pcm_oss.c

是关于linux2.5.1的完全源码

/*
 *  Digital Audio (PCM) abstract layer / OSS compatible
 *  Copyright (c) by Jaroslav Kysela <[e-mail]>
 *
 *
 *   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
 *
 */

#if 0
#define PLUGIN_DEBUG
#endif

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include "pcm_plugin.h"
#include <sound/info.h>
#include <linux/soundcard.h>
#include <sound/initval.h>

static int snd_dsp_map[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = 0};
static int snd_adsp_map[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = 1};
static int snd_nonblock_open;

MODULE_AUTHOR("Jaroslav Kysela <[e-mail]>, Abramo Bagnara <[e-mail]>");
MODULE_DESCRIPTION("PCM OSS emulation for ALSA.");
MODULE_LICENSE("GPL");
MODULE_PARM(snd_dsp_map, "1-" __MODULE_STRING(SNDRV_CARDS) "i");
MODULE_PARM_DESC(snd_dsp_map, "PCM device number assigned to 1st OSS device.");
MODULE_PARM_SYNTAX(snd_dsp_map, "default:0,skill:advanced");
MODULE_PARM(snd_adsp_map, "1-" __MODULE_STRING(SNDRV_CARDS) "i");
MODULE_PARM_DESC(snd_adsp_map, "PCM device number assigned to 2nd OSS device.");
MODULE_PARM_SYNTAX(snd_adsp_map, "default:1,skill:advanced");
MODULE_PARM(snd_nonblock_open, "i");
MODULE_PARM_DESC(snd_nonblock_open, "Don't block opening busy PCM devices.");
MODULE_PARM_SYNTAX(snd_nonblock_open, "default:0,skill:advanced");

extern int snd_mixer_oss_ioctl_card(snd_card_t *card, unsigned int cmd, unsigned long arg);
static int snd_pcm_oss_get_rate(snd_pcm_oss_file_t *pcm_oss_file);
static int snd_pcm_oss_get_channels(snd_pcm_oss_file_t *pcm_oss_file);
static int snd_pcm_oss_get_format(snd_pcm_oss_file_t *pcm_oss_file);

EXPORT_NO_SYMBOLS;

static inline mm_segment_t snd_enter_user(void)
{
	mm_segment_t fs = get_fs();
	set_fs(get_ds());
	return fs;
}

static inline void snd_leave_user(mm_segment_t fs)
{
	set_fs(fs);
}

static inline void dec_mod_count(struct module *module)
{
	if (module)
		__MOD_DEC_USE_COUNT(module);
}

int snd_pcm_oss_plugin_clear(snd_pcm_substream_t *substream)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_pcm_plugin_t *plugin, *next;
	
	plugin = runtime->oss.plugin_first;
	while (plugin) {
		next = plugin->next;
		snd_pcm_plugin_free(plugin);
		plugin = next;
	}
	runtime->oss.plugin_first = runtime->oss.plugin_last = NULL;
	return 0;
}

int snd_pcm_plugin_insert(snd_pcm_plugin_t *plugin)
{
	snd_pcm_runtime_t *runtime = plugin->plug->runtime;
	plugin->next = runtime->oss.plugin_first;
	plugin->prev = NULL;
	if (runtime->oss.plugin_first) {
		runtime->oss.plugin_first->prev = plugin;
		runtime->oss.plugin_first = plugin;
	} else {
		runtime->oss.plugin_last =
		runtime->oss.plugin_first = plugin;
	}
	return 0;
}

int snd_pcm_plugin_append(snd_pcm_plugin_t *plugin)
{
	snd_pcm_runtime_t *runtime = plugin->plug->runtime;
	plugin->next = NULL;
	plugin->prev = runtime->oss.plugin_last;
	if (runtime->oss.plugin_last) {
		runtime->oss.plugin_last->next = plugin;
		runtime->oss.plugin_last = plugin;
	} else {
		runtime->oss.plugin_last =
		runtime->oss.plugin_first = plugin;
	}
	return 0;
}

static long snd_pcm_oss_bytes(snd_pcm_substream_t *substream, long frames)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	if (runtime->period_size == runtime->oss.period_bytes)
		return frames;
	if (runtime->period_size < runtime->oss.period_bytes)
		return frames * (runtime->oss.period_bytes / runtime->period_size);
	return frames / (runtime->period_size / runtime->oss.period_bytes);
}

static int snd_pcm_oss_format_from(int format)
{
	switch (format) {
	case AFMT_MU_LAW:	return SNDRV_PCM_FORMAT_MU_LAW;
	case AFMT_A_LAW:	return SNDRV_PCM_FORMAT_A_LAW;
	case AFMT_IMA_ADPCM:	return SNDRV_PCM_FORMAT_IMA_ADPCM;
	case AFMT_U8:		return SNDRV_PCM_FORMAT_U8;
	case AFMT_S16_LE:	return SNDRV_PCM_FORMAT_S16_LE;
	case AFMT_S16_BE:	return SNDRV_PCM_FORMAT_S16_BE;
	case AFMT_S8:		return SNDRV_PCM_FORMAT_S8;
	case AFMT_U16_LE:	return SNDRV_PCM_FORMAT_U16_LE;
	case AFMT_U16_BE:	return SNDRV_PCM_FORMAT_U16_BE;
	case AFMT_MPEG:		return SNDRV_PCM_FORMAT_MPEG;
	default:			return SNDRV_PCM_FORMAT_U8;
	}
}

static int snd_pcm_oss_format_to(int format)
{
	switch (format) {
	case SNDRV_PCM_FORMAT_MU_LAW:	return AFMT_MU_LAW;
	case SNDRV_PCM_FORMAT_A_LAW:	return AFMT_A_LAW;
	case SNDRV_PCM_FORMAT_IMA_ADPCM:	return AFMT_IMA_ADPCM;
	case SNDRV_PCM_FORMAT_U8:		return AFMT_U8;
	case SNDRV_PCM_FORMAT_S16_LE:	return AFMT_S16_LE;
	case SNDRV_PCM_FORMAT_S16_BE:	return AFMT_S16_BE;
	case SNDRV_PCM_FORMAT_S8:		return AFMT_S8;
	case SNDRV_PCM_FORMAT_U16_LE:	return AFMT_U16_LE;
	case SNDRV_PCM_FORMAT_U16_BE:	return AFMT_U16_BE;
	case SNDRV_PCM_FORMAT_MPEG:		return AFMT_MPEG;
	default:			return -EINVAL;
	}
}

static int snd_pcm_oss_period_size(snd_pcm_substream_t *substream, 
				   snd_pcm_hw_params_t *oss_params,
				   snd_pcm_hw_params_t *slave_params)
{
	size_t s;
	size_t oss_buffer_size, oss_period_size, oss_periods;
	size_t min_period_size, max_period_size;
	snd_pcm_runtime_t *runtime = substream->runtime;
	size_t oss_frame_size;

	oss_frame_size = snd_pcm_format_physical_width(params_format(oss_params)) *
			 params_channels(oss_params) / 8;

	oss_buffer_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, 0)) * oss_frame_size;
	oss_buffer_size = 1 << ld2(oss_buffer_size);
	if (atomic_read(&runtime->mmap_count)) {
		if (oss_buffer_size > runtime->oss.mmap_bytes)
			oss_buffer_size = runtime->oss.mmap_bytes;
	}

	if (substream->oss.setup &&
	    substream->oss.setup->period_size > 16)
		oss_period_size = substream->oss.setup->period_size;
	else if (runtime->oss.fragshift) {
		oss_period_size = 1 << runtime->oss.fragshift;
		if (oss_period_size > oss_buffer_size / 2)
			oss_period_size = oss_buffer_size / 2;
	} else {
		int sd;
		size_t bytes_per_sec = params_rate(oss_params) * snd_pcm_format_physical_width(params_format(oss_params)) * params_channels(oss_params) / 8;

		oss_period_size = oss_buffer_size;
		do {
			oss_period_size /= 2;
		} while (oss_period_size > bytes_per_sec);
		if (runtime->oss.subdivision == 0) {
			sd = 4;
			if (oss_period_size / sd > 4096)
				sd *= 2;
			if (oss_period_size / sd < 4096)
				sd = 1;
		} else
			sd = runtime->oss.subdivision;
		oss_period_size /= sd;
		if (oss_period_size < 16)
			oss_period_size = 16;
	}

	min_period_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_min(slave_params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 0));
	min_period_size *= oss_frame_size;
	min_period_size = 1 << (ld2(min_period_size - 1) + 1);
	if (oss_period_size < min_period_size)
		oss_period_size = min_period_size;

	max_period_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, 0));
	max_period_size *= oss_frame_size;
	max_period_size = 1 << ld2(max_period_size);
	if (oss_period_size > max_period_size)
		oss_period_size = max_period_size;

	oss_periods = oss_buffer_size / oss_period_size;

	if (substream->oss.setup) {
		if (substream->oss.setup->periods > 1)
			oss_periods = substream->oss.setup->periods;
	}

	s = snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_PERIODS, 0);
	if (runtime->oss.maxfrags && s > runtime->oss.maxfrags)
		s = runtime->oss.maxfrags;
	if (oss_periods > s)
		oss_periods = s;

	s = snd_pcm_hw_param_value_min(slave_params, SNDRV_PCM_HW_PARAM_PERIODS, 0);
	if (s < 2)
		s = 2;
	if (oss_periods < s)
		oss_periods = s;

	while (oss_period_size * oss_periods > oss_buffer_size)
		oss_period_size /= 2;

	snd_assert(oss_period_size >= 16, return -EINVAL);
	runtime->oss.period_bytes = oss_period_size;
	runtime->oss.periods = oss_periods;
	return 0;
}

static int snd_pcm_oss_change_params(snd_pcm_substream_t *substream)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_pcm_hw_params_t params, sparams;
	snd_pcm_sw_params_t sw_params;
	ssize_t oss_buffer_size, oss_period_size;
	size_t oss_frame_size;
	int err;
	int direct;
	int format, sformat, n;
	unsigned int sformat_mask;
	unsigned int mask;

	if (atomic_read(&runtime->mmap_count)) {
		direct = 1;
	} else {
		snd_pcm_oss_setup_t *setup = substream->oss.setup;
		direct = (setup != NULL && setup->direct);
	}

	_snd_pcm_hw_params_any(&sparams);
	_snd_pcm_hw_param_setinteger(&sparams, SNDRV_PCM_HW_PARAM_PERIODS);
	_snd_pcm_hw_param_min(&sparams, SNDRV_PCM_HW_PARAM_PERIODS, 2, 0);
	if (atomic_read(&runtime->mmap_count))
		mask = 1 << SNDRV_PCM_ACCESS_MMAP_INTERLEAVED;
	else {
		mask = 1 << SNDRV_PCM_ACCESS_RW_INTERLEAVED;
		if (!direct)
			mask |= 1 << SNDRV_PCM_ACCESS_RW_NONINTERLEAVED;
	}
	err = snd_pcm_hw_param_mask(substream, &sparams, SNDRV_PCM_HW_PARAM_ACCESS, &mask);
	if (err < 0) {
		snd_printd("No usable accesses\n");
		return -EINVAL;
	}
	snd_pcm_hw_param_near(substream, &sparams, SNDRV_PCM_HW_PARAM_RATE, runtime->oss.rate, 0);
	snd_pcm_hw_param_near(substream, &sparams, SNDRV_PCM_HW_PARAM_CHANNELS, runtime->oss.channels, 0);

	format = snd_pcm_oss_format_from(runtime->oss.format);

	sformat_mask = *hw_param_mask(&sparams, SNDRV_PCM_HW_PARAM_FORMAT);
	if (direct)
		sformat = format;
	else
		sformat = snd_pcm_plug_slave_format(format, sformat_mask);

	if (sformat < 0 || !(sformat_mask & (1 << sformat))) {
		for (sformat = 0; sformat <= SNDRV_PCM_FORMAT_LAST; sformat++) {
			if ((sformat_mask & (1 << sformat)) &&
			    snd_pcm_oss_format_to(sformat) >= 0)
				break;
		}
		if (sformat > SNDRV_PCM_FORMAT_LAST) {
			snd_printd("Cannot find a format!!!\n");
			return -EINVAL;
		}
	}
	err = _snd_pcm_hw_param_set(&sparams, SNDRV_PCM_HW_PARAM_FORMAT, sformat, 0);
	snd_assert(err >= 0, return err);

	if (direct) {
		params = sparams;
	} else {
		_snd_pcm_hw_params_any(&params);
		_snd_pcm_hw_param_set(&params, SNDRV_PCM_HW_PARAM_ACCESS,
				      SNDRV_PCM_ACCESS_RW_INTERLEAVED, 0);
		_snd_pcm_hw_param_set(&params, SNDRV_PCM_HW_PARAM_FORMAT,
				      snd_pcm_oss_format_from(runtime->oss.format), 0);
		_snd_pcm_hw_param_set(&params, SNDRV_PCM_HW_PARAM_CHANNELS,
				      runtime->oss.channels, 0);
		_snd_pcm_hw_param_set(&params, SNDRV_PCM_HW_PARAM_RATE,
				      runtime->oss.rate, 0);
		pdprintf("client: access = %i, format = %i, channels = %i, rate = %i\n",
			 params_access(&params), params_format(&params),
			 params_channels(&params), params_rate(&params));
	}
	pdprintf("slave: access = %i, format = %i, channels = %i, rate = %i\n",
		 params_access(&sparams), params_format(&sparams),
		 params_channels(&sparams), params_rate(&sparams));

	oss_frame_size = snd_pcm_format_physical_width(params_format(&params)) *
			 params_channels(&params) / 8;

	snd_pcm_oss_plugin_clear(substream);
	if (!direct) {
		/* add necessary plugins */
		snd_pcm_oss_plugin_clear(substream);
		if ((err = snd_pcm_plug_format_plugins(substream,
						       &params, 
						       &sparams)) < 0) {
			snd_printd("snd_pcm_plug_format_plugins failed: %i\n", err);
			snd_pcm_oss_plugin_clear(substream);
			return err;
		}
		if (runtime->oss.plugin_first) {
			snd_pcm_plugin_t *plugin;
			if ((err = snd_pcm_plugin_build_io(substream, &sparams, &plugin)) < 0) {
				snd_printd("snd_pcm_plugin_build_io failed: %i\n", err);
				snd_pcm_oss_plugin_clear(substream);
				return err;
			}
			if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
				err = snd_pcm_plugin_append(plugin);
			} else {
				err = snd_pcm_plugin_insert(plugin);
			}
			if (err < 0) {
				snd_pcm_oss_plugin_clear(substream);
				return err;
			}
		}
	}

	err = snd_pcm_oss_period_size(substream, &params, &sparams);
	if (err < 0)
		return err;

	n = snd_pcm_plug_slave_size(substream, runtime->oss.period_bytes / oss_frame_size);
	err = snd_pcm_hw_param_near(substream, &sparams, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, n, 0);
	snd_assert(err >= 0, return err);

	err = snd_pcm_hw_param_near(substream, &sparams, SNDRV_PCM_HW_PARAM_PERIODS,
				     runtime->oss.periods, 0);
	snd_assert(err >= 0, return err);

	snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DROP, 0);

	if ((err = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_HW_PARAMS, &sparams)) < 0) {
		snd_printd("HW_PARAMS failed: %i\n", err);
		return err;
	}

	memset(&sw_params, 0, sizeof(sw_params));
	if (runtime->oss.trigger) {
		sw_params.start_threshold = 1;
	} else {
		sw_params.start_threshold = runtime->boundary;
	}
	if (atomic_read(&runtime->mmap_count))
		sw_params.stop_threshold = runtime->boundary;
	else
		sw_params.stop_threshold = runtime->buffer_size;
	sw_params.tstamp_mode = SNDRV_PCM_TSTAMP_NONE;
	sw_params.period_step = 1;
	sw_params.sleep_min = 0;
	sw_params.avail_min = runtime->period_size;
	sw_params.xfer_align = 1;
	sw_params.silence_threshold = 0;
	sw_params.silence_size = 0;

	if ((err = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_SW_PARAMS, &sw_params)) < 0) {
		snd_printd("SW_PARAMS failed: %i\n", err);
		return err;
	}
	runtime->control->avail_min = runtime->period_size;

	runtime->oss.periods = params_periods(&sparams);
	oss_period_size = snd_pcm_plug_client_size(substream, params_period_size(&sparams));
	snd_assert(oss_period_size >= 0, return -EINVAL);
	if (runtime->oss.plugin_first) {
		err = snd_pcm_plug_alloc(substream, oss_period_size);
		if (err < 0)
			return err;
	}
	oss_period_size *= oss_frame_size;

	oss_buffer_size = oss_period_size * runtime->oss.periods;
	snd_assert(oss_buffer_size >= 0, return -EINVAL);

	runtime->oss.period_bytes = oss_period_size;
	runtime->oss.buffer_bytes = oss_buffer_size;

	pdprintf("oss: period bytes = %i, buffer bytes = %i\n",
		 runtime->oss.period_bytes,
		 runtime->oss.buffer_bytes);
	pdprintf("slave: period_size = %i, buffer_size = %i\n",
		 params_period_size(&sparams),
		 params_buffer_size(&sparams));