From 27df04354f359d3120f35d2c4381a48b8b63db62 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@cs.berkeley.edu>
Date: Wed, 25 Nov 2015 20:04:31 -0800
Subject: [PATCH] Add ROM with NASTI interface

---
 uncore/src/main/scala/NastiROM.scala | 30 ++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 uncore/src/main/scala/NastiROM.scala

diff --git a/uncore/src/main/scala/NastiROM.scala b/uncore/src/main/scala/NastiROM.scala
new file mode 100644
index 00000000..ba1cef66
--- /dev/null
+++ b/uncore/src/main/scala/NastiROM.scala
@@ -0,0 +1,30 @@
+package uncore
+
+import Chisel._
+import junctions._
+import cde.{Parameters, Field}
+
+class NastiROM(contents: Seq[Byte])(implicit p: Parameters) extends Module {
+  val io = new NastiIO().flip
+  val ar = Queue(io.ar, 1)
+
+  // This assumes ROMs are in read-only parts of the address map.
+  // Reuse b_queue code from NastiErrorSlave if this assumption is bad.
+  when (ar.valid) { assert(ar.bits.len === UInt(0), "Can't burst-read from NastiROM") }
+  assert(!(io.aw.valid || io.w.valid), "Can't write to NastiROM")
+  io.aw.ready := Bool(false)
+  io.w.ready := Bool(false)
+  io.b.valid := Bool(false)
+
+  val byteWidth = io.r.bits.nastiXDataBits / 8
+  val rows = (contents.size + byteWidth - 1)/byteWidth + 1
+  val rom = Vec.tabulate(rows) { i =>
+    val slice = contents.slice(i*byteWidth, (i+1)*byteWidth)
+    UInt(slice.foldRight(BigInt(0)) { case (x,y) => (y << 8) + (x.toInt & 0xFF) })
+  }
+  val rdata_word = rom(if (rows == 1) UInt(0) else ar.bits.addr(log2Up(contents.size)-1,log2Up(byteWidth)))
+  val rdata = new LoadGen(Cat(UInt(1), ar.bits.size), ar.bits.addr, rdata_word, Bool(false), byteWidth).data
+
+  io.r <> ar
+  io.r.bits := NastiReadDataChannel(ar.bits.id, rdata)
+}