From 484e8ce20b859d4f8b17f3e4b3f7f47f6692ca2a Mon Sep 17 00:00:00 2001
From: Howard Mao <zhehao.mao@gmail.com>
Date: Sun, 6 Dec 2015 02:57:45 -0800
Subject: [PATCH] add regression tests for catching specific memory bugs

---
 groundtest/src/main/scala/regression.scala | 115 +++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 groundtest/src/main/scala/regression.scala

diff --git a/groundtest/src/main/scala/regression.scala b/groundtest/src/main/scala/regression.scala
new file mode 100644
index 00000000..984e59bd
--- /dev/null
+++ b/groundtest/src/main/scala/regression.scala
@@ -0,0 +1,115 @@
+package groundtest
+
+import Chisel._
+import uncore._
+import junctions.{MMIOBase, ParameterizedBundle}
+import cde.Parameters
+
+class RegressionIO(implicit val p: Parameters) extends GroundTestIO()(p) {
+  val start = Bool(INPUT)
+}
+
+abstract class Regression(implicit val p: Parameters) extends Module {
+  val io = new RegressionIO
+}
+
+/**
+ * This was a bug in which the TileLinkIONarrower logic screwed up
+ * when a PutBlock request and a narrow Get request are sent to it at the
+ * same time. Repeating this sequence enough times will cause a queue to
+ * get filled up and deadlock the system.
+ */
+class IOGetAfterPutBlockRegression(implicit p: Parameters)
+    extends Regression()(p) with HasTileLinkParameters {
+
+  val nRuns = 7
+  val run = Reg(init = UInt(0, log2Up(nRuns + 1)))
+
+  val (put_beat, put_done) = Counter(
+    io.mem.acquire.fire() && io.mem.acquire.bits.hasData(), tlDataBeats)
+
+  val started = Reg(init = Bool(false))
+  val put_sent = Reg(init = Bool(false))
+  val get_sent = Reg(init = Bool(false))
+  val put_acked = Reg(init = Bool(false))
+  val get_acked = Reg(init = Bool(false))
+  val both_acked = put_acked && get_acked
+
+  when (!started && io.start) { started := Bool(true) }
+
+  io.mem.acquire.valid := !put_sent && started
+  io.mem.acquire.bits := PutBlock(
+    client_xact_id = UInt(0),
+    addr_block = UInt(0),
+    addr_beat = put_beat,
+    data = UInt(0))
+  io.mem.grant.ready := Bool(true)
+
+  io.cache.req.valid := !get_sent && started
+  io.cache.req.bits.addr := UInt(p(MMIOBase))
+  io.cache.req.bits.typ := MT_W
+  io.cache.req.bits.cmd := M_XRD
+  io.cache.req.bits.tag := UInt(0)
+  io.cache.req.bits.kill := Bool(false)
+  io.cache.req.bits.phys := Bool(true)
+
+  when (put_done) { put_sent := Bool(true) }
+  when (io.cache.req.fire()) { get_sent := Bool(true) }
+  when (io.mem.grant.fire()) { put_acked := Bool(true) }
+  when (io.cache.resp.valid) { get_acked := Bool(true) }
+
+  when (both_acked) {
+    when (run < UInt(nRuns - 1)) {
+      put_sent := Bool(false)
+      get_sent := Bool(false)
+    }
+    put_acked := Bool(false)
+    get_acked := Bool(false)
+    run := run + UInt(1)
+  }
+
+  io.finished := (run === UInt(nRuns))
+}
+
+class RegressionTest(implicit p: Parameters) extends GroundTest()(p) {
+
+  val regressions = Seq(
+    Module(new IOGetAfterPutBlockRegression))
+  val regressIOs = Vec(regressions.map(_.io))
+  val regress_idx = Reg(init = UInt(0, log2Up(regressions.size + 1)))
+  val all_done = (regress_idx === UInt(regressions.size))
+  val start = Reg(init = Bool(true))
+
+  when (start) { start := Bool(false) }
+
+  regressIOs.zipWithIndex.foreach { case (regress, i) =>
+    val me = regress_idx === UInt(i)
+    regress.start := me && start
+    regress.mem.acquire.ready := io.mem.acquire.ready && me
+    regress.mem.grant.valid := io.mem.grant.valid && me
+    regress.mem.grant.bits := io.mem.grant.bits
+    regress.cache.req.ready := io.cache.req.ready && me
+    regress.cache.resp.valid := io.cache.resp.valid && me
+  }
+
+  val cur_regression = regressIOs(regress_idx)
+  val cur_acquire = cur_regression.mem.acquire
+  val cur_grant = cur_regression.mem.grant
+  val cur_cache_req = cur_regression.cache.req
+
+  io.mem.acquire.valid := cur_acquire.valid
+  io.mem.acquire.bits := cur_acquire.bits
+  io.mem.grant.ready := cur_grant.ready
+  io.cache.req.valid := cur_cache_req.valid
+  io.cache.req.bits := cur_cache_req.bits
+
+  when (cur_regression.finished && !all_done) {
+    start := Bool(true)
+    regress_idx := regress_idx + UInt(1)
+  }
+
+  io.finished := all_done
+
+  val timeout = Timer(5000, start, cur_regression.finished)
+  assert(!timeout, "Regression timed out")
+}