Added Black Magic Probe support to the stm32 platform.

Just add BMP_PORT=/dev/ttyACM0 to the ap.upload make call. The script
will try to flash the device using GDB and the BMP.

conf/Makefile.stm32

@@ -52,6 +52,7 @@ CP   = $(GCC_BIN_PREFIX)-objcopy
 DMP  = $(GCC_BIN_PREFIX)-objdump
 NM   = $(GCC_BIN_PREFIX)-nm
 SIZE = $(GCC_BIN_PREFIX)-size
+GDB  = $(GCC_BIN_PREFIX)-gdb
 RM   = rm
 
 # If we can't find the toolchain then try picking up the compilers from the path
@@ -62,8 +63,10 @@ CP   = $(shell which arm-none-eabi-objcopy)
 DMP  = $(shell which arm-none-eabi-objdump)
 NM   = $(shell which arm-none-eabi-nm)
 SIZE = $(shell which arm-none-eabi-size)
+GDB  = $(shell which arm-none-eabi-gdb)
 RM   = rm
-GCC_LIB_DIR=$(shell dirname `which arm-none-eabi-gcc`)/../arm-none-eabi/lib
+TOOLCHAIN_DIR=$(shell dirname `which arm-none-eabi-gcc`)
+GCC_LIB_DIR=$(TOOLCHAIN_DIR)/../arm-none-eabi/lib
 endif
 
 # Detect if we are using the new libopencm3 or the old libopenstm32
@@ -250,7 +253,8 @@ ifeq ($(FLASH_MODE),SERIAL)
 upload: $(OBJDIR)/$(TARGET).bin
 	$(LOADER) -p /dev/ttyUSB0  -b 115200 -e -w -v $^
 else ifeq ($(FLASH_MODE),JTAG)
-upload:  $(OBJDIR)/$(TARGET).elf
+ifeq ($(BMP_PORT),)
+upload: $(OBJDIR)/$(TARGET).elf
 	@echo "Using OOCD = $(OOCD)"
 	@echo "  OOCD\t$<"
 	$(Q)$(OOCD) -f interface/$(OOCD_INTERFACE).cfg \
@@ -263,6 +267,16 @@ upload:  $(OBJDIR)/$(TARGET).elf
 		-c reset \
 		-c shutdown
 else
+upload: $(OBJDIR)/$(TARGET).elf
+	@echo "Using Black Magic Probe"
+	@echo "Using GDB = $(GDB)"
+	@echo "  BMP\t$<"
+	$(Q)$(GDB) --batch \
+		   -ex 'target extended-remote $(BMP_PORT)' \
+		   -x $(TOOLCHAIN_DIR)/arm-none-eabi/share/libopencm3/scripts/black_magic_probe_flash.scr \
+		   $<
+endif
+else
 upload:
 	@echo unknown flash_mode $(FLASH_MODE)
 endif