path: root/sound/core/init.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Initialization routines
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/ctype.h>
#include <linux/pm.h>
#include <linux/debugfs.h>
#include <linux/completion.h>
#include <linux/interrupt.h>

#include <sound/core.h>
#include <sound/control.h>
#include <sound/info.h>

/* monitor files for graceful shutdown (hotplug) */
struct snd_monitor_file {
	struct file *file;
	const struct file_operations *disconnected_f_op;
	struct list_head shutdown_list;	/* still need to shutdown */
	struct list_head list;	/* link of monitor files */
};

static DEFINE_SPINLOCK(shutdown_lock);
static LIST_HEAD(shutdown_files);

static const struct file_operations snd_shutdown_f_ops;

/* locked for registering/using */
static DECLARE_BITMAP(snd_cards_lock, SNDRV_CARDS);
static struct snd_card *snd_cards[SNDRV_CARDS];

static DEFINE_MUTEX(snd_card_mutex);

static char *slots[SNDRV_CARDS];
module_param_array(slots, charp, NULL, 0444);
MODULE_PARM_DESC(slots, "Module names assigned to the slots.");

/* return non-zero if the given index is reserved for the given
 * module via slots option
 */
static int module_slot_match(struct module *module, int idx)
{
	int match = 1;
#ifdef MODULE
	const char *s1, *s2;

	if (!module || !*module->name || !slots[idx])
		return 0;

	s1 = module->name;
	s2 = slots[idx];
	if (*s2 == '!') {
		match = 0; /* negative match */
		s2++;
	}
	/* compare module name strings
	 * hyphens are handled as equivalent with underscore
	 */
	for (;;) {
		char c1 = *s1++;
		char c2 = *s2++;
		if (c1 == '-')
			c1 = '_';
		if (c2 == '-')
			c2 = '_';
		if (c1 != c2)
			return !match;
		if (!c1)
			break;
	}
#endif /* MODULE */
	return match;
}

#if IS_ENABLED(CONFIG_SND_MIXER_OSS)
int (*snd_mixer_oss_notify_callback)(struct snd_card *card, int free_flag);
EXPORT_SYMBOL(snd_mixer_oss_notify_callback);
#endif

static int check_empty_slot(struct module *module, int slot)
{
	return !slots[slot] || !*slots[slot];
}

/* return an empty slot number (>= 0) found in the given bitmask @mask.
 * @mask == -1 == 0xffffffff means: take any free slot up to 32
 * when no slot is available, return the original @mask as is.
 */
static int get_slot_from_bitmask(int mask, int (*check)(struct module *, int),
				 struct module *module)
{
	int slot;

	for (slot = 0; slot < SNDRV_CARDS; slot++) {
		if (slot < 32 && !(mask & (1U << slot)))
			continue;
		if (!test_bit(slot, snd_cards_lock)) {
			if (check(module, slot))
				return slot; /* found */
		}
	}
	return mask; /* unchanged */
}

/* the default release callback set in snd_device_initialize() below;
 * this is just NOP for now, as almost all jobs are already done in
 * dev_free callback of snd_device chain instead.
 */
static void default_release(struct device *dev)
{
}

/**
 * snd_device_initialize - Initialize struct device for sound devices
 * @dev: device to initialize
 * @card: card to assign, optional
 */
void snd_device_initialize(struct device *dev, struct snd_card *card)
{
	device_initialize(dev);
	if (card)
		dev->parent = &card->card_dev;
	dev->class = sound_class;
	dev->release = default_release;
}
EXPORT_SYMBOL_GPL(snd_device_initialize);

static int snd_card_do_free(struct snd_card *card);
static const struct attribute_group card_dev_attr_group;

static void release_card_device(struct device *dev)
{
	snd_card_do_free(dev_to_snd_card(dev));
}

/**
 *  snd_card_new - create and initialize a soundcard structure
 *  @parent: the parent device object
 *  @idx: card index (address) [0 ... (SNDRV_CARDS-1)]
 *  @xid: card identification (ASCII string)
 *  @module: top level module for locking
 *  @extra_size: allocate this extra size after the main soundcard structure
 *  @card_ret: the pointer to store the created card instance
 *
 *  The function allocates snd_card instance via kzalloc with the given
 *  space for the driver to use freely.  The allocated struct is stored
 *  in the given card_ret pointer.
 *
 *  Return: Zero if successful or a negative error code.
 */
int snd_card_new(struct device *parent, int idx, const char *xid,
		    struct module *module, int extra_size,
		    struct snd_card **card_ret)
{
	struct snd_card *card;
	int err;
#ifdef CONFIG_SND_DEBUG
	char name[8];
#endif

	if (snd_BUG_ON(!card_ret))
		return -EINVAL;
	*card_ret = NULL;

	if (extra_size < 0)
		extra_size = 0;
	card = kzalloc(sizeof(*card) + extra_size, GFP_KERNEL);
	if (!card)
		return -ENOMEM;
	if (extra_size > 0)
		card->private_data = (char *)card + sizeof(struct snd_card);
	if (xid)
		strscpy(card->id,