pcm_oss.c

linux 内核源代码

/*
 *  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
#if 0
#define OSS_DEBUG
#endif

#include <sound/driver.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/vmalloc.h>
#include <linux/moduleparam.h>
#include <linux/string.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>

#define OSS_ALSAEMULVER		_SIOR ('M', 249, int)

static int dsp_map[SNDRV_CARDS];
static int adsp_map[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = 1};
static int nonblock_open = 1;

MODULE_AUTHOR("Jaroslav Kysela <[e-mail]>, Abramo Bagnara <[e-mail]>");
MODULE_DESCRIPTION("PCM OSS emulation for ALSA.");
MODULE_LICENSE("GPL");
module_param_array(dsp_map, int, NULL, 0444);
MODULE_PARM_DESC(dsp_map, "PCM device number assigned to 1st OSS device.");
module_param_array(adsp_map, int, NULL, 0444);
MODULE_PARM_DESC(adsp_map, "PCM device number assigned to 2nd OSS device.");
module_param(nonblock_open, bool, 0644);
MODULE_PARM_DESC(nonblock_open, "Don't block opening busy PCM devices.");
MODULE_ALIAS_SNDRV_MINOR(SNDRV_MINOR_OSS_PCM);
MODULE_ALIAS_SNDRV_MINOR(SNDRV_MINOR_OSS_PCM1);

extern int snd_mixer_oss_ioctl_card(struct snd_card *card, unsigned int cmd, unsigned long arg);
static int snd_pcm_oss_get_rate(struct snd_pcm_oss_file *pcm_oss_file);
static int snd_pcm_oss_get_channels(struct snd_pcm_oss_file *pcm_oss_file);
static int snd_pcm_oss_get_format(struct snd_pcm_oss_file *pcm_oss_file);

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);
}

/*
 * helper functions to process hw_params
 */
static int snd_interval_refine_min(struct snd_interval *i, unsigned int min, int openmin)
{
	int changed = 0;
	if (i->min < min) {
		i->min = min;
		i->openmin = openmin;
		changed = 1;
	} else if (i->min == min && !i->openmin && openmin) {
		i->openmin = 1;
		changed = 1;
	}
	if (i->integer) {
		if (i->openmin) {
			i->min++;
			i->openmin = 0;
		}
	}
	if (snd_interval_checkempty(i)) {
		snd_interval_none(i);
		return -EINVAL;
	}
	return changed;
}

static int snd_interval_refine_max(struct snd_interval *i, unsigned int max, int openmax)
{
	int changed = 0;
	if (i->max > max) {
		i->max = max;
		i->openmax = openmax;
		changed = 1;
	} else if (i->max == max && !i->openmax && openmax) {
		i->openmax = 1;
		changed = 1;
	}
	if (i->integer) {
		if (i->openmax) {
			i->max--;
			i->openmax = 0;
		}
	}
	if (snd_interval_checkempty(i)) {
		snd_interval_none(i);
		return -EINVAL;
	}
	return changed;
}

static int snd_interval_refine_set(struct snd_interval *i, unsigned int val)
{
	struct snd_interval t;
	t.empty = 0;
	t.min = t.max = val;
	t.openmin = t.openmax = 0;
	t.integer = 1;
	return snd_interval_refine(i, &t);
}

/**
 * snd_pcm_hw_param_value_min
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Return the minimum value for field PAR.
 */
static unsigned int
snd_pcm_hw_param_value_min(const struct snd_pcm_hw_params *params,
			   snd_pcm_hw_param_t var, int *dir)
{
	if (hw_is_mask(var)) {
		if (dir)
			*dir = 0;
		return snd_mask_min(hw_param_mask_c(params, var));
	}
	if (hw_is_interval(var)) {
		const struct snd_interval *i = hw_param_interval_c(params, var);
		if (dir)
			*dir = i->openmin;
		return snd_interval_min(i);
	}
	return -EINVAL;
}

/**
 * snd_pcm_hw_param_value_max
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Return the maximum value for field PAR.
 */
static unsigned int
snd_pcm_hw_param_value_max(const struct snd_pcm_hw_params *params,
			   snd_pcm_hw_param_t var, int *dir)
{
	if (hw_is_mask(var)) {
		if (dir)
			*dir = 0;
		return snd_mask_max(hw_param_mask_c(params, var));
	}
	if (hw_is_interval(var)) {
		const struct snd_interval *i = hw_param_interval_c(params, var);
		if (dir)
			*dir = - (int) i->openmax;
		return snd_interval_max(i);
	}
	return -EINVAL;
}

static int _snd_pcm_hw_param_mask(struct snd_pcm_hw_params *params,
				  snd_pcm_hw_param_t var,
				  const struct snd_mask *val)
{
	int changed;
	changed = snd_mask_refine(hw_param_mask(params, var), val);
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}

static int snd_pcm_hw_param_mask(struct snd_pcm_substream *pcm,
				 struct snd_pcm_hw_params *params,
				 snd_pcm_hw_param_t var,
				 const struct snd_mask *val)
{
	int changed = _snd_pcm_hw_param_mask(params, var, val);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		if (err < 0)
			return err;
	}
	return 0;
}

static int _snd_pcm_hw_param_min(struct snd_pcm_hw_params *params,
				 snd_pcm_hw_param_t var, unsigned int val,
				 int dir)
{
	int changed;
	int open = 0;
	if (dir) {
		if (dir > 0) {
			open = 1;
		} else if (dir < 0) {
			if (val > 0) {
				open = 1;
				val--;
			}
		}
	}
	if (hw_is_mask(var))
		changed = snd_mask_refine_min(hw_param_mask(params, var),
					      val + !!open);
	else if (hw_is_interval(var))
		changed = snd_interval_refine_min(hw_param_interval(params, var),
						  val, open);
	else
		return -EINVAL;
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}

/**
 * snd_pcm_hw_param_min
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @val: minimal value
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS remove from PAR all 
 * values < VAL. Reduce configuration space accordingly.
 * Return new minimum or -EINVAL if the configuration space is empty
 */
static int snd_pcm_hw_param_min(struct snd_pcm_substream *pcm,
				struct snd_pcm_hw_params *params,
				snd_pcm_hw_param_t var, unsigned int val,
				int *dir)
{
	int changed = _snd_pcm_hw_param_min(params, var, val, dir ? *dir : 0);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		if (err < 0)
			return err;
	}
	return snd_pcm_hw_param_value_min(params, var, dir);
}

static int _snd_pcm_hw_param_max(struct snd_pcm_hw_params *params,
				 snd_pcm_hw_param_t var, unsigned int val,
				 int dir)
{
	int changed;
	int open = 0;
	if (dir) {
		if (dir < 0) {
			open = 1;
		} else if (dir > 0) {
			open = 1;
			val++;
		}
	}
	if (hw_is_mask(var)) {
		if (val == 0 && open) {
			snd_mask_none(hw_param_mask(params, var));
			changed = -EINVAL;
		} else
			changed = snd_mask_refine_max(hw_param_mask(params, var),
						      val - !!open);
	} else if (hw_is_interval(var))
		changed = snd_interval_refine_max(hw_param_interval(params, var),
						  val, open);
	else
		return -EINVAL;
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}

/**
 * snd_pcm_hw_param_max
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @val: maximal value
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS remove from PAR all 
 *  values >= VAL + 1. Reduce configuration space accordingly.
 *  Return new maximum or -EINVAL if the configuration space is empty
 */
static int snd_pcm_hw_param_max(struct snd_pcm_substream *pcm,
				struct snd_pcm_hw_params *params,
				snd_pcm_hw_param_t var, unsigned int val,
				int *dir)
{
	int changed = _snd_pcm_hw_param_max(params, var, val, dir ? *dir : 0);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		if (err < 0)
			return err;
	}
	return snd_pcm_hw_param_value_max(params, var, dir);
}

static int boundary_sub(int a, int adir,
			int b, int bdir,
			int *c, int *cdir)
{
	adir = adir < 0 ? -1 : (adir > 0 ? 1 : 0);
	bdir = bdir < 0 ? -1 : (bdir > 0 ? 1 : 0);
	*c = a - b;
	*cdir = adir - bdir;
	if (*cdir == -2) {
		(*c)--;
	} else if (*cdir == 2) {
		(*c)++;
	}
	return 0;
}

static int boundary_lt(unsigned int a, int adir,
		       unsigned int b, int bdir)
{
	if (adir < 0) {
		a--;
		adir = 1;
	} else if (adir > 0)
		adir = 1;
	if (bdir < 0) {
		b--;
		bdir = 1;
	} else if (bdir > 0)
		bdir = 1;
	return a < b || (a == b && adir < bdir);
}

/* Return 1 if min is nearer to best than max */
static int boundary_nearer(int min, int mindir,
			   int best, int bestdir,
			   int max, int maxdir)
{
	int dmin, dmindir;
	int dmax, dmaxdir;
	boundary_sub(best, bestdir, min, mindir, &dmin, &dmindir);
	boundary_sub(max, maxdir, best, bestdir, &dmax, &dmaxdir);
	return boundary_lt(dmin, dmindir, dmax, dmaxdir);
}

/**
 * snd_pcm_hw_param_near
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @best: value to set
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS set PAR to the available value
 * nearest to VAL. Reduce configuration space accordingly.
 * This function cannot be called for SNDRV_PCM_HW_PARAM_ACCESS,
 * SNDRV_PCM_HW_PARAM_FORMAT, SNDRV_PCM_HW_PARAM_SUBFORMAT.
 * Return the value found.
  */
static int snd_pcm_hw_param_near(struct snd_pcm_substream *pcm,
				 struct snd_pcm_hw_params *params,
				 snd_pcm_hw_param_t var, unsigned int best,
				 int *dir)
{
	struct snd_pcm_hw_params *save = NULL;
	int v;
	unsigned int saved_min;
	int last = 0;
	int min, max;
	int mindir, maxdir;
	int valdir = dir ? *dir : 0;
	/* FIXME */
	if (best > INT_MAX)
		best = INT_MAX;
	min = max = best;
	mindir = maxdir = valdir;
	if (maxdir > 0)
		maxdir = 0;
	else if (maxdir == 0)
		maxdir = -1;
	else {
		maxdir = 1;
		max--;
	}
	save = kmalloc(sizeof(*save), GFP_KERNEL);
	if (save == NULL)
		return -ENOMEM;
	*save = *params;
	saved_min = min;
	min = snd_pcm_hw_param_min(pcm, params, var, min, &mindir);
	if (min >= 0) {
		struct snd_pcm_hw_params *params1;
		if (max < 0)
			goto _end;
		if ((unsigned int)min == saved_min && mindir == valdir)
			goto _end;
		params1 = kmalloc(sizeof(*params1), GFP_KERNEL);
		if (params1 == NULL) {
			kfree(save);
			return -ENOMEM;
		}
		*params1 = *save;
		max = snd_pcm_hw_param_max(pcm, params1, var, max, &maxdir);
		if (max < 0) {
			kfree(params1);
			goto _end;
		}
		if (boundary_nearer(max, maxdir, best, valdir, min, mindir)) {
			*params = *params1;
			last = 1;
		}
		kfree(params1);
	} else {
		*params = *save;
		max = snd_pcm_hw_param_max(pcm, params, var, max, &maxdir);
		snd_assert(max >= 0, return -EINVAL);
		last = 1;
	}
 _end:
 	kfree(save);
	if (last)
		v = snd_pcm_hw_param_last(pcm, params, var, dir);