Quelle  digi00x-hwdep.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * digi00x-hwdep.c - a part of driver for Digidesign Digi 002/003 family
 *
 * Copyright (c) 2014-2015 Takashi Sakamoto
 */

/*
 * This codes give three functionality.
 *
 * 1.get firewire node information
 * 2.get notification about starting/stopping stream
 * 3.lock/unlock stream
 * 4.get asynchronous messaging
 */

#include "digi00x.h"

static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
         loff_t *offset)
{
 struct snd_dg00x *dg00x = hwdep->private_data;
 DEFINE_WAIT(wait);
 union snd_firewire_event event;

 spin_lock_irq(&dg00x->lock);

 while (!dg00x->dev_lock_changed && dg00x->msg == 0) {
  prepare_to_wait(&dg00x->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
  spin_unlock_irq(&dg00x->lock);
  schedule();
  finish_wait(&dg00x->hwdep_wait, &wait);
  if (signal_pending(current))
   return -ERESTARTSYS;
  spin_lock_irq(&dg00x->lock);
 }

 memset(&event, 0, sizeof(event));
 if (dg00x->dev_lock_changed) {
  event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
  event.lock_status.status = (dg00x->dev_lock_count > 0);
  dg00x->dev_lock_changed = false;

  count = min_t(long, count, sizeof(event.lock_status));
 } else {
  event.digi00x_message.type =
     SNDRV_FIREWIRE_EVENT_DIGI00X_MESSAGE;
  event.digi00x_message.message = dg00x->msg;
  dg00x->msg = 0;

  count = min_t(long, count, sizeof(event.digi00x_message));
 }

 spin_unlock_irq(&dg00x->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_dg00x *dg00x = hwdep->private_data;
 __poll_t events;

 poll_wait(file, &dg00x->hwdep_wait, wait);

 spin_lock_irq(&dg00x->lock);
 if (dg00x->dev_lock_changed || dg00x->msg)
  events = EPOLLIN | EPOLLRDNORM;
 else
  events = 0;
 spin_unlock_irq(&dg00x->lock);

 return events;
}

static int hwdep_get_info(struct snd_dg00x *dg00x, void __user *arg)
{
 struct fw_device *dev = fw_parent_device(dg00x->unit);
 struct snd_firewire_get_info info;

 memset(&info, 0, sizeof(info));
 info.type = SNDRV_FIREWIRE_TYPE_DIGI00X;
 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_dg00x *dg00x)
{
 int err;

 spin_lock_irq(&dg00x->lock);

 if (dg00x->dev_lock_count == 0) {
  dg00x->dev_lock_count = -1;
  err = 0;
 } else {
  err = -EBUSY;
 }

 spin_unlock_irq(&dg00x->lock);

 return err;
}

static int hwdep_unlock(struct snd_dg00x *dg00x)
{
 int err;

 spin_lock_irq(&dg00x->lock);

 if (dg00x->dev_lock_count == -1) {
  dg00x->dev_lock_count = 0;
  err = 0;
 } else {
  err = -EBADFD;
 }

 spin_unlock_irq(&dg00x->lock);

 return err;
}

static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
{
 struct snd_dg00x *dg00x = hwdep->private_data;

 spin_lock_irq(&dg00x->lock);
 if (dg00x->dev_lock_count == -1)
  dg00x->dev_lock_count = 0;
 spin_unlock_irq(&dg00x->lock);

 return 0;
}

static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
     unsigned int cmd, unsigned long arg)
{
 struct snd_dg00x *dg00x = hwdep->private_data;

 switch (cmd) {
 case SNDRV_FIREWIRE_IOCTL_GET_INFO:
  return hwdep_get_info(dg00x, (void __user *)arg);
 case SNDRV_FIREWIRE_IOCTL_LOCK:
  return hwdep_lock(dg00x);
 case SNDRV_FIREWIRE_IOCTL_UNLOCK:
  return hwdep_unlock(dg00x);
 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_dg00x_create_hwdep_device(struct snd_dg00x *dg00x)
{
 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(dg00x->card, "Digi00x", 0, &hwdep);
 if (err < 0)
  return err;

 strscpy(hwdep->name, "Digi00x");
 hwdep->iface = SNDRV_HWDEP_IFACE_FW_DIGI00X;
 hwdep->ops = ops;
 hwdep->private_data = dg00x;
 hwdep->exclusive = true;

 return err;
}