control.c

Linux Kernel 2.6.9 for OMAP1710

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

#include <sound/driver.h>
#include <linux/threads.h>
#include <linux/interrupt.h>
#include <linux/smp_lock.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>

typedef struct _snd_kctl_ioctl {
	struct list_head list;		/* list of all ioctls */
	snd_kctl_ioctl_func_t fioctl;
} snd_kctl_ioctl_t;

#define snd_kctl_ioctl(n) list_entry(n, snd_kctl_ioctl_t, list)

static DECLARE_RWSEM(snd_ioctl_rwsem);
static LIST_HEAD(snd_control_ioctls);

static int snd_ctl_open(struct inode *inode, struct file *file)
{
	int cardnum = SNDRV_MINOR_CARD(iminor(inode));
	unsigned long flags;
	snd_card_t *card;
	snd_ctl_file_t *ctl;
	int err;

	card = snd_cards[cardnum];
	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 = kcalloc(1, 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->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(snd_ctl_file_t * ctl)
{
	snd_kctl_event_t *cread;
	
	spin_lock(&ctl->read_lock);
	while (!list_empty(&ctl->events)) {
		cread = snd_kctl_event(ctl->events.next);
		list_del(&cread->list);
		kfree(cread);
	}
	spin_unlock(&ctl->read_lock);
}

static int snd_ctl_release(struct inode *inode, struct file *file)
{
	unsigned long flags;
	struct list_head *list;
	snd_card_t *card;
	snd_ctl_file_t *ctl;
	snd_kcontrol_t *control;
	unsigned int idx;

	ctl = file->private_data;
	fasync_helper(-1, file, 0, &ctl->fasync);
	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(list, &card->controls) {
		control = snd_kcontrol(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(snd_card_t *card, unsigned int mask, snd_ctl_elem_id_t *id)
{
	unsigned long flags;
	struct list_head *flist;
	snd_ctl_file_t *ctl;
	snd_kctl_event_t *ev;
	
	snd_runtime_check(card != NULL && id != NULL, 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(flist, &card->ctl_files) {
		struct list_head *elist;
		ctl = snd_ctl_file(flist);
		if (!ctl->subscribed)
			continue;
		spin_lock_irqsave(&ctl->read_lock, flags);
		list_for_each(elist, &ctl->events) {
			ev = snd_kctl_event(elist);
			if (ev->id.numid == id->numid) {
				ev->mask |= mask;
				goto _found;
			}
		}
		ev = kcalloc(1, 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);
}

/**
 * snd_ctl_new - create a control instance from the template
 * @control: the control template
 * @access: the default control access
 *
 * Allocates a new snd_kcontrol_t 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.
 */
snd_kcontrol_t *snd_ctl_new(snd_kcontrol_t * control, unsigned int access)
{
	snd_kcontrol_t *kctl;
	unsigned int idx;
	
	snd_runtime_check(control != NULL, return NULL);
	snd_runtime_check(control->count > 0, return NULL);
	kctl = kcalloc(1, sizeof(*kctl) + sizeof(snd_kcontrol_volatile_t) * control->count, GFP_KERNEL);
	if (kctl == NULL)
		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 snd_kcontrol_t 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.
 */
snd_kcontrol_t *snd_ctl_new1(snd_kcontrol_new_t * ncontrol, void *private_data)
{
	snd_kcontrol_t kctl;
	unsigned int access;
	
	snd_runtime_check(ncontrol != NULL, return NULL);
	snd_assert(ncontrol->info != NULL, 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));
	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_DINDIRECT|SNDRV_CTL_ELEM_ACCESS_INDIRECT));
	kctl.info = ncontrol->info;
	kctl.get = ncontrol->get;
	kctl.put = ncontrol->put;
	kctl.private_value = ncontrol->private_value;
	kctl.private_data = private_data;
	return snd_ctl_new(&kctl, access);
}

/**
 * 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(snd_kcontrol_t * kcontrol)
{
	if (kcontrol) {
		if (kcontrol->private_free)
			kcontrol->private_free(kcontrol);
		kfree(kcontrol);
	}
}

static unsigned int snd_ctl_hole_check(snd_card_t * card,
				       unsigned int count)
{
	struct list_head *list;
	snd_kcontrol_t *kctl;

	list_for_each(list, &card->controls) {
		kctl = snd_kcontrol(list);
		if ((kctl->id.numid <= card->last_numid &&
		     kctl->id.numid + kctl->count > card->last_numid) ||
		    (kctl->id.numid <= card->last_numid + count - 1 &&
		     kctl->id.numid + kctl->count > card->last_numid + count - 1))
		    	return card->last_numid = kctl->id.numid + kctl->count - 1;
	}
	return card->last_numid;
}

static int snd_ctl_find_hole(snd_card_t * card, unsigned int count)
{
	unsigned int last_numid, iter = 100000;

	last_numid = card->last_numid;
	while (last_numid != snd_ctl_hole_check(card, count)) {
		if (--iter == 0) {
			/* this situation is very unlikely */
			snd_printk(KERN_ERR "unable to allocate new control numid\n");
			return -ENOMEM;
		}
		last_numid = card->last_numid;
	}
	return 0;
}

/**
 * snd_ctl_add - add the control instance to the card
 * @card: the card instance
 * @kcontrol: the control instance to add
 *
 * Adds the control instance created via snd_ctl_new() or
 * snd_ctl_new1() to the given card. Assigns also an unique
 * numid used for fast search.
 *
 * Returns zero if successful, or a negative error code on failure.
 *
 * It frees automatically the control which cannot be added.
 */
int snd_ctl_add(snd_card_t * card, snd_kcontrol_t * kcontrol)
{
	snd_ctl_elem_id_t id;
	unsigned int idx;

	snd_runtime_check(card != NULL && kcontrol != NULL, return -EINVAL);
	snd_assert(kcontrol->info != NULL, return -EINVAL);
	id = kcontrol->id;
	down_write(&card->controls_rwsem);
	if (snd_ctl_find_id(card, &id)) {
		up_write(&card->controls_rwsem);
		snd_ctl_free_one(kcontrol);
		snd_printd(KERN_ERR "control %i:%i:%i:%s:%i is already present\n",
					id.iface,
					id.device,
					id.subdevice,
					id.name,
					id.index);
		return -EBUSY;
	}
	if (snd_ctl_find_hole(card, kcontrol->count) < 0) {
		up_write(&card->controls_rwsem);
		snd_ctl_free_one(kcontrol);
		return -ENOMEM;
	}
	list_add_tail(&kcontrol->list, &card->controls);
	card->controls_count += kcontrol->count;
	kcontrol->id.numid = card->last_numid + 1;
	card->last_numid += kcontrol->count;
	up_write(&card->controls_rwsem);
	for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_ADD, &id);
	return 0;
}

/**
 * snd_ctl_remove - remove the control from the card and release it
 * @card: the card instance
 * @kcontrol: the control instance to remove
 *
 * Removes the control from the card and then releases the instance.
 * You don't need to call snd_ctl_free_one(). You must be in
 * the write lock - down_write(&card->controls_rwsem).
 * 
 * Returns 0 if successful, or a negative error code on failure.
 */
int snd_ctl_remove(snd_card_t * card, snd_kcontrol_t * kcontrol)
{
	snd_ctl_elem_id_t id;
	unsigned int idx;

	snd_runtime_check(card != NULL && kcontrol != NULL, return -EINVAL);
	list_del(&kcontrol->list);
	card->controls_count -= kcontrol->count;
	id = kcontrol->id;
	for (idx = 0; idx < kcontrol->count; idx++, id.index++, id.numid++)
		snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_REMOVE, &id);
	snd_ctl_free_one(kcontrol);
	return 0;
}

/**
 * snd_ctl_remove_id - remove the control of the given id and release it
 * @card: the card instance
 * @id: the control id to remove
 *
 * Finds the control instance with the given id, removes it from the
 * card list and releases it.
 * 
 * Returns 0 if successful, or a negative error code on failure.
 */
int snd_ctl_remove_id(snd_card_t * card, snd_ctl_elem_id_t *id)
{
	snd_kcontrol_t *kctl;
	int ret;

	down_write(&card->controls_rwsem);
	kctl = snd_ctl_find_id(card, id);
	if (kctl == NULL) {
		up_write(&card->controls_rwsem);
		return -ENOENT;
	}
	ret = snd_ctl_remove(card, kctl);
	up_write(&card->controls_rwsem);
	return ret;
}

/**
 * snd_ctl_remove_unlocked_id - remove the unlocked control of the given id and release it
 * @file: active control handle
 * @id: the control id to remove
 *
 * Finds the control instance with the given id, removes it from the
 * card list and releases it.
 * 
 * Returns 0 if successful, or a negative error code on failure.
 */
static int snd_ctl_remove_unlocked_id(snd_ctl_file_t * file, snd_ctl_elem_id_t *id)
{
	snd_card_t *card = file->card;
	snd_kcontrol_t *kctl;
	int idx, ret;

	down_write(&card->controls_rwsem);
	kctl = snd_ctl_find_id(card, id);
	if (kctl == NULL) {
		up_write(&card->controls_rwsem);
		return -ENOENT;
	}
	for (idx = 0; idx < kctl->count; idx++)
		if (kctl->vd[idx].owner != NULL && kctl->vd[idx].owner != file) {
			up_write(&card->controls_rwsem);
			return -EBUSY;
		}
	ret = snd_ctl_remove(card, kctl);
	up_write(&card->controls_rwsem);
	return ret;
}

/**
 * snd_ctl_rename_id - replace the id of a control on the card
 * @card: the card instance
 * @src_id: the old id
 * @dst_id: the new id
 *
 * Finds the control with the old id from the card, and replaces the
 * id with the new one.
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_ctl_rename_id(snd_card_t * card, snd_ctl_elem_id_t *src_id, snd_ctl_elem_id_t *dst_id)
{
	snd_kcontrol_t *kctl;

	down_write(&card->controls_rwsem);
	kctl = snd_ctl_find_id(card, src_id);
	if (kctl == NULL) {
		up_write(&card->controls_rwsem);