Add ManagerToClientStatelessBridge
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uncore/src/main/scala/agents/StatelessBridge.scala
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61
uncore/src/main/scala/agents/StatelessBridge.scala
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// See LICENSE for license details.
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package uncore.agents
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import Chisel._
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import uncore.coherence._
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import uncore.tilelink._
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import uncore.constants._
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import uncore.devices._
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import cde.{Parameters, Field, Config}
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/** The ManagerToClientStateless Bridge does not maintain any state for the messages
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* which pass through it. It simply passes the messages back and forth without any
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* tracking or translation.
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*
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* This can reduce area and timing in very constrained situations:
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* - The Manager and Client implement the same coherence protocol
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* - There are no probe or finish messages.
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* - The outer transaction ID is large enough to handle all possible inner
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* transaction IDs, such that no remapping state must be maintained.
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*
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*/
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class ManagerToClientStatelessBridge(implicit p: Parameters) extends HierarchicalCoherenceAgent()(p) {
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val icid = io.inner.acquire.bits.client_id.getWidth
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val ixid = io.inner.acquire.bits.client_xact_id.getWidth
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val oxid = io.outer.acquire.bits.client_xact_id.getWidth
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// Stateless Bridge is only usable in certain constrained situations.
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// Sanity check its usage here.
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// Additional requirements are that the inner and outer Coherence policies
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// are the same (e.g. MEI != MESI), and that NTiles == 1,
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// but this is not checked here.
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require (p(NTiles) == 1)
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require(icid + ixid <= oxid)
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require(icid == io.inner.release.bits.client_id.getWidth)
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require(ixid == io.inner.release.bits.client_xact_id.getWidth)
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require(oxid == io.outer.release.bits.client_xact_id.getWidth)
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io.outer.acquire.valid := io.inner.acquire.valid
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io.inner.acquire.ready := io.outer.acquire.ready
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io.outer.acquire.bits := io.inner.acquire.bits
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io.outer.acquire.bits.client_xact_id := Cat(io.inner.acquire.bits.client_id, io.inner.acquire.bits.client_xact_id)
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io.outer.release.valid := io.inner.release.valid
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io.inner.release.ready := io.outer.release.ready
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io.outer.release.bits := io.inner.release.bits
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io.outer.release.bits.client_xact_id := Cat(io.inner.release.bits.client_id, io.inner.release.bits.client_xact_id)
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io.inner.grant.valid := io.outer.grant.valid
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io.outer.grant.ready := io.inner.grant.ready
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io.inner.grant.bits := io.outer.grant.bits
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io.inner.grant.bits.client_xact_id := io.outer.grant.bits.client_xact_id(ixid-1, 0)
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io.inner.grant.bits.client_id := io.outer.grant.bits.client_xact_id(icid+ixid-1, ixid)
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io.inner.probe.valid := Bool(false)
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io.inner.finish.ready := Bool(true)
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}
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