Sky130 Plugin (#614)

doc/Technology/index.rst

@@ -5,7 +5,7 @@ Technology Setup and Use
 
 These guides will walk you through how to set up a technology to be used in Hammer.
 
-You may use the included `free ASAP7 PDK example <https://github.com/ucb-bar/hammer/tree/master/src/hammer-vlsi/technology/asap7>`__ as a reference when building your own technology plugin.
+You may use the included `free ASAP7 PDK <https://github.com/ucb-bar/hammer/tree/master/src/hammer-vlsi/technology/asap7>`__ or the `open-source Sky130 PDK <https://github.com/ucb-bar/hammer/tree/master/src/hammer-vlsi/technology/sky130>`__ plugins as reference when building your own technology plugin.
 
 .. toctree::
    :maxdepth: 2

src/hammer-tech/hammer_tech.py

@@ -361,6 +361,20 @@ def cache_dir(self, value: str) -> None:
         self._cachedir = value  # type: str
         # Ensure the cache_dir exists.
         os.makedirs(value, mode=0o700, exist_ok=True)
+
+    # @classmethod
+    def expand_tech_cache_path(self, path) -> str:
+        """ Replace occurrences of the cache directory's basename with
+            the full path to the cache dir."""
+        cache_dir_basename = os.path.basename(self.cache_dir)
+        return path.replace(cache_dir_basename, self.cache_dir)
+
+    # @classmethod
+    def ensure_dirs_exist(self, path) -> None:
+        dir_name = os.path.dirname(path)
+        if not os.path.exists(dir_name):
+            self.logger.info('Creating directory: {}'.format(dir_name))
+            os.makedirs(dir_name)
 
     # hammer-vlsi properties.
     # TODO: deduplicate/put these into an interface to share with HammerTool?

src/hammer-vlsi/technology/sky130/README.md

@@ -0,0 +1,155 @@
+Sky130 Technology Library
+=========================
+HAMMER now supports the Skywater 130nm Technology process. The [SkyWater Open Source PDK](https://skywater-pdk.readthedocs.io/) is a collaboration between Google and SkyWater Technology Foundry to provide a fully open source Process Design Kit (PDK) and related resources, which can be used to create manufacturable designs at SkyWater’s facility.
+The Skywater 130nm PDK files are located in a repo called [skywater-pdk](https://github.com/google/skywater-pdk/) A tool called [Open-PDKs (open_pdks)](https://github.com/RTimothyEdwards/open_pdks/) was developed to generate all the files typically found in a PDK.
+Open-PDKs uses the contents in `skywater-pdk`, and outputs files to a directory called `sky130A`.
+
+[OpenLANE](https://github.com/efabless/openlane/) is an open-source RTL to GDSII VLSI flow that supports Sky130.
+
+
+Before setting up the Sky130 PDK, we recommend familiarizing yourself with the process's documentation [summarized below](#Resources).
+
+PDK Structure
+-------------
+
+OpenLANE expects a certain file structure for the Sky130 PDK. 
+We recommend adhering to this file structure for Hammer as well.
+All the files reside in a root folder (named something like `skywater` or `sky130`).
+The environment variable `$PDK_ROOT` should be set to this folder's path:
+
+    export PDK_ROOT=<path-to-skywater-directory>
+
+`$PDK_ROOT` contains the following:
+
+* `skywater-pdk`
+
+  * Original PDK source files
+
+* `open_pdks`
+
+  * install of Open-PDKs tool
+
+* `share/pdk/sky130A`
+
+  * output files from Open-PDKs compilation process
+
+NDA Files
+---------
+Using commercial VLSI tools with this process requires files that are currently under NDA. 
+If you have access to these, you will be able to use the Hammer VLSI flow out-of-the-box with the Sky130 process.
+Some of these NDA files, such as the Calibre DRC/LVS decks, rely on the environment variable `$PDK_HOME` containing the path to the version of the NDA files you are using.
+You may set it in the Hammer plugin, or as follows:
+
+    export PDK_HOME=<path-to-skywater-src-nda>/s8/<version#>
+
+Prerequisites for PDK Setup
+---------------------------
+
+* [Magic](http://opencircuitdesign.com/magic/)
+
+  * required for `open_pdks` file generation
+  * tricky to install, closely follow the directions on the `Install` page of the website
+
+    * as the directions indicate, you will likely need to manually specify the location of the Tcl/Tk package installation using `--with-tcl` and `--with-tk`
+
+ If using conda, these installs alone caused the Magic install to work:
+
+    conda install -c intel tcl 
+    conda install -c anaconda tk 
+    conda install -c anaconda libglu
+
+OpenRAM SRAMs
+-------------
+TODO: add overview here
+
+    git clone https://github.com/efabless/sky130_sram_macros.git
+
+
+PDK Setup
+---------
+In `$PDK_ROOT`, clone the skywater-pdk repo and generate the liberty files for each library:
+
+    git clone https://github.com/google/skywater-pdk.git
+    cd skywater-pdk
+    # Expect a large download! ~7GB at time of writing.
+    git submodule init libraries/*/latest
+    git submodule update
+    # Regenerate liberty files
+    make timing
+
+Again in `$PDK_ROOT`, clone the open_pdks repo and run the install process to generate the `sky130A` directory:
+
+    git clone https://github.com/RTimothyEdwards/open_pdks.git
+    cd open_pdks
+    ./configure \
+    --enable-sky130-pdk=$PDK_ROOT/skywater-pdk/libraries \
+    --prefix=$PDK_ROOT \
+    --enable-sram-sky130=$PDK_ROOT/sky130_sram_macros # if using SRAMs
+    make
+    make install
+
+This generates all the Sky130 PDK files and installs them to `$PDK_ROOT/share/pdk/sky130A`
+
+Known DRC Issues
+----------------
+The HAMMER flow generates DRC-clean digital logic when run with the Calibre DRC deck and SRAMs excluded. 
+
+TODO: summarize issues with SRAMs and open-source Magic DRC checks.
+
+## Resources
+The good thing about this process being open-source is that most questions about the process are answerable through a google search. 
+The tradeoff is that the documentation is a bit of a mess, and is currently scattered over a few pages and Github repos. 
+We try to summarize these below.
+
+Git repos:
+
+* [SkyWater Open Source PDK](https://github.com/google/skywater-pdk/)
+
+  * Git repo of the main Skywater 130nm files
+
+* [Open-PDKs](https://github.com/RTimothyEdwards/open_pdks/)
+
+  * Git repo of Open-PDKs tool that compiles the Sky130 PDK
+
+* [Git repos on foss-eda-tools](https://foss-eda-tools.googlesource.com/)
+
+  * Additional useful repos, such as Berkeley Analog Generator (BAG) setup
+
+Documentation:
+
+* [SkyWater SKY130 PDK's documentation](https://skywater-pdk.readthedocs.io)
+
+  * Main documentation site for the PDK
+
+* [Join the SkyWater PDK Slack Channel](https://join.skywater.tools/)
+
+  * By far the best way to have questions about the process answered, with 80+ channels for different topics
+
+* [Skywater130 Standard Cell and Primitives Overview](http://diychip.org/sky130/)
+
+  * Additional useful documentation for the PDK
+
+* [FOSSi Foundation YouTube Channel](https://www.youtube.com/c/FOSSiFoundation/)
+
+  * Contains informational videos on the Sky130 process, OpenLANE flow, and Efabless Shuttle program
+
+SRAMs:
+
+* [OpenRAM](https://github.com/VLSIDA/OpenRAM/)
+
+  * Open-source static random access memory (SRAM) compiler
+
+* [OpenRAM pre-compiled macros](https://github.com/efabless/sky130_sram_macros/)
+
+  * Precompiled sizes are 1kbytes, 2kbytes and 4kbytes
+
+OpenLANE flow:
+
+* [OpenLANE](https://github.com/efabless/openlane/)
+
+  * Open-source RTL to GDSII flow
+
+* [Magic](http://opencircuitdesign.com/magic/)
+
+  * Open-source VLSI layout tool that handles DRC checks in OpenLANE
+