greybus: introduce a connection abstraction

Within a UniPro network a pair of CPorts can be linked to form a
UniPro Connection.  This patch creates a new abstraction to
represent an AP CPort that is connected with a CPort used by a
function within a Greybus module.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/staging/greybus/connection.c b/drivers/staging/greybus/connection.c
new file mode 100644
index 000000000000..113c98542858
--- /dev/null
+++ b/drivers/staging/greybus/connection.c
@@ -0,0 +1,48 @@
+/*
+ * Greybus connections
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+
+/*
+ * Set up a Greybus connection, representing the bidirectional link
+ * between a CPort on a (local) Greybus host device and a CPort on
+ * another Greybus module.
+ *
+ * Returns a pointer to the new connection if successful, or a null
+ * pointer otherwise.
+ */
+struct gb_connection *gb_connection_create(struct greybus_host_device *hd,
+				u16 cport_id, struct gb_function *function)
+{
+	struct gb_connection *connection;
+
+	connection = kzalloc(sizeof(*connection), GFP_KERNEL);
+	if (!connection)
+		return NULL;
+
+	connection->hd = hd;			/* XXX refcount? */
+	connection->cport_id = cport_id;
+	connection->function = function;	/* XXX refcount? */
+
+	return connection;
+}
+
+/*
+ * Tear down a previously set up connection.
+ */
+void gb_connection_destroy(struct gb_connection *connection)
+{
+	if (WARN_ON(!connection))
+		return;
+
+	/* XXX Need to wait for any outstanding requests to complete */
+
+	/* kref_put(function); */
+	/* kref_put(hd); */
+	kfree(connection);
+}