v4.19.13 snapshot.
diff --git a/drivers/tty/n_tracesink.h b/drivers/tty/n_tracesink.h
new file mode 100644
index 0000000..1b84633
--- /dev/null
+++ b/drivers/tty/n_tracesink.h
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * n_tracesink.h - Kernel driver API to route trace data in kernel space.
+ *
+ * Copyright (C) Intel 2011
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The PTI (Parallel Trace Interface) driver directs trace data routed from
+ * various parts in the system out through the Intel Penwell PTI port and
+ * out of the mobile device for analysis with a debugging tool
+ * (Lauterbach, Fido). This is part of a solution for the MIPI P1149.7,
+ * compact JTAG, standard.
+ *
+ * This header file is used by n_tracerouter to be able to send the
+ * data of it's tty port to the tty port this module sits. This
+ * mechanism can also be used independent of the PTI module.
+ *
+ */
+
+#ifndef N_TRACESINK_H_
+#define N_TRACESINK_H_
+
+void n_tracesink_datadrain(u8 *buf, int count);
+
+#endif