[syn] Use sv2v for prim_generic_buf

Convert `prim_generic_buf` to Verilog as well.
Also, replace 'prim_buf' with 'prim_generic_buf' whenever we see a
`prim_buf` in a generated Verilog file.

Fixes #1557

Signed-off-by: Canberk Topal <ctopal@lowrisc.org>

syn/syn_yosys.sh

@@ -32,10 +32,26 @@ source syn_setup.sh
 # use sv2v to convert all SystemVerilog files to Verilog
 #-------------------------------------------------------------------------
 
+LR_DEP_SOURCES=(
+    "../vendor/lowrisc_ip/ip/prim_generic/rtl/prim_generic_buf.sv"
+)
+
 mkdir -p "$LR_SYNTH_OUT_DIR/generated"
 mkdir -p "$LR_SYNTH_OUT_DIR/log"
 mkdir -p "$LR_SYNTH_OUT_DIR/reports/timing"
 
+# Convert dependency sources
+for file in ${LR_DEP_SOURCES[@]}; do
+    module=`basename -s .sv $file`
+
+    sv2v \
+        --define=SYNTHESIS --define=YOSYS \
+        -I../vendor/lowrisc_ip/ip/prim/rtl \
+        $file \
+        > $LR_SYNTH_OUT_DIR/generated/${module}.v
+done
+
+# Convert core sources
 for file in ../rtl/*.sv; do
   module=`basename -s .sv $file`
 
@@ -45,7 +61,7 @@ for file in ../rtl/*.sv; do
   fi
 
   sv2v \
-    --define=SYNTHESIS \
+    --define=SYNTHESIS --define=YOSYS \
     ../rtl/*_pkg.sv \
     ../vendor/lowrisc_ip/ip/prim/rtl/prim_ram_1p_pkg.sv \
     ../vendor/lowrisc_ip/ip/prim/rtl/prim_secded_pkg.sv \
@@ -53,6 +69,10 @@ for file in ../rtl/*.sv; do
     -I../vendor/lowrisc_ip/dv/sv/dv_utils \
     $file \
     > $LR_SYNTH_OUT_DIR/generated/${module}.v
+
+# Make sure auto-generated primitives are resolved to generic primitives
+# where available.
+  sed -i 's/prim_buf/prim_generic_buf/g'  $LR_SYNTH_OUT_DIR/generated/${module}.v
 done
 
 # remove tracer (not needed for synthesis)