greybus: connection: add no-flow-control connection flag

Add a no-flow-control connection flag, which is set for connection that
should not have any flow-control feature enabled.

This flag is specifically set for all connections to the legacy ES3
bootrom, and will also be used by the camera driver eventually.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/connection.c

@@ -183,6 +183,8 @@ _gb_connection_create(struct gb_host_device *hd, int hd_cport_id,
 	connection->bundle = bundle;
 	connection->handler = handler;
 	connection->flags = flags;
+	if (intf && (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES))
+		connection->flags |= GB_CONNECTION_FLAG_NO_FLOWCTRL;
 	connection->state = GB_CONNECTION_STATE_DISABLED;
 
 	atomic_set(&connection->op_cycle, 0);
@@ -338,11 +340,10 @@ gb_connection_svc_connection_create(struct gb_connection *connection)
 	intf = connection->intf;
 
 	/*
-	 * Enable either E2EFC or CSD, unless the interface does not support
-	 * any CPort features.
+	 * Enable either E2EFC or CSD, unless no flow control is requested.
 	 */
 	cport_flags = GB_SVC_CPORT_FLAG_CSV_N;
-	if (intf->quirks & GB_INTERFACE_QUIRK_NO_CPORT_FEATURES) {
+	if (gb_connection_flow_control_disabled(connection)) {
 		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N;
 	} else if (gb_connection_e2efc_enabled(connection)) {
 		cport_flags |= GB_SVC_CPORT_FLAG_CSD_N |

drivers/staging/greybus/connection.h

@@ -14,6 +14,7 @@
 #include <linux/kfifo.h>
 
 #define GB_CONNECTION_FLAG_CSD		BIT(0)
+#define GB_CONNECTION_FLAG_NO_FLOWCTRL	BIT(1)
 
 enum gb_connection_state {
 	GB_CONNECTION_STATE_INVALID	= 0,
@@ -88,6 +89,12 @@ static inline bool gb_connection_e2efc_enabled(struct gb_connection *connection)
 	return !(connection->flags & GB_CONNECTION_FLAG_CSD);
 }
 
+static inline bool
+gb_connection_flow_control_disabled(struct gb_connection *connection)
+{
+	return connection->flags & GB_CONNECTION_FLAG_NO_FLOWCTRL;
+}
+
 static inline void *gb_connection_get_data(struct gb_connection *connection)
 {
 	return connection->private;