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tilelink: PMP controlled BusBlocker prevents bus accesses

This commit is contained in:
Wesley W. Terpstra 2017-08-07 18:30:38 -07:00
parent 6d1d285464
commit 0d76e96b88
2 changed files with 119 additions and 7 deletions

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@ -0,0 +1,108 @@
// See LICENSE.SiFive for license details.
package freechips.rocketchip.devices.tilelink
import Chisel._
import freechips.rocketchip.config.Parameters
import freechips.rocketchip.diplomacy._
import freechips.rocketchip.regmapper._
import freechips.rocketchip.tilelink._
import freechips.rocketchip.util._
case class BusBlockerParams(
controlAddress: BigInt,
controlBeatBytes: Int,
deviceBeatBytes: Int,
pmpRegisters: Int)
{
val page = 4096
val size = (((pmpRegisters * 8) + page - 1) / page) * page
require (pmpRegisters > 0)
require (controlAddress > 0)
require (controlAddress % size == 0)
require (controlBeatBytes > 0 && isPow2(controlBeatBytes))
require (deviceBeatBytes > 0 && isPow2(deviceBeatBytes))
}
case class DevicePMPParams(addressBits: Int)
class DevicePMP(params: DevicePMPParams) extends GenericParameterizedBundle(params)
{
require (params.addressBits > 12)
val l = UInt(width = 1) // locked
val a = UInt(width = 1) // LSB of A (0=disabled, 1=TOR)
val r = UInt(width = 1)
val w = UInt(width = 1)
val addr_hi = UInt(width = params.addressBits-12)
def address = Cat(addr_hi, UInt(0, width=12))
def fields(locked: Bool): Seq[RegField] = {
def field(bits: Int, reg: UInt) =
RegField(bits, RegReadFn(reg), RegWriteFn((wen, data) => {
when (wen && !locked) { reg := data }
Bool(true)
}))
Seq(
RegField(10),
field(params.addressBits-12, addr_hi),
RegField(56 - (params.addressBits-2)),
field(1, r),
field(1, w),
RegField(1), // x
field(1, a),
RegField(3), // a high + 2 reserved
field(1, l))
}
}
object DevicePMP
{
def apply(addressBits: Int) = {
val out = Wire(new DevicePMP(DevicePMPParams(addressBits)))
out.l := UInt(0)
out.a := UInt(1) // TOR
out.r := UInt(0)
out.w := UInt(0)
out.addr_hi := ~UInt(0, width=addressBits-12)
out
}
}
class BusBlocker(params: BusBlockerParams)(implicit p: Parameters) extends TLBusBypassBase(params.deviceBeatBytes)
{
val device = new SimpleDevice("bus-blocker", Seq("sifive,bus-blocker0"))
val controlNode = TLRegisterNode(
address = Seq(AddressSet(params.controlAddress, params.size-1)),
device = device,
beatBytes = params.controlBeatBytes)
lazy val module = new LazyModuleImp(this) {
val io = new Bundle {
val ctl = controlNode.bundleIn
val in = nodeIn.bundleIn
val out = nodeOut.bundleOut
}
// We need to be able to represent +1 larger than the largest populated address
val addressBits = log2Ceil(nodeOut.edgesOut(0).manager.maxAddress+1+1)
val pmps = RegInit(Vec.fill(params.pmpRegisters) { DevicePMP(addressBits) })
val locks = (pmps.map(_.l) zip (UInt(0) +: pmps.map(_.l))) map { case (x, n) => x | n }
controlNode.regmap(0 -> (pmps zip locks).map { case (p, l) => p.fields(l(0)) }.toList.flatten)
val in = io.in(0)
val edge = nodeIn.edgesIn(0)
// Determine if a request is allowed
val needW = in.a.bits.opcode =/= TLMessages.Get
val needR = in.a.bits.opcode =/= TLMessages.PutFullData && in.a.bits.opcode =/= TLMessages.PutPartialData
val lte = Bool(false) +: pmps.map(in.a.bits.address < _.address)
val sel = (pmps.map(_.a) zip (lte.init zip lte.tail)) map { case (a, (l, r)) => a(0) && !l && r }
val ok = pmps.map(p => (p.r(0) || !needR) && (p.w(0) || !needW))
val allow = PriorityMux(sel :+ Bool(true), ok :+ Bool(true)) // no match => allow
bar.module.io.bypass := !allow
}
}

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@ -10,19 +10,23 @@ import freechips.rocketchip.tilelink._
import freechips.rocketchip.util._
import scala.math.min
class TLBusBypass(beatBytes: Int)(implicit p: Parameters) extends LazyModule
abstract class TLBusBypassBase(beatBytes: Int)(implicit p: Parameters) extends LazyModule
{
private val nodeIn = TLInputNode()
private val nodeOut = TLOutputNode()
protected val nodeIn = TLInputNode()
protected val nodeOut = TLOutputNode()
val node = NodeHandle(nodeIn, nodeOut)
private val bar = LazyModule(new TLBusBypassBar)
private val everything = Seq(AddressSet(0, BigInt("ffffffffffffffffffffffffffffffff", 16))) // 128-bit
private val error = LazyModule(new TLError(ErrorParams(everything), beatBytes))
protected val bar = LazyModule(new TLBusBypassBar)
protected val everything = Seq(AddressSet(0, BigInt("ffffffffffffffffffffffffffffffff", 16))) // 128-bit
protected val error = LazyModule(new TLError(ErrorParams(everything), beatBytes))
bar.node := nodeIn
error.node := bar.node
nodeOut := bar.node
}
class TLBusBypass(beatBytes: Int)(implicit p: Parameters) extends TLBusBypassBase(beatBytes)
{
lazy val module = new LazyModuleImp(this) {
val io = new Bundle {
val in = nodeIn.bundleIn
@ -33,7 +37,7 @@ class TLBusBypass(beatBytes: Int)(implicit p: Parameters) extends LazyModule
}
}
private class TLBusBypassBar(implicit p: Parameters) extends LazyModule
class TLBusBypassBar(implicit p: Parameters) extends LazyModule
{
// The client only sees the second slave port
val node = TLNexusNode(