Add Vivado xsim DPI-C co-simulation backend for RogueTcpStream, RogueTcpMemory, and RogueSideBand

.gitignore

@@ -19,6 +19,7 @@ ruckus
 ruckus/
 build/
 sim_build*
+xsc.pb
 .coverage*
 
 # Local editor/agent state

axi/README.md

@@ -9,6 +9,6 @@ This tree contains reusable AXI-family RTL and wrappers. Top-level `axi/ruckus.t
 - `axi4/`: full AXI4 support blocks and adapters.
 - `bridge/`: bridges between AXI-family buses and SURF protocol records.
 - `dma/`: DMA register, descriptor, FIFO, and stream integration cores.
-- `simlink/`: simulator-link support and C/C++/VHDL pieces used by simulation flows.
+- `simlink/`: simulator-link support and C/C++/VHDL pieces used by simulation flows (GHDL, VCS, and Vivado xsim backends). See [simlink/README.md](simlink/README.md) for the Rogue TCP/SideBand co-simulation usage guide.
 
 Use existing package record types before adding flattened ports. Put durable adapter entities in `ip_integrator/` or `wrappers/`, and keep executable cocotb tests under `tests/axi/`.

axi/simlink/README.md

@@ -0,0 +1,71 @@
+# Simlink
+
+This directory holds three interchangeable Rogue co-simulation backends -- GHDL/VHPIDIRECT (`ghdl/`), Synopsys VCS/VHPI (`vcs/`), and Vivado xsim/DPI (`xsim/`) -- selected automatically by `ruckus.tcl` based on the active simulator. All three backends share the same `shared/` C cores and speak the same ZeroMQ wire protocol to a Rogue-side Python peer, so a testbench built against one backend behaves the same on any of the others.
+
+## Prerequisites
+
+- `libzmq >= 4.1.0` -- check with `pkg-config --modversion libzmq`.
+- Vivado simulator tools (`xsc`, `xvlog`, `xvhdl`, `xelab`, and `xsim`) for
+  the xsim backend.
+- A compatible Rogue or ZeroMQ peer for the selected Stream, Memory, or
+  SideBand wire protocol.
+
+## Running the Vivado xsim Co-Simulation
+
+An external target must provide a simulation top containing one or more
+`RogueTcpStream`, `RogueTcpMemory`, `RogueSideBand`, or corresponding SURF
+wrapper instances. It must drive clock/reset, assign a distinct two-port pair
+to every live instance, and provide a peer that implements the matching wire
+protocol. The first instance uses `portNum` and `portNum+1`; a subsequent
+instance must therefore start at least two ports higher.
+
+From a target using the standard ruckus simulation flow, run `make gui` or the
+target's xsim make target. `axi/simlink/ruckus.tcl` selects `xsim/`, the build
+creates the combined `RogueTcpDpi.so`, and elaboration binds it once with
+`-sv_lib RogueTcpDpi`. After reset is released, each instance prints its
+`Listening on ports N & N+1` message.
+
+The transport preserves the long-standing VCS/GHDL operating contract:
+connect the peer and keep it draining before HDL produces outbound messages.
+Simulator-thread receive is nonblocking, but send retains the existing
+synchronous ZeroMQ behavior across all three backends.
+
+## Checked-In xsim Example
+
+The repository's runnable example is the focused multi-instance regression:
+
+- `tests/axi/simlink/RogueXsimMultiTb.vhd` instantiates four Stream, two
+  Memory, and two SideBand models concurrently.
+- `tests/axi/simlink/test_RogueXsimMulti.py` builds the DPI library, checks the
+  generated DPI-C prototypes, compiles the mixed-language design, runs xsim,
+  and verifies duplicate-port rejection.
+
+The standalone DPI library and ABI check can be built with:
+
+```bash
+make -C axi/simlink/xsim all abi-check
+```
+
+Run it from the repository root in a Vivado-enabled shell:
+
+```bash
+./.venv/bin/python -m pytest -q -n 0 tests/axi/simlink/test_RogueXsimMulti.py
+```
+
+The test skips with an explicit reason when Vivado simulator tools are not on
+`PATH`. The protocol codecs and deterministic ZeroMQ peer used by the broader
+simlink regressions are in `tests/axi/simlink/rogue_tcp_peer.py`.
+
+## Troubleshooting
+
+**"libzmq package was not found"**
+If the Tcl console prints:
+```
+libzmq package was not found
+Please make sure that you have libzmq installed
+or have sourced the necessary rogue setup scripts
+```
+install libzmq (or source the Rogue setup scripts that put it on `PKG_CONFIG_PATH`) and re-run `make gui`.
+
+**Idle waveform, no data movement**
+If the console printed `Listening on ports N & N+1` but the waveform never shows activity, the peer has not connected. Confirm the driver script is running, targeting the same host (loopback `127.0.0.1`) and port pair as the module under test, and that push/pull directions are not swapped.

axi/simlink/ruckus.tcl

@@ -4,11 +4,36 @@ source $::env(RUCKUS_PROC_TCL)
 # Load Simulation
 loadSource -lib surf -sim_only -dir "$::DIR_PATH/tb"
 
-# Check if not GHDL
-if {![info exists ::env(GHDLFLAGS)]} {
-   # Include VHPI
-   loadSource -lib surf -sim_only -dir "$::DIR_PATH/vcs"
+# Select the simulator backend. Prefer the backend explicitly requested by the
+# ruckus make target (make xsim/gui -> xsim, make vcs -> vcs). Fall back to
+# environment sniffing for older ruckus. Note: sniffing VCS_VERSION alone is
+# unreliable because users commonly source both Vivado and VCS in one setup
+# script, so VCS_VERSION is set even during a Vivado xsim run.
+if {[info exists ::env(RUCKUS_SIM_BACKEND)]} {
+   set simBackend $::env(RUCKUS_SIM_BACKEND)
+} elseif {[info exists ::env(GHDLFLAGS)]} {
+   set simBackend "ghdl"
+} elseif {[info exists ::env(VCS_VERSION)]} {
+   set simBackend "vcs"
 } else {
-   # Exclude VHPI
-   loadSource -lib surf -sim_only -dir "$::DIR_PATH/ghdl"
+   set simBackend "xsim"
 }
+
+# When re-generating an existing Vivado project, purge sibling-backend sources
+# so switching backends doesn't leave duplicate RogueTcp* entities in sim_1.
+# Only remove when present, to avoid needless add/remove churn in the project.
+# Guard on VIVADO_VERSION because get_files/remove_files are Vivado-only; GHDL
+# re-analyzes from scratch and has no persistent project to clean.
+if {$::env(VIVADO_VERSION) > 0.0} {
+   foreach other {ghdl vcs xsim} {
+      if {${other} ne ${simBackend}} {
+         set staleFiles [get_files -quiet [file normalize "$::DIR_PATH/${other}/*"]]
+         if {[llength ${staleFiles}] > 0} {
+            remove_files -quiet ${staleFiles}
+         }
+      }
+   }
+}
+
+# Load the selected backend
+loadSource -lib surf -sim_only -dir "$::DIR_PATH/${simBackend}"

axi/simlink/tb/RogueTcpStreamWrap.vhd

@@ -133,7 +133,7 @@ begin
    end generate;
 
    -- Channels
-   U_ChanGen : for i in 0 to CHAN_COUNT_C-1 generate
+   GEN_CHAN : for i in 0 to CHAN_COUNT_C-1 generate
       ------------------
       -- Inbound Resizer
       ------------------

axi/simlink/xsim/Makefile

@@ -0,0 +1,67 @@
+##############################################################################
+## This file is part of 'SLAC Firmware Standard Library'.
+## It is subject to the license terms in the LICENSE.txt file found in the
+## top-level directory of this distribution and at:
+##    https://confluence.slac.stanford.edu/display/ppareg/LICENSE.html.
+## No part of 'SLAC Firmware Standard Library', including this file,
+## may be copied, modified, propagated, or distributed except according to
+## the terms contained in the LICENSE.txt file.
+##############################################################################
+# xsc-based build (Vivado xsim DPI-C), re-targeted from ghdl/Makefile's
+# gcc -shared -fPIC + pkg-config libzmq pattern to the xsc two-step compile/
+# link flow. Builds the combined RogueTcpDpi.so from every module's DPI-C
+# adapter plus the shared per-instance ownership manager; a single
+# "-sv_lib RogueTcpDpi" binds all of them. The file is named RogueTcpDpi.so
+# (no "lib" prefix): xelab's "-sv_lib
+# RogueTcpDpi" resolves the DPI library as <name>.so, not lib<name>.so
+# (per UG900). xsc stages its compiled object under its own implicit
+# ./xsim.dir/work/xsc/ directory (no BUILD_DIR indirection like GHDL/VCS use).
+##############################################################################
+
+CC     := xsc
+ELAB   := xelab
+# -I../shared resolves the shared RogueTcp*Core.h headers that every backend
+# includes; xsc's underlying gcc searches the including file's own dir
+# first, so the xsim/ RogueTcp*.h still take precedence. svdpi.h is
+# auto-found by xsc (adds $XILINX_VIVADO/data/xsim/include automatically).
+CFLAGS := -I../shared $(shell pkg-config --cflags libzmq)
+# Vivado <= 2024.1 bundles a gcc-9.3.0 whose link driver invokes its own
+# binutils via -B and does not search the host multiarch lib dir, so the
+# RogueTcpDpi.so link fails with "cannot find crti.o / -lzmq / -lm". Point both
+# the startfile search (-B, for crt*.o) and the library search (-L) at the
+# active gcc's lib dir, derived portably from `gcc -print-file-name=crti.o`
+# (resolves to /usr/lib/x86_64-linux-gnu on Debian/Ubuntu, /usr/lib64 on RHEL).
+# Harmless on Vivado >= 2024.2, whose xsc already resolves these.
+MULTIARCH_DIR := $(dir $(shell gcc -print-file-name=crti.o))
+LFLAGS := $(shell pkg-config --libs libzmq) -B$(MULTIARCH_DIR) -L$(MULTIARCH_DIR)
+
+LIB := RogueTcpDpi.so
+SOURCES := RogueDpiInstance.c RogueTcpStream.c RogueTcpMemory.c RogueSideBand.c
+HEADERS := RogueDpiInstance.h RogueTcpStream.h RogueTcpMemory.h RogueSideBand.h \
+           ../shared/RogueTcpStreamCore.h ../shared/RogueTcpMemoryCore.h \
+           ../shared/RogueSideBandCore.h
+SV_SOURCES := RogueTcpStreamDpi.sv RogueTcpMemoryDpi.sv RogueSideBandDpi.sv
+ABI_HEADER := xsim.dir/RogueTcpDpi.generated.h
+
+all: $(LIB)
+
+$(LIB): $(SOURCES) $(HEADERS)
+	$(CC) -c RogueDpiInstance.c -gcc_compile_options "$(CFLAGS)"
+	$(CC) -c RogueTcpStream.c -gcc_compile_options "$(CFLAGS)"
+	$(CC) -c RogueTcpMemory.c -gcc_compile_options "$(CFLAGS)"
+	$(CC) -c RogueSideBand.c -gcc_compile_options "$(CFLAGS)"
+	$(CC) --shared -o $(LIB) -gcc_link_options "$(LFLAGS)"
+
+$(ABI_HEADER): $(SV_SOURCES)
+	mkdir -p $(dir $@)
+	$(ELAB) -dpiheader $@ -svlog $(SV_SOURCES)
+
+abi-check: $(ABI_HEADER) $(SOURCES) $(HEADERS)
+	$(CC) -c RogueTcpStream.c -gcc_compile_options "$(CFLAGS) -include $(abspath $(ABI_HEADER))"
+	$(CC) -c RogueTcpMemory.c -gcc_compile_options "$(CFLAGS) -include $(abspath $(ABI_HEADER))"
+	$(CC) -c RogueSideBand.c -gcc_compile_options "$(CFLAGS) -include $(abspath $(ABI_HEADER))"
+
+clean:
+	rm -rf xsim.dir xsc.pb xsc.log xelab.pb xelab.log xelab.jou $(LIB)
+
+.PHONY: all abi-check clean