[cheshire] Fix relative path in makefile

cheshire/Makefile

@@ -2,13 +2,14 @@
 # Solderpad Hardware License, Version 0.51, see LICENSE for details.
 # SPDX-License-Identifier: SHL-0.51
 #
-# Author: Moritz Imfeld <[email protected]>
+# Author: Moritz Imfeld  <[email protected]>
+# Author: Matteo Perotti <[email protected]>
 #
 
 # Chshire root reposiotry
 MAKEFILE_DIR            := $(dir $(abspath $(lastword $(MAKEFILE_LIST))))
 ARA_ROOT                := $(MAKEFILE_DIR)/..
-BACKREF_CHS_ROOT        ?= ../../../../..
+BACKREF_CHS_ROOT        ?= $(realpath ../../../../..)
 BACKREF_CHS_XIL_SCRIPTS := $(BACKREF_CHS_ROOT)/target/xilinx/scripts
 
 
@@ -19,15 +20,14 @@ include $(ARA_ROOT)/config/$(ARA_CONFIGURATION).mk
 BOARD                   := vcu128
 CUSTOM_BENDER_TARGETS   := -t fpga -t cv64a6_imafdcv_sv39 -t cva6 -t $(BOARD) --define ARA --define NR_LANES=$(nr_lanes) --define VLEN=$(vlen)
 
-.PHONY: ara-chs-xilinx-$(BOARD) clean
+.PHONY: ara-chs-xilinx-$(BOARD) update_xilinx_src clean
 
-ara-chs-xilinx-$(BOARD): $(MAKEFILE_DIR)/add_sources.vcu128.tcl
+ara-chs-xilinx-$(BOARD): update_xilinx_src
 	make -C $(BACKREF_CHS_ROOT) chs-xilinx-$(BOARD)
 
-$(MAKEFILE_DIR)/add_sources.vcu128.tcl:
+update_xilinx_src:
 	cd $(BACKREF_CHS_ROOT) && \
-	bender script vivado $(CUSTOM_BENDER_TARGETS) > $@ && \
-	cp $(MAKEFILE_DIR)/add_sources.vcu128.tcl $(BACKREF_CHS_XIL_SCRIPTS)/add_sources.vcu128.tcl
+	bender script vivado $(CUSTOM_BENDER_TARGETS) > $(BACKREF_CHS_XIL_SCRIPTS)/add_sources.vcu128.tcl
 
 clean:
 	rm $(BACKREF_CHS_XIL_SCRIPTS)/add_sources.vcu128.tcl