Make it easier to flash different devices and use ST-Link programmer

- Added parameters to specify a programmer (interface) for openocd to use

- Added device name to firmware blobs so the flash command won't upload
  firmware to a device unless it was compiled for that device.

- Added small scripts to leverage the DEVICE parameter as much as possible
  in the build process. This includes automatically determining openocd
  target config from DEVICE, and getting the ROM/RAM size information
  already present in libopencm3 (but poorly exposed)

- Moved Makefile to project root for consistency with other projects

- Removed opencm3 build as a makefile dependency. `genlink-config.mk` in
  opencm3 isn't written in a way that can be used as a build dependency,
  since it refuses to set a library name if the name it wants to use
  doesn't exist on disk already. This means the make has to be run twice
  to actually succeed.

- Added credit to size script. This was mentioned in an Embedded Artistry
  newsletter a while ago and I hadn't intended to widely distribute this
  copy of it.

Resolves #5

Makefile

@@ -0,0 +1,83 @@
+# Device to build for
+# See libopencm3/ld/devices.data for valid device name patterns
+DEVICE ?= stm32f103c8
+
+# Programmer to use (name of interface config in OpenOCD)
+# For ST-Link v1 or v2 programmers, use "stlink"
+# See the interfaces/*.cfg files installed by openocd for options
+PROGRAMMER ?= jlink
+
+# Serial number for USB interface (must be 12 or more characters in hex)
+SERIALNUM ?= D000000000E7
+CDEFS += -DUSB_SERIALNUM="\"$(SERIALNUM)\""
+
+# Base OpenCM3 build
+PROJECT = boot-swtich
+
+CFILES = \
+	src/clock.c \
+	src/fat.c \
+	src/main.c \
+	src/usb.c \
+
+CSTD = -std=c11
+OPT = -Os
+
+# Flag specific devices that needs special pin mapping
+ifeq ($(DEVICE), stm32f070f6)
+	CDEFS += -DSTM32F070F6
+endif
+
+
+# Pick OpenOCD target config based on DEVICE parameter if not set externally
+OOCD_TARGET ?= $(shell python ./scripts/openocd_target.py $(DEVICE))
+
+# Pick appropriate transport for programmer
+ifeq ($(PROGRAMMER), stlink)
+	TRANSPORT ?= hla_swd
+else
+	TRANSPORT ?= swd
+endif
+
+OOCD_FLAGS = -f interface/$(PROGRAMMER).cfg \
+             -c "transport select $(TRANSPORT)" \
+             -f target/$(OOCD_TARGET).cfg \
+             -f openocd.cfg
+
+
+# Generate the actual build targets based on this what's configured above
+OPENCM3_DIR=libopencm3
+include $(OPENCM3_DIR)/mk/genlink-config.mk
+include rules.mk
+include $(OPENCM3_DIR)/mk/genlink-rules.mk
+
+# Extract parameters for size script from generated device flags
+genlink_defs = $(shell $(OPENCM3_DIR)/scripts/genlink.py $(DEVICES_DATA) $(DEVICE) DEFS)
+FLASH_SIZE_BYTES = $(shell python ./scripts/parse_defs.py _ROM $(genlink_defs))
+SRAM_SIZE_BYTES = $(shell python ./scripts/parse_defs.py _RAM $(genlink_defs))
+
+test:
+	@echo $(genlink_cppflags)
+	@echo $(FLASH_SIZE_BYTES) $(SRAM_SIZE_BYTES)
+
+reset:
+	$(OOCD) -f $(OOCD_FILE) -c 'reset ()'
+
+flash: all
+	BINARY=$(OUTPUT_ELF) $(OOCD) $(OOCD_FLAGS) -c 'program_and_run ()'
+
+flash_and_debug: all
+	BINARY=$(OUTPUT_ELF) $(OOCD) $(OOCD_FLAGS) -c 'program_and_attach ()'
+
+debug_server:
+	# This doesn't like being backgrounded from make for some reason
+	# Run this as a background task, then run debug_gdb
+	$(OOCD) $(OOCD_FLAGS) -c 'attach ()'
+
+debug_gdb:
+	$(GDB) $(OUTPUT_ELF) -ex 'target remote :3333' \
+
+disasm: $(OUTPUT_ELF)
+	$(OBJDUMP) -d $(OUTPUT_ELF)
+
+.PHONY: flash reset debug_gdb debug_server disasm

README.md

@@ -13,22 +13,30 @@ git submodule init
 git submodule update
 
 # Build libopencm3 (only needed once)
-cd libopencm3
-make -j8
+make -C libopencm3 -j8
 
 # Build the firmware
-cd src
 make
 
-# Flash (assumes a J-Link programmer connected to SWD on the device)
+# Flash with a J-Link programmer connected by SWD
 make flash
+
+# Flash with an ST-Link programmer connected by SWD
+make flash PROGRAMMER=stlink
 ```
 
-This project supports building for multiple different parts. Use `make DEVICE=partnumber` to build for a specific part. These parts have been tested:
+This project supports building and flashing multiple different parts. These parts have been tested:
 
 - `stm32f103c8` (default): found on the "blue pill" and "maple" STM32 dev boards
 - `stm32f070f6`
 
+To build for your specific part, pass the `DEVICE` parameter to `make` on the command line (or export `DEVICE` as an environment variable):
+
+```sh
+make DEVICE=stm32f070f6
+make flash DEVICE=stm32f070f6
+```
+
 Valid patterns for the `DEVICE` parameter can be found in `libopencm3/ld/devices.data`.
 
 

openocd-jlink.cfg → openocd.cfg

@@ -1,9 +1,5 @@
-# Configure JLink in SWD mode
-source [find interface/jlink.cfg]
-transport select swd
-
-# STM32F070 target
-source [find target/stm32f0x.cfg]
+# Interface and target device config are specified on the command line
+# See src/Makefile OOCD_FLAGS
 
 # Init and flash target
 proc program () {

rules.mk

@@ -67,6 +67,9 @@ ifndef GDB
 	GDB = $(PREFIX)gdb
 endif
 
+# Filename to build to
+OUTPUT_ELF = $(PROJECT).$(DEVICE).elf
+OUTPUT_BIN = $(PROJECT).$(DEVICE).bin
 
 OPENCM3_INC = $(OPENCM3_DIR)/include
 
@@ -75,7 +78,7 @@ INCLUDES += $(patsubst %,-I%, . $(OPENCM3_INC) )
 
 OBJS = $(CFILES:%.c=$(BUILD_DIR)/%.o)
 OBJS += $(AFILES:%.S=$(BUILD_DIR)/%.o)
-GENERATED_BINS = $(PROJECT).elf $(PROJECT).bin $(PROJECT).map $(PROJECT).list $(PROJECT).lss
+GENERATED_BINS = $(PROJECT)*.elf $(PROJECT)*.bin $(PROJECT)*.map $(PROJECT)*.list $(PROJECT)*.lss
 
 TGT_CPPFLAGS += -MD
 TGT_CPPFLAGS += -Wall -Wundef $(INCLUDES)
@@ -127,7 +130,7 @@ LDLIBS += -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group
 %: s.%
 %: SCCS/s.%
 
-all: $(PROJECT).elf $(PROJECT).bin
+all: $(OUTPUT_ELF) $(OUTPUT_BIN)
 
 # error if not using linker script generator
 ifeq (,$(DEVICE))
@@ -140,10 +143,6 @@ else
 GENERATED_BINS += $(LDSCRIPT)
 endif
 
-# Ensure the platform we want from libopencm3 is compiled
-opencm3:
-	$(Q)$(MAKE) -C $(OPENCM3_DIR) TARGETS=stm32/f0
-
 # Need a special rule to have a bin dir
 $(BUILD_DIR)/%.o: %.c
 	@printf "  CC\t$<\n"
@@ -160,7 +159,7 @@ $(BUILD_DIR)/%.o: %.S
 	@mkdir -p $(dir $@)
 	$(Q)$(CC) $(TGT_ASFLAGS) $(ASFLAGS) $(TGT_CPPFLAGS) $(CPPFLAGS) -o $@ -c $<
 
-$(PROJECT).elf: opencm3 $(OBJS) $(LDSCRIPT) $(LIBDEPS)
+$(OUTPUT_ELF): opencm3 $(OBJS) $(LDSCRIPT) $(LIBDEPS)
 	@printf "  LD\t$@\n"
 	$(Q)$(LD) $(TGT_LDFLAGS) $(LDFLAGS) $(OBJS) $(LDLIBS) -o $@
 
@@ -169,7 +168,7 @@ $(PROJECT).elf: opencm3 $(OBJS) $(LDSCRIPT) $(LIBDEPS)
 	$(Q)$(OBJCOPY) -O binary  $< $@
 
 	@printf "\nFirmware size ($<):\n"
-	@../scripts/size.sh $< $(FLASH_SIZE_BYTES) $(SRAM_SIZE_BYTES)
+	@./scripts/size.sh $< $(FLASH_SIZE_BYTES) $(SRAM_SIZE_BYTES)
 
 %.lss: %.elf
 	$(OBJDUMP) -h -S $< > $@
@@ -180,11 +179,6 @@ $(PROJECT).elf: opencm3 $(OBJS) $(LDSCRIPT) $(LIBDEPS)
 clean:
 	rm -rf $(BUILD_BASE) $(GENERATED_BINS)
 
-	$(Q)if [ -d $* ]; then \
-		printf "  CLEAN   $*\n"; \
-		$(MAKE) -C $* clean OPENCM3_DIR=$(OPENCM3_DIR) || exit $?; \
-	fi;
-
 .PHONY: all clean opencm3
 -include $(OBJS:.o=.d)
 

scripts/openocd_target.py

@@ -0,0 +1,23 @@
+#
+# Print an OpenOCD target name for a given libopencm3 device name
+# This could be done with sed from Make, but I expect this to grow
+#
+
+from __future__ import print_function
+
+import sys
+import re
+
+if len(sys.argv) < 2:
+    print("Usage: %s <DEVICE>")
+    sys.exit(1)
+
+device = sys.argv[1]
+
+if device.startswith('stm32'):
+    match = re.match(r'(stm32f[0-9]).*', device)
+    print(match.group(1) + "x")
+
+else:
+    sys.stderr.write("Unsure how to determine OpenOCD target config for '%s'" % device)
+    sys.exit(2)

scripts/parse_defs.py

@@ -0,0 +1,35 @@
+#
+# Extract a particular definition (-D) value from passed compiler args
+#
+# This is a bit messy as the genlink.py script in libopencm3 isn't written in
+# a way that allows reuse of its parsing code in other Python scripts. This
+# script primarily exists to parse RAM and ROM size data from genlink.py.
+#
+
+from __future__ import print_function
+
+import re
+import sys
+
+if len(sys.argv) < 2:
+    print("Usage: %s <NAME> [-Dvar=value, ...]")
+    sys.exit(1)
+
+search = sys.argv[1]
+pattern = "-D%s=" % search
+value = None
+
+for arg in sys.argv[2:]:
+    if arg.startswith(pattern):
+        value = arg[len(pattern):]
+        break
+else:
+    print("Couldn't find variable named '%s' in args: %s" % (search, sys.argv[2:]))
+    sys.exit(2)
+
+# Convert kilobytes to bytes
+match = re.match(r'([0-9]+)K', value)
+if match:
+    value = int(match.group(1)) * 1024
+
+print(value)

scripts/size.sh

@@ -1,5 +1,8 @@
 #!/bin/bash
 
+# Print the RAM and ROM use percent of compiled firmware
+# Based on https://interrupt.memfault.com/blog/best-firmware-size-tools
+
 if [  $# -le 2 ]
 then
     echo "This script requires 3 arguments."