From 286b4b5b26af5f5978e02004e6ec1d28e2449333 Mon Sep 17 00:00:00 2001
From: Ross Thompson <stephen.thompson.37@us.af.mil>
Date: Wed, 23 Jun 2021 17:03:54 -0500
Subject: [PATCH] Partial addition of page table walker arbiter.

---
 wally-pipelined/src/lsu/lsu.sv    |  2 ++
 wally-pipelined/src/lsu/lsuArb.sv | 55 +++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 wally-pipelined/src/lsu/lsuArb.sv

diff --git a/wally-pipelined/src/lsu/lsu.sv b/wally-pipelined/src/lsu/lsu.sv
index eb6dae260..f20327bc4 100644
--- a/wally-pipelined/src/lsu/lsu.sv
+++ b/wally-pipelined/src/lsu/lsu.sv
@@ -41,6 +41,8 @@ module lsu (
   output logic             CommittedM,    
   output logic             SquashSCW,
   output logic             DataMisalignedM,
+
+  // part of the page table walker
   input logic              DisableTranslation,
 
   // address and write data
diff --git a/wally-pipelined/src/lsu/lsuArb.sv b/wally-pipelined/src/lsu/lsuArb.sv
new file mode 100644
index 000000000..14dcd6f72
--- /dev/null
+++ b/wally-pipelined/src/lsu/lsuArb.sv
@@ -0,0 +1,55 @@
+///////////////////////////////////////////
+// lsuArb.sv
+//
+// Written: Ross THompson and Kip Macsai-Goren
+// Modified: kmacsaigoren@hmc.edu June 23, 2021
+//
+// Purpose: LSU arbiter between the CPU's demand request for data memory and
+//          the page table walker
+// 
+// A component of the Wally configurable RISC-V project.
+// 
+// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, 
+// modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software 
+// is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 
+// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT 
+// OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+///////////////////////////////////////////
+
+`include "wally-config.vh"
+
+module lsuArb
+  (input logic clk, reset,
+
+   // signals from page table walker
+  output  logic [`XLEN-1:0] MMUReadPTE,
+  input logic             MMUTranslate,   // *** rename to HPTWReq
+  output  logic             MMUReady,
+  input logic [`XLEN-1:0] MMUPAdr,
+
+   // signal from CPU
+   input  logic [1:0]       MemRWM,
+   input  logic [2:0]       Funct3M,
+   input  logic [1:0]       AtomicM,
+   // back to CPU   
+   output logic             CommittedM,    
+   output logic             SquashSCW,
+   output logic             DataMisalignedM,
+
+   // to LSU   
+   output logic             DisableTranslation,   
+   output logic [1:0]       MemRWMtoLSU,
+   output logic [2:0]       Funct3MtoLSU,
+   output logic [1:0]       AtomicMtoLSU,
+
+
+	      
+endmodule