sound/firewire/tascam/tascam-hwdep.c

   1 /*
   2  * tascam-hwdep.c - a part of driver for TASCAM FireWire series
   3  *
   4  * Copyright (c) 2015 Takashi Sakamoto
   5  *
   6  * Licensed under the terms of the GNU General Public License, version 2.
   7  */
   8
   9 /*
  10  * This codes give three functionality.
  11  *
  12  * 1.get firewire node information
  13  * 2.get notification about starting/stopping stream
  14  * 3.lock/unlock stream
  15  */
  16
  17 #include "tascam.h"
  18
  19 static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
  20                        loff_t *offset)
  21 {
  22         struct snd_tscm *tscm = hwdep->private_data;
  23         DEFINE_WAIT(wait);
  24         union snd_firewire_event event = {
  25                 .lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS,
  26         };
  27
  28         spin_lock_irq(&tscm->lock);
  29
  30         while (!tscm->dev_lock_changed) {
  31                 prepare_to_wait(&tscm->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
  32                 spin_unlock_irq(&tscm->lock);
  33                 schedule();
  34                 finish_wait(&tscm->hwdep_wait, &wait);
  35                 if (signal_pending(current))
  36                         return -ERESTARTSYS;
  37                 spin_lock_irq(&tscm->lock);
  38         }
  39
  40         event.lock_status.status = (tscm->dev_lock_count > 0);
  41         tscm->dev_lock_changed = false;
  42
  43         spin_unlock_irq(&tscm->lock);
  44
  45         count = min_t(long, count, sizeof(event.lock_status));
  46
  47         if (copy_to_user(buf, &event, count))
  48                 return -EFAULT;
  49
  50         return count;
  51 }
  52
  53 static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
  54                                poll_table *wait)
  55 {
  56         struct snd_tscm *tscm = hwdep->private_data;
  57         __poll_t events;
  58
  59         poll_wait(file, &tscm->hwdep_wait, wait);
  60
  61         spin_lock_irq(&tscm->lock);
  62         if (tscm->dev_lock_changed)
  63                 events = EPOLLIN | EPOLLRDNORM;
  64         else
  65                 events = 0;
  66         spin_unlock_irq(&tscm->lock);
  67
  68         return events;
  69 }
  70
  71 static int hwdep_get_info(struct snd_tscm *tscm, void __user *arg)
  72 {
  73         struct fw_device *dev = fw_parent_device(tscm->unit);
  74         struct snd_firewire_get_info info;
  75
  76         memset(&info, 0, sizeof(info));
  77         info.type = SNDRV_FIREWIRE_TYPE_TASCAM;
  78         info.card = dev->card->index;
  79         *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
  80         *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
  81         strlcpy(info.device_name, dev_name(&dev->device),
  82                 sizeof(info.device_name));
  83
  84         if (copy_to_user(arg, &info, sizeof(info)))
  85                 return -EFAULT;
  86
  87         return 0;
  88 }
  89
  90 static int hwdep_lock(struct snd_tscm *tscm)
  91 {
  92         int err;
  93
  94         spin_lock_irq(&tscm->lock);
  95
  96         if (tscm->dev_lock_count == 0) {
  97                 tscm->dev_lock_count = -1;
  98                 err = 0;
  99         } else {
 100                 err = -EBUSY;
 101         }
 102
 103         spin_unlock_irq(&tscm->lock);
 104
 105         return err;
 106 }
 107
 108 static int hwdep_unlock(struct snd_tscm *tscm)
 109 {
 110         int err;
 111
 112         spin_lock_irq(&tscm->lock);
 113
 114         if (tscm->dev_lock_count == -1) {
 115                 tscm->dev_lock_count = 0;
 116                 err = 0;
 117         } else {
 118                 err = -EBADFD;
 119         }
 120
 121         spin_unlock_irq(&tscm->lock);
 122
 123         return err;
 124 }
 125
 126 static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
 127 {
 128         struct snd_tscm *tscm = hwdep->private_data;
 129
 130         spin_lock_irq(&tscm->lock);
 131         if (tscm->dev_lock_count == -1)
 132                 tscm->dev_lock_count = 0;
 133         spin_unlock_irq(&tscm->lock);
 134
 135         return 0;
 136 }
 137
 138 static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
 139             unsigned int cmd, unsigned long arg)
 140 {
 141         struct snd_tscm *tscm = hwdep->private_data;
 142
 143         switch (cmd) {
 144         case SNDRV_FIREWIRE_IOCTL_GET_INFO:
 145                 return hwdep_get_info(tscm, (void __user *)arg);
 146         case SNDRV_FIREWIRE_IOCTL_LOCK:
 147                 return hwdep_lock(tscm);
 148         case SNDRV_FIREWIRE_IOCTL_UNLOCK:
 149                 return hwdep_unlock(tscm);
 150         default:
 151                 return -ENOIOCTLCMD;
 152         }
 153 }
 154
 155 #ifdef CONFIG_COMPAT
 156 static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
 157                               unsigned int cmd, unsigned long arg)
 158 {
 159         return hwdep_ioctl(hwdep, file, cmd,
 160                            (unsigned long)compat_ptr(arg));
 161 }
 162 #else
 163 #define hwdep_compat_ioctl NULL
 164 #endif
 165
 166 int snd_tscm_create_hwdep_device(struct snd_tscm *tscm)
 167 {
 168         static const struct snd_hwdep_ops ops = {
 169                 .read           = hwdep_read,
 170                 .release        = hwdep_release,
 171                 .poll           = hwdep_poll,
 172                 .ioctl          = hwdep_ioctl,
 173                 .ioctl_compat   = hwdep_compat_ioctl,
 174         };
 175         struct snd_hwdep *hwdep;
 176         int err;
 177
 178         err = snd_hwdep_new(tscm->card, "Tascam", 0, &hwdep);
 179         if (err < 0)
 180                 return err;
 181
 182         strcpy(hwdep->name, "Tascam");
 183         hwdep->iface = SNDRV_HWDEP_IFACE_FW_TASCAM;
 184         hwdep->ops = ops;
 185         hwdep->private_data = tscm;
 186         hwdep->exclusive = true;
 187
 188         return err;
 189 }