The general source code layout for mTower is typical for multiplatform projects. At the top level is the main makefile and a series of sub-directories that are described in detail below:

.
├── apps
│   ├── hello_world
│   │   ├── ca
│   │   │   └── hello_world_ns.c
│   │   ├── hello_world_ta.h
│   │   └── ta
│   │       └── hello_world_ta.c
│   ├── Kconfig
│   └── template
│       ├── ca
│       │   └── template_ns.c
│       ├── ta
│       │   └── template_ta.c
│       └── template_ta.h
├── arch
│   └── <arch-name>
│       └── <arch-family-name>
│           ├── include
│           └── src
│               └── <platform-name>
│                   ├── Kconfig
│                   ├── Makefile
│                   ├── nonsecure
│                   │   ├── FreeRTOSConfig.h
│                   │   ├── main_ns.c
│                   │   ├── Make.defs
│                   │   ├── Makefile
│                   │   ├── nonsecure.ld
│                   │   └── warn_err.c
│                   ├── partition_M2351.h
│                   └── secure
│                       ├── Makefile
│                       ├── ...
│                       ├── main.c
│                       ├── ...
│                       └── secure.ld
├── configs (platform configuration-specific files)
│   ├── <platform-name>
│   │   ├── defconfig
│   │   └── Make.defs
│   ├── ...
│   └── Makefile
├── docs (documentation files)
│   ├── images
│   │   └── ...
│   ├── ...
│   └── numaker_pfm_m2351.md
├── freertos
│   └── ...
├── include (common header files)
│   └── mtower
│       └── config.h
├── lib (temporary store for *.a files)
│   └── Makefile
├── libc (standard libc sources)
│   ├── Kconfig
│   ├── Makefile
│   ├── ...
│   └── strstr.c
├── tee_client
│   ├── libteec
│   │   ├── include
│   │   │   └── freertos
│   │   │       └── tee.h
│   │   └── src
│   │       └── tee_client_api.c
│   └── public
│       ├── tee_client_api_extensions.h
│       ├── tee_client_api.h
│       ├── teec_trace.h
│       └── tee_types.h
├── tee_internal
│   └── include
├── toolchain (specific toolchains)
│   ├── gcc-arm-none-eabi-6-2017-q1-update
├── tools (miscellaneous scripts and programs for build system)
│   ├── Makefile.host
│   ├── mkconfig.c
│   └── ...
├── AUTHORS (Authors and maintainers list)
├── COPYING (Extra license for usage of source code by third parties)
├── Doxyfile (doxygen configuration file)
├── Kconfig (Main kconfig-frontends file)
├── LICENSE (mTower license)
├── Makefile (Main Makefile)
├── README.md (Main doc file)
└── ReleaseNotes (Release description)

1. mTower/apps

Contains application examples.

2. mTower/arch

This directory contains several sub-directories, each containing architecture-specific logic. The task of porting mTower to a new processor consists of adding a new subdirectory under arch/ containing logic specific to the new architecture.

3. mTower/configs

The configs/ subdirectory contains configuration data for each board. These board-specific configurations plus the architecture-specific configurations in the arch/ subdirectory completely define a customized port of mTower.

4. mTower/docs

General documentation for the mTower resides in this directory.

5. mTower/freertos

Contains FreeRTOS source code.

6. mTower/include

This directory holds mTower header files.

/* Included Files */
#include <stdio.h>
#include <stdint.h>
#include "config.h"
#include "mtower.h"

Contains partial implementation of standard C language library.

7. mTower/tee_client

Contains implementation of GP TEE Client API specification.

8. mTower/tee_internal

Contains implementation of GP TEE Internal API specification.

9. mTower/toolchain

Toolchains necessary for building mTower for specific H/W platforms are downloaded into this directory. This directory is created automatically during execution of make toolchain command.

10. mTower/tools

Source code of tools used for building mTower itself for specific architectures.