add shell.nix & set proper openlane tags for other pdks and scls

Makefile

@@ -60,7 +60,7 @@ endif
 ifeq ($(PDK),sky130B)
 	SKYWATER_COMMIT=f70d8ca46961ff92719d8870a18a076370b85f6c
 	export OPEN_PDKS_COMMIT?=78b7bc32ddb4b6f14f76883c2e2dc5b5de9d1cbc
-	export OPENLANE_TAG?=2023.07.19
+	export OPENLANE_TAG?=2.0.0-b4
 	MPW_TAG ?= mpw-9d
 
 ifeq ($(CARAVEL_LITE),1)
@@ -81,9 +81,8 @@ ifeq ($(PDK),gf180mcuC)
 	CARAVEL_NAME := caravel
 	CARAVEL_REPO := https://github.com/efabless/caravel-gf180mcu
 	CARAVEL_TAG := $(MPW_TAG)
-	#OPENLANE_TAG=ddfeab57e3e8769ea3d40dda12be0460e09bb6d9
 	export OPEN_PDKS_COMMIT?=e6f9c8876da77220403014b116761b0b2d79aab4
-	export OPENLANE_TAG?=2023.02.23
+	export OPENLANE_TAG?=2.0.0-b4
 
 endif
 

openlane/shell.nix

@@ -0,0 +1,25 @@
+# Copyright 2023 Efabless Corporation
+#
+# 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.
+{
+    pkgs ? import (fetchTarball "https://github.com/NixOS/nixpkgs/archive/0218941ea68b4c625533bead7bbb94ccce52dceb.tar.gz") {},
+    openlane-version ? "8b47c810ae47835079e09bbec8ff945c4b90b14a",
+    openlane-sha256 ? "sha256-I6vZhkqH+7InaQrmxWYJSuK0PKrMEA/UFAzfqFseR3A="
+}:
+
+let openlane-src = pkgs.fetchFromGitHub {
+    owner = "efabless";
+    repo = "openlane2";
+    rev = openlane-version;
+    sha256 = openlane-sha256;
+}; in import "${openlane-src}/shell.nix" {}