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rocket-chip/src/main/scala/tilelink/Bus.scala
Wesley W. Terpstra b8098d18be
diplomacy: remove the :=? operator in favour of magic :*=* (#1139)
The reason for the :=? operator was for when you have an adapter chain
whose direction of cardinality you could not know. We used explicit
directives to tell these compositions which way to go.

Unfortunately, that makes the API leaky. You think the chain of adapters
is just one adapter, but you have to use strange Cardinality scopes to
use it. That's just bad.

The new :*=* just automagically figures it out from the graph.
2017-12-01 18:28:37 -08:00

86 lines
3.0 KiB
Scala

// See LICENSE.SiFive for license details.
package freechips.rocketchip.tilelink
import Chisel._
import freechips.rocketchip.config.{Field, Parameters}
import freechips.rocketchip.diplomacy._
case object TLBusDelayProbability extends Field[Double](0.0)
/** Specifies widths of various attachement points in the SoC */
trait TLBusParams {
val beatBytes: Int
val blockBytes: Int
val masterBuffering: BufferParams
val slaveBuffering: BufferParams
def beatBits: Int = beatBytes * 8
def blockBits: Int = blockBytes * 8
def blockBeats: Int = blockBytes / beatBytes
def blockOffset: Int = log2Up(blockBytes)
}
abstract class TLBusWrapper(params: TLBusParams, val busName: String)(implicit p: Parameters)
extends SimpleLazyModule with LazyScope with TLBusParams {
val beatBytes = params.beatBytes
val blockBytes = params.blockBytes
val masterBuffering = params.masterBuffering
val slaveBuffering = params.slaveBuffering
require(blockBytes % beatBytes == 0)
private val delayProb = p(TLBusDelayProbability)
protected val xbar = LazyModule(new TLXbar)
xbar.suggestName(busName)
private val master_buffer = LazyModule(new TLBuffer(masterBuffering))
master_buffer.suggestName(s"${busName}_master_TLBuffer")
private val slave_buffer = LazyModule(new TLBuffer(slaveBuffering))
slave_buffer.suggestName(s"${busName}_slave_TLBuffer")
private val slave_frag = LazyModule(new TLFragmenter(beatBytes, blockBytes))
slave_frag.suggestName(s"${busName}_slave_TLFragmenter")
private val slave_ww = LazyModule(new TLWidthWidget(beatBytes))
slave_ww.suggestName(s"${busName}_slave_TLWidthWidget")
private val delayedNode = if (delayProb > 0.0) {
val firstDelay = LazyModule(new TLDelayer(delayProb))
val flowDelay = LazyModule(new TLBuffer(BufferParams.flow))
val secondDelay = LazyModule(new TLDelayer(delayProb))
firstDelay.node :*= xbar.node
flowDelay.node :*= firstDelay.node
secondDelay.node :*= flowDelay.node
secondDelay.node
} else {
xbar.node
}
xbar.node :=* master_buffer.node
slave_buffer.node :*= delayedNode
slave_frag.node :*= slave_buffer.node
slave_ww.node :*= slave_buffer.node
protected def outwardNode: TLOutwardNode = delayedNode
protected def outwardBufNode: TLOutwardNode = slave_buffer.node
protected def outwardFragNode: TLOutwardNode = slave_frag.node
protected def outwardWWNode: TLOutwardNode = slave_ww.node
protected def inwardNode: TLInwardNode = xbar.node
protected def inwardBufNode: TLInwardNode = master_buffer.node
def bufferFromMasters: TLInwardNode = inwardBufNode
def bufferToSlaves: TLOutwardNode = outwardBufNode
def toSyncSlaves(name: Option[String] = None, addBuffers: Int = 0): TLOutwardNode = {
TLBuffer.chain(addBuffers).foldRight(outwardBufNode)(_ :*= _)
}
def toVariableWidthSlaves: TLOutwardNode = outwardFragNode
def toFixedWidthSlaves: TLOutwardNode = outwardWWNode
def toFixedWidthPorts: TLOutwardNode = outwardWWNode // TODO, do/don't buffer here; knowing we will after the necessary port conversions
}