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tilelink: CacheCork now supports errors and BtoT upgrade

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- Acquire.BtoT succeeds with toT instantly
- AccessAckData.error causes Grant.toN.error
This commit is contained in:
Wesley W. Terpstra 2017-07-27 14:07:24 -07:00
parent 2e4f1611ed
commit 45189c3e30
1 changed files with 24 additions and 5 deletions
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29
src/main/scala/tilelink/CacheCork.scala
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@ -48,10 +48,15 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
// Put: 1, Release: 0 => AccessAck
// *: 0, Acquire: 1 => AccessAckData
// Take requests from A to A
val isPut = in.a.bits.opcode === PutFullData || in.a.bits.opcode === PutPartialData
// Take requests from A to A or D (if BtoT Acquire)
val a_a = Wire(out.a)
a_a <> in.a
val a_d = Wire(in.d)
val isPut = in.a.bits.opcode === PutFullData || in.a.bits.opcode === PutPartialData
val toD = in.a.bits.opcode === Acquire && in.a.bits.param === TLPermissions.BtoT
in.a.ready := Mux(toD, a_d.ready, a_a.ready)
a_a.valid := in.a.valid && !toD
a_a.bits := in.a.bits
a_a.bits.source := in.a.bits.source << 1 | Mux(isPut, UInt(1), UInt(0))
// Transform Acquire into Get
@ -61,6 +66,16 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
a_a.bits.source := in.a.bits.source << 1 | UInt(1)
}
// Upgrades are instantly successful
a_d.valid := in.a.valid && toD
a_d.bits.opcode := Grant
a_d.bits.param := TLPermissions.toT
a_d.bits.size := in.a.bits.size
a_d.bits.source := in.a.bits.source
a_d.bits.sink := UInt(0)
a_d.bits.data := UInt(0)
a_d.bits.error := Bool(false)
// Take ReleaseData from C to A; Release from C to D
val c_a = Wire(out.a)
c_a.valid := in.c.valid && in.c.bits.opcode === ReleaseData
@ -72,6 +87,7 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
c_a.bits.mask := edgeOut.mask(in.c.bits.address, in.c.bits.size)
c_a.bits.data := in.c.bits.data
// Releases without Data succeed instantly
val c_d = Wire(in.d)
c_d.valid := in.c.valid && in.c.bits.opcode === Release
c_d.bits.opcode := ReleaseAck
@ -99,7 +115,10 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
when (out.d.bits.opcode === AccessAckData && out.d.bits.source(0)) {
d_d.bits.opcode := GrantData
d_d.bits.param := TLPermissions.toT
// On Grant error, you do NOT get the permissions you asked for.
// We only enter this case from NtoT or NtoB, so that means use toN.
// (the BtoT case was handled by a_d)
d_d.bits.param := Mux(out.d.bits.error, TLPermissions.toN, TLPermissions.toT)
}
when (out.d.bits.opcode === AccessAck && !out.d.bits.source(0)) {
d_d.bits.opcode := ReleaseAck
@ -107,7 +126,7 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
// Combine the sources of messages into the channels
TLArbiter(TLArbiter.lowestIndexFirst)(out.a, (edgeOut.numBeats1(c_a.bits), c_a), (edgeOut.numBeats1(a_a.bits), a_a))
TLArbiter(TLArbiter.lowestIndexFirst)(in.d, (edgeIn .numBeats1(d_d.bits), d_d), (UInt(0), Queue(c_d, 2)))
TLArbiter(TLArbiter.lowestIndexFirst)(in.d, (edgeIn .numBeats1(d_d.bits), d_d), (UInt(0), Queue(c_d, 2)), (UInt(0), Queue(a_d, 2)))
// Tie off unused ports
in.b.valid := Bool(false)