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

#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/minors.h>
#include <sound/info.h>
#include <linux/sound.h>
#include <linux/mutex.h>

#define SNDRV_OSS_MINORS 256

static struct snd_minor *snd_oss_minors[SNDRV_OSS_MINORS];
static DEFINE_MUTEX(sound_oss_mutex);

/* NOTE: This function increments the refcount of the associated card like
 * snd_lookup_minor_data(); the caller must call snd_card_unref() appropriately
 */
void *snd_lookup_oss_minor_data(unsigned int minor, int type)
{
        struct snd_minor *mreg;
        void *private_data;

        if (minor >= ARRAY_SIZE(snd_oss_minors))
                return NULL;
        guard(mutex)(&sound_oss_mutex);
        mreg = snd_oss_minors[minor];
        if (mreg && mreg->type == type) {
                private_data = mreg->private_data;
                if (private_data && mreg->card_ptr)
                        get_device(&mreg->card_ptr->card_dev);
        } else
                private_data = NULL;
        return private_data;
}
EXPORT_SYMBOL(snd_lookup_oss_minor_data);

static int snd_oss_kernel_minor(int type, struct snd_card *card, int dev)
{
        int minor;

        switch (type) {
        case SNDRV_OSS_DEVICE_TYPE_MIXER:
                if (snd_BUG_ON(!card || dev < 0 || dev > 1))
                        return -EINVAL;
                minor = SNDRV_MINOR_OSS(card->number, (dev ? SNDRV_MINOR_OSS_MIXER1 : SNDRV_MINOR_OSS_MIXER));
                break;
        case SNDRV_OSS_DEVICE_TYPE_SEQUENCER:
                minor = SNDRV_MINOR_OSS_SEQUENCER;
                break;
        case SNDRV_OSS_DEVICE_TYPE_MUSIC:
                minor = SNDRV_MINOR_OSS_MUSIC;
                break;
        case SNDRV_OSS_DEVICE_TYPE_PCM:
                if (snd_BUG_ON(!card || dev < 0 || dev > 1))
                        return -EINVAL;
                minor = SNDRV_MINOR_OSS(card->number, (dev ? SNDRV_MINOR_OSS_PCM1 : SNDRV_MINOR_OSS_PCM));
                break;
        case SNDRV_OSS_DEVICE_TYPE_MIDI:
                if (snd_BUG_ON(!card || dev < 0 || dev > 1))
                        return -EINVAL;
                minor = SNDRV_MINOR_OSS(card->number, (dev ? SNDRV_MINOR_OSS_MIDI1 : SNDRV_MINOR_OSS_MIDI));
                break;
        case SNDRV_OSS_DEVICE_TYPE_DMFM:
                minor = SNDRV_MINOR_OSS(card->number, SNDRV_MINOR_OSS_DMFM);
                break;
        case SNDRV_OSS_DEVICE_TYPE_SNDSTAT:
                minor = SNDRV_MINOR_OSS_SNDSTAT;
                break;
        default:
                return -EINVAL;
        }
        if (minor < 0 || minor >= SNDRV_OSS_MINORS)
                return -EINVAL;
        return minor;
}

int snd_register_oss_device(int type, struct snd_card *card, int dev,
                            const struct file_operations *f_ops, void *private_data)
{
        int minor = snd_oss_kernel_minor(type, card, dev);
        int minor_unit;
        struct snd_minor *preg;
        int cidx = SNDRV_MINOR_OSS_CARD(minor);
        int track2 = -1;
        int register1 = -1, register2 = -1;
        struct device *carddev = snd_card_get_device_link(card);

        if (card && card->number >= SNDRV_MINOR_OSS_DEVICES)
                return 0; /* ignore silently */
        if (minor < 0)
                return minor;
        preg = kmalloc_obj(struct snd_minor);
        if (preg == NULL)
                return -ENOMEM;
        preg->type = type;
        preg->card = card ? card->number : -1;
        preg->device = dev;
        preg->f_ops = f_ops;
        preg->private_data = private_data;
        preg->card_ptr = card;
        guard(mutex)(&sound_oss_mutex);
        snd_oss_minors[minor] = preg;
        minor_unit = SNDRV_MINOR_OSS_DEVICE(minor);
        switch (minor_unit) {
        case SNDRV_MINOR_OSS_PCM:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_AUDIO);
                break;
        case SNDRV_MINOR_OSS_MIDI:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_DMMIDI);
                break;
        case SNDRV_MINOR_OSS_MIDI1:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_DMMIDI1);
                break;
        }
        register1 = register_sound_special_device(f_ops, minor, carddev);
        if (register1 != minor)
                goto __end;
        if (track2 >= 0) {
                register2 = register_sound_special_device(f_ops, track2,
                                                          carddev);
                if (register2 != track2)
                        goto __end;
                snd_oss_minors[track2] = preg;
        }
        return 0;

      __end:
        if (register2 >= 0)
                unregister_sound_special(register2);
        if (register1 >= 0)
                unregister_sound_special(register1);
        snd_oss_minors[minor] = NULL;
        kfree(preg);
        return -EBUSY;
}
EXPORT_SYMBOL(snd_register_oss_device);

int snd_unregister_oss_device(int type, struct snd_card *card, int dev)
{
        int minor = snd_oss_kernel_minor(type, card, dev);
        int cidx = SNDRV_MINOR_OSS_CARD(minor);
        int track2 = -1;
        struct snd_minor *mptr;

        if (card && card->number >= SNDRV_MINOR_OSS_DEVICES)
                return 0;
        if (minor < 0)
                return minor;
        guard(mutex)(&sound_oss_mutex);
        mptr = snd_oss_minors[minor];
        if (mptr == NULL)
                return -ENOENT;
        switch (SNDRV_MINOR_OSS_DEVICE(minor)) {
        case SNDRV_MINOR_OSS_PCM:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_AUDIO);
                break;
        case SNDRV_MINOR_OSS_MIDI:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_DMMIDI);
                break;
        case SNDRV_MINOR_OSS_MIDI1:
                track2 = SNDRV_MINOR_OSS(cidx, SNDRV_MINOR_OSS_DMMIDI1);
                break;
        }
        if (track2 >= 0)
                snd_oss_minors[track2] = NULL;
        snd_oss_minors[minor] = NULL;

        /* call unregister_sound_special() outside sound_oss_mutex;
         * otherwise may deadlock, as it can trigger the release of a card
         */
        unregister_sound_special(minor);
        if (track2 >= 0)
                unregister_sound_special(track2);

        kfree(mptr);
        return 0;
}
EXPORT_SYMBOL(snd_unregister_oss_device);

/*
 *  INFO PART
 */

#ifdef CONFIG_SND_PROC_FS
static const char *snd_oss_device_type_name(int type)
{
        switch (type) {
        case SNDRV_OSS_DEVICE_TYPE_MIXER:
                return "mixer";
        case SNDRV_OSS_DEVICE_TYPE_SEQUENCER:
        case SNDRV_OSS_DEVICE_TYPE_MUSIC:
                return "sequencer";
        case SNDRV_OSS_DEVICE_TYPE_PCM:
                return "digital audio";
        case SNDRV_OSS_DEVICE_TYPE_MIDI:
                return "raw midi";
        case SNDRV_OSS_DEVICE_TYPE_DMFM:
                return "hardware dependent";
        default:
                return "?";
        }
}

static void snd_minor_info_oss_read(struct snd_info_entry *entry,
                                    struct snd_info_buffer *buffer)
{
        int minor;
        struct snd_minor *mptr;

        guard(mutex)(&sound_oss_mutex);
        for (minor = 0; minor < SNDRV_OSS_MINORS; ++minor) {
                mptr = snd_oss_minors[minor];
                if (!mptr)
                        continue;
                if (mptr->card >= 0)
                        snd_iprintf(buffer, "%3i: [%i-%2i]: %s\n", minor,
                                    mptr->card, mptr->device,
                                    snd_oss_device_type_name(mptr->type));
                else
                        snd_iprintf(buffer, "%3i:       : %s\n", minor,
                                    snd_oss_device_type_name(mptr->type));
        }
}


int __init snd_minor_info_oss_init(void)
{
        struct snd_info_entry *entry;

        entry = snd_info_create_module_entry(THIS_MODULE, "devices", snd_oss_root);
        if (!entry)
                return -ENOMEM;
        entry->c.text.read = snd_minor_info_oss_read;
        return snd_info_register(entry); /* freed in error path */
}
#endif /* CONFIG_SND_PROC_FS */