switch-l4t-atf/readme.md

ARM Trusted Firmware - version 1.1
==================================

ARM Trusted Firmware provides a reference implementation of secure world
software for [ARMv8-A], including Exception Level 3 (EL3) software. This release
provides complete support for version 0.2 of the [PSCI] specification, initial
support for the new version 1.0 of that specification, and prototype support for
the Trusted Board Boot Requirements specification.

The intent is to provide a reference implementation of various ARM interface
standards, such as the Power State Coordination Interface ([PSCI]), Trusted
Board Boot Requirements (TBBR) and [Secure Monitor] [TEE-SMC] code. As far as
possible the code is designed for reuse or porting to other ARMv8-A model and
hardware platforms.

ARM will continue development in collaboration with interested parties to
provide a full reference implementation of PSCI, TBBR and Secure Monitor code
to the benefit of all developers working with ARMv8-A TrustZone technology.


License
-------

The software is provided under a BSD 3-Clause [license]. Certain source files
are derived from FreeBSD code: the original license is included in these
source files.


This Release
------------

This release is a limited functionality implementation of the Trusted Firmware.
It provides a suitable starting point for productization. Future versions will
contain new features, optimizations and quality improvements.

### Functionality

*   Prototype implementation of a subset of the Trusted Board Boot Requirements
    Platform Design Document (PDD). This includes packaging the various firmware
    images into a Firmware Image Package (FIP) to be loaded from non-volatile
    storage, and a prototype of authenticated boot using key certificates stored
    in the FIP.

*   Initializes the secure world (for example, exception vectors, control
    registers, GIC and interrupts for the platform), before transitioning into
    the normal world.

*   Supports both GICv2 and GICv3 initialization for use by normal world
    software.

*   Starts the normal world at the Exception Level and Register Width specified
    by the platform port. Typically this is AArch64 EL2 if available.

*   Handles SMCs (Secure Monitor Calls) conforming to the [SMC Calling
    Convention PDD] [SMCCC] using an EL3 runtime services framework.

*   Handles SMCs relating to the [Power State Coordination Interface PDD] [PSCI]
    for the Secondary CPU Boot, CPU Hotplug, CPU Idle and System Shutdown/Reset
    use-cases.

*   A Test Secure-EL1 Payload and Dispatcher to demonstrate Secure Monitor
    functionality such as world switching, EL1 context management and interrupt
    routing. This also demonstrates Secure-EL1 interaction with PSCI. Some of
    this functionality is provided in library form for re-use by other
    Secure-EL1 Payload Dispatchers.

*   Support for alternative Trusted Boot Firmware. Some platforms have their own
    Trusted Boot implementation and only require the Secure Monitor
    functionality provided by ARM Trusted Firmware.

*   Isolation of memory accessible by the secure world from the normal world
    through programming of a TrustZone controller.

*   Support for CPU specific reset sequences, power down sequences and register
    dumping during crash reporting. The CPU specific reset sequences include
    support for errata workarounds.

For a full description of functionality and implementation details, please
see the [Firmware Design] and supporting documentation. The [Change Log]
provides details of changes made since the last release.

### Platforms

This release of the Trusted Firmware has been tested on Revision B of the
[Juno ARM Development Platform] [Juno] with Version r0p0-00rel7 of the
[ARM SCP Firmware] [SCP download].

The Trusted Firmware has also been tested on the 64-bit Linux versions of the
following ARM [FVP]s:

*   `Foundation_Platform` (Version 9.1, Build 9.1.33)
*   `FVP_Base_AEMv8A-AEMv8A` (Version 6.2, Build 0.8.6202)
*   `FVP_Base_Cortex-A57x4-A53x4` (Version 6.2, Build 0.8.6202)
*   `FVP_Base_Cortex-A57x1-A53x1` (Version 6.2, Build 0.8.6202)
*   `FVP_Base_Cortex-A57x2-A53x4` (Version 6.2, Build 0.8.6202)

The Foundation FVP can be downloaded free of charge. The Base FVPs can be
licensed from ARM: see [www.arm.com/fvp] [FVP].

### Still to Come

*   Complete and more flexible Trusted Board Boot implementation.

*   Complete implementation of the [PSCI] v1.0 specification.

*   Support for alternative types of Secure-EL1 Payloads.

*   Extending the GICv3 support to the secure world.

*   Support for new System IP devices.

For a full list of detailed issues in the current code, please see the [Change
Log] and the [GitHub issue tracker].


Getting Started
---------------

Get the Trusted Firmware source code from
[GitHub](https://www.github.com/ARM-software/arm-trusted-firmware).

See the [User Guide] for instructions on how to install, build and use
the Trusted Firmware with the ARM [FVP]s.

See the [Firmware Design] for information on how the ARM Trusted Firmware works.

See the [Porting Guide] as well for information about how to use this
software on another ARMv8-A platform.

See the [Contributing Guidelines] for information on how to contribute to this
project and the [Acknowledgments] file for a list of contributors to the
project.

### Feedback and support

ARM welcomes any feedback on the Trusted Firmware. Please send feedback using
the [GitHub issue tracker].

ARM licensees may contact ARM directly via their partner managers.


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_Copyright (c) 2013-2015, ARM Limited and Contributors. All rights reserved._


[License]:                  ./license.md "BSD license for ARM Trusted Firmware"
[Contributing Guidelines]:  ./contributing.md "Guidelines for contributors"
[Acknowledgments]:          ./acknowledgements.md "Contributor acknowledgments"
[Change Log]:               ./docs/change-log.md
[User Guide]:               ./docs/user-guide.md
[Firmware Design]:          ./docs/firmware-design.md
[Porting Guide]:            ./docs/porting-guide.md

[ARMv8-A]:               http://www.arm.com/products/processors/armv8-architecture.php "ARMv8-A Architecture"
[FVP]:                   http://www.arm.com/fvp "ARM's Fixed Virtual Platforms"
[Juno]:                  http://www.arm.com/products/tools/development-boards/versatile-express/juno-arm-development-platform.php "Juno ARM Development Platform"
[SCP download]:          https://silver.arm.com/download/download.tm?pv=1764630
[PSCI]:                  http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf "Power State Coordination Interface PDD (ARM DEN 0022C)"
[SMCCC]:                 http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html "SMC Calling Convention PDD (ARM DEN 0028A)"
[TEE-SMC]:               http://www.arm.com/products/processors/technologies/trustzone/tee-smc.php "Secure Monitor and TEEs"
[GitHub issue tracker]:  https://github.com/ARM-software/tf-issues/issues