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VexRiscv
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This commit is contained in:
Dolu1990 2018-09-28 16:02:33 +02:00
parent 32cf90a162
commit 37a1970ad6
2 changed files with 106 additions and 36 deletions
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1
src/main/scala/vexriscv/Riscv.scala
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@ -99,6 +99,7 @@ object Riscv{
def ECALL = M"00000000000000000000000001110011"
def EBREAK = M"00000000000100000000000001110011"
def MRET = M"00110000001000000000000001110011"
def SRET = M"00010000001000000000000001110011"
def WFI = M"00010000010100000000000001110011"
def FENCE = M"-----------------000-----0001111"

145
src/main/scala/vexriscv/plugin/CsrPlugin.scala
View File

@ -205,13 +205,13 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
var pluginExceptionPort : Flow[ExceptionCause] = null
var timerInterrupt, externalInterrupt : Bool = null
var timerInterruptS, externalInterruptS : Bool = null
var privilege : Bits = null
var privilege : UInt = null
var selfException : Flow[ExceptionCause] = null
var contextSwitching : Bool = null
override def isContextSwitching = contextSwitching
object EnvCtrlEnum extends SpinalEnum(binarySequential){
val NONE, EBREAK, MRET= newElement()
val NONE, EBREAK, XRET = newElement()
val WFI = if(wfiGen) newElement() else null
val ECALL = if(ecallGen) newElement() else null
}
@ -263,8 +263,8 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
CSRRWI -> immediatActions,
CSRRSI -> immediatActions,
CSRRCI -> immediatActions,
// EBREAK -> (defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.EBREAK)), //TODO
MRET -> (defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.MRET))
MRET -> (defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.XRET)),
SRET -> (defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.XRET))
))
if(wfiGen) decoderService.add(WFI, defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.WFI))
if(ecallGen) decoderService.add(ECALL, defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.ECALL))
@ -284,7 +284,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
externalInterrupt = in Bool() setName("externalInterrupt")
contextSwitching = Bool().setName("contextSwitching")
privilege = RegInit(B"11")
privilege = RegInit(U"11")
if(catchIllegalAccess)
selfException = newExceptionPort(pipeline.execute)
@ -328,7 +328,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
val mepc = Reg(UInt(xlen bits))
val mstatus = new Area{
val MIE, MPIE = RegInit(False)
val MPP = RegInit(B"11")
val MPP = RegInit(U"11")
}
val mip = new Area{
val MEIP = RegNext(externalInterrupt) init(False)
@ -354,7 +354,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
val sstatus = new Area{
val SIE, SPIE = RegInit(False)
val SPP = RegInit(B"1")
val SPP = RegInit(U"1")
}
val sip = new Area{
@ -429,6 +429,50 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
minstret := minstret + 1
}
case class InterruptSource(cond : Bool, id : Int)
case class InterruptModel(privilege : Int, privilegeCond : Bool, sources : ArrayBuffer[InterruptSource])
val interruptModel = ArrayBuffer[InterruptModel]()
interruptModel += InterruptModel(1, sstatus.SIE && privilege <= "01", ArrayBuffer(
InterruptSource(sip.STIP && sie.STIE, 5),
InterruptSource(sip.SSIP && sie.SSIE, 1),
InterruptSource(sip.SEIP && sie.SEIE, 9)
))
interruptModel += InterruptModel(3, mstatus.MIE , ArrayBuffer(
InterruptSource(mip.MTIP && mie.MTIE, 7),
InterruptSource(mip.MSIP && mie.MSIE, 3),
InterruptSource(mip.MEIP && mie.MEIE, 11)
))
case class DelegatorModel(value : Bits, source : Int, target : Int)
def solveDelegators(delegators : Seq[DelegatorModel], id : Int, upTo : Int): UInt = {
val filtredDelegators = delegators.filter(_.target <= upTo)
val ret = U(filtredDelegators.last.target, 2 bits)
for(d <- filtredDelegators){
when(!d.value(id)){
ret := d.source
}
}
ret
}
def solveDelegators(delegators : Seq[DelegatorModel], id : UInt, upTo : UInt): UInt = {
val ret = U(delegators.last.target, 2 bits)
for(d <- delegators){
when(!d.value(id) || d.target > upTo){
ret := d.source
}
}
ret
}
val interruptDelegators = ArrayBuffer[DelegatorModel]()
interruptDelegators += DelegatorModel(mideleg,0, 2)
val exceptionDelegators = ArrayBuffer[DelegatorModel]()
exceptionDelegators += DelegatorModel(medeleg,0, 2)
val mepcCaptureStage = if(exceptionPortsInfos.nonEmpty) writeBack else decode
@ -438,6 +482,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
val exceptionValids = Vec(stages.map(s => Bool().setPartialName(s.getName())))
val exceptionValidsRegs = Vec(stages.map(s => Reg(Bool).init(False).setPartialName(s.getName()))).allowUnsetRegToAvoidLatch
val exceptionContext = Reg(ExceptionCause())
val exceptionTargetPrivilege = solveDelegators(exceptionDelegators, exceptionContext.code, privilege)
val groupedByStage = exceptionPortsInfos.map(_.stage).distinct.map(s => {
val stagePortsInfos = exceptionPortsInfos.filter(_.stage == s).sortWith(_.priority > _.priority)
@ -490,32 +535,33 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
val interruptRequest = ((mip.MSIP && mie.MSIE) || (mip.MEIP && mie.MEIE) || (mip.MTIP && mie.MTIE)) && mstatus.MIE
val interrupt = interruptRequest && allowInterrupts
val interrupt = False
val interruptCode = UInt(4 bits).assignDontCare().addTag(Verilator.public)
val interruptTargetPrivilege = UInt(2 bits).assignDontCare()
for(model <- interruptModel){
when(model.privilegeCond){
when(model.sources.map(_.cond).orR){
interrupt := True
}
for(source <- model.sources){
when(source.cond){
interruptCode := source.id
interruptTargetPrivilege := solveDelegators(interruptDelegators, source.id, model.privilege)
}
}
}
}
interrupt.clearWhen(!allowInterrupts)
val exception = if(exceptionPortCtrl != null) exceptionPortCtrl.exceptionValids.last && allowException else False
val writeBackWasWfi = if(wfiGen) RegNext(writeBack.arbitration.isFiring && writeBack.input(ENV_CTRL) === EnvCtrlEnum.WFI) init(False) else False
val deteriministicLogic = if(deterministicInteruptionEntry) new Area{
val counter = Reg(UInt(4 bits)) init(0)
when(!interruptRequest || !mstatus.MIE){
counter := 0
} otherwise {
when(counter < 6){
when(writeBack.arbitration.isFiring){
counter := counter + 1
}
}
val counterPlusPending = counter + CountOne(stages.tail.map(_.arbitration.isValid))
when(counterPlusPending < 6){
inhibateInterrupts()
}
}
}
//Used to make the pipeline empty softly (for interrupts)
val pipelineLiberator = new Area{
when(interrupt && decode.arbitration.isValid){
@ -527,37 +573,60 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
}
//Interrupt/Exception entry logic
val interruptCode = ((mip.MEIP && mie.MEIE) ? U(11) | ((mip.MSIP && mie.MSIE) ? U(3) | U(7))).addTag(Verilator.public)
val interruptJump = Bool.addTag(Verilator.public)
interruptJump := interrupt && pipelineLiberator.done
when(exception || interruptJump){
val hadException = RegNext(exception) init(False)
writeBack.arbitration.haltItself setWhen(exception)
val targetPrivilege = CombInit(interruptTargetPrivilege)
if(exceptionPortCtrl != null) when(hadException) {
targetPrivilege := exceptionPortCtrl.exceptionTargetPrivilege
}
when(hadException || (interruptJump && !exception)){
jumpInterface.valid := True
jumpInterface.payload := mtvec
memory.arbitration.flushAll := True
if(exceptionPortCtrl != null) exceptionPortCtrl.exceptionValidsRegs.last := False
switch(targetPrivilege){
is(1){
sstatus.SIE := False
sstatus.SPIE := sstatus.SIE
sstatus.SPP := privilege
if(exceptionPortCtrl != null) {
stval := exceptionPortCtrl.exceptionContext.badAddr
scause.exceptionCode := exceptionPortCtrl.exceptionContext.code
}
}
is(3){
mstatus.MIE := False
mstatus.MPIE := mstatus.MIE
mstatus.MPP := privilege
if(exceptionPortCtrl != null) {
mtval := exceptionPortCtrl.exceptionContext.badAddr
mcause.exceptionCode := exceptionPortCtrl.exceptionContext.code
}
}
}
mepc := mepcCaptureStage.input(PC)
mcause.interrupt := interruptJump
mcause.exceptionCode := interruptCode
}
when(RegNext(exception)){
mtval := (if(exceptionPortCtrl != null) exceptionPortCtrl.exceptionContext.badAddr else U(0))
mcause.exceptionCode := (if(exceptionPortCtrl != null) exceptionPortCtrl.exceptionContext.code else U(0))
}
//Manage MRET instructions
when(execute.arbitration.isValid && execute.input(ENV_CTRL) === EnvCtrlEnum.MRET) {
//Manage MRET / SRET instructions
when(execute.arbitration.isValid && execute.input(ENV_CTRL) === EnvCtrlEnum.XRET) {
when(memory.arbitration.isValid || writeBack.arbitration.isValid){
execute.arbitration.haltItself := True
} otherwise {
jumpInterface.valid := True
jumpInterface.payload := mepc
decode.arbitration.flushAll := True
//TODO
mstatus.MIE := mstatus.MPIE
privilege := mstatus.MPP
}
@ -663,7 +732,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
}
}
}
illegalAccess setWhen(privilege.asUInt < csrAddress(9 downto 8).asUInt)
illegalAccess setWhen(privilege < csrAddress(9 downto 8).asUInt)
})
}
}