stm32: initial support

.gitignore

@@ -3,3 +3,5 @@ src/device/avr/*.go
 src/device/avr/*.ld
 src/device/nrf/*.go
 src/device/nrf/*.s
+src/device/stm32/*.go
+src/device/stm32/*.s

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "lib/avr"]
 	path = lib/avr
 	url = https://github.com/avr-rust/avr-mcu.git
+[submodule "lib/cmsis-svd"]
+	path = lib/cmsis-svd
+	url = https://github.com/posborne/cmsis-svd

Makefile

@@ -15,6 +15,12 @@ else ifeq ($(TARGET),pca10040)
 OBJCOPY = arm-none-eabi-objcopy
 TGOFLAGS += -target $(TARGET)
 
+else ifeq ($(TARGET),bluepill)
+# "blue pill" development board
+# See: https://wiki.stm32duino.com/index.php?title=Blue_Pill
+OBJCOPY = arm-none-eabi-objcopy
+TGOFLAGS += -target $(TARGET)
+
 else ifeq ($(TARGET),arduino)
 OBJCOPY = avr-objcopy
 TGOFLAGS += -target $(TARGET)
@@ -39,6 +45,9 @@ flash-%: build/%.hex
 else ifeq ($(TARGET),arduino)
 flash-%: build/%.hex
 	avrdude -c arduino -p atmega328p -P /dev/ttyACM0 -U flash:w:$<
+else ifeq ($(TARGET),bluepill)
+flash-%: build/%.hex
+	openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg -c 'program $< reset exit'
 endif
 
 clean:
@@ -57,6 +66,10 @@ gen-device-avr:
 	./tools/gen-device-avr.py lib/avr/packs/atmega src/device/avr/
 	go fmt ./src/device/avr
 
+gen-device-stm32:
+	./tools/gen-device-svd.py lib/cmsis-svd/data/STMicro/ src/device/stm32/ --source=https://github.com/posborne/cmsis-svd/tree/master/data/STMicro
+	go fmt ./src/device/stm32
+
 
 # Build the Go compiler.
 build/tgo: *.go

lib/cmsis-svd

@@ -0,0 +1 @@
+Subproject commit 2ab163c2aea83eb9b39c163856450089255ce4f2

src/machine/machine_dummy.go

@@ -1,4 +1,4 @@
-// +build !avr,!nrf
+// +build !avr,!nrf,!stm32
 
 package machine
 

src/machine/machine_stm32.go

@@ -0,0 +1,81 @@
+// +build stm32
+
+package machine
+
+// Peripheral abstraction layer for the stm32.
+
+import (
+	"device/stm32"
+)
+
+type GPIOMode uint8
+
+const (
+	GPIO_INPUT  = 0 // Input mode
+	GPIO_OUTPUT = 2 // Output mode, max speed 2MHz
+)
+
+const (
+	portA = iota * 16
+	portB
+	portC
+	portD
+	portE
+	portF
+	portG
+)
+
+const (
+	LED = portC + 13
+)
+
+func (p GPIO) getPort() *stm32.GPIO_Type {
+	switch p.Pin / 16 {
+	case 0:
+		return stm32.GPIOA
+	case 1:
+		return stm32.GPIOB
+	case 2:
+		return stm32.GPIOC
+	case 3:
+		return stm32.GPIOD
+	case 4:
+		return stm32.GPIOE
+	case 5:
+		return stm32.GPIOF
+	case 6:
+		return stm32.GPIOG
+	default:
+		panic("machine: unknown port")
+	}
+}
+
+// Configure this pin with the given configuration.
+func (p GPIO) Configure(config GPIOConfig) {
+	// Enable clock.
+	// Do this always, as it isn't known whether the clock has already been
+	// enabled.
+	stm32.RCC.APB2ENR |= stm32.RCC_APB2ENR_IOPCEN_Msk;
+
+	// Configure the GPIO pin.
+	port := p.getPort()
+	pin := p.Pin % 16
+	pos := p.Pin % 8 * 4
+	if pin < 8 {
+		port.CRL = stm32.RegValue((uint32(port.CRL) &^ (0xf << pos)) | (uint32(config.Mode) << pos))
+	} else {
+		port.CRH = stm32.RegValue((uint32(port.CRH) &^ (0xf << pos)) | (uint32(config.Mode) << pos))
+	}
+}
+
+// Set the pin to high or low.
+// Warning: only use this on an output pin!
+func (p GPIO) Set(high bool) {
+	port := p.getPort()
+	pin := p.Pin % 16
+	if high {
+		port.BSRR = 1 << pin
+	} else {
+		port.BSRR = 1 << (pin + 16)
+	}
+}

src/runtime/runtime_stm32.go

@@ -0,0 +1,34 @@
+// +build stm32
+
+package runtime
+
+import (
+	"device/arm"
+)
+
+type timeUnit int64
+
+const tickMicros = 1 // TODO
+
+//go:export Reset_Handler
+func handleReset() {
+	main()
+}
+
+func init() {
+}
+
+func putchar(c byte) {
+	// TODO
+}
+
+func sleepTicks(d timeUnit) {
+	// TODO: use a real timer here
+	for i := 0; i < int(d/535); i++ {
+		arm.Asm("")
+	}
+}
+
+func ticks() timeUnit {
+	return 0 // TODO
+}

targets/bluepill.json

@@ -0,0 +1,8 @@
+{
+	"llvm-target": "armv7m-none-eabi",
+	"build-tags": ["stm32", "stm32f103xx", "arm", "js", "wasm"],
+	"linker": "arm-none-eabi-gcc",
+	"pre-link-args": ["-nostdlib", "-nostartfiles", "-mcpu=cortex-m3", "-mthumb", "-T", "targets/stm32.ld", "-Wl,--gc-sections", "-fno-exceptions", "-fno-unwind-tables", "-ffunction-sections", "-fdata-sections", "-Os", "src/device/stm32/stm32f103xx.s"],
+	"objcopy": "arm-none-eabi-objcopy",
+	"flash": "openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg -c 'program {hex} reset exit'"
+}

targets/stm32.ld

@@ -0,0 +1,10 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x08000000, LENGTH = 64K
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+_stack_size = 2K;
+
+INCLUDE "targets/arm.ld"