rework motivation for FPGA-Verilog and FPGA-Bitstream in documentation

docs/source/motivation.rst

@@ -20,19 +20,16 @@ The technical details can be found in our ICCD’15 paper :cite:`XTang_ICCD_2015
 FPGA-Verilog
 ------------
 
-On a second note, it is becoming more and more necessary to have fast access to the Verilog code of the structures and architectures researchers want to study. We think that some issues cannot be studies through VPR only and a complete overview is possible through a more extensive workflow. One of the prerequisites for this is the generation of the Verilog which enables Place & Route and Signoff analysis. While VPR allows the researcher to have access to fast results if the characteristics of the system are well known by the user, it is quite limited otherwise. In the same way, it is quite hard to study the same architecture across multiple technology nodes without substantial knowledge of it. 
-
-This motivates us to generate the Verilog code of the architecture to enable a second level of research concerning the architectures to be explored. This Verilog code encompasses the whole design and is divided into multiple sub-directories for targetted analysis or a global one. This is left to the choice of the user. 
-
-In this manual, we present FPGA-Verilog. This extension enables the generation of a fully functional Verilog code enabling a deeper understanding of the architectures of the FPGAs. We introduce different options to this module to do the verification of the system. This will be presented in more depth in the FPGA-Bitstream section.
+Driven by the strong need in data processing applications, Field Programmable Gate Arrays (FPGAs) are playing an ever-increasing role as programmable accelerators in modern
+computing systems. To fully unlock processing capabilities for domain-specific applications, FPGA architectures have to be tailored for seamless cooperation with other computing resources. However, prototyping and bringing to production a customized FPGA is a costly and complex endeavor even for industrial vendors. OpenFPGA, an opensource framework, aims to rapid prototype of customizable FPGA architectures through a semi-custom design approach. We propose an XML-to-Prototype design flow, where the Verilog netlists of a full FPGA fabric can be autogenerated using an extension of the XML language from the VTR framework and then fed into a back-end flow to generate production-ready layouts. 
 
 The technical details can be found in our TVLSI'19 paper :cite:`XTang_TVLSI_2019` and FPL'19 paper :cite:`XTang_FPL_2019`.
 
 FPGA-Bitstream
 --------------
 
-To have the right functionality on top of the FPGA generated, it is necessary to have a Bitstream generation which programs the FPGA. For this reason, we generate a Bitstream and some testbenches in parallel which allow the user to do some functional verification of the system to make sure that the functionality is respected. This includes three different testbenches. First, the FPGA is configured then the clock runs with random patterns are generated to test the functionality. Secondly, the FPGA can be configured in parallel to the testbench itself to do a comparison of the signals and check the validity. Finally, the configuration can be skipped to directly have access to the functioning of the system and reduce the processing time.
+EDA support is essential for end-users to implement designs on a customized FPGA. OpenFPGA provides a general-purpose bitstream generator FPGA-Bitstream for any architecture that can be described by VPR. As the native CAD tool for any customized FPGA that is produced by FPGA-Verilog, FPGA-Bitstream is ready to use once users finalize the XML-based architecture description file. This eliminates the huge engineering efforts spent on developing bitstream generator for customized FPGAs.
 
-This will be explained in more depth in the FPGA-Bitstream section.
+Using FPGA-Bitstream, users can launch (1) Verilog-to-Bitstream flow. This is the typical implementation flow for end-users; (2) Verilog-to-Verification flow. OpenFPGA can output Verilog testbenches with self-testing features to validate users' implemetations on their customized FPGA fabrics.
 
 The technical details can be found in our TVLSI'19 paper :cite:`XTang_TVLSI_2019` and FPL'19 paper :cite:`XTang_FPL_2019`.