add initialize argument to StreamFifo

[facebreeze]

Closes #

Context, Motivation & Description

Register constructed StreamFifo can be fully initialized when necessary.

Impact on code generation

Checklist

• Unit tests were added
• API changes are or will be documented:
  • using Scaladoc comments: /** */?
  • on RTD?
  • thanks to a new tracking issue on RTD?

[facebreeze]

Hi,
The test passed on scala 2.13.12, but failed on scala 2.11.12 with following error.

A null pointer access has been detected in the JVM.
This could happen when in your SpinalHDL description, you access an signal which is only defined further.
For instance :
  val result = Bool()
  result := a ^ b  //a and b can't be accessed there because they are only defined one line below (Software rule of execution order)
  val a,b = Bool()
          
[info] - port2 *** FAILED ***
[info]   java.lang.NullPointerException: Cannot throw exception because the return value of "spinal.lib.StreamFifo$$anonfun$apply$24.apply()" is null
[info]   at spinal.lib.StreamFifo$$anonfun$apply$24.apply(Stream.scala:1198)
[info]   at spinal.lib.StreamFifo$$anonfun$114$$anon$65$$anonfun$115.apply(Stream.scala:1264)
[info]   at spinal.lib.StreamFifo$$anonfun$114$$anon$65$$anonfun$115.apply(Stream.scala:1264)
[info]   at spinal.lib.Stream$$anon$29.<init>(Stream.scala:396)
[info]   at spinal.lib.Stream.m2sPipe(Stream.scala:392)
[info]   at spinal.lib.StreamFifo$$anonfun$114$$anon$65.<init>(Stream.scala:1264)
[info]   at spinal.lib.StreamFifo$$anonfun$114.apply(Stream.scala:1262)
[info]   at spinal.lib.StreamFifo$$anonfun$114.apply(Stream.scala:1262)
[info]   at spinal.core.internals.BooleanPimped.generate(Misc.scala:[285](https://github.com/SpinalHDL/SpinalHDL/actions/runs/13835797025/job/38710654563?pr=1680#step:5:286))
[info]   at spinal.lib.StreamFifo.<init>(Stream.scala:1262)

I have no idea how to fix this on scala 2.11.12. need help!!!

[Dolu1990]

Ahh i already have seen that kinda of scala weird behaviour.

It is related to initPayload : => T = null.asInstanceOf[T]
Sometimes it doesn't likes it :/ now sure why.

[facebreeze]

How about initPayload : => Option[T] = None ?

[Dolu1990]

Look good

[facebreeze]

Spinal error occurs for following StreamFifo instance:

case class FifoDemo() extends Component {
  val io = new Bundle {
    val input = slave Stream (Bool())
    val output = master Stream (Bool())
  }
  val fifo = new StreamFifo(cloneOf(io.input.payload), 1, initPayload = Some(io.input.payload.getZero))
  fifo.io.push << io.input
  io.output << fifo.io.pop
}

Error message:

HIERARCHY VIOLATION : Bool(x) is used to drive the (toplevel/fifo/io_push_rData :  Bool) := Bool(x) statement, but isn't readable in the fifo component
    spinal.lib.Stream$$anon$29.<init>(Stream.scala:426)
    spinal.lib.Stream.m2sPipe(Stream.scala:422)
    spinal.lib.StreamFifo$$anonfun$114$$anon$66.<init>(Stream.scala:1338)
    spinal.lib.StreamFifo$$anonfun$114.apply(Stream.scala:1335)
    spinal.lib.StreamFifo$$anonfun$114.apply(Stream.scala:1335)
    spinal.lib.StreamFifo.<init>(Stream.scala:1335)

Looks the problem happens on m2sPipe. Is it possible to change initPayload type of the m2sPipe ?

[Dolu1990]

is it possible to change initPayload type of the m2sPipe ?

into what ?

[facebreeze]

If change the initPayload : => T = null.asInstanceOf[T] of m2sPipe into initPayload : Option[T] = None, would it have an negative impact on those calling m2sPipe ?

[facebreeze]

Hi,
To avoid x propgating during simulation, it's necessary to initialize a pipeline which holds control information. For following code:

case class FrameCtrl() extends Bundle {
  val frameStart = Bool()
  val frameEnd = Bool()
}

case class StreamM2SPipe[T<:Data] (dataType: HardType[T], initPayload: Option[T] = None) extends Component {
  val io = new Bundle {
    val in = slave(Stream(dataType))
    val out = master(Stream(dataType))
  }
  initPayload match {
    case Some(initValue) => io.out << io.in.m2sPipe(holdPayload = true, initPayload = initValue.asInstanceOf[T])
    case None => io.out << io.in.m2sPipe(holdPayload = true)
  }
}

object StreamM2SPipeInst extends App {
  Config.spinal.generateVerilog(StreamM2SPipe(cloneOf(FrameCtrl()), Some(FrameCtrl().getZero)))
  //Config.spinal.generateVerilog(StreamM2SPipe(Bits(32 bits)))
}

Spinal errors:

`
Hardware assignement done outside any Component

Design's errors are listed above.
SpinalHDL compiler exit stack :

at spinal.core.SpinalExit$.apply(Misc.scala:459)
at spinal.core.SpinalError$.apply(Misc.scala:514)
at spinal.core.BaseType.assignFromImpl(BaseType.scala:233)
at spinal.core.Assignable.compositAssignFrom(Trait.scala:285)
at spinal.core.Assignable.compositAssignFrom$(Trait.scala:281)
at spinal.core.BaseType.compositAssignFrom(BaseType.scala:55)
at spinal.core.Data.assignFrom(Data.scala:417)
at spinal.core.Data.assignFrom$(Data.scala:417)
at spinal.core.BaseType.assignFrom(BaseType.scala:55)
at spinal.core.internals.BoolLiteral$.apply(Expression.scala:2624)
at spinal.core.BoolFactory.Bool(Bool.scala:36)
at spinal.core.BoolFactory.Bool$(Bool.scala:36)
at spinal.core.package$.Bool(core.scala:35)
at spinal.core.package$.False(core.scala:270)
at spinal.core.Bool.getZero(Bool.scala:301)
at spinal.core.Bool.getZero(Bool.scala:50)
at spinal.core.MultiData.$anonfun$getZero$1(MultiData.scala:221)
at spinal.core.MultiData.$anonfun$getZero$1$adapted(MultiData.scala:220)
at scala.collection.IterableOnceOps.foreach(IterableOnce.scala:576)
at scala.collection.IterableOnceOps.foreach$(IterableOnce.scala:574)
at scala.collection.AbstractIterable.foreach(Iterable.scala:933)
at spinal.core.MultiData.getZero(MultiData.scala:220)
at projectname.StreamM2SPipeInst$.$anonfun$new$3(StreamM2SPipe.scala:22)
at spinal.core.internals.PhaseCreateComponent.$anonfun$impl$319(Phase.scala:2883)
at spinal.core.fiber.Engine$.$anonfun$create$1(AsyncCtrl.scala:173)
at spinal.core.fiber.AsyncThread.$anonfun$jvmThread$1(AsyncThread.scala:60)
at spinal.core.fiber.EngineContext.$anonfun$newJvmThread$1(AsyncCtrl.scala:39)
at spinal.sim.JvmThread.run(SimManager.scala:51)

`

[Dolu1990]

Ahhh would realy need to have a lambda function in the mix :/

Because the Some(FrameCtrl().getZero) does try to generate hardware directly. (that would be delayed to withing the component via a lambda function)