【Bluetooth】获取蓝牙地址的6种方法，及btnvtool工具使用

1.蓝牙地址获取
android P：
获取方法是bluetooth_address.cpp里面

vendor/qcom/proprietary/bluetooth/hidl_transport/bt/1.0/default/bluetooth_address.cpp

bool BluetoothAddress::GetLocalAddress(uint8_t *local_addr)
{
char property[PROPERTY_VALUE_MAX] = { 0 };
bool valid_bda = false;

// Get addr from vendor location
if (fetch_vendor_addr(local_addr)) {
valid_bda = true;
}
// Get local bdaddr storage path from a system property.
if (!valid_bda && property_get(PROPERTY_BT_BDADDR_PATH, property, NULL)) {
int addr_fd;

ALOGV("%s: Trying %s", __func__, property);

addr_fd = open(property, O_RDONLY);
if (addr_fd != -1) {
int bytes_read = read(addr_fd, property, kStringLength);
CHECK(bytes_read == kStringLength);
close(addr_fd);

// Null terminate the string.
property[kStringLength] = '';

// If the address is not all zeros, then use it.
const uint8_t zero_bdaddr[kBytes] = { 0, 0, 0, 0, 0, 0 };
if ((StringToBytes(property, local_addr)) &&
(memcmp(local_addr, zero_bdaddr, kBytes) != 0)) {
valid_bda = true;
le2bd(local_addr);
ALOGD("%s: Got Factory BDA %s", __func__, property);
　　}
　}
}

// No BDADDR found in the file. Look for BDA in a factory property.
if (!valid_bda && property_get(FACTORY_BDADDR_PROPERTY, property, NULL) &&
StringToBytes(property, local_addr)) {
valid_bda = true;
le2bd(local_addr);
}

// Check if address is stored @ Modem NV
if ((!valid_bda)&& property_get("persist.vendor.bluetooth.modem_nv_support",
property, "false") && (strcmp(property, "true") == 0))
{
ALOGV("%s: QMI initialization START ",__func__);
if(!tried_reading_modemnv_) {
int retry = 0;
while (retry < QMI_INIT_MAX_TRY) {
if (retry > 0)
sleep(QMI_INIT_RETRY_INTERVAL_SEC);
if (QmiDmsInit() == true) {
if (QmiDmsGetAddress(modem_bdaddr_) == true) {
char bdstr[kStringLength + 1];
ALOGE("Read MODEM_NV_BD_ADDR 0x%x 0x%x 0x%x 0x%x 0x%x 0x%x ",
modem_bdaddr_[0], modem_bdaddr_[1], modem_bdaddr_[2], modem_bdaddr_[3],
modem_bdaddr_[4], modem_bdaddr_[5]);
valid_bda = true;
read_addr_from_modemnv_ = true;
memcpy(local_addr, modem_bdaddr_, kBytes);

/* Convert to ascii, and store as a persistent property */
BytesToString(local_addr, bdstr);
if (property_set(PERSIST_BDADDR_PROPERTY, (char*)bdstr) < 0) {
ALOGE("%s: Failed to set MODEM_NV_BD_ADDR in prop %s", __func__,
PERSIST_BDADDR_PROPERTY);
　}
}
QmiDmsCleanup();
break;
}
++retry;
ALOGE("%s: QMI initialization failed in %d try...", __func__, retry);
}
tried_reading_modemnv_ = true;
} else if(read_addr_from_modemnv_) {
memcpy(local_addr, modem_bdaddr_, kBytes);
valid_bda = true;
　}
}

// No factory BDADDR found. Look for a previously stored BDA.
if (!valid_bda && property_get(PERSIST_BDADDR_PROPERTY, property, NULL) &&
StringToBytes(property, local_addr)) {
valid_bda = true;
le2bd(local_addr);
}

/* Generate new BDA if necessary */
if (!valid_bda) {
char bdstr[kStringLength + 1];
struct timespec cur_time;

if (-1 == clock_gettime (CLOCK_MONOTONIC, &cur_time))
{
ALOGE("%s: clock_gettime failed ", __func__);
}

srand((unsigned int)cur_time.tv_nsec);

/* No autogen BDA. Generate one now. */
local_addr[0] = 0x22;
local_addr[1] = 0x22;
local_addr[2] = (uint8_t)rand();
local_addr[3] = (uint8_t)rand();
local_addr[4] = (uint8_t)rand();
local_addr[5] = (uint8_t)rand();

/* Convert to ascii, and store as a persistent property */
BytesToString(local_addr, bdstr);

ALOGE("%s: No preset BDA! Generating BDA: %s for prop %s", __func__,
(char*)bdstr, PERSIST_BDADDR_PROPERTY);
ALOGE("%s: This is a bug in the platform! Please fix!", __func__);

if (property_set(PERSIST_BDADDR_PROPERTY, (char*)bdstr) < 0) {
ALOGE("%s: Failed to set random BDA in prop %s", __func__,
PERSIST_BDADDR_PROPERTY);
valid_bda = false;
} else {
valid_bda = true;
le2bd(local_addr);
　　}
}

return valid_bda;
}

在上面的代码中，一共有下面的 6 种获取mac地址的方法：

// Get addr from vendor location
// Get local bdaddr storage path from a system property.
// No BDADDR found in the file. Look for BDA in a factory property.
// Check if address is stored @ Modem NV
// No factory BDADDR found. Look for a previously stored BDA.
/* Generate new BDA if necessary */

其中，当需要从NV去读取Bluetooth的mac地址时，代码走// Check if address is stored @ Modem NV里面；
因为高通并没有在代码中做配置，所以需要我们去在device/qcom/common/common64.mk中添加
persist.vendor.bluetooth.modem_nv_support=true 

diff --git a/common64.mk b/common64.mk
--- a/common64.mk
+++ b/common64.mk
@@ -22,6 +22,7 @@ PRODUCT_PROPERTY_OVERRIDES +=
persist.vendor.radio.custom_ecc=1
persist.vendor.radio.rat_on=combine
persist.backup.ntpServer=0.pool.ntp.org
+ persist.vendor.bluetooth.modem_nv_support=true
sys.vendor.shutdown.waittime=500

2.btnvtool工具

adb root
adb shell

向nv里写入mac地址：
btnvtool -b 11.11.11.11.11.11　　或者，
btnvtool -b 22:22:22:22:22:22

读nv的mac地址：
btnvtool -p