bluetooth-fw: remove GATT MTU service

This service is no longer useful nor applicable on modern devices.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>

docs/legacy/porting-bluetooth.md

@@ -86,7 +86,6 @@ See at least one implementation:
 https://github.com/pebble-dev/RebbleOS/blob/master/hw/drivers/nrf52_bluetooth/nrf52_bluetooth_ppogatt.c#L352-L417
 
 * bt_driver_pebble_pairing_service_handle_status_change
-* bt_driver_pebble_pairing_service_handle_gatt_mtu_change
 * bt_driver_cb_pebble_pairing_service_handle_connection_parameter_write
 * bt_driver_cb_pebble_pairing_service_handle_ios_app_termination_detected
 

src/bluetooth-fw/nimble/pebble_pairing_service.c

@@ -119,12 +119,6 @@ static int prv_access_trigger_pairing(uint16_t conn_handle, uint16_t attr_handle
   return 0;
 }
 
-static int prv_access_gatt_mtu(uint16_t conn_handle, uint16_t attr_handle,
-                               struct ble_gatt_access_ctxt *ctxt, void *arg) {
-  // TODO: implement
-  return 0;
-}
-
 static const struct ble_gatt_svc_def pebble_pairing_svc[] = {
     {
         .type = BLE_GATT_SVC_TYPE_PRIMARY,
@@ -143,12 +137,6 @@ static const struct ble_gatt_svc_def pebble_pairing_svc[] = {
                     .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_WRITE,
                     .access_cb = prv_access_trigger_pairing,
                 },
-                {
-                    .uuid = BLE_UUID128_DECLARE(
-                        BLE_UUID_SWIZZLE(PEBBLE_BT_PAIRING_SERVICE_GATT_MTU_UUID)),
-                    .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_WRITE | BLE_GATT_CHR_F_NOTIFY,
-                    .access_cb = prv_access_gatt_mtu,
-                },
                 {
                     0, /* No more characteristics in this service */
                 },
@@ -193,8 +181,3 @@ void bt_driver_pebble_pairing_service_handle_status_change(const GAPLEConnection
       connection,
       BLE_UUID128_DECLARE(BLE_UUID_SWIZZLE(PEBBLE_BT_PAIRING_SERVICE_CONNECTION_STATUS_UUID)));
 }
-
-void bt_driver_pebble_pairing_service_handle_gatt_mtu_change(const GAPLEConnection *connection) {
-  prv_notify_chr_updated(
-      connection, BLE_UUID128_DECLARE(BLE_UUID_SWIZZLE(PEBBLE_BT_PAIRING_SERVICE_GATT_MTU_UUID)));
-}

src/bluetooth-fw/qemu/pebble_pairing_service.c

@@ -18,6 +18,3 @@
 
 void bt_driver_pebble_pairing_service_handle_status_change(const GAPLEConnection *connection) {
 }
-
-void bt_driver_pebble_pairing_service_handle_gatt_mtu_change(const GAPLEConnection *connection) {
-}

src/bluetooth-fw/stub/pebble_pairing_service.c

@@ -18,6 +18,3 @@
 
 void bt_driver_pebble_pairing_service_handle_status_change(const GAPLEConnection *connection) {
 }
-
-void bt_driver_pebble_pairing_service_handle_gatt_mtu_change(const GAPLEConnection *connection) {
-}

src/fw/comm/ble/gatt.c

@@ -76,7 +76,6 @@ void bt_driver_cb_gatt_handle_mtu_update(const GattDeviceMtuUpdateEvent *event)
             connection->gatt_mtu, event->mtu);
     if (has_mtu_changed) {
       connection->gatt_mtu = event->mtu;
-      bt_driver_pebble_pairing_service_handle_gatt_mtu_change(connection);
     }
     BLE_LOG_DEBUG("GATT MTU Updated: remote: %u", event->mtu);
   }

src/include/bluetooth/pebble_pairing_service.h

@@ -22,7 +22,6 @@
 
 #define PEBBLE_BT_PAIRING_SERVICE_CONNECTION_STATUS_UUID PEBBLE_BT_UUID_EXPAND(1)
 #define PEBBLE_BT_PAIRING_SERVICE_TRIGGER_PAIRING_UUID PEBBLE_BT_UUID_EXPAND(2)
-#define PEBBLE_BT_PAIRING_SERVICE_GATT_MTU_UUID PEBBLE_BT_UUID_EXPAND(3)
 // Note: UUID 4 was used by the 3.14-rc Android App for V0 of the Connection Param characteristic
 // but never shipped externally
 #define PEBBLE_BT_PAIRING_SERVICE_CONNECTION_PARAMETERS_UUID PEBBLE_BT_UUID_EXPAND(5)
@@ -226,12 +225,6 @@ typedef struct GAPLEConnection GAPLEConnection;
 //! @param connection The connection for which the status was changed.
 void bt_driver_pebble_pairing_service_handle_status_change(const GAPLEConnection *connection);
 
-//! Signals to the Pebble GATT service the GATT MTU has changed, allowing it to notify any BLE
-//! devices that are subscribed to GATT MTU characteristic.
-//! @param connection The connection for which the GATT MTU has changed.
-//! @note the caller is responsible for taking bt_lock!
-void bt_driver_pebble_pairing_service_handle_gatt_mtu_change(const GAPLEConnection *connection);
-
 //! Indicate to the FW that Connectivity Status characteristic has been unsubscribed from.
 //! This is used to detect that the Pebble iOS app has been terminated.
 extern void bt_driver_cb_pebble_pairing_service_handle_ios_app_termination_detected(void);