feat: add cocotb (Linux only)

Signed-off-by: Leo Moser <[email protected]>

Author: mole99

Readme.md

@@ -26,6 +26,8 @@ We compile and cache the tools for the following platforms:
     * (+ `klayout-gdsfactory` as a shorthand for an environment with both installed)
 * [Verilator](https://verilator.org)
 * [Icarus Verilog](https://github.com/steveicarus/iverilog)
+* [cocotb](https://www.cocotb.org/)
+    * Linux only.
 * [Xschem](https://xschem.sourceforge.io/stefan/index.html)
 * [Xyce](https://github.com/xyce/xyce)
     * Linux only.

flake.nix

@@ -62,6 +62,7 @@
           self.composePythonOverlay (pkgs': pkgs: pypkgs': pypkgs: let
             callPythonPackage = lib.callPackageWith (pkgs' // pypkgs');
           in {
+            cocotb = callPythonPackage ./nix/cocotb.nix {};
             kfactory = pypkgs.kfactory.overrideAttrs (attrs': attrs: {
               version = "1.9.3";
               src = pypkgs'.fetchPypi {
@@ -157,11 +158,12 @@
               yosys-slang
             ]
             ++ lib.optionals (lib.lists.any (el: el == system) yosys-ghdl.meta.platforms) [yosys-ghdl]);
-          inherit (pkgs) magic magic-vlsi netgen klayout klayout-gdsfactory tclFull tk-x11 verilator xschem ngspice bitwuzla yosys yosys-sby yosys-eqy yosys-lighter yosys-slang;
+          inherit (pkgs) magic magic-vlsi netgen klayout klayout-gdsfactory tclFull tk-x11 iverilog verilator xschem ngspice bitwuzla yosys yosys-sby yosys-eqy yosys-lighter yosys-slang;
           inherit (pkgs.python3.pkgs) gdsfactory gdstk tclint;
         }
         // lib.optionalAttrs self.legacyPackages."${system}".stdenv.hostPlatform.isLinux {
           inherit (pkgs) xyce;
+          inherit (pkgs.python3.pkgs) cocotb;
         }
         // lib.optionalAttrs self.legacyPackages."${system}".stdenv.hostPlatform.isx86_64 {
           inherit (pkgs) yosys-ghdl;

nix/cocotb.nix

@@ -0,0 +1,118 @@
+# Copyright 2025 nix-eda Contributors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# Code adapated from nixpkgs, original license follows
+# ---
+# Copyright (c) 2003-2025 Eelco Dolstra and the Nixpkgs/NixOS contributors
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+{
+  lib,
+  buildPythonPackage,
+  fetchFromGitHub,
+  setuptools,
+  setuptools-scm,
+  cocotb-bus,
+  find-libpython,
+  pytestCheckHook,
+  swig,
+  iverilog,
+  ghdl,
+  stdenv,
+  # Metadata
+  version ? "1.9.2",
+  sha256 ? "sha256-7KCo7g2I1rfm8QDHRm3ZKloHwjDIICnJCF8KhaFdvqY=",
+}:
+let
+  self = buildPythonPackage rec {
+    pname = "cocotb";
+    inherit version;
+    format = "setuptools";
+
+    # pypi source doesn't include tests
+    src = fetchFromGitHub {
+      owner = "cocotb";
+      repo = "cocotb";
+      tag = "v${version}";
+      inherit sha256;
+    };
+
+    nativeBuildInputs = [ setuptools-scm ];
+
+    buildInputs = [ setuptools ];
+    propagatedBuildInputs = [ find-libpython ];
+
+    postPatch = ''
+      patchShebangs bin/*.py
+
+      # POSIX portability (TODO: upstream this)
+      for f in \
+        cocotb/share/makefiles/Makefile.* \
+        cocotb/share/makefiles/simulators/Makefile.*
+      do
+        substituteInPlace $f --replace 'shell which' 'shell command -v'
+      done
+
+      # remove circular dependency cocotb-bus from setup.py
+      substituteInPlace setup.py --replace "'cocotb-bus<1.0'" ""
+    '';
+
+    disabledTests = [
+      # https://github.com/cocotb/cocotb/commit/425e1edb8e7133f4a891f2f87552aa2748cd8d2c#diff-4df986cbc2b1a3f22172caea94f959d8fcb4a128105979e6e99c68139469960cL33
+      "test_cocotb"
+      "test_cocotb_parallel"
+    ];
+
+    nativeCheckInputs = [
+      cocotb-bus
+      pytestCheckHook
+      swig
+      iverilog
+      ghdl
+    ];
+
+    preCheck = ''
+      export PATH=$out/bin:$PATH
+      mv cocotb cocotb.hidden
+    '';
+
+    pythonImportsCheck = [ "cocotb" ];
+
+    meta = {
+      changelog = "https://github.com/cocotb/cocotb/releases/tag/v${version}";
+      description = "Coroutine based cosimulation library for writing VHDL and Verilog testbenches in Python";
+      mainProgram = "cocotb-config";
+      homepage = "https://github.com/cocotb/cocotb";
+      license = lib.licenses.bsd3;
+      broken = stdenv.hostPlatform.isDarwin;
+    };
+  };
+in
+self

nix/iverilog.nix

@@ -1,4 +1,4 @@
-# Copyright 2025 Ciel Contributors
+# Copyright 2025 nix-eda Contributors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

nix/verilator.nix

@@ -1,4 +1,4 @@
-# Copyright 2025 Ciel Contributors
+# Copyright 2025 nix-eda Contributors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.