v4.19.13 snapshot.
diff --git a/sound/firewire/bebob/bebob_hwdep.c b/sound/firewire/bebob/bebob_hwdep.c
new file mode 100644
index 0000000..04c321e
--- /dev/null
+++ b/sound/firewire/bebob/bebob_hwdep.c
@@ -0,0 +1,198 @@
+/*
+ * bebob_hwdep.c - a part of driver for BeBoB based devices
+ *
+ * Copyright (c) 2013-2014 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+/*
+ * This codes give three functionality.
+ *
+ * 1.get firewire node infomation
+ * 2.get notification about starting/stopping stream
+ * 3.lock/unlock stream
+ */
+
+#include "bebob.h"
+
+static long
+hwdep_read(struct snd_hwdep *hwdep, char __user *buf,  long count,
+	   loff_t *offset)
+{
+	struct snd_bebob *bebob = hwdep->private_data;
+	DEFINE_WAIT(wait);
+	union snd_firewire_event event;
+
+	spin_lock_irq(&bebob->lock);
+
+	while (!bebob->dev_lock_changed) {
+		prepare_to_wait(&bebob->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+		spin_unlock_irq(&bebob->lock);
+		schedule();
+		finish_wait(&bebob->hwdep_wait, &wait);
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+		spin_lock_irq(&bebob->lock);
+	}
+
+	memset(&event, 0, sizeof(event));
+	if (bebob->dev_lock_changed) {
+		event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+		event.lock_status.status = (bebob->dev_lock_count > 0);
+		bebob->dev_lock_changed = false;
+
+		count = min_t(long, count, sizeof(event.lock_status));
+	}
+
+	spin_unlock_irq(&bebob->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_bebob *bebob = hwdep->private_data;
+	__poll_t events;
+
+	poll_wait(file, &bebob->hwdep_wait, wait);
+
+	spin_lock_irq(&bebob->lock);
+	if (bebob->dev_lock_changed)
+		events = EPOLLIN | EPOLLRDNORM;
+	else
+		events = 0;
+	spin_unlock_irq(&bebob->lock);
+
+	return events;
+}
+
+static int
+hwdep_get_info(struct snd_bebob *bebob, void __user *arg)
+{
+	struct fw_device *dev = fw_parent_device(bebob->unit);
+	struct snd_firewire_get_info info;
+
+	memset(&info, 0, sizeof(info));
+	info.type = SNDRV_FIREWIRE_TYPE_BEBOB;
+	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]);
+	strlcpy(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_bebob *bebob)
+{
+	int err;
+
+	spin_lock_irq(&bebob->lock);
+
+	if (bebob->dev_lock_count == 0) {
+		bebob->dev_lock_count = -1;
+		err = 0;
+	} else {
+		err = -EBUSY;
+	}
+
+	spin_unlock_irq(&bebob->lock);
+
+	return err;
+}
+
+static int
+hwdep_unlock(struct snd_bebob *bebob)
+{
+	int err;
+
+	spin_lock_irq(&bebob->lock);
+
+	if (bebob->dev_lock_count == -1) {
+		bebob->dev_lock_count = 0;
+		err = 0;
+	} else {
+		err = -EBADFD;
+	}
+
+	spin_unlock_irq(&bebob->lock);
+
+	return err;
+}
+
+static int
+hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+{
+	struct snd_bebob *bebob = hwdep->private_data;
+
+	spin_lock_irq(&bebob->lock);
+	if (bebob->dev_lock_count == -1)
+		bebob->dev_lock_count = 0;
+	spin_unlock_irq(&bebob->lock);
+
+	return 0;
+}
+
+static int
+hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
+	    unsigned int cmd, unsigned long arg)
+{
+	struct snd_bebob *bebob = hwdep->private_data;
+
+	switch (cmd) {
+	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+		return hwdep_get_info(bebob, (void __user *)arg);
+	case SNDRV_FIREWIRE_IOCTL_LOCK:
+		return hwdep_lock(bebob);
+	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+		return hwdep_unlock(bebob);
+	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_bebob_create_hwdep_device(struct snd_bebob *bebob)
+{
+	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(bebob->card, "BeBoB", 0, &hwdep);
+	if (err < 0)
+		goto end;
+	strcpy(hwdep->name, "BeBoB");
+	hwdep->iface = SNDRV_HWDEP_IFACE_FW_BEBOB;
+	hwdep->ops = ops;
+	hwdep->private_data = bebob;
+	hwdep->exclusive = true;
+end:
+	return err;
+}
+