path: root/sound/core/oss/pcm_plugin.c

/*
 *  PCM Plug-In shared (kernel/library) code
 *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.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 <sound/driver.h>
#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)

static int snd_pcm_plugin_src_channels_mask(struct snd_pcm_plugin *plugin,
					    unsigned long *dst_vmask,
					    unsigned long **src_vmask)
{
	unsigned long *vmask = plugin->src_vmask;
	bitmap_copy(vmask, dst_vmask, plugin->src_format.channels);
	*src_vmask = vmask;
	return 0;
}

static int snd_pcm_plugin_dst_channels_mask(struct snd_pcm_plugin *plugin,
					    unsigned long *src_vmask,
					    unsigned long **dst_vmask)
{
	unsigned long *vmask = plugin->dst_vmask;
	bitmap_copy(vmask, src_vmask, plugin->dst_format.channels);
	*dst_vmask = vmask;
	return 0;
}

/*
 *  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;
	snd_assert((size % 8) == 0, 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) {
		snd_assert((size % format->channels) == 0,);
		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;
	snd_assert(snd_pcm_plug_first(plug) != NULL, 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);
			snd_assert(frames > 0, return -ENXIO);
			plugin = plugin->next;
			err =