arm: omap-common: add secure rom call API for secure devices

Adds a generic C-callable API for making secure ROM calls on OMAP and
OMAP-compatible devices. This API provides the important function of
flushing the ROM call arguments to memory from the cache, so that the
secure world will have a coherent view of those arguments. Then is
simply calls the omap_smc_sec routine.

Signed-off-by: Daniel Allred <d-allred@ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/include/asm/omap_sec_common.h

@@ -0,0 +1,21 @@
+/*
+ * (C) Copyright 2016
+ * Texas Instruments, <www.ti.com>
+ *
+ * Andreas Dannenberg <dannenberg@ti.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+#ifndef	_OMAP_SEC_COMMON_H_
+#define	_OMAP_SEC_COMMON_H_
+
+#include <common.h>
+
+/*
+ * Invoke secure ROM API on high-security (HS) device variants. It formats
+ * the variable argument list into the format expected by the ROM code before
+ * triggering the actual low-level smc entry.
+ */
+u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);
+
+#endif /* _OMAP_SEC_COMMON_H_ */