Android bluedroid模块间关系

一图解百惑

Android bluedroid模块间关系_第1张图片

整个bluedroid可以分为两大模块:BTIF,BTE

BTIF:提供bluedroid对外的接口

BTE:bluedroid的内部处理,又细分为BTA,BTU,BTM和HCI

BTA:bluedroid中各profile的逻辑实现和处理

BTU:承接BTA与HCI

BTM:蓝牙配对与链路管理

HCI:读取或写入数据到蓝牙hw


下面以实际例子来表现个模块间的协作

tv与蓝牙音箱建立连接

上层应用建立连接时候,会调用到btif_av.c中的connect函数

btif_av.c

static bt_status_t connect(bt_bdaddr_t *bd_addr)
 {
     BTIF_TRACE_EVENT1("%s", __FUNCTION__);
     CHECK_BTAV_INIT();          
  
     return btif_queue_connect(UUID_SERVCLASS_AUDIO_SOURCE, bd_addr, connect_int);                                                                                      
 }

经过内部逻辑处理后,会调用到bta_av_api.c中的BTA_AvOpen函数

void BTA_AvOpen(BD_ADDR bd_addr, tBTA_AV_HNDL handle, BOOLEAN use_rc, tBTA_SEC sec_mask)
170 {             
171     tBTA_AV_API_OPEN  *p_buf;
172 
173     if ((p_buf = (tBTA_AV_API_OPEN *) GKI_getbuf(sizeof(tBTA_AV_API_OPEN))) != NULL)
174     {         
175         p_buf->hdr.event = BTA_AV_API_OPEN_EVT;
176         p_buf->hdr.layer_specific   = handle;
177         bdcpy(p_buf->bd_addr, bd_addr);
178         p_buf->use_rc = use_rc;                                                                                                                                         
179         p_buf->sec_mask = sec_mask;
180         p_buf->switch_res = BTA_AV_RS_NONE;
181         bta_sys_sendmsg(p_buf);
182     }
183 } 
bta_sys_sendmsg最终会将消息发送btu_task.c中的btu_task线程处理

        for (;;)
227     {
228         event = GKI_wait (0xFFFF, 0);
229                                                                                                                                                                         
230         if (event & TASK_MBOX_0_EVT_MASK)
231         {
              ........
            }
            .
            .
            .
           if (event & TASK_MBOX_2_EVT_MASK)
549         {
550             while ((p_msg = (BT_HDR *) GKI_read_mbox(TASK_MBOX_2)) != NULL)
551             {
552                 bta_sys_event(p_msg);                                                                                                                                   
553             }
554         } 
通过bta_sys_event,消息再次转入bta内部处理,最终经过协议栈a2dp和l2cap和BTM的管理,将建立连接的请求通过bte_main.c的bte_main_hci_send发送给hci处理

void bte_main_hci_send (BT_HDR *p_msg, UINT16 event)                                                                                            
506 {                                                                                                                                               
507     UINT16 sub_event = event & BT_SUB_EVT_MASK;  /* local controller ID */                                                                      
508                                                                                                                                                 
509     p_msg->event = event;                                                                                                                       
510                                                                                                                                                 
511                                                                                                                                                 
512     if((sub_event == LOCAL_BR_EDR_CONTROLLER_ID) || \                                                                                           
513        (sub_event == LOCAL_BLE_CONTROLLER_ID))                                                                                                  
514     {                                                                                                                                                                   
515         if (bt_hc_if)                                                                                                                           
516             bt_hc_if->transmit_buf((TRANSAC)p_msg, \                                                                                            
517                                        (char *) (p_msg + 1), \                                                                                  
518                                         p_msg->len);                                                                                            
519         else                                                                                                                                    
520             GKI_freebuf(p_msg);                                                                                                                 
521     }                                                                                                                                           
522     else                                                                                                                                        
523     {                                                                                                                                           
524         APPL_TRACE_ERROR0("Invalid Controller ID. Discarding message.");                                                                        
525         GKI_freebuf(p_msg);                                                                                                                     
526     }                                                                                                                                           
527 }      


在hci中,数据被写入bt driver中

static int transmit_buf(TRANSAC transac, char *p_buf, int len)                                                                                                          
338 {       
339     utils_enqueue(&tx_q, (void *) transac);
340                                        
341     bthc_signal_event(HC_EVENT_TX);     
342         
343     return BT_HC_STATUS_SUCCESS;                                                                                                                
344 } 

bt_hc_worker_thread负责处理hci事件:
            if (events & HC_EVENT_TX)
529         {
530             /*
531              *  We will go through every packets in the tx queue.
532              *  Fine to clear tx_cmd_pkts_pending.
533              */
534             tx_cmd_pkts_pending = FALSE;
535             HC_BT_HDR * sending_msg_que[64];
536             int sending_msg_count = 0;
537             int sending_hci_cmd_pkts_count = 0;
538             utils_lock();
539             p_next_msg = tx_q.p_first;
540             while (p_next_msg && sending_msg_count <
541                             (int)sizeof(sending_msg_que)/sizeof(sending_msg_que[0]))
542             {
543                 if ((p_next_msg->event & MSG_EVT_MASK)==MSG_STACK_TO_HC_HCI_CMD)
544                 {
545                     /*
546                      *  if we have used up controller's outstanding HCI command
547                      *  credits (normally is 1), skip all HCI command packets in
548                      *  the queue.
549                      *  The pending command packets will be sent once controller
550                      *  gives back us credits through CommandCompleteEvent or
551                      *  CommandStatusEvent.
552                      */
553                     if ((tx_cmd_pkts_pending == TRUE) ||
554                         (sending_hci_cmd_pkts_count >= num_hci_cmd_pkts))
555                     {
556                         tx_cmd_pkts_pending = TRUE;
557                         p_next_msg = utils_getnext(p_next_msg);
558                         continue;
559                     }
560                     sending_hci_cmd_pkts_count++;
561                 }
562 
563                 p_msg = p_next_msg;
564                 p_next_msg = utils_getnext(p_msg);
565                 utils_remove_from_queue_unlocked(&tx_q, p_msg);
566                 sending_msg_que[sending_msg_count++] = p_msg;
567             }
                utils_unlock();
569             int i;
570             for(i = 0; i < sending_msg_count; i++)
571                 p_hci_if->send(sending_msg_que[i]);//将数据发送到bt driver中
572             if (tx_cmd_pkts_pending == TRUE)
573                 BTHCDBG("Used up Tx Cmd credits");
574 
575         }





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