libbluedroid.so

源代码位于 system/bluetooth/bluedroid/* ，编译完会生成库 libbluedroid.so.

1. init.rc 中的 “service btpwr /wl1271bt_enable /dev/ttyO1”

点击 Setting 里的 bluetooth，打开 bluetooth 后，系统会调用 bt_enable().

a. bt_enable().

int bt_enable() {
        LOGV(__FUNCTION__);
        int ret = -1;
        int hci_sock = -1;
        int attempt;
        if (set_bluetooth_power(1) < 0) goto out;     //这里会调用内核控制BT_EN,GPIO
        LOGI("Starting hciattach daemon");
        if (property_set("ctl.start", "hciattach") < 0) {  //通知 hciattach start
            LOGE("Failed to start hciattach");
            goto out;
        }
        // Try for 10 seconds, this can only succeed once hciattach has sent the
        // firmware and then turned on hci device via HCIUARTSETPROTO ioctl
        //重试1000次，等待wl1271 BT模块loadfirmware，再做出响应。
        for (attempt = 1000; attempt > 0; attempt--) {        
            hci_sock = create_hci_sock();        //这里用到了socket，看来得看看socket了
            if (hci_sock < 0) goto out;
            if (!ioctl(hci_sock, HCIDEVUP, HCI_DEV_ID)) {   //打开HCI, HCI DEV UP
                break;
            }
            close(hci_sock);
            usleep(10000); // 10 ms retry delay
        }
        if (attempt == 0) {
            LOGE("%s: Timeout waiting for HCI device to come up", __FUNCTION__);
            goto out;
        }
        LOGI("Starting bluetoothd deamon");
        if (property_set("ctl.start", "bluetoothd") < 0) {   //通知 bluetoothd start
            LOGE("Failed to start bluetoothd");
            goto out;
        }
        sleep(HCID_START_DELAY_SEC);
        ret = 0;
    out:
        if (hci_sock >= 0) close(hci_sock);
        return ret;
    }

b. set_bluetooth_power():

static int set_bluetooth_power(int on) {
        int sz;
        int fd = -1;
        int ret = -1;
        const char buffer = (on ? '1' : '0');
        if (rfkill_id == -1) {
            if (init_rfkill()) goto out;
        }
        fd = open(rfkill_state_path, O_WRONLY);  //打开 rfkill_state_path
        if (fd < 0) {
            LOGE("open(%s) for write failed: %s (%d)", rfkill_state_path,
                 strerror(errno), errno);
            goto out;
        }
        sz = write(fd, &buffer, 1);   //写入 rfkill 1
        if (sz < 0) {
            LOGE("write(%s) failed: %s (%d)", rfkill_state_path, strerror(errno),
                 errno);
            goto out;
        }
        ret = 0;
    out:
        if (fd >= 0) close(fd);
        return ret;
    }

c. create_hci_sock():

static inline int create_hci_sock() {
        int sk = socket(AF_BLUETOOTH, SOCK_RAW, BTPROTO_HCI);  //建立一个socket。
        if (sk < 0) {
            LOGE("Failed to create bluetooth hci socket: %s (%d)",
                 strerror(errno), errno);
        }
        return sk;
    }

还有其他一些函数：

d. bt_disable(),这个函数应该是蓝牙睡眠的时候调用的。

int bt_disable() {
        LOGV(__FUNCTION__);
        int ret = -1;
        int hci_sock = -1;
        LOGI("Stopping bluetoothd deamon");
        if (property_set("ctl.stop", "bluetoothd") < 0) {  //通知 bluetoothd stop
            LOGE("Error stopping bluetoothd");
            goto out;
        }
        usleep(HCID_STOP_DELAY_USEC);
        hci_sock = create_hci_sock();  //建立 hci socket
        if (hci_sock < 0) goto out;
        ioctl(hci_sock, HCIDEVDOWN, HCI_DEV_ID);  //关闭HCI， HCI DEV DOWN
        LOGI("Stopping hciattach deamon");
        if (property_set("ctl.stop", "hciattach") < 0) {
            LOGE("Error stopping hciattach");
            goto out;
        }
        if (set_bluetooth_power(0) < 0) {  //关闭蓝牙供电，BT_EN
            goto out;
        }
        ret = 0;
    out:
        if (hci_sock >= 0) close(hci_sock);
        return ret;
    }

e. bt_is_enabled():

int bt_is_enabled() {
        LOGV(__FUNCTION__);
        int hci_sock = -1;
        int ret = -1;
        struct hci_dev_info dev_info;
        // Check power first
        ret = check_bluetooth_power();   //check 蓝牙的供电
        if (ret == -1 || ret == 0) goto out;
        ret = -1;
        // Power is on, now check if the HCI interface is up
        hci_sock = create_hci_sock();
        if (hci_sock < 0) goto out;
        dev_info.dev_id = HCI_DEV_ID;  //HCI GET DEV INFO， 获取HCI信息
        if (ioctl(hci_sock, HCIGETDEVINFO, (void *)&dev_info) < 0) {
            ret = 0;
            goto out;
        }
        ret = hci_test_bit(HCI_UP, &dev_info.flags);
    out:
        if (hci_sock >= 0) close(hci_sock);
        return ret;
    }

f. check_bluetooth_power()

static int check_bluetooth_power() {
        int sz;
        int fd = -1;
        int ret = -1;
        char buffer;
        if (rfkill_id == -1) {
            if (init_rfkill()) goto out;    //init_rfkill
        }
        fd = open(rfkill_state_path, O_RDONLY);
        if (fd < 0) {
            LOGE("open(%s) failed: %s (%d)", rfkill_state_path, strerror(errno),
                 errno);
            goto out;
        }
        sz = read(fd, &buffer, 1);
        if (sz != 1) {
            LOGE("read(%s) failed: %s (%d)", rfkill_state_path, strerror(errno),
                 errno);
            goto out;
        }
        switch (buffer) {
        case '1':
            ret = 1;
            break;
        case '0':
            ret = 0;
            break;
        }
    out:
        if (fd >= 0) close(fd);
        return ret;
    }

g. init_rfkill():

static int init_rfkill() {
        char path[64];
        char buf[16];
        int fd;
        int sz;
        int id;
        for (id = 0; ; id++) {
            snprintf(path, sizeof(path), "/sys/class/rfkill/rfkill%d/type", id);
            fd = open(path, O_RDONLY);
            if (fd < 0) {
                LOGW("open(%s) failed: %s (%d)\n", path, strerror(errno), errno);
                return -1;
            }
            sz = read(fd, &buf, sizeof(buf));
            close(fd);
            if (sz >= 9 && memcmp(buf, "bluetooth", 9) == 0) {
                rfkill_id = id;
                break;
            }
        }
        asprintf(&rfkill_state_path, "/sys/class/rfkill/rfkill%d/state", rfkill_id);
        return 0;
    }

hciattach /system/bin/hciattach -n /dev/ttyO1 texas 3000000