Merge pull request #97 from unixb0y/master

Added database development process to FAQ

docs/db_dev_process/overview.rst

@@ -0,0 +1,35 @@
+Overview
+=========
+
+SymbiFlow/symbiflow-arch-defs
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+This is where we describe the logical components in a device to VPR.
+
+* VtR stands for `Verilog to Routing <https://verilogtorouting.org/>`_,
+* VPR stands for VtR Place and Route.
+* VtR also has its own synthesis tool called ODIN-II, but we are using `Yosys <https://github.com/YosysHQ/yosys>`_ instead of that.
+  
+
+SymbiFlow/prjxray/fuzzers/
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Fuzzers are things that generate a design, feed it to Vivado, and look at the resulting bitstream to make some conclusion.
+This is how the contents of the database are generated.
+
+The general idea behind fuzzers is to pick some element in the device (say a block RAM or IOB) to target.
+If you picked the IOB (no one is working on that yet), you'd write a design that is implemented in a specific IOB.
+Then you'd create a program that creates variations of the design (called specimens) that vary the design parameters, for example, changing the configuration of a single pin.
+
+A lot of this program is TCL that runs inside Vivado to change the design parameters, because it is a bit faster to load in one Verilog model and use TCL to replicate it with varying inputs instead of having different models and loading them individually.
+
+By looking at all the resulting specimens, you can correlate which bits in which frame correspond to a particular choice in the design.
+
+Looking at the implemented design in Vivado with "Show Routing Resources" turned on is quite helpful in understanding what all choices exist.
+
+SymbiFlow/prjxray/tools/
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Here, you can find various programs to work with bitstreams, mainly to assist building fuzzers.
+
+SymbiFlow/prjxray/minitests/roi_harness
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+Shows how to use a bunch of tools together to patch an existing bitstream with hand-crafted FASM (FPGA assembler).
+

docs/index.rst

@@ -21,3 +21,9 @@ to develop a free and open Verilog to bitstream toolchain for these devices.
    architecture/configuration
    architecture/bitstream_format
    architecture/glossary
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Database Development Process
+   
+   db_dev_process/overview