diff --git a/lpc.h b/lpc.h
index cf91d42..eca78b2 100644
--- a/lpc.h
+++ b/lpc.h
@@ -4,6 +4,8 @@
 #ifndef LPC_H
 #define LPC_H
 
+struct mbox_context;
+
 int lpc_dev_init(struct mbox_context *context);
 void lpc_dev_free(struct mbox_context *context);
 int lpc_map_flash(struct mbox_context *context);