIT_U24_BE | SNDRV_PCM_FMTBIT_S24_BE |
+		       SNDRV_PCM_FMTBIT_U24_3LE | SNDRV_PCM_FMTBIT_S24_3LE |
+		       SNDRV_PCM_FMTBIT_U24_3BE | SNDRV_PCM_FMTBIT_S24_3BE |
+		       SNDRV_PCM_FMTBIT_U32_LE | SNDRV_PCM_FMTBIT_S32_LE |
+		       SNDRV_PCM_FMTBIT_U32_BE | SNDRV_PCM_FMTBIT_S32_BE);
+	snd_mask_set(&formats, (__force int)SNDRV_PCM_FORMAT_MU_LAW);
+	
+	if (formats.bits[0] & (u32)linfmts)
+		formats.bits[0] |= (u32)linfmts;
+	if (formats.bits[1] & (u32)(linfmts >> 32))
+		formats.bits[1] |= (u32)(linfmts >> 32);
+	return snd_mask_test(&formats, (__force int)format);
+}
+
+static snd_pcm_format_t preferred_formats[] = {
+	SNDRV_PCM_FORMAT_S16_LE,
+	SNDRV_PCM_FORMAT_S16_BE,
+	SNDRV_PCM_FORMAT_U16_LE,
+	SNDRV_PCM_FORMAT_U16_BE,
+	SNDRV_PCM_FORMAT_S24_3LE,
+	SNDRV_PCM_FORMAT_S24_3BE,
+	SNDRV_PCM_FORMAT_U24_3LE,
+	SNDRV_PCM_FORMAT_U24_3BE,
+	SNDRV_PCM_FORMAT_S24_LE,
+	SNDRV_PCM_FORMAT_S24_BE,
+	SNDRV_PCM_FORMAT_U24_LE,
+	SNDRV_PCM_FORMAT_U24_BE,
+	SNDRV_PCM_FORMAT_S32_LE,
+	SNDRV_PCM_FORMAT_S32_BE,
+	SNDRV_PCM_FORMAT_U32_LE,
+	SNDRV_PCM_FORMAT_U32_BE,
+	SNDRV_PCM_FORMAT_S8,
+	SNDRV_PCM_FORMAT_U8
+};
+
+snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format,
+					   struct snd_mask *format_mask)
+{
+	int i;
+
+	if (snd_mask_test(format_mask, (__force int)format))
+		return format;
+	if (!snd_pcm_plug_formats(format_mask, format))
+		return (__force snd_pcm_format_t)-EINVAL;
+	if (snd_pcm_format_linear(format)) {
+		unsigned int width = snd_pcm_format_width(format);
+		int unsignd = snd_pcm_format_unsigned(format) > 0;
+		int big = snd_pcm_format_big_endian(format) > 0;
+		unsigned int badness, best = -1;
+		snd_pcm_format_t best_format = (__force snd_pcm_format_t)-1;
+		for (i = 0; i < ARRAY_SIZE(preferred_formats); i++) {
+			snd_pcm_format_t f = preferred_formats[i];
+			unsigned int w;
+			if (!snd_mask_test(format_mask, (__force int)f))
+				continue;
+			w = snd_pcm_format_width(f);
+			if (w >= width)
+				badness = w - width;
+			else
+				badness = width - w + 32;
+			badness += snd_pcm_format_unsigned(f) != unsignd;
+			badness += snd_pcm_format_big_endian(f) != big;
+			if (badness < best) {
+				best_format = f;
+				best = badness;
+			}
+		}
+		if ((__force int)best_format >= 0)
+			return best_format;
+		else
+			return (__force snd_pcm_format_t)-EINVAL;
+	} else {
+		switch (format) {
+		case SNDRV_PCM_FORMAT_MU_LAW:
+			for (i = 0; i < ARRAY_SIZE(preferred_formats); ++i) {
+				snd_pcm_format_t format1 = preferred_formats[i];
+				if (snd_mask_test(format_mask, (__force int)format1))
+					return format1;
+			}
+		default:
+			return (__force snd_pcm_format_t)-EINVAL;
+		}
+	}
+}
+
+int snd_pcm_plug_format_plugins(struct snd_pcm_substream *plug,
+				struct snd_pcm_hw_params *params,
+				struct snd_pcm_hw_params *slave_params)
+{
+	struct snd_pcm_plugin_format tmpformat;
+	struct snd_pcm_plugin_format dstformat;
+	struct snd_pcm_plugin_format srcformat;
+	snd_pcm_access_t src_access, dst_access;
+	struct snd_pcm_plugin *plugin = NULL;
+	int err;
+	int stream = snd_pcm_plug_stream(plug);
+	int slave_interleaved = (params_channels(slave_params) == 1 ||
+				 params_access(slave_params) == SNDRV_PCM_ACCESS_RW_INTERLEAVED);
+
+	switch (stream) {
+	case SNDRV_PCM_STREAM_PLAYBACK:
+		dstformat.format = params_format(slave_params);
+		dstformat.rate = params_rate(slave_params);
+		dstformat.channels = params_channels(slave_params);
+		srcformat.format = params_format(params);
+		srcformat.rate = params_rate(params);
+		srcformat.channels = params_channels(params);
+		src_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
+		dst_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
+						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
+		break;
+	case SNDRV_PCM_STREAM_CAPTURE:
+		dstformat.format = params_format(params);
+		dstformat.rate = params_rate(params);
+		dstformat.channels = params_channels(params);
+		srcformat.format = params_format(slave_params);
+		srcformat.rate = params_rate(slave_params);
+		srcformat.channels = params_channels(slave_params);
+		src_access = (slave_interleaved ? SNDRV_PCM_ACCESS_RW_INTERLEAVED :
+						  SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
+		dst_access = SNDRV_PCM_ACCESS_RW_INTERLEAVED;
+		break;
+	default:
+		snd_BUG();
+		return -EINVAL;
+	}
+	tmpformat = srcformat;
+		
+	pdprintf("srcformat: format=%i, rate=%i, channels=%i\n", 
+		 srcformat.format,
+		 srcformat.rate,
+		 srcformat.channels);
+	pdprintf("dstformat: format=%i, rate=%i, channels=%i\n", 
+		 dstformat.format,
+		 dstformat.rate,
+		 dstformat.channels);
+
+	/* Format change (linearization) */
+	if (! rate_match(srcformat.rate, dstformat.rate) &&
+	    ! snd_pcm_format_linear(srcformat.format)) {
+		if (srcformat.format != SNDRV_PCM_FORMAT_MU_LAW)
+			return -EINVAL;
+		tmpformat.format = SNDRV_PCM_FORMAT_S16;
+		err = snd_pcm_plugin_build_mulaw(plug,
+						 &srcformat, &tmpformat,
+						 &plugin);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+		srcformat = tmpformat;
+		src_access = dst_access;
+	}
+
+	/* channels reduction */
+	if (srcformat.channels > dstformat.channels) {
+		tmpformat.channels = dstformat.channels;
+		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
+		pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+		srcformat = tmpformat;
+		src_access = dst_access;
+	}
+
+	/* rate resampling */
+	if (!rate_match(srcformat.rate, dstformat.rate)) {
+		if (srcformat.format != SNDRV_PCM_FORMAT_S16) {
+			/* convert to S16 for resampling */
+			tmpformat.format = SNDRV_PCM_FORMAT_S16;
+			err = snd_pcm_plugin_build_linear(plug,
+							  &srcformat, &tmpformat,
+							  &plugin);
+			if (err < 0)
+				return err;
+			err = snd_pcm_plugin_append(plugin);
+			if (err < 0) {
+				snd_pcm_plugin_free(plugin);
+				return err;
+			}
+			srcformat = tmpformat;
+			src_access = dst_access;
+		}
+		tmpformat.rate = dstformat.rate;
+        	err = snd_pcm_plugin_build_rate(plug,
+        					&srcformat, &tmpformat,
+						&plugin);
+		pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat.rate, tmpformat.rate, err);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+		srcformat = tmpformat;
+		src_access = dst_access;
+        }
+
+	/* format change */
+	if (srcformat.format != dstformat.format) {
+		tmpformat.format = dstformat.format;
+		if (srcformat.format == SNDRV_PCM_FORMAT_MU_LAW ||
+		    tmpformat.format == SNDRV_PCM_FORMAT_MU_LAW) {
+			err = snd_pcm_plugin_build_mulaw(plug,
+							 &srcformat, &tmpformat,
+							 &plugin);
+		}
+		else if (snd_pcm_format_linear(srcformat.format) &&
+			 snd_pcm_format_linear(tmpformat.format)) {
+			err = snd_pcm_plugin_build_linear(plug,
+							  &srcformat, &tmpformat,
+							  &plugin);
+		}
+		else
+			return -EINVAL;
+		pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat.format, tmpformat.format, err);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+		srcformat = tmpformat;
+		src_access = dst_access;
+	}
+
+	/* channels extension */
+	if (srcformat.channels < dstformat.channels) {
+		tmpformat.channels = dstformat.channels;
+		err = snd_pcm_plugin_build_route(plug, &srcformat, &tmpformat, &plugin);
+		pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat.channels, tmpformat.channels, err);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+		srcformat = tmpformat;
+		src_access = dst_access;
+	}
+
+	/* de-interleave */
+	if (src_access != dst_access) {
+		err = snd_pcm_plugin_build_copy(plug,
+						&srcformat,
+						&tmpformat,
+						&plugin);
+		pdprintf("interleave change (copy: returns %i)\n", err);
+		if (err < 0)
+			return err;
+		err = snd_pcm_plugin_append(plugin);
+		if (err < 0) {
+			snd_pcm_plugin_free(plugin);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *plug,
+					 char *buf,
+					 snd_pcm_uframes_t count,
+					 struct snd_pcm_plugin_channel **channels)
+{
+	struct snd_pcm_plugin *plugin;
+	struct snd_pcm_plugin_channel *v;
+	struct snd_pcm_plugin_format *format;
+	int width, nchannels, channel;
+	int stream = snd_pcm_plug_stream(plug);
+
+	if (snd_BUG_ON(!buf))
+		return -ENXIO;
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		plugin = snd_pcm_plug_first(plug);
+		format = &plugin->src_format;
+	} else {
+		plugin = snd_pcm_plug_last(plug);
+		format = &plugin->dst_format;
+	}
+	v = plugin->buf_channels;
+	*channels = v;
+	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
+		return width;
+	nchannels = format->channels;
+	if (snd_BUG_ON(plugin->access != SNDRV_PCM_ACCESS_RW_INTERLEAVED &&
+		       format->channels > 1))
+		return -ENXIO;
+	for (channel = 0; channel < nchannels; channel++, v++) {
+		v->frames = count;
+		v->enabled = 1;
+		v->wanted = (stream == SNDRV_PCM_STREAM_CAPTURE);
+		v->area.addr = buf;
+		v->area.first = channel * width;
+		v->area.step = nchannels * width;
+	}
+	return count;
+}
+
+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)
+{
+	struct snd_pcm_plugin *plugin, *next;
+	struct snd_pcm_plugin_channel *dst_channels;
+	int err;
+	snd_pcm_sframes_t frames = size;
+
+	plugin = snd_pcm_plug_first(plug);
+	while (plugin && frames > 0) {
+		if ((next = plugin->next) != NULL) {
+			snd_pcm_sframes_t frames1 = frames;
+			if (plugin->dst_frames)
+				frames1 = plugin->dst_frames(plugin, frames);
+			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
+				return err;
+			}
+			if (err != frames1) {
+				frames = err;
+				if (plugin->src_frames)
+					frames = plugin->src_frames(plugin, frames1);
+			}
+		} else
+			dst_channels = NULL;
+		pdprintf("write plugin: %s, %li\n", plugin->name, frames);
+		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
+			return frames;
+		src_channels = dst_channels;
+		plugin = next;
+	}
+	return snd_pcm_plug_client_size(plug, frames);
+}
+
+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)
+{
+	struct snd_pcm_plugin *plugin, *next;
+	struct snd_pcm_plugin_channel *src_channels, *dst_channels;
+	snd_pcm_sframes_t frames = size;
+	int err;
+
+	frames = snd_pcm_plug_slave_size(plug, frames);
+	if (frames < 0)
+		return frames;
+
+	src_channels = NULL;
+	plugin = snd_pcm_plug_first(plug);
+	while (plugin && frames > 0) {
+		if ((next = plugin->next) != NULL) {
+			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
+				return err;
+			}
+			frames = err;
+		} else {
+			dst_channels = dst_channels_final;
+		}
+		pdprintf("read plugin: %s, %li\n", plugin->name, frames);
+		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
+			return frames;
+		plugin = next;
+		src_channels = dst_channels;
+	}
+	return frames;
+}
+
+int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
+			 size_t samples, snd_pcm_format_t format)
+{
+	/* FIXME: sub byte resolution and odd dst_offset */
+	unsigned char *dst;
+	unsigned int dst_step;
+	int width;
+	const unsigned char *silence;
+	if (!dst_area->addr)
+		return 0;
+	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
+	width = snd_pcm_format_physical_width(format);
+	if (width <= 0)
+		return -EINVAL;
+	if (dst_area->step == (unsigned int) width && width >= 8)
+		return snd_pcm_format_set_silence(format, dst, samples);
+	silence = snd_pcm_format_silence_64(format);
+	if (! silence)
+		return -EINVAL;
+	dst_step = dst_area->step / 8;
+	if (width == 4) {
+		/* Ima ADPCM */
+		int dstbit = dst_area->first % 8;
+		int dstbit_step = dst_area->step % 8;
+		while (samples-- > 0) {
+			if (dstbit)
+				*dst &= 0xf0;
+			else
+				*dst &= 0x0f;
+			dst += dst_step;
+			dstbit += dstbit_step;
+			if (dstbit == 8) {
+				dst++;
+				dstbit = 0;
+			}
+		}
+	} else {
+		width /= 8;
+		while (samples-- > 0) {
+			memcpy(dst, silence, width);
+			dst += dst_step;
+		}
+	}
+	return 0;
+}
+
+int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_area, size_t src_offset,
+		      const struct snd_pcm_channel_area *dst_area, size_t dst_offset,
+		      size_t samples, snd_pcm_format_t format)
+{
+	/* FIXME: sub byte resolution and odd dst_offset */
+	char *src, *dst;
+	int width;
+	int src_step, dst_step;
+	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
+	if (!src_area->addr)
+		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
+	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
+	if (!dst_area->addr)
+		return 0;
+	width = snd_pcm_format_physical_width(format);
+	if (width <= 0)
+		return -EINVAL;
+	if (src_area->step == (unsigned int) width &&
+	    dst_area->step == (unsigned int) width && width >= 8) {
+		size_t bytes = samples * width / 8;
+		memcpy(dst, src, bytes);
+		return 0;
+	}
+	src_step = src_area->step / 8;
+	dst_step = dst_area->step / 8;
+	if (width == 4) {
+		/* Ima ADPCM */
+		int srcbit = src_area->first % 8;
+		int srcbit_step = src_area->step % 8;
+		int dstbit = dst_area->first % 8;
+		int dstbit_step = dst_area->step % 8;
+		while (samples-- > 0) {
+			unsigned char srcval;
+			if (srcbit)
+				srcval = *src & 0x0f;
+			else
+				srcval = (*src & 0xf0) >> 4;
+			if (dstbit)
+				*dst = (*dst & 0xf0) | srcval;
+			else
+				*dst = (*dst & 0x0f) | (srcval << 4);
+			src += src_step;
+			srcbit += srcbit_step;
+			if (srcbit == 8) {
+				src++;
+				srcbit = 0;
+			}
+			dst += dst_step;
+			dstbit += dstbit_step;
+			if (dstbit == 8) {
+				dst++;
+				dstbit = 0;
+			}
+		}
+	} else {
+		width /= 8;
+		while (samples-- > 0) {
+			memcpy(dst, src, width);
+			src += src_step;
+			dst += dst_step;
+		}
+	}
+	return 0;
+}

sound/core/oss/pcm_plugin.h

@@ -0,0 +1,185 @@
+#ifndef __PCM_PLUGIN_H
+#define __PCM_PLUGIN_H
+
+/*
+ *  Digital Audio (Plugin interface) abstract layer
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ *
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ *
+ */
+
+#ifdef CONFIG_SND_PCM_OSS_PLUGINS
+
+#define snd_pcm_plug_stream(plug) ((plug)->stream)
+
+enum snd_pcm_plugin_action {
+	INIT = 0,
+	PREPARE = 1,
+};
+
+struct snd_pcm_channel_area {
+	void *addr;			/* base address of channel samples */
+	unsigned int first;		/* offset to first sample in bits */
+	unsigned int step;		/* samples distance in bits */
+};
+
+struct snd_pcm_plugin_channel {
+	void *aptr;			/* pointer to the allocated area */
+	struct snd_pcm_channel_area area;
+	snd_pcm_uframes_t frames;	/* allocated frames */
+	unsigned int enabled:1;		/* channel need to be processed */
+	unsigned int wanted:1;		/* channel is wanted */
+};
+
+struct snd_pcm_plugin_format {
+	snd_pcm_format_t format;
+	unsigned int rate;
+	unsigned int channels;
+};
+
+struct snd_pcm_plugin {
+	const char *name;		/* plug-in name */
+	int stream;
+	struct snd_pcm_plugin_format src_format;	/* source format */
+	struct snd_pcm_plugin_format dst_format;	/* destination format */
+	int src_width;			/* sample width in bits */
+	int dst_width;			/* sample width in bits */
+	snd_pcm_access_t access;
+	snd_pcm_sframes_t (*src_frames)(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t dst_frames);
+	snd_pcm_sframes_t (*dst_frames)(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t src_frames);
+	snd_pcm_sframes_t (*client_channels)(struct snd_pcm_plugin *plugin,
+					     snd_pcm_uframes_t frames,
+					     struct snd_pcm_plugin_channel **channels);
+	snd_pcm_sframes_t (*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);
+	int (*action)(struct snd_pcm_plugin *plugin,
+		      enum snd_pcm_plugin_action action,
+		      unsigned long data);
+	struct snd_pcm_plugin *prev;
+	struct snd_pcm_plugin *next;
+	struct snd_pcm_substream *plug;
+	void *private_data;
+	void (*private_free)(struct snd_pcm_plugin *plugin);
+	char *buf;
+	snd_pcm_uframes_t buf_frames;
+	struct snd_pcm_plugin_channel *buf_channels;
+	char extra_data[0];
+};
+
+int snd_pcm_plugin_build(struct snd_pcm_substream *handle,
+                         const char *name,
+                         struct snd_pcm_plugin_format *src_format,
+                         struct snd_pcm_plugin_format *dst_format,
+                         size_t extra,
+                         struct snd_pcm_plugin **ret);
+int snd_pcm_plugin_free(struct snd_pcm_plugin *plugin);
+int snd_pcm_plugin_clear(struct snd_pcm_plugin **first);
+int snd_pcm_plug_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t frames);
+snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t drv_size);
+snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t clt_size);
+
+#define FULL ROUTE_PLUGIN_RESOLUTION
+#define HALF ROUTE_PLUGIN_RESOLUTION / 2
+
+int snd_pcm_plugin_build_io(struct snd_pcm_substream *handle,
+			    struct snd_pcm_hw_params *params,
+			    struct snd_pcm_plugin **r_plugin);
+int snd_pcm_plugin_build_linear(struct snd_pcm_substream *handle,
+				struct snd_pcm_plugin_format *src_format,
+				struct snd_pcm_plugin_format *dst_format,
+				struct snd_pcm_plugin **r_plugin);
+int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *handle,
+			       struct snd_pcm_plugin_format *src_format,
+			       struct snd_pcm_plugin_format *dst_format,
+			       struct snd_pcm_plugin **r_plugin);
+int snd_pcm_plugin_build_rate(struct snd_pcm_substream *handle,
+			      struct snd_pcm_plugin_format *src_format,
+			      struct snd_pcm_plugin_format *dst_format,
+			      struct snd_pcm_plugin **r_plugin);
+int snd_pcm_plugin_build_route(struct snd_pcm_substream *handle,
+			       struct snd_pcm_plugin_format *src_format,
+			       struct snd_pcm_plugin_format *dst_format,
+		               struct snd_pcm_plugin **r_plugin);
+int snd_pcm_plugin_build_copy(struct snd_pcm_substream *handle,
+			      struct snd_pcm_plugin_format *src_format,
+			      struct snd_pcm_plugin_format *dst_format,
+			      struct snd_pcm_plugin **r_plugin);
+
+int snd_pcm_plug_format_plugins(struct snd_pcm_substream *substream,
+				struct snd_pcm_hw_params *params,
+				struct snd_pcm_hw_params *slave_params);
+
+snd_pcm_format_t snd_pcm_plug_slave_format(snd_pcm_format_t format,
+					   struct snd_mask *format_mask);
+
+int snd_pcm_plugin_append(struct snd_pcm_plugin *plugin);
+
+snd_pcm_sframes_t snd_pcm_plug_write_transfer(struct snd_pcm_substream *handle,
+					      struct snd_pcm_plugin_channel *src_channels,
+					      snd_pcm_uframes_t size);
+snd_pcm_sframes_t snd_pcm_plug_read_transfer(struct snd_pcm_substream *handle,
+					     struct snd_pcm_plugin_channel *dst_channels_final,
+					     snd_pcm_uframes_t size);
+
+snd_pcm_sframes_t snd_pcm_plug_client_channels_buf(struct snd_pcm_substream *handle,
+						   char *buf, snd_pcm_uframes_t count,
+						   struct snd_pcm_plugin_channel **channels);
+
+snd_pcm_sframes_t snd_pcm_plugin_client_channels(struct snd_pcm_plugin *plugin,
+						 snd_pcm_uframes_t frames,
+						 struct snd_pcm_plugin_channel **channels);
+
+int snd_pcm_area_silence(const struct snd_pcm_channel_area *dst_channel,
+			 size_t dst_offset,
+			 size_t samples, snd_pcm_format_t format);
+int snd_pcm_area_copy(const struct snd_pcm_channel_area *src_channel,
+		      size_t src_offset,
+		      const struct snd_pcm_channel_area *dst_channel,
+		      size_t dst_offset,
+		      size_t samples, snd_pcm_format_t format);
+
+void *snd_pcm_plug_buf_alloc(struct snd_pcm_substream *plug, snd_pcm_uframes_t size);
+void snd_pcm_plug_buf_unlock(struct snd_pcm_substream *plug, void *ptr);
+snd_pcm_sframes_t snd_pcm_oss_write3(struct snd_pcm_substream *substream,
+				     const char *ptr, snd_pcm_uframes_t size,
+				     int in_kernel);
+snd_pcm_sframes_t snd_pcm_oss_read3(struct snd_pcm_substream *substream,
+				    char *ptr, snd_pcm_uframes_t size, int in_kernel);
+snd_pcm_sframes_t snd_pcm_oss_writev3(struct snd_pcm_substream *substream,
+				      void **bufs, snd_pcm_uframes_t frames,
+				      int in_kernel);
+snd_pcm_sframes_t snd_pcm_oss_readv3(struct snd_pcm_substream *substream,
+				     void **bufs, snd_pcm_uframes_t frames,
+				     int in_kernel);
+
+#else
+
+static inline snd_pcm_sframes_t snd_pcm_plug_client_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t drv_size) { return drv_size; }
+static inline snd_pcm_sframes_t snd_pcm_plug_slave_size(struct snd_pcm_substream *handle, snd_pcm_uframes_t clt_size) { return clt_size; }
+static inline int snd_pcm_plug_slave_format(int format, struct snd_mask *format_mask) { return format; }
+
+#endif
+
+#ifdef PLUGIN_DEBUG
+#define pdprintf(fmt, args...) printk(KERN_DEBUG "plugin: " fmt, ##args)
+#else
+#define pdprintf(fmt, args...)
+#endif
+
+#endif				/* __PCM_PLUGIN_H */

sound/core/oss/rate.c

@@ -0,0 +1,348 @@
+/*
+ *  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 <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) {
+				S2 = *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;
+
+	if (snd_BUG_ON(!plugin))
+		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;
+
+	if (snd_BUG_ON(!plugin))
+		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;
+
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+#ifdef CONFIG_SND_DEBUG
+	{
+		unsigned int channel;
+		for (channel = 0; channel < plugin->src_format.channels; channel++) {
+			if (snd_BUG_ON(src_channels[channel].area.first % 8 ||
+				       src_channels[channel].area.step % 8))
+				return -ENXIO;
+			if (snd_BUG_ON(dst_channels[channel].area.first % 8 ||
+				       dst_channels[channel].area.step % 8))
+				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)
+{
+	if (snd_BUG_ON(!plugin))
+		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;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+
+	if (snd_BUG_ON(src_format->channels != dst_format->channels))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->channels <= 0))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->format != SNDRV_PCM_FORMAT_S16))
+		return -ENXIO;
+	if (snd_BUG_ON(dst_format->format != SNDRV_PCM_FORMAT_S16))
+		return -ENXIO;
+	if (snd_BUG_ON(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;
+}

sound/core/oss/route.c

@@ -0,0 +1,109 @@
+/*
+ *  Route Plug-In
+ *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
+ *
+ *
+ *   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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include "pcm_plugin.h"
+
+static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts,
+		       snd_pcm_uframes_t frames, snd_pcm_format_t format)
+{
+	int dst = 0;
+	for (; dst < ndsts; ++dst) {
+		if (dvp->wanted)
+			snd_pcm_area_silence(&dvp->area, 0, frames, format);
+		dvp->enabled = 0;
+		dvp++;
+	}
+}
+
+static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel,
+			     struct snd_pcm_plugin_channel *dst_channel,
+			     snd_pcm_uframes_t frames, snd_pcm_format_t format)
+{
+	dst_channel->enabled = 1;
+	snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format);
+}
+
+static snd_pcm_sframes_t route_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)
+{
+	int nsrcs, ndsts, dst;
+	struct snd_pcm_plugin_channel *dvp;
+	snd_pcm_format_t format;
+
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+
+	nsrcs = plugin->src_format.channels;
+	ndsts = plugin->dst_format.channels;
+
+	format = plugin->dst_format.format;
+	dvp = dst_channels;
+	if (nsrcs <= 1) {
+		/* expand to all channels */
+		for (dst = 0; dst < ndsts; ++dst) {
+			copy_area(src_channels, dvp, frames, format);
+			dvp++;
+		}
+		return frames;
+	}
+
+	for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) {
+		copy_area(src_channels, dvp, frames, format);
+		dvp++;
+		src_channels++;
+	}
+	if (dst < ndsts)
+		zero_areas(dvp, ndsts - dst, frames, format);
+	return frames;
+}
+
+int snd_pcm_plugin_build_route(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)
+{
+	struct snd_pcm_plugin *plugin;
+	int err;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+	if (snd_BUG_ON(src_format->rate != dst_format->rate))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->format != dst_format->format))
+		return -ENXIO;
+
+	err = snd_pcm_plugin_build(plug, "route conversion",
+				   src_format, dst_format, 0, &plugin);
+	if (err < 0)
+		return err;
+
+	plugin->transfer = route_transfer;
+	*r_plugin = plugin;
+	return 0;
+}