build: reduce the number of places we list the MCU types

this is a step towards removing the recursive make, and making it
easier to add new MCUs

Makefile

@@ -22,17 +22,15 @@ ROOT := $(patsubst %/,%,$(dir $(lastword $(MAKEFILE_LIST))))
 # include the rules for OS independence
 include $(ROOT)/make/tools.mk
 
-# Include processor specific makefiles
-include f051makefile.mk
-include g071makefile.mk
-include f031makefile.mk
-include f421makefile.mk
-include e230makefile.mk
-include f415makefile.mk
-include gd32makefile.mk
-
-# Default MCU type to F051
-MCU_TYPE ?= F051
+# supported MCU types
+MCU_TYPES := E230 F031 F051 F415 F421 G071
+MCU_TYPE := NONE
+
+# Function to include makefile for each MCU type
+define INCLUDE_MCU_MAKEFILES
+$(foreach MCU_TYPE,$(MCU_TYPES),$(eval include $(call lc,$(MCU_TYPE))makefile.mk))
+endef
+$(call INCLUDE_MCU_MAKEFILES)
 
 # additional libs
 LIBS := -lnosys
@@ -44,9 +42,11 @@ VERSION_MINOR := $(shell $(FGREP) "define VERSION_MINOR" $(MAIN_INC_DIR)/version
 FIRMWARE_VERSION := $(VERSION_MAJOR).$(VERSION_MINOR)
 
 # Compiler options
-CFLAGS_COMMON := -DUSE_MAKE -fsingle-precision-constant -fomit-frame-pointer -ffast-math
-CFLAGS_COMMON += -I$(MAIN_INC_DIR) -g -O3 -Wall -ffunction-sections
-CFLAGS_COMMON += -D$(TARGET)
+
+CFLAGS_BASE := -DUSE_MAKE -fsingle-precision-constant -fomit-frame-pointer -ffast-math
+CFLAGS_BASE += -I$(MAIN_INC_DIR) -g -O3 -Wall -ffunction-sections
+
+CFLAGS_COMMON := $(CFLAGS_BASE) -D$(TARGET)
 
 # Linker options
 LDFLAGS_COMMON := -specs=nano.specs $(LIBS) -Wl,--gc-sections -Wl,--print-memory-usage
@@ -61,52 +61,37 @@ TARGET_BASENAME = $(BIN_DIR)/$(TARGET_FNAME)
 OBJ := obj
 BIN_DIR := $(ROOT)/$(OBJ)
 
-TOOLS_DIR ?= $(ROOT)/tools
-DL_DIR := $(ROOT)/downloads
-
-.PHONY : clean all binary f051 g071 f031 e230 f421 f415
-ALL_TARGETS := $(TARGETS_F051) $(TARGETS_G071) $(TARGETS_F031) $(TARGETS_E230) $(TARGETS_F421) $(TARGETS_F415)
+.PHONY : clean all binary $(foreach MCU,$(MCU_TYPES),$(call lc,$(MCU)))
+ALL_TARGETS := $(foreach MCU,$(MCU_TYPES),$(TARGETS_$(MCU)))
 all : $(ALL_TARGETS)
-f051 : $(TARGETS_F051)
-g071 : $(TARGETS_G071)
-f031 : $(TARGETS_F031)
-e230 : $(TARGETS_E230)
-f421 : $(TARGETS_F421)
-f415 : $(TARGETS_F415)
+
+# create targets for compiling one mcu type, eg "make f421"
+define CREATE_TARGET
+$(call lc,$(1)) : $$(TARGETS_$(1))
+endef
+$(foreach MCU,$(MCU_TYPES),$(eval $(call CREATE_TARGET,$(MCU))))
 
 clean :
 	@echo Removing $(OBJ) directory
 	@$(RM) -rf $(OBJ)
 
-# lowercase version of MCU_TYPE
-MCU_LOWER = $(call lc,$(MCU_TYPE))
 
 binary : $(TARGET_BASENAME).bin
 # we copy debug.elf to give us a constant debug target for vscode
 # this means the debug button will always debug the last target built
 	@$(CP) -f $(OBJ)$(DSEP)$(TARGET_FNAME).elf $(OBJ)$(DSEP)debug.elf > $(NUL)
 # also copy the openocd.cfg from the MCU directory to obj/openocd.cfg for auto config of Cortex-Debug
 # in vscode
-	@$(CP) -f Mcu$(DSEP)$(MCU_LOWER)$(DSEP)openocd.cfg $(OBJ)$(DSEP)openocd.cfg > $(NUL)
+	@$(CP) -f Mcu$(DSEP)$(call lc,$(MCU_TYPE))$(DSEP)openocd.cfg $(OBJ)$(DSEP)openocd.cfg > $(NUL)
 	@$(ECHO) done $(TARGET)
 
-$(TARGETS_F051) :
-	@$(MAKE) -s MCU_TYPE=F051 TARGET=$@ binary
-
-$(TARGETS_G071) :
-	@$(MAKE) -s MCU_TYPE=G071 TARGET=$@ binary
+# create targets compiling each MCU types targets
+define CREATE_MCU_TARGETS
+$$(TARGETS_$(1)) :
+	@$$(MAKE) -s MCU_TYPE=$(1) TARGET=$$@ binary
+endef
+$(foreach MCU,$(MCU_TYPES),$(eval $(call CREATE_MCU_TARGETS,$(MCU))))
 
-$(TARGETS_F031) :
-	@$(MAKE) -s MCU_TYPE=F031 TARGET=$@ binary
-
-$(TARGETS_E230) :
-	@$(MAKE) -s MCU_TYPE=E230 TARGET=$@ binary
-
-$(TARGETS_F421) :
-	@$(MAKE) -s MCU_TYPE=F421 TARGET=$@ binary	
-
-$(TARGETS_F415) :
-	@$(MAKE) -s MCU_TYPE=F415 TARGET=$@ binary		
 
 # Compile target
 $(TARGET_BASENAME).elf: CFLAGS := $(MCU_$(MCU_TYPE)) $(CFLAGS_$(MCU_TYPE)) $(CFLAGS_COMMON)
@@ -122,22 +107,13 @@ $(TARGET_BASENAME).bin: $(TARGET_BASENAME).elf
 	$(QUIET)$(OBJCOPY) -O binary $(<) $@
 	$(QUIET)$(OBJCOPY) $(<) -O ihex $(@:.bin=.hex)
 
-# mkdirs
-$(DL_DIR):
-	$(QUIET)$(MKDIR) -p $@
-
-$(TOOLS_DIR):
-	$(QUIET)$(MKDIR) -p $@
-
 # include the targets for installing tools
 include $(ROOT)/make/tools_install.mk
 
+define SHOW_MCU_TARGETS
+$(1) Targets $(TARGETS_$(1))\n
+endef
+
 targets:
-	$(QUIET)echo Targets for each MCU. To build a target use 'make TARGETNAME'
-	$(QUIET)echo F051 Targets:  $(TARGETS_F051)
-	$(QUIET)echo G071 Targets: $(TARGETS_G071)
-	$(QUIET)echo F031 Targets: $(TARGETS_F031)
-	$(QUIET)echo E230 Targets: $(TARGETS_E230)
-	$(QUIET)echo F421 Targets: $(TARGETS_F421)
-	$(QUIET)echo F415 Targets: $(TARGETS_F415)
-	$(QUIET)echo GD32 Targets: $(TARGETS_GD32)
+	$(QUIET)echo List of targets. To build a target use 'make TARGETNAME'
+	$(QUIET)echo $(ALL_TARGETS)