From 66e9380cfbeac8bcc54f8552dbef5a78f45049c9 Mon Sep 17 00:00:00 2001
From: Ross Thompson <ross1728@gmail.com>
Date: Tue, 29 Mar 2022 19:12:29 -0500
Subject: [PATCH] Partial fix to allow byte write enables with fpga and still
 get a preload to work.

---
 pipelined/src/generic/flop/bram.sv |  47 +++++++++++++
 pipelined/src/uncore/ram.sv        |   2 +-
 pipelined/src/uncore/ram3.sv       | 105 +++++++++++++++++++++++++++++
 pipelined/testbench/testbench.sv   |  24 +++----
 4 files changed, 165 insertions(+), 13 deletions(-)
 create mode 100644 pipelined/src/generic/flop/bram.sv
 create mode 100644 pipelined/src/uncore/ram3.sv

diff --git a/pipelined/src/generic/flop/bram.sv b/pipelined/src/generic/flop/bram.sv
new file mode 100644
index 000000000..75fb76635
--- /dev/null
+++ b/pipelined/src/generic/flop/bram.sv
@@ -0,0 +1,47 @@
+// This model actually works correctly with vivado.
+
+
+module bram2p1r1w
+  #(
+	//--------------------------------------------------------------------------
+	parameter NUM_COL = 8,
+	parameter COL_WIDTH = 8,
+	parameter ADDR_WIDTH = 10,
+	// Addr Width in bits : 2 *ADDR_WIDTH = RAM Depth
+	parameter DATA_WIDTH = NUM_COL*COL_WIDTH // Data Width in bits
+	//----------------------------------------------------------------------
+	) (
+	   input logic 					 clk,
+	   input logic 					 enaA,
+	   input logic [ADDR_WIDTH-1:0]  addrA,
+	   output logic [DATA_WIDTH-1:0] doutA,
+	   input logic 					 enaB,
+	   input logic [NUM_COL-1:0] 	 weB,
+	   input logic [ADDR_WIDTH-1:0]  addrB,
+	   input logic [DATA_WIDTH-1:0]  dinB
+	   );
+  // Core Memory
+  logic [DATA_WIDTH-1:0] 			 RAM [(2**ADDR_WIDTH)-1:0];
+  integer 							 i;
+
+  initial begin
+	$readmemh("big64.txt", RAM);
+  end
+
+  // Port-A Operation
+  always @ (posedge clk) begin
+	if(enaA) begin
+	  doutA <= RAM[addrA];
+	end
+  end
+  // Port-B Operation:
+  always @ (posedge clk) begin
+	if(enaB) begin
+	  for(i=0;i<NUM_COL;i=i+1) begin
+		if(weB[i]) begin
+		  RAM[addrB][i*COL_WIDTH +: COL_WIDTH] <= dinB[i*COL_WIDTH +:COL_WIDTH];
+		end
+	  end
+	end
+  end
+endmodule // bytewrite_tdp_ram_rf
diff --git a/pipelined/src/uncore/ram.sv b/pipelined/src/uncore/ram.sv
index e9b0af32d..43065d1b0 100644
--- a/pipelined/src/uncore/ram.sv
+++ b/pipelined/src/uncore/ram.sv
@@ -30,7 +30,7 @@
 
 `include "wally-config.vh"
 
-module ram #(parameter BASE=0, RANGE = 65535) (
+module ramOld #(parameter BASE=0, RANGE = 65535) (
   input  logic             HCLK, HRESETn, 
   input  logic             HSELRam,
   input  logic [31:0]      HADDR,
diff --git a/pipelined/src/uncore/ram3.sv b/pipelined/src/uncore/ram3.sv
new file mode 100644
index 000000000..ad568b70c
--- /dev/null
+++ b/pipelined/src/uncore/ram3.sv
@@ -0,0 +1,105 @@
+///////////////////////////////////////////
+// ram.sv
+//
+// Written: David_Harris@hmc.edu 9 January 2021
+// Modified: 
+//
+// Purpose: On-chip RAM, external to core
+// 
+// A component of the Wally configurable RISC-V project.
+// 
+// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
+//
+// MIT LICENSE
+// 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.
+////////////////////////////////////////////////////////////////////////////////////////////////
+
+// True-Dual-Port BRAM with Byte-wide Write Enable
+// Read-First mode
+// bytewrite_tdp_ram_rf.v
+//
+
+`include "wally-config.vh"
+
+
+module ram #(parameter BASE=0, RANGE = 65535) (
+  input  logic             HCLK, HRESETn, 
+  input  logic             HSELRam,
+  input  logic [31:0]      HADDR,
+  input  logic             HWRITE,
+  input  logic             HREADY,
+  input  logic [1:0]       HTRANS,
+  input  logic [`XLEN-1:0] HWDATA,
+  input  logic [3:0]       HSIZED,
+  output logic [`XLEN-1:0] HREADRam,
+  output logic             HRESPRam, HREADYRam
+);
+
+  logic [`XLEN/8-1:0] 		  ByteMaskM;
+  logic [31:0]        HWADDR, A;
+  logic				  prevHREADYRam, risingHREADYRam;
+  logic				  initTrans;
+  logic				  memwrite;
+  logic [3:0] 		  busycount;
+  
+  swbytemask swbytemask(.HSIZED, .HADDRD(A[2:0]), .ByteMask(ByteMaskM));
+
+  assign initTrans = HREADY & HSELRam & (HTRANS != 2'b00);
+
+  // *** this seems like a weird way to use reset
+  flopenr #(1) memwritereg(HCLK, 1'b0, initTrans | ~HRESETn, HSELRam &  HWRITE, memwrite);
+  flopenr #(32)   haddrreg(HCLK, 1'b0, initTrans | ~HRESETn, HADDR, A);
+  // busy FSM to extend READY signal
+  always @(posedge HCLK, negedge HRESETn) 
+    if (~HRESETn) begin
+      busycount <= 0;
+      HREADYRam <= #1 0;
+    end else begin
+      if (initTrans) begin
+        busycount <= 0;
+        HREADYRam <= #1 0;
+      end else if (~HREADYRam) begin
+        if (busycount == 0) begin // Ram latency, for testing purposes.  *** test with different values such as 2
+          HREADYRam <= #1 1;
+        end else begin
+          busycount <= busycount + 1;
+        end
+      end
+    end
+  assign HRESPRam = 0; // OK
+
+  localparam ADDR_WDITH = $clog2(RANGE/8);
+  
+  // Rising HREADY edge detector
+  //   Indicates when ram is finishing up
+  //   Needed because HREADY may go high for other reasons,
+  //   and we only want to write data when finishing up.
+  flopenr #(1) prevhreadyRamreg(HCLK,~HRESETn, 1'b1, HREADYRam,prevHREADYRam);
+  assign risingHREADYRam = HREADYRam & ~prevHREADYRam;
+
+  always @(posedge HCLK)
+    HWADDR <= #1 A;
+
+  bram2p1r1w #(`XLEN/8, 8, ADDR_WDITH)
+  memory(.clk(HCLK), .enaA(1'b1),
+		 .addrA(A[ADDR_WDITH+2:3]), .doutA(HREADRam),
+		 .enaB(memwrite & risingHREADYRam), .weB(ByteMaskM),
+		 .addrB(HWADDR[ADDR_WDITH+2:3]), .dinB(HWDATA));
+		 
+  
+endmodule
+  
diff --git a/pipelined/testbench/testbench.sv b/pipelined/testbench/testbench.sv
index 775a21a7f..9bb2ed029 100644
--- a/pipelined/testbench/testbench.sv
+++ b/pipelined/testbench/testbench.sv
@@ -178,7 +178,7 @@ logic [3:0] dummy;
       // the design.
       if (TEST == "coremark") 
         for (i=MemStartAddr; i<MemEndAddr; i = i+1) 
-          dut.uncore.ram.ram.RAM[i] = 64'h0; 
+          dut.uncore.ram.ram.memory.RAM[i] = 64'h0; 
 
       // read test vectors into memory
       pathname = tvpaths[tests[0].atoi()];
@@ -186,9 +186,9 @@ logic [3:0] dummy;
         pathname = tvpaths[0];
       else pathname = tvpaths[1]; */
       memfilename = {pathname, tests[test], ".elf.memfile"};
-      if (`IMEM == `MEM_TIM) $readmemh(memfilename, dut.core.ifu.irom.irom.ram.RAM);
-      else              $readmemh(memfilename, dut.uncore.ram.ram.RAM);
-      if (`DMEM == `MEM_TIM) $readmemh(memfilename, dut.core.lsu.dtim.dtim.ram.RAM);
+      if (`IMEM == `MEM_TIM) $readmemh(memfilename, dut.core.ifu.irom.irom.ram.memory.RAM);
+      else              $readmemh(memfilename, dut.uncore.ram.ram.memory.RAM);
+      if (`DMEM == `MEM_TIM) $readmemh(memfilename, dut.core.lsu.dtim.dtim.ram.memory.RAM);
 
       ProgramAddrMapFile = {pathname, tests[test], ".elf.objdump.addr"};
       ProgramLabelMapFile = {pathname, tests[test], ".elf.objdump.lab"};
@@ -246,11 +246,11 @@ logic [3:0] dummy;
         /* verilator lint_off INFINITELOOP */
         while (signature[i] !== 'bx) begin
           logic [`XLEN-1:0] sig;
-          if (`DMEM == `MEM_TIM) sig = dut.core.lsu.dtim.dtim.ram.RAM[testadr+i];
-          else                   sig = dut.uncore.ram.ram.RAM[testadr+i];
+          if (`DMEM == `MEM_TIM) sig = dut.core.lsu.dtim.dtim.ram.memory.RAM[testadr+i];
+          else                   sig = dut.uncore.ram.ram.memory.RAM[testadr+i];
 //          $display("signature[%h] = %h sig = %h", i, signature[i], sig);
           if (signature[i] !== sig &
-          //if (signature[i] !== dut.core.lsu.dtim.ram.RAM[testadr+i] &
+          //if (signature[i] !== dut.core.lsu.dtim.ram.memory.RAM[testadr+i] &
 	      (signature[i] !== DCacheFlushFSM.ShadowRAM[testadr+i])) begin  // ***i+1?
             if ((signature[i] !== '0 | signature[i+4] !== 'x)) begin
 //            if (signature[i+4] !== 'bx | (signature[i] !== 32'hFFFFFFFF & signature[i] !== 32'h00000000)) begin
@@ -260,7 +260,7 @@ logic [3:0] dummy;
               errors = errors+1;
               $display("  Error on test %s result %d: adr = %h sim (D$) %h sim (DMEM) = %h, signature = %h", 
                     tests[test], i, (testadr+i)*(`XLEN/8), DCacheFlushFSM.ShadowRAM[testadr+i], sig, signature[i]);
-                    //   tests[test], i, (testadr+i)*(`XLEN/8), DCacheFlushFSM.ShadowRAM[testadr+i], dut.core.lsu.dtim.ram.RAM[testadr+i], signature[i]);
+                    //   tests[test], i, (testadr+i)*(`XLEN/8), DCacheFlushFSM.ShadowRAM[testadr+i], dut.core.lsu.dtim.ram.memory.RAM[testadr+i], signature[i]);
               $stop;//***debug
             end
           end
@@ -283,10 +283,10 @@ logic [3:0] dummy;
         else begin
             //pathname = tvpaths[tests[0]];
             memfilename = {pathname, tests[test], ".elf.memfile"};
-            //$readmemh(memfilename, dut.uncore.ram.ram.RAM);
-            if (`IMEM == `MEM_TIM) $readmemh(memfilename, dut.core.ifu.irom.irom.ram.RAM);
-            else                   $readmemh(memfilename, dut.uncore.ram.ram.RAM);
-            if (`DMEM == `MEM_TIM) $readmemh(memfilename, dut.core.lsu.dtim.dtim.ram.RAM);
+            //$readmemh(memfilename, dut.uncore.ram.ram.memory.RAM);
+            if (`IMEM == `MEM_TIM) $readmemh(memfilename, dut.core.ifu.irom.irom.ram.memory.RAM);
+            else                   $readmemh(memfilename, dut.uncore.ram.ram.memory.RAM);
+            if (`DMEM == `MEM_TIM) $readmemh(memfilename, dut.core.lsu.dtim.dtim.ram.memory.RAM);
 
             ProgramAddrMapFile = {pathname, tests[test], ".elf.objdump.addr"};
             ProgramLabelMapFile = {pathname, tests[test], ".elf.objdump.lab"};