control.c

linux 内核源代码

			return -EINVAL;
		break;
	case SNDRV_CTL_ELEM_TYPE_BYTES:
		private_size = sizeof(unsigned char);
		if (info->count > 512)
			return -EINVAL;
		break;
	case SNDRV_CTL_ELEM_TYPE_IEC958:
		private_size = sizeof(struct snd_aes_iec958);
		if (info->count != 1)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}
	private_size *= info->count;
	ue = kzalloc(sizeof(struct user_element) + private_size, GFP_KERNEL);
	if (ue == NULL)
		return -ENOMEM;
	ue->info = *info;
	ue->info.access = 0;
	ue->elem_data = (char *)ue + sizeof(*ue);
	ue->elem_data_size = private_size;
	kctl.private_free = snd_ctl_elem_user_free;
	_kctl = snd_ctl_new(&kctl, access);
	if (_kctl == NULL) {
		kfree(ue);
		return -ENOMEM;
	}
	_kctl->private_data = ue;
	for (idx = 0; idx < _kctl->count; idx++)
		_kctl->vd[idx].owner = file;
	err = snd_ctl_add(card, _kctl);
	if (err < 0)
		return err;

	down_write(&card->controls_rwsem);
	card->user_ctl_count++;
	up_write(&card->controls_rwsem);

	return 0;
}

static int snd_ctl_elem_add_user(struct snd_ctl_file *file,
				 struct snd_ctl_elem_info __user *_info, int replace)
{
	struct snd_ctl_elem_info info;
	if (copy_from_user(&info, _info, sizeof(info)))
		return -EFAULT;
	return snd_ctl_elem_add(file, &info, replace);
}

static int snd_ctl_elem_remove(struct snd_ctl_file *file,
			       struct snd_ctl_elem_id __user *_id)
{
	struct snd_ctl_elem_id id;
	int err;

	if (copy_from_user(&id, _id, sizeof(id)))
		return -EFAULT;
	err = snd_ctl_remove_unlocked_id(file, &id);
	if (! err) {
		struct snd_card *card = file->card;
		down_write(&card->controls_rwsem);
		card->user_ctl_count--;
		up_write(&card->controls_rwsem);
	}
	return err;
}

static int snd_ctl_subscribe_events(struct snd_ctl_file *file, int __user *ptr)
{
	int subscribe;
	if (get_user(subscribe, ptr))
		return -EFAULT;
	if (subscribe < 0) {
		subscribe = file->subscribed;
		if (put_user(subscribe, ptr))
			return -EFAULT;
		return 0;
	}
	if (subscribe) {
		file->subscribed = 1;
		return 0;
	} else if (file->subscribed) {
		snd_ctl_empty_read_queue(file);
		file->subscribed = 0;
	}
	return 0;
}

static int snd_ctl_tlv_ioctl(struct snd_ctl_file *file,
                             struct snd_ctl_tlv __user *_tlv,
                             int op_flag)
{
	struct snd_card *card = file->card;
	struct snd_ctl_tlv tlv;
	struct snd_kcontrol *kctl;
	struct snd_kcontrol_volatile *vd;
	unsigned int len;
	int err = 0;

	if (copy_from_user(&tlv, _tlv, sizeof(tlv)))
		return -EFAULT;
	if (tlv.length < sizeof(unsigned int) * 3)
		return -EINVAL;
	down_read(&card->controls_rwsem);
	kctl = snd_ctl_find_numid(card, tlv.numid);
	if (kctl == NULL) {
		err = -ENOENT;
		goto __kctl_end;
	}
	if (kctl->tlv.p == NULL) {
		err = -ENXIO;
		goto __kctl_end;
	}
	vd = &kctl->vd[tlv.numid - kctl->id.numid];
	if ((op_flag == 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_READ) == 0) ||
	    (op_flag > 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_WRITE) == 0) ||
	    (op_flag < 0 && (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_COMMAND) == 0)) {
	    	err = -ENXIO;
	    	goto __kctl_end;
	}
	if (vd->access & SNDRV_CTL_ELEM_ACCESS_TLV_CALLBACK) {
		if (file && vd->owner != NULL && vd->owner != file) {
			err = -EPERM;
			goto __kctl_end;
		}
		err = kctl->tlv.c(kctl, op_flag, tlv.length, _tlv->tlv); 
		if (err > 0) {
			up_read(&card->controls_rwsem);
			snd_ctl_notify(card, SNDRV_CTL_EVENT_MASK_TLV, &kctl->id);
			return 0;
		}
	} else {
		if (op_flag) {
			err = -ENXIO;
			goto __kctl_end;
		}
		len = kctl->tlv.p[1] + 2 * sizeof(unsigned int);
		if (tlv.length < len) {
			err = -ENOMEM;
			goto __kctl_end;
		}
		if (copy_to_user(_tlv->tlv, kctl->tlv.p, len))
			err = -EFAULT;
	}
      __kctl_end:
	up_read(&card->controls_rwsem);
	return err;
}

static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	struct snd_ctl_file *ctl;
	struct snd_card *card;
	struct snd_kctl_ioctl *p;
	void __user *argp = (void __user *)arg;
	int __user *ip = argp;
	int err;

	ctl = file->private_data;
	card = ctl->card;
	snd_assert(card != NULL, return -ENXIO);
	switch (cmd) {
	case SNDRV_CTL_IOCTL_PVERSION:
		return put_user(SNDRV_CTL_VERSION, ip) ? -EFAULT : 0;
	case SNDRV_CTL_IOCTL_CARD_INFO:
		return snd_ctl_card_info(card, ctl, cmd, argp);
	case SNDRV_CTL_IOCTL_ELEM_LIST:
		return snd_ctl_elem_list(card, argp);
	case SNDRV_CTL_IOCTL_ELEM_INFO:
		return snd_ctl_elem_info_user(ctl, argp);
	case SNDRV_CTL_IOCTL_ELEM_READ:
		return snd_ctl_elem_read_user(card, argp);
	case SNDRV_CTL_IOCTL_ELEM_WRITE:
		return snd_ctl_elem_write_user(ctl, argp);
	case SNDRV_CTL_IOCTL_ELEM_LOCK:
		return snd_ctl_elem_lock(ctl, argp);
	case SNDRV_CTL_IOCTL_ELEM_UNLOCK:
		return snd_ctl_elem_unlock(ctl, argp);
	case SNDRV_CTL_IOCTL_ELEM_ADD:
		return snd_ctl_elem_add_user(ctl, argp, 0);
	case SNDRV_CTL_IOCTL_ELEM_REPLACE:
		return snd_ctl_elem_add_user(ctl, argp, 1);
	case SNDRV_CTL_IOCTL_ELEM_REMOVE:
		return snd_ctl_elem_remove(ctl, argp);
	case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
		return snd_ctl_subscribe_events(ctl, ip);
	case SNDRV_CTL_IOCTL_TLV_READ:
		return snd_ctl_tlv_ioctl(ctl, argp, 0);
	case SNDRV_CTL_IOCTL_TLV_WRITE:
		return snd_ctl_tlv_ioctl(ctl, argp, 1);
	case SNDRV_CTL_IOCTL_TLV_COMMAND:
		return snd_ctl_tlv_ioctl(ctl, argp, -1);
	case SNDRV_CTL_IOCTL_POWER:
		return -ENOPROTOOPT;
	case SNDRV_CTL_IOCTL_POWER_STATE:
#ifdef CONFIG_PM
		return put_user(card->power_state, ip) ? -EFAULT : 0;
#else
		return put_user(SNDRV_CTL_POWER_D0, ip) ? -EFAULT : 0;
#endif
	}
	down_read(&snd_ioctl_rwsem);
	list_for_each_entry(p, &snd_control_ioctls, list) {
		err = p->fioctl(card, ctl, cmd, arg);
		if (err != -ENOIOCTLCMD) {
			up_read(&snd_ioctl_rwsem);
			return err;
		}
	}
	up_read(&snd_ioctl_rwsem);
	snd_printdd("unknown ioctl = 0x%x\n", cmd);
	return -ENOTTY;
}

static ssize_t snd_ctl_read(struct file *file, char __user *buffer,
			    size_t count, loff_t * offset)
{
	struct snd_ctl_file *ctl;
	int err = 0;
	ssize_t result = 0;

	ctl = file->private_data;
	snd_assert(ctl != NULL && ctl->card != NULL, return -ENXIO);
	if (!ctl->subscribed)
		return -EBADFD;
	if (count < sizeof(struct snd_ctl_event))
		return -EINVAL;
	spin_lock_irq(&ctl->read_lock);
	while (count >= sizeof(struct snd_ctl_event)) {
		struct snd_ctl_event ev;
		struct snd_kctl_event *kev;
		while (list_empty(&ctl->events)) {
			wait_queue_t wait;
			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
				err = -EAGAIN;
				goto __end_lock;
			}
			init_waitqueue_entry(&wait, current);
			add_wait_queue(&ctl->change_sleep, &wait);
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(&ctl->read_lock);
			schedule();
			remove_wait_queue(&ctl->change_sleep, &wait);
			if (signal_pending(current))
				return -ERESTARTSYS;
			spin_lock_irq(&ctl->read_lock);
		}
		kev = snd_kctl_event(ctl->events.next);
		ev.type = SNDRV_CTL_EVENT_ELEM;
		ev.data.elem.mask = kev->mask;
		ev.data.elem.id = kev->id;
		list_del(&kev->list);
		spin_unlock_irq(&ctl->read_lock);
		kfree(kev);
		if (copy_to_user(buffer, &ev, sizeof(struct snd_ctl_event))) {
			err = -EFAULT;
			goto __end;
		}
		spin_lock_irq(&ctl->read_lock);
		buffer += sizeof(struct snd_ctl_event);
		count -= sizeof(struct snd_ctl_event);
		result += sizeof(struct snd_ctl_event);
	}
      __end_lock:
	spin_unlock_irq(&ctl->read_lock);
      __end:
      	return result > 0 ? result : err;
}

static unsigned int snd_ctl_poll(struct file *file, poll_table * wait)
{
	unsigned int mask;
	struct snd_ctl_file *ctl;

	ctl = file->private_data;
	if (!ctl->subscribed)
		return 0;
	poll_wait(file, &ctl->change_sleep, wait);

	mask = 0;
	if (!list_empty(&ctl->events))
		mask |= POLLIN | POLLRDNORM;

	return mask;
}

/*
 * register the device-specific control-ioctls.
 * called from each device manager like pcm.c, hwdep.c, etc.
 */
static int _snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn, struct list_head *lists)
{
	struct snd_kctl_ioctl *pn;

	pn = kzalloc(sizeof(struct snd_kctl_ioctl), GFP_KERNEL);
	if (pn == NULL)
		return -ENOMEM;
	pn->fioctl = fcn;
	down_write(&snd_ioctl_rwsem);
	list_add_tail(&pn->list, lists);
	up_write(&snd_ioctl_rwsem);
	return 0;
}

int snd_ctl_register_ioctl(snd_kctl_ioctl_func_t fcn)
{
	return _snd_ctl_register_ioctl(fcn, &snd_control_ioctls);
}

EXPORT_SYMBOL(snd_ctl_register_ioctl);

#ifdef CONFIG_COMPAT
int snd_ctl_register_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
	return _snd_ctl_register_ioctl(fcn, &snd_control_compat_ioctls);
}

EXPORT_SYMBOL(snd_ctl_register_ioctl_compat);
#endif

/*
 * de-register the device-specific control-ioctls.
 */
static int _snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn,
				     struct list_head *lists)
{
	struct snd_kctl_ioctl *p;

	snd_assert(fcn != NULL, return -EINVAL);
	down_write(&snd_ioctl_rwsem);
	list_for_each_entry(p, lists, list) {
		if (p->fioctl == fcn) {
			list_del(&p->list);
			up_write(&snd_ioctl_rwsem);
			kfree(p);
			return 0;
		}
	}
	up_write(&snd_ioctl_rwsem);
	snd_BUG();
	return -EINVAL;
}

int snd_ctl_unregister_ioctl(snd_kctl_ioctl_func_t fcn)
{
	return _snd_ctl_unregister_ioctl(fcn, &snd_control_ioctls);
}

EXPORT_SYMBOL(snd_ctl_unregister_ioctl);

#ifdef CONFIG_COMPAT
int snd_ctl_unregister_ioctl_compat(snd_kctl_ioctl_func_t fcn)
{
	return _snd_ctl_unregister_ioctl(fcn, &snd_control_compat_ioctls);
}

EXPORT_SYMBOL(snd_ctl_unregister_ioctl_compat);
#endif

static int snd_ctl_fasync(int fd, struct file * file, int on)
{
	struct snd_ctl_file *ctl;
	int err;
	ctl = file->private_data;
	err = fasync_helper(fd, file, on, &ctl->fasync);
	if (err < 0)
		return err;
	return 0;
}

/*
 * ioctl32 compat
 */
#ifdef CONFIG_COMPAT
#include "control_compat.c"
#else
#define snd_ctl_ioctl_compat	NULL
#endif

/*
 *  INIT PART
 */

static const struct file_operations snd_ctl_f_ops =
{
	.owner =	THIS_MODULE,
	.read =		snd_ctl_read,
	.open =		snd_ctl_open,
	.release =	snd_ctl_release,
	.poll =		snd_ctl_poll,
	.unlocked_ioctl =	snd_ctl_ioctl,
	.compat_ioctl =	snd_ctl_ioctl_compat,
	.fasync =	snd_ctl_fasync,
};

/*
 * registration of the control device
 */
static int snd_ctl_dev_register(struct snd_device *device)
{
	struct snd_card *card = device->device_data;
	int err, cardnum;
	char name[16];

	snd_assert(card != NULL, return -ENXIO);
	cardnum = card->number;
	snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);
	sprintf(name, "controlC%i", cardnum);
	if ((err = snd_register_device(SNDRV_DEVICE_TYPE_CONTROL, card, -1,
				       &snd_ctl_f_ops, card, name)) < 0)
		return err;
	return 0;
}

/*
 * disconnection of the control device
 */
static int snd_ctl_dev_disconnect(struct snd_device *device)
{
	struct snd_card *card = device->device_data;
	struct snd_ctl_file *ctl;
	int err, cardnum;

	snd_assert(card != NULL, return -ENXIO);
	cardnum = card->number;
	snd_assert(cardnum >= 0 && cardnum < SNDRV_CARDS, return -ENXIO);

	down_read(&card->controls_rwsem);
	list_for_each_entry(ctl, &card->ctl_files, list) {
		wake_up(&ctl->change_sleep);
		kill_fasync(&ctl->fasync, SIGIO, POLL_ERR);
	}
	up_read(&card->controls_rwsem);

	if ((err = snd_unregister_device(SNDRV_DEVICE_TYPE_CONTROL,
					 card, -1)) < 0)
		return err;
	return 0;
}

/*
 * free all controls
 */
static int snd_ctl_dev_free(struct snd_device *device)
{
	struct snd_card *card = device->device_data;
	struct snd_kcontrol *control;

	down_write(&card->controls_rwsem);
	while (!list_empty(&card->controls)) {
		control = snd_kcontrol(card->controls.next);
		snd_ctl_remove(card, control);
	}
	up_write(&card->controls_rwsem);
	return 0;
}

/*
 * create control core:
 * called from init.c
 */
int snd_ctl_create(struct snd_card *card)
{
	static struct snd_device_ops ops = {
		.dev_free = snd_ctl_dev_free,
		.dev_register =	snd_ctl_dev_register,
		.dev_disconnect = snd_ctl_dev_disconnect,
	};

	snd_assert(card != NULL, return -ENXIO);
	return snd_device_new(card, SNDRV_DEV_CONTROL, card, &ops);
}

/*
 * Frequently used control callbacks
 */
int snd_ctl_boolean_mono_info(struct snd_kcontrol *kcontrol,
			      struct snd_ctl_elem_info *uinfo)
{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
	uinfo->count = 1;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 1;
	return 0;
}

EXPORT_SYMBOL(snd_ctl_boolean_mono_info);

int snd_ctl_boolean_stereo_info(struct snd_kcontrol *kcontrol,
				struct snd_ctl_elem_info *uinfo)
{
	uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
	uinfo->count = 2;
	uinfo->value.integer.min = 0;
	uinfo->value.integer.max = 1;
	return 0;
}

EXPORT_SYMBOL(snd_ctl_boolean_stereo_info);