Interface: Interface provided to NS side

These files provide a reference interface mplementation for integration
with OS running on the NS side. This has been tested to work with
RTX scheduler.
Modifications may be required while integrating other OS.

Change-Id: I4845584465c5df0bc574de31564a0789154c0dd5
Signed-off-by: Ashutosh Singh <ashutosh.singh@arm.com>
Co-Authored-By: Marc Moreno Berengue <marc.morenoberengue@arm.com>
Co-Authored-By: Antonio de Angelis <antonio.deangelis@arm.com>
diff --git a/interface/src/tfm_sst_api.c b/interface/src/tfm_sst_api.c
new file mode 100644
index 0000000..fb13ed0
--- /dev/null
+++ b/interface/src/tfm_sst_api.c
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+
+#include "tfm_sst_defs.h"
+#include "tfm_ns_lock.h"
+
+enum tfm_sst_err_t tfm_sst_get_handle(uint16_t asset_uuid, uint32_t* hdl)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_GET_HANDLE,
+                                    (uint32_t)asset_uuid,
+                                    (uint32_t)hdl,
+                                    0,
+                                    0);
+}
+
+enum tfm_sst_err_t tfm_sst_create(uint16_t asset_uuid)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_CREATE,
+                                    (uint32_t) asset_uuid,
+                                    0,
+                                    0,
+                                    0);
+}
+
+enum tfm_sst_err_t tfm_sst_get_attributes(uint32_t asset_handle,
+                                        struct tfm_sst_attribs_t* attrib_struct)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_GET_ATTRIBUTES,
+                                    (uint32_t)asset_handle,
+                                    (uint32_t)attrib_struct,
+                                    0,
+                                    0);
+}
+
+enum tfm_sst_err_t tfm_sst_read(uint32_t asset_handle, struct tfm_sst_buf_t* data)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_READ,
+                                    (uint32_t)asset_handle,
+                                    (uint32_t)data,
+                                    0,
+                                    0);
+}
+
+enum tfm_sst_err_t tfm_sst_write(uint32_t asset_handle, struct tfm_sst_buf_t* data)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_WRITE,
+                                    (uint32_t)asset_handle,
+                                    (uint32_t)data,
+                                    0,
+                                    0);
+}
+
+enum tfm_sst_err_t tfm_sst_delete(uint32_t asset_handle)
+{
+    return tfm_ns_lock_svc_dispatch(SVC_TFM_SST_DELETE,
+                                    (uint32_t)asset_handle,
+                                    0,
+                                    0,
+                                    0);
+}