Add EmptyChipTop example

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

@@ -17,3 +17,9 @@ class NoCoresConfig extends Config(
   new chipyard.config.WithNoDebug ++
   new chipyard.config.WithNoPLIC ++
   new chipyard.config.AbstractConfig)
+
+// A config that uses a empty chiptop module with no rocket-chip soc components
+class EmptyChipTopConfig extends Config(
+  new chipyard.example.WithEmptyChipTop ++
+  new chipyard.config.AbstractConfig             // since we aren't using rocket-chip, this doesn't do anything
+)

generators/chipyard/src/main/scala/example/EmptyChipTop.scala

@@ -0,0 +1,21 @@
+package chipyard.example
+
+import chisel3._
+
+import org.chipsalliance.cde.config._
+import freechips.rocketchip.diplomacy._
+import freechips.rocketchip.util.{DontTouch}
+
+import chipyard._
+import chipyard.harness.{BuildTop}
+
+class EmptyChipTop(implicit p: Parameters) extends LazyModule {
+  override lazy val module = new Impl
+  class Impl extends LazyRawModuleImp(this) with DontTouch {
+    // Your custom non-rocketchip-soc stuff here
+  }
+}
+
+class WithEmptyChipTop extends Config((site, here, up) => {
+  case BuildTop => (p: Parameters) => new EmptyChipTop()(p)
+})

generators/chipyard/src/main/scala/harness/HasHarnessInstantiators.scala

@@ -99,6 +99,7 @@ trait HasHarnessInstantiators {
     if (p(DontTouchChipTopPorts)) {
       duts.map(_ match {
         case d: DontTouch => d.dontTouchPorts()
+        case _ =>
       })
     }