Diff: nRF51822/btle/custom/custom_helper.cpp

Revision:

1:48f6e08a3ac2

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nRF51822/btle/custom/custom_helper.cpp	Wed Aug 20 13:24:20 2014 +0000
@@ -0,0 +1,247 @@
+/* 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.
+ */
+
+#include "custom_helper.h"
+
+/*
+ * The current version of the soft-device doesn't handle duplicate 128-bit UUIDs
+ * very  well. It is therefore necessary to filter away duplicates before
+ * passing long UUIDs to sd_ble_uuid_vs_add(). The following types and data
+ * structures involved in maintaining a local cache of 128-bit UUIDs.
+ */
+typedef struct {
+    LongUUID_t uuid;
+    uint8_t    type;
+} converted_uuid_table_entry_t;
+static const unsigned UUID_TABLE_MAX_ENTRIES = 8; /* This is the maximum number
+                                    * of 128-bit UUIDs with distinct bases that
+                                    * we expect to be in use; increase this
+                                    * limit if needed. */
+static unsigned uuidTableEntries = 0; /* current usage of the table */
+converted_uuid_table_entry_t convertedUUIDTable[UUID_TABLE_MAX_ENTRIES];
+
+/**
+ * lookup the cache of previously converted 128-bit UUIDs to find a type value.
+ * @param  uuid          long UUID
+ * @param  recoveredType the type field of the 3-byte nRF's uuid.
+ * @return               true if a match is found.
+ */
+static bool
+lookupConvertedUUIDTable(const LongUUID_t uuid, uint8_t *recoveredType)
+{
+    unsigned i;
+    for (i = 0; i < uuidTableEntries; i++) {
+        if (memcmp(convertedUUIDTable[i].uuid,
+                   uuid,
+                   LENGTH_OF_LONG_UUID) == 0) {
+            *recoveredType = convertedUUIDTable[i].type;
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static void
+addToConvertedUUIDTable(const LongUUID_t uuid, uint8_t type)
+{
+    if (uuidTableEntries == UUID_TABLE_MAX_ENTRIES) {
+        return; /* recovery needed; or at least the user should be
+                 * warned about this fact.*/
+    }
+
+    memcpy(convertedUUIDTable[uuidTableEntries].uuid, uuid,LENGTH_OF_LONG_UUID);
+    convertedUUIDTable[uuidTableEntries].type = type;
+    uuidTableEntries++;
+}
+
+/**
+ * The nRF transport has its own 3-byte representation of a UUID. If the user-
+ * specified UUID is 128-bits wide, then the UUID base needs to be added to the
+ * soft-device and converted to a 3-byte handle before being used further. This
+ * function is responsible for this translation of user-specified UUIDs into
+ * nRF's representation.
+ *
+ * @param[in]  uuid
+ *                 user-specified UUID
+ * @return nRF
+ *              3-byte UUID (containing a type and 16-bit UUID) representation
+ *              to be used with SVC calls.
+ */
+ble_uuid_t custom_convert_to_nordic_uuid(const UUID &uuid)
+{
+    ble_uuid_t nordicUUID = {
+        .uuid = uuid.getShortUUID(),
+        .type = BLE_UUID_TYPE_UNKNOWN /* to be set below */
+    };
+
+    if (uuid.shortOrLong() == UUID::UUID_TYPE_SHORT) {
+        nordicUUID.type = BLE_UUID_TYPE_BLE;
+    } else {
+        if (!lookupConvertedUUIDTable(uuid.getBaseUUID(), &nordicUUID.type)) {
+            nordicUUID.type = custom_add_uuid_base(uuid.getBaseUUID());
+            addToConvertedUUIDTable(uuid.getBaseUUID(), nordicUUID.type);
+        }
+    }
+
+    return nordicUUID;
+}
+
+/**************************************************************************/
+/*!
+    @brief      Adds the base UUID to the custom service. All UUIDs used
+                by this service are based on this 128-bit UUID.
+
+    @note       This UUID needs to be added to the SoftDevice stack before
+                adding the service's primary service via
+                'sd_ble_gatts_service_add'
+
+    @param[in]  p_uuid_base   A pointer to the 128-bit UUID array (8*16)
+
+    @returns    The UUID type.
+                A return value of 0 should be considered an error.
+
+    @retval     0x00    BLE_UUID_TYPE_UNKNOWN
+    @retval     0x01    BLE_UUID_TYPE_BLE
+    @retval     0x02    BLE_UUID_TYPE_VENDOR_BEGIN
+
+    @section EXAMPLE
+    @code
+
+    // Take note that bytes 2/3 are blank since these are used to identify
+    // the primary service and individual characteristics
+    #define CFG_CUSTOM_UUID_BASE  "\x6E\x40\x00\x00\xB5\xA3\xF3\x93\xE0\xA9\xE5\x0E\x24\xDC\xCA\x9E"
+
+    uint8_t uuid_type = custom_add_uuid_base(CFG_CUSTOM_UUID_BASE);
+    ASSERT(uuid_type > 0, ERROR_NOT_FOUND);
+
+    // We can now safely add the primary service and any characteristics
+    // for our custom service ...
+
+    @endcode
+*/
+/**************************************************************************/
+uint8_t custom_add_uuid_base(uint8_t const *const p_uuid_base)
+{
+    ble_uuid128_t base_uuid;
+    uint8_t       uuid_type = 0;
+
+    /* Reverse the bytes since ble_uuid128_t is LSB */
+    for (uint8_t i = 0; i<16; i++) {
+        base_uuid.uuid128[i] = p_uuid_base[15 - i];
+    }
+
+    ASSERT_INT( ERROR_NONE, sd_ble_uuid_vs_add( &base_uuid, &uuid_type ), 0);
+
+    return uuid_type;
+}
+
+/**************************************************************************/
+/*!
+
+*/
+/**************************************************************************/
+error_t custom_decode_uuid_base(uint8_t const *const p_uuid_base,
+                                ble_uuid_t          *p_uuid)
+{
+    LongUUID_t uuid_base_le;
+
+    /* Reverse the bytes since ble_uuid128_t is LSB */
+    for (uint8_t i = 0; i<16; i++) {
+        uuid_base_le[i] = p_uuid_base[15 - i];
+    }
+
+    ASSERT_STATUS( sd_ble_uuid_decode(16, uuid_base_le, p_uuid));
+
+    return ERROR_NONE;
+}
+
+/**************************************************************************/
+/*!
+    @brief      Adds a new characteristic to the custom service, assigning
+                properties, a UUID add-on value, etc.
+
+    @param[in]  service_handle
+    @param[in]  p_uuid            The 16-bit value to add to the base UUID
+                                  for this characteristic (normally >1
+                                  since 1 is typically used by the primary
+                                  service).
+    @param[in]  char_props        The characteristic properties, as
+                                  defined by ble_gatt_char_props_t
+    @param[in]  max_length        The maximum length of this characeristic
+    @param[in]  p_char_handle
+
+    @returns
+    @retval     ERROR_NONE        Everything executed normally
+*/
+/**************************************************************************/
+error_t custom_add_in_characteristic(uint16_t    service_handle,
+                                     ble_uuid_t *p_uuid,
+                                     uint8_t     properties,
+                                     uint8_t    *p_data,
+                                     uint16_t    min_length,
+                                     uint16_t    max_length,
+                                     ble_gatts_char_handles_t *p_char_handle)
+{
+    /* Characteristic metadata */
+    ble_gatts_attr_md_t   cccd_md;
+    ble_gatt_char_props_t char_props;
+
+    memcpy(&char_props, &properties, 1);
+
+    if (char_props.notify || char_props.indicate) {
+        /* Notification requires cccd */
+        memclr_( &cccd_md, sizeof(ble_gatts_attr_md_t));
+        cccd_md.vloc = BLE_GATTS_VLOC_STACK;
+        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.read_perm);
+        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&cccd_md.write_perm);
+    }
+
+    ble_gatts_char_md_t char_md = {0};
+
+    char_md.char_props = char_props;
+    char_md.p_cccd_md  =
+        (char_props.notify || char_props.indicate) ? &cccd_md : NULL;
+
+    /* Attribute declaration */
+    ble_gatts_attr_md_t attr_md = {0};
+
+    attr_md.vloc = BLE_GATTS_VLOC_STACK;
+    attr_md.vlen = (min_length == max_length) ? 0 : 1;
+
+    if (char_props.read || char_props.notify || char_props.indicate) {
+        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.read_perm);
+    }
+
+    if (char_props.write) {
+        BLE_GAP_CONN_SEC_MODE_SET_OPEN(&attr_md.write_perm);
+    }
+
+    ble_gatts_attr_t attr_char_value = {0};
+
+    attr_char_value.p_uuid    = p_uuid;
+    attr_char_value.p_attr_md = &attr_md;
+    attr_char_value.init_len  = min_length;
+    attr_char_value.max_len   = max_length;
+    attr_char_value.p_value   = p_data;
+
+    ASSERT_STATUS ( sd_ble_gatts_characteristic_add(service_handle,
+                                                    &char_md,
+                                                    &attr_char_value,
+                                                    p_char_handle));
+
+    return ERROR_NONE;
+}