Creating the NoC Configuration

The created NoC configuration will be: 3 × 2

 ---0———1---
|   |   |   |  
|   2———3   |
|   |   |   |
|   4———5   |
|   |   |   |
 ---6———7---

Steps to Create the NoC

Step 1: Switch to the branch

• Switch to the branch tutorial-asplos-2023:

  git checkout tutorial-asplos-2023
  

• Note: Source the environment setup script:

  source env.sh
  

• It is recommended to build a new Chipyard with Gemmini in the tutorial-asplos-2023 branch.

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Step 2: Edit the Configuration File

• Edit the file located at:

  chipyard/generators/chipyard/src/main/scala/config/TutorialConfigs.scala
  

• Add the following configuration under TutorialPhase9Config3dgemmini:

class TutorialPhase9Config3dgemmini extends Config(
  new constellation.soc.WithSbusNoC(constellation.protocol.TLNoCParams(
    constellation.protocol.DiplomaticNetworkNodeMapping(
      // inNodeMappings map master agents onto the NoC
      inNodeMapping = ListMap(
        "Core 0" -> 0,  // Rocket frontend + Gemmini
        "Core 1" -> 1,  // Rocket frontend + Gemmini
        "Core 2" -> 2,  // Rocket frontend + Gemmini
        "serial-tl" -> 0),
      // outNodeMappings map client agents (L2 banks) onto the NoC
      outNodeMapping = ListMap(
        "system[0]" -> 3, "system[1]" -> 4, "system[2]" -> 5, "system[3]" -> 6,
        "pbus" -> 7)),
    NoCParams(
      topology        = TerminalRouter(BidirectionalTorus2D(4, 2)),
      channelParamGen = (a, b) => UserChannelParams(Seq.fill(8) { UserVirtualChannelParams(4) }),
      routingRelation = BlockingVirtualSubnetworksRouting(TerminalRouterRouting(Mesh2DEscapeRouting()), 5, 1),
      skipValidationChecks = true
    )
  )) ++
  // ==========================================
  // DO NOT change below this line without    |
  // carefully adjusting the NoC config above |
  // ==========================================

  // add LeanGemmini to Rocket-core (as frontend)
  new chipyard.config.WithMultiRoCC ++
  new chipyard.config.WithMultiRoCCFromBuildRoCC(0,1,2) ++
  new gemmini.DefaultGemminiConfig(gemmini.GemminiConfigs.leanConfig.copy(use_dedicated_tl_port=false)) ++

  // Add 1 simple RocketCore+gemmini tile
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
  new freechips.rocketchip.subsystem.WithNBigCores(1) ++

  // Use 4 banks of L2 cache
  new freechips.rocketchip.subsystem.WithNBanks(4) ++

  new chipyard.config.AbstractConfig
)

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Step 3: Build the Configuration

• Navigate to the directory:

  chipyard/sims/verilator
  

• Build the configuration using the following command:

  make debug CONFIG=TutorialPhase9Config3dgemmini -j10
  

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Step 4: Check the RTL Files

• Verify the generated RTL files at:

  chipyard.TestHarness.TutorialPhase9Config3dgemmini/gen-collateral
  

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Step 5: Edit the Run Script

• Navigate to:

  chipyard/generators/gemmini
  

• Edit the script scripts/run-verilator.sh. Replace the existing binary with:

  ./simulator-chipyard-TutorialPhase9Config3dgemmini${DEBUG} $PK ${full_binary_path}
  

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Step 6: Run the Script

• Run the Verilator simulation with:

  ./scripts/run-verilator.sh —debug template
  

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Step 7: Analyze the Waveform

• The waveform file waveform.vcd will be generated at:

  chipyard/generators/gemmini/waveforms
  

• Open the waveform file using GTKWave for analysis.

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