Add skeleton of bluetooth FSM

src/drivers/CMakeLists.txt

@@ -7,5 +7,5 @@ idf_component_register(
   "spi.cpp" "display.cpp" "display_init.cpp" "samd.cpp" "relative_wheel.cpp" "wm8523.cpp"
   "nvs.cpp" "bluetooth.cpp"
   INCLUDE_DIRS "include"
-  REQUIRES "esp_adc" "fatfs" "result" "lvgl" "span" "tasks" "nvs_flash" "bt")
+  REQUIRES "esp_adc" "fatfs" "result" "lvgl" "span" "tasks" "nvs_flash" "bt" "tinyfsm")
 target_compile_options(${COMPONENT_LIB} PRIVATE ${EXTRA_WARNINGS})

src/drivers/bluetooth.cpp

@@ -1,11 +1,253 @@
 #include "bluetooth.hpp"
 
+#include <stdint.h>
+
+#include <atomic>
+#include <ostream>
+#include <sstream>
+
+#include "esp_a2dp_api.h"
+#include "esp_avrc_api.h"
 #include "esp_bt.h"
+#include "esp_bt_device.h"
+#include "esp_bt_main.h"
+#include "esp_gap_bt_api.h"
+#include "esp_log.h"
+#include "esp_mac.h"
+#include "tinyfsm/include/tinyfsm.hpp"
 
 namespace drivers {
 
-auto Bluetooth::Enable() -> Bluetooth* {
+static constexpr char kTag[] = "bluetooth";
-  return nullptr;
+
+static std::atomic<StreamBufferHandle_t> sStream;
+
+auto gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t* param) -> void {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::dispatch(
+      bluetooth::events::internal::Gap{.type = event, .param = param});
+}
+
+auto avrcp_cb(esp_avrc_ct_cb_event_t event, esp_avrc_ct_cb_param_t* param)
+    -> void {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::dispatch(
+      bluetooth::events::internal::Avrc{.type = event, .param = param});
+}
+
+auto a2dp_cb(esp_a2d_cb_event_t event, esp_a2d_cb_param_t* param) -> void {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::dispatch(
+      bluetooth::events::internal::A2dp{.type = event, .param = param});
+}
+
+auto a2dp_data_cb(uint8_t* buf, int32_t buf_size) -> int32_t {
+  if (buf == nullptr || buf_size <= 0) {
+    return 0;
+  }
+  StreamBufferHandle_t stream = sStream.load();
+  if (stream == nullptr) {
+    return 0;
+  }
+  return xStreamBufferReceive(stream, buf, buf_size, 0);
+}
+
+Bluetooth::Bluetooth() {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::start();
+}
+
+auto Bluetooth::Enable() -> bool {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::dispatch(
+      bluetooth::events::Enable{});
+
+  return !bluetooth::BluetoothState::is_in_state<bluetooth::Disabled>();
+}
+
+auto Bluetooth::Disable() -> void {
+  tinyfsm::FsmList<bluetooth::BluetoothState>::dispatch(
+      bluetooth::events::Disable{});
+}
+
+auto DeviceName() -> std::string {
+  uint8_t mac[8]{0};
+  esp_efuse_mac_get_default(mac);
+  std::ostringstream name;
+  name << "TANGARA " << std::hex << mac[0] << mac[1];
+  return name.str();
+}
+
+namespace bluetooth {
+
+static bool sIsFirstEntry = true;
+
+void Disabled::entry() {
+  if (sIsFirstEntry) {
+    // We only use BT Classic, to claw back ~60KiB from the BLE firmware.
+    esp_bt_controller_mem_release(ESP_BT_MODE_BLE);
+    sIsFirstEntry = false;
+    return;
+  }
+
+  esp_bluedroid_disable();
+  esp_bluedroid_deinit();
+  esp_bt_controller_disable();
+}
+
+void Disabled::react(const events::Enable&) {
+  esp_bt_controller_config_t config = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
+  if (esp_bt_controller_init(&config) != ESP_OK) {
+    ESP_LOGE(kTag, "initialize controller failed");
+    return;
+  }
+
+  if (esp_bt_controller_enable(ESP_BT_MODE_CLASSIC_BT) != ESP_OK) {
+    ESP_LOGE(kTag, "enable controller failed");
+    return;
+  }
+
+  if (esp_bluedroid_init() != ESP_OK) {
+    ESP_LOGE(kTag, "initialize bluedroid failed");
+    return;
+  }
+
+  if (esp_bluedroid_enable() != ESP_OK) {
+    ESP_LOGE(kTag, "enable bluedroid failed");
+    return;
+  }
+
+  // Enable Secure Simple Pairing
+  esp_bt_sp_param_t param_type = ESP_BT_SP_IOCAP_MODE;
+  esp_bt_io_cap_t iocap = ESP_BT_IO_CAP_IO;
+  esp_bt_gap_set_security_param(param_type, &iocap, sizeof(uint8_t));
+
+  // Set a reasonable name for the device.
+  std::string name = DeviceName();
+  esp_bt_dev_set_device_name(name.c_str());
+
+  // Initialise GAP. This controls advertising our device, and scanning for
+  // other devices.
+  esp_bt_gap_register_callback(gap_cb);
+
+  // Initialise AVRCP. This handles playback controls; play/pause/volume/etc.
+  // esp_avrc_ct_init();
+  // esp_avrc_ct_register_callback(avrcp_cb);
+
+  // Initialise A2DP. This handles streaming audio. Currently ESP-IDF's SBC
+  // encoder only supports 2 channels of interleaved 16 bit samples, at
+  // 44.1kHz, so there is no additional configuration to be done for the
+  // stream itself.
+  esp_a2d_source_init();
+  esp_a2d_register_callback(a2dp_cb);
+  esp_a2d_source_register_data_callback(a2dp_data_cb);
+
+  // Don't let anyone interact with us before we're ready.
+  esp_bt_gap_set_scan_mode(ESP_BT_NON_CONNECTABLE, ESP_BT_NON_DISCOVERABLE);
+
+  transit<Scanning>();
 }
 
+static constexpr uint8_t kDiscoveryTimeSeconds = 10;
+static constexpr uint8_t kDiscoveryMaxResults = 0;
+
+void Scanning::entry() {
+  ESP_LOGI(kTag, "scanning for devices");
+  esp_bt_gap_start_discovery(ESP_BT_INQ_MODE_GENERAL_INQUIRY,
+                             kDiscoveryTimeSeconds, kDiscoveryMaxResults);
+}
+
+void Scanning::exit() {
+  esp_bt_gap_cancel_discovery();
+}
+
+auto OnDeviceDiscovered(esp_bt_gap_cb_param_t* param) -> void {
+  ESP_LOGI(kTag, "device discovered");
+}
+
+void Scanning::react(const events::internal::Gap& ev) {
+  switch (ev.type) {
+    case ESP_BT_GAP_DISC_RES_EVT:
+      OnDeviceDiscovered(ev.param);
+      break;
+    case ESP_BT_GAP_DISC_STATE_CHANGED_EVT:
+      if (ev.param->disc_st_chg.state == ESP_BT_GAP_DISCOVERY_STOPPED) {
+        ESP_LOGI(kTag, "still scanning");
+        esp_bt_gap_start_discovery(ESP_BT_INQ_MODE_GENERAL_INQUIRY,
+                                   kDiscoveryTimeSeconds, kDiscoveryMaxResults);
+      }
+      break;
+    case ESP_BT_GAP_MODE_CHG_EVT:
+      // todo: mode change. is this important?
+      ESP_LOGI(kTag, "GAP mode changed");
+      break;
+    default:
+      ESP_LOGW(kTag, "unhandled GAP event: %u", ev.type);
+  }
+}
+
+void Connecting::entry() {
+  ESP_LOGI(kTag, "connecting to device");
+  esp_a2d_source_connect(nullptr);
+}
+
+void Connecting::exit() {}
+
+void Connecting::react(const events::internal::Gap& ev) {
+  switch (ev.type) {
+    case ESP_BT_GAP_AUTH_CMPL_EVT:
+      // todo: auth completed. check if we succeeded.
+      break;
+    case ESP_BT_GAP_PIN_REQ_EVT:
+      // todo: device needs a pin to connect.
+      break;
+    case ESP_BT_GAP_CFM_REQ_EVT:
+      // todo: device needs user to click okay.
+      break;
+    case ESP_BT_GAP_KEY_NOTIF_EVT:
+      // todo: device is telling us a password?
+      break;
+    case ESP_BT_GAP_KEY_REQ_EVT:
+      // todo: device needs a password
+      break;
+    case ESP_BT_GAP_MODE_CHG_EVT:
+      // todo: mode change. is this important?
+      break;
+    default:
+      ESP_LOGW(kTag, "unhandled GAP event: %u", ev.type);
+  }
+}
+
+void Connecting::react(const events::internal::A2dp& ev) {
+  switch (ev.type) {
+    case ESP_A2D_CONNECTION_STATE_EVT:
+      // todo: connection state changed. we might be connected!
+      break;
+    default:
+      ESP_LOGW(kTag, "unhandled A2DP event: %u", ev.type);
+  }
+}
+
+void Connected::react(const events::internal::A2dp& ev) {
+  switch (ev.type) {
+    case ESP_A2D_CONNECTION_STATE_EVT:
+      // todo: connection state changed. we might have dropped
+      break;
+    case ESP_A2D_AUDIO_STATE_EVT:
+      // todo: audio state changed. who knows, dude.
+      break;
+    default:
+      ESP_LOGW(kTag, "unhandled A2DP event: %u", ev.type);
+  }
+}
+
+void Connected::react(const events::internal::Avrc& ev) {
+  switch (ev.type) {
+    case ESP_AVRC_CT_CONNECTION_STATE_EVT:
+      // todo: avrc connected. send our capabilities.
+    default:
+      ESP_LOGW(kTag, "unhandled AVRC event: %u", ev.type);
+  }
+}
+
+}  // namespace bluetooth
+
 }  // namespace drivers
+
+FSM_INITIAL_STATE(drivers::bluetooth::BluetoothState,
+                  drivers::bluetooth::Disabled)

src/drivers/include/bluetooth.hpp

@@ -1,20 +1,108 @@
 
 #pragma once
 
+#include <string>
 #include <vector>
 
+#include <freertos/FreeRTOS.h>
+#include <freertos/stream_buffer.h>
+#include "esp_a2dp_api.h"
+#include "esp_avrc_api.h"
+#include "esp_gap_bt_api.h"
+#include "tinyfsm.hpp"
+#include "tinyfsm/include/tinyfsm.hpp"
+
 namespace drivers {
 
+/*
+ * A handle used to interact with the bluetooth state machine.
+ */
 class Bluetooth {
  public:
-  static auto Enable() -> Bluetooth*;
   Bluetooth();
-  ~Bluetooth();
 
-  struct Device {};
+  auto Enable() -> bool;
-  auto Scan() -> std::vector<Device>;
+  auto Disable() -> void;
+
+  auto SetSource(StreamBufferHandle_t) -> void;
+};
+
+namespace bluetooth {
+
+namespace events {
+struct Enable : public tinyfsm::Event {};
+struct Disable : public tinyfsm::Event {};
+
+namespace internal {
+struct Gap : public tinyfsm::Event {
+  esp_bt_gap_cb_event_t type;
+  esp_bt_gap_cb_param_t* param;
+};
+struct A2dp : public tinyfsm::Event {
+  esp_a2d_cb_event_t type;
+  esp_a2d_cb_param_t* param;
+};
+struct Avrc : public tinyfsm::Event {
+  esp_avrc_ct_cb_event_t type;
+  esp_avrc_ct_cb_param_t* param;
+};
+}  // namespace internal
+}  // namespace events
+
+class BluetoothState : public tinyfsm::Fsm<BluetoothState> {
+ public:
+  virtual ~BluetoothState(){};
+
+  virtual void entry() {}
+  virtual void exit() {}
+
+  virtual void react(const events::Enable& ev){};
+  virtual void react(const events::Disable& ev) = 0;
+
+  virtual void react(const events::internal::Gap& ev) = 0;
+  virtual void react(const events::internal::A2dp& ev) = 0;
+  virtual void react(const events::internal::Avrc& ev){};
+};
+
+class Disabled : public BluetoothState {
+  void entry() override;
+
+  void react(const events::Enable& ev) override;
+  void react(const events::Disable& ev) override{};
+
+  void react(const events::internal::Gap& ev) override {}
+  void react(const events::internal::A2dp& ev) override {}
+};
+
+class Scanning : public BluetoothState {
+  void entry() override;
+  void exit() override;
+
+  void react(const events::Disable& ev) override;
 
- private:
+  void react(const events::internal::Gap& ev) override;
+  void react(const events::internal::A2dp& ev) override;
 };
 
+class Connecting : public BluetoothState {
+  void entry() override;
+  void exit() override;
+
+  void react(const events::Disable& ev) override;
+  void react(const events::internal::Gap& ev) override;
+  void react(const events::internal::A2dp& ev) override;
+};
+
+class Connected : public BluetoothState {
+  void entry() override;
+  void exit() override;
+
+  void react(const events::Disable& ev) override;
+  void react(const events::internal::Gap& ev) override;
+  void react(const events::internal::A2dp& ev) override;
+  void react(const events::internal::Avrc& ev) override;
+};
+
+}  // namespace bluetooth
+
 }  // namespace drivers