/* *  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 <sound/driver.h>#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){	struct linear_priv *data;	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);	data = (struct linear_priv *)plugin->extra_data;	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	convert(plugin, src_channels, dst_channels, frames);	return frames;}static void init_data(struct linear_priv *data, int src_format, int 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 = cpu_to_le32(0x80000000);		else			data->flip = 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;	snd_assert(r_plugin != NULL, return -ENXIO);	*r_plugin = NULL;	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);	snd_assert(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;}