ble_conn_params.cpp

00001 /* Copyright (c) 2012 Nordic Semiconductor. All Rights Reserved.
00002  *
00003  * The information contained herein is property of Nordic Semiconductor ASA.
00004  * Terms and conditions of usage are described in detail in NORDIC
00005  * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
00006  *
00007  * Licensees are granted free, non-transferable use of the information. NO
00008  * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
00009  * the file.
00010  *
00011  */
00012 
00013 #include "ble_conn_params.h "
00014 #include <stdlib.h>
00015 #include "nordic_common.h"
00016 #include "ble_hci.h"
00017 #include "ble_srv_common.h "
00018 #include "app_util.h "
00019 
00020 #ifdef USE_APP_TIMER
00021 #include "app_timer.h"
00022 #else
00023 #include "mbed.h"
00024 #endif
00025 
00026 static ble_conn_params_init_t m_conn_params_config;     /**< Configuration as specified by the application. */
00027 static ble_gap_conn_params_t  m_preferred_conn_params;  /**< Connection parameters preferred by the application. */
00028 static uint8_t                m_update_count;           /**< Number of Connection Parameter Update messages that has currently been sent. */
00029 static uint16_t               m_conn_handle;            /**< Current connection handle. */
00030 static ble_gap_conn_params_t  m_current_conn_params;    /**< Connection parameters received in the most recent Connect event. */
00031 #ifdef USE_APP_TIMER
00032 static app_timer_id_t         m_conn_params_timer_id;   /**< Connection parameters timer. */
00033 #else
00034 static Ticker                 m_conn_params_timer;
00035 #endif
00036 
00037 static bool m_change_param = false;
00038 
00039 static bool is_conn_params_ok(ble_gap_conn_params_t * p_conn_params)
00040 {
00041     // Check if interval is within the acceptable range.
00042     // NOTE: Using max_conn_interval in the received event data because this contains
00043     //       the client's connection interval.
00044     if (
00045         (p_conn_params->max_conn_interval >= m_preferred_conn_params.min_conn_interval)
00046         && 
00047         (p_conn_params->max_conn_interval <= m_preferred_conn_params.max_conn_interval)
00048        )
00049     {
00050         return true;
00051     }
00052     else
00053     {
00054         return false;
00055     }
00056 }
00057 
00058 
00059 #ifdef USE_APP_TIMER
00060 static void update_timeout_handler(void * p_context)
00061 {
00062     UNUSED_PARAMETER(p_context);
00063 
00064 #else /* #if !USE_APP_TIMER */
00065 static void update_timeout_handler(void)
00066 {
00067     m_conn_params_timer.detach(); /* this is supposed to be a single-shot timer callback */
00068 #endif /* #if !USE_APP_TIMER */
00069     if (m_conn_handle != BLE_CONN_HANDLE_INVALID)
00070     {
00071         // Check if we have reached the maximum number of attempts
00072         m_update_count++;
00073         if (m_update_count <= m_conn_params_config.max_conn_params_update_count)
00074         {
00075             uint32_t err_code;
00076 
00077             // Parameters are not ok, send connection parameters update request.
00078             err_code = sd_ble_gap_conn_param_update(m_conn_handle, &m_preferred_conn_params);
00079             if ((err_code != NRF_SUCCESS) && (m_conn_params_config.error_handler != NULL))
00080             {
00081                 m_conn_params_config.error_handler(err_code);
00082             }
00083         }
00084         else
00085         {
00086             m_update_count = 0;
00087 
00088             // Negotiation failed, disconnect automatically if this has been configured
00089             if (m_conn_params_config.disconnect_on_fail)
00090             {
00091                 uint32_t err_code;
00092 
00093                 err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
00094                 if ((err_code != NRF_SUCCESS) && (m_conn_params_config.error_handler != NULL))
00095                 {
00096                     m_conn_params_config.error_handler(err_code);
00097                 }
00098             }
00099 
00100             // Notify the application that the procedure has failed
00101             if (m_conn_params_config.evt_handler != NULL)
00102             {
00103                 ble_conn_params_evt_t evt;
00104 
00105                 evt.evt_type = BLE_CONN_PARAMS_EVT_FAILED;
00106                 m_conn_params_config.evt_handler(&evt);
00107             }
00108         }
00109     }
00110 }
00111 
00112 
00113 uint32_t ble_conn_params_init(const ble_conn_params_init_t * p_init)
00114 {
00115     uint32_t err_code;
00116 
00117     m_conn_params_config = *p_init;
00118     m_change_param = false;
00119     if (p_init->p_conn_params != NULL)
00120     {
00121         m_preferred_conn_params = *p_init->p_conn_params;
00122 
00123         // Set the connection params in stack
00124         err_code = sd_ble_gap_ppcp_set(&m_preferred_conn_params);
00125         if (err_code != NRF_SUCCESS)
00126         {
00127             return err_code;
00128         }
00129     }
00130     else
00131     {
00132         // Fetch the connection params from stack
00133         err_code = sd_ble_gap_ppcp_get(&m_preferred_conn_params);
00134         if (err_code != NRF_SUCCESS)
00135         {
00136             return err_code;
00137         }
00138     }
00139 
00140     m_conn_handle  = BLE_CONN_HANDLE_INVALID;
00141     m_update_count = 0;
00142 
00143 #ifdef USE_APP_TIMER
00144     return app_timer_create(&m_conn_params_timer_id,
00145                             APP_TIMER_MODE_SINGLE_SHOT,
00146                             update_timeout_handler);
00147 #else
00148     return NRF_SUCCESS;
00149 #endif
00150 }
00151 
00152 
00153 uint32_t ble_conn_params_stop(void)
00154 {
00155 #ifdef USE_APP_TIMER
00156     return app_timer_stop(m_conn_params_timer_id);
00157 #else /* #if !USE_APP_TIMER */
00158     m_conn_params_timer.detach();
00159     return NRF_SUCCESS;
00160 #endif /* #if !USE_APP_TIMER */
00161 }
00162 
00163 
00164 static void conn_params_negotiation(void)
00165 {
00166     // Start negotiation if the received connection parameters are not acceptable
00167     if (!is_conn_params_ok(&m_current_conn_params))
00168     {
00169 #ifdef USE_APP_TIMER
00170         uint32_t err_code;
00171 #endif
00172         uint32_t timeout_ticks;
00173 
00174         if (m_change_param)
00175         {
00176             // Notify the application that the procedure has failed
00177             if (m_conn_params_config.evt_handler != NULL)
00178             {
00179                 ble_conn_params_evt_t evt;
00180 
00181                 evt.evt_type = BLE_CONN_PARAMS_EVT_FAILED;
00182                 m_conn_params_config.evt_handler(&evt);
00183             }
00184         }
00185         else
00186         {
00187             if (m_update_count == 0)
00188             {
00189                 // First connection parameter update
00190                 timeout_ticks = m_conn_params_config.first_conn_params_update_delay;
00191             }
00192             else
00193             {
00194                 timeout_ticks = m_conn_params_config.next_conn_params_update_delay;
00195             }
00196 
00197 #ifdef USE_APP_TIMER
00198             err_code = app_timer_start(m_conn_params_timer_id, timeout_ticks, NULL);
00199             if ((err_code != NRF_SUCCESS) && (m_conn_params_config.error_handler != NULL))
00200             {
00201                 m_conn_params_config.error_handler(err_code);
00202             }
00203 #else
00204             m_conn_params_timer.attach(update_timeout_handler, timeout_ticks / 32768);
00205 #endif
00206         }
00207     }
00208     else
00209     {
00210         // Notify the application that the procedure has succeded
00211         if (m_conn_params_config.evt_handler != NULL)
00212         {
00213             ble_conn_params_evt_t evt;
00214 
00215             evt.evt_type = BLE_CONN_PARAMS_EVT_SUCCEEDED;
00216             m_conn_params_config.evt_handler(&evt);
00217         }
00218     }
00219     m_change_param = false;
00220 }
00221 
00222 
00223 static void on_connect(ble_evt_t * p_ble_evt)
00224 {
00225     // Save connection parameters
00226     m_conn_handle         = p_ble_evt->evt.gap_evt.conn_handle;
00227     m_current_conn_params = p_ble_evt->evt.gap_evt.params.connected.conn_params;
00228     m_update_count        = 0;  // Connection parameter negotiation should re-start every connection
00229 
00230     // Check if we shall handle negotiation on connect
00231     if (m_conn_params_config.start_on_notify_cccd_handle == BLE_GATT_HANDLE_INVALID)
00232     {
00233         conn_params_negotiation();
00234     }
00235 }
00236 
00237 
00238 static void on_disconnect(ble_evt_t * p_ble_evt)
00239 {
00240 #ifdef USE_APP_TIMER
00241     uint32_t err_code;
00242 #endif
00243 
00244     m_conn_handle = BLE_CONN_HANDLE_INVALID;
00245 
00246     // Stop timer if running
00247     m_update_count = 0; // Connection parameters updates should happen during every connection
00248 
00249 #ifdef USE_APP_TIMER
00250     err_code = app_timer_stop(m_conn_params_timer_id);
00251     if ((err_code != NRF_SUCCESS) && (m_conn_params_config.error_handler != NULL))
00252     {
00253         m_conn_params_config.error_handler(err_code);
00254     }
00255 #else
00256     m_conn_params_timer.detach();
00257 #endif
00258 }
00259 
00260 
00261 static void on_write(ble_evt_t * p_ble_evt)
00262 {
00263     ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
00264 
00265     // Check if this the correct CCCD
00266     if (
00267         (p_evt_write->handle == m_conn_params_config.start_on_notify_cccd_handle)
00268         &&
00269         (p_evt_write->len == 2)
00270        )
00271     {
00272         // Check if this is a 'start notification'
00273         if (ble_srv_is_notification_enabled(p_evt_write->data))
00274         {
00275             // Do connection parameter negotiation if necessary
00276             conn_params_negotiation();
00277         }
00278         else
00279         {
00280 #ifdef USE_APP_TIMER
00281             uint32_t err_code;
00282 
00283             // Stop timer if running
00284             err_code = app_timer_stop(m_conn_params_timer_id);
00285             if ((err_code != NRF_SUCCESS) && (m_conn_params_config.error_handler != NULL))
00286             {
00287                 m_conn_params_config.error_handler(err_code);
00288             }
00289 #else /* #if !USE_APP_TIMER */
00290             m_conn_params_timer.detach();
00291 #endif /* #if !USE_APP_TIMER */
00292         }
00293     }
00294 }
00295 
00296 
00297 static void on_conn_params_update(ble_evt_t * p_ble_evt)
00298 {
00299     // Copy the parameters
00300     m_current_conn_params = p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params;
00301 
00302     conn_params_negotiation();
00303 }
00304 
00305 
00306 void ble_conn_params_on_ble_evt(ble_evt_t * p_ble_evt)
00307 {
00308     switch (p_ble_evt->header.evt_id)
00309     {
00310         case BLE_GAP_EVT_CONNECTED:
00311             on_connect(p_ble_evt);
00312             break;
00313 
00314         case BLE_GAP_EVT_DISCONNECTED:
00315             on_disconnect(p_ble_evt);
00316             break;
00317 
00318         case BLE_GATTS_EVT_WRITE:
00319             on_write(p_ble_evt);
00320             break;
00321 
00322         case BLE_GAP_EVT_CONN_PARAM_UPDATE:
00323             on_conn_params_update(p_ble_evt);
00324             break;
00325 
00326         default:
00327             // No implementation needed.
00328             break;
00329     }
00330 }
00331 
00332 uint32_t ble_conn_params_change_conn_params(ble_gap_conn_params_t *new_params)
00333 {
00334     uint32_t err_code;
00335 
00336     m_preferred_conn_params = *new_params;
00337     // Set the connection params in stack
00338     err_code = sd_ble_gap_ppcp_set(&m_preferred_conn_params);
00339     if (err_code == NRF_SUCCESS)
00340     {
00341         if (!is_conn_params_ok(&m_current_conn_params))
00342         {
00343             m_change_param = true;
00344             err_code = sd_ble_gap_conn_param_update(m_conn_handle, &m_preferred_conn_params);
00345             m_update_count = 1;
00346         }
00347         else
00348         {
00349             // Notify the application that the procedure has succeded
00350             if (m_conn_params_config.evt_handler != NULL)
00351             {
00352                 ble_conn_params_evt_t evt;
00353 
00354                 evt.evt_type = BLE_CONN_PARAMS_EVT_SUCCEEDED;
00355                 m_conn_params_config.evt_handler(&evt);
00356             }
00357             err_code = NRF_SUCCESS;
00358         }
00359     }
00360     return err_code;
00361 }