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     LongUUIDBytes_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 of 128-bit UUIDs with distinct bases that
00030                                                    * we expect to be in use; increase this limit if needed. */
00031 static unsigned uuidTableEntries = 0; /* current usage of the table */
00032 converted_uuid_table_entry_t convertedUUIDTable[UUID_TABLE_MAX_ENTRIES];
00033 
00034 /**
00035  * lookup the cache of previously converted 128-bit UUIDs to find a type value.
00036  * @param  uuid          base 128-bit UUID
00037  * @param  recoveredType the type field of the 3-byte nRF's uuid.
00038  * @return               true if a match is found.
00039  */
00040 static bool
00041 lookupConvertedUUIDTable(const LongUUIDBytes_t uuid, uint8_t *recoveredType)
00042 {
00043     unsigned i;
00044     for (i = 0; i < uuidTableEntries; i++) {
00045         if (memcmp(convertedUUIDTable[i].uuid, uuid, LENGTH_OF_LONG_UUID) == 0) {
00046             *recoveredType = convertedUUIDTable[i].type;
00047             return true;
00048         }
00049     }
00050 
00051     return false;
00052 }
00053 
00054 static void
00055 addToConvertedUUIDTable(const LongUUIDBytes_t uuid, uint8_t type)
00056 {
00057     if (uuidTableEntries == UUID_TABLE_MAX_ENTRIES) {
00058         return; /* recovery needed; or at least the user should be warned about this fact.*/
00059     }
00060 
00061     memcpy(convertedUUIDTable[uuidTableEntries].uuid, uuid,LENGTH_OF_LONG_UUID);
00062     convertedUUIDTable[uuidTableEntries].type = type;
00063     uuidTableEntries++;
00064 }
00065 
00066 /**
00067  * The nRF transport has its own 3-byte representation of a UUID. If the user-
00068  * specified UUID is 128-bits wide, then the UUID base needs to be added to the
00069  * soft-device and converted to a 3-byte handle before being used further. This
00070  * function is responsible for this translation of user-specified UUIDs into
00071  * nRF's representation.
00072  *
00073  * @param[in]  uuid
00074  *                 user-specified UUID
00075  * @return nRF
00076  *              3-byte UUID (containing a type and 16-bit UUID) representation
00077  *              to be used with SVC calls.
00078  */
00079 ble_uuid_t custom_convert_to_nordic_uuid(const UUID &uuid)
00080 {
00081     ble_uuid_t nordicUUID = {
00082         .uuid = uuid.getShortUUID(),
00083         .type = BLE_UUID_TYPE_UNKNOWN /* to be set below */
00084     };
00085 
00086     if (uuid.shortOrLong() == UUID::UUID_TYPE_SHORT) {
00087         nordicUUID.type = BLE_UUID_TYPE_BLE;
00088     } else {
00089         if (!lookupConvertedUUIDTable(uuid.getBaseUUID(), &nordicUUID.type)) {
00090             nordicUUID.type = custom_add_uuid_base(uuid.getBaseUUID());
00091             addToConvertedUUIDTable(uuid.getBaseUUID(), nordicUUID.type);
00092         }
00093     }
00094 
00095     return nordicUUID;
00096 }
00097 
00098 /**************************************************************************/
00099 /*!
00100     @brief      Adds the base UUID to the custom service. All UUIDs used
00101                 by this service are based on this 128-bit UUID.
00102 
00103     @note       This UUID needs to be added to the SoftDevice stack before
00104                 adding the service's primary service via
00105                 'sd_ble_gatts_service_add'
00106 
00107     @param[in]  p_uuid_base   A pointer to the 128-bit UUID array (8*16)
00108 
00109     @returns    The UUID type.
00110                 A return value of 0 should be considered an error.
00111 
00112     @retval     0x00    BLE_UUID_TYPE_UNKNOWN
00113     @retval     0x01    BLE_UUID_TYPE_BLE
00114     @retval     0x02    BLE_UUID_TYPE_VENDOR_BEGIN
00115 
00116     @section EXAMPLE
00117     @code
00118 
00119     // Take note that bytes 2/3 are blank since these are used to identify
00120     // the primary service and individual characteristics
00121     #define CFG_CUSTOM_UUID_BASE  "\x6E\x40\x00\x00\xB5\xA3\xF3\x93\xE0\xA9\xE5\x0E\x24\xDC\xCA\x9E"
00122 
00123     uint8_t uuid_type = custom_add_uuid_base(CFG_CUSTOM_UUID_BASE);
00124     ASSERT(uuid_type > 0, ERROR_NOT_FOUND);
00125 
00126     // We can now safely add the primary service and any characteristics
00127     // for our custom service ...
00128 
00129     @endcode
00130 */
00131 /**************************************************************************/
00132 uint8_t custom_add_uuid_base(uint8_t const *const p_uuid_base)
00133 {
00134     ble_uuid128_t base_uuid;
00135     uint8_t       uuid_type = 0;
00136 
00137     /* Reverse the bytes since ble_uuid128_t is LSB */
00138     for (uint8_t i = 0; i<16; i++) {
00139         base_uuid.uuid128[i] = p_uuid_base[15 - i];
00140     }
00141 
00142     ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
00143 
00144     return uuid_type;
00145 }
00146 
00147 /**************************************************************************/
00148 /*!
00149 
00150 */
00151 /**************************************************************************/
00152 error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
00153                                 ble_uuid_t          *p_uuid)
00154 {
00155     LongUUIDBytes_t uuid_base_le;
00156 
00157     /* Reverse the bytes since ble_uuid128_t is LSB */
00158     for (uint8_t i = 0; i<16; i++) {
00159         uuid_base_le[i] = p_uuid_base[15 - i];
00160     }
00161 
00162     ASSERT_STATUS( sd_ble_uuid_decode(16, uuid_base_le, p_uuid));
00163 
00164     return ERROR_NONE;
00165 }
00166 
00167 /**************************************************************************/
00168 /*!
00169     @brief      Adds a new characteristic to the custom service, assigning
00170                 properties, a UUID add-on value, etc.
00171 
00172     @param[in]  service_handle
00173     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00174                                   for this characteristic (normally >1
00175                                   since 1 is typically used by the primary
00176                                   service).
00177     @param[in]  char_props        The characteristic properties, as
00178                                   defined by ble_gatt_char_props_t
00179     @param[in]  max_length        The maximum length of this characeristic
00180     @param[in]  p_char_handle
00181 
00182     @returns
00183     @retval     ERROR_NONE        Everything executed normally
00184 */
00185 /**************************************************************************/
00186 error_t custom_add_in_characteristic(uint16_t    service_handle,
00187                                      ble_uuid_t *p_uuid,
00188                                      uint8_t     properties,
00189                                      uint8_t    *p_data,
00190                                      uint16_t    min_length,
00191                                      uint16_t    max_length,
00192                                      ble_gatts_char_handles_t *p_char_handle)
00193 {
00194     /* Characteristic metadata */
00195     ble_gatts_attr_md_t   cccd_md;
00196     ble_gatt_char_props_t char_props;
00197 
00198     memcpy(&char_props, &properties, 1);
00199 
00200     if (char_props.notify || char_props.indicate) {
00201         /* Notification requires cccd */
00202         memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
00203         cccd_md.vloc = BLE_GATTS_VLOC_STACK;
00204         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
00205         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
00206     }
00207 
00208     ble_gatts_char_md_t char_md = {0};
00209 
00210     char_md.char_props = char_props;
00211     char_md.p_cccd_md  =
00212         (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
00213 
00214     /* Attribute declaration */
00215     ble_gatts_attr_md_t attr_md = {0};
00216 
00217     attr_md.vloc = BLE_GATTS_VLOC_STACK;
00218     attr_md.vlen = (min_length == max_length) ? 0 : 1;
00219 
00220     if (char_props.read || char_props.notify || char_props.indicate) {
00221         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
00222     }
00223 
00224     if (char_props.write) {
00225         BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
00226     }
00227 
00228     ble_gatts_attr_t attr_char_value = {0};
00229 
00230     attr_char_value.p_uuid    = p_uuid;
00231     attr_char_value.p_attr_md = &attr_md;
00232     attr_char_value.init_len  = min_length;
00233     attr_char_value.max_len   = max_length;
00234     attr_char_value.p_value   = p_data;
00235 
00236     ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
00237                                                     &char_md,
00238                                                     &attr_char_value,
00239                                                     p_char_handle));
00240 
00241     return ERROR_NONE;
00242 }
00243 
00244 
00245 
00246 /**************************************************************************/
00247 /*!
00248     @brief      Adds a new descriptor to the custom service, assigning
00249                 value, a UUID add-on value, etc.
00250 
00251     @param[in]  char_handle
00252     @param[in]  p_uuid            The 16-bit value to add to the base UUID
00253                                   for this descriptor (normally >1
00254                                   since 1 is typically used by the primary
00255                                   service).
00256     @param[in]  max_length        The maximum length of this descriptor
00257 
00258     @returns
00259     @retval     ERROR_NONE        Everything executed normally
00260 */
00261 /**************************************************************************/
00262 error_t custom_add_in_descriptor(uint16_t    char_handle,
00263                                              ble_uuid_t *p_uuid,
00264                                              uint8_t    *p_data,
00265                                              uint16_t    min_length,
00266                                              uint16_t    max_length,
00267                                              uint16_t   *p_desc_handle)
00268 {
00269     /* Descriptor metadata */
00270     ble_gatts_attr_md_t   desc_md = {0};
00271 
00272     desc_md.vloc = BLE_GATTS_VLOC_STACK;
00273     desc_md.vlen = (min_length == max_length) ? 0 : 1;
00274 
00275     /* Make it readable and writable */
00276     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.read_perm);
00277     BLE_GAP_CONN_SEC_MODE_SET_OPEN(&desc_md.write_perm);
00278 
00279     ble_gatts_attr_t attr_desc = {0};
00280 
00281     attr_desc.p_uuid    = p_uuid;
00282     attr_desc.p_attr_md = &desc_md;
00283     attr_desc.init_len  = min_length;
00284     attr_desc.max_len   = max_length;
00285     attr_desc.p_value   = p_data;
00286 
00287     ASSERT_STATUS ( sd_ble_gatts_descriptor_add(char_handle,
00288                                                 &attr_desc,
00289                                                 p_desc_handle));
00290 
00291     return ERROR_NONE;
00292 }