Merge pull request #1461 from ucb-bar/single-clock

Add singleclock broadcast clockbinder

generators/chipyard/src/main/scala/clocking/ClockBinders.scala

@@ -72,7 +72,7 @@ class WithPLLSelectorDividerClockGenerator(enable: Boolean = true) extends Overr
     }
   }
 })
- 
+
 // This passes all clocks through to the TestHarness
 class WithPassthroughClockGenerator extends OverrideLazyIOBinder({
   (system: HasChipyardPRCI) => {
@@ -102,6 +102,32 @@ class WithPassthroughClockGenerator extends OverrideLazyIOBinder({
   }
 })
 
+// Broadcasts a single clock IO to all clock domains. Ignores all requested frequencies
+class WithSingleClockBroadcastClockGenerator(freqMHz: Int = 100) extends OverrideLazyIOBinder({
+  (system: HasChipyardPRCI) => {
+    implicit val p = GetSystemParameters(system)
+
+    val clockGroupsAggregator = LazyModule(new ClockGroupAggregator("single_clock"))
+    val clockGroupsSourceNode = ClockGroupSourceNode(Seq(ClockGroupSourceParameters()))
+    system.chiptopClockGroupsNode :*= clockGroupsAggregator.node := clockGroupsSourceNode
+
+    InModuleBody {
+      val clock_wire = Wire(Input(Clock()))
+      val reset_wire = Wire(Input(AsyncReset()))
+      val (clock_io, clockIOCell) = IOCell.generateIOFromSignal(clock_wire, "clock", p(IOCellKey))
+      val (reset_io, resetIOCell) = IOCell.generateIOFromSignal(reset_wire, "reset", p(IOCellKey))
+
+      clockGroupsSourceNode.out.foreach { case (bundle, edge) =>
+        bundle.member.data.foreach { b =>
+          b.clock := clock_io
+          b.reset := reset_io
+        }
+      }
+      (Seq(ClockPort(() => clock_io, freqMHz), ResetPort(() => reset_io)), clockIOCell ++ resetIOCell)
+    }
+  }
+})
+
 class WithClockTapIOCells extends OverrideIOBinder({
   (system: CanHaveClockTap) => {
     system.clockTapIO.map { tap =>

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

@@ -0,0 +1,34 @@
+package chipyard
+
+import org.chipsalliance.cde.config.{Config}
+import freechips.rocketchip.diplomacy._
+import freechips.rocketchip.subsystem.{MBUS, SBUS}
+import testchipip.soc.{OBUS}
+
+//==================================================
+// This file contains examples of the different ways
+// clocks can be generated for chiypard designs
+//==================================================
+
+// The default constructs IOs for all requested clocks in the chiptopClockGroupsNode
+// Note: This is what designs inheriting from AbstractConfig do by default
+class DefaultClockingRocketConfig extends Config(
+  new chipyard.clocking.WithPassthroughClockGenerator ++
+  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
+  new chipyard.config.AbstractConfig)
+
+// This is a more physically realistic approach, normally we can't punch out a separate
+// pin for each clock domain. The standard "test chip" approach is to punch a few slow clock
+// inputs, integrate a PLL, and generate an array of selectors/dividers to configure the
+// clocks for each domain. See the source for WithPLLSelectorDividerClockGenerator for more info
+class ChipLikeClockingRocketConfig extends Config(
+  new chipyard.clocking.WithPLLSelectorDividerClockGenerator ++
+  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
+  new chipyard.config.AbstractConfig)
+
+// This merges all the clock domains in chiptopClockGroupsNode into one, then generates a single
+// clock input pin.
+class SingleClockBroadcastRocketConfig extends Config(
+  new chipyard.clocking.WithSingleClockBroadcastClockGenerator ++
+  new freechips.rocketchip.subsystem.WithNBigCores(1) ++
+  new chipyard.config.AbstractConfig)