nina: BLE implementation on nina-fw

Makefile

@@ -32,6 +32,10 @@ smoketest-tinygo:
 	@md5sum test.hex
 	$(TINYGO) build -o test.hex -size=short -target=microbit-v2-s113v7    ./examples/nusserver
 	@md5sum test.hex
+	$(TINYGO) build -o test.uf2 -size=short -target=nano-rp2040 		  ./examples/scanner
+	@md5sum test.hex
+	$(TINYGO) build -o test.uf2 -size=short -target=nano-rp2040 		  ./examples/discover
+	@md5sum test.hex
 
 smoketest-linux:
 	# Test on Linux.

README.md

@@ -92,17 +92,17 @@ func must(action string, err error) {
 
 ## Current support
 
-|                                  | Linux              | macOS              | Windows            | Nordic Semi        |
-| -------------------------------- | ------------------ | ------------------ | ------------------ | ------------------ |
-| API used                         | BlueZ              | CoreBluetooth      | WinRT              | SoftDevice         |
-| Scanning                         | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
-| Connect to peripheral            | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
-| Write peripheral characteristics | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
-| Receive notifications            | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
-| Advertisement                    | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: |
-| Local services                   | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: |
-| Local characteristics            | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: |
-| Send notifications               | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: |
+|                                  | Linux              | macOS              | Windows            | Nordic Semi        | ESP32 (NINA-FW)        |
+| -------------------------------- | ------------------ | ------------------ | ------------------ | ------------------ | ------------------ |
+| API used                         | BlueZ              | CoreBluetooth      | WinRT              | SoftDevice         | HCI         	|
+| Scanning                         | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
+| Connect to peripheral            | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
+| Write peripheral characteristics | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
+| Receive notifications            | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
+| Advertisement                    | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: | :x:                |
+| Local services                   | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: | :x:                |
+| Local characteristics            | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: | :x:                |
+| Send notifications               | :heavy_check_mark: | :x:                | :x:                | :heavy_check_mark: | :x:                |
 
 ## Linux
 
@@ -264,6 +264,16 @@ After that, don't reset the board but instead flash a new program to it. For exa
 
 Flashing will normally reset the board.
 
+## ESP32 (NINA)
+
+Go Bluetooth has bare metal support for boards that include a separate ESP32 Bluetooth Low Energy radio co-processor. The ESP32 must be running the Arduino or Adafruit `nina_fw` firmware.
+
+See https://github.com/arduino/nina-fw for more information.
+
+The only currently supported board is the Arduino Nano RP2040 Connect.
+
+More info soon...
+
 ## API stability
 
 **The API is not stable!** Because many features are not yet implemented and some platforms (e.g. Windows and macOS) are not yet fully supported, it's hard to say what a good API will be. Therefore, if you want stability you should pick a particular git commit and use that. Go modules can be useful for this purpose.

adapter_ninafw.go

@@ -0,0 +1,209 @@
+//go:build ninafw
+
+package bluetooth
+
+import (
+	"machine"
+	"runtime"
+
+	"time"
+)
+
+const maxConnections = 1
+
+// Adapter represents the UART connection to the NINA fw.
+type Adapter struct {
+	hci *hci
+	att *att
+
+	isDefault bool
+	scanning  bool
+
+	reset          func()
+	connectHandler func(device Address, connected bool)
+
+	connectedDevices     []*Device
+	notificationsStarted bool
+}
+
+// DefaultAdapter is the default adapter on the current system.
+//
+// Make sure to call Enable() before using it to initialize the adapter.
+var DefaultAdapter = &Adapter{
+	isDefault: true,
+	reset:     resetNINAInverted,
+	connectHandler: func(device Address, connected bool) {
+		return
+	},
+	connectedDevices: make([]*Device, 0, maxConnections),
+}
+
+// Enable configures the BLE stack. It must be called before any
+// Bluetooth-related calls (unless otherwise indicated).
+func (a *Adapter) Enable() error {
+	// reset the NINA in BLE mode
+	machine.NINA_CS.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.NINA_RESETN.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	machine.NINA_CS.Low()
+	a.reset()
+
+	// serial port for nina chip
+	uart := machine.UART1
+	uart.Configure(machine.UARTConfig{
+		TX:       machine.NINA_TX,
+		RX:       machine.NINA_RX,
+		BaudRate: 115200,
+		CTS:      machine.NINA_CTS,
+		RTS:      machine.NINA_RTS,
+	})
+
+	a.hci, a.att = newBLEStack(uart)
+
+	a.hci.start()
+
+	if err := a.hci.reset(); err != nil {
+		return err
+	}
+
+	time.Sleep(150 * time.Millisecond)
+
+	if err := a.hci.setEventMask(0x3FFFFFFFFFFFFFFF); err != nil {
+		return err
+	}
+
+	if err := a.hci.setLeEventMask(0x00000000000003FF); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (a *Adapter) Address() (MACAddress, error) {
+	if err := a.hci.readBdAddr(); err != nil {
+		return MACAddress{}, err
+	}
+
+	return MACAddress{MAC: makeAddress(a.hci.address)}, nil
+}
+
+func newBLEStack(uart *machine.UART) (*hci, *att) {
+	h := newHCI(uart)
+	a := newATT(h)
+	h.att = a
+
+	return h, a
+}
+
+// Convert a NINA MAC address into a Go MAC address.
+func makeAddress(mac [6]uint8) MAC {
+	return MAC{
+		uint8(mac[0]),
+		uint8(mac[1]),
+		uint8(mac[2]),
+		uint8(mac[3]),
+		uint8(mac[4]),
+		uint8(mac[5]),
+	}
+}
+
+// Convert a Go MAC address into a NINA MAC Address.
+func makeNINAAddress(mac MAC) [6]uint8 {
+	return [6]uint8{
+		uint8(mac[0]),
+		uint8(mac[1]),
+		uint8(mac[2]),
+		uint8(mac[3]),
+		uint8(mac[4]),
+		uint8(mac[5]),
+	}
+}
+
+func resetNINA() {
+	machine.NINA_RESETN.High()
+	time.Sleep(100 * time.Millisecond)
+	machine.NINA_RESETN.Low()
+	time.Sleep(1000 * time.Millisecond)
+}
+
+func resetNINAInverted() {
+	machine.NINA_RESETN.Low()
+	time.Sleep(100 * time.Millisecond)
+	machine.NINA_RESETN.High()
+	time.Sleep(1000 * time.Millisecond)
+}
+
+func (a *Adapter) startNotifications() {
+	if a.notificationsStarted {
+		return
+	}
+
+	if _debug {
+		println("starting notifications...")
+	}
+
+	a.notificationsStarted = true
+
+	// go routine to poll for HCI events for ATT notifications
+	go func() {
+		for {
+			if err := a.att.poll(); err != nil {
+				// TODO: handle error
+				if _debug {
+					println("error polling for notifications:", err.Error())
+				}
+			}
+
+			time.Sleep(250 * time.Millisecond)
+		}
+	}()
+
+	// go routine to handle characteristic notifications
+	go func() {
+		for {
+			select {
+			case not := <-a.att.notifications:
+				if _debug {
+					println("notification received", not.connectionHandle, not.handle, not.data)
+				}
+
+				d := a.findDevice(not.connectionHandle)
+				if d == nil {
+					if _debug {
+						println("no device found for handle", not.connectionHandle)
+					}
+					continue
+				}
+
+				n := d.findNotificationRegistration(not.handle)
+				if n == nil {
+					if _debug {
+						println("no notification registered for handle", not.handle)
+					}
+					continue
+				}
+
+				if n.callback != nil {
+					n.callback(not.data)
+				}
+
+			default:
+			}
+
+			runtime.Gosched()
+		}
+	}()
+}
+
+func (a *Adapter) findDevice(handle uint16) *Device {
+	for _, d := range a.connectedDevices {
+		if d.handle == handle {
+			if _debug {
+				println("found device", handle, d.Address.String(), "with notifications registered", len(d.notificationRegistrations))
+			}
+
+			return d
+		}
+	}
+
+	return nil
+}