target/sim: Add VCS simulation flow (#163)

* vip: Various fixes for VCS, bump AXI

* cheshire_pkg: Replace parameter by variables inside function

* vcs: Add first version of vcs scripts

* ci: Add vcs to CI

* sim: Some cleanup

* docs: Document simulation using VCS

* Bender.yml: Update to newest AXI version

* make: Use Bender flags variable for VCS compile script

---------

Co-authored-by: Paul Scheffler <paulsc@iis.ee.ethz.ch>

Author: CyrilKoe

.gitignore

@@ -38,6 +38,16 @@ target/sim/vsim/transcript
 target/sim/vsim/vsim.wlf
 target/sim/vsim/work/
 
+# VCS generated files
+target/sim/vcs/compile.*.sh
+target/sim/vcs/*.log
+target/sim/vcs/AN.DB
+target/sim/vcs/simv*
+target/sim/vcs/csrc
+target/sim/vcs/ucli.key
+target/sim/vcs/work*
+target/sim/vcs/vc_hdrs.h
+
 # Xilinx generated files
 target/xilinx/build
 target/xilinx/out

Bender.lock

@@ -15,8 +15,8 @@ packages:
     - apb
     - register_interface
   axi:
-    revision: ac5deb3ff086aa34b168f392c051e92603d6c0e2
-    version: 0.39.2
+    revision: 39f5f2d51c5e524f6fc5cf8b6e901f7dcc5622d7
+    version: 0.39.6
     source:
       Git: https://github.com/pulp-platform/axi.git
     dependencies:

Bender.yml

@@ -13,7 +13,7 @@ package:
 
 dependencies:
   apb_uart:                 { git: "https://github.com/pulp-platform/apb_uart.git",               version: 0.2.1  }
-  axi:                      { git: "https://github.com/pulp-platform/axi.git",                    version: 0.39.2 }
+  axi:                      { git: "https://github.com/pulp-platform/axi.git",                    version: 0.39.6 }
   axi_llc:                  { git: "https://github.com/pulp-platform/axi_llc.git",                version: 0.2.1  }
   axi_riscv_atomics:        { git: "https://github.com/pulp-platform/axi_riscv_atomics.git",      version: 0.8.2  }
   axi_rt:                   { git: "https://github.com/pulp-platform/axi_rt.git",                 version: 0.0.0-alpha.9 }

cheshire.mk

@@ -7,11 +7,13 @@
 # Paul Scheffler <paulsc@iis.ee.ethz.ch>
 
 BENDER ?= bender
+VLOGAN ?= vlogan
 
 # Caution: Questasim requires this to point to the *actual* compiler install path
 CXX_PATH := $(shell which $(CXX))
 
-VLOG_ARGS ?= -suppress 2583 -suppress 13314 -timescale 1ns/1ps
+VLOG_ARGS   ?= -suppress 2583 -suppress 13314 -timescale 1ns/1ps
+VLOGAN_ARGS ?= -kdb -nc -assert svaext +v2k -timescale=1ns/1ps
 
 # Common Bender flags for Cheshire RTL
 CHS_BENDER_RTL_FLAGS ?= -t rtl -t cva6 -t cv64a6_imafdcsclic_sv39
@@ -61,7 +63,7 @@ chs-clean-deps:
 ######################
 
 CHS_NONFREE_REMOTE ?= git@iis-git.ee.ethz.ch:pulp-restricted/cheshire-nonfree.git
-CHS_NONFREE_COMMIT ?= 99e58ec
+CHS_NONFREE_COMMIT ?= 99aa8d9
 
 CHS_PHONY += chs-nonfree-init
 chs-nonfree-init:
@@ -149,6 +151,10 @@ $(CHS_ROOT)/target/sim/vsim/compile.cheshire_soc.tcl: $(CHS_ROOT)/Bender.yml
 	$(BENDER) script vsim -t sim -t test $(CHS_BENDER_RTL_FLAGS) --vlog-arg="$(VLOG_ARGS)" > $@
 	echo 'vlog "$(realpath $(CHS_ROOT))/target/sim/src/elfloader.cpp" -ccflags "-std=c++11" -cpppath "$(CXX_PATH)"' >> $@
 
+$(CHS_ROOT)/target/sim/vcs/compile.cheshire_soc.sh: $(CHS_ROOT)/Bender.yml
+	$(BENDER) script vcs -t sim -t test $(CHS_BENDER_RTL_FLAGS) --vlog-arg="$(VLOGAN_ARGS)" --vlogan-bin="$(VLOGAN)" > $@
+	chmod +x $@
+
 .PRECIOUS: $(CHS_ROOT)/target/sim/models
 $(CHS_ROOT)/target/sim/models:
 	mkdir -p $@
@@ -167,6 +173,7 @@ $(CHS_ROOT)/target/sim/models/24FC1025.v: $(CHS_ROOT)/Bender.yml | $(CHS_ROOT)/t
 CHS_SIM_ALL += $(CHS_ROOT)/target/sim/models/s25fs512s.v
 CHS_SIM_ALL += $(CHS_ROOT)/target/sim/models/24FC1025.v
 CHS_SIM_ALL += $(CHS_ROOT)/target/sim/vsim/compile.cheshire_soc.tcl
+CHS_SIM_ALL += $(CHS_ROOT)/target/sim/vcs/compile.cheshire_soc.sh
 
 ###########
 # DRAMSys #

docs/tg/sim.md

@@ -5,6 +5,7 @@ This page describes how to simulate Cheshire to *execute baremetal programs*. Pl
 We currently provide working setups for:
 
 - Questa Advanced Simulator (QuestaSim) `>= 2022.3`
+- VCS `>= 2024.09`
 
 We plan on supporting more simulators in the future. If your situation requires it, simulating Cheshire on other setups should be straightforward.
 
@@ -21,21 +22,21 @@ We provide a SystemVerilog testbench for `cheshire_soc` running baremetal progra
 
 Preloading boot modes expect an ELF executable to be passed through `BINARY`, while autonomous boot modes expect a disk image (GPT formatted or raw code) to be passed through `IMAGE`. For more information on how to build software for Cheshire and its boot process, see [Software Stack](../um/sw.md).
 
-The `SELCFG` environment variable selects the Cheshire configuration used in simulations. Possible configurations are specified in the `tb_cheshire_pkg` package. If not set or set to `0`, the default configuration is selected.
+The `SELCFG` variable selects the Cheshire configuration used in simulations. Possible configurations are specified in the `tb_cheshire_pkg` package. If not set or set to `0`, the default configuration is selected.
 
 | `SELCFG` | Configuration in (`tb_cheshire_pkg`)      |
 | -------- | ----------------------------------------- |
 | 0        | Default configuration from `cheshire_pkg` |
 | 1        | AXI-RT-enabled configuration              |
 | 2        | CLIC-enabled configuration                |
 
-The `USE_DRAMSYS` environment variable controls whether simulations are linked against and use DRAMSys for DRAM simulation. Note that before starting a simulation using DRAMSys, it must be built with `make chs-dramsys-all` first.
+The `USE_DRAMSYS` variable controls whether simulations are linked against and use DRAMSys for DRAM simulation. Note that before starting a simulation using DRAMSys, it must be built with `make chs-dramsys-all` first.
 
 For simulation of Cheshire in other designs, we provide the module `cheshire_vip` encapsulating all verification IPs and their interfaces. For details, see [Verifying Cheshire In-System](integr.md#verifying-cheshire-in-system).
 
 ## QuestaSim
 
-After building Cheshire, start QuestaSim in `target/sim/vsim` and run:
+Variables are read from QuestaSim's Tcl environment. After building Cheshire, start QuestaSim in `target/sim/vsim` and run:
 
 ```tcl
 # Preload `helloworld.spm.elf` through serial link
@@ -52,3 +53,22 @@ run -all
 ```
 
 The design needs to be recompiled only when hardware is changed. The simulation can be restarted by re-sourcing `start.cheshire_soc.tcl`, allowing binary (or image) and load method changes beforehand.
+
+## VCS
+
+Variables are read from your shell environment. After building Cheshire, start a POSIX-compliant shell in `target/sim/vcs` and run:
+
+```sh
+# Preload `helloworld.spm.elf` through serial link
+export BINARY="../../../sw/tests/helloworld.spm.elf"
+export BOOTMODE=0
+export PRELMODE=1
+
+# Compile design
+./compile.cheshire_soc.sh
+
+# Start and run simulation
+./start.cheshire_soc.sh
+```
+
+The design needs to be recompiled only when hardware is changed. The simulation can be run repeatedly using `start.cheshire_soc.sh`, allowing binary (or image) and load method changes beforehand.

hw/cheshire_pkg.sv

@@ -463,7 +463,7 @@ package cheshire_pkg;
 
   // Choose static colocation of IDs based on how heavily used and/or critical they are
   function automatic cva6_id_map_t gen_cva6_id_map(cheshire_cfg_t cfg);
-    localparam int unsigned DefaultMapEntry[2] = '{0, 0};
+    int unsigned DefaultMapEntry[2] = '{0, 0};
     case (cfg.AxiMstIdWidth)
       // Provide exclusive ID to I-cache to prevent fetch blocking
       1: return '{'{Cva6IdBypMmu, 0}, '{Cva6IdBypLoad, 0}, '{Cva6IdBypAccel, 0}, '{Cva6IdBypStore, 0},

target/sim/src/vip_cheshire_soc.sv

@@ -228,7 +228,7 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
   assign jtag.tdo     = jtag_tdo;
 
   initial begin
-    @(negedge rst_n);
+    wait (!rst_n);
     jtag_dbg.reset_master();
   end
 
@@ -469,6 +469,7 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
   initial begin
     static byte_bt uart_read_buf [$];
     byte_bt bite;
+    string line;
     wait_for_reset();
     forever begin
       uart_read_byte(bite);
@@ -477,7 +478,8 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
         uart_boot_ena = 0;
       end else if (bite == "\n") begin
         if (uart_read_buf.size() > 0) begin
-          $display("[UART] %s", {>>8{uart_read_buf}});
+          line = {>>8{uart_read_buf}};
+          $display("[UART] %s", line);
           uart_read_buf.delete();
         end else begin
           $display("[UART]");
@@ -648,7 +650,7 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
     .AXI_DATA_WIDTH ( DutCfg.AxiDataWidth  ),
     .AXI_ID_WIDTH   ( DutCfg.AxiMstIdWidth ),
     .AXI_USER_WIDTH ( DutCfg.AxiUserWidth  )
-  ) slink_mst_ext(), slink_mst_vip(), slink_mst();
+  ) slink_mst_ext(), slink_mst_vip(), slink_mst(), slink_slv_mux[1:0]();
 
   AXI_BUS #(
     .AXI_ADDR_WIDTH ( DutCfg.AddrWidth       ),
@@ -666,6 +668,9 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
     .clk_i  ( clk )
   );
 
+  `AXI_ASSIGN (slink_slv_mux[0], slink_mst_ext)
+  `AXI_ASSIGN (slink_slv_mux[1], slink_mst_vip)
+
   // Multiplex internal and external AXI requests
   axi_mux_intf #(
     .SLV_AXI_ID_WIDTH ( DutCfg.AxiMstIdWidth   ),
@@ -678,8 +683,8 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
     .clk_i  ( clk ),
     .rst_ni ( rst_n ),
     .test_i ( test_mode ),
-    .slv    ( '{slink_mst_vip, slink_mst_ext} ),
-    .mst    ( slink_mst_mux  )
+    .slv    ( slink_slv_mux ),
+    .mst    ( slink_mst_mux )
   );
 
   // Serialize away added AXI index bits
@@ -785,7 +790,7 @@ module vip_cheshire_soc import cheshire_pkg::*; #(
   slink_axi_driver_t slink_axi_driver = new (slink_mst_vip_dv);
 
   initial begin
-    @(negedge rst_n);
+    wait (!rst_n);
     slink_axi_driver.reset_master();
   end
 
@@ -951,20 +956,20 @@ endmodule
 
 module vip_cheshire_soc_tristate import cheshire_pkg::*; (
   // I2C pad IO
-  output logic  i2c_sda_i,
-  input  logic  i2c_sda_o,
-  input  logic  i2c_sda_en,
-  output logic  i2c_scl_i,
-  input  logic  i2c_scl_o,
-  input  logic  i2c_scl_en,
+  output wire i2c_sda_i,
+  input  wire i2c_sda_o,
+  input  wire i2c_sda_en,
+  output wire i2c_scl_i,
+  input  wire i2c_scl_o,
+  input  wire i2c_scl_en,
   // SPI host pad IO
-  input  logic                  spih_sck_o,
-  input  logic                  spih_sck_en,
-  input  logic [SpihNumCs-1:0]  spih_csb_o,
-  input  logic [SpihNumCs-1:0]  spih_csb_en,
-  output logic [ 3:0]           spih_sd_i,
-  input  logic [ 3:0]           spih_sd_o,
-  input  logic [ 3:0]           spih_sd_en,
+  input  wire                  spih_sck_o,
+  input  wire                  spih_sck_en,
+  input  wire [SpihNumCs-1:0]  spih_csb_o,
+  input  wire [SpihNumCs-1:0]  spih_csb_en,
+  output wire [ 3:0]           spih_sd_i,
+  input  wire [ 3:0]           spih_sd_o,
+  input  wire [ 3:0]           spih_sd_en,
   // I2C wires
   inout  wire i2c_sda,
   inout  wire i2c_scl,

target/sim/vcs/start.cheshire_soc.sh

@@ -0,0 +1,57 @@
+# #!/usr/bin/env bash
+# Copyright 2022 ETH Zurich and University of Bologna.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Cyril Koenig <cykoenig@iis.ee.ethz.ch>
+
+TESTBENCH=tb_cheshire_soc
+
+# Set full path to c++ compiler.
+if [ -z "${CXX_PATH}" ]; then
+    if [ -z "${CXX}" ]; then
+        CXX="g++"
+    fi
+    CXX_PATH=`which ${CXX}`
+fi
+
+# Set default VCS binary
+[[ -z "${VERDI_VERSION}" ]] && VERDI_VERSION=""
+[[ -z "${VCS_VERSION}" ]]   && VCS_VERSION=""
+[[ -z "${VCS_BIN}" ]]       && VCS_BIN="${VCS_VERSION} vcs"
+
+flags="-full64 -kdb "
+# Set default to fast simulation flags.
+if [ -z "${VCSARGS}" ]; then
+    # Use -debug_access+all for waveform debugging
+    flags+="-O2 -debug_access=r -debug_region=1,${TESTBENCH} "
+fi
+
+flags+="-cpp ${CXX_PATH} "
+[[ -n "${SELCFG}" ]]   && flags+="-pvalue+SelectedCfg=${SELCFG} "
+
+pargs=""
+[[ -n "${BOOTMODE}" ]] && pargs+="+BOOTMODE=${BOOTMODE} "
+[[ -n "${PRELMODE}" ]] && pargs+="+PRELMODE=${PRELMODE} "
+[[ -n "${BINARY}" ]]   && pargs+="+BINARY=${BINARY} "
+[[ -n "${IMAGE}" ]]    && pargs+="+IMAGE=${IMAGE} "
+
+# DRAMSys
+if [ -n "${USE_DRAMSYS}" ]; then
+    flags+="-pvalue UseDramSys=${USE_DRAMSYS} "
+    if [[ "${USE_DRAMSYS}" == 1 ]]; then
+        DRAMSYS_ROOT="../dramsys"
+        DRAMSYS_LIB="${DRAMSYS_ROOT}/build/lib"
+        pargs+="+DRAMSYS_RES=${DRAMSYS_ROOT}/configs "
+        pargs+="-sv_lib ${DRAMSYS_LIB}/libDRAMSys_Simulator "
+    fi
+fi
+
+COLOR_NC='\e[0m'
+COLOR_BLUE='\e[0;34m'
+
+${VCS_BIN} ${flags} ../src/elfloader.cpp ${TESTBENCH} | tee elaborate.log
+
+# Start simulation
+printf ${COLOR_BLUE}"${VCS_VERSION} ${VERDI_VERSION} ./simv ${pargs}"${COLOR_NC}"\n"
+${VCS_VERSION} ${VERDI_VERSION} ./simv ${pargs} | tee simulate.log