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rocket-chip/src/main/scala/rocketchip/DebugTransport.scala
2017-04-20 10:19:50 -07:00

253 lines
8.1 KiB
Scala

// See LICENSE.SiFive for license details.
package rocketchip
import Chisel._
import util._
import config._
import jtag._
import uncore.devices.{DMIConsts, DMIIO, DMIReq, DMIResp}
case object IncludeJtagDTM extends Field[Boolean]
case class JtagDTMConfig (
idcodeVersion : Int, // chosen by manuf.
idcodePartNum : Int, // Chosen by manuf.
idcodeManufId : Int, // Assigned by JEDEC
debugIdleCycles : Int)
case object JtagDTMKey extends Field[JtagDTMConfig]
class JtagDTMKeyDefault extends JtagDTMConfig(
idcodeVersion = 0,
idcodePartNum = 0,
idcodeManufId = 0,
debugIdleCycles = 5) // Reasonable guess for synchronization.
object dtmJTAGAddrs {
def IDCODE = 0x1
def DTM_INFO = 0x10
def DMI_ACCESS = 0x11
}
class DMIAccessUpdate(addrBits: Int) extends Bundle {
val addr = UInt(width = addrBits)
val data = UInt(width = DMIConsts.dmiDataSize)
val op = UInt(width = DMIConsts.dmiOpSize)
override def cloneType = new DMIAccessUpdate(addrBits).asInstanceOf[this.type]
}
class DMIAccessCapture(addrBits: Int) extends Bundle {
val addr = UInt(width = addrBits)
val data = UInt(width = DMIConsts.dmiDataSize)
val resp = UInt(width = DMIConsts.dmiRespSize)
override def cloneType = new DMIAccessCapture(addrBits).asInstanceOf[this.type]
}
class DTMInfo extends Bundle {
val reserved1 = UInt(15.W)
val dmireset = Bool()
val reserved0 = UInt(1.W)
val dmiIdleCycles = UInt(3.W)
val dmiStatus = UInt(2.W)
val debugAddrBits = UInt(6.W)
val debugVersion = UInt(4.W)
}
class DebugTransportModuleJTAG(debugAddrBits: Int, c: JtagDTMConfig)
(implicit val p: Parameters) extends Module {
val io = new Bundle {
val dmi = new DMIIO()(p)
val jtag = Flipped(new JTAGIO(hasTRSTn = false))
val jtag_reset = Bool(INPUT)
val jtag_mfr_id = UInt(INPUT, 11)
val fsmReset = Bool(OUTPUT)
}
//--------------------------------------------------------
// Reg and Wire Declarations
val dtmInfo = Wire(new DTMInfo)
val busyReg = RegInit(Bool(false))
val stickyBusyReg = RegInit(Bool(false))
val stickyNonzeroRespReg = RegInit(Bool(false))
val skipOpReg = Reg(init = Bool(false)) // Skip op because we're busy
val downgradeOpReg = Reg(init = Bool(false)) // downgrade op because prev. failed.
val busy = Wire(Bool())
val nonzeroResp = Wire(Bool())
val busyResp = Wire(new DMIAccessCapture(debugAddrBits))
val nonbusyResp = Wire(new DMIAccessCapture(debugAddrBits))
val dmiResp = Wire(new DMIAccessCapture(debugAddrBits))
val nopResp = Wire(new DMIAccessCapture(debugAddrBits))
val dmiReqReg = Reg(new DMIReq(debugAddrBits))
val dmiReqValidReg = Reg(init = Bool(false));
val dmiStatus = Wire(UInt(width = 2))
//--------------------------------------------------------
// DTM Info Chain Declaration
dmiStatus := Cat(stickyNonzeroRespReg, stickyNonzeroRespReg | stickyBusyReg)
dtmInfo.debugVersion := 1.U // This implements version 1 of the spec.
dtmInfo.debugAddrBits := UInt(debugAddrBits)
dtmInfo.dmiStatus := dmiStatus
dtmInfo.dmiIdleCycles := UInt(c.debugIdleCycles)
dtmInfo.reserved0 := 0.U
dtmInfo.dmireset := false.B // This is write-only
dtmInfo.reserved1 := 0.U
val dtmInfoChain = Module (CaptureUpdateChain(gen = new DTMInfo()))
dtmInfoChain.io.capture.bits := dtmInfo
//--------------------------------------------------------
// Debug Access Chain Declaration
val dmiAccessChain = Module(CaptureUpdateChain(genCapture = new DMIAccessCapture(debugAddrBits),
genUpdate = new DMIAccessUpdate(debugAddrBits)))
//--------------------------------------------------------
// Debug Access Support
// Busy Register. We become busy when we first try to send a request.
// We stop being busy when we accept a response.
when (io.dmi.req.valid) {
busyReg := Bool(true)
}
when (io.dmi.resp.fire()) {
busyReg := Bool(false)
}
// We are busy during a given CAPTURE
// if we haven't received a valid response yet or if we
// were busy last time without a reset.
// busyReg will still be set when we check it,
// so the logic for checking busy looks ahead.
busy := (busyReg & !io.dmi.resp.valid) | stickyBusyReg;
// Downgrade/Skip. We make the decision to downgrade or skip
// during every CAPTURE_DR, and use the result in UPDATE_DR.
// The sticky versions are reset by write to dmiReset in DTM_INFO.
when (dmiAccessChain.io.update.valid) {
skipOpReg := Bool(false)
downgradeOpReg := Bool(false)
}
when (dmiAccessChain.io.capture.capture) {
skipOpReg := busy
downgradeOpReg := (!busy & nonzeroResp)
stickyBusyReg := busy
stickyNonzeroRespReg := nonzeroResp
}
when (dtmInfoChain.io.update.valid) {
when (dtmInfoChain.io.update.bits.dmireset) {
stickyNonzeroRespReg := Bool(false)
stickyBusyReg := Bool(false)
}
}
// Especially for the first request, we must consider dtmResp.valid,
// so that we don't consider junk in the FIFO to be an error response.
// The current specification says that any non-zero response is an error.
// But there is actually no case in the current design where you SHOULD get an error,
// as we haven't implemented Bus Masters or Serial Ports, which are the only cases errors
// can occur.
nonzeroResp := stickyNonzeroRespReg | (io.dmi.resp.valid & (io.dmi.resp.bits.resp != UInt(0)))
assert(!nonzeroResp, "There is no reason to get a non zero response in the current system.");
assert(!stickyNonzeroRespReg, "There is no reason to have a sticky non zero response in the current system.");
busyResp.addr := UInt(0)
busyResp.resp := Fill(DMIConsts.dmiRespSize, 1.U) // Generalizing busy to 'all-F'
busyResp.data := UInt(0)
dmiResp.addr := dmiReqReg.addr
dmiResp.resp := io.dmi.resp.bits.resp
dmiResp.data := io.dmi.resp.bits.data
nopResp.addr := UInt(0)
nopResp.resp := UInt(0)
nopResp.data := UInt(0)
//--------------------------------------------------------
// Debug Access Chain Implementation
dmiAccessChain.io.capture.bits := Mux(busy, busyResp, Mux(io.dmi.resp.valid, dmiResp, nopResp))
when (dmiAccessChain.io.update.valid) {
skipOpReg := Bool(false)
downgradeOpReg := Bool(false)
}
when (dmiAccessChain.io.capture.capture) {
skipOpReg := busy
downgradeOpReg := (!busy & nonzeroResp)
stickyBusyReg := busy
stickyNonzeroRespReg := nonzeroResp
}
//--------------------------------------------------------
// Drive Ready Valid Interface
val dmiReqValidCheck = Wire(init = Bool(false))
assert(!(dmiReqValidCheck && io.dmi.req.fire()), "Conflicting updates for dmiReqValidReg, should not happen.");
when (dmiAccessChain.io.update.valid) {
when (skipOpReg) {
// Do Nothing
}.elsewhen (downgradeOpReg || (dmiAccessChain.io.update.bits.op === DMIConsts.dmi_OP_NONE)) {
//Do Nothing
dmiReqReg.addr := UInt(0)
dmiReqReg.data := UInt(0)
dmiReqReg.op := UInt(0)
}.otherwise {
dmiReqReg := dmiAccessChain.io.update.bits
dmiReqValidReg := Bool(true)
dmiReqValidCheck := Bool(true)
}
}
when (io.dmi.req.fire()) {
dmiReqValidReg := Bool(false)
}
io.dmi.resp.ready := dmiAccessChain.io.capture.capture
io.dmi.req.valid := dmiReqValidReg
// This is a name-based, not type-based assignment. Do these still work?
io.dmi.req.bits := dmiReqReg
//--------------------------------------------------------
// Actual JTAG TAP
val idcode = Wire(init = new JTAGIdcodeBundle().fromBits(0.U))
idcode.always1 := 1.U
idcode.version := c.idcodeVersion.U
idcode.partNumber := c.idcodePartNum.U
idcode.mfrId := io.jtag_mfr_id
val tapIO = JtagTapGenerator(irLength = 5,
instructions = Map(dtmJTAGAddrs.DMI_ACCESS -> dmiAccessChain,
dtmJTAGAddrs.DTM_INFO -> dtmInfoChain),
icode = Some(dtmJTAGAddrs.IDCODE)
)
tapIO.idcode.get := idcode
tapIO.jtag <> io.jtag
tapIO.control.jtag_reset := io.jtag_reset
//--------------------------------------------------------
// Reset Generation (this is fed back to us by the instantiating module,
// and is used to reset the debug registers).
io.fsmReset := tapIO.output.reset
}