From 171c87002e02c7f699e7980a8183c77b98d5ab50 Mon Sep 17 00:00:00 2001
From: Andrew Waterman <waterman@eecs.berkeley.edu>
Date: Thu, 3 May 2012 04:21:11 -0700
Subject: [PATCH] reduce HTIF clock divider for now

---
 rocket/src/main/scala/slowio.scala | 5 +++--
 rocket/src/main/scala/top.scala    | 6 +++---
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/rocket/src/main/scala/slowio.scala b/rocket/src/main/scala/slowio.scala
index 395bdc8d..e54996ef 100644
--- a/rocket/src/main/scala/slowio.scala
+++ b/rocket/src/main/scala/slowio.scala
@@ -3,7 +3,7 @@ package rocket
 import Chisel._
 import Constants._
 
-class slowIO[T <: Data](divisor: Int, hold_cycles: Int)(data: => T) extends Component
+class slowIO[T <: Data](val divisor: Int, hold_cycles_in: Int = -1)(data: => T) extends Component
 {
   val io = new Bundle {
     val out_fast = new ioDecoupled()(data).flip
@@ -15,8 +15,9 @@ class slowIO[T <: Data](divisor: Int, hold_cycles: Int)(data: => T) extends Comp
     val clk_slow = Bool(OUTPUT)
   }
 
+  val hold_cycles = if (hold_cycles_in == -1) divisor/4 else hold_cycles_in
   require((divisor & (divisor-1)) == 0)
-  require(hold_cycles < divisor/2 && hold_cycles >= 2)
+  require(hold_cycles < divisor/2 && hold_cycles >= 1)
 
   val cnt = Reg() { UFix(width = log2up(divisor)) }
   cnt := cnt + UFix(1)
diff --git a/rocket/src/main/scala/top.scala b/rocket/src/main/scala/top.scala
index 4ebb94d8..55bf08f9 100644
--- a/rocket/src/main/scala/top.scala
+++ b/rocket/src/main/scala/top.scala
@@ -16,7 +16,7 @@ class ioTop(htif_width: Int) extends Bundle  {
 
 class Top extends Component
 {
-  val clkdiv = 32
+  val clkdiv = 8
   val htif_width = 8
   val io = new ioTop(htif_width)
 
@@ -53,7 +53,7 @@ class Top extends Component
   hub.io.mem.resp.bits := Mux(io.mem_backup_en, mem_serdes.io.wide.resp.bits, io.mem.resp.bits)
 
   // pad out the HTIF using a divided clock
-  val hio = (new slowIO(clkdiv, 4)) { Bits(width = htif_width) }
+  val hio = (new slowIO(clkdiv)) { Bits(width = htif_width) }
   htif.io.host.out <> hio.io.out_fast
   io.host.out <> hio.io.out_slow
   htif.io.host.in <> hio.io.in_fast
@@ -61,7 +61,7 @@ class Top extends Component
   io.host_clk := hio.io.clk_slow
 
   // pad out the backup memory link with the HTIF divided clk
-  val mio = (new slowIO(clkdiv, 4)) { Bits(width = MEM_BACKUP_WIDTH) }
+  val mio = (new slowIO(clkdiv)) { Bits(width = MEM_BACKUP_WIDTH) }
   mem_serdes.io.narrow.req <> mio.io.out_fast
   io.mem_backup.req <> mio.io.out_slow
   mem_serdes.io.narrow.resp.valid := mio.io.in_fast.valid