Diff: services/DFUService.h

Revision:

0:289fd2dae405

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/DFUService.h	Fri Dec 19 18:54:46 2014 +0000
@@ -0,0 +1,115 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __BLE_DFU_SERVICE_H__
+#define __BLE_DFU_SERVICE_H__
+
+#include "BLEDevice.h"
+#include "UUID.h"
+
+extern "C" void bootloader_start(void);
+
+extern const uint8_t  DFUServiceBaseUUID[];
+extern const uint16_t DFUServiceShortUUID;
+extern const uint16_t DFUServiceControlCharacteristicShortUUID;
+
+extern const uint8_t  DFUServiceUUID[];
+extern const uint8_t  DFUServiceControlCharacteristicUUID[];
+extern const uint8_t  DFUServicePacketCharacteristicUUID[];
+
+class DFUService {
+public:
+    /**
+     * Signature for the handover callback. The application may provide such a
+     * callback when setting up the DFU service, in which case it will be
+     * invoked before handing control over to the bootloader.
+     */
+    typedef void (*ResetPrepare_t)(void);
+
+public:
+    DFUService(BLEDevice &_ble, ResetPrepare_t _handoverCallback = NULL) :
+        ble(_ble),
+        controlBytes(),
+        packetBytes(),
+        controlPoint(DFUServiceControlCharacteristicUUID, controlBytes, SIZEOF_CONTROL_BYTES, SIZEOF_CONTROL_BYTES,
+                     GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
+        packet(DFUServicePacketCharacteristicUUID, packetBytes, SIZEOF_PACKET_BYTES, SIZEOF_PACKET_BYTES,
+               GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_WRITE_WITHOUT_RESPONSE) {
+        static bool serviceAdded = false; /* We should only ever need to add the DFU service once. */
+        if (serviceAdded) {
+            return;
+        }
+
+        /* Set an initial value for control bytes so that the application's DFUService can
+         * be distinguished from the real DFU service provided by the bootloader. */
+        controlBytes[0] = 0xFF;
+        controlBytes[1] = 0xFF;
+
+        GattCharacteristic *dfuChars[] = {&controlPoint, &packet};
+        GattService         dfuService(DFUServiceUUID, dfuChars, sizeof(dfuChars) / sizeof(GattCharacteristic *));
+
+        ble.addService(dfuService);
+        handoverCallback = _handoverCallback;
+        serviceAdded = true;
+
+        ble.onDataWritten(this, &DFUService::onDataWritten);
+    }
+
+    uint16_t getControlHandle(void) {
+        return controlPoint.getValueAttribute().getHandle();
+    }
+
+    /**
+     * This callback allows the DFU service to receive the initial trigger to
+     * handover control to the bootloader; but first the application is given a
+     * chance to clean up.
+     */
+    virtual void onDataWritten(const GattCharacteristicWriteCBParams *params) {
+        if (params->charHandle == controlPoint.getValueAttribute().getHandle()) {
+            /* At present, writing anything will do the trick--this needs to be improved. */
+            if (handoverCallback) {
+                handoverCallback();
+            }
+
+            bootloader_start();
+        }
+    }
+
+private:
+    static const unsigned SIZEOF_CONTROL_BYTES = 2;
+    static const unsigned SIZEOF_PACKET_BYTES  = 20;
+
+    static ResetPrepare_t handoverCallback;  /**< application specific handover callback. */
+
+private:
+    BLEDevice          &ble;
+    uint8_t             controlBytes[SIZEOF_CONTROL_BYTES];
+    uint8_t             packetBytes[SIZEOF_PACKET_BYTES];
+
+    /**< Writing to the control characteristic triggers the handover to dfu-
+      *  bootloader. At present, writing anything will do the trick--this needs
+      *  to be improved. */
+    GattCharacteristic  controlPoint;
+
+    /**< The packet characteristic in this service doesn't do anything meaningful, but
+      *  is only a placeholder to mimic the corresponding characteristic in the
+      *  actual DFU service implemented by the bootloader. Without this, some
+      *  FOTA clients might get confused as service definitions change after
+      *  handing control over to the bootloader. */
+    GattCharacteristic  packet;
+};
+
+#endif /* #ifndef __BLE_DFU_SERVICE_H__*/