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

#include <linux/slab.h>
#include <linux/time.h>
#include <linux/export.h>
#include <linux/errno.h>
#include <sound/core.h>

/**
 * snd_device_new - create an ALSA device component
 * @card: the card instance
 * @type: the device type, SNDRV_DEV_XXX
 * @device_data: the data pointer of this device
 * @ops: the operator table
 *
 * Creates a new device component for the given data pointer.
 * The device will be assigned to the card and managed together
 * by the card.
 *
 * The data pointer plays a role as the identifier, too, so the
 * pointer address must be unique and unchanged.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_device_new(struct snd_card *card, enum snd_device_type type,
                   void *device_data, const struct snd_device_ops *ops)
{
        struct snd_device *dev;
        struct list_head *p;

        if (snd_BUG_ON(!card || !device_data || !ops))
                return -ENXIO;
        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;
        INIT_LIST_HEAD(&dev->list);
        dev->card = card;
        dev->type = type;
        dev->state = SNDRV_DEV_BUILD;
        dev->device_data = device_data;
        dev->ops = ops;

        /* insert the entry in an incrementally sorted list */
        list_for_each_prev(p, &card->devices) {
                struct snd_device *pdev = list_entry(p, struct snd_device, list);
                if ((unsigned int)pdev->type <= (unsigned int)type)
                        break;
        }

        list_add(&dev->list, p);
        return 0;
}
EXPORT_SYMBOL(snd_device_new);

static void __snd_device_disconnect(struct snd_device *dev)
{
        if (dev->state == SNDRV_DEV_REGISTERED) {
                if (dev->ops->dev_disconnect &&
                    dev->ops->dev_disconnect(dev))
                        dev_err(dev->card->dev, "device disconnect failure\n");
                dev->state = SNDRV_DEV_DISCONNECTED;
        }
}

static void __snd_device_free(struct snd_device *dev)
{
        /* unlink */
        list_del(&dev->list);

        __snd_device_disconnect(dev);
        if (dev->ops->dev_free) {
                if (dev->ops->dev_free(dev))
                        dev_err(dev->card->dev, "device free failure\n");
        }
        kfree(dev);
}

static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
{
        struct snd_device *dev;

        list_for_each_entry(dev, &card->devices, list)
                if (dev->device_data == device_data)
                        return dev;

        return NULL;
}

/**
 * snd_device_disconnect - disconnect the device
 * @card: the card instance
 * @device_data: the data pointer to disconnect
 *
 * Turns the device into the disconnection state, invoking
 * dev_disconnect callback, if the device was already registered.
 *
 * Usually called from snd_card_disconnect().
 *
 * Return: Zero if successful, or a negative error code on failure or if the
 * device not found.
 */
void snd_device_disconnect(struct snd_card *card, void *device_data)
{
        struct snd_device *dev;

        if (snd_BUG_ON(!card || !device_data))
                return;
        dev = look_for_dev(card, device_data);
        if (dev)
                __snd_device_disconnect(dev);
        else
                dev_dbg(card->dev, "device disconnect %p (from %pS), not found\n",
                        device_data, __builtin_return_address(0));
}
EXPORT_SYMBOL_GPL(snd_device_disconnect);

/**
 * snd_device_free - release the device from the card
 * @card: the card instance
 * @device_data: the data pointer to release
 *
 * Removes the device from the list on the card and invokes the
 * callbacks, dev_disconnect and dev_free, corresponding to the state.
 * Then release the device.
 */
void snd_device_free(struct snd_card *card, void *device_data)
{
        struct snd_device *dev;
        
        if (snd_BUG_ON(!card || !device_data))
                return;
        dev = look_for_dev(card, device_data);
        if (dev)
                __snd_device_free(dev);
        else
                dev_dbg(card->dev, "device free %p (from %pS), not found\n",
                        device_data, __builtin_return_address(0));
}
EXPORT_SYMBOL(snd_device_free);

static int __snd_device_register(struct snd_device *dev)
{
        if (dev->state == SNDRV_DEV_BUILD) {
                if (dev->ops->dev_register) {
                        int err = dev->ops->dev_register(dev);
                        if (err < 0)
                                return err;
                }
                dev->state = SNDRV_DEV_REGISTERED;
        }
        return 0;
}

/**
 * snd_device_register - register the device
 * @card: the card instance
 * @device_data: the data pointer to register
 *
 * Registers the device which was already created via
 * snd_device_new().  Usually this is called from snd_card_register(),
 * but it can be called later if any new devices are created after
 * invocation of snd_card_register().
 *
 * Return: Zero if successful, or a negative error code on failure or if the
 * device not found.
 */
int snd_device_register(struct snd_card *card, void *device_data)
{
        struct snd_device *dev;

        if (snd_BUG_ON(!card || !device_data))
                return -ENXIO;
        dev = look_for_dev(card, device_data);
        if (dev)
                return __snd_device_register(dev);
        snd_BUG();
        return -ENXIO;
}
EXPORT_SYMBOL(snd_device_register);

/*
 * register all the devices on the card.
 * called from init.c
 */
int snd_device_register_all(struct snd_card *card)
{
        struct snd_device *dev;
        int err;
        
        if (snd_BUG_ON(!card))
                return -ENXIO;
        list_for_each_entry(dev, &card->devices, list) {
                err = __snd_device_register(dev);
                if (err < 0)
                        return err;
        }
        return 0;
}

/*
 * disconnect all the devices on the card.
 * called from init.c
 */
void snd_device_disconnect_all(struct snd_card *card)
{
        struct snd_device *dev;

        if (snd_BUG_ON(!card))
                return;
        list_for_each_entry_reverse(dev, &card->devices, list)
                __snd_device_disconnect(dev);
}

/*
 * release all the devices on the card.
 * called from init.c
 */
void snd_device_free_all(struct snd_card *card)
{
        struct snd_device *dev, *next;

        if (snd_BUG_ON(!card))
                return;
        list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
                /* exception: free ctl and lowlevel stuff later */
                if (dev->type == SNDRV_DEV_CONTROL ||
                    dev->type == SNDRV_DEV_LOWLEVEL)
                        continue;
                __snd_device_free(dev);
        }

        /* free all */
        list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
                __snd_device_free(dev);
}

/**
 * snd_device_get_state - Get the current state of the given device
 * @card: the card instance
 * @device_data: the data pointer to release
 *
 * Returns the current state of the given device object.  For the valid
 * device, either @SNDRV_DEV_BUILD, @SNDRV_DEV_REGISTERED or
 * @SNDRV_DEV_DISCONNECTED is returned.
 * Or for a non-existing device, -1 is returned as an error.
 */
int snd_device_get_state(struct snd_card *card, void *device_data)
{
        struct snd_device *dev;

        dev = look_for_dev(card, device_data);
        if (dev)
                return dev->state;
        return -1;
}
EXPORT_SYMBOL_GPL(snd_device_get_state);