File system access from reconfigurable FPGA hardware processes in BORPH

This paper presents the design and implementation of BORPHpsilas kernel file system layer that provides FPGA processes direct access to the general file system. Using a semantics resembling that of conventional UNIX file I/Os, an FPGA accesses the file system through a special hardware system call interface. By extending the semantics of a UNIX pipe, a single file system access mechanism is used for both regular file I/O, as well as for hardware/software and hardware/hardware data streaming. An FPGA design may switch between different communication modes dynamically during run time by means of file redirection. Design trade-offs among system manageability, user usability and application performance are explored. An example of constructing a video processing system during run time using commodity software and FPGA applications connected by pipes is used to demonstrate the feasibility and potential of such FPGA-centric file system access capability.