Speedup the key tool builds.

Makefile

@@ -163,8 +163,9 @@ $(PRIVATE_KEY):
 	$(Q)(test $(SIGN) = NONE) && (echo "// SIGN=NONE" >  src/keystore.c) || true
 
 keytools:
+	@echo "Building key tools"
 	@$(MAKE) -C tools/keytools -s clean
-	@$(MAKE) -C tools/keytools
+	@$(MAKE) -C tools/keytools -j
 
 test-app/image_v1_signed.bin: $(BOOT_IMG)
 	@echo "\t[SIGN] $(BOOT_IMG)"

tools/keytools/Makefile

@@ -8,10 +8,13 @@ ifeq ($(V),0)
 endif
 
 CC      = gcc
+LD      = gcc
 WOLFBOOTDIR = ../..
-WOLFDIR = $(WOLFBOOTDIR)/lib/wolfssl/
+WOLFDIR = $(WOLFBOOTDIR)/lib/wolfssl
 CFLAGS  = -Wall -Wextra -Werror
 CFLAGS  += -I. -DWOLFSSL_USER_SETTINGS -I$(WOLFDIR) -I$(WOLFBOOTDIR)/include -DWOLFBOOT_KEYTOOLS
+LDFLAGS =
+OBJDIR = ./
 
 # option variables
 DEBUG_FLAGS     = -g -DDEBUG -DDEBUG_SIGNTOOL -DDEBUG_WOLFSSL -DDEBUG_WOLFSSL_VERBOSE -fsanitize=address
@@ -35,33 +38,40 @@ else ifeq ($(RENESAS_KEY),2)
 endif
 
 # Sources
-SRC=$(WOLFDIR)wolfcrypt/src/asn.c \
-	$(WOLFDIR)wolfcrypt/src/aes.c \
-	$(WOLFDIR)wolfcrypt/src/ecc.c \
-	$(WOLFDIR)wolfcrypt/src/coding.c \
-	$(WOLFDIR)wolfcrypt/src/chacha.c \
-	$(WOLFDIR)wolfcrypt/src/ed25519.c \
-	$(WOLFDIR)wolfcrypt/src/ed448.c \
-	$(WOLFDIR)wolfcrypt/src/fe_operations.c \
-	$(WOLFDIR)wolfcrypt/src/ge_operations.c \
-	$(WOLFDIR)wolfcrypt/src/fe_448.c \
-	$(WOLFDIR)wolfcrypt/src/ge_448.c \
-	$(WOLFDIR)wolfcrypt/src/hash.c \
-	$(WOLFDIR)wolfcrypt/src/logging.c \
-	$(WOLFDIR)wolfcrypt/src/memory.c \
-	$(WOLFDIR)wolfcrypt/src/random.c \
-	$(WOLFDIR)wolfcrypt/src/rsa.c \
-	$(WOLFDIR)wolfcrypt/src/sp_int.c \
-	$(WOLFDIR)wolfcrypt/src/sp_c32.c \
-	$(WOLFDIR)wolfcrypt/src/sp_c64.c \
-	$(WOLFDIR)wolfcrypt/src/sha3.c \
-	$(WOLFDIR)wolfcrypt/src/sha256.c \
-	$(WOLFDIR)wolfcrypt/src/sha512.c \
-	$(WOLFDIR)wolfcrypt/src/tfm.c \
-	$(WOLFDIR)wolfcrypt/src/wc_port.c \
-	$(WOLFDIR)wolfcrypt/src/wolfmath.c
+OBJS_REAL=\
+	$(WOLFDIR)/wolfcrypt/src/asn.o \
+	$(WOLFDIR)/wolfcrypt/src/aes.o \
+	$(WOLFDIR)/wolfcrypt/src/ecc.o \
+	$(WOLFDIR)/wolfcrypt/src/coding.o \
+	$(WOLFDIR)/wolfcrypt/src/chacha.o \
+	$(WOLFDIR)/wolfcrypt/src/ed25519.o \
+	$(WOLFDIR)/wolfcrypt/src/ed448.o \
+	$(WOLFDIR)/wolfcrypt/src/fe_operations.o \
+	$(WOLFDIR)/wolfcrypt/src/ge_operations.o \
+	$(WOLFDIR)/wolfcrypt/src/fe_448.o \
+	$(WOLFDIR)/wolfcrypt/src/ge_448.o \
+	$(WOLFDIR)/wolfcrypt/src/hash.o \
+	$(WOLFDIR)/wolfcrypt/src/logging.o \
+	$(WOLFDIR)/wolfcrypt/src/memory.o \
+	$(WOLFDIR)/wolfcrypt/src/random.o \
+	$(WOLFDIR)/wolfcrypt/src/rsa.o \
+	$(WOLFDIR)/wolfcrypt/src/sp_int.o \
+	$(WOLFDIR)/wolfcrypt/src/sp_c32.o \
+	$(WOLFDIR)/wolfcrypt/src/sp_c64.o \
+	$(WOLFDIR)/wolfcrypt/src/sha3.o \
+	$(WOLFDIR)/wolfcrypt/src/sha256.o \
+	$(WOLFDIR)/wolfcrypt/src/sha512.o \
+	$(WOLFDIR)/wolfcrypt/src/tfm.o \
+	$(WOLFDIR)/wolfcrypt/src/wc_port.o \
+	$(WOLFDIR)/wolfcrypt/src/wolfmath.o
 
-SRC+=$(WOLFBOOTDIR)/src/delta.c
+OBJS_REAL+=\
+	$(WOLFBOOTDIR)/src/delta.o
+
+OBJS_VIRT=$(addprefix $(OBJDIR), $(notdir $(OBJS_REAL)))
+vpath %.c $(WOLFDIR)/wolfcrypt/src/
+vpath %.c $(WOLFBOOTDIR)/src/
+vpath %.c ./
 
 .PHONY: clean all
 
@@ -84,14 +94,22 @@ $(WOLFBOOTDIR)/include/target.h: $(WOLFBOOTDIR)/include/target.h.in
 	sed -e "s/@WOLFBOOT_LOAD_DTS_ADDRESS@/$(WOLFBOOT_LOAD_DTS_ADDRESS)/g" \
 		> $@
 
-# build template
-sign:
-	@echo "Building signing tool"
-	$(Q)$(CC) -o $@ $@.c $(SRC) $< $(CFLAGS)
+# build objects
+$(OBJDIR)/%.o: %.c
+	$(Q)$(CC) $(CFLAGS) -c -o $@ $<
+$(OBJDIR)/%.o: $(WOLFBOOTDIR)/src/%.c
+	$(Q)$(CC) $(CFLAGS) -c -o $@ $<
+$(OBJDIR)/%.o: $(WOLFDIR)/wolfcrypt/src/%.c
+	$(Q)$(CC) $(CFLAGS) -c -o $@ $<
 
-keygen:
+# build templates
+sign: $(OBJS_VIRT) sign.o
+	@echo "Building signing tool"
+	$(Q)$(LD) -o $@ $@.o $(OBJS_VIRT) $(LDFLAGS)
+
+keygen: $(OBJS_VIRT) keygen.o
 	@echo "Building keygen tool"
-	$(Q)$(CC) -o $@ $@.c $(SRC) $< $(CFLAGS)
+	$(Q)$(LD) -o $@ $@.o $(OBJS_VIRT) $(LDFLAGS)
 
 clean:
-	rm -f sign keygen
+	rm -f sign keygen *.o