6.2. Hammer End-to-End Integration Tests

The hammer/e2e folder contains an end-to-end (RTL -> GDS) smoketest flow using Hammer, either the Cadence or OpenROAD toolchain, and the ASAP7 or Skywater 130 PDKs.

6.2.1. Setup

First, follow the Hammer Power User Setup to clone Hammer and install/activate the virtual environment.

6.2.2. Overview

6.2.2.1. Flow Selection

The following variables in the Makefile select the target flow to run:

  • design - RTL name

    • {pass, gcd, sram_wrapper_sky130}

  • pdk - PDK name

    • {sky130, asap7}

  • tools - CAD tool flow

    • {cm (commercial), or (OpenROAD)}

  • env - compute environment

    • {bwrc (BWRC), a (Millenium), inst (instructional machines)}

The outputs of the flow by default reside in OBJ_DIR=build-<pdk>-<tools>/<design>/

6.2.2.2. Configs

The Hammer configuration files consist of environment (ENV_YML) and project (PROJ_YMLS) configurations. The environment configs take precedence over ALL project configs. The order of precedence for the project configs reads from right to left (i.e. each file overrides all files to its left). All configuration files are summarized below.

#         lowest precedence -------------------------------------------> highest precendence
CONFS ?= $(PDK_CONF) $(TOOLS_CONF) $(DESIGN_CONF) $(DESIGN_PDK_CONF) $(SIM_CONF) $(POWER_CONF)

  • ENV_YML- Environment configs that specify CAD tool license servers and paths are in configs-env. This will take precedence over any other config file

  • PDK_CONF - PDK configs shared across all runs with this PDK are in configs-pdk

  • TOOLS_CONF - Tool configs to select which CAD tool flow to use are in configs-tools

  • Design-specific configs are located in configs-design/<design>, and are summarized below:

    • DESIGN_CONF - the common design config (design input files, anything else design-specific)

    • DESIGN_PDK_CONF - PDK-specific configs for this particular design (clock, placement, pin constraints)

    • SIM_CONF - Simulation configs for post-RTL, Synthesis, or PnR simulation

    • POWER_CONF - Power simulation configs for post-RTL, Synthesis, or PnR simulation (NOTE: The Makefile expects the power config filename for each simulation level + PDK to be in the format power-{rtl,syn,par}-<pdk>.yml, while the joules.yml and voltus.yml files serve as templates for the Cadence Joules/Voltus power tools)

6.2.3. Run the Flow

First, use Hammer to construct a Makefile fragment with targets for all parts of the RTL -> GDS flow. Specify the appropriate env/tools/pdk/design variables to select which configs will be used.

make build
# same as: `make env=bwrc tools=cm pdk=sky130 design=pass build`

Hammer will generate a Makefile fragment in OBJ_DIR/hammer.d.

Then run the rest of the flow, making sure to set the env/tools/pdk/design variables as needed:

make sim-rtl
make power-rtl

make syn
make sim-syn
make power-syn

make par
make sim-par
make power-par

make drc
make lvs

These actions are summarized in more detail:

  • SRAM generation

    • make srams

    • Generated SRAM configs in OBJ_DIR/sram_generator-output.json (empty unless vlsi.inputs.sram_parameters is specified)

  • RTL simulation

    • make sim-rtl

    • Generated waveform in OBJ_DIR/sim-rtl-rundir/output.fsdb

  • Post-RTL Power simulation

    • make sim-rtl-to-power

    • make power-rtl

    • Generated power reports in OBJ_DIR/power-rtl-rundir/reports

  • Synthesis

    • make syn

    • Gate-level netlist in OBJ_DIR/syn-rundir/<design>.mapped.v

  • Post-Synthesis simulation

    • make syn-to-sim

    • make sim-syn

    • Generated waveform and register forcing ucli script in OBJ_DIR/sim-syn-rundir

  • Post-Synthesis Power simulation

    • make syn-to-power

    • make sim-syn-to-power

    • make power-syn

    • Generated power reports in OBJ_DIR/power-syn-rundir/reports

  • PnR

    • make syn-to-par

    • make par

    • LVS netlist (<design>.lvs.v) and GDS (<design>.gds) in OBJ_DIR/par-rundir

  • Post-PnR simulation

    • make par-to-sim

    • make sim-par

  • Post-PnR Power simulation

    • make par-to-power

    • make sim-par-to-power

    • make power-par

    • Generated power reports in OBJ_DIR/power-par-rundir

6.2.3.1. Flow Customization

If at any point you would like to use custom config files (that will override any previous configs), assign the extra Make variable to a space-separated list of these files. For example, to run the pass design with sky130 through the commercial flow, but run LVS with Cadence Pegasus instead of the default Siemens Calibre, simply run the following:

make extra="configs-tool/pegasus.yml" build

To use the Hammer step flow control, prepend redo- to any VLSI flow action, then assign the args Make variable to the appropriate Hammer command line args. For example, to only run the report_power step of the power-rtl action (i.e. bypass synthesis), run the following:

make args="--only_step report_power" redo-power-rtl

6.2.4. Custom Setups

If you’re not using a Berkeley EECS compute node, you can create your own environment setup.

  • Create an environment config similar to those in configs-env for your node to specify the CAD tool license servers and paths/versions of CAD tools and the PDK, and set the ENV_YML variable to this file.

  • The rest of the flow should be identical

6.2.4.1. ASAP7 Install

Clone the asap7 repo somewhere and reference the path in your ENV_YML config.

6.2.4.2. Sky130 Install

Refer to the Hammer Sky130 plugin README to install the Sky130 PDK, then reference the path in your ENV_YML config (only the technology.sky130.sky130A key is required).

6.2.5. Pipecleaning

We have provided several reference designs of increasing complexity to aid with pipecleaning your Hammer VLSI flow setup. These are summarized as follows, in order of complexity:

  • pass: single register

  • gcd: computes greatest common denominator, good for testing more complex logic

  • sram_wrapper_sky130: example wrapper for an SRAM instance in Sky130, useful for ensuring correct SRAM integration into flow

    • wraps any Sky130 SRAM instance available in hammer/hammer/technology/sky130/sram-cache.json

    • SRAM instance specified via defines in configs-design/sram_wrapper_sky130/common.yml

    • all SRAM configurations are loaded via these config fragments in configs-design/sram_wrapper_sky130/sky130.yml:

      •   # Compile all srams in our cache
  vlsi.inputs.sram_parameters: "../../../hammer/technology/sky130/sram-cache.json"
  vlsi.inputs.sram_parameters_meta: ["prependlocal", "transclude", "json2list"]