tilelink2: include an abstract definition for register mapped devices

uncore/src/main/scala/tilelink2/RegField.scala

@@ -0,0 +1,37 @@
+// See LICENSE for license details.
+
+package uncore.tilelink2
+
+import Chisel._
+
+case class RegField(width: Int, read: RegField.ReadFn, write: RegField.WriteFn)
+object RegField
+{
+  type ReadFn = Bool => (Bool, UInt)
+  type WriteFn = (Bool, UInt) => Bool
+  type Map = (Int, Seq[RegField])
+
+  def apply(n: Int)                        : RegField = apply(n, noR, noW)
+  def apply(n: Int, rw: UInt)              : RegField = apply(n, regR(rw), regW(rw))
+  def apply(n: Int, r: UInt,   w: UInt)    : RegField = apply(n, regR(r),  regW(w))
+  def apply(n: Int, r: UInt,   w: WriteFn) : RegField = apply(n, regR(r),  w)
+  def apply(n: Int, r: ReadFn, w: UInt)    : RegField = apply(n, r,        regW(w))
+  def R(n: Int, r: ReadFn)                 : RegField = apply(n, r, noW)
+  def R(n: Int, r: UInt)                   : RegField = R(n, regR(r))
+  def W(n: Int, w: WriteFn)                : RegField = apply(n, noR, w)
+  def W(n: Int, w: UInt)                   : RegField = W(n, regW(w))
+
+  private val noR = (en: Bool) => (Bool(true), UInt(0))
+  private val noW = (en: Bool, in: UInt) => Bool(true)
+  private def regR(reg: UInt) = (en: Bool) => (Bool(true), reg)
+  private def regW(reg: UInt) = (en: Bool, in: UInt) =>
+  {
+     when (en) { reg := in }
+     Bool(true)
+  }
+}
+
+trait HasRegMap
+{
+  def regmap(mapping: RegField.Map*): Unit
+}