samd51,rp2040,nrf528xx,stm32: implement watchdog

src/machine/watchdog.go

@@ -0,0 +1,34 @@
+//go:build nrf52840 || nrf52833 || rp2040 || atsamd51 || atsame5x || stm32
+
+package machine
+
+// WatchdogConfig holds configuration for the watchdog timer.
+type WatchdogConfig struct {
+	// The timeout (in milliseconds) before the watchdog fires.
+	//
+	// If the requested timeout exceeds `MaxTimeout` it will be rounded
+	// down.
+	TimeoutMillis uint32
+}
+
+// watchdog must be implemented by any platform supporting watchdog functionality
+type watchdog interface {
+	// Configure the watchdog.
+	//
+	// This method should not be called after the watchdog is started and on
+	// some platforms attempting to reconfigure after starting the watchdog
+	// is explicitly forbidden / will not work.
+	Configure(config WatchdogConfig) error
+
+	// Starts the watchdog.
+	Start() error
+
+	// Update the watchdog, indicating that the app is healthy.
+	Update()
+}
+
+// Ensure required public symbols var exists and meets interface spec
+var _ = watchdog(Watchdog)
+
+// Ensure required public constants exist
+const _ = WatchdogMaxTimeout