Add AT commands to switch between BLE, Classic BT/A2DP, and Bluetooth off

src/bt.c

@@ -11,6 +11,7 @@
 #include "esp_err.h"
 #include "esp_log.h"
 #include "freertos/task.h"
+#include "sdkconfig.h"
 
 
 #define LOG_BT "BT"
@@ -40,11 +41,22 @@ char *btaddrtostr(char dest[13], esp_bd_addr_t src)
 
 bool memreleased = false;
 
-void bt_init()
+// Classic BT/A2DP needs the controller's Classic memory, which can't be recovered once released
+// (until reboot). Only release it in builds that can't use Classic BT anyway.
+bool bt_a2dp_supported()
+{
+#if defined(CONFIG_BT_CLASSIC_ENABLED) && defined(CONFIG_BT_A2DP_ENABLE)
+  return true;
+#else
+  return false;
+#endif
+}
+
+static void bt_start_stack(esp_bt_mode_t mode)
 {
   esp_err_t ret;
 
-  if (!memreleased) {
+  if (!memreleased && !bt_a2dp_supported()) {
     ESP_ERROR_CHECK(esp_bt_controller_mem_release(ESP_BT_MODE_CLASSIC_BT));
     memreleased = true;
   }
@@ -56,7 +68,7 @@ void bt_init()
     return;
   }
 
-  ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
+  ret = esp_bt_controller_enable(mode);
   if (ret) {
     ESP_LOGE(LOG_BT, "%s enable controller failed: %s\n", __func__, esp_err_to_name(ret));
     return;
@@ -74,7 +86,20 @@ void bt_init()
     return;
   }
 
-  esp_ble_tx_power_set(ESP_BLE_PWR_TYPE_DEFAULT, ESP_PWR_LVL_P9);
+  if (mode == ESP_BT_MODE_BLE) esp_ble_tx_power_set(ESP_BLE_PWR_TYPE_DEFAULT, ESP_PWR_LVL_P9);
+}
+
+void bt_init()
+{
+  ESP_LOGI(LOG_BT, "Starting BLE stack");
+  bt_start_stack(ESP_BT_MODE_BLE);
+}
+
+// Note: BLE and Classic BT are never run together, the stack is restarted when switching.
+void bt_classic_init()
+{
+  ESP_LOGI(LOG_BT, "Starting Classic BT stack");
+  bt_start_stack(ESP_BT_MODE_CLASSIC_BT);
 }
 
 void bt_disable()

src/bt.h

@@ -17,4 +17,6 @@ void strtobtaddr(esp_bd_addr_t dest, char *src);
 char *btaddrtostr(char dest[13], esp_bd_addr_t src);
 void bt_disable();
 void bt_init();
+void bt_classic_init();
+bool bt_a2dp_supported();
 void btSetName(const char *name);

src/bt_a2dp.c

@@ -0,0 +1,71 @@
+/* Bluetooth Classic A2DP Source - minimal initialization/shutdown path
+ * Streaming is stubbed, silence is sent until audio is fed from the UART.
+ */
+
+#include "bt_a2dp.h"
+
+#include <string.h>
+
+#include "bt.h"
+#include "esp_log.h"
+#include "sdkconfig.h"
+
+#define LOG_A2DP "A2DP"
+
+#if defined(CONFIG_BT_CLASSIC_ENABLED) && defined(CONFIG_BT_A2DP_ENABLE)
+
+#include "esp_a2dp_api.h"
+#include "esp_bt_device.h"
+#include "esp_gap_bt_api.h"
+
+static int32_t a2dpDataCb(uint8_t *data, int32_t len)
+{
+  if (data == NULL || len < 0) return 0;
+  memset(data, 0, len);  // Silence
+  return len;
+}
+
+static void a2dpEventCb(esp_a2d_cb_event_t event, esp_a2d_cb_param_t *param)
+{
+  if (event == ESP_A2D_CONNECTION_STATE_EVT) {
+    ESP_LOGI(LOG_A2DP, "Connection state %d", param->conn_stat.state);
+  }
+}
+
+bool a2dpInit()
+{
+  esp_bt_dev_set_device_name(btname);
+  esp_bt_gap_set_scan_mode(ESP_BT_CONNECTABLE, ESP_BT_GENERAL_DISCOVERABLE);
+  if (esp_a2d_register_callback(a2dpEventCb) != ESP_OK ||
+      esp_a2d_source_register_data_cb(a2dpDataCb) != ESP_OK ||
+      esp_a2d_source_init() != ESP_OK) {
+    ESP_LOGE(LOG_A2DP, "A2DP source init failed");
+    return false;
+  }
+  return true;
+}
+
+void a2dpDeinit()
+{
+  esp_a2d_source_deinit();
+}
+
+void a2dpConnect(const char *addr)
+{
+  esp_bd_addr_t bda;
+  if (strlen(addr) < 12) return;
+  strtobtaddr(bda, (char *)addr);
+  esp_a2d_source_connect(bda);
+}
+
+#else
+
+bool a2dpInit()
+{
+  ESP_LOGE(LOG_A2DP, "A2DP not supported in this build (needs CONFIG_BT_CLASSIC_ENABLED/A2DP)");
+  return false;
+}
+void a2dpDeinit() {}
+void a2dpConnect(const char *addr) {}
+
+#endif

src/bt_a2dp.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <stdbool.h>
+
+// Minimal Bluetooth Classic A2DP source. Audio streaming is stubbed (silence).
+// Call after bt_classic_init().
+bool a2dpInit();
+void a2dpDeinit();
+void a2dpConnect(const char *addr);

src/defines.h

@@ -58,6 +58,8 @@ typedef enum {
   ROLE_BLE_PERIPHERAL,
   ROLE_BLE_CENTRAL,
   ROLE_ADVANCE,
+  ROLE_BTEDR_AUDIO_SOURCE,  // Bluetooth Classic A2DP source (BLE is off in this mode)
+  ROLE_BT_OFF,              // All Bluetooth stacks off
   ROLE_COUNT
 } role_t;
 

src/terminal.c

@@ -6,6 +6,7 @@
 #include <nvs.h>
 
 #include "bt.h"
+#include "bt_a2dp.h"
 #include "bt_client.h"
 #include "bt_server.h"
 #include "cb.h"
@@ -47,6 +48,7 @@ typedef enum {
 } btperipheralstate;
 
 role_t curMode = ROLE_UNKNOWN;
+role_t lastBleRole = ROLE_UNKNOWN;
 btcentralstate btCentralState = CENTRAL_STATE_DISCONNECT;
 btperipheralstate btPeripherialState = PERIPHERIAL_STATE_DISCONNECTED;
 int64_t baudTimer = 0;
@@ -55,6 +57,22 @@ int laddcnt = 0;
 char rmtaddress[13] = "000000000000";
 char reusablebuff[REUSABLE_BUFFER];
 
+const char *roleName(role_t role)
+{
+  switch (role) {
+    case ROLE_BLE_PERIPHERAL:
+      return "BLE Peripheral";
+    case ROLE_BLE_CENTRAL:
+      return "BLE Central";
+    case ROLE_BTEDR_AUDIO_SOURCE:
+      return "A2DP Source";
+    case ROLE_BT_OFF:
+      return "Bluetooth Off";
+    default:
+      return "Unknown";
+  }
+}
+
 void sendBTMode()
 {
   char lcladdress[13] = "000000000000";
@@ -66,6 +84,9 @@ void sendBTMode()
   } else if (curMode == ROLE_BLE_CENTRAL) {
     snprintf(reusablebuff, sizeof(reusablebuff), "Central:%s\r\n", lcladdress);
     uart_write_bytes(uart_num, reusablebuff, strlen(reusablebuff));
+  } else {
+    snprintf(reusablebuff, sizeof(reusablebuff), "Mode:%s\r\n", roleName(curMode));
+    uart_write_bytes(uart_num, reusablebuff, strlen(reusablebuff));
   }
 }
 
@@ -147,6 +168,60 @@ void parserATCommand(char atcommand[])
     // before an AT+ACK or something is seen. Then revert back to the default
     // baud
 
+  } else if (strncmp(atcommand, "+BLEON", 6) == 0) {
+    // Re-enable BLE, using the last BLE role (central by default)
+    role_t r = ROLE_BLE_CENTRAL;
+    if (curMode == ROLE_BLE_PERIPHERAL || curMode == ROLE_BLE_CENTRAL)
+      r = curMode;
+    else if (lastBleRole != ROLE_UNKNOWN)
+      r = lastBleRole;
+    UART_WRITE_STRING(uart_num, "OK+BLEON\r\n");
+    setRole(r);
+    sendBTMode();
+
+  } else if (strncmp(atcommand, "+BLEOFF", 7) == 0) {
+    UART_WRITE_STRING(uart_num, "OK+BLEOFF\r\n");
+    if (curMode == ROLE_BLE_PERIPHERAL || curMode == ROLE_BLE_CENTRAL) {
+      setRole(ROLE_BT_OFF);
+      sendBTMode();
+    }
+
+  } else if (strncmp(atcommand, "+A2DPON", 7) == 0) {
+    if (bt_a2dp_supported()) {
+      // BLE and Classic BT can't run together, BLE is stopped first
+      UART_WRITE_STRING(uart_num, "OK+A2DPON\r\n");
+      setRole(ROLE_BTEDR_AUDIO_SOURCE);
+      sendBTMode();
+    } else {
+      ESP_LOGE(LOG_UART, "A2DP not supported in this build");
+      UART_WRITE_STRING(uart_num, "ERROR\r\n");
+    }
+
+  } else if (strncmp(atcommand, "+A2DPOFF", 8) == 0) {
+    UART_WRITE_STRING(uart_num, "OK+A2DPOFF\r\n");
+    if (curMode == ROLE_BTEDR_AUDIO_SOURCE) {
+      setRole(ROLE_BT_OFF);
+      sendBTMode();
+    }
+
+  } else if (strncmp(atcommand, "+A2DPCON", 8) == 0) {
+    if (curMode == ROLE_BTEDR_AUDIO_SOURCE) {
+      UART_WRITE_STRING(uart_num, "OK+A2DPCON\r\n");
+      a2dpConnect(atcommand + 8);
+    } else {
+      UART_WRITE_STRING(uart_num, "ERROR\r\n");
+    }
+
+  } else if (strncmp(atcommand, "+BTOFF", 6) == 0) {
+    UART_WRITE_STRING(uart_num, "OK+BTOFF\r\n");
+    setRole(ROLE_BT_OFF);
+    sendBTMode();
+
+  } else if (strncmp(atcommand, "+BTBOTH", 7) == 0) {
+    // Simultaneous BLE + A2DP isn't supported by this configuration (RAM/coexistence)
+    ESP_LOGE(LOG_UART, "BLE + A2DP at the same time is not supported");
+    UART_WRITE_STRING(uart_num, "ERROR\r\n");
+
   } else if (strncmp(atcommand, "+HTRESET", 8) == 0) {
     if (btc_board_type == BLE_BOARD_HEADTRACKER) {
       ESP_LOGI(LOG_UART, "Reset Head Tracker Requested");
@@ -204,6 +279,10 @@ void runUARTHead()
     ESP_LOGE(LOG_UART, "Invalid role loaded, defaulting to central");
     settings.role = ROLE_BLE_CENTRAL;
   }
+  if (settings.role == ROLE_BTEDR_AUDIO_SOURCE && !bt_a2dp_supported()) {
+    ESP_LOGE(LOG_UART, "A2DP not supported in this build, defaulting to central");
+    settings.role = ROLE_BLE_CENTRAL;
+  }
   setRole(settings.role);
 
   char* data = (char*)malloc(UART_RX_BUFFER + 1);
@@ -238,7 +317,7 @@ void runUARTHead()
         static char lc = 0;
         if (lc == 'A' && c == 'T') {
           atcommandlen = 0;
-        } else {
+        } else if (curMode == ROLE_BLE_CENTRAL || curMode == ROLE_BLE_PERIPHERAL) {
           frSkyProcessByte(c);
         }
 
@@ -262,14 +341,24 @@ void setRole(role_t role)
   switch (curMode) {
     case ROLE_BLE_CENTRAL:
     case ROLE_BLE_PERIPHERAL:
+      lastBleRole = curMode;
+      bt_disable();
+      break;
+    case ROLE_BTEDR_AUDIO_SOURCE:
+      a2dpDeinit();
       bt_disable();
+      break;
     default:
       break;
   }
 
+  // Drop any partially received AT command so stale parsing state isn't carried over
+  atcommandlen = -1;
+
   // Update Role
   curMode = role;
   settings.role = curMode;
+  ESP_LOGI(LOG_UART, "Active Bluetooth mode: %s", roleName(curMode));
 
   // Initialize
   switch (curMode) {
@@ -283,6 +372,16 @@ void setRole(role_t role)
       bt_init();
       btpInit();
       break;
+    case ROLE_BTEDR_AUDIO_SOURCE:
+      bt_classic_init();
+      if (!a2dpInit()) {
+        a2dpDeinit();
+        bt_disable();
+        curMode = ROLE_BT_OFF;
+        settings.role = curMode;
+        ESP_LOGE(LOG_UART, "A2DP start failed, Bluetooth is off");
+      }
+      break;
     default:
       break;
   }