RK3588 USB蓝牙调试
一.蓝牙基本概念
蓝牙技术是一种无线通信的方式，利用特定频率的波段（2.4GHz-2.485GHz左右），进行电磁波传输。蓝牙传输原理是主从关系，一个主设备可以与7个蓝牙从设备配对。
二.蓝牙标准
蓝牙标准版本发展如下：
三.安卓蓝牙框架
libbt-vendor.so 完成对蓝牙模块硬件初始化与控制（物理通讯接口初始化，固件下载，供电控制）RK平台通过判断wifi+Bt模块的type，在libbuetooth_jni层选择加载不同适配厂商协议栈；并在libbt-hci中根据模块类型加载不同厂家模块的libbt-vendor.so，完成动态适配模块。
libbluetooth主要是bluedroid的蓝牙协议栈的具体实现，向下调用libbt-hci的接口加载**libbt-vendor；**向上供libblueooth_jni的回调；
bluetooth.apk 作 为 蓝 牙 服 务 进 程 ， 通 过 libblueooth_jni 层 获 取bluetooth*.default.so 提 供 的bt_interface_t 控 制 接 口 并 状 态 与 数 据 回 调 注 册 到bluetooth*.default.so；完成对蓝牙模块的控制与数据接收；
四.USB 蓝牙模块的调试
kernel部分
首先，将Realtek提供的蓝牙驱动文件rtk_btusb.h和rtk_btusb.c拷贝到kernel的drivers/bluetooth/目录下：
kernel-5.10/drivers/bluetooth/rtk_btusb.c
kernel-5.10/drivers/bluetooth/rtk_btusb.h
修改kernel的drivers/bluetooth/目录下的文件“Kconfig” 和“Makefile”
config BT_RTKBTUSB
tristate "RTK HCI USB driver"
depends on USB
help
RTK Bluetooth HCI USB driver
obj-$(CONFIG_BT_RTKBTUSB) += rtk_btusb.o
平台对应的defconfig文件添加Realtek BT Chip支持的宏定义，或者在 kernel 中make menuconfig选中rtk_btusb driver相关的宏。
CONFIG_BT_RTKBTUSB=y
libbt-vendor.so的配置
在hardware/realtek目录：HAL层添加蓝牙协议栈的代码和对应的libbt-vendor.so的源代码，libbt-vendor完成对蓝牙模块硬件初始化与控制（物理通讯接口初始化，固件下载，供电控制）
@sw-eng:RK3588S$ cd hardware/realtek/rtkbt/vendor/firmware
@sw-eng:firmware$
@sw-eng:firmware$ ls
BT_Firmware.mk rtl8723a_fw rtl8723c_fw rtl8723f_config rtl8761at_config rtl8761cs_fw rtl8822bs_config
fw_info.txt rtl8723as_config rtl8723cs_cg_config rtl8723f_fw rtl8761at_fw rtl8821a_config rtl8822bs_fw
readme.txt rtl8723as_fw rtl8723cs_cg_fw rtl8723fs_config rtl8761au8192ee_fw rtl8821a_fw rtl8822c_config
rtl8703as_config rtl8723b_config rtl8723cs_vf_config rtl8723fs_fw rtl8761au8812ae_fw rtl8821as_config rtl8822c_fw
rtl8703as_fw rtl8723b_config_2Ant_S0 rtl8723cs_vf_fw rtl8725a_config rtl8761au_fw rtl8821as_fw rtl8822cs_config
rtl8703bs_config rtl8723b_fw rtl8723cs_xx_config rtl8725a_fw rtl8761aw8192eu_config rtl8821c_config rtl8822cs_fw
rtl8703bs_fw rtl8723bs_config rtl8723cs_xx_fw rtl8725as_config rtl8761aw8192eu_fw rtl8821c_fw rtl8852as_config
rtl8703cs_config rtl8723bs_fw rtl8723d_config rtl8725as_fw rtl8761b_config rtl8821cs_config rtl8852as_fw
rtl8703cs_fw rtl8723bs_VQ0_config rtl8723d_fw rtl8761a_config rtl8761b_fw rtl8821cs_fw rtl8852au_config
rtl8723a_config rtl8723bs_VQ0_fw rtl8723ds_config rtl8761at8192ee_fw rtl8761bt_config rtl8822b_config rtl8852au_fw
rtl8723a_config_addr rtl8723bu_config rtl8723ds_fw rtl8761at8812ae_fw rtl8761bt_fw rtl8822b_fw
cfliu@sw-eng:firmware$
最终会通过mk文件hardware/realtek/rtkbt/rtkbt.mk拷贝到机器的以下目录，打开蓝牙的时候会去加载fw：
ifeq ($(strip $(TARGET_BOARD_PLATFORM_PRODUCT)), tablet)
BT_FIRMWARE_FILES := $(shell ls $(CUR_PATH)/vendor/firmware)
PRODUCT_COPY_FILES += \
$(foreach file, $(BT_FIRMWARE_FILES), $(CUR_PATH)/vendor/firmware/$(file):$(TARGET_COPY_OUT_VENDOR)/etc/firmware/$(file))
最终拷贝到设备上为：/vendor/etc/firmware
pro:/vendor/etc/firmware # ls
4343A0.hcd bcm4329.hcd fw_awnb108_ap.bin fw_bcm43438a0.bin fw_cyw43438.bin nvram_ap6212a.txt rtl8703bs_config rtl8723ds_config rtl8821a_fw
AP6275P_NVRAM_V1.1_20200702.txt bcm43341b0.hcd fw_bcm40181a2.bin fw_bcm43438a0_apsta.bin fw_cyw43455.bin nvram_ap6214.txt rtl8703bs_fw rtl8723ds_fw rtl8821as_config
BCM20710A1.hcd bcm4339a0.hcd fw_bcm40181a2_apsta.bin fw_bcm43438a0_p2p.bin fw_info.txt nvram_ap6214a.txt rtl8703cs_config rtl8723f_config rtl8821as_fw
BCM4330B1.hcd bcm43438a0.hcd fw_bcm40183b2.bin fw_bcm43438a1.bin mali_csffw.bin nvram_ap6216.txt rtl8703cs_fw rtl8723f_fw rtl8821c_config
BCM4343A0.hcd bcm43438a1.hcd fw_bcm40183b2_ag.bin fw_bcm43438a1_apsta.bin nh660.hcd nvram_ap6233f.txt rtl8723a_config rtl8723fs_config rtl8821c_fw
BCM4343A1.hcd bcm4354a1.hcd fw_bcm40183b2_ag_apsta.bin fw_bcm43438a1_p2p.bin nvram.txt nvram_ap6236.txt rtl8723a_config_addr rtl8723fs_fw rtl8821cs_config
BCM4343B0.hcd clm_bcm43752a2_ag.blob fw_bcm40183b2_ag_p2p.bin fw_bcm43455c0_ag.bin nvram_4330.txt nvram_ap6255.txt rtl8723a_fw rtl8725a_config rtl8821cs_fw
BCM4345C0.hcd clm_bcm43752a2_pcie_ag.blob fw_bcm40183b2_apsta.bin fw_bcm43455c0_ag_apsta.bin nvram_4330_oob.txt nvram_ap6256.txt rtl8723as_config rtl8725a_fw rtl8822b_config
BCM4345C5.hcd clm_bcm4375b4_pcie_ag.blob fw_bcm40183b2_p2p.bin fw_bcm43455c0_ag_p2p.bin nvram_AP6181.txt nvram_ap6275hh3.txt rtl8723as_fw rtl8725as_config rtl8822b_fw
BCM4354A2.hcd config.txt fw_bcm43241b4_ag.bin fw_bcm43456c5_ag.bin nvram_AP6210.txt nvram_ap6275s.txt rtl8723b_config rtl8725as_fw rtl8822bs_config
BCM4356A2.hcd esp32 fw_bcm43241b4_ag_apsta.bin fw_bcm43456c5_ag_apsta.bin nvram_AP6210_24M.txt nvram_ap62x2.txt rtl8723b_config_2Ant_S0 rtl8761a_config rtl8822bs_fw
BCM4359C0.hcd fw_RK901.bin fw_bcm43241b4_ag_p2p.bin fw_bcm4354a1_ag.bin nvram_AP6234.txt nvram_ap6354.txt rtl8723b_fw rtl8761at8192ee_fw rtl8822c_config
BCM4362A2.hcd fw_RK901a0.bin fw_bcm4330.bin fw_bcm4354a1_ag_apsta.bin nvram_AP6275P.txt nvram_ap6356.txt rtl8723bs_VQ0_config rtl8761at8812ae_fw rtl8822c_fw
BCM4375B1.hcd fw_RK901a0_apsta.bin fw_bcm4330_apsta.bin fw_bcm4354a1_ag_p2p.bin nvram_AP6330.txt nvram_ap6356s.txt rtl8723bs_VQ0_fw rtl8761at_config rtl8822cs_config
BT_Firmware.mk fw_RK901a2.bin fw_bcm43341b0_ag.bin fw_bcm4356a2_ag.bin nvram_AP6335.txt nvram_ap6398s.txt rtl8723bs_config rtl8761at_fw rtl8822cs_fw
RT2870AP.dat fw_RK901a2_apsta.bin fw_bcm43341b0_ag_apsta.bin fw_bcm4356a2_ag_apsta.bin nvram_AP6441.txt nvram_ap6398sa.txt rtl8723bs_fw rtl8761au8192ee_fw rtl8852as_config
RT2870APCard.dat fw_RK901a2_p2p.bin fw_bcm43341b0_ag_p2p.bin fw_bcm4356a2_ag_p2p.bin nvram_AP6476.txt nvram_ap6452.txt rtl8723bu_config rtl8761au8812ae_fw rtl8852as_fw
RT2870STA.dat fw_RK903.bin fw_bcm4334b1_ag.bin fw_bcm4359c0_ag.bin nvram_AP6493.txt nvram_awnb108.txt rtl8723c_fw rtl8761au_fw rtl8852au_config
RT2870STACard.dat fw_RK903_ag.bin fw_bcm4334b1_ag_apsta.bin fw_bcm4359c0_ag_apsta.bin nvram_B23.txt nvram_azw256.txt rtl8723cs_cg_config rtl8761aw8192eu_config rtl8852au_fw
awnb108.hcd fw_RK903_ag_apsta.bin fw_bcm4334b1_ag_p2p.bin fw_bcm4359c0_ag_p2p.bin nvram_GB86302I.txt nvram_azw372.txt rtl8723cs_cg_fw rtl8761aw8192eu_fw ssv6051-sw.bin
bcm20710a1.hcd fw_RK903_ag_p2p.bin fw_bcm4339a0_ag.bin fw_bcm43752a2_ag.bin nvram_RK901.txt otp.bin.z77 rtl8723cs_vf_config rtl8761b_config ssv6051-wifi.cfg
bcm20710a1_24M.hcd fw_RK903_p2p.bin fw_bcm4339a0_ag_apsta.bin fw_bcm43752a2_ag_apsta.bin nvram_RK903.cal readme.txt rtl8723cs_vf_fw rtl8761b_fw wifi_efuse_8189e.map
bcm20710a1_26M.hcd fw_RK903b2.bin fw_bcm4339a0_ag_p2p.bin fw_bcm43752a2_pcie_ag.bin nvram_RK903.txt rk903.hcd rtl8723cs_xx_config rtl8761bt_config wifi_efuse_8723bs-vq0.map
bcm2076b1.hcd fw_RK903b2_apsta.bin fw_bcm43436b0.bin fw_bcm43752a2_pcie_ag_apsta.bin nvram_RK903_26M.cal rk903_26M.hcd rtl8723cs_xx_fw rtl8761bt_fw wifi_efuse_8723cs.map
bcm40183b2.hcd fw_RK903b2_p2p.bin fw_bcm43436b0_apsta.bin fw_bcm4375b4_pcie_ag.bin nvram_WL211.txt rtl8703as_config rtl8723d_config rtl8761cs_fw wifi_efuse_8723ds.map
bcm43241b4.hcd fw_awnb108.bin fw_bcm43436b0_p2p.bin fw_bcm4375b4_pcie_ag_apsta.bin nvram_ap6212.txt rtl8703as_fw rtl8723d_fw rtl8821a_config wifi_efuse_8821cs.map
根据type选择具体的vendor库
部分HAL层对应的libbt-vendor.so的源代码浅析：
首先是bluedroid 蓝牙协议栈libbt-hci【原生蓝牙协议栈】通过system/bt/hci/src/hci_layer_android.cc的hci_initialize函数，调用interfaces/bluetooth/1.0/default/vendor_interface.cc中的initialize函数，进而调用open函数打开对应so库。
//interfaces/bluetooth/1.0/default/vendor_interface.cc
static const char* VENDOR_LIBRARY_NAME = "libbt-vendor.so";
static const char* VENDOR_REALTEK_LIBRARY_NAME = "libbt-vendor-realtek.so";
static char wifi_type[64] = {0};
extern "C" int check_wifi_chip_type_string(char *type);
bool VendorInterface::Open(InitializeCompleteCallback initialize_complete_cb,
PacketReadCallback event_cb,
PacketReadCallback acl_cb,
PacketReadCallback sco_cb,
PacketReadCallback iso_cb) {
initialize_complete_cb_ = initialize_complete_cb;
char vendor_lib_name[32];
// Initialize vendor interface
if (wifi_type[0] == 0)
//获取当前wifi芯片的type加载不同的so库，目前这个接口有权限问题，待进一步分析
check_wifi_chip_type_string(wifi_type);
if ((0 == strncmp(wifi_type, "RTL", 3)) ||
(0 == strncmp(wifi_type, "SSV", 3))) { // for ssv6051 wifi + rtl8761 bt
//此时加载的是libbt-vendor-realtek.so
strcpy(vendor_lib_name, VENDOR_REALTEK_LIBRARY_NAME);
} else {
//此时加载的是libbt-vendor.so
strcpy(vendor_lib_name, VENDOR_LIBRARY_NAME);
}
ALOGD("%s: %s", __func__, vendor_lib_name);
lib_handle_ = dlopen(vendor_lib_name, RTLD_NOW);
if (!lib_handle_) {
ALOGE("%s unable to open %s (%s)", __func__, vendor_lib_name,
dlerror());
return false;
}
lib_interface_ = reinterpret_cast(
dlsym(lib_handle_, VENDOR_LIBRARY_SYMBOL_NAME));
if (!lib_interface_) {
ALOGE("%s unable to find symbol %s in %s (%s)", __func__,
VENDOR_LIBRARY_SYMBOL_NAME, vendor_lib_name, dlerror());
return false;
}
// Get the local BD address
uint8_t local_bda[BluetoothAddress::kBytes];
//获取本地的蓝牙地址
if (!BluetoothAddress::get_local_address(local_bda)) {
LOG_ALWAYS_FATAL("%s: No Bluetooth Address!", __func__);
}
//接口的初始化
int status = lib_interface_->init(&lib_callbacks, (unsigned char*)local_bda);
if (status) {
ALOGE("%s unable to initialize vendor library: %d", __func__, status);
return false;
}
ALOGD("%s vendor library loaded", __func__);
// Power on the controller
int power_state = BT_VND_PWR_ON;
lib_interface_->op(BT_VND_OP_POWER_CTRL, &power_state);
// Get the UART socket(s)
int fd_list[CH_MAX] = {0};
int fd_count = lib_interface_->op(BT_VND_OP_USERIAL_OPEN, &fd_list);
if (fd_count < 1 || fd_count > CH_MAX - 1) {
ALOGE("%s: fd_count %d is invalid!", __func__, fd_count);
return false;
}
for (int i = 0; i < fd_count; i++) {
if (fd_list[i] == INVALID_FD) {
ALOGE("%s: fd %d is invalid!", __func__, fd_list[i]);
return false;
}
}
event_cb_ = event_cb;
PacketReadCallback intercept_events = [this](const hidl_vec& event) {
HandleIncomingEvent(event);
};
if (fd_count == 1) {
hci::H4Protocol* h4_hci =
new hci::H4Protocol(fd_list[0], intercept_events, acl_cb, sco_cb, iso_cb);
fd_watcher_.WatchFdForNonBlockingReads(
fd_list[0], [h4_hci](int fd) { h4_hci->OnDataReady(fd); });
hci_ = h4_hci;
} else {
hci::MctProtocol* mct_hci =
new hci::MctProtocol(fd_list, intercept_events, acl_cb);
fd_watcher_.WatchFdForNonBlockingReads(
fd_list[CH_EVT], [mct_hci](int fd) { mct_hci->OnEventDataReady(fd); });
fd_watcher_.WatchFdForNonBlockingReads(
fd_list[CH_ACL_IN], [mct_hci](int fd) { mct_hci->OnAclDataReady(fd); });
hci_ = mct_hci;
}
// Initially, the power management is off.
lpm_wake_deasserted = true;
// Start configuring the firmware
//配置和加载Firmware
firmware_startup_timer_ = new FirmwareStartupTimer();
lib_interface_->op(BT_VND_OP_FW_CFG, nullptr);
return true;
}
协议栈的选择
//packages/apps/Bluetooth/jni/com_android_bluetooth_btservice_AdapterService.cpp
static void classInitNative(JNIEnv* env, jclass clazz) {
......
char type[64];
check_wifi_chip_type_string(type);
if (!strncmp(type, "RTL", 3)) { //加载rtl厂商对应的蓝牙协议栈的库：bluetooth_rtk.default.so
ALOGD("%s, load %s.default.so", __func__, BT_STACK_RTK_MODULE_ID);
err = hw_get_module(BT_STACK_RTK_MODULE_ID, (hw_module_t const**)&module);
} else { //加载原生的蓝牙协议栈的库：bluetooth.default.so
ALOGD("%s, load %s.default.so", __func__, id);
err = hw_get_module(id, (hw_module_t const**)&module);
}
}
//处理一些回调
const bt_vendor_callbacks_t lib_callbacks = {
sizeof(lib_callbacks), firmware_config_cb, sco_config_cb,
low_power_mode_cb, sco_audiostate_cb, buffer_alloc_cb,
buffer_free_cb, transmit_cb, epilog_cb,
a2dp_offload_cb};
} // namespace
//BT_STACK_RTK_MODULE_ID在./hardware/libhardware/include/hardware/bluetooth.h定义
五.在RK安装蓝牙调试工具验证
直接在浏览器搜索下载即可：
到BUMBLE这个设备，点击连接；
连上之后，就会看到4个蓝牙服务，实时日志里也会看到连接状态的提示；
