JTAG: Use new withClock way of overriding clocks (#1072)

* JTAG: Use new withClock way of overriding clocks

the override clock way is deprecated

* JTAG: use withClock instead of override clock

* JTAG:  extend Module for ClockedCounter

* JTAG: Don't use deprecated clock constructs

* JTAG: Remove another override_clock

* Rename "NegativeEdgeLatch"

because it's not a latch, it's just a register on the negative edge of the clock.

* Use the appropriately named NegEdgeReg

* JTAG: Rename another NegativeEdgeLatch

src/main/scala/jtag/JtagStateMachine.scala

@@ -4,6 +4,8 @@ package freechips.rocketchip.jtag
 
 import Chisel._
 import chisel3.{Input, Output}
+import chisel3.experimental.withReset
+
 import freechips.rocketchip.config.{Parameters}
 import freechips.rocketchip.util.{AsyncResetRegVec}
 import freechips.rocketchip.util.property._
@@ -69,26 +71,18 @@ object JtagState {
   *
   *
   */
-class JtagStateMachine(implicit val p: Parameters) extends Module(override_reset=Some(false.B)) {
+class JtagStateMachine(implicit val p: Parameters) extends Module() {
   class StateMachineIO extends Bundle {
     val tms = Input(Bool())
-    val currState = Output(JtagState.State.chiselType())
-
-    val jtag_reset = Input(Bool())
+    val currState = Output(JtagState.State.chiselType)
   }
   val io = IO(new StateMachineIO)
 
-  // val nextState = WireInit(JtagState.State.chiselType(), DontCare)
   val nextState = Wire(JtagState.State.chiselType())
-
   val currStateReg = Module (new AsyncResetRegVec(w = JtagState.State.width,
     init = JtagState.State.toInt(JtagState.TestLogicReset)))
-
-  currStateReg.clock := clock
-  currStateReg.reset := io.jtag_reset
   currStateReg.io.en := true.B
   currStateReg.io.d  := nextState
-
   val currState = currStateReg.io.q
 
   switch (currState) {
@@ -148,7 +142,8 @@ class JtagStateMachine(implicit val p: Parameters) extends Module(override_reset
   JtagState.State.all.foreach { s => 
     cover (currState === s.U && io.tms === true.B,  s"${s.toString}_tms_1", "JTAG; ${s.toString} with TMS = 1; State Transition from ${s.toString} with TMS = 1")
     cover (currState === s.U && io.tms === false.B, s"${s.toString}_tms_0", "JTAG; ${s.toString} with TMS = 0; State Transition from ${s.toString} with TMS = 0")
-    cover (currState === s.U && io.jtag_reset === true.B, s"${s.toString}_reset", "JTAG; ${s.toString} with reset; JTAG Reset asserted during ${s.toString")
+   cover (currState === s.U && reset.toBool === true.B, s"${s.toString}_reset", "JTAG; ${s.toString} with reset; JTAG Reset asserted during ${s.toString")
+ 
   }
 
 }

src/main/scala/jtag/JtagTap.scala

@@ -9,6 +9,8 @@ import scala.collection.SortedMap
 import Chisel._
 import chisel3.core.{Input, Output}
 import chisel3.util._
+import chisel3.experimental.withReset
+
 import freechips.rocketchip.config.Parameters
 
 /** JTAG signals, viewed from the master side
@@ -71,22 +73,26 @@ class JtagTapController(irLength: Int, initialInstruction: BigInt)(implicit val
 
   val tdo = Wire(Bool())  // 4.4.1c TDI should appear here uninverted after shifting
   val tdo_driven = Wire(Bool())
-  io.jtag.TDO.data := NegativeEdgeLatch(clock, tdo, name = Some("tdoReg"))  // 4.5.1a TDO changes on falling edge of TCK, 6.1.2.1d driver active on first TCK falling edge in ShiftIR and ShiftDR states
-  io.jtag.TDO.driven := NegativeEdgeLatch(clock, tdo_driven, name = Some("tdoeReg"))
+  io.jtag.TDO.data := NegEdgeReg(clock, tdo, name = Some("tdoReg"))  // 4.5.1a TDO changes on falling edge of TCK, 6.1.2.1d driver active on first TCK falling edge in ShiftIR and ShiftDR states
+  io.jtag.TDO.driven := NegEdgeReg(clock, tdo_driven, name = Some("tdoeReg"))
 
   //
   // JTAG state machine
   //
-  val stateMachine = Module(new JtagStateMachine)
-  stateMachine.io.tms := io.jtag.TMS
-  val currState = stateMachine.io.currState
-  io.output.state := stateMachine.io.currState
+
+  val currState = Wire(JtagState.State.chiselType)
 
   // At this point, the TRSTn should already have been
   // combined with any POR, and it should also be
   // synchronized to TCK.
   require(!io.jtag.TRSTn.isDefined, "TRSTn should be absorbed into jtckPOReset outside of JtagTapController.")
-  stateMachine.io.jtag_reset := io.control.jtag_reset
+  withReset(io.control.jtag_reset) {
+    val stateMachine = Module(new JtagStateMachine)
+    stateMachine.suggestName("stateMachine")
+    stateMachine.io.tms := io.jtag.TMS
+    currState := stateMachine.io.currState
+    io.output.state := stateMachine.io.currState
+  }
 
   //
   // Instruction Register
@@ -105,7 +111,7 @@ class JtagTapController(irLength: Int, initialInstruction: BigInt)(implicit val
   val updateInstruction = Wire(Bool())
 
   val nextActiveInstruction = Wire(UInt(irLength.W))
-  val activeInstruction = NegativeEdgeLatch(clock, nextActiveInstruction, updateInstruction, name = Some("irReg"))   // 7.2.1d active instruction output latches on TCK falling edge
+  val activeInstruction = NegEdgeReg(clock, nextActiveInstruction, updateInstruction, name = Some("irReg"))   // 7.2.1d active instruction output latches on TCK falling edge
 
   when (reset.toBool) {
     nextActiveInstruction := initialInstruction.U(irLength.W)

src/main/scala/jtag/Utils.scala

@@ -2,9 +2,9 @@
 
 package freechips.rocketchip.jtag
 
-//import chisel3._
 import Chisel._
 import chisel3.core.{Input, Output}
+import chisel3.experimental.withClock
 
 /** Bundle representing a tristate pin.
   */
@@ -13,40 +13,23 @@ class Tristate extends Bundle {
   val driven = Bool()  // active high, pin is hi-Z when driven is low
 }
 
-class NegativeEdgeLatch[T <: Data](clock: Clock, dataType: T)
-    extends Module(override_clock=Some(clock)) {
-  class IoClass extends Bundle {
-    val next = Input(dataType)
-    val enable = Input(Bool())
-    val output = Output(dataType)
-  }
-  val io = IO(new IoClass)
-
-  val reg = Reg(dataType)
-  when (io.enable) {
-    reg := io.next
-  }
-  io.output := reg
-}
-
 /** Generates a register that updates on the falling edge of the input clock signal.
   */
-object NegativeEdgeLatch {
+object NegEdgeReg {
   def apply[T <: Data](clock: Clock, next: T, enable: Bool=true.B, name: Option[String] = None): T = {
-    // TODO better init passing once in-module multiclock support improves
-    val latch_module = Module(new NegativeEdgeLatch((!clock.asUInt).asClock, next.cloneType))
-    name.foreach(latch_module.suggestName(_))
-    latch_module.io.next := next
-    latch_module.io.enable := enable
-    latch_module.io.output
+    // TODO pass in initial value as well
+    withClock((!clock.asUInt).asClock) {
+      val reg = RegEnable(next = next, enable = enable)
+      name.foreach{reg.suggestName(_)}
+      reg
+    }
   }
 }
 
 /** A module that counts transitions on the input clock line, used as a basic sanity check and
   * debug indicator clock-crossing designs.
   */
-class ClockedCounter(modClock: Clock, counts: BigInt, init: Option[BigInt])
-    extends Module(override_clock=Some(modClock)) {
+class ClockedCounter(counts: BigInt, init: Option[BigInt]) extends Module {
   require(counts > 0, "really?")
 
   val width = log2Ceil(counts)
@@ -65,7 +48,6 @@ class ClockedCounter(modClock: Clock, counts: BigInt, init: Option[BigInt])
   } .otherwise {
     count := count + 1.U
   }
-
  io.count := count
 }
 
@@ -73,11 +55,16 @@ class ClockedCounter(modClock: Clock, counts: BigInt, init: Option[BigInt])
   */
 object ClockedCounter {
   def apply (data: Bool, counts: BigInt, init: BigInt): UInt = {
-    val counter = Module(new ClockedCounter(data.asClock, counts, Some(init)))
+    withClock(data.asClock) {
+      val counter = Module(new ClockedCounter(counts, Some(init)))
       counter.io.count
     }
+  }
+
   def apply (data: Bool, counts: BigInt): UInt = {
-    val counter = Module(new ClockedCounter(data.asClock, counts, None))
+    withClock(data.asClock) {
+      val counter = Module(new ClockedCounter(counts, None))
       counter.io.count
     }
   }
+}