DFUService.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __BLE_DFU_SERVICE_H__
00018 #define __BLE_DFU_SERVICE_H__
00019 
00020 #include "ble/BLE.h"
00021 #include "ble/UUID.h"
00022 
00023 extern "C" {
00024 #include "dfu_app_handler.h"
00025 }
00026 
00027 extern const uint8_t  DFUServiceBaseUUID[];
00028 extern const uint16_t DFUServiceShortUUID;
00029 extern const uint16_t DFUServiceControlCharacteristicShortUUID;
00030 
00031 extern const uint8_t  DFUServiceUUID[];
00032 extern const uint8_t  DFUServiceControlCharacteristicUUID[];
00033 extern const uint8_t  DFUServicePacketCharacteristicUUID[];
00034 
00035 /**
00036 * @class DFUService
00037 * @brief Device Firmware Update Service.
00038 */
00039 class DFUService {
00040 public:
00041     /**
00042      * @brief Signature for the handover callback. The application may provide this
00043      * callback when setting up the DFU service. The callback is then
00044      * invoked before handing control over to the bootloader.
00045      */
00046     typedef void (*ResetPrepare_t)(void);
00047 
00048 public:
00049     /**
00050     * @brief Adds Device Firmware Update Service to an existing BLE object.
00051     *
00052     * @param[ref] _ble
00053     *               BLE object for the underlying controller.
00054     * @param[in] _handoverCallback
00055     *                Application-specific handover callback.
00056     */
00057     DFUService(BLE &_ble, ResetPrepare_t _handoverCallback = NULL) :
00058         ble(_ble),
00059         controlPoint(DFUServiceControlCharacteristicUUID, controlBytes, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
00060         packet(DFUServicePacketCharacteristicUUID, packetBytes, SIZEOF_PACKET_BYTES, SIZEOF_PACKET_BYTES,
00061                GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE),
00062         controlBytes(),
00063         packetBytes() {
00064         static bool serviceAdded = false; /* We only add the DFU service once. */
00065         if (serviceAdded) {
00066             return;
00067         }
00068 
00069         /* Set an initial value for control bytes, so that the application's DFU service can
00070          * be distinguished from the real DFU service provided by the bootloader. */
00071         controlBytes[0] = 0xFF;
00072         controlBytes[1] = 0xFF;
00073 
00074         GattCharacteristic *dfuChars[] = {&controlPoint, &packet};
00075         GattService         dfuService(DFUServiceUUID, dfuChars, sizeof(dfuChars) / sizeof(GattCharacteristic *));
00076 
00077         ble.addService(dfuService);
00078         handoverCallback = _handoverCallback;
00079         serviceAdded     = true;
00080 
00081         ble.onDataWritten(this, &DFUService::onDataWritten);
00082     }
00083 
00084     /**
00085     * @brief Get the handle for the value attribute of the control characteristic.
00086     */
00087     uint16_t getControlHandle(void) const {
00088         return controlPoint.getValueHandle();
00089     }
00090 
00091     /**
00092      * @brief This callback allows the DFU service to receive the initial trigger to
00093      * hand control over to the bootloader. First, the application is given a
00094      * chance to clean up.
00095      *
00096      * @param[in] params
00097      *     Information about the characterisitc being updated.
00098      */
00099     virtual void onDataWritten(const GattWriteCallbackParams *params) {
00100         if (params->handle == controlPoint.getValueHandle()) {
00101             /* At present, writing anything will do the trick - this needs to be improved. */
00102             if (handoverCallback) {
00103                 handoverCallback();
00104             }
00105 
00106             // Call bootloader_start implicitly trough a event handler call
00107             // it is a work around for bootloader_start not being public in sdk 8.1
00108             ble_dfu_t p_dfu;
00109             ble_dfu_evt_t p_evt;
00110 
00111             p_dfu.conn_handle = params->connHandle;
00112             p_evt.ble_dfu_evt_type = BLE_DFU_START;
00113 
00114             dfu_app_on_dfu_evt(&p_dfu, &p_evt);
00115         }
00116     }
00117 
00118 protected:
00119     static const unsigned SIZEOF_CONTROL_BYTES = 2;
00120     static const unsigned SIZEOF_PACKET_BYTES  = 20;
00121 
00122 protected:
00123     BLE          &ble;
00124 
00125     /**< Writing to the control characteristic triggers the handover to DFU 
00126       *  bootloader. At present, writing anything will do the trick - this needs
00127       *  to be improved. */
00128     WriteOnlyArrayGattCharacteristic<uint8_t, SIZEOF_CONTROL_BYTES> controlPoint;
00129 
00130     /**< The packet characteristic in this service doesn't do anything meaningful;
00131       *  it is only a placeholder to mimic the corresponding characteristic in the
00132       *  actual DFU service implemented by the bootloader. Without this, some
00133       *  FOTA clients might get confused, because service definitions change after
00134       *  handing control over to the bootloader. */
00135     GattCharacteristic  packet;
00136 
00137     uint8_t             controlBytes[SIZEOF_CONTROL_BYTES];
00138     uint8_t             packetBytes[SIZEOF_PACKET_BYTES];
00139 
00140     static ResetPrepare_t handoverCallback;  /**< Application-specific handover callback. */
00141 };
00142 
00143 #endif /* #ifndef __BLE_DFU_SERVICE_H__*/