ALSA: firewire-motu: add hwdep interface

This commit adds hwdep interface so as the other sound drivers for units
on IEEE 1394 bus have.

This interface is designed for mixer/control applications. By using this
interface, an application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 192 insertions, 0 deletions

diff --git a/sound/firewire/motu/motu-hwdep.c b/sound/firewire/motu/motu-hwdep.c
new file mode 100644
index 000000000000..e795a5219a21
--- /dev/null
+++ b/sound/firewire/motu/motu-hwdep.c
@@ -0,0 +1,192 @@
+/*
+ * motu-hwdep.c - a part of driver for MOTU FireWire series
+ *
+ * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+/*
+ * This codes have five functionalities.
+ *
+ * 1.get information about firewire node
+ * 2.get notification about starting/stopping stream
+ * 3.lock/unlock streaming
+ *
+ */
+
+#include "motu.h"
+
+static long hwdep_read(struct snd_hwdep *hwdep, char __user *buf, long count,
+		       loff_t *offset)
+{
+	struct snd_motu *motu = hwdep->private_data;
+	DEFINE_WAIT(wait);
+	union snd_firewire_event event;
+
+	spin_lock_irq(&motu->lock);
+
+	while (!motu->dev_lock_changed) {
+		prepare_to_wait(&motu->hwdep_wait, &wait, TASK_INTERRUPTIBLE);
+		spin_unlock_irq(&motu->lock);
+		schedule();
+		finish_wait(&motu->hwdep_wait, &wait);
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+		spin_lock_irq(&motu->lock);
+	}
+
+	memset(&event, 0, sizeof(event));
+	if (motu->dev_lock_changed) {
+		event.lock_status.type = SNDRV_FIREWIRE_EVENT_LOCK_STATUS;
+		event.lock_status.status = (motu->dev_lock_count > 0);
+		motu->dev_lock_changed = false;
+
+		count = min_t(long, count, sizeof(event.lock_status));
+	}
+
+	spin_unlock_irq(&motu->lock);
+
+	if (copy_to_user(buf, &event, count))
+		return -EFAULT;
+
+	return count;
+}
+
+static unsigned int hwdep_poll(struct snd_hwdep *hwdep, struct file *file,
+			       poll_table *wait)
+{
+	struct snd_motu *motu = hwdep->private_data;
+	unsigned int events;
+
+	poll_wait(file, &motu->hwdep_wait, wait);
+
+	spin_lock_irq(&motu->lock);
+	if (motu->dev_lock_changed)
+		events = POLLIN | POLLRDNORM;
+	else
+		events = 0;
+	spin_unlock_irq(&motu->lock);
+
+	return events | POLLOUT;
+}
+
+static int hwdep_get_info(struct snd_motu *motu, void __user *arg)
+{
+	struct fw_device *dev = fw_parent_device(motu->unit);
+	struct snd_firewire_get_info info;
+
+	memset(&info, 0, sizeof(info));
+	info.type = SNDRV_FIREWIRE_TYPE_MOTU;
+	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_motu *motu)
+{
+	int err;
+
+	spin_lock_irq(&motu->lock);
+
+	if (motu->dev_lock_count == 0) {
+		motu->dev_lock_count = -1;
+		err = 0;
+	} else {
+		err = -EBUSY;
+	}
+
+	spin_unlock_irq(&motu->lock);
+
+	return err;
+}
+
+static int hwdep_unlock(struct snd_motu *motu)
+{
+	int err;
+
+	spin_lock_irq(&motu->lock);
+
+	if (motu->dev_lock_count == -1) {
+		motu->dev_lock_count = 0;
+		err = 0;
+	} else {
+		err = -EBADFD;
+	}
+
+	spin_unlock_irq(&motu->lock);
+
+	return err;
+}
+
+static int hwdep_release(struct snd_hwdep *hwdep, struct file *file)
+{
+	struct snd_motu *motu = hwdep->private_data;
+
+	spin_lock_irq(&motu->lock);
+	if (motu->dev_lock_count == -1)
+		motu->dev_lock_count = 0;
+	spin_unlock_irq(&motu->lock);
+
+	return 0;
+}
+
+static int hwdep_ioctl(struct snd_hwdep *hwdep, struct file *file,
+	    unsigned int cmd, unsigned long arg)
+{
+	struct snd_motu *motu = hwdep->private_data;
+
+	switch (cmd) {
+	case SNDRV_FIREWIRE_IOCTL_GET_INFO:
+		return hwdep_get_info(motu, (void __user *)arg);
+	case SNDRV_FIREWIRE_IOCTL_LOCK:
+		return hwdep_lock(motu);
+	case SNDRV_FIREWIRE_IOCTL_UNLOCK:
+		return hwdep_unlock(motu);
+	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_motu_create_hwdep_device(struct snd_motu *motu)
+{
+	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(motu->card, motu->card->driver, 0, &hwdep);
+	if (err < 0)
+		return err;
+
+	strcpy(hwdep->name, "MOTU");
+	hwdep->iface = SNDRV_HWDEP_IFACE_FW_MOTU;
+	hwdep->ops = ops;
+	hwdep->private_data = motu;
+	hwdep->exclusive = true;
+
+	return 0;
+}