ALSA: fireworks: Add hwdep interface

This interface is designed for mixer/control application. To use hwdep
interface, the 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, 39 insertions, 0 deletions

diff --git a/sound/firewire/fireworks/fireworks_stream.c b/sound/firewire/fireworks/fireworks_stream.c
index 1860914a3e0f..eaab8f6bc8b6 100644
--- a/sound/firewire/fireworks/fireworks_stream.c
+++ b/sound/firewire/fireworks/fireworks_stream.c
@@ -331,3 +331,42 @@ void snd_efw_stream_destroy_duplex(struct snd_efw *efw)
 
 	mutex_unlock(&efw->mutex);
 }
+
+void snd_efw_stream_lock_changed(struct snd_efw *efw)
+{
+	efw->dev_lock_changed = true;
+	wake_up(&efw->hwdep_wait);
+}
+
+int snd_efw_stream_lock_try(struct snd_efw *efw)
+{
+	int err;
+
+	spin_lock_irq(&efw->lock);
+
+	/* user land lock this */
+	if (efw->dev_lock_count < 0) {
+		err = -EBUSY;
+		goto end;
+	}
+
+	/* this is the first time */
+	if (efw->dev_lock_count++ == 0)
+		snd_efw_stream_lock_changed(efw);
+	err = 0;
+end:
+	spin_unlock_irq(&efw->lock);
+	return err;
+}
+
+void snd_efw_stream_lock_release(struct snd_efw *efw)
+{
+	spin_lock_irq(&efw->lock);
+
+	if (WARN_ON(efw->dev_lock_count <= 0))
+		goto end;
+	if (--efw->dev_lock_count == 0)
+		snd_efw_stream_lock_changed(efw);
+end:
+	spin_unlock_irq(&efw->lock);
+}