// SPDX-License-Identifier: GPL-2.0-only
/*
 * dice_hwdep.c - a part of driver for DICE based devices
 *
 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
 * Copyright (c) 2014 Takashi Sakamoto <o-takashi@sakamocchi.jp>
 */

#include "dice.h"

static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf,
                            long count, loff_t *offset)
{
        struct snd_dice *dice = hwdep->private_data;
        DEFINE_WAIT(wait);
        union snd_firewire_event event;

        spin_lock_irq(&dice->lock);

        while (!dice->dev_lock_changed && dice->notification_bits == 0) {
                prepare_to_wait(&dice->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
                spin_unlock_irq(&dice->lock);
                schedule();
                finish_wait(&dice->hwdep_wait, &wait);
                if (signal_pending(current))
                        return -ERESTARTSYS;
                spin_lock_irq(&dice->lock);
        }

        memset(&event, 0, sizeof(event));
        if (dice->dev_lock_changed) {
                event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
                event.lock_status.status = dice->dev_lock_count > 0;
                dice->dev_lock_changed = false;

                count = min_t(long, count, sizeof(event.lock_status));
        } else {
                event.dice_notification.type =
                                        SNDRV_FIREWIRE_EVENT_DICE_NOTIFICATION;
                event.dice_notification.notification = dice->notification_bits;
                dice->notification_bits = 0;

                count = min_t(long, count, sizeof(event.dice_notification));
        }

        spin_unlock_irq(&dice->lock);

        if (copy_to_user(buf, &event, count))
                return -EFAULT;

        return count;
}

static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
                               poll_table *wait)
{
        struct snd_dice *dice = hwdep->private_data;

        poll_wait(file, &dice->hwdep_wait, wait);

        guard(spinlock_irq)(&dice->lock);
        if (dice->dev_lock_changed || dice->notification_bits != 0)
                return EPOLLIN | EPOLLRDNORM;
        else
                return 0;
}

static int hwdep_get_info(struct snd_dice *dice, void __user *arg)
{
        struct fw_device *dev = fw_parent_device(dice->unit);
        struct snd_firewire_get_info info;

        memset(&info, 0, sizeof(info));
        info.type = SNDRV_FIREWIRE_TYPE_DICE;
        info.card = dev->card->index;
        *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
        *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
        strscpy(info.device_name, dev_name(&dev->device),
                sizeof(info.device_name));

        if (copy_to_user(arg, &info, sizeof(info)))
                return -EFAULT;

        return 0;
}

static int hwdep_lock(struct snd_dice *dice)
{
        guard(spinlock_irq)(&dice->lock);

        if (dice->dev_lock_count == 0) {
                dice->dev_lock_count = -1;
                return 0;
        } else {
                return -EBUSY;
        }
}

static int hwdep_unlock(struct snd_dice *dice)
{
        guard(spinlock_irq)(&dice->lock);

        if (dice->dev_lock_count == -1) {
                dice->dev_lock_count = 0;
                return 0;
        } else {
                return -EBADFD;
        }
}

static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
{
        struct snd_dice *dice = hwdep->private_data;

        guard(spinlock_irq)(&dice->lock);
        if (dice->dev_lock_count == -1)
                dice->dev_lock_count = 0;

        return 0;
}

static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
                       unsigned int cmd, unsigned long arg)
{
        struct snd_dice *dice = hwdep->private_data;

        switch (cmd) {
        case SNDRV_FIREWIRE_IOCTL_GET_INFO:
                return hwdep_get_info(dice, (void __user *)arg);
        case SNDRV_FIREWIRE_IOCTL_LOCK:
                return hwdep_lock(dice);
        case SNDRV_FIREWIRE_IOCTL_UNLOCK:
                return hwdep_unlock(dice);
        default:
                return -ENOIOCTLCMD;
        }
}

#ifdef CONFIG_COMPAT
static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
                              unsigned int cmd, unsigned long arg)
{
        return hwdep_ioctl(hwdep, file, cmd,
                           (unsigned long)compat_ptr(arg));
}
#else
#define hwdep_compat_ioctl NULL
#endif

int snd_dice_create_hwdep(struct snd_dice *dice)
{
        static const struct snd_hwdep_ops ops = {
                .read         = hwdep_read,
                .release      = hwdep_release,
                .poll         = hwdep_poll,
                .ioctl        = hwdep_ioctl,
                .ioctl_compat = hwdep_compat_ioctl,
        };
        struct snd_hwdep *hwdep;
        int err;

        err = snd_hwdep_new(dice->card, "DICE", 0, &hwdep);
        if (err < 0)
                return err;
        strscpy(hwdep->name, "DICE");
        hwdep->iface = SNDRV_HWDEP_IFACE_FW_DICE;
        hwdep->ops = ops;
        hwdep->private_data = dice;
        hwdep->exclusive = true;

        return 0;
}