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Replace nbcache manipulation of meta state bits with abstracted functions

This commit is contained in:
Henry Cook 2012-02-15 13:54:36 -08:00
parent 619929eba1
commit 124efe5281
2 changed files with 40 additions and 47 deletions
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2
rocket/src/main/scala/coherence.scala
View File

@ -76,7 +76,7 @@ trait ThreeStateIncoherence {
def newStateOnFlush() = tileInvalid
def newState(cmd: Bits, state: UFix): UFix = {
val (read, write) = cpuCmdToRW(cmd)
Mux(write, tileDirty, Mux(read, Mux(state === tileDirty, tileDirty, tileClean), tileInvalid))
Mux(write, tileDirty, Mux(read, Mux(state === tileDirty, tileDirty, tileClean), state))
}
def newStateOnHit(cmd: Bits, state: UFix): UFix = newState(cmd, state)
def newStateOnPrimaryMiss(cmd: Bits): UFix = newState(cmd, tileInvalid)

85
rocket/src/main/scala/nbdcache.scala
View File

@ -1,9 +1,7 @@
package Top {
import Chisel._
import Node._;
import Constants._;
import scala.math._;
import Constants._
class ioReplacementWayGen extends Bundle {
val pick_new_way = Bool(dir = INPUT)
@ -18,7 +16,7 @@ class RandomReplacementWayGen extends Component {
{
val rand_way_id = UFix(width = log2up(NWAYS))
rand_way_id := LFSR16(io.pick_new_way)(log2up(NWAYS)-1,0)
when (rand_way_id >= UFix(NWAYS, width = log2up(NWAYS))) { io.way_id := UFix(0, width = log2up(NWAYS)) }
when (rand_way_id >= UFix(NWAYS, width = log2up(NWAYS)+1)) { io.way_id := UFix(0, width = log2up(NWAYS)) }
.otherwise { io.way_id := rand_way_id }
}
else io.way_id := UFix(0)
@ -148,8 +146,7 @@ class WritebackReq extends Bundle {
}
class MetaData extends Bundle {
val valid = Bool()
val dirty = Bool()
val state = UFix(width = 2)
val tag = Bits(width = TAG_BITS)
}
@ -164,7 +161,7 @@ class MetaArrayArrayReq extends Bundle {
val way_en = Bits(width = NWAYS)
}
class MSHR(id: Int) extends Component {
class MSHR(id: Int) extends Component with ThreeStateIncoherence {
val io = new Bundle {
val req_pri_val = Bool(INPUT)
val req_pri_rdy = Bool(OUTPUT)
@ -191,7 +188,7 @@ class MSHR(id: Int) extends Component {
}
val valid = Reg(resetVal = Bool(false))
val dirty = Reg { Bool() }
val state = Reg { UFix() }
val requested = Reg { Bool() }
val refilled = Reg { Bool() }
val ppn = Reg { Bits() }
@ -200,8 +197,8 @@ class MSHR(id: Int) extends Component {
val req_load = (io.req_cmd === M_XRD) || (io.req_cmd === M_PFR)
val req_use_rpq = (io.req_cmd != M_PFR) && (io.req_cmd != M_PFW)
val next_dirty = dirty || io.req_sec_val && io.req_sec_rdy && !req_load
val sec_rdy = io.idx_match && !refilled && (dirty || !requested || req_load)
val next_state = Mux(io.req_sec_val && io.req_sec_rdy, newStateOnSecondaryMiss(io.req_cmd, state), state)
val sec_rdy = io.idx_match && !refilled && (needsWriteback(state) || !requested || req_load)
// XXX why doesn't this work?
// val rpq = (new queue(NRPQ)) { new RPQEntry() }
@ -225,7 +222,7 @@ class MSHR(id: Int) extends Component {
when (io.req_pri_val && io.req_pri_rdy) {
valid := Bool(true)
dirty := !req_load
state := newStateOnPrimaryMiss(io.req_cmd)
requested := Bool(false)
refilled := Bool(false)
ppn := io.req_ppn
@ -242,7 +239,7 @@ class MSHR(id: Int) extends Component {
when (io.meta_req.valid && io.meta_req.ready) {
valid := Bool(false)
}
dirty := next_dirty
state := next_state
}
io.idx_match := valid && (idx_ === io.req_idx)
@ -255,8 +252,7 @@ class MSHR(id: Int) extends Component {
io.meta_req.valid := valid && refilled && !rpq.io.deq.valid
io.meta_req.bits.inner_req.rw := Bool(true)
io.meta_req.bits.inner_req.idx := idx_
io.meta_req.bits.inner_req.data.valid := Bool(true)
io.meta_req.bits.inner_req.data.dirty := dirty
io.meta_req.bits.inner_req.data.state := state
io.meta_req.bits.inner_req.data.tag := ppn
io.meta_req.bits.way_en := way_oh_
@ -466,7 +462,7 @@ class WritebackUnit extends Component {
io.mem_req_data := wbq.io.deq.bits
}
class FlushUnit(lines: Int) extends Component {
class FlushUnit(lines: Int) extends Component with ThreeStateIncoherence{
val io = new Bundle {
val req = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }
val resp = (new ioDecoupled) { Bits(width = DCACHE_TAG_BITS) }.flip()
@ -493,7 +489,7 @@ class FlushUnit(lines: Int) extends Component {
}
is(s_ready) { when (io.req.valid) { state := s_meta_read; tag := io.req.bits } }
is(s_meta_read) { when (io.meta_req.ready) { state := s_meta_wait } }
is(s_meta_wait) { state := Mux(io.meta_resp.valid && io.meta_resp.dirty && !io.wb_req.ready, s_meta_read, s_meta_write) }
is(s_meta_wait) { state := Mux(needsWriteback(io.meta_resp.state) && !io.wb_req.ready, s_meta_read, s_meta_write) }
is(s_meta_write) {
when (io.meta_req.ready) {
state := Mux(~way_cnt === UFix(0) && ~idx_cnt === UFix(0), s_done, s_meta_read);
@ -511,10 +507,9 @@ class FlushUnit(lines: Int) extends Component {
io.meta_req.bits.way_en := UFixToOH(way_cnt, NWAYS)
io.meta_req.bits.inner_req.idx := idx_cnt
io.meta_req.bits.inner_req.rw := (state === s_meta_write) || (state === s_reset)
io.meta_req.bits.inner_req.data.valid := Bool(false)
io.meta_req.bits.inner_req.data.dirty := Bool(false)
io.meta_req.bits.inner_req.data.state := newStateOnFlush()
io.meta_req.bits.inner_req.data.tag := UFix(0)
io.wb_req.valid := state === s_meta_wait && io.meta_resp.valid && io.meta_resp.dirty
io.wb_req.valid := state === s_meta_wait && needsWriteback(io.meta_resp.state)
io.wb_req.bits.ppn := io.meta_resp.tag
io.wb_req.bits.idx := idx_cnt
io.wb_req.bits.way_oh := UFixToOH(way_cnt, NWAYS)
@ -527,26 +522,23 @@ class MetaDataArray(lines: Int) extends Component {
val state_req = (new ioDecoupled) { new MetaArrayReq() }
}
val vd_array = Mem(lines, Bits(width = 2))
vd_array.setReadLatency(1);
val vd_wdata2 = Cat(io.state_req.bits.data.valid, io.state_req.bits.data.dirty)
vd_array.write(io.state_req.bits.idx, vd_wdata2, io.state_req.valid && io.state_req.bits.rw)
val vd_wdata1 = Cat(io.req.bits.data.valid, io.req.bits.data.dirty)
val vd_rdata1 = vd_array.rw(io.req.bits.idx, vd_wdata1, io.req.valid && io.req.bits.rw)
val permissions_array = Mem(lines, Bits(width = 2))
permissions_array.setReadLatency(1);
permissions_array.write(io.state_req.bits.idx, io.state_req.bits.data.state, io.state_req.valid && io.state_req.bits.rw)
val permissions_rdata1 = permissions_array.rw(io.req.bits.idx, io.req.bits.data.state, io.req.valid && io.req.bits.rw)
// don't allow reading and writing of vd_array in same cycle.
// this could be eliminated if the read port were combinational.
val vd_conflict = io.state_req.valid && (io.req.bits.idx === io.state_req.bits.idx)
val permissions_conflict = io.state_req.valid && (io.req.bits.idx === io.state_req.bits.idx)
val tag_array = Mem(lines, io.resp.tag)
tag_array.setReadLatency(1);
tag_array.setTarget('inst)
val tag_rdata = tag_array.rw(io.req.bits.idx, io.req.bits.data.tag, io.req.valid && io.req.bits.rw, cs = io.req.valid)
io.resp.valid := vd_rdata1(1).toBool
io.resp.dirty := vd_rdata1(0).toBool
io.resp.state := permissions_rdata1.toUFix
io.resp.tag := tag_rdata
io.req.ready := !vd_conflict
io.req.ready := !permissions_conflict
}
class MetaDataArrayArray(lines: Int) extends Component {
@ -692,7 +684,7 @@ class ioDCache(view: List[String] = null) extends Bundle(view) {
val resp_val = Bool(OUTPUT);
}
class HellaCache extends Component {
class HellaCache extends Component with ThreeStateIncoherence {
val io = new Bundle {
val cpu = new ioDmem()
val mem = new ioDCache().flip
@ -774,6 +766,7 @@ class HellaCache extends Component {
io.cpu.xcpt_ma_ld := r_cpu_req_val_ && r_req_read && misaligned
io.cpu.xcpt_ma_st := r_cpu_req_val_ && r_req_write && misaligned
// tags
val meta = new MetaDataArrayArray(lines)
val meta_arb = (new Arbiter(3)) { new MetaArrayArrayReq() }
@ -788,17 +781,16 @@ class HellaCache extends Component {
meta_arb.io.in(2).valid := io.cpu.req_val
meta_arb.io.in(2).bits.inner_req.idx := io.cpu.req_idx(indexmsb,indexlsb)
meta_arb.io.in(2).bits.inner_req.rw := Bool(false)
meta_arb.io.in(2).bits.inner_req.data.valid := Bool(false) // don't care
meta_arb.io.in(2).bits.inner_req.data.dirty := Bool(false) // don't care
meta_arb.io.in(2).bits.inner_req.data.tag := UFix(0) // don't care
meta_arb.io.in(2).bits.inner_req.data.state := UFix(0) // don't care
meta_arb.io.in(2).bits.inner_req.data.tag := UFix(0) // don't care
meta_arb.io.in(2).bits.way_en := ~UFix(0, NWAYS)
val early_tag_nack = !meta_arb.io.in(2).ready
val cpu_req_tag = Cat(io.cpu.req_ppn, r_cpu_req_idx)(tagmsb,taglsb)
val tag_match_arr = (0 until NWAYS).map( w => meta.io.resp(w).valid && (meta.io.resp(w).tag === cpu_req_tag))
val tag_match_arr = (0 until NWAYS).map( w => isHit(io.cpu.req_cmd, meta.io.resp(w).state) && (meta.io.resp(w).tag === cpu_req_tag))
val tag_match = Cat(Bits(0),tag_match_arr:_*).orR
val tag_hit = r_cpu_req_val && tag_match
val tag_miss = r_cpu_req_val && !tag_match
val hit_way_oh = Cat(Bits(0),tag_match_arr.reverse:_*) //TODO: use GenArray
val hit_way_oh = Cat(Bits(0),tag_match_arr.reverse:_*)(NWAYS-1, 0) //TODO: use GenArray
val meta_resp_way_oh = Mux(meta.io.way_en === ~UFix(0, NWAYS), hit_way_oh, meta.io.way_en)
val data_resp_way_oh = Mux(data.io.way_en === ~UFix(0, NWAYS), hit_way_oh, data.io.way_en)
val meta_resp_mux = Mux1H(NWAYS, meta_resp_way_oh, meta.io.resp)
@ -817,7 +809,7 @@ class HellaCache extends Component {
val replaced_way_id = replacer.io.way_id
val replaced_way_oh = UFixToOH(replaced_way_id, NWAYS)
val meta_wb_mux = meta.io.resp(replaced_way_id)
val dirty = meta_wb_mux.valid && meta_wb_mux.dirty
val needs_writeback = needsWriteback(meta_wb_mux.state)
// refill response
val block_during_refill = !io.mem.resp_val && (rr_count != UFix(0))
@ -857,20 +849,21 @@ class HellaCache extends Component {
// writeback
val wb_rdy = wb_arb.io.in(1).ready && !p_store_idx_match
wb_arb.io.in(1).valid := tag_miss && r_req_readwrite && dirty && !p_store_idx_match
wb_arb.io.in(1).valid := tag_miss && r_req_readwrite && needs_writeback && !p_store_idx_match
wb_arb.io.in(1).bits.ppn := meta_wb_mux.tag
wb_arb.io.in(1).bits.idx := r_cpu_req_idx(indexmsb,indexlsb)
wb_arb.io.in(1).bits.way_oh := replaced_way_oh
// tag update after a miss or a store to an exclusive clean line.
val clear_valid = tag_miss && r_req_readwrite && meta_wb_mux.valid && (!dirty || wb_rdy)
val set_dirty = tag_hit && !meta_resp_mux.dirty && r_req_write
val set_wb_state = tag_miss && r_req_readwrite && isValid(meta_wb_mux.state) && (!needs_writeback || wb_rdy)
//val set_hit_state = tag_hit && meta_resp_mux.state != newStateOnHit(r_cpu_req_cmd)
val new_hit_state = newStateOnHit(r_cpu_req_cmd, meta_resp_mux.state)
val set_hit_state = tag_hit && meta_resp_mux.state != new_hit_state
meta.io.state_req.bits.inner_req.rw := Bool(true)
meta.io.state_req.bits.inner_req.idx := r_cpu_req_idx(indexmsb,indexlsb)
meta.io.state_req.bits.inner_req.data.valid := tag_match
meta.io.state_req.bits.inner_req.data.dirty := tag_match
meta.io.state_req.valid := clear_valid || set_dirty
meta.io.state_req.bits.way_en := Mux(clear_valid, replaced_way_oh, hit_way_oh)
meta.io.state_req.bits.inner_req.data.state := Mux(set_wb_state, newStateOnWriteback(), new_hit_state)
meta.io.state_req.bits.way_en := Mux(set_wb_state, replaced_way_oh, hit_way_oh)
meta.io.state_req.valid := set_wb_state || set_hit_state
// pending store data, also used for AMO RHS
val amoalu = new AMOALU
@ -887,7 +880,7 @@ class HellaCache extends Component {
// miss handling
val mshr = new MSHRFile()
mshr.io.req_val := tag_miss && r_req_readwrite && (!dirty || wb_rdy) && (!r_req_write || replayer.io.sdq_enq.ready)
mshr.io.req_val := tag_miss && r_req_readwrite && (!needs_writeback || wb_rdy) && (!r_req_write || replayer.io.sdq_enq.ready)
mshr.io.req_ppn := cpu_req_tag
mshr.io.req_idx := r_cpu_req_idx(indexmsb,indexlsb)
mshr.io.req_tag := r_cpu_req_tag
@ -901,7 +894,7 @@ class HellaCache extends Component {
mshr.io.mem_req <> wb.io.refill_req
mshr.io.meta_req <> meta_arb.io.in(1)
mshr.io.replay <> replayer.io.replay
replayer.io.sdq_enq.valid := tag_miss && r_req_write && (!dirty || wb_rdy) && mshr.io.req_rdy
replayer.io.sdq_enq.valid := tag_miss && r_req_write && (!needs_writeback || wb_rdy) && mshr.io.req_rdy
replayer.io.sdq_enq.bits := cpu_req_data
data_arb.io.in(0).bits.inner_req.idx := mshr.io.mem_resp_idx
data_arb.io.in(0).bits.way_en := mshr.io.mem_resp_way_oh
@ -965,7 +958,7 @@ class HellaCache extends Component {
val pending_fence = Reg(resetVal = Bool(false))
pending_fence := (r_cpu_req_val && r_req_fence || pending_fence) && !flush_rdy
val nack_hit = p_store_match || r_req_write && !p_store_rdy
val nack_miss = dirty && !wb_rdy || !mshr.io.req_rdy || r_req_write && !replayer.io.sdq_enq.ready
val nack_miss = needs_writeback && !wb_rdy || !mshr.io.req_rdy || r_req_write && !replayer.io.sdq_enq.ready
val nack_flush = !flush_rdy && (r_req_fence || r_req_flush) ||
!flushed && r_req_flush
val nack = early_nack || r_req_readwrite && Mux(tag_match, nack_hit, nack_miss) || nack_flush