feat(OpenLLC): add support for ReadNoSnp transaction (OpenXiangShan/OpenLLC#22)

Author: sumailyyc

llc-src/src/main/scala/openLLC/MainPipe.scala

@@ -126,9 +126,10 @@ class MainPipe(implicit p: Parameters) extends LLCModule with HasCHIOpcodes {
   val cleanInvalid_s3       = !refill_task_s3 && opcode_s3 === CleanInvalid
   val cleanShared_s3        = !refill_task_s3 && opcode_s3 === CleanShared
   val writeCleanFull_s3     = !refill_task_s3 && opcode_s3 === WriteCleanFull
+  val readNoSnp_s3          = !refill_task_s3 && opcode_s3 === ReadNoSnp
 
   assert(!task_s3.valid || refill_task_s3 || readNotSharedDirty_s3 || readUnique_s3 || makeUnique_s3 || writeBackFull_s3 ||
-    evict_s3 || makeInvalid_s3 || cleanInvalid_s3 || cleanShared_s3 || writeCleanFull_s3, "Unsupported opcode")
+    evict_s3 || makeInvalid_s3 || cleanInvalid_s3 || cleanShared_s3 || writeCleanFull_s3 || readNoSnp_s3, "Unsupported opcode")
 
   /**
     * Requests have different coherence states after processing
@@ -257,6 +258,7 @@ class MainPipe(implicit p: Parameters) extends LLCModule with HasCHIOpcodes {
   val cleanInvalid_s4       = RegNext(cleanInvalid_s3, false.B)
   val cleanShared_s4        = RegNext(cleanShared_s3, false.B)
   val writeCleanFull_s4     = RegNext(writeCleanFull_s3, false.B)
+  val readNoSnp_s4          = RegNext(readNoSnp_s3, false.B)
   val sharedReq_s4          = RegNext(sharedReq_s3, false.B)
   val exclusiveReq_s4       = RegNext(exclusiveReq_s3, false.B)
   val releaseReq_s4         = RegNext(releaseReq_s3, false.B)
@@ -374,7 +376,7 @@ class MainPipe(implicit p: Parameters) extends LLCModule with HasCHIOpcodes {
   val respSC_s4 = sharedReq_s4
   val respUC_s4 = makeUnique_s4 || !makeUnique_s4 && exclusiveReq_s4 && (!selfDirty_s4 || !self_hit_s4)
   val respUD_s4 = !makeUnique_s4 && exclusiveReq_s4 && self_hit_s4 && selfDirty_s4
-  val respI_s4  = releaseReq_s4 || invalidReq_s4 || cleanReq_s4 || writeCleanFull_s4
+  val respI_s4  = releaseReq_s4 || invalidReq_s4 || cleanReq_s4 || writeCleanFull_s4 || readNoSnp_s4
   val snpVec_comp_s4 = VecInit(
     Mux(
       request_snoop_s4,
@@ -394,12 +396,12 @@ class MainPipe(implicit p: Parameters) extends LLCModule with HasCHIOpcodes {
   )
 
   comp_s4.valid := task_s4.valid && (
-    releaseReq_s4 || invalidReq_s4 || cleanReq_s4 || makeUnique_s4 || writeCleanFull_s4 ||
+    releaseReq_s4 || invalidReq_s4 || cleanReq_s4 || makeUnique_s4 || writeCleanFull_s4 || readNoSnp_s4 ||
     (readNotSharedDirty_s4 || readUnique_s4) && !self_hit_s4
   )
   comp_s4.bits.state.s_comp := false.B
   comp_s4.bits.state.s_urgentRead := true.B
-  comp_s4.bits.state.w_datRsp := !(readNotSharedDirty_s4 || readUnique_s4)
+  comp_s4.bits.state.w_datRsp := !(readNotSharedDirty_s4 || readUnique_s4 || readNoSnp_s4)
   comp_s4.bits.state.w_snpRsp := !Cat(snpVec_comp_s4).orR
   comp_s4.bits.state.w_compack := !(readUnique_s4 || readNotSharedDirty_s4 || makeUnique_s4)
   comp_s4.bits.state.w_comp := !(cleanInvalid_s4 && self_hit_s4 && selfDirty_s4)
@@ -420,7 +422,7 @@ class MainPipe(implicit p: Parameters) extends LLCModule with HasCHIOpcodes {
   mem_task_s4.expCompAck := false.B
 
   // need ReadNoSnp/WriteNoSnp downwards
-  val memRead_s4 = (readNotSharedDirty_s4 || readUnique_s4) && !self_hit_s4 && !peerRNs_hit_s4
+  val memRead_s4 = (readNotSharedDirty_s4 || readUnique_s4) && !self_hit_s4 && !peerRNs_hit_s4 || readNoSnp_s4
   val memWrite_s4 = cleanReq_s4 && unique_peerRN_s4 || writeCleanFull_s4
   mem_s4.valid := task_s4.valid && (memRead_s4 || memWrite_s4)
   mem_s4.bits.state.s_issueReq := false.B

llc-src/src/main/scala/openLLC/RequestArb.scala

@@ -67,8 +67,9 @@ class RequestArb(implicit p: Parameters) extends LLCModule with HasClientInfo wi
   val isCleanInvalid_s1 = !task_s1.bits.refillTask && task_s1.bits.chiOpcode === CleanInvalid
   val isCleanShared_s1 = !task_s1.bits.refillTask && task_s1.bits.chiOpcode === CleanShared
   val isWriteCleanFull_s1 = !task_s1.bits.refillTask && task_s1.bits.chiOpcode === WriteCleanFull
+  val isReadNoSnp_s1 = !task_s1.bits.refillTask && task_s1.bits.chiOpcode === ReadNoSnp
 
-  val isRead_s1  = isReadNotSharedDirty_s1 || isReadUnique_s1
+  val isRead_s1  = isReadNotSharedDirty_s1 || isReadUnique_s1 || isReadNoSnp_s1
   val isClean_s1 = isCleanInvalid_s1 || isCleanShared_s1 || isWriteCleanFull_s1
 
   // To prevent data hazards caused by read-after-write conflicts in the directory,

llc-src/src/main/scala/openLLC/ResponseUnit.scala

@@ -265,7 +265,8 @@ class ResponseUnit(implicit p: Parameters) extends LLCModule with HasCHIOpcodes
   }
 
   /* Issue */
-  val isRead = buffer.map(e => e.task.chiOpcode === ReadUnique || e.task.chiOpcode === ReadNotSharedDirty)
+  val isRead = buffer.map(e => e.task.chiOpcode === ReadUnique || e.task.chiOpcode === ReadNotSharedDirty ||
+    e.task.chiOpcode === ReadNoSnp)
   txdatArb.io.in.zip(buffer).zip(isRead).foreach { case ((in, e), r) =>
     in.valid := e.valid && e.state.w_datRsp && e.state.w_snpRsp && e.state.s_urgentRead && !e.state.s_comp && r
     in.bits.task := e.task