amdfwtool: Clean up the Makefile of amdfwtool

Add Makefile.inc to compliant with other tools.
Makefile is kept for building amdfwtool by typing make
in the folder.

Change-Id: I3688d93de4459f5f838955892086b4b9bf30a9b8
Signed-off-by: Zheng Bao <fishbaozi@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45286
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

Makefile.inc

@@ -81,7 +81,7 @@ subdirs-y += $(wildcard src/soc/*/*) $(wildcard src/northbridge/*/*)
 subdirs-y += src/superio
 subdirs-y += $(wildcard src/drivers/*) $(wildcard src/drivers/*/*)
 subdirs-y += src/cpu src/vendorcode
-subdirs-y += util/cbfstool util/sconfig util/nvramtool util/pgtblgen
+subdirs-y += util/cbfstool util/sconfig util/nvramtool util/pgtblgen util/amdfwtool
 subdirs-y += util/futility util/marvell util/bincfg util/supermicro
 subdirs-y += $(wildcard src/arch/*)
 subdirs-y += src/mainboard/$(MAINBOARDDIR)
@@ -576,9 +576,6 @@ $(IFDTOOL):
 	cp -a $(top)/util/ifdtool/ifdtool $@
 
 AMDFWTOOL:=$(objutil)/amdfwtool/amdfwtool
-$(AMDFWTOOL): $(top)/util/amdfwtool/amdfwtool.c
-	@printf "    HOSTCC     $(subst $(obj)/,,$(@))\n"
-	$(HOSTCC) $(HOSTCFLAGS) -DCONFIG_ROM_SIZE=$(CONFIG_ROM_SIZE) -o $@ $<
 
 APCB_EDIT_TOOL:=$(top)/util/apcb/apcb_edit.py
 
@@ -1108,7 +1105,6 @@ RAMSTAGE=
 endif
 
 $(obj)/coreboot.rom: $(obj)/coreboot.pre $(RAMSTAGE) $(CBFSTOOL) $$(INTERMEDIATE)
-
 	@printf "    CBFS       $(subst $(obj)/,,$(@))\n"
 # The full ROM may be larger than the CBFS part, so create an empty
 # file (filled with \377 = 0xff) and copy the CBFS image over it.

util/amdfwtool/Makefile

@@ -1,16 +1,18 @@
-#*****************************************************************************
-#
-# All rights reserved.
-#
 # SPDX-License-Identifier: BSD-3-Clause
 
-#*****************************************************************************
 HOSTCC ?= cc
 
-amdfwtool_exe : amdfwtool.c
-	$(HOSTCC) amdfwtool.c -o amdfwtool
+SRC = amdfwtool.c
+OBJ = $(SRC:%.c=%.o)
+TARGET = amdfwtool
+CFLAGS=-O2 -Wall -Wextra -Wshadow
 
-amdfwtool : amdfwtool_exe
+
+$(TARGET): $(OBJ)
+	$(CC) $(OBJ) $(LDFLAGS) -o $@
+
+%.o: %.c $(HEADER)
+	$(CC) $(CFLAGS) -c -o $@ $<
 
 clean:
-	@rm -f amdfwtool.o amdfwtool amdfwtool.exe
+	@rm -f $(TARGET) $(OBJ)

util/amdfwtool/Makefile.inc

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+amdfwtoolobj = amdfwtool.o
+
+AMDFWTOOLCFLAGS=-O2 -Wall -Wextra -Wshadow
+
+$(objutil)/amdfwtool/%.o: $(top)/util/amdfwtool/%.c # $(HEADER)
+	$(HOSTCC) $(AMDFWTOOLCFLAGS) $(HOSTCFLAGS) -DCONFIG_ROM_SIZE=$(CONFIG_ROM_SIZE) -c -o $@ $<
+
+$(objutil)/amdfwtool/amdfwtool: $(addprefix $(objutil)/amdfwtool/,$(amdfwtoolobj))
+	printf "   AMDFWTOOL\n"
+	$(HOSTCC) $(addprefix $(objutil)/amdfwtool/,$(amdfwtoolobj)) -o $@