bsg_alloc_wavefront

bsg_misc/bsg_alloc_wavefront.sv

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+/**
+ *    bsg_alloc_wavefront.sv
+ *
+ *    @author Tommy Jung
+ *
+ *    N:N wavefront allocator;
+ *
+ *    Based on "Efficient microarchitecture for network-on-chip routers",
+ *               Daniel U Becker, PhD Thesis, Stanford University, 2012.
+ *               (Section 3.3)
+ *
+ *    This module coordinates an arbitration between N agents and N resources.
+ *    Each agent may request for one or more resources.
+ *    Given a request matrix (row=agent, col=resource), it generates a grant matrix, such that,
+ *    - no resource granted for more than one agent.
+ *    - no agent granted more than one resource.
+ *    - no grant when there is no request.
+ *    - if there is a request, which is not granted, it implies some other grant in the same column or row.
+ *    It tries to maximize the number of matches between agents and resources for improved utilization.
+ *
+ */
+
+
+`include "bsg_defines.sv"
+
+
+
+module bsg_alloc_wavefront
+  #(parameter `BSG_INV_PARAM(width_p) // Number of Agents/Resources;
+  )
+  (
+    input clk_i
+    , input reset_i
+
+    // 2-D bit matrix;
+    // [agent_idx][resource_idx] 
+    , input        [width_p-1:0][width_p-1:0] reqs_i
+    , output logic [width_p-1:0][width_p-1:0] grants_o
+
+    // assert yumi_i to accept the grant matrix;
+    , input yumi_i
+  );
+
+
+  // Rotate reqs_i so that diagonal elements end up in the same row;
+  logic [width_p-1:0][width_p-1:0] reqs_rotate;
+
+  for (genvar i = 0; i < width_p; i++) begin
+    for (genvar j = 0; j < width_p; j++) begin
+      assign reqs_rotate[i][j] = reqs_i[(width_p+i-j)%width_p][j];
+    end
+  end
+
+
+  // priority diagonal signal;;
+  logic [width_p-1:0] priority_diag;
+
+
+  // cell array;
+  logic [(2*width_p)-1-1:0][width_p-1:0] y_li, x_li, priority_li, req_li, y_lo, x_lo, grant_lo;
+
+  for (genvar i = 0; i < (2*width_p)-1; i++) begin: y
+    for (genvar j = 0; j < width_p; j++) begin: x
+      // wavefront cell;
+      bsg_alloc_wavefront_cell cell0 (
+        .x_i          (x_li[i][j])
+        ,.y_i         (y_li[i][j])
+        ,.priority_i  (priority_li[i][j])
+        ,.req_i       (req_li[i][j])
+        ,.y_o         (y_lo[i][j])
+        ,.x_o         (x_lo[i][j])
+        ,.grant_o     (grant_lo[i][j])
+      );
+
+      // connect y;
+      if (i == 0) begin
+        assign y_li[i][j] = 1'b0;
+      end
+      else begin
+        assign y_li[i][j] = y_lo[i-1][j];
+      end
+
+      // connect x;
+      if (i == 0) begin
+        assign x_li[i][j]  = 1'b0;
+      end
+      else begin
+        if (j == 0) begin
+          assign x_li[i][j]  = x_lo[i-1][width_p-1];
+        end
+        else begin
+          assign x_li[i][j]  = x_lo[i-1][j-1];
+        end
+      end
+
+      // connect priority;
+      if (i < width_p) begin
+        assign priority_li[i][j] = priority_diag[i];
+      end
+      else begin
+        assign priority_li[i][j] = 1'b0;
+      end
+
+      // connect req;
+      assign req_li[i][j] = reqs_rotate[i%width_p][j];
+    end    
+  end
+
+
+
+
+
+  // Priority diagonal generator;
+  logic [width_p-1:0] rr_reqs;
+
+  // OR reduce;
+  for (genvar i = 0; i < width_p; i++) begin
+    assign rr_reqs[i] = |reqs_rotate[i];
+  end
+
+  bsg_arb_round_robin #(
+    .width_p(width_p)
+  ) rr0 (
+    .clk_i(clk_i)
+    ,.reset_i(reset_i)
+
+    ,.reqs_i(rr_reqs)
+    ,.grants_o(priority_diag)
+    ,.yumi_i(yumi_i)
+  );
+
+
+  ////////////////////////
+  // Connect grant output;
+  ////////////////////////
+
+  // transpose grant_lo;
+  logic [width_p-1:0][(2*width_p)-1-1:0] grants_tp;
+  bsg_transpose #(
+    .width_p(width_p)
+    ,.els_p((2*width_p)-1)
+  ) tp0 (
+    .i(grant_lo)
+    ,.o(grants_tp)
+  );
+
+  // Apply OR;
+  logic [width_p-1:0][width_p-1:0] grants_or;
+  for (genvar i = 0; i < width_p; i++) begin
+    assign grants_or[i] = grants_tp[i][0+:width_p] | {1'b0, grants_tp[i][width_p+:width_p-1]};
+  end
+
+  // rotate;
+  logic [width_p-1:0][width_p-1:0] grants_rotate;
+  for (genvar i = 0; i < width_p; i++) begin
+    assign grants_rotate[i] = width_p'({grants_or[i], grants_or[i]} >> i);
+  end
+
+
+  // transpose it back;
+  bsg_transpose #(
+    .width_p(width_p)
+    ,.els_p(width_p)
+  ) tp1 (
+    .i(grants_rotate)
+    ,.o(grants_o)
+  );
+
+
+
+endmodule
+
+
+`BSG_ABSTRACT_MODULE(bsg_alloc_wavefront)
+
+
+
+// private module for bsg_alloc_wavefront;
+module bsg_alloc_wavefront_cell
+  (
+    input x_i
+    , input y_i
+    , input priority_i
+    , input req_i
+    , output logic y_o
+    , output logic x_o
+    , output logic grant_o
+  );
+
+  wire yp = y_i | priority_i;
+  wire xp = x_i | priority_i;
+
+  wire grant = yp & xp & req_i;
+  assign grant_o = grant;
+
+  assign x_o = xp & ~grant;
+  assign y_o = yp & ~grant;
+
+endmodule
+
+
+`BSG_ABSTRACT_MODULE(bsg_alloc_wavefront_cell)
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+

testing/bsg_misc/bsg_alloc_wavefront/.gitignore

@@ -0,0 +1 @@
+vc_hdrs.h

testing/bsg_misc/bsg_alloc_wavefront/Makefile

@@ -0,0 +1,32 @@
+export THIS_DIR = $(abspath .)
+export BASEJUMP_STL_DIR = $(shell git rev-parse --show-toplevel)
+export CADENV_DIR = $(abspath $(BASEJUMP_STL_DIR)/../bsg_cadenv)
+
+include $(CADENV_DIR)/cadenv.mk
+
+VCS_FLAGS 	+= -R -full64 +v2k -sverilog
+VCS_FLAGS 	+= -timescale=1ps/1ps
+VCS_FLAGS 	+= +lint=all,noSVA-UA,noSVA-NSVU,noVCDE,noNS -top testbench
+VCS_FLAGS 	+= -licqueue
+VCS_FLAGS 	+= -reportstats
+VCS_FLAGS 	+= -assert svaext
+VCS_FLAGS 	+= -l run.log
+VCS_FLAGS 	+= -debug_pp
+VCS_FLAGS 	+= +vcs+vcdpluson
+#VCS_FLAGS 	+= +vcs+nostdout
+
+VCS_INCDIR 	+= +incdir+$(BASEJUMP_STL_DIR)/bsg_misc
+
+VCS_DEFINES += 
+
+run:
+	vcs -R -full64 $(VCS_FLAGS) $(VCS_INCDIR) $(VCS_DEFINES) -f  sv.filelist
+
+
+dve:
+	dve -full64 -vpd vcdplus.vpd &
+
+
+clean:
+	rm -rf csrc simv simv.daidir stack.info*
+	rm -rf ucli.key vc_hdrs.h vcdplus.vpd run.log

testing/bsg_misc/bsg_alloc_wavefront/get_random.cpp

@@ -0,0 +1,9 @@
+#include <random>
+
+extern "C" int get_random_binary() {
+  //static std::random_device rd;
+  static std::mt19937 e(0);
+  static std::uniform_int_distribution<int> dis (0,1);
+  int rand = dis(e);
+  return rand;
+}

testing/bsg_misc/bsg_alloc_wavefront/sv.filelist

@@ -0,0 +1,9 @@
+testbench.sv
+get_random.cpp
+$BASEJUMP_STL_DIR/bsg_test/bsg_nonsynth_clock_gen.sv
+$BASEJUMP_STL_DIR/bsg_test/bsg_nonsynth_reset_gen.sv
+$BASEJUMP_STL_DIR/bsg_misc/bsg_alloc_wavefront.sv
+$BASEJUMP_STL_DIR/bsg_misc/bsg_cycle_counter.sv
+$BASEJUMP_STL_DIR/bsg_misc/bsg_transpose.sv
+$BASEJUMP_STL_DIR/bsg_misc/bsg_arb_round_robin.sv
+$BASEJUMP_STL_DIR/bsg_misc/bsg_scan.sv

testing/bsg_misc/bsg_alloc_wavefront/testbench.sv

@@ -0,0 +1,125 @@
+`include "bsg_defines.sv"
+
+
+module testbench();
+
+  // Clock gen and reset;
+  bit clk, reset;
+
+  bsg_nonsynth_clock_gen #(
+    .cycle_time_p(10)
+  ) cg0 (.o(clk)); 
+
+
+  bsg_nonsynth_reset_gen #(
+    .reset_cycles_lo_p(0)
+    ,.reset_cycles_hi_p(4)
+  ) rg0 (
+    .clk_i(clk)
+    ,.async_reset_o(reset)
+  );
+
+
+
+  // Parameters;
+  localparam width_p = 5;
+
+
+  // Random number DPI;
+  import "DPI-C" context function int get_random_binary();
+
+
+  // DUT;
+  logic [width_p-1:0][width_p-1:0] reqs_r, grants_lo;
+  logic yumi_li;
+
+  bsg_alloc_wavefront #(
+    .width_p(width_p)
+  ) DUT (
+    .clk_i(clk)
+    ,.reset_i(reset)
+
+    ,.reqs_i(reqs_r)
+    ,.grants_o(grants_lo)
+
+    ,.yumi_i(yumi_li)
+  );
+
+  assign yumi_li = 1'b1;
+
+  always_ff @ (posedge clk) begin
+    if (reset) begin
+      reqs_r <= '0;
+    end
+    else begin
+      for (integer i = 0; i < width_p; i++) begin
+        for (integer j = 0; j < width_p; j++) begin
+          reqs_r[i][j] <= get_random_binary();
+        end
+      end
+    end
+  end
+
+
+  // cycle counter;
+  integer ctr_r;
+  bsg_cycle_counter #(
+    .width_p(32)
+  ) cc0 (
+    .clk_i(clk)
+    ,.reset_i(reset)
+    ,.ctr_r_o(ctr_r)
+  );
+
+  initial begin
+    wait(ctr_r == 100000);
+    $finish();
+  end
+
+
+  // transpose grants_lo;
+  logic [width_p-1:0][width_p-1:0] grants_lo_tp;
+  bsg_transpose #(
+    .width_p(width_p)
+    ,.els_p(width_p)
+  ) tp0 (
+    .i(grants_lo)
+    ,.o(grants_lo_tp)
+  );
+
+
+  // assertion;;
+  always_ff @ (negedge clk) begin
+    if (~reset) begin
+      // Assert #1;
+      for (integer i = 0; i < width_p; i++) begin
+        for (integer j = 0; j < width_p; j++) begin
+          if (grants_lo[i][j]) begin
+            assert(reqs_r[i][j]) else $error("(%0d, %0d) grants=1, but req=0.", i, j);
+          end
+        end
+      end
+
+      // Assert #2;
+      for (integer i = 0; i < width_p; i++) begin
+        assert($countones(grants_lo[i]) < 2) else $error("Found more than one grant in row %d", i);
+      end
+
+      // Assert #3;
+      for (integer i = 0; i < width_p; i++) begin
+        assert($countones(grants_lo_tp[i]) < 2) else $error("Found more than one grant in column %d", i);
+      end
+
+      // Assert #4;
+      for (integer i = 0; i < width_p; i++) begin
+        for (integer j = 0; j < width_p; j++) begin
+          if (reqs_r[i][j] & ~grants_lo[i][j]) begin
+            assert ($countones(grants_lo[i] & ~(1'b1 << j)) > 0 || $countones(grants_lo_tp[j] & ~(1'b1 << i)) > 0) else $error("Req but no grant, but no col/row neighbor granted. (%d, %d)", i, j);
+          end
+        end
+      end
+    end
+  end
+
+
+endmodule