path: root/sound/core/control.c

/*
 *  Routines for driver control interface
 *  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
 *
 */

#include <linux/threads.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <sound/control.h>

/* max number of user-defined controls */
#define MAX_USER_CONTROLS	32

struct snd_kctl_ioctl {
	struct list_head list;		/* list of all ioctls */
	snd_kctl_ioctl_func_t fioctl;
};

static DECLARE_RWSEM(snd_ioctl_rwsem);
static LIST_HEAD(snd_control_ioctls);
#ifdef CONFIG_COMPAT
static LIST_HEAD(snd_control_compat_ioctls);
#endif

static int snd_ctl_open(struct inode *inode, struct file *file)
{
	unsigned long flags;
	struct snd_card *card;
	struct snd_ctl_file *ctl;
	int err;

	card = snd_lookup_minor_data(iminor(inode), SNDRV_DEVICE_TYPE_CONTROL);
	if (!card) {
		err = -ENODEV;
		goto __error1;
	}
	err = snd_card_file_add(card, file);
	if (err < 0) {
		err = -ENODEV;
		goto __error1;
	}
	if (!try_module_get(card->module)) {
		err = -EFAULT;
		goto __error2;
	}
	ctl = kzalloc(sizeof(*ctl), GFP_KERNEL);
	if (ctl == NULL) {
		err = -ENOMEM;
		goto __error;
	}
	INIT_LIST_HEAD(&ctl->events);
	init_waitqueue_head(&ctl->change_sleep);
	spin_lock_init(&ctl->read_lock);
	ctl->card = card;
	ctl->prefer_pcm_subdevice = -1;
	ctl->prefer_rawmidi_subdevice = -1;
	ctl->pid = current->pid;
	file->private_data = ctl;
	write_lock_irqsave(&card->ctl_files_rwlock, flags);
	list_add_tail(&ctl->list, &card->ctl_files);
	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
	return 0;

      __error:
	module_put(card->module);
      __error2:
	snd_card_file_remove(card, file);
      __error1:
      	return err;
}

static void snd_ctl_empty_read_queue(struct snd_ctl_file * ctl)
{
	unsigned long flags;
	struct snd_kctl_event *cread;
	
	spin_lock_irqsave(&ctl->read_lock, flags);
	while (!list_empty(&ctl->events)) {
		cread = snd_kctl_event(ctl->events.next);
		list_del(&cread->list);
		kfree(cread);
	}
	spin_unlock_irqrestore(&ctl->read_lock, flags);
}

static int snd_ctl_release(struct inode *inode, struct file *file)
{
	unsigned long flags;
	struct snd_card *card;
	struct snd_ctl_file *ctl;
	struct snd_kcontrol *control;
	unsigned int idx;

	ctl = file->private_data;
	file->private_data = NULL;
	card = ctl->card;
	write_lock_irqsave(&card->ctl_files_rwlock, flags);
	list_del(&ctl->list);
	write_unlock_irqrestore(&card->ctl_files_rwlock, flags);
	down_write(&card->controls_rwsem);
	list_for_each_entry(control, &card->controls, list)
		for (idx = 0; idx < control->count; idx++)
			if (control->vd[idx].owner == ctl)
				control->vd[idx].owner = NULL;
	up_write(&card->controls_rwsem);
	snd_ctl_empty_read_queue(ctl);
	kfree(ctl);
	module_put(card->module);
	snd_card_file_remove(card, file);
	return 0;
}

void snd_ctl_notify(struct snd_card *card, unsigned int mask,
		    struct snd_ctl_elem_id *id)
{
	unsigned long flags;
	struct snd_ctl_file *ctl;
	struct snd_kctl_event *ev;
	
	if (snd_BUG_ON(!card || !id))
		return;
	read_lock(&card->ctl_files_rwlock);
#if defined(CONFIG_SND_MIXER_OSS) || defined(CONFIG_SND_MIXER_OSS_MODULE)
	card->mixer_oss_change_count++;
#endif
	list_for_each_entry(ctl, &card->ctl_files, list) {
		if (!ctl->subscribed)
			continue;
		spin_lock_irqsave(&ctl->read_lock, flags);
		list_for_each_entry(ev, &ctl->events, list) {
			if (ev->id.numid == id->numid) {
				ev->mask |= mask;
				goto _found;
			}
		}
		ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
		if (ev) {
			ev->id = *id;
			ev->mask = mask;
			list_add_tail(&ev->list, &ctl->events);
		} else {
			snd_printk(KERN_ERR "No memory available to allocate event\n");
		}
	_found:
		wake_up(&ctl->change_sleep);
		spin_unlock_irqrestore(&ctl->read_lock, flags);
		kill_fasync(&ctl->fasync, SIGIO, POLL_IN);
	}
	read_unlock(&card->ctl_files_rwlock);
}

EXPORT_SYMBOL(snd_ctl_notify);

/**
 * snd_ctl_new - create a control instance from the template
 * @control: the control template
 * @access: the default control access
 *
 * Allocates a new struct snd_kcontrol instance and copies the given template 
 * to the new instance. It does not copy volatile data (access).
 *
 * Returns the pointer of the new instance, or NULL on failure.
 */
static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control,
					unsigned int access)
{
	struct snd_kcontrol *kctl;
	unsigned int idx;
	
	if (snd_BUG_ON(!control || !control->count))
		return NULL;
	kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL);
	if (kctl == NULL) {
		snd_printk(KERN_ERR "Cannot allocate control instance\n");
		return NULL;
	}
	*kctl = *control;
	for (idx = 0; idx < kctl->count; idx++)
		kctl->vd[idx].access = access;
	return kctl;
}

/**
 * snd_ctl_new1 - create a control instance from the template
 * @ncontrol: the initialization record
 * @private_data: the private data to set
 *
 * Allocates a new struct snd_kcontrol instance and initialize from the given 
 * template.  When the access field of ncontrol is 0, it's assumed as
 * READWRITE access. When the count field is 0, it's assumes as one.
 *
 * Returns the pointer of the newly generated instance, or NULL on failure.
 */
struct snd_kcontrol *snd_ctl_new1(const struct snd_kcontrol_new *ncontrol,
				  void *private_data)
{
	struct snd_kcontrol kctl;
	unsigned int access;
	
	if (snd_BUG_ON(!ncontrol || !ncontrol->info))
		return NULL;
	memset(&kctl, 0, sizeof(kctl));
	kctl.id.iface = ncontrol->iface;
	kctl.id.device = ncontrol->device;
	kctl.id.subdevice = ncontrol->subdevice;
	if (ncontrol->name) {
		strlcpy(kctl.id.name, ncontrol->name, sizeof(kctl.id.name));
		if (strcmp(ncontrol->name, kctl.id.name) != 0)
			snd_printk(KERN_WARNING
				   "Control name '%s' truncated to '%s'\n",
				   ncontrol->name, kctl.id.name);
	}
	kctl.id.index = ncontrol->index;
	kctl.count = ncontrol->count ? ncontrol->count : 1;
	access = ncontrol->access == 0 ? SNDRV_CTL_ELEM_ACCESS_READWRITE :
		 (ncontrol->access & (SNDRV_CTL_ELEM_ACCESS_READWRITE|
				      SNDRV_CTL_ELEM_ACCESS_INACTIVE|
		 		      SNDRV_CTL_ELEM_ACCESS_TLV_READWRITE|
		 		      SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK));
	kctl.info = ncontrol->info;
	kctl.get = ncontrol->get;
	kctl.put = ncontrol->put;
	kctl.tlv.p = ncontrol->tlv.p;
	kctl.private_value = ncontrol->private_value;
	kctl.private_data = private_data;
	return snd_ctl_new(&kctl, access);
}

EXPORT_SYMBOL(snd_ctl_new1);

/**
 * snd_ctl_free_one - release the control instance
 * @kcontrol: the control instance
 *
 * Releases the control instance created via snd_ctl_new()
 * or snd_ctl_new1().
 * Don't call this after the control was added to the card.
 */
void snd_ctl_free_one(struct snd_kcontrol *kcontrol)
{
	if (kcontrol) {
		if (kcontrol->private_free)
			kcontrol->private_free(kcontrol);
		kfree(kcontrol);
	}
}

EXPORT_SYMBOL(snd_ctl_free_one);

static unsigned int snd_ctl_hole_check(struct snd_card *card,
				       unsi