1 files changed, 39 insertions, 0 deletions
diff --git a/sound/firewire/fireface/ff-stream.c b/sound/firewire/fireface/ff-stream.c
index 0ef6177aff20..78880922120e 100644
--- a/sound/firewire/fireface/ff-stream.c
+++ b/sound/firewire/fireface/ff-stream.c
@@ -241,3 +241,42 @@ void snd_ff_stream_update_duplex(struct snd_ff *ff)
 	fw_iso_resources_update(&ff->tx_resources);
 	fw_iso_resources_update(&ff->rx_resources);
 }
+
+void snd_ff_stream_lock_changed(struct snd_ff *ff)
+{
+	ff->dev_lock_changed = true;
+	wake_up(&ff->hwdep_wait);
+}
+
+int snd_ff_stream_lock_try(struct snd_ff *ff)
+{
+	int err;
+
+	spin_lock_irq(&ff->lock);
+
+	/* user land lock this */
+	if (ff->dev_lock_count < 0) {
+		err = -EBUSY;
+		goto end;
+	}
+
+	/* this is the first time */
+	if (ff->dev_lock_count++ == 0)
+		snd_ff_stream_lock_changed(ff);
+	err = 0;
+end:
+	spin_unlock_irq(&ff->lock);
+	return err;
+}
+
+void snd_ff_stream_lock_release(struct snd_ff *ff)
+{
+	spin_lock_irq(&ff->lock);
+
+	if (WARN_ON(ff->dev_lock_count <= 0))
+		goto end;
+	if (--ff->dev_lock_count == 0)
+		snd_ff_stream_lock_changed(ff);
+end:
+	spin_unlock_irq(&ff->lock);
+}