Virtual Prototyping Platform (VPP)

Please note that the VPP project will become part of a DSDP Incubator project in the near future.

Introduction

The Virtual Prototyping Platform (VPP) project is a proposed open source project under the Device Software Development Platform Project. VPP is intended to collect a number of smaller technologies together that, when combined, will enable Eclipse to be used for the tasks associated with constructing, debugging, visualizing, analyzing, and using (models of) systems constructed from components that may be based on hardware or software, or a combination of both.

This proposal is in the Project Proposal Phase (as defined in the Eclipse Development Process document) and is written to declare its intent and scope. This proposal is written to solicit additional participation and input from the Eclipse community. You are invited to comment on and/or join the project. Please send all feedback to the http://www.eclipse.org/newsportal/thread.php?group=eclipse.dsdp.vpp newsgroup.

Background

Today, complex systems are no longer designed monolithically, but rather as amalgamations (at the system level) of complex interconnected components, each of which may consist of both hardware and hardware dependent software components. In order to design such systems, often models are used. They can be used to explore potential implementations (in terms of hardware, software, or the division between hardware and software), enable early software development on top of the system "platform," or indeed as a reference model that can be used for verification. The models can encompass both hardware and software components. Models can be written to be more or less faithful to the final implementation, both in terms of their functionality, and in terms of the "meta" information that they model (for instance execution time or power consumption).

Functional accuracy can range markedly, from very little (pure traffic generators), through partially accurate models (which may not model some specific features of a hardware implementation, which may or may not be visible to a programmer), to models that are totally functionally accurate. Further more, models may be specifically designed to "stress" software components, often for the purpose of assisting in debug, and ensuring software correctness. This level of activity is often referred to as the "Electronic System Level" or ESL. ESL Design activity often occurs prior to or at the point of making a split between hardware and software, which is often recognized as a highly influential point in the design process. The wide range of uses that ESL models are put to means that there are many "views" of them that are appropriate.

These models may be of components destined to for implementation in hardware or in software. The models constructed (and debugged) in this way then provide a starting point for the development of hardware dependent software and the hardware itself. While the processor-centric view of a system is addressed by other projects within Eclipse, and other projects focus on connections with hardware, this project focuses on how to construct, connect, debug, analyze, visualize and use models (of virtual prototype components destined for implementation in hardware, or software) to Eclipse. The language used for the ESL Design activity is predominantly (though not exclusively) SystemC. SystemC is a language implemented as a C++ library, so it shares many of the debug requirements of C++ itself. However, there are additional views of a SystemC model that are useful to the designer (for instance, SystemC keyword highlighting, model connectivity diagrams etc). It is expected that the VPP will cover other languages over time that are relevant to ESL (e.g. System Verilog). Once SystemC models are debugged, and executable, they can be run either using a freely available SystemC library implementation (provided by the Open SystemC Initiative), or one of the many proprietary simulators. In either case, a model may wish to interact with the user, for a number of reasons:

• Configuration
• Run time Control
• User input
• Visualization (output)
• Analysis and Profiling

In each case, mechanisms will be required in Eclipse to support this user interaction.

Use Case Scenarios

The use cases for VPP can be divided into two main categories, those associated with initial model creation, and those associated with model execution and analysis. In the first category, model creation shares many of the same use cases as other relatively complex software designs. As the languages (such as SystemC) are increasingly based on C++, many of the standard Eclipse plugins can be used. However additional plugins are of some use, for instance specific SystemC syntax highlighting, or model topology visulisation. In the second category, the scope of useful plugins is much wider. In general, these will all be concerned with user interaction with a running (or completed) model. They will encompass plugins to display statistics about the execution of the model (analysis data), and others to elicit input from the user to control a model's execution.

Overall, a typical use case would be for an Electronic System Engineer to initially import a number of pre-existing models into their environment. They may use some VPP topology visualization plugins to help understand the connectivity of the model they are trying to build. They may then go on to build a few "component models" themselves, using many already existing Eclipse plugins, and some VPP additions. Having debugged the model, again with a combination of plugins, they would then go on to execute the model, controlling its execution through other VPP plugins. Finally, they will need to extract data from the model (the reason for constructing the model in the first place!). This data will be provided to the user through VPP plugins.

Project Principles

Among the key principles on which this project has been initiated, and will be run, are the following:

Leverage Eclipse Ecosystem - A major goal of this project is to apply the application development strengths of Eclipse to the System Level Design Domain (especially as, in the end, a System Level model is nothing more than a relatively constrained, but none the less complex, application). The project will work closely with other Eclipse project areas whenever possible to leverage the capabilities being developed in those areas.

Vendor Neutral - We aim to encourage Eclipse participation and drive Eclipse market acceptance by providing vendor-neutral capabilities and to encourage participation for complementary capabilities through additional projects.

Open, Standards-based Development - Where market adopted standards exist that meet the design goals, our aim is to leverage and adhere to them. Where market adopted standards do not exist, we will develop and publish any new capabilities in the Eclipse open forum.

Incremental Delivery - In order to meet the pent-up demand for a standardized framework for device software development tools, we aim to deliver functionality to the market as rapidly as possible via an incremental delivery model.

Project Scope

Within the development of Device Software, three phases are identified:

• Hardware Bring-up
• Platform Software Development
• Application Software Development

System Level Design includes all of these, but with respect to models. In addition, the Bring-up phase will apply to models of functional components that may be destined for implementation in a combination of hardware and software and there is one more phase: Hardware/Software partitioning, or model abstraction level decisions In this phase, designers decide at what level they need to (or can) model items in their system. At high levels of abstraction it may not be clear if this item will be implemented in hardware or in software. At lower levels details about the implementation become important. The VPP will use or adapt other projects within DSDP to address the other three design phases as they relate to system level design and will add specific exemplary tools aimed at assisting in the hardware/software partitioning task.

Having designed a model, and chosen a level of abstraction suitable for the use cases to which the model is to be applied, the wider range of Eclipse tools and plug-ins will be required including:

• Model Debug
• System Visualization
• Model specific Analysis
• Transaction level analysis (communication between Virtual components)
• Model execution profiling
• User interactions
• Configuration
• Control (User based control, and script based control)

SystemC (and related languages)

Specifically within the domain of System Level Design, SystemC is used as the modeling language of choice. It is based on C++ and can therefore be used to build software and hardware components. As it is a language in its own right, there are language related extensions to Eclipse that fall within this project.

Initial technologies

• SystemC Syntax highlighting
• SystemC topology viewer (to view the hardware components of a system, typically fed by a SystemC parser)
• Display of analysis information published by SystemC models
• Profiling of SystemC simulations (this requires hooks into the SystemC kernel to provide simulation activity in order to improve simulation performance)

For each of these, work in disparate organizations is already taking place, GreenSocs (see below) aims to pull this work together in one central place and to feed that into VPP.

Organization

There is already a project similar in conception to Eclipse called the GreenSocs Eclipse Project, which is focused solely on System Level Design infrastructure and built for the most part around SystemC, within which Eclipse should form a part. Hence the logical point of interaction between Eclipse and GreenSocs is the VPPy project, which GreenSocs will run within Eclipse. GreenSocs will aim to collect funding and supply engineering to continue the development effort, but also to coordinate activities such as those within universities worldwide that are engaged in developing Eclipse extensions for ESL. Greensocs is already committed to offer initial contributions. This will occur soon after the project is created. GreenSocs will encourage and coordinate contributions for other organizations, expected from a number of industrial and academic institutions.

Interested Parties

Industrial Organizations

Xilinx Research investigates ESL technologies for FPGA designers and strongly believes that a robust open-source solution for model development, debug and analysis is needed. This project's goal (to build open-source modeling extensions to Eclipse) is both timely and well focused on the set of core problems that an Eclipse open source solution could address. In terms of direct support, Xilinx Research will continue to offer technical guidance to the project and may donate code to accelerate the development of Eclipse plug-in modules.

University Organizations

FZI (a research organization of German Universities), Unicamp (a similar organization based in Brazil), and EIS (a research lab at TU Braunschweig, Germany) have contributed to the current efforts GreenSocs has made in building some of the components required by VPP.

Contact Person

Mark Burton (mark.burton@greensocs.com)

Roadmap

The intention is to provide basic plugins to support SystemC modeling and debug straight away. These will not be of sufficient quality to warrant a 1.0 release, but will be worked on to achieve that goal. Other parallel activities will focus on model to user interactions. This work is expected to be industrially funded, with GreenSocs providing the resource.