riscv/rocket-chip
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Merge pull request #1238 from freechipsproject/error-bifurcate

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Error: don't be an exception wrt. caching
This commit is contained in:
Wesley W. Terpstra 2018-02-15 22:19:27 -08:00 committed by GitHub
commit bb1976552f
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4 changed files with 42 additions and 31 deletions
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48
src/main/scala/devices/tilelink/Error.scala
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@ -10,7 +10,7 @@ import freechips.rocketchip.tilelink._
import freechips.rocketchip.util._
import scala.math.min
case class ErrorParams(address: Seq[AddressSet], maxAtomic: Int, maxTransfer: Int)
case class ErrorParams(address: Seq[AddressSet], maxAtomic: Int, maxTransfer: Int, acquire: Boolean = false)
{
require (1 <= maxAtomic && maxAtomic <= maxTransfer && maxTransfer <= 4096)
}
@ -26,10 +26,10 @@ abstract class DevNullDevice(params: ErrorParams, beatBytes: Int = 4)
Seq(TLManagerParameters(
address = params.address,
resources = device.reg("mem"),
regionType = RegionType.UNCACHEABLE,
regionType = if (params.acquire) RegionType.TRACKED else RegionType.UNCACHEABLE,
executable = true,
supportsAcquireT = xfer,
supportsAcquireB = xfer,
supportsAcquireT = if (params.acquire) xfer else TransferSizes.none,
supportsAcquireB = if (params.acquire) xfer else TransferSizes.none,
supportsGet = xfer,
supportsPutPartial = xfer,
supportsPutFull = xfer,
@ -52,19 +52,15 @@ class TLError(params: ErrorParams, beatBytes: Int = 4)(implicit p: Parameters)
val (in, edge) = node.in(0)
val a = Queue(in.a, 1)
val c = Queue(in.c, 1)
val da = Wire(in.d)
val dc = Wire(in.d)
val a_last = edge.last(a)
val c_last = edge.last(c)
val da_last = edge.last(da)
val dc_last = edge.last(dc)
a.ready := (da.ready && da_last) || !a_last
da.valid := a.valid && a_last
val a_opcodes = Vec(AccessAck, AccessAck, AccessAckData, AccessAckData, AccessAckData, HintAck, Grant)
val a_opcodes = Vec(AccessAck, AccessAck, AccessAckData, AccessAckData, AccessAckData, HintAck, Grant, Grant)
da.bits.opcode := a_opcodes(a.bits.opcode)
da.bits.param := UInt(0) // toT, but error grants must be handled transiently (ie: you don't keep permissions)
da.bits.size := a.bits.size
@ -73,21 +69,31 @@ class TLError(params: ErrorParams, beatBytes: Int = 4)(implicit p: Parameters)
da.bits.data := UInt(0)
da.bits.error := Bool(true)
c.ready := (dc.ready && dc_last) || !c_last
dc.valid := c.valid && c_last
if (params.acquire) {
val c = Queue(in.c, 1)
val dc = Wire(in.d)
dc.bits.opcode := ReleaseAck
dc.bits.param := Vec(toB, toN, toN)(c.bits.param)
dc.bits.size := c.bits.size
dc.bits.source := c.bits.source
dc.bits.sink := UInt(0)
dc.bits.data := UInt(0)
dc.bits.error := Bool(true)
val c_last = edge.last(c)
val dc_last = edge.last(dc)
// Combine response channels
TLArbiter.lowest(edge, in.d, dc, da)
c.ready := (dc.ready && dc_last) || !c_last
dc.valid := c.valid && c_last
// We never probe or issue B requests; we are UNCACHED
dc.bits.opcode := ReleaseAck
dc.bits.param := Vec(toB, toN, toN)(c.bits.param)
dc.bits.size := c.bits.size
dc.bits.source := c.bits.source
dc.bits.sink := UInt(0)
dc.bits.data := UInt(0)
dc.bits.error := Bool(true)
// Combine response channels
TLArbiter.lowest(edge, in.d, dc, da)
} else {
in.d <> da
}
// We never probe or issue B requests
in.b.valid := Bool(false)
// Sink GrantAcks

2
src/main/scala/rocket/HellaCache.scala
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@ -163,7 +163,7 @@ abstract class HellaCache(hartid: Int)(implicit p: Parameters) extends LazyModul
TLClientParameters(
name = s"Core ${hartid} DCache",
sourceId = IdRange(0, firstMMIO),
supportsProbe = TransferSizes(1, cfg.blockBytes)),
supportsProbe = TransferSizes(cfg.blockBytes, cfg.blockBytes)),
TLClientParameters(
name = s"Core ${hartid} DCache MMIO",
sourceId = IdRange(firstMMIO, firstMMIO+cfg.nMMIOs),

17
src/main/scala/tilelink/CacheCork.scala
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@ -26,10 +26,10 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
(node.in zip node.out) foreach { case ((in, edgeIn), (out, edgeOut)) =>
val clients = edgeIn.client.clients
val caches = clients.filter(_.supportsProbe)
require (clients.size == 1 || caches.size == 0 || unsafe, "Only one client can safely use a TLCacheCork")
require (caches.size <= 1 || unsafe, "Only one caching client allowed")
require (clients.size == 1 || caches.size == 0 || unsafe, s"Only one client can safely use a TLCacheCork; ${clients.map(_.name)}")
require (caches.size <= 1 || unsafe, s"Only one caching client allowed; ${clients.map(_.name)}")
edgeOut.manager.managers.foreach { case m =>
require (!m.supportsAcquireB || unsafe, "Cannot support caches beyond the Cork")
require (!m.supportsAcquireB || unsafe, s"Cannot support caches beyond the Cork; ${m.name}")
require (m.regionType <= RegionType.UNCACHED)
}
@ -39,8 +39,15 @@ class TLCacheCork(unsafe: Boolean = false)(implicit p: Parameters) extends LazyM
// A caveat is that we get Acquire+Release with the same source and must keep the
// source unique after transformation onto the A channel.
// The coding scheme is:
// Put: 1, Release: 0 => AccessAck
// *: 0, Acquire: 1 => AccessAckData
// Release, AcquireBlock.BtoT, AcquirePerm => instant response
// Put{Full,Partial}Data: 1, ReleaseData: 0 => AccessAck
// {Arithmetic,Logical}Data,Get: 0, Acquire: 1 => AccessAckData
// Hint:0 => HintAck
// The CacheCork can potentially send the same source twice if a client sends
// simultaneous Release and AMO/Get with the same source. It will still correctly
// decode the messages based on the D.opcode, but the double use violates the spec.
// Fortunately, no masters we know of behave this way!
// Take requests from A to A or D (if BtoT Acquire)
val a_a = Wire(out.a)

6
src/main/scala/tilelink/Parameters.scala
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@ -40,7 +40,7 @@ case class TLManagerParameters(
require (supportsAcquireB.contains(supportsAcquireT), s"AcquireB($supportsAcquireB) < AcquireT($supportsAcquireT)")
// Make sure that the regionType agrees with the capabilities
require (!supportsAcquireB || regionType >= RegionType.UNCACHEABLE) // acquire -> uncached, tracked, cached
require (!supportsAcquireB || regionType >= RegionType.UNCACHED) // acquire -> uncached, tracked, cached
require (regionType <= RegionType.UNCACHED || supportsAcquireB) // tracked, cached -> acquire
require (regionType != RegionType.UNCACHED || supportsGet) // uncached -> supportsGet
@ -186,7 +186,7 @@ case class TLClientParameters(
name: String,
sourceId: IdRange = IdRange(0,1),
nodePath: Seq[BaseNode] = Seq(),
requestFifo: Boolean = false, // only a request, not a requirement
requestFifo: Boolean = false, // only a request, not a requirement. applies to A, not C.
// Supports both Probe+Grant of these sizes
supportsProbe: TransferSizes = TransferSizes.none,
supportsArithmetic: TransferSizes = TransferSizes.none,
@ -204,8 +204,6 @@ case class TLClientParameters(
require (supportsProbe.contains(supportsPutFull))
require (supportsProbe.contains(supportsPutPartial))
require (supportsProbe.contains(supportsHint))
// If you need FIFO, you better not be TL-C (due to independent A vs. C order)
require (!requestFifo || !supportsProbe)
val maxTransfer = List(
supportsProbe.max,