subsystem: refine Attachable trait to be based on LocationMap

src/main/scala/subsystem/Attachable.scala

@@ -0,0 +1,55 @@
+// See LICENSE.SiFive for license details.
+
+package freechips.rocketchip.subsystem
+
+import scala.language.dynamics
+import freechips.rocketchip.config.Parameters
+import freechips.rocketchip.diplomacy.{LazyModule, LazyScope}
+import freechips.rocketchip.diplomaticobjectmodel.HasLogicalTreeNode
+import freechips.rocketchip.prci.ClockGroupEphemeralNode
+import freechips.rocketchip.tilelink.TLBusWrapper
+import freechips.rocketchip.util.{Location, LocationMap}
+
+/** These traits are intended to make it possible to configure to which
+  * buses optional devices are attached, even after a subsystem has been instantiated.
+  * Consider them experimental for now.
+  */
+
+trait LazyScopeWithParameters extends LazyScope { this: LazyModule =>
+  implicit val p: Parameters
+}
+
+trait HasLogicalHierarchy extends LazyScopeWithParameters with HasLogicalTreeNode { this: LazyModule => }
+
+trait HasPRCILocations extends HasLogicalHierarchy { this: LazyModule =>
+  implicit val asyncClockGroupsNode: ClockGroupEphemeralNode
+  val ibus: InterruptBusWrapper
+}
+
+// TODO make this trait extend Dynamic itself and add the locations to anyLocationMap?
+trait HasLocations extends HasPRCILocations { this: LazyModule =>
+  val anyLocationMap = new LocationMap[Any]
+  def selectDynamic(name: String): Any = anyLocationMap.selectDynamic(name)
+  def updateDynamic(name: String)(value: Any): Unit = anyLocationMap.updateDynamic(name)(value)
+
+  val tlBusWrapperLocationMap = new LocationMap[TLBusWrapper]
+  def locateTLBusWrapper(location: TLBusWrapperLocation): TLBusWrapper = locateTLBusWrapper(location.name)
+  def locateTLBusWrapper(name: String): TLBusWrapper = tlBusWrapperLocationMap.selectDynamic(name)
+}
+
+trait CanInstantiateWithinContext {
+  def instantiate(context: HasLocations)(implicit p: Parameters): Unit
+}
+
+trait CanConnectWithinContext {
+  def connect(context: HasLocations)(implicit p: Parameters): Unit
+}
+
+/** Attachable things provide a standard interface by which other things may attach themselves to this target.
+  * Right now the trait is mostly for backwards compatibility, and in case it eventually becomes valuable
+  * to be able to define additional resources available to agents trying to attach themselves, other than
+  * what is being made available via LocationMaps in trait HasLocations.
+  */
+trait Attachable extends HasLocations { this: LazyModule =>
+  def locateTLBusWrapper(location: TLBusWrapperLocation): TLBusWrapper
+}

src/main/scala/subsystem/BaseSubsystem.scala

@@ -45,26 +45,8 @@ abstract class BareSubsystemModuleImp[+L <: BareSubsystem](_outer: L) extends La
   println(outer.dts)
 }
 
-/** These traits are intended to make it possible to configure to which
-  * buses optional devices are attached, even after a subsystem has been instantiated.
-  * Consider them experimental for now.
-  */
-
-trait Attachable extends LazyScope
-    with HasLogicalTreeNode
-    with HasBusLocationFunction { this: LazyModule =>
-  implicit val p: Parameters
-  implicit val asyncClockGroupsNode: ClockGroupEphemeralNode
-  val ibus: InterruptBusWrapper
-}
-
-trait HasBusLocationFunction {
-  type BusLocationFunction = PartialFunction[TLBusWrapperLocation, TLBusWrapper]
-  def locateTLBusWrapper: BusLocationFunction
-}
-
-/** This class the cases matched in baseBusLocateFunc below.
-  * Extend/override them to offer novel attachment locations.
+/** This trait contains the cases matched in baseBusAttachmentFunc below.
+  * Extend/override them to offer novel attachment locations in subclasses of BaseSubsystem.
   */
 class TLBusWrapperLocation(name: String) extends Location[TLBusWrapper](name)
 case object SBUS extends TLBusWrapperLocation("subsystem_sbus")
@@ -95,14 +77,6 @@ abstract class BaseSubsystem(implicit p: Parameters) extends BareSubsystem
   val mbus = LazyModule(new MemoryBus(p(MemoryBusKey)))
   val cbus = LazyModule(new PeripheryBus(p(ControlBusKey), "subsystem_cbus"))
 
-  def locateTLBusWrapper: BusLocationFunction = {
-    case SBUS => sbus
-    case PBUS => pbus
-    case FBUS => fbus
-    case MBUS => mbus
-    case CBUS => cbus
-  }
-
   implicit val asyncClockGroupsNode = p(AsyncClockGroupsKey)
   val async_clock_groups =
     p(SubsystemDriveAsyncClockGroupsKey)