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Minor stylistic and QoR improvements to PLIC

This commit is contained in:
Andrew Waterman 2017-04-27 19:35:20 -07:00
parent 3d0ed80ef6
commit 7c70aa593e
1 changed files with 15 additions and 15 deletions
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30
src/main/scala/uncore/devices/Plic.scala
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@ -12,6 +12,7 @@ import uncore.tilelink2._
import config._
import scala.math.min
import tile.XLen
import util._
class GatewayPLICIO extends Bundle {
val valid = Bool(OUTPUT)
@ -76,7 +77,7 @@ class TLPLIC(maxPriorities: Int, address: BigInt = 0xC000000)(implicit p: Parame
device = device,
beatBytes = p(XLen)/8,
undefZero = false,
concurrency = 1) // Work around the enable -> claim hazard
concurrency = 1) // limiting concurrency handles RAW hazards on claim registers
val intnode = IntNexusNode(
numSourcePorts = 0 to 1024,
@ -128,11 +129,11 @@ class TLPLIC(maxPriorities: Int, address: BigInt = 0xC000000)(implicit p: Parame
require(nHarts > 0 && nHarts <= PLICConsts.maxHarts)
// For now, use LevelGateways for all TL2 interrupts
val gateways = Vec(interrupts.map { case i =>
val gateways = Vec((false.B +: interrupts).map { case i =>
val gateway = Module(new LevelGateway)
gateway.io.interrupt := i
gateway.io.plic
} ++ (if (interrupts.isEmpty) Some(Wire(new GatewayPLICIO)) else None))
})
val priority =
if (nPriorities > 0) Reg(Vec(nDevices+1, UInt(width=log2Up(nPriorities+1))))
@ -143,7 +144,7 @@ class TLPLIC(maxPriorities: Int, address: BigInt = 0xC000000)(implicit p: Parame
val pending = Reg(init=Vec.fill(nDevices+1){Bool(false)})
val enables = Reg(Vec(nHarts, Vec(nDevices+1, Bool())))
for ((p, g) <- pending.tail zip gateways) {
for ((p, g) <- pending zip gateways) {
g.ready := !p
g.complete := false
when (g.valid) { p := true }
@ -152,19 +153,18 @@ class TLPLIC(maxPriorities: Int, address: BigInt = 0xC000000)(implicit p: Parame
def findMax(x: Seq[UInt]): (UInt, UInt) = {
if (x.length > 1) {
val half = 1 << (log2Ceil(x.length) - 1)
val lMax = findMax(x take half)
val rMax = findMax(x drop half)
val useLeft = lMax._1 >= rMax._1
(Mux(useLeft, lMax._1, rMax._1), Mux(useLeft, lMax._2, UInt(half) | rMax._2))
val left = findMax(x take half)
val right = findMax(x drop half)
MuxT(left._1 >= right._1, left, (right._1, UInt(half) | right._2))
} else (x.head, UInt(0))
}
val maxDevs = Reg(Vec(nHarts, UInt(width = log2Up(pending.size))))
for (hart <- 0 until nHarts) {
val effectivePriority =
for (((p, en), pri) <- (pending zip enables(hart) zip priority).tail)
yield Cat(p && en, pri)
val (maxPri, maxDev) = findMax((UInt(1) << priority(0).getWidth) +: effectivePriority)
val effectivePriority = (UInt(1) << priority(0).getWidth) +:
(for (((p, en), pri) <- (pending zip enables(hart) zip priority).tail)
yield Cat(p && en, pri))
val (maxPri, maxDev) = findMax(effectivePriority)
maxDevs(hart) := maxDev
harts(hart) := Reg(next = maxPri) > Cat(UInt(1), threshold(hart))
@ -185,13 +185,13 @@ class TLPLIC(maxPriorities: Int, address: BigInt = 0xC000000)(implicit p: Parame
RegReadFn { valid =>
when (valid) {
pending(maxDevs(i)) := Bool(false)
maxDevs(i) := UInt(0) // flush pipeline
}
(Bool(true), maxDevs(i))
},
RegWriteFn { (valid, data) =>
when (valid && enables(i)(data)) {
gateways(data - UInt(1)).complete := Bool(true)
val irq = data.extract(log2Ceil(nDevices+1)-1, 0)
when (valid && enables(i)(irq)) {
gateways(irq).complete := Bool(true)
}
Bool(true)
}