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+###############################
+Details for the platform folder
+###############################
+
+.. Warning::
+
+    This folder and subfolders, especially the target folder, are likely to be
+    refactored and updated to improve the overall structure of dependencies.
+
+**************************
+Interfacing with TF-M core
+**************************
+
+platformext/target/tfm_peripherals_def.h
+========================================
+This file should enumerate the hardware peripherals that are available for TF-M
+on the platform. The name of the peripheral used by a service is set in its
+manifest file. The platform have to provide a macro for each of the provided
+peripherals, that is substituted to a pointer to type
+``struct tfm_spm_partition_platform_data_t``. The memory that the pointer points
+to is allocated by the platform code. The pointer gets stored in the partitions
+database in SPM, and it is provided to the SPM HAL functions.
+
+Peripherals currently used by the services in TF-M
+--------------------------------------------------
+- ``TFM_PERIPHERAL_FPGA_IO`` - FPGA system control and I/O
+- ``TFM_PERIPHERAL_UART1``-  UART1
+
+.. Note::
+
+    If a platform doesn't support a peripheral, that is used by a service, then
+    the service cannot be used on the given platform. Using a peripheral in
+    TF-M that is not supported by the platform results in compile error.
+
+platform/include/tfm_spm_hal.h
+==============================
+This file contains the declarations of functions that a platform implementation
+has to provide for TF-M. For details see the comments in the file.
+
+secure_fw/core/tfm_platform_core_api.h
+======================================
+This file contains declarations of functions that can be or have to be called
+from platform implementations. For details see the comments in the file.
+
+***********
+Sub-folders
+***********
+
+include
+=======
+This folder contains the interfaces that TF-M expects every target to provide.
+The code in this folder is created as a part of the TF-M project therefore it
+adheres to the BSD 3.0 license.
+
+ext
+===
+This folder contains code that has been imported from other projects so it may
+have licenses other than the BSD 3.0 used by the TF-M project.
+
+Please see the :doc:`readme file the ext folder <ext/readme>` for details.
+
+--------------
+
+*Copyright (c) 2017-2019, Arm Limited. All rights reserved.*