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tilelink: cut WidthWidget from dependency on addr_lo

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This commit is contained in:
Wesley W. Terpstra 2017-07-25 19:09:54 -07:00
parent ede87c1f73
commit b2edca2a6b
1 changed files with 33 additions and 8 deletions
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41
src/main/scala/tilelink/WidthWidget.scala
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@ -78,7 +78,7 @@ class TLWidthWidget(innerBeatBytes: Int)(implicit p: Parameters) extends LazyMod
}
}
def split[T <: TLDataChannel](edgeIn: TLEdge, in: DecoupledIO[T], edgeOut: TLEdge, out: DecoupledIO[T]) = {
def split[T <: TLDataChannel](edgeIn: TLEdge, in: DecoupledIO[T], edgeOut: TLEdge, out: DecoupledIO[T], sourceMap: UInt => UInt) = {
val inBytes = edgeIn.manager.beatBytes
val outBytes = edgeOut.manager.beatBytes
val ratio = inBytes / outBytes
@ -104,7 +104,11 @@ class TLWidthWidget(innerBeatBytes: Int)(implicit p: Parameters) extends LazyMod
case a: TLBundleA => a.address(keepBits-1, dropBits)
case b: TLBundleB => b.address(keepBits-1, dropBits)
case c: TLBundleC => c.address(keepBits-1, dropBits)
case d: TLBundleD => d.addr_lo(keepBits-1, dropBits)
case d: TLBundleD => {
val sel = sourceMap(d.source)
val hold = Mux(first, sel, RegEnable(sel, first)) // a_first is not for whole xfer
hold & ~limit // if more than one a_first/xfer, the address must be aligned anyway
}
}
val index = sel | count
@ -130,7 +134,7 @@ class TLWidthWidget(innerBeatBytes: Int)(implicit p: Parameters) extends LazyMod
!last
}
def splice[T <: TLDataChannel](edgeIn: TLEdge, in: DecoupledIO[T], edgeOut: TLEdge, out: DecoupledIO[T]) = {
def splice[T <: TLDataChannel](edgeIn: TLEdge, in: DecoupledIO[T], edgeOut: TLEdge, out: DecoupledIO[T], sourceMap: UInt => UInt) = {
if (edgeIn.manager.beatBytes == edgeOut.manager.beatBytes) {
// nothing to do; pass it through
out <> in
@ -143,7 +147,7 @@ class TLWidthWidget(innerBeatBytes: Int)(implicit p: Parameters) extends LazyMod
edgeIn.data(cated.bits) := Cat(
edgeIn.data(repeated.bits)(edgeIn.manager.beatBytes*8-1, edgeOut.manager.beatBytes*8),
edgeIn.data(in.bits)(edgeOut.manager.beatBytes*8-1, 0))
repeat := split(edgeIn, cated, edgeOut, out)
repeat := split(edgeIn, cated, edgeOut, out, sourceMap)
} else {
// merge input to output
merge(edgeIn, in, edgeOut, out)
@ -151,12 +155,33 @@ class TLWidthWidget(innerBeatBytes: Int)(implicit p: Parameters) extends LazyMod
}
((io.in zip io.out) zip (node.edgesIn zip node.edgesOut)) foreach { case ((in, out), (edgeIn, edgeOut)) =>
splice(edgeIn, in.a, edgeOut, out.a)
splice(edgeOut, out.d, edgeIn, in.d)
// If the master is narrower than the slave, the D channel must be narrowed.
// This is tricky, because the D channel has no address data.
// Thus, you don't know which part of a sub-beat transfer to extract.
// To fix this, we record the relevant address bits for all sources.
// The assumption is that this sort of situation happens only where
// you connect a narrow master to the system bus, so there are few sources.
def sourceMap(source: UInt) = {
require (edgeOut.manager.beatBytes > edgeIn.manager.beatBytes)
val keepBits = log2Ceil(edgeOut.manager.beatBytes)
val dropBits = log2Ceil(edgeIn.manager.beatBytes)
val sources = Reg(Vec(edgeIn.client.endSourceId, UInt(width = keepBits-dropBits)))
val a_sel = in.a.bits.address(keepBits-1, dropBits)
when (in.a.fire()) {
sources(in.a.bits.source) := a_sel
}
val bypass = Bool(edgeIn.manager.minLatency == 0) && in.a.fire() && in.a.bits.source === source
Mux(bypass, a_sel, sources(source))
}
splice(edgeIn, in.a, edgeOut, out.a, sourceMap)
splice(edgeOut, out.d, edgeIn, in.d, sourceMap)
if (edgeOut.manager.anySupportAcquireB && edgeIn.client.anySupportProbe) {
splice(edgeOut, out.b, edgeIn, in.b)
splice(edgeIn, in.c, edgeOut, out.c)
splice(edgeOut, out.b, edgeIn, in.b, sourceMap)
splice(edgeIn, in.c, edgeOut, out.c, sourceMap)
out.e <> in.e
} else {
in.b.valid := Bool(false)