[doc] updates to topgen
diff --git a/doc/rm/_index.md b/doc/rm/_index.md
index 0f89e6b..0082610 100644
--- a/doc/rm/_index.md
+++ b/doc/rm/_index.md
@@ -2,6 +2,7 @@
* [Comportability Definition and Specification]({{< relref "comportability_specification" >}})
* Tool Guides
+ * [Topgen Tool]({{< relref "topgen_tool" >}}): Describes `topgen.py` and its Hjson format source. Used to generate rtl and validation files for top specific modules such as PLIC, Pinmux and crossbar.
* [Register Tool]({{< relref "register_tool" >}}): Describes `regtool.py` and its Hjson format source. Used to generate documentation, rtl, header files and validation files for IP Registers and toplevel.
* [Crossbar Tool]({{< relref "crossbar_tool" >}}): Describes `tlgen.py` and its Hjson format source. Used to generate self-documentation, rtl files of the crossbars at the toplevel.
* [Vendor-In Tool]({{< relref "vendor_hw_tool" >}}): Describes `vendor_hw.py` and its Hjson control file. Used to pull a local copy of code maintained in other upstream repositories and apply local patch sets.
diff --git a/doc/rm/topgen_tool.md b/doc/rm/topgen_tool.md
index c3c8d4e..97d4ae2 100644
--- a/doc/rm/topgen_tool.md
+++ b/doc/rm/topgen_tool.md
@@ -54,6 +54,8 @@
Likewise, the top does not need to know the details of why an interrupt is generated, just how many there are.
The user supplied `top_*.hjson` thus acts like a integration specification while the remaining details are filled in through lower level inputs.
+In addition to design collateral, the tool also generates all the top level RAL (Register Abstraction Layer) models necessary for verification.
+
### Validation, Merge and Output
As stated previously, each of the gathered component Hjson files is validated for correctness.
