sound/firewire/fireface/ff-hwdep.c

   1 /*
   2  * ff-hwdep.c - a part of driver for RME Fireface series
   3  *
   4  * Copyright (c) 2015-2017 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 "ff.h"
  18
  19 static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
  20                        loff_t *offset)
  21 {
  22         struct snd_ff *ff = hwdep->private_data;
  23         DEFINE_WAIT(wait);
  24         union snd_firewire_event event;
  25
  26         spin_lock_irq(&ff->lock);
  27
  28         while (!ff->dev_lock_changed) {
  29                 prepare_to_wait(&ff->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
  30                 spin_unlock_irq(&ff->lock);
  31                 schedule();
  32                 finish_wait(&ff->hwdep_wait, &wait);
  33                 if (signal_pending(current))
  34                         return -ERESTARTSYS;
  35                 spin_lock_irq(&ff->lock);
  36         }
  37
  38         memset(&event, 0, sizeof(event));
  39         if (ff->dev_lock_changed) {
  40                 event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
  41                 event.lock_status.status = (ff->dev_lock_count > 0);
  42                 ff->dev_lock_changed = false;
  43
  44                 count = min_t(long, count, sizeof(event.lock_status));
  45         }
  46
  47         spin_unlock_irq(&ff->lock);
  48
  49         if (copy_to_user(buf, &event, count))
  50                 return -EFAULT;
  51
  52         return count;
  53 }
  54
  55 static __poll_t hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
  56                                poll_table *wait)
  57 {
  58         struct snd_ff *ff = hwdep->private_data;
  59         __poll_t events;
  60
  61         poll_wait(file, &ff->hwdep_wait, wait);
  62
  63         spin_lock_irq(&ff->lock);
  64         if (ff->dev_lock_changed)
  65                 events = EPOLLIN | EPOLLRDNORM;
  66         else
  67                 events = 0;
  68         spin_unlock_irq(&ff->lock);
  69
  70         return events;
  71 }
  72
  73 static int hwdep_get_info(struct snd_ff *ff, void __user *arg)
  74 {
  75         struct fw_device *dev = fw_parent_device(ff->unit);
  76         struct snd_firewire_get_info info;
  77
  78         memset(&info, 0, sizeof(info));
  79         info.type = SNDRV_FIREWIRE_TYPE_FIREFACE;
  80         info.card = dev->card->index;
  81         *(__be32 *)&info.guid[0] = cpu_to_be32(dev->config_rom[3]);
  82         *(__be32 *)&info.guid[4] = cpu_to_be32(dev->config_rom[4]);
  83         strlcpy(info.device_name, dev_name(&dev->device),
  84                 sizeof(info.device_name));
  85
  86         if (copy_to_user(arg, &info, sizeof(info)))
  87                 return -EFAULT;
  88
  89         return 0;
  90 }
  91
  92 static int hwdep_lock(struct snd_ff *ff)
  93 {
  94         int err;
  95
  96         spin_lock_irq(&ff->lock);
  97
  98         if (ff->dev_lock_count == 0) {
  99                 ff->dev_lock_count = -1;
 100                 err = 0;
 101         } else {
 102                 err = -EBUSY;
 103         }
 104
 105         spin_unlock_irq(&ff->lock);
 106
 107         return err;
 108 }
 109
 110 static int hwdep_unlock(struct snd_ff *ff)
 111 {
 112         int err;
 113
 114         spin_lock_irq(&ff->lock);
 115
 116         if (ff->dev_lock_count == -1) {
 117                 ff->dev_lock_count = 0;
 118                 err = 0;
 119         } else {
 120                 err = -EBADFD;
 121         }
 122
 123         spin_unlock_irq(&ff->lock);
 124
 125         return err;
 126 }
 127
 128 static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
 129 {
 130         struct snd_ff *ff = hwdep->private_data;
 131
 132         spin_lock_irq(&ff->lock);
 133         if (ff->dev_lock_count == -1)
 134                 ff->dev_lock_count = 0;
 135         spin_unlock_irq(&ff->lock);
 136
 137         return 0;
 138 }
 139
 140 static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
 141                        unsigned int cmd, unsigned long arg)
 142 {
 143         struct snd_ff *ff = hwdep->private_data;
 144
 145         switch (cmd) {
 146         case SNDRV_FIREWIRE_IOCTL_GET_INFO:
 147                 return hwdep_get_info(ff, (void __user *)arg);
 148         case SNDRV_FIREWIRE_IOCTL_LOCK:
 149                 return hwdep_lock(ff);
 150         case SNDRV_FIREWIRE_IOCTL_UNLOCK:
 151                 return hwdep_unlock(ff);
 152         default:
 153                 return -ENOIOCTLCMD;
 154         }
 155 }
 156
 157 #ifdef CONFIG_COMPAT
 158 static int hwdep_compat_ioctl(struct snd_hwdep *hwdep, struct file *file,
 159                               unsigned int cmd, unsigned long arg)
 160 {
 161         return hwdep_ioctl(hwdep, file, cmd,
 162                            (unsigned long)compat_ptr(arg));
 163 }
 164 #else
 165 #define hwdep_compat_ioctl NULL
 166 #endif
 167
 168 int snd_ff_create_hwdep_devices(struct snd_ff *ff)
 169 {
 170         static const struct snd_hwdep_ops hwdep_ops = {
 171                 .read           = hwdep_read,
 172                 .release        = hwdep_release,
 173                 .poll           = hwdep_poll,
 174                 .ioctl          = hwdep_ioctl,
 175                 .ioctl_compat   = hwdep_compat_ioctl,
 176         };
 177         struct snd_hwdep *hwdep;
 178         int err;
 179
 180         err = snd_hwdep_new(ff->card, ff->card->driver, 0, &hwdep);
 181         if (err < 0)
 182                 return err;
 183
 184         strcpy(hwdep->name, ff->card->driver);
 185         hwdep->iface = SNDRV_HWDEP_IFACE_FW_FIREFACE;
 186         hwdep->ops = hwdep_ops;
 187         hwdep->private_data = ff;
 188         hwdep->exclusive = true;
 189
 190         return 0;
 191 }