Rework how tracer is instantiated and called

This change is slighly painful, but a necessary cleanup around the
tracer.

- We now provide a separate core file for the tracer, called
  "ibex_tracer.core" (in line with "ibex_tracer.sv"). The core is called
  "lowrisc:ibex:ibex_tracer".
- The toplevel wrapper with tracing enabled got renamed to
  "ibex_core_tracing.sv", and the core file is correspondingly called
  "ibex_core_tracing.core. The core in it is called
  "lowrisc:ibex:ibex_core_tracing".
- Finally to keep symmetry, the toplevel of Ibex itself got renamed in
  the core file from "lowrisc:ibex:ibex" to "lowrisc:ibex:ibex_core".
  This ensures that we have the same name for the core file, the source
  entry point, and the core name.

IMPORTANT NOTE:
If you apply this change and use fusesoc, you need to adjust the name of
the core dependency from "lowrisc:ibex:ibex" to
"lowrisc:ibex:ibex_core".

doc/tracer.rst

@@ -4,7 +4,7 @@ Tracer
 ======
 
 The module ``ibex_tracer`` can be used to create a log of the executed instructions.
-It is used by ``ibex_core_tracer`` which forwards the signals added by :ref:`rvfi` as an input for the tracer.
+It is used by ``ibex_core_tracing`` which forwards the signals added by :ref:`rvfi` as an input for the tracer.
 
 .. note::
 

dv/uvm/ibex_dv.f

@@ -25,7 +25,7 @@ ${PRJ_DIR}/ibex/rtl/ibex_prefetch_buffer.sv
 ${PRJ_DIR}/ibex/rtl/ibex_fetch_fifo.sv
 ${PRJ_DIR}/ibex/rtl/ibex_register_file_ff.sv
 ${PRJ_DIR}/ibex/rtl/ibex_core.sv
-${PRJ_DIR}/ibex/rtl/ibex_core_tracer.sv
+${PRJ_DIR}/ibex/rtl/ibex_core_tracing.sv
 
 // Core DV files
 +incdir+${PRJ_DIR}/ibex/dv/uvm/env

dv/uvm/tb/core_ibex_tb_top.sv

@@ -14,7 +14,7 @@ module core_ibex_tb_top;
   clk_if ibex_clk_if(.clk(clk));
 
   // TODO(taliu) Resolve the tied-off ports
-  ibex_core_tracer #(.DmHaltAddr(`BOOT_ADDR + 'h40),
+  ibex_core_tracing #(.DmHaltAddr(`BOOT_ADDR + 'h40),
                       .DmExceptionAddr(`BOOT_ADDR + 'h44)
   ) dut (
     .clk_i(clk),

examples/fpga/artya7-100/top_artya7_100.core

@@ -7,7 +7,7 @@ description: "Ibex example toplevel for the Arty A7-100 board"
 filesets:
   files_rtl_artya7:
     depend:
-      - lowrisc:ibex:ibex
+      - lowrisc:ibex:ibex_core
     files:
       - rtl/top_artya7_100.sv
       - rtl/ram_1p.sv

examples/sim/README.md

@@ -1,8 +1,8 @@
-# Ibex tracer simulation example
+# Example: Ibex with enabled instruction tracing for simulation
 
 ## Overview
 
-This examples shows the usage of the module `ibex_core_tracer` which forwards
+This examples shows the usage of the module `ibex_core_tracing` which forwards
 all port signals to the `ibex_core` and a subset of signals to `ibex_tracer`.
 The tracer will create a file with a stream of executed instructions.
 
@@ -20,7 +20,7 @@ export MODEL_TECH=/path/to/modelsim/bin
 Run the following command in the top level directory.
 
 ```
-fusesoc --cores-root=. run --target=sim lowrisc:ibex:top_tracer_sim
+fusesoc --cores-root=. run --target=sim lowrisc:ibex:top_tracing_sim
 ```
 
-The trace output can be found in `build/lowrisc_ibex_top_tracer_sim_0.1/sim-modelsim/trace_core_00_0.log`.
+The trace output can be found in `build/lowrisc_ibex_top_tracing_sim_0.1/sim-modelsim/trace_core_00_0.log`.

examples/sim/tb/ibex_tracing_tb.sv

@@ -2,10 +2,10 @@
 // Licensed under the Apache License, Version 2.0, see LICENSE for details.
 // SPDX-License-Identifier: Apache-2.0
 //
-// Sample testbench for Ibex tracer
+// Sample testbench for Ibex with tracing enabled
 // The `nop` instruction is the only input
 
-module ibex_tracer_tb;
+module ibex_tracing_tb;
   logic         clk          = 1'b0;
   logic         rst_n        = 1'b0;
   logic [31:0]  instr_rdata  = 32'h00000013;
@@ -70,7 +70,7 @@ module ibex_tracer_tb;
     #10ns  instr_rdata  = 32'h0000000f;
   end
 
-  ibex_core_tracer ibex_i (
+  ibex_core_tracing ibex_i (
     .clk_i                  (clk),
     .rst_ni                 (rst_n),
 
@@ -108,29 +108,6 @@ module ibex_tracer_tb;
     // Debug Interface
     .debug_req_i            (1'b0),
 
-    // RISC-V Formal Interface
-    .rvfi_valid             (),
-    .rvfi_order             (),
-    .rvfi_insn              (),
-    .rvfi_insn_uncompressed (),
-    .rvfi_trap              (),
-    .rvfi_halt              (),
-    .rvfi_intr              (),
-    .rvfi_mode              (),
-    .rvfi_rs1_addr          (),
-    .rvfi_rs2_addr          (),
-    .rvfi_rs1_rdata         (),
-    .rvfi_rs2_rdata         (),
-    .rvfi_rd_addr           (),
-    .rvfi_rd_wdata          (),
-    .rvfi_pc_rdata          (),
-    .rvfi_pc_wdata          (),
-    .rvfi_mem_addr          (),
-    .rvfi_mem_rmask         (),
-    .rvfi_mem_wmask         (),
-    .rvfi_mem_rdata         (),
-    .rvfi_mem_wdata         (),
-
     // CPU Control Signals
     .fetch_enable_i         (1'b1)
   );

examples/sim/top_tracing_sim.core

@@ -2,15 +2,15 @@ CAPI=2:
 # Copyright lowRISC contributors.
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0
-name: "lowrisc:ibex:top_tracer_sim:0.1"
+name: "lowrisc:ibex:top_tracing_sim:0.1"
-description: "Ibex tracer example for modelsim"
+description: "Ibex with tracing enabled (ModelSim only right now)"
 filesets:
   files_tb:
     depend:
-      - lowrisc:ibex:tracer
+      - lowrisc:ibex:ibex_core_tracing
     files:
       - rtl/prim_clock_gating.sv
-      - tb/ibex_tracer_tb.sv
+      - tb/ibex_tracing_tb.sv
     file_type: systemVerilogSource
 
 targets:
@@ -19,7 +19,7 @@ targets:
     filesets:
       - files_tb
     toplevel:
-      - ibex_tracer_tb
+      - ibex_tracing_tb
     tools:
       modelsim:
         vlog_options: [-timescale=1ns/1ns]

ibex_core.core

@@ -2,7 +2,7 @@ CAPI=2:
 # Copyright lowRISC contributors.
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0
-name: "lowrisc:ibex:ibex:0.1"
+name: "lowrisc:ibex:ibex_core:0.1"
 description: "CPU core with 2 stage pipeline implementing the RV32IMC_Zicsr ISA"
 filesets:
   files_rtl:
@@ -29,6 +29,11 @@ filesets:
       - rtl/ibex_core.sv
     file_type: systemVerilogSource
 
+parameters:
+  RVFI:
+    datatype: bool
+    paramtype: vlogdefine
+
 targets:
   default:
     filesets:

ibex_core_tracing.core

@@ -0,0 +1,28 @@
+CAPI=2:
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+name: "lowrisc:ibex:ibex_core_tracing:0.1"
+description: "Ibex CPU core with tracing enabled"
+filesets:
+  files_rtl:
+    depend:
+      - lowrisc:ibex:ibex_core
+      - lowrisc:ibex:ibex_tracer
+    files:
+      - rtl/ibex_core_tracing.sv
+    file_type: systemVerilogSource
+
+parameters:
+  # The tracer uses the RISC-V Formal Interface (RVFI) to collect trace signals.
+  RVFI:
+    datatype: bool
+    paramtype: vlogdefine
+    default: true
+
+targets:
+  default:
+    filesets:
+      - files_rtl
+    parameters:
+      - RVFI=true

ibex_tracer.core

@@ -2,27 +2,16 @@ CAPI=2:
 # Copyright lowRISC contributors.
 # Licensed under the Apache License, Version 2.0, see LICENSE for details.
 # SPDX-License-Identifier: Apache-2.0
-name: "lowrisc:ibex:tracer:0.1"
+name: "lowrisc:ibex:ibex_tracer:0.1"
-description: "core_ibex_tracer"
+description: "Tracer for use with Ibex using the RVFI interface"
 filesets:
   files_rtl:
-    depend:
-      - lowrisc:ibex:ibex
     files:
       - rtl/ibex_tracer_pkg.sv
       - rtl/ibex_tracer.sv
-      - rtl/ibex_core_tracer.sv
     file_type: systemVerilogSource
 
-parameters:
-  RVFI:
-    datatype: bool
-    paramtype: vlogdefine
-    description: Enable RVFI signals for tracing
-
 targets:
   default:
     filesets:
       - files_rtl
-    parameters:
-      - RVFI=true

rtl/ibex_core_tracing.sv

@@ -3,13 +3,10 @@
 // SPDX-License-Identifier: Apache-2.0
 
 
-// ibex_tracer relies on the signals from the RISC-V Formal Interface
-`define RVFI
-
 /**
  * Top level module of the ibex RISC-V core with tracing enabled
  */
-module ibex_core_tracer #(
+module ibex_core_tracing #(
     parameter int unsigned MHPMCounterNum   = 8,
     parameter int unsigned MHPMCounterWidth = 40,
     parameter bit RV32E                     = 0,
@@ -55,33 +52,6 @@ module ibex_core_tracer #(
     // Debug Interface
     input  logic        debug_req_i,
 
-    // RISC-V Formal Interface
-    // Does not comply with the coding standards of _i/_o suffixes, but follows
-    // the convention of RISC-V Formal Interface Specification.
-`ifdef RVFI
-    output logic        rvfi_valid,
-    output logic [63:0] rvfi_order,
-    output logic [31:0] rvfi_insn,
-    output logic [31:0] rvfi_insn_uncompressed,
-    output logic        rvfi_trap,
-    output logic        rvfi_halt,
-    output logic        rvfi_intr,
-    output logic [ 1:0] rvfi_mode,
-    output logic [ 4:0] rvfi_rs1_addr,
-    output logic [ 4:0] rvfi_rs2_addr,
-    output logic [31:0] rvfi_rs1_rdata,
-    output logic [31:0] rvfi_rs2_rdata,
-    output logic [ 4:0] rvfi_rd_addr,
-    output logic [31:0] rvfi_rd_wdata,
-    output logic [31:0] rvfi_pc_rdata,
-    output logic [31:0] rvfi_pc_wdata,
-    output logic [31:0] rvfi_mem_addr,
-    output logic [ 3:0] rvfi_mem_rmask,
-    output logic [ 3:0] rvfi_mem_wmask,
-    output logic [31:0] rvfi_mem_rdata,
-    output logic [31:0] rvfi_mem_wdata,
-`endif
-
     // CPU Control Signals
     input  logic        fetch_enable_i
 
@@ -89,6 +59,33 @@ module ibex_core_tracer #(
 
   import ibex_pkg::*;
 
+  // ibex_tracer relies on the signals from the RISC-V Formal Interface
+  `ifndef RVFI
+    Fatal error: RVFI needs to be defined globally.
+  `endif
+
+  logic        rvfi_valid;
+  logic [63:0] rvfi_order;
+  logic [31:0] rvfi_insn;
+  logic [31:0] rvfi_insn_uncompressed;
+  logic        rvfi_trap;
+  logic        rvfi_halt;
+  logic        rvfi_intr;
+  logic [ 1:0] rvfi_mode;
+  logic [ 4:0] rvfi_rs1_addr;
+  logic [ 4:0] rvfi_rs2_addr;
+  logic [31:0] rvfi_rs1_rdata;
+  logic [31:0] rvfi_rs2_rdata;
+  logic [ 4:0] rvfi_rd_addr;
+  logic [31:0] rvfi_rd_wdata;
+  logic [31:0] rvfi_pc_rdata;
+  logic [31:0] rvfi_pc_wdata;
+  logic [31:0] rvfi_mem_addr;
+  logic [ 3:0] rvfi_mem_rmask;
+  logic [ 3:0] rvfi_mem_wmask;
+  logic [31:0] rvfi_mem_rdata;
+  logic [31:0] rvfi_mem_wdata;
+
   ibex_core #(
     .MHPMCounterNum(MHPMCounterNum),
     .MHPMCounterWidth(MHPMCounterWidth),
@@ -129,7 +126,6 @@ module ibex_core_tracer #(
 
     .debug_req_i,
 
-`ifdef RVFI
     .rvfi_valid,
     .rvfi_order,
     .rvfi_insn,
@@ -151,14 +147,13 @@ module ibex_core_tracer #(
     .rvfi_mem_wmask,
     .rvfi_mem_rdata,
     .rvfi_mem_wdata,
-`endif
 
     .fetch_enable_i
   );
 
 
 `ifndef VERILATOR
-  ibex_tracer ibex_tracer_i (
+  ibex_tracer u_ibex_tracer (
       .clk_i            ( clk_i                  ),
       .rst_ni           ( rst_ni                 ),
 
@@ -177,6 +172,8 @@ module ibex_core_tracer #(
       .ex_data_wdata_i  ( rvfi_mem_wdata         ),
       .ex_data_rdata_i  ( rvfi_mem_rdata         )
   );
-`endif // VERILATOR
+`else
+    // ibex_tracer uses language constructs which Verilator doesn't understand.
+`endif
 
 endmodule