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+# Structure of files
+
+## Top level directories
+Directory | Description
+:---------|:------------
+/core	  | Files that are only used building TEE Core
+/lib	  | Files that are used both when building TEE Core and TAs
+/ta	  | Files that are only used when building TAs
+/mk	  | Makefiles supporting the build system
+/tmp-stuff| Temporary stuff that will be removed before the final commit is made
+/scripts  | Helper scripts for miscellaneous tasks
+/out	  | Created when building unless a different out directory is specified with O=... on the command line
+
+## Structure of /core
+Directory | Description
+:---------|:------------
+/arch	  | Architecture and platform specific files
+/lib	  | Generic libraries that are likely to be replaced in a final product
+/mm	  | Generic memory management, currently empty
+/tee	  | Generic TEE files
+
+## Structure of /core/arch
+Directory | Description
+:---------|:------------
+/arm	  | ARMv7 and Aarch32 specific architecture and platform specific files
+/user_mode| Linux used space specific files when debugging TEE Core as a user space process, only used for some development
+
+## Structure of /core/arch/arm
+Directory | Description
+:---------|:------------
+/include  | Include files used in rest of TEE core but not in any supporting libraries
+/kern	  | Low level and core parts of TEE Core
+/mm	  | Memory management
+/tee	  | TEE files
+/sm	  | Secure Monitor
+/plat-foo | Specific files for the 'foo' platform
+
+## Structure of /core/arch/arm/include
+Directory | Description
+:---------|:------------
+/kern	  | Include files exposing API for /core/arch/arm/kern files
+/kta	  | Include files exposing the KTA API that is mainly used by kernel TAs
+/mm	  | Include files exposing API for /core/arch/arm/mm files
+/rom	  | Old ROM files that should be removed before going public
+/sm	  | Include files exposing API for Secure Monitor
+
+## Structure of /core/lib/lib{crypto,sla}
+Directory | Description
+:---------|:------------
+/	  | Source files for the library
+/include  | Include files exposing the API of the library
+
+## Structure of /lib/libutils
+Directory | Description
+:---------|:------------
+/	  | Source file for the library
+/arch	  | Architecture specific source files
+/arch/arm | ARMv7 and Aarch32 specific source files
+/arch/arm/include | ARMv7 and Aarch32 specific include files
+/include  | Include files exposing the API of the library