蓝牙inquiry流程之Inquiry Complete处理

2022-01-31 13:03:37

inquiry流程一般持续有12s多，当inquiry完成的时候，设备端会上报一个Event: Inquiry Complete 上来，那协议栈是如何把这个事件上传到应用层的呢？本篇文章来分析一下其具体的流程。

void btu_hcif_process_event (UNUSED_ATTR UINT8 controller_id, BT_HDR *p_msg)

{

    UINT8   *p = (UINT8 *)(p_msg + ) + p_msg->offset;

    UINT8   hci_evt_code, hci_evt_len;

    STREAM_TO_UINT8  (hci_evt_code, p);

    STREAM_TO_UINT8  (hci_evt_len, p);

    switch (hci_evt_code)

    {

        case HCI_INQUIRY_COMP_EVT:

            btu_hcif_inquiry_comp_evt (p);

            break;

...

看btu_hcif_inquiry_comp_evt 的实现：

static void btu_hcif_inquiry_comp_evt (UINT8 *p)

{

    UINT8   status;

    STREAM_TO_UINT8    (status, p);

    /* Tell inquiry processing that we are done */

    btm_process_inq_complete(status, BTM_BR_INQUIRY_MASK);

}

继续看btm_process_inq_complete 的实现：

其中：

#define BTM_BR_INQUIRY_MASK         (BTM_GENERAL_INQUIRY | BTM_LIMITED_INQUIRY)

btm_process_inq_complete 其实现在btm_inq.c里面：

void btm_process_inq_complete (UINT8 status, UINT8 mode)

{

    tBTM_CMPL_CB        *p_inq_cb = btm_cb.btm_inq_vars.p_inq_cmpl_cb;//保存回调函数指针

    tBTM_INQUIRY_VAR_ST *p_inq = &btm_cb.btm_inq_vars;

...

#if (!defined(BTA_HOST_INTERLEAVE_SEARCH) || BTA_HOST_INTERLEAVE_SEARCH == FALSE)

     p_inq->inqparms.mode &= ~(mode);

#endif

    btm_acl_update_busy_level (BTM_BLI_INQ_DONE_EVT);//向上传递

    /* Ignore any stray or late complete messages if the inquiry is not active */

    if (p_inq->inq_active)

    {

        p_inq->inq_cmpl_info.status = (tBTM_STATUS)((status == HCI_SUCCESS) ? BTM_SUCCESS : BTM_ERR_PROCESSING);

        /* Notify caller that the inquiry has completed; (periodic inquiries do not send completion events */

        if (!(p_inq->inq_active & BTM_PERIODIC_INQUIRY_ACTIVE) && p_inq->inqparms.mode == )//mode前面已经置0

        {

#if BLE_INCLUDED == TRUE

            btm_clear_all_pending_le_entry();//清除还没有活动scan response的设备消息

#endif

            p_inq->state = BTM_INQ_INACTIVE_STATE;//设置inquiry的状态

            /* Increment so the start of a next inquiry has a new count */

            p_inq->inq_counter++；//增加搜索的计数

            btm_clr_inq_result_flt();

            if((p_inq->inq_cmpl_info.status == BTM_SUCCESS) &&

                controller_get_interface()->supports_rssi_with_inquiry_results())

            {

                btm_sort_inq_result();//根据rssi排序

            }

            /* Clear the results callback if set */

            p_inq->p_inq_results_cb = (tBTM_INQ_RESULTS_CB *) NULL;

            p_inq->inq_active = BTM_INQUIRY_INACTIVE;//设置0

            p_inq->p_inq_cmpl_cb = (tBTM_CMPL_CB *) NULL;

            if (p_inq_cb)//执行回调函数，在bta_dm_search_start 进行注册bta_dm_inq_cmpl_cb

                (p_inq_cb)((tBTM_INQUIRY_CMPL *) &p_inq->inq_cmpl_info);

        }

    }

    if(p_inq->inqparms.mode ==  && p_inq->scan_type == INQ_GENERAL)//this inquiry is complete

    {

        p_inq->scan_type = INQ_NONE;//scan_type置0

#if (defined BLE_INCLUDED && BLE_INCLUDED == TRUE)

        /* check if the LE observe is pending */

        if(p_inq->p_inq_ble_results_cb != NULL)//==NULL

        {

            BTM_TRACE_DEBUG("BTM Inq Compl: resuming a pending LE scan");

            BTM_BleObserve(,, p_inq->p_inq_ble_results_cb, p_inq->p_inq_ble_cmpl_cb);

        }

#endif

    }

}

这里主要分三部分：

btm_acl_update_busy_level (BTM_BLI_INQ_DONE_EVT); 向上层汇报状态
清各种状态标志位
(p_inq_cb)((tBTM_INQUIRY_CMPL *) &p_inq->inq_cmpl_info);

我们主要看一下第一部分和第三部分：

1.btm_acl_update_busy_level

其实现btm_acl.c：

void btm_acl_update_busy_level (tBTM_BLI_EVENT event)

{

    tBTM_BL_UPDATE_DATA  evt;

    UINT8 busy_level;

    BTM_TRACE_DEBUG ("btm_acl_update_busy_level");

    BOOLEAN old_inquiry_state = btm_cb.is_inquiry;

    switch (event)

    {

...

        case BTM_BLI_INQ_DONE_EVT:

            BTM_TRACE_DEBUG ("BTM_BLI_INQ_DONE_EVT");

            btm_cb.is_inquiry = FALSE;

            evt.busy_level_flags = BTM_BL_INQUIRY_COMPLETE;

            break;

    }

...

    if ((busy_level != btm_cb.busy_level) ||(old_inquiry_state != btm_cb.is_inquiry))

    {

        evt.event         = BTM_BL_UPDATE_EVT;

        evt.busy_level    = busy_level;

        btm_cb.busy_level = busy_level;

        if (btm_cb.p_bl_changed_cb && (btm_cb.bl_evt_mask & BTM_BL_UPDATE_MASK))

        {

            (*btm_cb.p_bl_changed_cb)((tBTM_BL_EVENT_DATA *)&evt);

        }

    }

}

可以看出，主要做的事情是组建一个evt：

evt.event = BTM_BL_UPDATE_EVT;
evt.busy_level = busy_level;

evt.busy_level_flags = BTM_BL_INQUIRY_COMPLETE;

然后调用 (*btm_cb.p_bl_changed_cb)((tBTM_BL_EVENT_DATA *)&evt);

看看这个回调函数是在哪里注册的呢？

在btm_acl.c有个注册函数：

tBTM_STATUS BTM_RegBusyLevelNotif (tBTM_BL_CHANGE_CB *p_cb, UINT8 *p_level,

                                   tBTM_BL_EVENT_MASK evt_mask)

{

...
    btm_cb.bl_evt_mask = evt_mask;

...

    btm_cb.p_bl_changed_cb = p_cb;//保存回调

    return(BTM_SUCCESS);

}

发现该函数是在bta_dm_sys_hw_cback里面注册的：

BTM_RegBusyLevelNotif (bta_dm_bl_change_cback, NULL, BTM_BL_UPDATE_MASK|BTM_BL_ROLE_CHG_MASK);

我们发现这个回调函数就是bta_dm_bl_change_cback ，其实现在bta_dm_act.c中：

根据上面的分析，我们知道这次传入的event = BTM_BL_UPDATE_EVT;

static void bta_dm_bl_change_cback (tBTM_BL_EVENT_DATA *p_data)

{

    tBTA_DM_ACL_CHANGE * p_msg;

    if ((p_msg = (tBTA_DM_ACL_CHANGE *) GKI_getbuf(sizeof(tBTA_DM_ACL_CHANGE))) != NULL)

    {

        p_msg->event = p_data->event;.//继承上面event

        p_msg->is_new = FALSE;//is_new = false

        switch(p_msg->event)

        {

...

        case BTM_BL_UPDATE_EVT:

            p_msg->busy_level = p_data->update.busy_level;

            p_msg->busy_level_flags = p_data->update.busy_level_flags;

            break;

...

      }

        p_msg->hdr.event = BTA_DM_ACL_CHANGE_EVT;

        bta_sys_sendmsg(p_msg);

    }

}

观其实现，还是组建了一个 tBTA_DM_ACL_CHANGE 这样的事件，然后发送到btu 线程：

p_msg->hdr.event = BTA_DM_ACL_CHANGE_EVT;

p_msg->event = p_data->event = BTM_BL_UPDATE_EVT;
p_msg->is_new = FALSE;

这边追踪一下代码，处理这个BTA_DM_ACL_CHANGE_EVT的函数是：

/*******************************************************************************

**

** Function         bta_dm_acl_change

**

** Description      Process BTA_DM_ACL_CHANGE_EVT

**

**

** Returns          void

**

*******************************************************************************/

void bta_dm_acl_change(tBTA_DM_MSG *p_data)

{

    UINT8 i;

    UINT8 *p;

    tBTA_DM_SEC conn;

    BOOLEAN is_new = p_data->acl_change.is_new;

    BD_ADDR_PTR     p_bda = p_data->acl_change.bd_addr;

    BOOLEAN         need_policy_change = FALSE;

    BOOLEAN         issue_unpair_cb = FALSE;

    tBTA_DM_PEER_DEVICE *p_dev;

    memset(&conn, , sizeof(tBTA_DM_SEC));

    switch(p_data->acl_change.event)

    {

    case BTM_BL_UPDATE_EVT:     /* busy level update */

        if( bta_dm_cb.p_sec_cback )

        {

            conn.busy_level.level = p_data->acl_change.busy_level;

            conn.busy_level.level_flags = p_data->acl_change.busy_level_flags;

            bta_dm_cb.p_sec_cback(BTA_DM_BUSY_LEVEL_EVT, &conn);//回调到上层

        }

        return;

...

这边的核心代码还是组建事件往上层回调，:

conn.busy_level.level = p_data->acl_change.busy_level;
conn.busy_level.level_flags = p_data->acl_change.busy_level_flags = BTM_BL_INQUIRY_COMPLETE;
bta_dm_cb.p_sec_cback(BTA_DM_BUSY_LEVEL_EVT, &conn);

那我们现在看看bta_dm_cb.p_sec_cback 这个回调函数是在哪里注册的：

void bta_dm_enable(tBTA_DM_MSG *p_data){

...

    /* first, register our callback to SYS HW manager */

    bta_sys_hw_register( BTA_SYS_HW_BLUETOOTH, bta_dm_sys_hw_cback );

    bta_dm_cb.p_sec_cback = p_data->enable.p_sec_cback;//注册回调

...

}

发现是在bta_dm_enable 里面注册的，也就是在tBTA_STATUS BTA_EnableBluetooth(tBTA_DM_SEC_CBACK *p_cback) 传入的回调函数：

void btif_init_ok(UNUSED_ATTR uint16_t event, UNUSED_ATTR char *p_param) {

  BTIF_TRACE_DEBUG("btif_task: received trigger stack init event");

#if (BLE_INCLUDED == TRUE)

  btif_dm_load_ble_local_keys();

#endif

  BTA_EnableBluetooth(bte_dm_evt);//这里注册

}

那我们知道上面回调的内容如下：

conn.busy_level.level = p_data->acl_change.busy_level;
conn.busy_level.level_flags = p_data->acl_change.busy_level_flags = BTM_BL_INQUIRY_COMPLETE;
bte_dm_evt(BTA_DM_BUSY_LEVEL_EVT, &conn);

，下面继续分析bte_dm_evt：

void bte_dm_evt(tBTA_DM_SEC_EVT event, tBTA_DM_SEC *p_data)

{

    /* switch context to btif task context (copy full union size for convenience) */

    bt_status_t status = btif_transfer_context(btif_dm_upstreams_evt, (uint16_t)event,

                                (void*)p_data, sizeof(tBTA_DM_SEC), btif_dm_data_copy);

    /* catch any failed context transfers */

    ASSERTC(status == BT_STATUS_SUCCESS, "context transfer failed", status);

}

发现该函数就是一个中转，他把事件交与bt_jni_workqueue_thread 线程中的btif_dm_upstreams_evt 函数去执行了。event从btu task 转换到了bt_jni_workqueue_thread ，我们也能感受到，事件正在一层一层往上面走，

看看btif_dm_upstreams_evt 的实现，这里面肯定也是会去处理各种不同的event：我们这种case 要处理的event = BTA_DM_BUSY_LEVEL_EVT,

/*******************************************************************************

**

** Function         btif_dm_upstreams_cback

**

** Description      Executes UPSTREAMS events in btif context

**

** Returns          void

**

*******************************************************************************/

static void btif_dm_upstreams_evt(UINT16 event, char* p_param)

{

    tBTA_DM_SEC *p_data = (tBTA_DM_SEC*)p_param;

    tBTA_SERVICE_MASK service_mask;

    uint32_t i;

    bt_bdaddr_t bd_addr;

    switch (event)

    {

     case BTA_DM_BUSY_LEVEL_EVT:

        {

            if (p_data->busy_level.level_flags & BTM_BL_INQUIRY_PAGING_MASK)

            {

                if (p_data->busy_level.level_flags == BTM_BL_INQUIRY_STARTED)

                {

                       HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb,

                                                BT_DISCOVERY_STARTED);

                       btif_dm_inquiry_in_progress = TRUE;

                }

                else if (p_data->busy_level.level_flags == BTM_BL_INQUIRY_CANCELLED)

                {

                       HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb,

                                                BT_DISCOVERY_STOPPED);

                       btif_dm_inquiry_in_progress = FALSE;

                }

                else if (p_data->busy_level.level_flags == BTM_BL_INQUIRY_COMPLETE)

                {

                       btif_dm_inquiry_in_progress = FALSE;//设置了这个值

                }

            }

        }

从上面的代码分析，这里做的最重要的一件事就是：

btif_dm_inquiry_in_progress = FALSE;
第一部分的分析到此结束，下面开始看inquiry结束之后的回调函数：

3.(p_inq_cb)((tBTM_INQUIRY_CMPL *) &p_inq->inq_cmpl_info) = bta_dm_inq_cmpl_cb

这个回调函数的注册是在进行搜索的时候：

void bta_dm_search_start (tBTA_DM_MSG *p_data){

...

        result.status = BTM_StartInquiry(   (tBTM_INQ_PARMS*)&p_data->search.inq_params,

                        bta_dm_inq_results_cb,

                        (tBTM_CMPL_CB*) bta_dm_inq_cmpl_cb);

...

}

我们看看bta_dm_inq_cmpl_cb的实现：

/*******************************************************************************

**

** Function         bta_dm_inq_cmpl_cb

**

** Description      Inquiry complete callback from BTM

**

** Returns          void

**

*******************************************************************************/

static void bta_dm_inq_cmpl_cb (void * p_result)

{

    tBTA_DM_MSG * p_msg;

    if (bta_dm_search_cb.cancel_pending == FALSE)

    {

        p_msg = (tBTA_DM_MSG *) GKI_getbuf(sizeof(tBTA_DM_MSG));

            p_msg->inq_cmpl.hdr.event = BTA_DM_INQUIRY_CMPL_EVT;

            p_msg->inq_cmpl.num = ((tBTM_INQUIRY_CMPL *)p_result)->num_resp;

            bta_sys_sendmsg(p_msg);

            }

这里发现是组建了一个msg，然后发送到btu 线程：

p_msg->inq_cmpl.hdr.event = BTA_DM_INQUIRY_CMPL_EVT;

p_msg->inq_cmpl.num = ((tBTM_INQUIRY_CMPL *)p_result)->num_resp;

    BTA_DM_API_SEARCH_EVT = BTA_SYS_EVT_START(BTA_ID_DM_SEARCH),

    BTA_DM_API_SEARCH_CANCEL_EVT,

    BTA_DM_API_DISCOVER_EVT,

    BTA_DM_INQUIRY_CMPL_EVT,//0x203

...

处理该event 是handler是：

static const tBTA_SYS_REG bta_dm_search_reg =

{

    bta_dm_search_sm_execute,

    bta_dm_search_sm_disable

};

bta_dm_search_sm_execute：

BOOLEAN bta_dm_search_sm_execute(BT_HDR *p_msg)

{

    tBTA_DM_ST_TBL      state_table;

    UINT8               action;

    int                 i;

/* look up the state table for the current state */

    state_table = bta_dm_search_st_tbl[bta_dm_search_cb.state];

    bta_dm_search_cb.state = state_table[p_msg->event & 0x00ff][BTA_DM_SEARCH_NEXT_STATE];

    /* execute action functions */

    for (i = ; i < BTA_DM_SEARCH_ACTIONS; i++)

    {

        if ((action = state_table[p_msg->event & 0x00ff][i]) != BTA_DM_SEARCH_IGNORE)

        {

            (*bta_dm_search_action[action])( (tBTA_DM_MSG*) p_msg);

        }

    }

    return TRUE;

}

他的处理流程是先找到该状态的table，然后赋值下一个状态，然后根据event 在table中查找该事件应该执行的action，这些action 有函数和他们一一对应，执行这些函数就行。

我们当前的状态是bta_dm_search_search_active_st_table，需要执行的action = BTA_DM_INQUIRY_CMPL，下一个状态依然是BTA_DM_SEARCH_ACTIVE 　　

我们看看BTA_DM_INQUIRY_CMPL 对应的函数是什么？

/* action function list */

const tBTA_DM_ACTION bta_dm_search_action[] =

{

  bta_dm_search_start,              /* 0 BTA_DM_API_SEARCH */

  bta_dm_search_cancel,             /* 1 BTA_DM_API_SEARCH_CANCEL */

  bta_dm_discover,                  /* 2 BTA_DM_API_DISCOVER */

  bta_dm_inq_cmpl,                  /* 3 BTA_DM_INQUIRY_CMPL */

  bta_dm_rmt_name,                  /* 4 BTA_DM_REMT_NAME */

看看回调函数的具体实现：

/*******************************************************************************

**

** Function         bta_dm_inq_cmpl

**

** Description      Process the inquiry complete event from BTM

**

** Returns          void

**

*******************************************************************************/

void bta_dm_inq_cmpl (tBTA_DM_MSG *p_data)

{

    tBTA_DM_MSG * p_msg;

    tBTA_DM_SEARCH  data;

    APPL_TRACE_DEBUG("bta_dm_inq_cmpl");

    data.inq_cmpl.num_resps = p_data->inq_cmpl.num;

    bta_dm_search_cb.p_search_cback(BTA_DM_INQ_CMPL_EVT, &data);//执行回调，向上层通知

    if((bta_dm_search_cb.p_btm_inq_info = BTM_InqDbFirst()) != NULL)//如果搜索到设备了，对设备做discover的动作

    {

        /* start name and service discovery from the first device on inquiry result */

        bta_dm_search_cb.name_discover_done = FALSE;

        bta_dm_search_cb.peer_name[]       = ;

        bta_dm_discover_device(bta_dm_search_cb.p_btm_inq_info->results.remote_bd_addr);

    }

    else //否则结束，向上层传 BTA_DM_SEARCH_CMPL_EVT;

    {

        /* no devices, search complete */

        bta_dm_search_cb.services = ;

        if ((p_msg = (tBTA_DM_MSG *) GKI_getbuf(sizeof(tBTA_DM_MSG))) != NULL)

        {

            p_msg->hdr.event          = BTA_DM_SEARCH_CMPL_EVT;

            p_msg->hdr.layer_specific = BTA_DM_API_DISCOVER_EVT;

            bta_sys_sendmsg(p_msg);

        }

        }

    }

这一部分的内容也可以分为三部分：

bta_dm_search_cb.p_search_cback(BTA_DM_INQ_CMPL_EVT, &data);
有搜索到设备，进行discovery
没有搜索到设备，上报BTA_DM_SEARCH_CMPL_EVT

首先来看看第一部分：

3.1 bta_dm_search_cb.p_search_cback(BTA_DM_INQ_CMPL_EVT, &data);

bta_dm_search_cb.p_search_cback 在BTA_DmSearch 中赋值的，为bte_search_devices_evt ，我们看看其实现：

/*******************************************************************************

**

** Function         bte_search_devices_evt

**

** Description      Switches context from BTE to BTIF for DM search events

**

** Returns          void

**

*******************************************************************************/

static void bte_search_devices_evt(tBTA_DM_SEARCH_EVT event, tBTA_DM_SEARCH *p_data)

{

    UINT16 param_len = ;

...

    btif_transfer_context (btif_dm_search_devices_evt , (UINT16) event, (void *)p_data, param_len,

        (param_len > sizeof(tBTA_DM_SEARCH)) ? search_devices_copy_cb : NULL);

}

发现其直接被transfer 到btif线程中执行btif_dm_search_devices_evt：

/******************************************************************************

**

** Function         btif_dm_search_devices_evt

**

** Description      Executes search devices callback events in btif context

**

** Returns          void

**

******************************************************************************/

static void btif_dm_search_devices_evt (UINT16 event, char *p_param)

{

    tBTA_DM_SEARCH *p_search_data;

    BTIF_TRACE_EVENT("%s event=%s", __FUNCTION__, dump_dm_search_event(event));

    switch (event)

    {

...

        case BTA_DM_INQ_CMPL_EVT://并没有进一步去通知上层

        {

#if (defined(BLE_INCLUDED) && (BLE_INCLUDED == TRUE))

            tBTA_DM_BLE_PF_FILT_PARAMS adv_filt_param;

            memset(&adv_filt_param, , sizeof(tBTA_DM_BLE_PF_FILT_PARAMS));

            BTA_DmBleScanFilterSetup(BTA_DM_BLE_SCAN_COND_DELETE, , &adv_filt_param, NULL,

                                     bte_scan_filt_param_cfg_evt, );

#endif

        }

         break;

        case BTA_DM_DISC_CMPL_EVT:

        {

            HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb, BT_DISCOVERY_STOPPED);//如果是BTA_DM_DISC_CMPL_EVT:会进一步通知上层

        }

        break;

这里发现，BTA_DM_INQ_CMPL_EVT:并不会一直往上面传，而 BTA_DM_DISC_CMPL_EVT:则是会上报给上层。那如果一直搜索不到设备就不会给上层答复吗？我们看看第三部分的行为。

3.2 有搜索到设备，进行discovery

再次贴上代码：

  if((bta_dm_search_cb.p_btm_inq_info = BTM_InqDbFirst()) != NULL)

    {

        /* start name and service discovery from the first device on inquiry result */

        bta_dm_search_cb.name_discover_done = FALSE;

        bta_dm_search_cb.peer_name[]       = ;

        bta_dm_discover_device(bta_dm_search_cb.p_btm_inq_info->results.remote_bd_addr);

    }

看代码的注释，是开始名字和service 的discovery 的工作。看看这个函数的实现：

首先简述一下该函数的作用：

判断是否需要去获取对端设备的名字。不需要跳过，需要就去获取名字并返回，这里猜想服务方面的搜索肯定是在获取名字返回的函数里面进行。
判断是否需要进行服务的搜索，需要则进行，从开始的discovery的接口看，应该是不需要进行服务的搜索。
发出服务完成的event，发送到btu 线程。

下面看代码：

/*******************************************************************************

**

** Function         bta_dm_discover_device

**

** Description      Starts name and service discovery on the device

**

** Returns          void

**

*******************************************************************************/

static void bta_dm_discover_device(BD_ADDR remote_bd_addr)

{

    tBTA_DM_MSG * p_msg;

    tBT_TRANSPORT transport = BT_TRANSPORT_BR_EDR;

#if BLE_INCLUDED == TRUE

    if (bta_dm_search_cb.transport == BTA_TRANSPORT_UNKNOWN)//一开始都是unkown，会BTM_ReadDevInfo来判断transport

    {

        tBT_DEVICE_TYPE dev_type;

        tBLE_ADDR_TYPE  addr_type;

        BTM_ReadDevInfo(remote_bd_addr, &dev_type, &addr_type);

        if (dev_type == BT_DEVICE_TYPE_BLE || addr_type == BLE_ADDR_RANDOM)

            transport = BT_TRANSPORT_LE;

    } else {

        transport = bta_dm_search_cb.transport;

    }

#endif

    /* Reset transport state for next discovery */

    bta_dm_search_cb.transport = BTA_TRANSPORT_UNKNOWN;//reset

    bdcpy(bta_dm_search_cb.peer_bdaddr, remote_bd_addr);

    if (bta_dm_search_cb.p_btm_inq_info)

    {

        APPL_TRACE_DEBUG("%s appl_knows_rem_name %d", __func__,

                            bta_dm_search_cb.p_btm_inq_info->appl_knows_rem_name);//显示app是否已经知道名字，这是inquiry db里面的数据

    }

    if((bta_dm_search_cb.p_btm_inq_info)

       && (bta_dm_search_cb.p_btm_inq_info->results.device_type == BT_DEVICE_TYPE_BLE)

       && (bta_dm_search_cb.state == BTA_DM_SEARCH_ACTIVE))

    {

        /* Do not perform RNR for LE devices at inquiry complete*/

        bta_dm_search_cb.name_discover_done = TRUE; //不要去查找LE 设备的名字

    }

    /* if name discovery is not done and application needs remote name */

    if ((!bta_dm_search_cb.name_discover_done)

       && (( bta_dm_search_cb.p_btm_inq_info == NULL )

            ||(bta_dm_search_cb.p_btm_inq_info && (!bta_dm_search_cb.p_btm_inq_info->appl_knows_rem_name))))//需要名字则进行名字的搜索

    {

        if (bta_dm_read_remote_device_name(bta_dm_search_cb.peer_bdaddr, transport) == TRUE)

            return;//返回

        /* starting name discovery failed */

        bta_dm_search_cb.name_discover_done = TRUE;

    }

    /* if application wants to discover service */

    if ( bta_dm_search_cb.services )//一般是0

    {

        /* initialize variables */

        bta_dm_search_cb.service_index      = ;

        bta_dm_search_cb.services_found     = ;

        bta_dm_search_cb.services_to_search = bta_dm_search_cb.services;

#if BLE_INCLUDED == TRUE && BTA_GATT_INCLUDED == TRUE

        bta_dm_search_cb.uuid_to_search     = bta_dm_search_cb.num_uuid;

#endif

        if ((bta_dm_search_cb.p_btm_inq_info != NULL) &&

            bta_dm_search_cb.services != BTA_USER_SERVICE_MASK

            &&(bta_dm_search_cb.sdp_search == FALSE))

        {

            /* check if EIR provides the information of supported services */

            bta_dm_eir_search_services( &bta_dm_search_cb.p_btm_inq_info->results,

                                        &bta_dm_search_cb.services_to_search,

                                        &bta_dm_search_cb.services_found );

        }

        /* if seaching with EIR is not completed */

        if(bta_dm_search_cb.services_to_search)

        {

            /* check whether connection already exists to the device

               if connection exists, we don't have to wait for ACL

               link to go down to start search on next device */

            if (BTM_IsAclConnectionUp(bta_dm_search_cb.peer_bdaddr, BT_TRANSPORT_BR_EDR))

                bta_dm_search_cb.wait_disc = FALSE;

            else

                bta_dm_search_cb.wait_disc = TRUE;

#if (BLE_INCLUDED == TRUE && (defined BTA_GATT_INCLUDED) && (BTA_GATT_INCLUDED == TRUE))

            if ( bta_dm_search_cb.p_btm_inq_info )

            {

                APPL_TRACE_DEBUG("%s p_btm_inq_info 0x%x results.device_type 0x%x services_to_search 0x%x",

                                    __func__,

                                    bta_dm_search_cb.p_btm_inq_info,

                                    bta_dm_search_cb.p_btm_inq_info->results.device_type,

                                    bta_dm_search_cb.services_to_search);

            }

            if (transport == BT_TRANSPORT_LE)

            {

                if (bta_dm_search_cb.services_to_search & BTA_BLE_SERVICE_MASK)

                {

                    //set the raw data buffer here

                    memset(g_disc_raw_data_buf, , sizeof(g_disc_raw_data_buf));

                    bta_dm_search_cb.p_ble_rawdata = g_disc_raw_data_buf;

                    bta_dm_search_cb.ble_raw_size = MAX_DISC_RAW_DATA_BUF;

                    bta_dm_search_cb.ble_raw_used = ;

                    /* start GATT for service discovery */

                    btm_dm_start_gatt_discovery(bta_dm_search_cb.peer_bdaddr);

                    return;

                }

            }

            else

#endif

            {

                bta_dm_search_cb.sdp_results = FALSE;

                bta_dm_find_services(bta_dm_search_cb.peer_bdaddr);

                return;

            }

        }

    }

    /* name discovery and service discovery are done for this device */

    if ((p_msg = (tBTA_DM_MSG *) GKI_getbuf(sizeof(tBTA_DM_MSG))) != NULL)

    {

        p_msg->hdr.event = BTA_DM_DISCOVERY_RESULT_EVT;//发送event到btu 线程

        /* initialize the data structure - includes p_raw_data and raw_data_size */

        memset(&(p_msg->disc_result.result), , sizeof(tBTA_DM_DISC_RES));

        p_msg->disc_result.result.disc_res.result = BTA_SUCCESS;

        p_msg->disc_result.result.disc_res.services = bta_dm_search_cb.services_found;

        bdcpy (p_msg->disc_result.result.disc_res.bd_addr, bta_dm_search_cb.peer_bdaddr);

        BCM_STRNCPY_S((char*)p_msg->disc_result.result.disc_res.bd_name,  sizeof(BD_NAME),

                      (char*)bta_dm_search_cb.peer_name, (BD_NAME_LEN-));

        /* make sure the string is terminated */

        p_msg->disc_result.result.disc_res.bd_name[BD_NAME_LEN-] = ;

        bta_sys_sendmsg(p_msg);

    }

}

服务方面 ok了之后是会向btu 线程发送event:

p_msg->hdr.event = BTA_DM_DISCOVERY_RESULT_EVT;
p_msg->disc_result.result.disc_res.result = BTA_SUCCESS;
p_msg->disc_result.result.disc_res.services = bta_dm_search_cb.services_found;
bdcpy (p_msg->disc_result.result.disc_res.bd_addr, bta_dm_search_cb.peer_bdaddr);

BTA_DM_DISCOVERY_RESULT_EVT = 0x207

执行的action = BTA_DM_SEARCH_RESULT，对应的函数是bta_dm_search_result，看看其具体的实现:

/*******************************************************************************

**

** Function         bta_dm_search_result

**

** Description      Service discovery result while searching for devices

**

** Returns          void

**

*******************************************************************************/

void bta_dm_search_result (tBTA_DM_MSG *p_data)

{

    /* call back if application wants name discovery or found services that application is searching */

    if (( !bta_dm_search_cb.services )

      ||(( bta_dm_search_cb.services ) && ( p_data->disc_result.result.disc_res.services )))

    {

        bta_dm_search_cb.p_search_cback(BTA_DM_DISC_RES_EVT, &p_data->disc_result.result);//回调

    }

    /* if searching did not initiate to create link */

    if(!bta_dm_search_cb.wait_disc )//如果没有pending

    {

        /* if service searching is done with EIR, don't search next device */

        if( bta_dm_search_cb.p_btm_inq_info )

        bta_dm_discover_next_device();//去搜索下一个设备的服务

    }

    else

    {

        /* wait until link is disconnected or timeout */

        bta_dm_search_cb.sdp_results = TRUE;

        bta_dm_search_cb.search_timer.p_cback = (TIMER_CBACK*)&bta_dm_search_timer_cback;

        bta_sys_start_timer(&bta_dm_search_cb.search_timer, , *(L2CAP_LINK_INACTIVITY_TOUT+) );//如果pending了，那么设置定时器，并且在回调函数里面继续执行搜索下一个设备的服务

    }

}

这里简单分析两点：

bta_dm_search_cb.p_search_cback(BTA_DM_DISC_RES_EVT, &p_data->disc_result.result)　　
bta_dm_discover_next_device，如果有数据库里面还有设备的话，那么继续搜索服务，如果没有设备的话，向上面传：BTA_DM_SEARCH_CMPL_EVT，最终也会上报到java层。前面已经分析过。‘

分析一下bta_dm_search_cb.p_search_cback,我们又遇到这个函数了，其实是bte_search_devices_evt-->btif_dm_search_devices_evt:

/******************************************************************************

**

** Function         btif_dm_search_devices_evt

**

** Description      Executes search devices callback events in btif context

**

** Returns          void

**

******************************************************************************/

static void btif_dm_search_devices_evt (UINT16 event, char *p_param)

{

    tBTA_DM_SEARCH *p_search_data;

    switch (event)

    {

        case BTA_DM_DISC_RES_EVT:

        {

            p_search_data = (tBTA_DM_SEARCH *)p_param;

            /* Remote name update */

            if (strlen((const char *) p_search_data->disc_res.bd_name))//如果早先已经知道了名字，这里的名字的长度0

            {

                bt_property_t properties[];

                bt_bdaddr_t bdaddr;

                bt_status_t status;

                properties[].type = BT_PROPERTY_BDNAME;

                properties[].val = p_search_data->disc_res.bd_name;

                properties[].len = strlen((char *)p_search_data->disc_res.bd_name);

                bdcpy(bdaddr.address, p_search_data->disc_res.bd_addr);

                status = btif_storage_set_remote_device_property(&bdaddr, &properties[]);

                ASSERTC(status == BT_STATUS_SUCCESS, "failed to save remote device property", status);

                HAL_CBACK(bt_hal_cbacks, remote_device_properties_cb,

                                 status, &bdaddr, , properties);

            }

现在简单看下：bta_dm_discover_next_device：

/*******************************************************************************

**

** Function         bta_dm_discover_next_device

**

** Description      Starts discovery on the next device in Inquiry data base

**

** Returns          void

**

*******************************************************************************/

static void bta_dm_discover_next_device(void)

{

    tBTA_DM_MSG * p_msg;

    /* searching next device on inquiry result */

    if((bta_dm_search_cb.p_btm_inq_info = BTM_InqDbNext(bta_dm_search_cb.p_btm_inq_info)) != NULL)

    {

        bta_dm_search_cb.name_discover_done = FALSE;

        bta_dm_search_cb.peer_name[]       = ;

        bta_dm_discover_device(bta_dm_search_cb.p_btm_inq_info->results.remote_bd_addr);//继续搜索服务

    }

    else

    {

        /* no devices, search complete */

        bta_dm_search_cb.services = ;

        if ((p_msg = (tBTA_DM_MSG *) GKI_getbuf(sizeof(tBTA_DM_MSG))) != NULL)

        {

            p_msg->hdr.event          = BTA_DM_SEARCH_CMPL_EVT;//都搜索我弄成之后上报event，结束discovery的流程

            p_msg->hdr.layer_specific = BTA_DM_API_DISCOVER_EVT;

            bta_sys_sendmsg(p_msg);

        }

    }

}

服务搜索部分就介绍到这里。

3.3 没有搜索到设备或者搜索完成，上报BTA_DM_SEARCH_CMPL_EVT

再附上这段代码：

    {

        /* no devices, search complete */

        bta_dm_search_cb.services = ;

        if ((p_msg = (tBTA_DM_MSG *) GKI_getbuf(sizeof(tBTA_DM_MSG))) != NULL)

        {

            p_msg->hdr.event          = BTA_DM_SEARCH_CMPL_EVT;

            p_msg->hdr.layer_specific = BTA_DM_API_DISCOVER_EVT;

            bta_sys_sendmsg(p_msg);

        }

这边还是组装了一个event：

p_msg->hdr.event = BTA_DM_SEARCH_CMPL_EVT;
p_msg->hdr.layer_specific = BTA_DM_API_DISCOVER_EVT;

相应的log也就是：BTA got event 0x206

const tBTA_DM_ACTION bta_dm_search_action[] =

{

  bta_dm_search_start,              /* 0 BTA_DM_API_SEARCH */

  bta_dm_search_cancel,             /* 1 BTA_DM_API_SEARCH_CANCEL */

  bta_dm_discover,                  /* 2 BTA_DM_API_DISCOVER */

  bta_dm_inq_cmpl,                  /* 3 BTA_DM_INQUIRY_CMPL */

  bta_dm_rmt_name,                  /* 4 BTA_DM_REMT_NAME */

  bta_dm_sdp_result,                /* 5 BTA_DM_SDP_RESULT */

  bta_dm_search_cmpl,               /* 6 BTA_DM_SEARCH_CMPL */

执行的就是bta_dm_search_cmpl：

/*******************************************************************************

**

** Function         bta_dm_search_cmpl

**

** Description      Sends event to application

**

** Returns          void

**

*******************************************************************************/

void bta_dm_search_cmpl (tBTA_DM_MSG *p_data)

{

    APPL_TRACE_EVENT("%s", __func__);

...

    if (p_data->hdr.layer_specific == BTA_DM_API_DI_DISCOVER_EVT)

        bta_dm_di_disc_cmpl(p_data);

    else

        bta_dm_search_cb.p_search_cback(BTA_DM_DISC_CMPL_EVT, NULL);

#endif

}

函数如注释阐明的那样：Sends event to application

我们前面已经分析过bta_dm_search_cb.p_search_cback=bte_search_devices_evt ，这次传入的事件是BTA_DM_DISC_CMPL_EVT

bte_search_devices_evt --->继续进入到btif_dm_search_devices_evt:

  /******************************************************************************

**

** Function         btif_dm_search_devices_evt

**

** Description      Executes search devices callback events in btif context

**

** Returns          void

**

******************************************************************************/

static void btif_dm_search_devices_evt (UINT16 event, char *p_param)

{

    tBTA_DM_SEARCH *p_search_data;

    BTIF_TRACE_EVENT("%s event=%s", __FUNCTION__, dump_dm_search_event(event));

    switch (event)

    {

...

    case BTA_DM_DISC_CMPL_EVT:

        {

            HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb, BT_DISCOVERY_STOPPED);

        }

        break;

...

这一段其实再第一部分已经分析过，当传入的事件是BTA_DM_DISC_CMPL_EVT，那么就会调用：HAL_CBACK(bt_hal_cbacks, discovery_state_changed_cb, BT_DISCOVERY_STOPPED); 来通知上层。

其实也就是说，即便一条设备信息也搜索不到，那么也会发送BTA_DM_SEARCH_CMPL_EVT---->BTA_DM_DISC_CMPL_EVT --->调用HAL_CBACK：BT_DISCOVERY_STOPPED 来通知上层。

到这里 inquiry complete的流程就已经分析完毕了。

总结：

　　Inquiry Complete

update level busy，（btm_acl_update_busy_level）并不会上报到java层
执行bta_dm_inq_cmpl_cb
1. bta_dm_search_cb.p_search_cback(BTA_DM_INQ_CMPL_EVT, &data); 该函数不会通知上层，
2. 有搜索到设备，进行discovery
3. 没有搜索到设备，上报BTA_DM_SEARCH_CMPL_EVT ，并通知到上层。

码农公寓

1.btm_acl_update_busy_level

3.(p_inq_cb)((tBTM_INQUIRY_CMPL *) &p_inq->inq_cmpl_info) = bta_dm_inq_cmpl_cb

3.1 bta_dm_search_cb.p_search_cback(BTA_DM_INQ_CMPL_EVT, &data);

3.2 有搜索到设备，进行discovery

3.3 没有搜索到设备或者搜索完成，上报BTA_DM_SEARCH_CMPL_EVT

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