custom_helper.cpp

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 #include "custom_helper.h"
00018 
00019 /*
00020  * The current version of the soft-device doesn't handle duplicate 128-bit UUIDs
00021  * very  well. It is therefore necessary to filter away duplicates before
00022  * passing long UUIDs to sd_ble_uuid_vs_add(). The following types and data
00023  * structures involved in maintaining a local cache of 128-bit UUIDs.
00024  */
00025 typedef struct {
00026     LongUUID_t uuid;
00027     uint8_t    type;
00028 } converted_uuid_table_entry_t;
00029 static const unsigned UUID_TABLE_MAX_ENTRIES = 8; /* This is the maximum number
00030                                     * of 128-bit UUIDs with distinct bases that
00031                                     * we expect to be in use; increase this
00032                                     * limit if needed. */
00033 static unsigned uuidTableEntries = 0; /* current usage of the table */
00034 converted_uuid_table_entry_t convertedUUIDTable[UUID_TABLE_MAX_ENTRIES];
00035 
00036 /**
00037  * lookup the cache of previously converted 128-bit UUIDs to find a type value.
00038  * @param  uuid          long UUID
00039  * @param  recoveredType the type field of the 3-byte nRF's uuid.
00040  * @return               true if a match is found.
00041  */
00042 static bool
00043 lookupConvertedUUIDTable(const LongUUID_t uuid, uint8_t *recoveredType)
00044 {
00045     unsigned i;
00046     for (i = 0; i < uuidTableEntries; i++) {
00047         if (memcmp(convertedUUIDTable[i].uuid,
00048                    uuid,
00049                    LENGTH_OF_LONG_UUID) == 0) {
00050             *recoveredType = convertedUUIDTable[i].type;
00051             return true;
00052         }
00053     }
00054 
00055     return false;
00056 }
00057 
00058 static void
00059 addToConvertedUUIDTable(const LongUUID_t uuid, uint8_t type)
00060 {
00061     if (uuidTableEntries == UUID_TABLE_MAX_ENTRIES) {
00062         return; /* recovery needed; or at least the user should be
00063                  * warned about this fact.*/
00064     }
00065 
00066     memcpy(convertedUUIDTable[uuidTableEntries].uuid, uuid,LENGTH_OF_LONG_UUID);
00067     convertedUUIDTable[uuidTableEntries].type = type;
00068     uuidTableEntries++;
00069 }
00070 
00071 /**
00072  * The nRF transport has its own 3-byte representation of a UUID. If the user-
00073  * specified UUID is 128-bits wide, then the UUID base needs to be added to the
00074  * soft-device and converted to a 3-byte handle before being used further. This
00075  * function is responsible for this translation of user-specified UUIDs into
00076  * nRF's representation.
00077  *
00078  * @param[in]  uuid
00079  *                 user-specified UUID
00080  * @return nRF
00081  *              3-byte UUID (containing a type and 16-bit UUID) representation
00082  *              to be used with SVC calls.
00083  */
00084 ble_uuid_t custom_convert_to_nordic_uuid(const UUID &uuid)
00085 {
00086     ble_uuid_t nordicUUID = {
00087         .uuid = uuid.getShortUUID(),
00088         .type = BLE_UUID_TYPE_UNKNOWN /* to be set below */
00089     };
00090 
00091     if (uuid.shortOrLong() == UUID::UUID_TYPE_SHORT) {
00092         nordicUUID.type = BLE_UUID_TYPE_BLE;
00093     } else {
00094         if (!lookupConvertedUUIDTable(uuid.getBaseUUID(), &nordicUUID.type)) {
00095             nordicUUID.type = custom_add_uuid_base(uuid.getBaseUUID());
00096             addToConvertedUUIDTable(uuid.getBaseUUID(), nordicUUID.type);
00097         }
00098     }
00099 
00100     return nordicUUID;
00101 }
00102 
00103 /**************************************************************************/
00104 /*!
00105     @brief      Adds the base UUID to the custom service. All UUIDs used
00106                 by this service are based on this 128-bit UUID.
00107 
00108     @note       This UUID needs to be added to the SoftDevice stack before
00109                 adding the service's primary service via
00110                 'sd_ble_gatts_service_add'
00111 
00112     @param[in]  p_uuid_base   A pointer to the 128-bit UUID array (8*16)
00113 
00114     @returns    The UUID type.
00115                 A return value of 0 should be considered an error.
00116 
00117     @retval     0x00    BLE_UUID_TYPE_UNKNOWN
00118     @retval     0x01    BLE_UUID_TYPE_BLE
00119     @retval     0x02    BLE_UUID_TYPE_VENDOR_BEGIN
00120 
00121     @section EXAMPLE
00122     @code
00123 
00124     // Take note that bytes 2/3 are blank since these are used to identify
00125     // the primary service and individual characteristics
00126     #define CFG_CUSTOM_UUID_BASE  "\x6E\x40\x00\x00\xB5\xA3\xF3\x93\xE0\xA9\xE5\x0E\x24\xDC\xCA\x9E"
00127 
00128     uint8_t uuid_type = custom_add_uuid_base(CFG_CUSTOM_UUID_BASE);
00129     ASSERT(uuid_type > 0, ERROR_NOT_FOUND);
00130 
00131     // We can now safely add the primary service and any characteristics
00132     // for our custom service ...
00133 
00134     @endcode
00135 */
00136 /**************************************************************************/
00137 uint8_t custom_add_uuid_base(uint8_t const *const p_uuid_base)
00138 {
00139     ble_uuid128_t base_uuid;
00140     uint8_t       uuid_type = 0;
00141 
00142     /* Reverse the bytes since ble_uuid128_t is LSB */
00143     for (uint8_t i = 0; i<16; i++) {
00144         base_uuid.uuid128[i] = p_uuid_base[15 - i];
00145     }
00146 
00147     ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
00148 
00149     return uuid_type;
00150 }
00151 
00152 /**************************************************************************/
00153 /*!
00154 
00155 */
00156 /**************************************************************************/
00157 error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
00158                                 ble_uuid_t          *p_uuid)
00159 {
00160     LongUUID_t uuid_base_le;
00161 
00162     /* Reverse the bytes since ble_uuid128_t is LSB */
00163     for (uint8_t i = 0; i<16; i++) {
00164         uuid_base_le[i] = p_uuid_base[15 - i];
00165     }
00166 
00167     ASSERT_STATUS( sd_ble_uuid_decode(16, uuid_base_le, p_uuid));
00168 
00169     return ERROR_NONE;
00170 }
00171 
00172 /**************************************************************************/
00173 /*!
00174     @brief      Adds a new characteristic to the custom service, assigning
00175                 properties, a UUID add-on value, etc.
00176 
00177     @param[in]  service_handle
00178     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00179                                   for this characteristic (normally >1
00180                                   since 1 is typically used by the primary
00181                                   service).
00182     @param[in]  char_props        The characteristic properties, as
00183                                   defined by ble_gatt_char_props_t
00184     @param[in]  max_length        The maximum length of this characeristic
00185     @param[in]  p_char_handle
00186 
00187     @returns
00188     @retval     ERROR_NONE        Everything executed normally
00189 */
00190 /**************************************************************************/
00191 error_t custom_add_in_characteristic(uint16_t    service_handle,
00192                                      ble_uuid_t *p_uuid,
00193                                      uint8_t     properties,
00194                                      uint8_t    *p_data,
00195                                      uint16_t    min_length,
00196                                      uint16_t    max_length,
00197                                      ble_gatts_char_handles_t *p_char_handle)
00198 {
00199     /* Characteristic metadata */
00200     ble_gatts_attr_md_t   cccd_md;
00201     ble_gatt_char_props_t char_props;
00202 
00203     memcpy(&char_props, &properties, 1);
00204 
00205     if (char_props.notify || char_props.indicate) {
00206         /* Notification requires cccd */
00207         memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
00208         cccd_md.vloc = BLE_GATTS_VLOC_STACK;
00209         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
00210         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
00211     }
00212 
00213     ble_gatts_char_md_t char_md = {0};
00214 
00215     char_md.char_props = char_props;
00216     char_md.p_cccd_md  =
00217         (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
00218 
00219     /* Attribute declaration */
00220     ble_gatts_attr_md_t attr_md = {0};
00221 
00222     attr_md.vloc = BLE_GATTS_VLOC_STACK;
00223     attr_md.vlen = (min_length == max_length) ? 0 : 1;
00224 
00225     if (char_props.read || char_props.notify || char_props.indicate) {
00226         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
00227     }
00228 
00229     if (char_props.write) {
00230         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
00231     }
00232 
00233     ble_gatts_attr_t attr_char_value = {0};
00234 
00235     attr_char_value.p_uuid    = p_uuid;
00236     attr_char_value.p_attr_md = &attr_md;
00237     attr_char_value.init_len  = min_length;
00238     attr_char_value.max_len   = max_length;
00239     attr_char_value.p_value   = p_data;
00240 
00241     ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
00242                                                     &char_md,
00243                                                     &attr_char_value,
00244                                                     p_char_handle));
00245 
00246     return ERROR_NONE;
00247 }