基于嵌入式Linux的可自重构片上系统(4)

VI. Challenges and future work

So far we have deliberately avoided discussion on the mechanics of actually generating partial bitstreams, design modularisation, dynamic bitstream parameterisation and so on.

The practical difficulties facing researchers and practitioners in this regard are substantial. At the present time, synthesis and implementation tool support for these efforts is limited.

To implement and test our examples above, we used partial bit streams laboriously hand-created using the Xilinx FPGA Editor tool. This is partly because the modular and partial reconfiguration implementation flows are not supported for Microblaze and EDK (Embedded Development Kit) projects.

We have recently successfully “modularised” the Microblaze flow, and are in the process of automating this, so that reconfigurable modules

基于嵌入式Linux的可自重构片上系统

may be easily specified, and interfaced to Microblaze processor systems. This will greatly simplify the process of creating pre-defined modular bitstreams.

The issues mentioned previously in the discussion remain as important and fruitful avenues for further investigation.

remote network-based bitstream acquisition and reconfiguration could be implemented in as little as a single line of shell script code. Readback and configuration verification was shown to easily integrate within this framework.

The idea of using the same driver interface and architecture to control the configuration of arrays of FPGAs was proposed as a natural and simple extension of the approach.

One of the major challenges in the design and implementation of dynamic and self reconfiguring systems is to coerce the logic implementation tools to produce the appropriate partial bit streams, and also the dynamic modification of those bit streams to allow dynamic logic placement and other capabilities. There are a number of research and commercial groups working on these problems, and success in these areas could be readily translated into our platform and tool approach.

VII. Conclusions

We have implemented and described a methodology and set of tools for implementing dynamically and self-reconfigurable systems, using embedded Linux as a powerful and flexible platform.

As the logic density and speed of FPGAs continues to increase, the relative cost of placing soft (or hard) processor logic in these devices diminishes. Similarly, the relative cost of using a complete embedded operating system such as uClinux also decreases. By adopting a platform based approach, designers and researchers can gain tremendous leverage.

By adopting the standard Linux device driver approach and philosophy, the ICAP reconfiguration mechanism becomes available to user programs, as well as higher level shell scripts. Examples were presented to show how complex behaviours such as [1]

Acknowledgements

The authors would like to thank the members of the Xilinx EDK team and Xilinx Labs. This research is partly supported by the Australian Government via the Australian Research Council.

References

B. Blodget, S. McMillan, and P. Lysaght, "A lightweight approach for embedded reconfiguration of FPGAs," in Proc. IEEE Design Automation and Test in Europe, pp. 339-340, Munich, Germany, 2003.

N. W. Bergmann, J. A. Williams, and P. J. Waldeck, "A Flexible Platform for Real-Time Reconfigurable Systems on Chip," in Proc. International Conference on Engineering of Reconfigurable Systems and Algorithms, pp. 300-303, Las Vegas, USA, 2003. Xilinx, "Microblaze Processor Reference Guide," Xilinx, Inc, 2003, pp. 136.

A. Rubini and J. Corbet, Linux Device Drivers, 2nd ed: O'Reilly and Associates, 2001.

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G. Wigley and D. Kearney, "The Development of an Operating System for Reconfigurable Computing," in Proc. IEEE Symposium on FCCM, 2001.

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[2]

[3] [4] [5] [6]

[7] [8]

[9] [10]

基于嵌入式Linux的可自重构片上系统