riscv/rocket-chip
1
0
Fork 0
Code Releases Activity

tilelink2 ToAXI4: don't interlock R+W for non-FIFO masters (#822)

Browse Source 
idCount <= 1 implies that no more than one transaction can be inflight,
so there is no need to interlock R+W. However, when stripBits > 0, it is
possible for a non-FIFO master to have > 1 idCount. In this case, we
also don't need to interlock R+W.
This commit is contained in:
Wesley W. Terpstra 2017-06-26 17:54:17 -07:00 committed by GitHub
parent 72c46e6c05
commit 66f64a9759
1 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
src/main/scala/uncore/tilelink2/ToAXI4.scala
View File

@ -73,14 +73,14 @@ class TLToAXI4(beatBytes: Int, combinational: Boolean = true, adapterName: Optio
val sourceStall = Wire(Vec(edgeIn.client.endSourceId, Bool()))
val sourceTable = Wire(Vec(edgeIn.client.endSourceId, out.aw.bits.id))
val idStall = Wire(init = Vec.fill(edgeOut.master.endId) { Bool(false) })
var idCount = Array.fill(edgeOut.master.endId) { 0 }
var idCount = Array.fill(edgeOut.master.endId) { None:Option[Int] }
val maps = (edgeIn.client.clients.sortWith(TLToAXI4.sortByType) zip edgeOut.master.masters) flatMap { case (c, m) =>
for (i <- 0 until c.sourceId.size) {
val id = m.id.start + (if (c.requestFifo) 0 else (i >> stripBits))
sourceStall(c.sourceId.start + i) := idStall(id)
sourceTable(c.sourceId.start + i) := UInt(id)
idCount(id) = idCount(id) + 1
}
if (c.requestFifo) { idCount(m.id.start) = Some(c.sourceId.size) }
adapterName.map { n =>
val fmt = s"\t[%${axiDigits}d, %${axiDigits}d) <= [%${tlDigits}d, %${tlDigits}d) %s%s"
println(fmt.format(m.id.start, m.id.end, c.sourceId.start, c.sourceId.end, c.name, if (c.supportsProbe) " CACHE" else ""))
@ -199,8 +199,9 @@ class TLToAXI4(beatBytes: Int, combinational: Boolean = true, adapterName: Optio
val a_sel = UIntToOH(arw.id, edgeOut.master.endId).toBools
val d_sel = UIntToOH(Mux(r_wins, out.r.bits.id, out.b.bits.id), edgeOut.master.endId).toBools
val d_last = Mux(r_wins, out.r.bits.last, Bool(true))
(a_sel zip d_sel zip idStall zip idCount) filter { case (_, n) => n > 1 } foreach { case (((as, ds), s), n) =>
val count = RegInit(UInt(0, width = log2Ceil(n + 1)))
// If FIFO was requested, ensure that R+W ordering is preserved
(a_sel zip d_sel zip idStall zip idCount) filter { case (_, n) => n.map(_ > 1).getOrElse(false) } foreach { case (((as, ds), s), n) =>
val count = RegInit(UInt(0, width = log2Ceil(n.get + 1)))
val write = Reg(Bool())
val idle = count === UInt(0)
@ -209,7 +210,7 @@ class TLToAXI4(beatBytes: Int, combinational: Boolean = true, adapterName: Optio
count := count + inc.asUInt - dec.asUInt
assert (!dec || count =/= UInt(0)) // underflow
assert (!inc || count =/= UInt(n)) // overflow
assert (!inc || count =/= UInt(n.get)) // overflow
when (inc) { write := arw.wen }
s := !idle && write =/= arw.wen