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tilelink2 RAMModel: model the state a RAM would have for Put+Gets

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This commit is contained in:
Wesley W. Terpstra 2016-09-09 20:57:20 -07:00
parent 488b93d146
commit 17f7ab18de
1 changed files with 194 additions and 0 deletions
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src/main/scala/uncore/tilelink2/RAMModel.scala Normal file
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// See LICENSE for license details.
package uncore.tilelink2
import Chisel._
import chisel3.util.LFSR16
class TLRAMModel extends LazyModule
{
val node = TLIdentityNode()
lazy val module = new LazyModuleImp(this) {
val io = new Bundle {
val in = node.bundleIn
val out = node.bundleOut
}
// Pass through all signals unchanged
io.out <> io.in
require (io.out.size == 1) // !!! support multiple clients
val edge = node.edgesIn(0)
val endAddress = edge.manager.maxAddress + 1
val endSourceId = edge.client.endSourceId
val maxTransfer = edge.manager.maxTransfer
val beatBytes = edge.manager.beatBytes
val endAddressHi = (endAddress / beatBytes).intValue
val maxLgBeats = log2Up(maxTransfer/beatBytes)
val shift = log2Ceil(beatBytes)
val decTrees = log2Ceil(maxTransfer/beatBytes)
val addressBits = log2Up(endAddress)
val countBits = log2Up(endSourceId)
val sizeBits = edge.bundle.sizeBits
class ByteMonitor extends Bundle {
val valid = Bool()
val value = UInt(width = 8)
}
class FlightMonitor extends Bundle {
val base = UInt(width = addressBits)
val size = UInt(width = sizeBits)
val opcode = UInt(width = 3)
}
// !!! Must somehow power-on with these all initialized with 0
val shadow = Seq.fill(beatBytes) { Mem(endAddressHi, new ByteMonitor) }
val inc_bytes = Seq.fill(beatBytes) { Mem(endAddressHi, UInt(width = countBits)) }
val dec_bytes = Seq.fill(beatBytes) { Mem(endAddressHi, UInt(width = countBits)) }
val inc_trees = Seq.tabulate(decTrees) { i => Mem(endAddressHi >> (i+1), UInt(width = countBits)) }
val dec_trees = Seq.tabulate(decTrees) { i => Mem(endAddressHi >> (i+1), UInt(width = countBits)) }
// Don't care on power-up
val flight = Reg(Vec(endSourceId, new FlightMonitor))
// Process A access requests
val a = RegNext(io.in(0).a)
val a_beats1 = edge.numBeats1(a.bits)
val a_size = edge.size(a.bits)
val a_sizeOH = UIntToOH(a_size)
val a_counter = RegInit(UInt(0, width = maxLgBeats))
val a_counter1 = a_counter - UInt(1)
val a_first = a_counter === UInt(0)
val a_addr_hi = a.bits.addr_hi | (a_beats1 & ~a_counter1)
val a_base = edge.address(a.bits)
val a_mask = edge.mask(a_base, a_size)
// What is the request?
val a_flight = Wire(new FlightMonitor)
a_flight.base := a_base
a_flight.size := a_size
a_flight.opcode := a.bits.opcode
// Grab the concurrency state we need
val a_inc_bytes = inc_bytes.map(_.read(a_addr_hi))
val a_dec_bytes = dec_bytes.map(_.read(a_addr_hi))
val a_inc_trees = inc_trees.zipWithIndex.map{ case (m, i) => m.read(a_addr_hi >> (i+1)) }
val a_dec_trees = dec_trees.zipWithIndex.map{ case (m, i) => m.read(a_addr_hi >> (i+1)) }
val a_inc_tree = a_inc_trees.fold(UInt(0))(_ + _)
val a_dec_tree = a_dec_trees.fold(UInt(0))(_ + _)
val a_inc = a_inc_bytes.map(_ + a_inc_tree)
val a_dec = a_dec_bytes.map(_ + a_dec_tree)
when (a.fire()) {
// Record the request so we can handle it's response
flight(a.bits.source) := a_flight
a_counter := Mux(a_first, a_beats1, a_counter1)
// !!! atomics
assert (a.bits.opcode =/= TLMessages.Acquire)
// Increase the per-byte flight counter for the whole transaction
when (a_first && a.bits.opcode =/= TLMessages.Hint) {
when (a_size <= UInt(shift)) {
for (i <- 0 until beatBytes) {
when (a_mask(i)) { // not a.bits.mask; the full mask
inc_bytes(i).write(a_addr_hi, a_inc_bytes(i) + UInt(1))
}
}
}
for (i <- 0 until inc_trees.size) {
when (a_sizeOH(i+shift+1)) {
inc_trees(i).write(a_addr_hi >> (i+1), a_inc_trees(i) + UInt(1))
}
}
}
when (a.bits.opcode === TLMessages.PutFullData || a.bits.opcode === TLMessages.PutPartialData) {
for (i <- 0 until beatBytes) {
val set = Wire(new ByteMonitor)
val busy = a_inc(i) - a_dec(i) - (!a_first).asUInt
set.valid := busy === UInt(0)
set.value := a.bits.data(8*(i+1)-1, 8*i)
when (a.bits.mask(i)) {
shadow(i).write(a_addr_hi, set)
printf("P 0x%x := 0x%x #%d\n", a_addr_hi << shift | UInt(i), set.value, busy)
}
}
}
}
// Process D access responses
val d = RegNext(io.out(0).d)
val d_bypass = a.valid && d.bits.source === a.bits.source
val d_flight = Mux(d_bypass, a_flight, flight(d.bits.source))
val d_beats1 = edge.numBeats1(d.bits)
val d_size = edge.size(d.bits)
val d_sizeOH = UIntToOH(d_size)
val d_counter = RegInit(UInt(0, width = maxLgBeats))
val d_counter1 = d_counter - UInt(1)
val d_first = d_counter === UInt(0)
val d_last = d_counter === UInt(1) || d_beats1 === UInt(0)
val d_base = d_flight.base
val d_addr_hi = d_base >> shift | (d_beats1 & ~d_counter1)
val d_mask = edge.mask(d_base, d_size)
// Grab the concurrency state we need
val d_inc_bytes = inc_bytes.map(_.read(d_addr_hi))
val d_dec_bytes = dec_bytes.map(_.read(d_addr_hi))
val d_inc_trees = inc_trees.zipWithIndex.map{ case (m, i) => m.read(d_addr_hi >> (i+1)) }
val d_dec_trees = dec_trees.zipWithIndex.map{ case (m, i) => m.read(d_addr_hi >> (i+1)) }
val d_inc_tree = d_inc_trees.fold(UInt(0))(_ + _)
val d_dec_tree = d_dec_trees.fold(UInt(0))(_ + _)
val d_inc = d_inc_bytes.map(_ + d_inc_tree)
val d_dec = d_dec_bytes.map(_ + d_dec_tree)
val d_shadow = shadow.map(_.read(d_addr_hi))
when (d.fire()) {
assert (d_size === d_flight.size)
d_counter := Mux(d_first, d_beats1, d_counter1)
when (d_flight.opcode === TLMessages.Hint) {
assert (d.bits.opcode === TLMessages.HintAck)
}
// Decreaes the per-byte flight counter for the whole transaction
when (d_last && d_flight.opcode =/= TLMessages.Hint) {
when (d_size <= UInt(shift)) {
for (i <- 0 until beatBytes) {
when (d_mask(i)) {
dec_bytes(i).write(d_addr_hi, d_dec_bytes(i) + UInt(1))
}
}
}
for (i <- 0 until dec_trees.size) {
when (d_sizeOH(i+shift+1)) {
dec_trees(i).write(d_addr_hi >> (i+1), d_dec_trees(i) + UInt(1))
}
}
}
when (d_flight.opcode === TLMessages.PutFullData || d_flight.opcode === TLMessages.PutPartialData) {
assert (d.bits.opcode === TLMessages.AccessAck)
}
// !!! atomics
when (d_flight.opcode === TLMessages.Get) {
assert (d.bits.opcode === TLMessages.AccessAckData)
for (i <- 0 until beatBytes) {
val got = d.bits.data(8*(i+1)-1, 8*i)
val shadow = Wire(init = d_shadow(i))
when (d_mask(i)) {
when (!shadow.valid) {
printf("G 0x%x := undefined due to concurrent accesses\n", d_addr_hi << shift | UInt(i))
} .otherwise {
printf("G 0x%x := 0x%x\n", d_addr_hi << shift | UInt(i), shadow.value)
assert (shadow.value === got)
}
}
}
}
}
}
}