diff --git a/requirements.txt b/requirements.txt
index 2427f9490a3dd5a7ffe0e0a8cf2ad19af0934cdf..6b8e4d02c8ca1dcdbe607aabdccd27cec8056332 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,4 +8,5 @@ pre-commit
 pyverilator
 scipy
 sphinx
+toposort
 wget