add multi-rocc and show small example

generators/example/src/main/scala/ConfigMixins.scala

@@ -106,3 +106,43 @@ class WithGPIOBoomRocketTop extends Config((site, here, up) => {
     top
   }
 })
+
+// ------------------
+// Multi-RoCC Support
+// ------------------
+
+/**
+ * Map from a hartId to a particular RoCC accelerator
+ */
+case object MultiRoCCKey extends Field[Map[Int, Seq[Parameters => LazyRoCC]]](Map.empty[Int, Seq[Parameters => LazyRoCC]])
+
+/**
+ * Mixin to enable different RoCCs based on the hartId
+ */
+class WithMultiRoCC extends Config((site, here, up) => {
+  case BuildRoCC => site(MultiRoCCKey).getOrElse(site(TileKey).hartId, Nil)
+})
+
+/**
+ * Mixin to add Hwachas to cores based on hart
+ *
+ * For ex:
+ *   Core 0, 1, 2, 3 have been defined earlier
+ *     with hartIds of 0, 1, 2, 3 respectively
+ *   And you call WithMultiRoCCHwacha(Seq(0,1))
+ *   Then Core 0 and 1 will get a Hwacha
+ *
+ * @param harts Seq of harts to specifiy which will get a Hwacha
+ */
+class WithMultiRoCCHwacha(harts: Seq[Int]) extends Config((site, here, up) => {
+  case MultiRoCCKey => {
+    require(harts.max <= ((up(RocketTilesKey, site).length + up(BoomTilesKey, site).length) - 1))
+    up(MultiRoCCKey, site) ++ harts.distinct.map{ i =>
+      (i -> Seq((p: Parameters) => {
+        implicit val q = p
+        implicit val v = implicitly[ValName]
+        LazyModule(new Hwacha()(p))
+      }))
+    }
+  }
+})

generators/example/src/main/scala/Configs.scala

@@ -216,6 +216,20 @@ class DualCoreBoomAndOneRocketConfig extends Config(
   new freechips.rocketchip.subsystem.WithNBigCores(1) ++
   new freechips.rocketchip.system.BaseConfig)
 
+class DualCoreBoomAndOneHwachaRocketConfig extends Config(
+  new WithNormalBoomAndRocketTop ++
+  new WithBootROM ++
+  new WithMultiRoCC ++
+  new WithMultiRoCCHwacha(Seq(0)) ++ // put Hwacha just on hart0 which was renumbered to Rocket
+  new boom.system.WithRenumberHarts ++
+  new hwacha.DefaultHwachaConfig ++
+  new boom.common.WithRVC ++
+  new boom.common.DefaultBoomConfig ++
+  new boom.system.WithNBoomCores(2) ++
+  new freechips.rocketchip.subsystem.WithoutTLMonitors ++
+  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
+  new freechips.rocketchip.system.BaseConfig)
+
 class RV32BoomAndRocketConfig extends Config(
   new WithNormalBoomRocketTop ++
   new WithBootROM ++