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shave off channel select bits in MultiChannel router

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This commit is contained in:
Howard Mao 2015-11-02 22:39:50 -08:00
parent 096dbb3c2d
commit 3e906c8620
1 changed files with 45 additions and 5 deletions
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50
junctions/src/main/scala/nasti.scala
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@ -464,7 +464,6 @@ class NastiCrossbar(nMasters: Int, nSlaves: Int, routeSel: UInt => UInt)
object NastiMultiChannelRouter {
def apply(master: NastiIO, nChannels: Int)(implicit p: Parameters): Vec[NastiIO] = {
require(isPow2(nChannels), "Number of channels must be power of 2")
if (nChannels == 1) {
Vec(master)
} else {
@ -483,6 +482,47 @@ object NastiMultiChannelRouter {
}
}
class NastiMultiChannelRouter(nChannels: Int)
(implicit p: Parameters) extends NastiModule {
val io = new Bundle {
val master = (new NastiIO).flip
val slaves = Vec(new NastiIO, nChannels)
}
require(isPow2(nChannels), "Number of channels must be power of 2")
if (nChannels == 1) {
io.slaves.head <> io.master
} else {
val dataBytes = p(MIFDataBits) * p(MIFDataBeats) / 8
val selOffset = log2Up(dataBytes)
val selBits = log2Ceil(nChannels)
val blockOffset = selOffset + selBits
// Consecutive blocks route to alternating channels
val routeSel = (addr: UInt) => {
val sel = addr(blockOffset - 1, selOffset)
Vec.tabulate(nChannels)(i => sel === UInt(i)).toBits
}
val router = Module(new NastiRouter(nChannels, routeSel))
router.io.master <> io.master
def cutSelectBits(addr: UInt): UInt = {
Cat(addr(nastiXAddrBits - 1, blockOffset),
addr(selOffset - 1, 0))
}
io.slaves.zip(router.io.slave).foreach { case (outer, inner) =>
// Cut the selection bits out of the slave address channels
outer <> inner
outer.ar.bits.addr := cutSelectBits(inner.ar.bits.addr)
outer.aw.bits.addr := cutSelectBits(inner.aw.bits.addr)
}
}
}
class NastiInterconnectIO(val nMasters: Int, val nSlaves: Int)
(implicit p: Parameters) extends Bundle {
/* This is a bit confusing. The interconnect is a slave to the masters and
@ -547,10 +587,10 @@ class NastiRecursiveInterconnect(
}
slaveInd += subSlaves
case MemChannels(_, nchannels, _) =>
val routerSlaves = NastiMultiChannelRouter(xbarSlave, nchannels)
io.slaves.drop(slaveInd).take(nchannels).zip(routerSlaves).foreach {
case (s, m) => s <> m
}
val outChannels = Vec(io.slaves.drop(slaveInd).take(nchannels))
val router = Module(new NastiMultiChannelRouter(nchannels))
router.io.master <> xbarSlave
outChannels <> router.io.slaves
slaveInd += nchannels
}
}