From 55326c29bb34befca17c2192cbbaa3ffa7798daa Mon Sep 17 00:00:00 2001
From: "Wesley W. Terpstra" <wesley@sifive.com>
Date: Thu, 3 Nov 2016 19:05:22 -0700
Subject: [PATCH] tilelink2: Filter adapter removes some of the address space

---
 src/main/scala/diplomacy/Parameters.scala     | 11 +++++
 src/main/scala/uncore/tilelink2/Filter.scala  | 49 +++++++++++++++++++
 .../scala/uncore/tilelink2/Parameters.scala   |  2 +
 3 files changed, 62 insertions(+)
 create mode 100644 src/main/scala/uncore/tilelink2/Filter.scala

diff --git a/src/main/scala/diplomacy/Parameters.scala b/src/main/scala/diplomacy/Parameters.scala
index ddbe96d9..e494f6e7 100644
--- a/src/main/scala/diplomacy/Parameters.scala
+++ b/src/main/scala/diplomacy/Parameters.scala
@@ -104,6 +104,17 @@ case class AddressSet(base: BigInt, mask: BigInt) extends Ordered[AddressSet]
   // Widen the match function to ignore all bits in imask
   def widen(imask: BigInt) = AddressSet(base & ~imask, mask | imask)
 
+  // Return an AddressSet that only contains the addresses both sets contain
+  def intersect(x: AddressSet): Option[AddressSet] = {
+    if (!overlaps(x)) {
+      None
+    } else {
+      val r_mask = mask & x.mask
+      val r_base = base | x.base
+      Some(AddressSet(r_base, r_mask))
+    }
+  }
+
   // AddressSets have one natural Ordering (the containment order, if contiguous)
   def compare(x: AddressSet) = {
     val primary   = (this.base - x.base).signum // smallest address first
diff --git a/src/main/scala/uncore/tilelink2/Filter.scala b/src/main/scala/uncore/tilelink2/Filter.scala
new file mode 100644
index 00000000..c851f3f1
--- /dev/null
+++ b/src/main/scala/uncore/tilelink2/Filter.scala
@@ -0,0 +1,49 @@
+// See LICENSE for license details.
+
+package uncore.tilelink2
+
+import Chisel._
+import chisel3.internal.sourceinfo.SourceInfo
+import diplomacy._
+import scala.math.{min,max}
+
+class TLFilter(select: AddressSet) extends LazyModule
+{
+  val node = TLAdapterNode(
+    clientFn  = { case Seq(cp) => cp },
+    managerFn = { case Seq(mp) =>
+      mp.copy(managers = mp.managers.map { m =>
+        val filtered = m.address.map(_.intersect(select)).flatten
+        val cap = TransferSizes(1, select.alignment.toInt)
+        if (filtered.isEmpty) { None } else {
+          Some(m.copy(
+            address            = filtered,
+            supportsAcquire    = m.supportsAcquire   .intersect(cap),
+            supportsArithmetic = m.supportsArithmetic.intersect(cap),
+            supportsLogical    = m.supportsLogical   .intersect(cap),
+            supportsGet        = m.supportsGet       .intersect(cap),
+            supportsPutFull    = m.supportsPutFull   .intersect(cap),
+            supportsPutPartial = m.supportsPutPartial.intersect(cap),
+            supportsHint       = m.supportsHint      .intersect(cap)))
+        }
+      }.flatten)
+    })
+
+  lazy val module = new LazyModuleImp(this) {
+    val io = new Bundle {
+      val in  = node.bundleIn
+      val out = node.bundleOut
+    }
+    io.out <> io.in
+  }
+}
+
+object TLFilter
+{
+  // applied to the TL source node; y.node := TLBuffer(x.node)
+  def apply(select: AddressSet)(x: TLOutwardNode)(implicit sourceInfo: SourceInfo): TLOutwardNode = {
+    val filter = LazyModule(new TLFilter(select))
+    filter.node := x
+    filter.node
+  }
+}
diff --git a/src/main/scala/uncore/tilelink2/Parameters.scala b/src/main/scala/uncore/tilelink2/Parameters.scala
index 8ffea166..0a0da860 100644
--- a/src/main/scala/uncore/tilelink2/Parameters.scala
+++ b/src/main/scala/uncore/tilelink2/Parameters.scala
@@ -23,7 +23,9 @@ case class TLManagerParameters(
   fifoId:             Option[Int]   = None,
   customDTS:          Option[String]= None)
 {
+  require (!address.isEmpty)
   address.foreach { a => require (a.finite) }
+
   address.combinations(2).foreach { case Seq(x,y) => require (!x.overlaps(y)) }
   require (supportsPutFull.contains(supportsPutPartial))