yystopf
/
riscv-lab
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

fix(dcache): 修复显著的问题，目前仍存在bug

This commit is contained in:
Liphen 2023-12-25 14:02:01 +08:00
parent e1639e6f8b
commit 90bc47c48b
2 changed files with 137 additions and 104 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

218
chisel/playground/src/cache/DCache.scala vendored
View File

@ -51,12 +51,18 @@ class WriteBufferUnit extends Bundle {
}
class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Module {
val nway: Int = cacheConfig.nway
val nindex: Int = cacheConfig.nindex
val nbank: Int = cacheConfig.nbank
val tagWidth: Int = cacheConfig.tagWidth
val burstSize: Int = 16
val writeFifoDepth: Int = 4
val nway = cacheConfig.nway
val nindex = cacheConfig.nindex
val nbank = cacheConfig.nbank
val instFetchNum = config.instFetchNum
val bankOffsetWidth = cacheConfig.bankOffsetWidth
val bankIndexWidth = cacheConfig.offsetWidth - bankOffsetWidth
val bytesPerBank = cacheConfig.bytesPerBank
val tagWidth = cacheConfig.tagWidth
val indexWidth = cacheConfig.indexWidth
val offsetWidth = cacheConfig.offsetWidth
val bitsPerBank = cacheConfig.bitsPerBank
val writeFifoDepth = 4
// 每个bank中存AXI_DATA_WID位的数据
// TODO:目前的实现只保证了AXI_DATA_WID为XLEN的情况下的正确性
@ -71,6 +77,20 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val s_idle :: s_uncached :: s_writeback :: s_replace :: s_save :: Nil = Enum(5)
val state = RegInit(s_idle)
// ==========================================================
// | tag | index | offset |
// | | | bank index | bank offset |
// ==========================================================
val index = io.cpu.addr(indexWidth + offsetWidth - 1, offsetWidth)
val bank_addr = io.cpu.addr(indexWidth + offsetWidth - 1, log2Ceil(XLEN / 8)) // TODO：目前临时使用一下
val bank_index = io.cpu.addr(bankIndexWidth + bankOffsetWidth - 1, bankOffsetWidth)
val bank_offset =
if (bankOffsetWidth > log2Ceil(XLEN / 8))
io.cpu.addr(bankOffsetWidth - 1, log2Ceil(XLEN / 8)) // 保证地址对齐
else
0.U
val tlb_fill = RegInit(false.B)
io.cpu.tlb.fill := tlb_fill
@ -92,9 +112,9 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
writeFifo.io.enq.bits := 0.U.asTypeOf(new WriteBufferUnit())
writeFifo.io.deq.ready := false.B
val axi_cnt = Counter(burstSize)
val read_ready_cnt = RegInit(0.U(4.W))
val read_ready_set = RegInit(0.U(6.W))
val axi_cnt = Counter(cached_len + 1)
val read_ready_cnt = RegInit(0.U(4.W))
val read_ready_index = RegInit(0.U(6.W))
// * victim cache * //
val victim = RegInit(0.U.asTypeOf(new Bundle {
@ -105,10 +125,10 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val working = Bool()
val writeback = Bool()
}))
val victim_cnt = Counter(burstSize)
val victim_cnt = Counter(cached_len + 1)
val victim_addr = Cat(victim.index, victim_cnt.value)
val fset = io.cpu.addr(11, 6)
val fence_index = index
val fence = RegInit(0.U.asTypeOf(new Bundle {
val working = Bool()
}))
@ -117,12 +137,15 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val ar_handshake = RegInit(false.B)
val aw_handshake = RegInit(false.B)
val data_raddr = Mux(victim.valid, victim_addr, io.cpu.addr(11, 2))
val data_wstrb = Wire(Vec(nway, UInt(AXI_STRB_WID.W)))
val data_waddr = Mux(victim.valid, victim.waddr, io.cpu.addr(11, 2))
val data_wdata = Mux(state === s_replace, io.axi.r.bits.data, io.cpu.wdata)
//
val data_raddr = Mux(victim.valid, victim_addr, bank_addr)
val replace_wstrb = Wire(Vec(nway, UInt(AXI_STRB_WID.W)))
val replace_waddr = Mux(victim.valid, victim.waddr, bank_addr)
val replace_wdata = Mux(state === s_replace, io.axi.r.bits.data, io.cpu.wdata)
val tag_raddr = Mux(victim.valid, victim.index, io.cpu.addr(11, 6))
val replace_way = lru(index)
val tag_raddr = Mux(victim.valid, victim.index, index)
val tag_wstrb = RegInit(VecInit(Seq.fill(nway)(false.B)))
val tag_wdata = RegInit(0.U(tagWidth.W))
@ -136,10 +159,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val mmio_write_stall = io.cpu.tlb.uncached && io.cpu.wen.orR && !writeFifo.io.enq.ready
val cached_stall = !io.cpu.tlb.uncached && !cache_hit
val sel = tag_compare_valid(1)
// * physical index * //
val physical_index = io.cpu.addr(11, 6)
val select_way = tag_compare_valid(1)
val dcache_stall = Mux(
state === s_idle && !tlb_fill,
@ -151,12 +171,12 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val saved_rdata = RegInit(0.U(XLEN.W))
// forward last stored data in data bram
val last_waddr = RegNext(data_waddr)
val last_waddr = RegNext(replace_waddr)
val last_wstrb = RegInit(VecInit(Seq.fill(nway)(0.U(XLEN.W))))
val last_wdata = RegNext(data_wdata)
val last_wdata = RegNext(replace_wdata)
val cache_data_forward = Wire(Vec(nway, UInt(XLEN.W)))
io.cpu.rdata := Mux(state === s_save, saved_rdata, cache_data_forward(sel))
io.cpu.rdata := Mux(state === s_save, saved_rdata, cache_data_forward(select_way))
// bank tagv ram
for { i <- 0 until nway } {
@ -165,10 +185,10 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
bank.io.raddr := data_raddr
data(i) := bank.io.rdata
bank.io.wen := data_wstrb(i).orR
bank.io.waddr := data_waddr
bank.io.wdata := data_wdata
bank.io.wstrb := data_wstrb(i)
bank.io.wen := replace_wstrb(i).orR
bank.io.waddr := replace_waddr
bank.io.wdata := replace_wdata
bank.io.wstrb := replace_wstrb(i)
val tagRam = Module(new LUTRam(nindex, tagWidth))
tagRam.io.raddr := tag_raddr
@ -178,22 +198,22 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
tagRam.io.waddr := victim.index
tagRam.io.wdata := tag_wdata
tag_compare_valid(i) := tag(i) === io.cpu.tlb.tag && valid(physical_index)(i) && io.cpu.tlb.translation_ok
tag_compare_valid(i) := tag(i) === io.cpu.tlb.tag && valid(index)(i) && io.cpu.tlb.translation_ok
cache_data_forward(i) := Mux(
last_waddr === io.cpu.addr(11, 2),
last_waddr === bank_addr,
((last_wstrb(i) & last_wdata) | (data(i) & (~last_wstrb(i)))),
data(i)
)
data_wstrb(i) := Mux(
replace_wstrb(i) := Mux(
tag_compare_valid(i) && io.cpu.en && io.cpu.wen.orR && !io.cpu.tlb.uncached && state === s_idle && !tlb_fill,
io.cpu.wstrb,
victim.wstrb(i)
)
last_wstrb(i) := Cat((AXI_STRB_WID - 1 to 0 by -1).map(j => Fill(8, data_wstrb(i)(j))))
last_wstrb(i) := Cat((AXI_STRB_WID - 1 to 0 by -1).map(j => Fill(8, replace_wstrb(i)(j))))
}
val write_buffer_axi_busy = RegInit(false.B)
val writeFifo_axi_busy = RegInit(false.B)
val ar = RegInit(0.U.asTypeOf(new AR()))
val arvalid = RegInit(false.B)
@ -222,7 +242,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val current_mmio_write_saved = RegInit(false.B)
// write buffer
when(write_buffer_axi_busy) { // To implement SC memory ordering, when store buffer busy, axi is unseable.
when(writeFifo_axi_busy) { // To implement SC memory ordering, when store buffer busy, axi is unseable.
when(io.axi.aw.fire) {
awvalid := false.B
}
@ -231,7 +251,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
w.last := false.B
}
when(io.axi.b.fire) {
write_buffer_axi_busy := false.B
writeFifo_axi_busy := false.B
}
}.elsewhen(writeFifo.io.deq.valid) {
writeFifo.io.deq.ready := writeFifo.io.deq.valid
@ -241,11 +261,11 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
w.data := writeFifo.io.deq.bits.data
w.strb := writeFifo.io.deq.bits.strb
}
aw.len := 0.U
awvalid := true.B
w.last := true.B
wvalid := true.B
write_buffer_axi_busy := true.B
aw.len := 0.U
awvalid := true.B
w.last := true.B
wvalid := true.B
writeFifo_axi_busy := true.B
}
switch(state) {
@ -282,7 +302,7 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
when(io.cpu.dcache_ready && io.cpu.cpu_ready) {
current_mmio_write_saved := false.B
}
}.elsewhen(!(writeFifo.io.deq.valid || write_buffer_axi_busy)) {
}.elsewhen(!(writeFifo.io.deq.valid || writeFifo_axi_busy)) {
ar.addr := Mux(io.cpu.rlen === 2.U, Cat(io.cpu.tlb.pa(31, 2), 0.U(2.W)), io.cpu.tlb.pa)
ar.len := 0.U
ar.size := io.cpu.rlen
@ -294,42 +314,42 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
when(!cache_hit) {
state := s_replace
axi_cnt.reset()
victim.index := physical_index
victim.index := index
victim_cnt.reset()
read_ready_set := physical_index
read_ready_index := index
read_ready_cnt := 0.U
victim.waddr := Cat(physical_index, 0.U(4.W))
victim.waddr := Cat(index, 0.U((offsetWidth - log2Ceil(XLEN / 8)).W))
victim.valid := true.B
victim.writeback := dirty(physical_index)(lru(physical_index))
victim.writeback := dirty(index)(replace_way)
}.otherwise {
when(io.cpu.dcache_ready) {
// update lru and mark dirty
lru(physical_index) := ~sel
replace_way := ~select_way
when(io.cpu.wen.orR) {
dirty(physical_index)(sel) := true.B
dirty(index)(select_way) := true.B
}
when(!io.cpu.cpu_ready) {
saved_rdata := cache_data_forward(sel)
saved_rdata := cache_data_forward(select_way)
state := s_save
}
}
}
}
}.elsewhen(io.cpu.fence) {
when(dirty(fset).contains(true.B)) {
when(!(writeFifo.io.deq.valid || write_buffer_axi_busy)) {
when(dirty(fence_index).contains(true.B)) {
when(!(writeFifo.io.deq.valid || writeFifo_axi_busy)) {
state := s_writeback
axi_cnt.reset()
victim.index := fset
victim.index := fence_index
victim_cnt.reset()
read_ready_set := fset
read_ready_cnt := 0.U
victim.valid := true.B
read_ready_index := fence_index
read_ready_cnt := 0.U
victim.valid := true.B
}
}.otherwise {
when(valid(fset).contains(true.B)) {
valid(fset)(0) := false.B
valid(fset)(1) := false.B
when(valid(fence_index).contains(true.B)) {
valid(fence_index)(0) := false.B
valid(fence_index)(1) := false.B
}
state := s_save
}
@ -347,18 +367,18 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}
is(s_writeback) {
when(fence.working) {
when(victim_cnt.value =/= (burstSize - 1).U) {
when(victim_cnt.value =/= (cached_len).U) {
victim_cnt.inc()
}
read_ready_set := victim.index
read_ready_index := victim.index
read_ready_cnt := victim_cnt.value
read_buffer(read_ready_cnt) := data(dirty(fset)(1))
read_buffer(read_ready_cnt) := data(dirty(fence_index)(1))
when(!aw_handshake) {
aw.addr := Cat(tag(dirty(fset)(1)), fset, 0.U(6.W))
aw.addr := Cat(tag(dirty(fence_index)(1)), fence_index, 0.U(6.W))
aw.len := cached_len.U
aw.size := cached_size.U
awvalid := true.B
w.data := data(dirty(fset)(1))
w.data := data(dirty(fence_index)(1))
w.strb := ~0.U(AXI_STRB_WID.W)
w.last := false.B
wvalid := true.B
@ -373,21 +393,21 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}.otherwise {
w.data := Mux(
((axi_cnt.value + 1.U) === read_ready_cnt),
data(dirty(fset)(1)),
data(dirty(fence_index)(1)),
read_buffer(axi_cnt.value + 1.U)
)
axi_cnt.inc()
when(axi_cnt.value + 1.U === (burstSize - 1).U) {
when(axi_cnt.value + 1.U === (cached_len).U) {
w.last := true.B
}
}
}
when(io.axi.b.valid) {
dirty(fset)(dirty(fset)(1)) := false.B
fence.working := false.B
victim.valid := false.B
acc_err := io.axi.b.bits.resp =/= RESP_OKEY.U
state := s_idle
dirty(fence_index)(dirty(fence_index)(1)) := false.B
fence.working := false.B
victim.valid := false.B
acc_err := io.axi.b.bits.resp =/= RESP_OKEY.U
state := s_idle
}
}.otherwise {
aw_handshake := false.B
@ -396,22 +416,22 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}
}
is(s_replace) {
when(!(writeFifo.io.deq.valid || write_buffer_axi_busy)) {
when(!(writeFifo.io.deq.valid || writeFifo_axi_busy)) {
when(victim.working) {
when(victim.writeback) {
when(victim_cnt.value =/= (burstSize - 1).U) {
when(victim_cnt.value =/= (cached_len).U) {
victim_cnt.inc()
}
read_ready_set := victim.index
read_ready_index := victim.index
read_ready_cnt := victim_cnt.value
read_buffer(read_ready_cnt) := data(lru(physical_index))
read_buffer(read_ready_cnt) := data(replace_way)
when(!aw_handshake) {
aw.addr := Cat(tag(lru(physical_index)), physical_index, 0.U(6.W))
aw.addr := Cat(tag(replace_way), index, 0.U(offsetWidth.W))
aw.len := cached_len.U
aw.size := cached_size.U
awvalid := true.B
aw_handshake := true.B
w.data := data(lru(physical_index))
w.data := data(replace_way)
w.strb := ~0.U(AXI_STRB_WID.W)
w.last := false.B
wvalid := true.B
@ -425,39 +445,39 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}.otherwise {
w.data := Mux(
((axi_cnt.value + 1.U) === read_ready_cnt),
data(lru(physical_index)),
data(replace_way),
read_buffer(axi_cnt.value + 1.U)
)
axi_cnt.inc()
when(axi_cnt.value + 1.U === (burstSize - 1).U) {
when(axi_cnt.value + 1.U === (cached_len).U) {
w.last := true.B
}
}
}
when(io.axi.b.valid) {
dirty(physical_index)(lru(physical_index)) := false.B
victim.writeback := false.B
dirty(index)(replace_way) := false.B
victim.writeback := false.B
}
}
when(!ar_handshake) {
ar.addr := Cat(io.cpu.tlb.pa(31, 6), 0.U(6.W))
ar.len := cached_len.U
ar.size := cached_size.U // 8 字节
arvalid := true.B
rready := true.B
ar_handshake := true.B
victim.wstrb(lru(physical_index)) := ~0.U(AXI_STRB_WID.W)
tag_wstrb(lru(physical_index)) := true.B
tag_wdata := io.cpu.tlb.pa(31, 12)
ar.addr := Cat(io.cpu.tlb.pa(PADDR_WID - 1, offsetWidth), 0.U(offsetWidth.W))
ar.len := cached_len.U
ar.size := cached_size.U // 8 字节
arvalid := true.B
rready := true.B
ar_handshake := true.B
victim.wstrb(replace_way) := ~0.U(AXI_STRB_WID.W)
tag_wstrb(replace_way) := true.B
tag_wdata := io.cpu.tlb.tag
}
when(io.axi.ar.fire) {
tag_wstrb(lru(physical_index)) := false.B
arvalid := false.B
tag_wstrb(replace_way) := false.B
arvalid := false.B
}
when(io.axi.r.fire) {
when(io.axi.r.bits.last) {
rready := false.B
victim.wstrb(lru(physical_index)) := 0.U
rready := false.B
victim.wstrb(replace_way) := 0.U
}.otherwise {
victim.waddr := victim.waddr + 1.U
}
@ -465,8 +485,8 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
when(
(!victim.writeback || io.axi.b.valid) && ((ar_handshake && io.axi.r.valid && io.axi.r.bits.last) || (ar_handshake && !rready))
) {
victim.valid := false.B
valid(physical_index)(lru(physical_index)) := true.B
victim.valid := false.B
valid(index)(replace_way) := true.B
}
when(!victim.valid) {
victim.working := false.B
@ -486,4 +506,16 @@ class DCache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}
}
}
println("----------------------------------------")
println("DCache: ")
println("nindex: " + nindex)
println("nbank: " + nbank)
println("bitsPerBank: " + bitsPerBank)
println("bankOffsetWidth: " + bankOffsetWidth)
println("bankIndexWidth: " + bankIndexWidth)
println("tagWidth: " + tagWidth)
println("indexWidth: " + indexWidth)
println("offsetWidth: " + offsetWidth)
println("----------------------------------------")
}

23
chisel/playground/src/cache/ICache.scala vendored
View File

@ -73,7 +73,7 @@ class ICache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
val instBlocksPerBank = bitsPerBank / AXI_DATA_WID
val bank_index = io.cpu.addr(0)(offsetWidth - 1, bankOffsetWidth)
val bank_offset = io.cpu.addr(0)(bankOffsetWidth - 1, 2) // PC低2位必定是0
val bank_offset = io.cpu.addr(0)(bankOffsetWidth - 1, log2Ceil(INST_WID / 8)) // PC低2位必定是0
val tlb_fill = RegInit(false.B)
// * fsm * //
@ -97,8 +97,7 @@ class ICache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
// * itlb * //
when(tlb_fill) { tlb_fill := false.B }
io.cpu.tlb.fill := tlb_fill
io.cpu.tlb.icache_is_save := (state === s_save)
io.cpu.tlb.fill := tlb_fill
// * fence * //
// fence指令时清空cache，等同于将所有valid位置0
@ -309,12 +308,14 @@ class ICache(cacheConfig: CacheConfig)(implicit config: CpuConfig) extends Modul
}
}
// println("ICache: ")
// println("nindex: " + nindex)
// println("nbank: " + nbank)
// println("bankOffsetWidth: " + bankOffsetWidth)
// println("bytesPerBank: " + bytesPerBank)
// println("tagWidth: " + tagWidth)
// println("indexWidth: " + indexWidth)
// println("offsetWidth: " + offsetWidth)
println("----------------------------------------")
println("ICache: ")
println("nindex: " + nindex)
println("nbank: " + nbank)
println("bankOffsetWidth: " + bankOffsetWidth)
println("bytesPerBank: " + bytesPerBank)
println("tagWidth: " + tagWidth)
println("indexWidth: " + indexWidth)
println("offsetWidth: " + offsetWidth)
println("----------------------------------------")
}