mailbox: Introduce K3 Secure Proxy Driver

Secure Proxy module manages hardware threads that are meant
for communication between the processor entities. Adding
support for this driver.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>

include/linux/soc/ti/k3-sec-proxy.h

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Texas Instruments' K3 Secure proxy
+ *
+ * Copyright (C) 2017-2018 Texas Instruments Incorporated - http://www.ti.com/
+ *	Lokesh Vutla <lokeshvutla@ti.com>
+ *
+ */
+
+#ifndef K3_SEC_PROXY_H
+#define K3_SEC_PROXY_H
+
+/**
+ * struct k3_sec_proxy_msg - Secure proxy message structure
+ * @len: Length of data in the Buffer
+ * @buf: Buffer pointer
+ *
+ * This is the structure for data used in mbox_send() and mbox_recv().
+ */
+struct k3_sec_proxy_msg {
+	size_t len;
+	u32 *buf;
+};
+
+#endif /* K3_SEC_PROXY_H */