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 #ifdef TARGET_NRF51822 /* DFU only supported on nrf51 platforms */
00018 
00019 #ifndef __BLE_DFU_SERVICE_H__
00020 #define __BLE_DFU_SERVICE_H__
00021 
00022 #include "ble/BLE.h"
00023 #include "ble/UUID.h"
00024 
00025 extern "C" {
00026 #include "dfu_app_handler.h"
00027 }
00028 
00029 extern const uint8_t  DFUServiceBaseUUID[];
00030 extern const uint16_t DFUServiceShortUUID;
00031 extern const uint16_t DFUServiceControlCharacteristicShortUUID;
00032 
00033 extern const uint8_t  DFUServiceUUID[];
00034 extern const uint8_t  DFUServiceControlCharacteristicUUID[];
00035 extern const uint8_t  DFUServicePacketCharacteristicUUID[];
00036 
00037 /**
00038 * @class DFUService
00039 * @brief Device Firmware Update Service.
00040 */
00041 class DFUService {
00042 public:
00043     /**
00044      * @brief Signature for the handover callback. The application may provide this
00045      * callback when setting up the DFU service. The callback is then
00046      * invoked before handing control over to the bootloader.
00047      */
00048     typedef void (*ResetPrepare_t)(void);
00049 
00050 public:
00051     /**
00052     * @brief Adds Device Firmware Update Service to an existing BLE object.
00053     *
00054     * @param[ref] _ble
00055     *               BLE object for the underlying controller.
00056     * @param[in] _handoverCallback
00057     *                Application-specific handover callback.
00058     */
00059     DFUService(BLE &_ble, ResetPrepare_t _handoverCallback = NULL) :
00060         ble(_ble),
00061         controlPoint(DFUServiceControlCharacteristicUUID, controlBytes, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
00062         packet(DFUServicePacketCharacteristicUUID, packetBytes, SIZEOF_PACKET_BYTES, SIZEOF_PACKET_BYTES,
00063                GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE),
00064         controlBytes(),
00065         packetBytes() {
00066         static bool serviceAdded = false; /* We only add the DFU service once. */
00067         if (serviceAdded) {
00068             return;
00069         }
00070 
00071         /* Set an initial value for control bytes, so that the application's DFU service can
00072          * be distinguished from the real DFU service provided by the bootloader. */
00073         controlBytes[0] = 0xFF;
00074         controlBytes[1] = 0xFF;
00075 
00076         GattCharacteristic *dfuChars[] = {&controlPoint, &packet};
00077         GattService         dfuService(DFUServiceUUID, dfuChars, sizeof(dfuChars) / sizeof(GattCharacteristic *));
00078 
00079         ble.addService(dfuService);
00080         handoverCallback = _handoverCallback;
00081         serviceAdded     = true;
00082 
00083         ble.onDataWritten(this, &DFUService::onDataWritten);
00084     }
00085 
00086     /**
00087     * @brief Get the handle for the value attribute of the control characteristic.
00088     */
00089     uint16_t getControlHandle(void) const {
00090         return controlPoint.getValueHandle();
00091     }
00092 
00093     /**
00094      * @brief This callback allows the DFU service to receive the initial trigger to
00095      * hand control over to the bootloader. First, the application is given a
00096      * chance to clean up.
00097      *
00098      * @param[in] params
00099      *     Information about the characterisitc being updated.
00100      */
00101     virtual void onDataWritten(const GattWriteCallbackParams *params) {
00102         if (params->handle == controlPoint.getValueHandle()) {
00103             /* At present, writing anything will do the trick - this needs to be improved. */
00104             if (handoverCallback) {
00105                 handoverCallback();
00106             }
00107 
00108             // Call bootloader_start implicitly trough a event handler call
00109             // it is a work around for bootloader_start not being public in sdk 8.1
00110             ble_dfu_t p_dfu;
00111             ble_dfu_evt_t p_evt;
00112 
00113             p_dfu.conn_handle = params->connHandle;
00114             p_evt.ble_dfu_evt_type = BLE_DFU_START;
00115 
00116             dfu_app_on_dfu_evt(&p_dfu, &p_evt);
00117         }
00118     }
00119 
00120 protected:
00121     static const unsigned SIZEOF_CONTROL_BYTES = 2;
00122     static const unsigned SIZEOF_PACKET_BYTES  = 20;
00123 
00124 protected:
00125     BLE          &ble;
00126 
00127     /**< Writing to the control characteristic triggers the handover to DFU 
00128       *  bootloader. At present, writing anything will do the trick - this needs
00129       *  to be improved. */
00130     WriteOnlyArrayGattCharacteristic<uint8_t, SIZEOF_CONTROL_BYTES>  controlPoint;
00131 
00132     /**< The packet characteristic in this service doesn't do anything meaningful;
00133       *  it is only a placeholder to mimic the corresponding characteristic in the
00134       *  actual DFU service implemented by the bootloader. Without this, some
00135       *  FOTA clients might get confused, because service definitions change after
00136       *  handing control over to the bootloader. */
00137     GattCharacteristic  packet;
00138 
00139     uint8_t             controlBytes[SIZEOF_CONTROL_BYTES];
00140     uint8_t             packetBytes[SIZEOF_PACKET_BYTES];
00141 
00142     static ResetPrepare_t handoverCallback;  /**< Application-specific handover callback. */
00143 };
00144 
00145 #endif /* #ifndef __BLE_DFU_SERVICE_H__*/
00146 #endif /* #ifdef TARGET_NRF51822 */