BlueDroid代码分析之初始化_bluedroid的库

作者：我家自动化 | 2024-07-13 15:56:15

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bluedroid的库

安卓蓝牙协议栈初始化

bluedroid协议栈初始化过程如下图所示：

Bluetooth.c是安卓蓝牙的硬件抽象，是BlueDroid的对外接口，供JNI直接调用。bluedroid编译出的库为bluetooth.default.so依赖于libbt-hci.so、libbt-utils.so、libbt-vendor.so等动态库。下面逐一分析安卓是怎么初始化协议栈的！本文是从协议栈bluedroid角度分析的，安卓的framework层次的初始化请参考

安卓蓝牙协议栈的初始化-java层次。

从上图可以看到，协议栈的初始化和enable过程创建了sock_poll_thread ,bt_hc_worker_thread,

btif_task,btu_task.sock_poll_thread跟蓝牙多媒体相关，bt_hc_worker_thread是串口的发送/接收数据进程，btif_task处理用户提交的命令，与HAL 和BTA交互进程,btu_task与L2CAP交互进程。下面我们着重分析下后面的两个进程：

在init的时候会创建btif_task进程，代码如下：

btif/src/btif_core.c


bt_status_t btif_init_bluetooth()
{
    UINT8 status;
    btif_config_init();//创建<span style="font-size: 18px;">sock_poll_thread，并获取配置文件</span>
    bte_main_boot_entry();//初始化GKI，加载厂商库和相关配置文件
 
    /* As part of the init, fetch the local BD ADDR */
    memset(&btif_local_bd_addr, 0, sizeof(bt_bdaddr_t));
    btif_fetch_local_bdaddr(&btif_local_bd_addr);  //从配置文件获取本地蓝牙的mac地址
 
    /* start btif task */
    status = GKI_create_task(btif_task, BTIF_TASK, BTIF_TASK_STR,
                (UINT16 *) ((UINT8 *)btif_task_stack + BTIF_TASK_STACK_SIZE),
                sizeof(btif_task_stack)); //创建btif_task进程
    if (status != GKI_SUCCESS)
        return BT_STATUS_FAIL;
 
    return BT_STATUS_SUCCESS;
}

btif_task代码路径：

btif/src/btif_core.c


static void btif_task(UINT32 params)
{
    UINT16   event;
    BT_HDR   *p_msg;
 
    BTIF_TRACE_DEBUG0("btif task starting");
 
    btif_associate_evt();//回调注册的thread_evt_cb，通知ASSOCIATE_JVM事件
 
    for(;;)
    {
        /* wait for specified events */
        event = GKI_wait(0xFFFF, 0);     //等待有效的事件，或者有消息发送到本进程时
                       //在GKI_send_msg最后也会发送event到本线程
        /*
         * Wait for the trigger to init chip and stack. This trigger will
         * be received by btu_task once the UART is opened and ready
         */
        if (event == BT_EVT_TRIGGER_STACK_INIT)
        {
            BTIF_TRACE_DEBUG0("btif_task: received trigger stack init event");
            #if (BLE_INCLUDED == TRUE)
            btif_dm_load_ble_local_keys();
            #endif
            BTA_EnableBluetooth(bte_dm_evt);
        }
 
        /*
         * Failed to initialize controller hardware, reset state and bring
         * down all threads
         */
        if (event == BT_EVT_HARDWARE_INIT_FAIL)
        {
            BTIF_TRACE_DEBUG0("btif_task: hardware init failed");
            bte_main_disable();
            btif_queue_release();
            GKI_task_self_cleanup(BTIF_TASK);
            bte_main_shutdown();
            btif_dut_mode = 0;
            btif_core_state = BTIF_CORE_STATE_DISABLED;
            HAL_CBACK(bt_hal_cbacks,adapter_state_changed_cb,BT_STATE_OFF);
            break;
        }
 
        if (event & EVENT_MASK(GKI_SHUTDOWN_EVT))
            break;
 
        if(event & TASK_MBOX_1_EVT_MASK)
        {
            while((p_msg = GKI_read_mbox(BTU_BTIF_MBOX)) != NULL) //从消息队列中读取消息
            {
                BTIF_TRACE_VERBOSE1("btif task fetched event %x", p_msg->event);
 
                switch (p_msg->event)
                {
                    case BT_EVT_CONTEXT_SWITCH_EVT:
                        btif_context_switched(p_msg); //执行消息内部注册的回调
                        break;
                    default:
                        BTIF_TRACE_ERROR1("unhandled btif event (%d)", p_msg->event & BT_EVT_MASK);
                        break;
                }
 
                GKI_freebuf(p_msg);
            }
        }
    }
 
    btif_disassociate_evt();
 
    BTIF_TRACE_DEBUG0("btif task exiting");
}

总结：btif_task实际上就是不停得从消息队列中取消息，并执行消息中注册的回调函数的过程

第二个核心进程时在bte_main_enable函数中创建的，代码如下：


void bte_main_enable()
{
    APPL_TRACE_DEBUG1("%s", __FUNCTION__);
 
    /* Initialize BTE control block */
    BTE_Init();//btu控制块的初始化
 
    lpm_enabled = FALSE;
 
    bte_hci_enable();//初始化厂商库并设置成power_on
 
    GKI_create_task((TASKPTR)btu_task, BTU_TASK, BTE_BTU_TASK_STR,
                    (UINT16 *) ((UINT8 *)bte_btu_stack + BTE_BTU_STACK_SIZE),
                    sizeof(bte_btu_stack));//创建第二大核心进程btu_task，主要是与L2CAP层的数据交互
 
    GKI_run(0);
}


BTU_API UINT32 btu_task (UINT32 param)
{
    UINT16           event;
    BT_HDR          *p_msg;
    UINT8            i;
    UINT16           mask;
    BOOLEAN          handled;
 
#if (defined(HCISU_H4_INCLUDED) && HCISU_H4_INCLUDED == TRUE)
    /* wait an event that HCISU is ready */
    BT_TRACE_0(TRACE_LAYER_BTU, TRACE_TYPE_API,
                "btu_task pending for preload complete event");
 
    for (;;)
    {
        event = GKI_wait (0xFFFF, 0); //
        if (event & EVENT_MASK(GKI_SHUTDOWN_EVT))
        {
            /* indicates BT ENABLE abort */
            BT_TRACE_0(TRACE_LAYER_BTU, TRACE_TYPE_WARNING,
                        "btu_task start abort!");
            return (0);
        }
        else if (event & BT_EVT_PRELOAD_CMPL)
        {
            break;
        }
        else
        {
            BT_TRACE_1(TRACE_LAYER_BTU, TRACE_TYPE_WARNING,
                "btu_task ignore evt %04x while pending for preload complete",
                event);
        }
    }
 
    BT_TRACE_0(TRACE_LAYER_BTU, TRACE_TYPE_API,
                "btu_task received preload complete event");
#endif
 
    /* Initialize the mandatory core stack control blocks
       (BTU, BTM, L2CAP, and SDP)
     */
    btu_init_core(); //初始化协议栈核心，btm l2cap 和sdp
 
    /* Initialize any optional stack components */
    BTE_InitStack(); //初始化协议栈profile 比如spp hid dun hfp RFCOMM等
 
#if (defined(BTU_BTA_INCLUDED) && BTU_BTA_INCLUDED == TRUE)
    bta_sys_init();      //注册bta系统回调
#endif
 
    /* Initialise platform trace levels at this point as BTE_InitStack() and bta_sys_init()
     * reset the control blocks and preset the trace level with XXX_INITIAL_TRACE_LEVEL
     */
#if ( BT_USE_TRACES==TRUE )
    BTE_InitTraceLevels();
#endif
 
    /* Send a startup evt message to BTIF_TASK to kickstart the init procedure */
    GKI_send_event(BTIF_TASK, BT_EVT_TRIGGER_STACK_INIT); 
	//发送BT_EVT_TRIGGER_STACK_INIT事件给btif_task
    raise_priority_a2dp(TASK_HIGH_BTU);
 
    /* Wait for, and process, events */
    for (;;)    //事件循环。。。
    {
        event = GKI_wait (0xFFFF, 0);
		//处理TASK_MBOX_0_EVT_MASK事件
        if (event & TASK_MBOX_0_EVT_MASK)
        {
            /* Process all messages in the queue */
            while ((p_msg = (BT_HDR *) GKI_read_mbox (BTU_HCI_RCV_MBOX)) != NULL)
            {
                /* Determine the input message type. */
                switch (p_msg->event & BT_EVT_MASK)
                {
                    case BT_EVT_TO_BTU_HCI_ACL:
                        /* All Acl Data goes to L2CAP */
                        l2c_rcv_acl_data (p_msg);
                        break;
 
                    case BT_EVT_TO_BTU_L2C_SEG_XMIT:
                        /* L2CAP segment transmit complete */
                        l2c_link_segments_xmitted (p_msg);
                        break;
 
                    case BT_EVT_TO_BTU_HCI_SCO:
#if BTM_SCO_INCLUDED == TRUE
                        btm_route_sco_data (p_msg);
                        break;
#endif
 
                    case BT_EVT_TO_BTU_HCI_EVT:
                        btu_hcif_process_event ((UINT8)(p_msg->event & BT_SUB_EVT_MASK), p_msg);
                        GKI_freebuf(p_msg);
 
#if (defined(HCILP_INCLUDED) && HCILP_INCLUDED == TRUE)
                        /* If host receives events which it doesn't response to, */
                        /* host should start idle timer to enter sleep mode.     */
                        btu_check_bt_sleep ();
#endif
                        break;
 
                    case BT_EVT_TO_BTU_HCI_CMD:
                        btu_hcif_send_cmd ((UINT8)(p_msg->event & BT_SUB_EVT_MASK), p_msg);
                        break;
 
#if (defined(OBX_INCLUDED) && OBX_INCLUDED == TRUE)
#if (defined(OBX_SERVER_INCLUDED) && OBX_SERVER_INCLUDED == TRUE)
                    case BT_EVT_TO_OBX_SR_MSG:
                        obx_sr_proc_evt((tOBX_PORT_EVT *)(p_msg + 1));
                        GKI_freebuf (p_msg);
                        break;
 
                    case BT_EVT_TO_OBX_SR_L2C_MSG:
                        obx_sr_proc_l2c_evt((tOBX_L2C_EVT_MSG *)(p_msg + 1));
                        GKI_freebuf (p_msg);
                        break;
#endif
 
#if (defined(OBX_CLIENT_INCLUDED) && OBX_CLIENT_INCLUDED == TRUE)
                    case BT_EVT_TO_OBX_CL_MSG:
                        obx_cl_proc_evt((tOBX_PORT_EVT *)(p_msg + 1));
                        GKI_freebuf (p_msg);
                        break;
 
                    case BT_EVT_TO_OBX_CL_L2C_MSG:
                        obx_cl_proc_l2c_evt((tOBX_L2C_EVT_MSG *)(p_msg + 1));
                        GKI_freebuf (p_msg);
                        break;
#endif
 
#if (defined(BIP_INCLUDED) && BIP_INCLUDED == TRUE)
                    case BT_EVT_TO_BIP_CMDS :
                        bip_proc_btu_event(p_msg);
                        GKI_freebuf (p_msg);
                        break;
#endif /* BIP */
#if (BPP_SND_INCLUDED == TRUE || BPP_INCLUDED == TRUE)
                    case BT_EVT_TO_BPP_PR_CMDS:
                        bpp_pr_proc_event(p_msg);
                        GKI_freebuf (p_msg);
                        break;
                    case BT_EVT_TO_BPP_SND_CMDS:
                        bpp_snd_proc_event(p_msg);
                        GKI_freebuf (p_msg);
                        break;
 
#endif /* BPP */
 
#endif /* OBX */
 
#if (defined(SAP_SERVER_INCLUDED) && SAP_SERVER_INCLUDED == TRUE)
                    case BT_EVT_TO_BTU_SAP :
                        sap_proc_btu_event(p_msg);
                        GKI_freebuf (p_msg);
                        break;
#endif /* SAP */
#if (defined(GAP_CONN_INCLUDED) && GAP_CONN_INCLUDED == TRUE && GAP_CONN_POST_EVT_INCLUDED == TRUE)
                    case BT_EVT_TO_GAP_MSG :
                        gap_proc_btu_event(p_msg);
                        GKI_freebuf (p_msg);
                        break;
#endif
                    case BT_EVT_TO_START_TIMER :
                        /* Start free running 1 second timer for list management */
                        GKI_start_timer (TIMER_0, GKI_SECS_TO_TICKS (1), TRUE);
                        GKI_freebuf (p_msg);
                        break;
 
                    case BT_EVT_TO_STOP_TIMER:
                        if (btu_cb.timer_queue.p_first == NULL)
                        {
                            GKI_stop_timer(TIMER_0);
                        }
                        GKI_freebuf (p_msg);
                        break;
 
#if defined(QUICK_TIMER_TICKS_PER_SEC) && (QUICK_TIMER_TICKS_PER_SEC > 0)
                    case BT_EVT_TO_START_QUICK_TIMER :
                        GKI_start_timer (TIMER_2, QUICK_TIMER_TICKS, TRUE);
                        GKI_freebuf (p_msg);
                        break;
#endif
 
                    default:
                        i = 0;
                        mask = (UINT16) (p_msg->event & BT_EVT_MASK);
                        handled = FALSE;
 
                        for (; !handled && i < BTU_MAX_REG_EVENT; i++)
                        {
                            if (btu_cb.event_reg[i].event_cb == NULL)
                                continue;
 
                            if (mask == btu_cb.event_reg[i].event_range)
                            {
                                if (btu_cb.event_reg[i].event_cb)
                                {
                                    btu_cb.event_reg[i].event_cb(p_msg);
                                    handled = TRUE;
                                }
                            }
                        }
 
                        if (handled == FALSE)
                            GKI_freebuf (p_msg);
 
                        break;
                }
            }
        }
 
		//处理TIMER_0_EVT_MASK事件
        if (event & TIMER_0_EVT_MASK)
        {
            TIMER_LIST_ENT  *p_tle;
 
            GKI_update_timer_list (&btu_cb.timer_queue, 1);
 
            while ((btu_cb.timer_queue.p_first) && (!btu_cb.timer_queue.p_first->ticks))
            {
                p_tle = btu_cb.timer_queue.p_first;
                GKI_remove_from_timer_list (&btu_cb.timer_queue, p_tle);
 
                switch (p_tle->event)
                {
                    case BTU_TTYPE_BTM_DEV_CTL:
                        btm_dev_timeout(p_tle);
                        break;
 
                    case BTU_TTYPE_BTM_ACL:
                        btm_acl_timeout(p_tle);
                        break;
 
                    case BTU_TTYPE_L2CAP_LINK:
                    case BTU_TTYPE_L2CAP_CHNL:
                    case BTU_TTYPE_L2CAP_HOLD:
                    case BTU_TTYPE_L2CAP_INFO:
                    case BTU_TTYPE_L2CAP_FCR_ACK:
 
                        l2c_process_timeout (p_tle);
                        break;
 
                    case BTU_TTYPE_SDP:
                        sdp_conn_timeout ((tCONN_CB *)p_tle->param);
                        break;
 
                    case BTU_TTYPE_BTM_RMT_NAME:
                        btm_inq_rmt_name_failed();
                        break;
 
#if (defined(RFCOMM_INCLUDED) && RFCOMM_INCLUDED == TRUE)
                    case BTU_TTYPE_RFCOMM_MFC:
                    case BTU_TTYPE_RFCOMM_PORT:
                        rfcomm_process_timeout (p_tle);
                        break;
 
#endif /* If defined(RFCOMM_INCLUDED) && RFCOMM_INCLUDED == TRUE */
 
#if ((defined(BNEP_INCLUDED) && BNEP_INCLUDED == TRUE))
                    case BTU_TTYPE_BNEP:
                        bnep_process_timeout(p_tle);
                        break;
#endif
 
 
#if (defined(AVDT_INCLUDED) && AVDT_INCLUDED == TRUE)
                    case BTU_TTYPE_AVDT_CCB_RET:
                    case BTU_TTYPE_AVDT_CCB_RSP:
                    case BTU_TTYPE_AVDT_CCB_IDLE:
                    case BTU_TTYPE_AVDT_SCB_TC:
                        avdt_process_timeout(p_tle);
                        break;
#endif
 
#if (defined(OBX_INCLUDED) && OBX_INCLUDED == TRUE)
#if (defined(OBX_CLIENT_INCLUDED) && OBX_CLIENT_INCLUDED == TRUE)
                    case BTU_TTYPE_OBX_CLIENT_TO:
                        obx_cl_timeout(p_tle);
                        break;
#endif
#if (defined(OBX_SERVER_INCLUDED) && OBX_SERVER_INCLUDED == TRUE)
                    case BTU_TTYPE_OBX_SERVER_TO:
                        obx_sr_timeout(p_tle);
                        break;
 
                    case BTU_TTYPE_OBX_SVR_SESS_TO:
                        obx_sr_sess_timeout(p_tle);
                        break;
#endif
#endif
 
#if (defined(SAP_SERVER_INCLUDED) && SAP_SERVER_INCLUDED == TRUE)
                    case BTU_TTYPE_SAP_TO:
                        sap_process_timeout(p_tle);
                        break;
#endif
 
                    case BTU_TTYPE_BTU_CMD_CMPL:
                        btu_hcif_cmd_timeout((UINT8)(p_tle->event - BTU_TTYPE_BTU_CMD_CMPL));
                        break;
 
#if (defined(HID_HOST_INCLUDED) && HID_HOST_INCLUDED == TRUE)
                    case BTU_TTYPE_HID_HOST_REPAGE_TO :
                        hidh_proc_repage_timeout(p_tle);
                        break;
#endif
 
#if (defined(BLE_INCLUDED) && BLE_INCLUDED == TRUE)
                    case BTU_TTYPE_BLE_INQUIRY:
                    case BTU_TTYPE_BLE_GAP_LIM_DISC:
                    case BTU_TTYPE_BLE_RANDOM_ADDR:
                        btm_ble_timeout(p_tle);
                        break;
 
                    case BTU_TTYPE_ATT_WAIT_FOR_RSP:
                        gatt_rsp_timeout(p_tle);
                        break;
 
                    case BTU_TTYPE_ATT_WAIT_FOR_IND_ACK:
                        gatt_ind_ack_timeout(p_tle);
                        break;
#if (defined(SMP_INCLUDED) && SMP_INCLUDED == TRUE)
                    case BTU_TTYPE_SMP_PAIRING_CMD:
                        smp_rsp_timeout(p_tle);
                        break;
#endif
 
#endif
 
#if (MCA_INCLUDED == TRUE)
                    case BTU_TTYPE_MCA_CCB_RSP:
                        mca_process_timeout(p_tle);
                        break;
#endif
                    case BTU_TTYPE_USER_FUNC:
                        {
                            tUSER_TIMEOUT_FUNC  *p_uf = (tUSER_TIMEOUT_FUNC *)p_tle->param;
                            (*p_uf)(p_tle);
                        }
                        break;
 
                    default:
                        i = 0;
                        handled = FALSE;
 
                        for (; !handled && i < BTU_MAX_REG_TIMER; i++)
                        {
                            if (btu_cb.timer_reg[i].timer_cb == NULL)
                                continue;
                            if (btu_cb.timer_reg[i].p_tle == p_tle)
                            {
                                btu_cb.timer_reg[i].timer_cb(p_tle);
                                handled = TRUE;
                            }
                        }
                        break;
                }
            }
 
            /* if timer list is empty stop periodic GKI timer */
            if (btu_cb.timer_queue.p_first == NULL)
            {
                GKI_stop_timer(TIMER_0);
            }
        }
 
#if defined(QUICK_TIMER_TICKS_PER_SEC) && (QUICK_TIMER_TICKS_PER_SEC > 0)
		//处理TIMER_2_EVT_MASK事件
        if (event & TIMER_2_EVT_MASK)
        {
            btu_process_quick_timer_evt();
        }
#endif
 
 
#if (RPC_INCLUDED == TRUE)
        /* if RPC message queue event */
		//处理RPCGEN_MSG_EVT事件
        if (event & RPCGEN_MSG_EVT)
        {
            if ((p_msg = (BT_HDR *) GKI_read_mbox(RPCGEN_MSG_MBOX)) != NULL)
                RPCT_RpcgenMsg(p_msg);  /* handle RPC message queue */
        }
#endif
 
#if (defined(BTU_BTA_INCLUDED) && BTU_BTA_INCLUDED == TRUE)
		//处理TASK_MBOX_2_EVT_MASK事件
        if (event & TASK_MBOX_2_EVT_MASK)
        {
            while ((p_msg = (BT_HDR *) GKI_read_mbox(TASK_MBOX_2)) != NULL)
            {
                bta_sys_event(p_msg);
            }
        }
		//处理TIMER_1_EVT_MASK事件
        if (event & TIMER_1_EVT_MASK)
        {
            bta_sys_timer_update();
        }
#endif
 
        if (event & EVENT_MASK(APPL_EVT_7))
            break;
    }
 
    return(0);
}
总结：btu_task等待并处理如下事件
TASK_MBOX_0_EVT_MASK
TIMER_0_EVT_MASK
TIMER_2_EVT_MASK
RPCGEN_MSG_EVT
TASK_MBOX_2_EVT_MASK
TIMER_1_EVT_MASK
处理事件的过程实际上就是调用回调函数的过程，具体过程请参考回调函数的注册！

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