A Linux-based support for developing real-time applications on heterogeneous platforms with dynamic FPGA reconfiguration

Heterogeneous computing platforms including both processors and field programmable gate arrays (FPGAs) represent an attractive solution for balancing software flexibility with high performance and energy efficiency of custom hardware modules. Furthermore, the dynamic partial reconfiguration (DPR) capabilities of modern FPGAs allow virtualizing the available area to support several hardware modules in time sharing, hence making them even more attractive. Such a feature is exploited by the FRED framework, recently proposed to support the development of real-time applications upon such platforms. This paper presents an implementation of the FRED framework for the Linux operating system over the Zynq-7000 platform produced by Xilinx. Design solutions for managing hardware accelerators are first discussed. Then, a software architecture for Linux is presented, which comprises (i) support for shared-memory communication with hardware accelerators, (ii) an improved driver to handle the FPGA reconfiguration and (iii) a scheduler for requests of hardware acceleration. The proposed solution allows exploiting the enormous number of software systems available for Linux (such as drivers, libraries, communication stacks, etc.) and the typical programming flexibility of software, while relying on predictable hardware acceleration of heavy computations.