Enable characteristic 0x2A04 in GAP service

Add support to enable Peripheral Preferred Connection Parameters in GAP service and update it correctly

components/bt/host/bluedroid/Kconfig.in

@@ -121,6 +121,14 @@ config BT_GATTS_ENABLE
     help
         This option can be disabled when the app work only on gatt client mode
 
+config BT_GATTS_PPCP_CHAR_GAP
+    bool "Enable Peripheral Preferred Connection Parameters characteristic in GAP service"
+    depends on BT_GATTS_ENABLE
+    default n
+    help
+        This enables "Peripheral Preferred Connection Parameters" characteristic (UUID: 0x2A04) in GAP service that has
+        connection parameters like min/max connection interval, slave latency and supervision timeout multiplier
+
 choice BT_GATTS_SEND_SERVICE_CHANGE_MODE
     prompt "GATTS Service Change Mode"
     default BT_GATTS_SEND_SERVICE_CHANGE_AUTO

components/bt/host/bluedroid/bta/dm/bta_dm_act.c

@@ -4874,6 +4874,9 @@ void bta_dm_ble_set_conn_params (tBTA_DM_MSG *p_data)
                              p_data->ble_set_conn_params.conn_int_max,
                              p_data->ble_set_conn_params.slave_latency,
                              p_data->ble_set_conn_params.supervision_tout);
+
+    BTM_BleConfigConnParams(p_data->ble_set_conn_params.conn_int_min, p_data->ble_set_conn_params.conn_int_max,
+            p_data->ble_set_conn_params.slave_latency, p_data->ble_set_conn_params.supervision_tout);
 }
 
 /*******************************************************************************
@@ -4958,6 +4961,9 @@ void bta_dm_ble_update_conn_params (tBTA_DM_MSG *p_data)
                                   p_data->ble_update_conn_params.latency,
                                   p_data->ble_update_conn_params.timeout)) {
         APPL_TRACE_ERROR("Update connection parameters failed!");
+    } else {
+        BTM_BleConfigConnParams(p_data->ble_update_conn_params.min_int, p_data->ble_update_conn_params.max_int,
+            p_data->ble_update_conn_params.latency, p_data->ble_update_conn_params.timeout);
     }
 }
 /*******************************************************************************

components/bt/host/bluedroid/common/include/common/bluedroid_user_config.h

@@ -159,6 +159,12 @@
 #define UC_BT_BLE_HOST_QUEUE_CONGESTION_CHECK   FALSE
 #endif
 
+#ifdef CONFIG_BT_GATTS_PPCP_CHAR_GAP
+#define UC_CONFIG_BT_GATTS_PPCP_CHAR_GAP        CONFIG_BT_GATTS_PPCP_CHAR_GAP
+#else
+#define UC_CONFIG_BT_GATTS_PPCP_CHAR_GAP        FALSE
+#endif
+
 #ifdef CONFIG_BT_GATTS_SEND_SERVICE_CHANGE_MODE
 #define UC_BT_GATTS_SEND_SERVICE_CHANGE_MODE    CONFIG_BT_GATTS_SEND_SERVICE_CHANGE_MODE
 #else

components/bt/host/bluedroid/common/include/common/bt_target.h

@@ -383,6 +383,10 @@
 #define SCAN_QUEUE_CONGEST_CHECK  FALSE
 #endif
 
+#ifdef UC_CONFIG_BT_GATTS_PPCP_CHAR_GAP
+#define BTM_PERIPHERAL_ENABLED   UC_CONFIG_BT_GATTS_PPCP_CHAR_GAP
+#endif
+
 #ifdef UC_BT_GATTS_SEND_SERVICE_CHANGE_MODE
 #define GATTS_SEND_SERVICE_CHANGE_MODE UC_BT_GATTS_SEND_SERVICE_CHANGE_MODE
 #endif

components/bt/host/bluedroid/stack/btm/btm_ble_gap.c

@@ -910,6 +910,34 @@ void BTM_BleConfigLocalIcon(uint16_t icon)
     BTM_TRACE_ERROR("%s\n", __func__);
 #endif
 }
+
+/*******************************************************************************
+**
+** Function         BTM_BleConfigConnParams
+**
+** Description      This function is called to set the connection parameters
+**
+** Parameters       int_min:  minimum connection interval
+**                  int_max:  maximum connection interval
+**                  latency:  slave latency
+**                  timeout:  supervision timeout
+**
+*******************************************************************************/
+void BTM_BleConfigConnParams(uint16_t int_min, uint16_t int_max, uint16_t latency, uint16_t timeout)
+{
+#if (defined(GAP_INCLUDED) && GAP_INCLUDED == TRUE && GATTS_INCLUDED == TRUE)
+    tGAP_BLE_ATTR_VALUE p_value;
+
+    p_value.conn_param.int_min = int_min;
+    p_value.conn_param.int_max = int_max;
+    p_value.conn_param.latency = latency;
+    p_value.conn_param.sp_tout = timeout;
+    GAP_BleAttrDBUpdate(GATT_UUID_GAP_PREF_CONN_PARAM, &p_value);
+#else
+    BTM_TRACE_ERROR("%s\n", __func__);
+#endif
+}
+
 /*******************************************************************************
 **
 ** Function          BTM_BleMaxMultiAdvInstanceCount

components/bt/host/bluedroid/stack/include/stack/btm_ble_api.h

@@ -1718,6 +1718,20 @@ BOOLEAN BTM_BleConfigPrivacy(BOOLEAN enable, tBTM_SET_LOCAL_PRIVACY_CBACK *set_l
 *******************************************************************************/
 void BTM_BleConfigLocalIcon(uint16_t icon);
 
+/*******************************************************************************
+**
+** Function         BTM_BleConfigConnParams
+**
+** Description      This function is called to set the connection parameters
+**
+** Parameters       int_min:  minimum connection interval
+**                  int_max:  maximum connection interval
+**                  latency:  slave latency
+**                  timeout:  supervision timeout
+**
+*******************************************************************************/
+void BTM_BleConfigConnParams(uint16_t int_min, uint16_t int_max, uint16_t latency, uint16_t timeout);
+
 /*******************************************************************************
 **
 ** Function         BTM_BleLocalPrivacyEnabled