docs: added `route_diag` documentation
Signed-off-by: Alessandro Comodi <acomodi@antmicro.com>
diff --git a/doc/src/utils/index.rst b/doc/src/utils/index.rst
index fd804f8..af1d8c7 100644
--- a/doc/src/utils/index.rst
+++ b/doc/src/utils/index.rst
@@ -7,3 +7,4 @@
:maxdepth: 2
fasm
+ route_diag
diff --git a/doc/src/utils/route_diag.rst b/doc/src/utils/route_diag.rst
new file mode 100644
index 0000000..aa6fb76
--- /dev/null
+++ b/doc/src/utils/route_diag.rst
@@ -0,0 +1,37 @@
+.. _route_diag:
+
+Router Diagnosis Tool
+=====================
+
+The Router Diagnosis tool (``route_diag``) is an utility that helps developers understand the issues related to the routing phase of VPR.
+Instead of running the whole routing step, ``route_diag`` performs one step of routing, aimed at analyzing specific connections between a SINK/SOURCE nodes pair.
+Moreover, it is able also to profile all the possible paths of a given SOURCE node.
+
+To correctly run the utility tool, the user needs to compile VTR with the ``VTR_ENABLE_DEBUG_LOGGING`` set to ON and found in the CMakeLists.txt_ configuration file.
+
+.. _CMakeLists.txt: https://github.com/verilog-to-routing/vtr-verilog-to-routing/blob/01ff7e174d9d53753a2f981d7be0052b612b5874/CMakeLists.txt#L36
+
+The tool is compiled with all the other targets when running the full build of VtR. It is also possible, though, to build the ``route_diag`` utility standalone, by running the following command:
+
+.. code-block:: bash
+
+ make route_diag
+
+To use the Route Diagnosis tool, the users has different parameters at disposal:
+
+.. option:: --sink_rr_node <int>
+
+ Specifies the SINK RR NODE part of the pair that needs to be analyzed
+
+.. option:: --source_rr_node <int>
+
+ Specifies the SOURCE RR NODE part of the pair that needs to be analyzed
+
+.. option:: --router_debug_sink_rr <int>
+
+ Controls when router debugging is enabled for the specified sink RR.
+
+ * For values >= 0, the value is taken as the sink RR Node ID for which to enable router debug output.
+ * For values < 0, sink-based router debug output is disabled.
+
+The Router Diagnosis tool must be provided at least with the RR GRAPH and the architecture description file to correctly function.
