WIP: Initial work on constraint file support. Not yet usable.

azonenberg · azonenberg · commit 3c0011cf8913 · 2017-02-15T10:05:49.000-08:00
diff --git a/doc/gp4-hdl.tex b/doc/gp4-hdl.tex
@@ -261,18 +261,39 @@ \subsection{\namestyle{Yosys} Verilog Inference Limitations for GreenPAK}
 \pagebreak
 \section{\namestyle{gp4par} HDL Constraints}
 
-There is only one supported constraint entry format at this time, Verilog attributes. There is currently no support for
-adding constraints to netlist entities via external constraint files or command line arguments. The general format of a
-constraint with name \tokenstyle{FOO} and value 42 applied to the register \wirestyle{foobar} is shown in Figure
-\ref{constraint}.
+Constraints may be entered by Verilog attributes or an external Physical Constraints File (.pcf) file. In the event of
+a conflict, the PCF takes precedence over constraints in the Verilog. If two constraints in the same PCF file conflict,
+the later constraint takes precedence.
+
+\subsection{Verilog attributes}
+
+The general format of a constraint with name \tokenstyle{FOO} and value 42 applied to the register \wirestyle{foobar}
+is shown in Figure \ref{constraint-verilog}.
 
 \begin{figure}[h]
 \begin{lstlisting}
 (* FOO=42 *)
 reg[3:0] foobar = 0;
 \end{lstlisting}
 \caption{Example Verilog attribute constraint}
-\label{constraint}
+\label{constraint-verilog}
+\end{figure}
+
+\subsection{PCF constraints}
+
+\namestyle{gp4par} PCF files used a syntax similar to that of the industry standard Synopsys Design Constraints (SDC).
+Only constraints are supported; arbitrary TCL cannot be used.
+
+The general format of a constraint with name \tokenstyle{FOO} and value 42 applied to the register \wirestyle{foobar}
+is shown in Figure \ref{constraint-pcf}.
+
+\begin{figure}[h]
+\begin{lstlisting}
+# set some random attribute
+set_foo foobar 42
+\end{lstlisting}
+\caption{Example PCF constraint}
+\label{constraint-pcf}
 \end{figure}
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/src/gp4par/main.cpp b/src/gp4par/main.cpp
@@ -328,7 +328,9 @@ int main(int argc, char* argv[])
 void ShowUsage()
 {
 	printf(//                                                                               v 80th column
-		"Usage: gp4par -p part -o bitstream.txt netlist.json\n"
+		"Usage: gp4par [options] -p part -o bitstream.txt netlist.json\n"
+		"    -c <file>\n"
+		"        Reads placement constraints from <file>\n"
 		"    --debug\n"
 		"        Prints lots of internal debugging information.\n"
 		"    --disable-charge-pump\n"
diff --git a/src/greenpak4/Greenpak4Netlist.cpp b/src/greenpak4/Greenpak4Netlist.cpp
@@ -28,7 +28,7 @@ Greenpak4NetlistEntity::~Greenpak4NetlistEntity()
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // Construction / destruction
 
-Greenpak4Netlist::Greenpak4Netlist(std::string fname)
+Greenpak4Netlist::Greenpak4Netlist(string fname, string constraint_file)
 	: m_topModule(NULL)
 	, m_parseOK(true)
 {
@@ -94,6 +94,19 @@ Greenpak4Netlist::Greenpak4Netlist(std::string fname)
 	json_object_put(object);
 	json_tokener_free(tok);
 	delete[] json_string;
+
+	//Read the constraint file (if we have one)
+	if(constraint_file == "")
+		return;
+	fp = fopen(constraint_file.c_str(), "r");
+	if(fp == NULL)
+	{
+		LogError("Failed to open constraint file %s\n", fname.c_str());
+		m_parseOK = false;
+		return;
+	}
+	LoadConstraints(fp);
+	fclose(fp);
 }
 
 Greenpak4Netlist::~Greenpak4Netlist()
@@ -107,6 +120,14 @@ Greenpak4Netlist::~Greenpak4Netlist()
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // Parsing stuff
 
+/**
+	@brief Parsing for a PCF file
+ */
+void Greenpak4Netlist::LoadConstraints(FILE* fp)
+{
+
+}
+
 /**
 	@brief Top-level parsing routine
 
diff --git a/src/greenpak4/Greenpak4Netlist.h b/src/greenpak4/Greenpak4Netlist.h
@@ -33,7 +33,7 @@
 class Greenpak4Netlist
 {
 public:
-	Greenpak4Netlist(std::string fname);
+	Greenpak4Netlist(std::string fname, std::string constraint_file = "");
 	virtual ~Greenpak4Netlist();
 
 	Greenpak4NetlistModule* GetTopModule()
@@ -64,6 +64,7 @@ class Greenpak4Netlist
 	//Init helpers
 	void Load(json_object* object);
 	void LoadModules(json_object* object);
+	void LoadConstraints(FILE* fp);
 
 	std::string m_creator;
 
diff --git a/tests/greenpak4/CMakeLists.txt b/tests/greenpak4/CMakeLists.txt
@@ -69,7 +69,7 @@ function(add_greenpak4_bitstream name part)
 		OUTPUT  "${CMAKE_CURRENT_BINARY_DIR}/${name}.txt"
 		COMMAND gp4par "--stdout-only"
 					   --usercode 41
-					   --quiet
+					   # --quiet
 					   --part ${part}
 					   --output  "${CMAKE_CURRENT_BINARY_DIR}/${name}.txt"
 					   --logfile "${CMAKE_CURRENT_BINARY_DIR}/${name}-par.log"
diff --git a/tests/greenpak4/slg46620v/Location.v b/tests/greenpak4/slg46620v/Location.v
@@ -18,7 +18,7 @@
 
 `default_nettype none
 
-module Location(a, b, c, d, e);
+module Location(a, b, c, d, e, f);
 
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// I/O declarations
@@ -41,6 +41,9 @@ module Location(a, b, c, d, e);
 	(* LOC = "P16" *)
 	input wire e;
 
+	//LOC'd by constraint file
+	output wire f;
+
 	////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 	// Clock/reset stuff
 
