// See LICENSE.SiFive for license details.

package freechips.rocketchip.tile

import Chisel._

import freechips.rocketchip.config._
import freechips.rocketchip.rocket._
import freechips.rocketchip.util._

case object XLen extends Field[Int]
case object MaxHartIdBits extends Field[Int]

// These parameters can be varied per-core
trait CoreParams {
  val bootFreqHz: BigInt
  val useVM: Boolean
  val useUser: Boolean
  val useSupervisor: Boolean
  val useDebug: Boolean
  val useAtomics: Boolean
  val useAtomicsOnlyForIO: Boolean
  val useCompressed: Boolean
  val useVector: Boolean = false
  val useSCIE: Boolean
  val useRVE: Boolean
  val mulDiv: Option[MulDivParams]
  val fpu: Option[FPUParams]
  val fetchWidth: Int
  val decodeWidth: Int
  val retireWidth: Int
  val instBits: Int
  val nLocalInterrupts: Int
  val nPMPs: Int
  val pmpGranularity: Int
  val nBreakpoints: Int
  val useBPWatch: Boolean
  val mcontextWidth: Int
  val scontextWidth: Int
  val nPerfCounters: Int
  val haveBasicCounters: Boolean
  val haveFSDirty: Boolean
  val misaWritable: Boolean
  val haveCFlush: Boolean
  val nL2TLBEntries: Int
  val mtvecInit: Option[BigInt]
  val mtvecWritable: Boolean
  def customCSRs(implicit p: Parameters): CustomCSRs = new CustomCSRs

  def hasSupervisorMode: Boolean = useSupervisor || useVM
  def instBytes: Int = instBits / 8
  def fetchBytes: Int = fetchWidth * instBytes
  def lrscCycles: Int

  def dcacheReqTagBits: Int = 6

  def minFLen: Int = 32
  def vLen: Int = 0
  def sLen: Int = 0
  def eLen(xLen: Int, fLen: Int): Int = xLen max fLen
  def vMemDataBits: Int = 0
}

trait HasCoreParameters extends HasTileParameters {
  val coreParams: CoreParams = tileParams.core

  val minFLen = coreParams.fpu.map(_ => coreParams.minFLen).getOrElse(0)
  val fLen = coreParams.fpu.map(_.fLen).getOrElse(0)

  val usingMulDiv = coreParams.mulDiv.nonEmpty
  val usingFPU = coreParams.fpu.nonEmpty
  val usingAtomics = coreParams.useAtomics
  val usingAtomicsOnlyForIO = coreParams.useAtomicsOnlyForIO
  val usingAtomicsInCache = usingAtomics && !usingAtomicsOnlyForIO
  val usingCompressed = coreParams.useCompressed
  val usingVector = coreParams.useVector
  val usingSCIE = coreParams.useSCIE

  val retireWidth = coreParams.retireWidth
  val fetchWidth = coreParams.fetchWidth
  val decodeWidth = coreParams.decodeWidth

  val fetchBytes = coreParams.fetchBytes
  val coreInstBits = coreParams.instBits
  val coreInstBytes = coreInstBits/8
  val coreDataBits = xLen max fLen max vMemDataBits
  val coreDataBytes = coreDataBits/8
  def coreMaxAddrBits = paddrBits max vaddrBitsExtended

  val nBreakpoints = coreParams.nBreakpoints
  val nPMPs = coreParams.nPMPs
  val pmpGranularity = coreParams.pmpGranularity
  val nPerfCounters = coreParams.nPerfCounters
  val mtvecInit = coreParams.mtvecInit
  val mtvecWritable = coreParams.mtvecWritable

  def vLen = coreParams.vLen
  def sLen = coreParams.sLen
  def eLen = coreParams.eLen(xLen, fLen)
  def vMemDataBits = if (usingVector) coreParams.vMemDataBits else 0
  def maxVLMax = vLen

  if (usingVector) {
    require(isPow2(vLen), s"vLen ($vLen) must be a power of 2")
    require(eLen >= 32 && vLen % eLen == 0, s"eLen must divide vLen ($vLen) and be no less than 32")
    require(vMemDataBits >= eLen && vLen % vMemDataBits == 0, s"vMemDataBits ($vMemDataBits) must divide vLen ($vLen) and be no less than eLen ($eLen)")
  }

  lazy val hartIdLen: Int = p(MaxHartIdBits)
  lazy val resetVectorLen: Int = {
    val externalLen = paddrBits
    require(externalLen <= xLen, s"External reset vector length ($externalLen) must be <= XLEN ($xLen)")
    require(externalLen <= vaddrBitsExtended, s"External reset vector length ($externalLen) must be <= virtual address bit width ($vaddrBitsExtended)")
    externalLen
  }

  // Print out log of committed instructions and their writeback values.
  // Requires post-processing due to out-of-order writebacks.
  val enableCommitLog = false

}

abstract class CoreModule(implicit val p: Parameters) extends Module
  with HasCoreParameters

abstract class CoreBundle(implicit val p: Parameters) extends ParameterizedBundle()(p)
  with HasCoreParameters

class CoreInterrupts(implicit p: Parameters) extends TileInterrupts()(p) {
  val buserror = tileParams.beuAddr.map(a => Bool())
}

trait HasCoreIO extends HasTileParameters {
  implicit val p: Parameters
  val io = new CoreBundle()(p) {
    val hartid = UInt(hartIdLen.W).asInput
    val reset_vector = UInt(resetVectorLen.W).asInput
    val interrupts = new CoreInterrupts().asInput
    val imem  = new FrontendIO
    val dmem = new HellaCacheIO
    val ptw = new DatapathPTWIO().flip
    val fpu = new FPUCoreIO().flip
    val rocc = new RoCCCoreIO().flip
    val trace = Vec(coreParams.retireWidth, new TracedInstruction).asOutput
    val bpwatch = Vec(coreParams.nBreakpoints, new BPWatch(coreParams.retireWidth)).asOutput
    val cease = Bool().asOutput
    val wfi = Bool().asOutput
    val traceStall = Bool().asInput
  }
}
