Weasel: A platform-independent streaming-optimized SATA controller

Abstract

Field-Programmable Gate Arrays, which are widely used as prototyping platforms, are intruding the domain of custom-specific high-performance hardware accelerators, which operate highly efficiently by exploiting bit- and word-level parallelism. One opportunity to feed these FPGA accelerators with Gbytes of data is the direct attachment of mass-storage devices through a Serial-ATA link. State-of-the-art SATA controllers are designed and optimized for microprocessor-based systems with a random memory access pattern. Our approach, named Weasel, introduces a modularized, platform-independent and streaming-optimized SATA controller, which supports link speeds up to 6 Gbit/s. We demonstrate how to customize the given ATA standard and how to design a generic interface for different vendor-specific multi-gigabit transceivers. Implementations of the platform-independent interface for the Xilinx Virtex-5 and the Altera StratixII GX devices prove our concept. Finally, our measurements using hard-disk and solid-state drives prove a sustained throughput of 540 Mbytes/s over a SATA 6 Gbit/s link achievable. This is close to the theoretical maximum, which is constrained by the attached devices as by the speed of their flash memory.