[make] Add CS Register testbench targets

New targets to build and run the testbench.
Minor cleanup for parallel make runs.

Makefile

@@ -7,7 +7,8 @@ help:
 	@echo "or how to set-up the different environments."
 
 # Use a parallel run (make -j N) for a faster build
-build-all: build-riscv-compliance build-simple-system build-arty
+build-all: build-riscv-compliance build-simple-system build-arty \
+      build-csr-test
 
 
 # RISC-V compliance
@@ -31,13 +32,13 @@ sw-simple-hello: $(simple-system-program)
 
 .PHONY: $(simple-system-program)
 $(simple-system-program):
-	make -C examples/sw/simple_system/hello_test
+	cd examples/sw/simple_system/hello_test && $(MAKE)
 
 Vibex_simple_system = \
       build/lowrisc_ibex_ibex_simple_system_0/sim-verilator/Vibex_simple_system
 $(Vibex_simple_system):
 	@echo "$@ not found"
-	@echo "Run \"make build-simple-system\" to created the dependency"
+	@echo "Run \"make build-simple-system\" to create the dependency"
 	@false
 
 run-simple-system: sw-simple-hello | $(Vibex_simple_system)
@@ -54,7 +55,7 @@ sw-led: $(arty-sw-program)
 
 .PHONY: $(arty-sw-program)
 $(arty-sw-program):
-	make -C examples/sw/led
+	cd examples/sw/led && $(MAKE)
 
 build-arty: sw-led
 	fusesoc --cores-root=. run --target=synth --setup --build \
@@ -69,3 +70,24 @@ program-arty:
 .PHONY: lint-core-tracing
 lint-core-tracing:
 	fusesoc --cores-root . run --target=lint lowrisc:ibex:ibex_core_tracing
+
+
+# CS Registers testbench
+# Use the following targets:
+# - "build-csr-test"
+# - "run-csr-test"
+.PHONY: build-cs-registers
+build-csr-test:
+	fusesoc --cores-root=. run --target=sim --setup --build \
+	      --tool=verilator lowrisc:ibex:tb_cs_registers
+Vtb_cs_registers = \
+      build/lowrisc_ibex_tb_cs_registers_0/sim-verilator/Vtb_cs_registers
+$(Vtb_cs_registers):
+	@echo "$@ not found"
+	@echo "Run \"make build-csr-test\" to create the dependency"
+	@false
+
+.PHONY: run-cs-registers
+run-csr-test: | $(Vtb_cs_registers)
+	fusesoc --cores-root=. run --target=sim --run \
+	      --tool=verilator lowrisc:ibex:tb_cs_registers