2 files changed, 19 insertions, 0 deletions

diff --git a/sound/firewire/cmp.c b/sound/firewire/cmp.c
index 9da40d9e79da..d31a403ac539 100644
--- a/sound/firewire/cmp.c
+++ b/sound/firewire/cmp.c
@@ -152,6 +152,24 @@ int cmp_connection_init(struct cmp_connection *c,
 EXPORT_SYMBOL(cmp_connection_init);
 
 /**
+ * cmp_connection_check_used - check connection is already esablished or not
+ * @c: the connection manager to be checked
+ */
+int cmp_connection_check_used(struct cmp_connection *c, bool *used)
+{
+        __be32 pcr;
+        int err;
+
+        err = snd_fw_transaction(
+                        c->resources.unit, TCODE_READ_QUADLET_REQUEST,
+                        pcr_address(c), &pcr, 4, 0);
+        if (err >= 0)
+                *used = (pcr & cpu_to_be32(PCR_BCAST_CONN | PCR_P2P_CONN_MASK));
+        return err;
+}
+EXPORT_SYMBOL(cmp_connection_check_used);
+
+/**
  * cmp_connection_destroy - free connection manager resources
  * @c: the connection manager
  */
diff --git a/sound/firewire/cmp.h b/sound/firewire/cmp.h
index 9b58448d5791..ebcb48484fca 100644
--- a/sound/firewire/cmp.h
+++ b/sound/firewire/cmp.h
@@ -38,6 +38,7 @@ int cmp_connection_init(struct cmp_connection *connection,
                         struct fw_unit *unit,
                         enum cmp_direction direction,
                         unsigned int pcr_index);
+int cmp_connection_check_used(struct cmp_connection *connection, bool *used);
 void cmp_connection_destroy(struct cmp_connection *connection);
 
 int cmp_connection_establish(struct cmp_connection *connection,