RTL8821CU
一、蓝牙的架构
Android4.2 之后采用 bluedroid 作为协议;整体由 bluetooth.apk,bluedroid,libbt-vendor 三个 部 分 组 成 。
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;
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;
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)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。

RK 平台通过判断模块的 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。
二、适配USB蓝牙模块(RTL8821CU)
$PROJECT_TOP/kernel/drivers/bluetooth/rtk_btusb.c
49 static patch_info fw_patch_table[] = {
50 /* { vid, pid, lmp_sub_default, lmp_sub, everion, mp_fw_name, fw_name, config_name, fw_cache, fw_len, mac_offset } */
51 { 0x0BDA, 0x1724, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723A */
52 { 0x0BDA, 0x8723, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AE */
53 { 0x0BDA, 0xA723, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AE for LI */
54 { 0x0BDA, 0x0723, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AE */
55 { 0x13D3, 0x3394, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AE for Azurewave*/
56 { 0x0BDA, 0x0724, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AU */
57 { 0x0BDA, 0x8725, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AU */
58 { 0x0BDA, 0x872A, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AU */
59 { 0x0BDA, 0x872B, 0x1200, 0, 0, "mp_rtl8723a_fw", "rtl8723a_fw", "rtl8723a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* 8723AU */
60 { 0x0BDA, 0xb720, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723bu_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BU */
61 { 0x0BDA, 0xb72A, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723bu_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BU */
62 { 0x0BDA, 0xb728, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for LC */
63 { 0x0BDA, 0xb723, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
64 { 0x0BDA, 0xb72B, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
65 { 0x0BDA, 0xb001, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for HP */
66 { 0x0BDA, 0xb002, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
67 { 0x0BDA, 0xb003, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
68 { 0x0BDA, 0xb004, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
69 { 0x0BDA, 0xb005, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE */
70 { 0x13D3, 0x3410, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for Azurewave */
71 { 0x13D3, 0x3416, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for Azurewave */
72 { 0x13D3, 0x3459, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for Azurewave */
73 { 0x0489, 0xE085, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for Foxconn */
74 { 0x0489, 0xE08B, 0x8723, 0, 0, "mp_rtl8723b_fw", "rtl8723b_fw", "rtl8723b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8723BE for Foxconn */
75 { 0x0BDA, 0x2850, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AU */
76 { 0x0BDA, 0xA761, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AU only */
77 { 0x0BDA, 0x818B, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761aw8192eu_fw", "rtl8761aw8192eu_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AW + 8192EU */
78 { 0x0BDA, 0x818C, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761aw8192eu_fw", "rtl8761aw8192eu_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AW + 8192EU */
79 { 0x0BDA, 0x8760, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au8192ee_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AU + 8192EE */
80 { 0x0BDA, 0xB761, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AUV only */
81 { 0x0BDA, 0x8761, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au8192ee_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AU + 8192EE for LI */
82 { 0x0BDA, 0x8A60, 0x8761, 0, 0, "mp_rtl8761a_fw", "rtl8761au8812ae_fw", "rtl8761a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8761AU + 8812AE */
83 { 0x0BDA, 0x8821, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
84 { 0x0BDA, 0x0821, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
85 { 0x0BDA, 0x0823, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AU */
86 { 0x13D3, 0x3414, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
87 { 0x13D3, 0x3458, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
88 { 0x13D3, 0x3461, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
89 { 0x13D3, 0x3462, 0x8821, 0, 0, "mp_rtl8821a_fw", "rtl8821a_fw", "rtl8821a_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_1_2, MAX_PATCH_SIZE_24K}, /* RTL8821AE */
90 { 0x0BDA, 0xB822, 0x8822, 0, 0, "mp_rtl8822b_fw", "rtl8822b_fw", "rtl8822b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_24K}, /* RTL8822BE */
91 { 0x0BDA, 0xB82C, 0x8822, 0, 0, "mp_rtl8822b_fw", "rtl8822b_fw", "rtl8822b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_24K}, /* RTL8822BU */
92 { 0x0BDA, 0xB023, 0x8822, 0, 0, "mp_rtl8822b_fw", "rtl8822b_fw", "rtl8822b_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_24K}, /* RTL8822BE */
93 { 0x0BDA, 0xB703, 0x8703, 0, 0, "mp_rtl8723c_fw", "rtl8723c_fw", "rtl8723c_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_24K}, /* RTL8723CU */
94 /* todo: RTL8703BU */
95 { 0x0BDA, 0xD723, 0x8723, 0, 0, "mp_rtl8723d_fw", "rtl8723d_fw", "rtl8723d_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_40K}, /* RTL8723DU */
96 { 0x0BDA, 0xD720, 0x8723, 0, 0, "mp_rtl8723d_fw", "rtl8723d_fw", "rtl8723d_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_40K}, /* RTL8723DE */
97 { 0x0BDA, 0xB820, 0x8821, 0, 0, "mp_rtl8821c_fw", "rtl8821c_fw", "rtl8821c_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_40K}, /* RTL8821CU */
98 { 0x0BDA, 0xC820, 0x8821, 0, 0, "mp_rtl8821c_fw", "rtl8821c_fw", "rtl8821c_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_40K}, /* RTL8821CU */
99 { 0x0BDA, 0xC821, 0x8821, 0, 0, "mp_rtl8821c_fw", "rtl8821c_fw", "rtl8821c_config", NULL, 0 ,CONFIG_MAC_OFFSET_GEN_3PLUS, MAX_PATCH_SIZE_40K}, /* RTL8821CE */
100 /* todo: RTL8703CU */
101 /* NOTE: must append patch entries above the null entry */
102 { 0, 0, 0, 0, 0, NULL, NULL, NULL, NULL, 0, 0 }
103 };rtl8821c_fw.bin 和 rtl8821c_config 是 Realtek RTL8821CU 蓝牙功能所必须的固件文件
rtl8821c_fw和rtl8821c_config
1. rtl8821c_fw(或rtl8821c_fw.bin)
用途:RTL8821CU 蓝牙芯片在启动时会加载的主固件。
作用:驱动蓝牙 HCI 协议栈运行,比如设备发现、配对、音频传输(A2DP/HFP)等。
加载方式:由内核中的
rtk_btusb驱动通过request_firmware()加载进芯片。典型路径:
Android:
/vendor/firmware/rtlbt/rtl8821c_fw.bin或/vendor/etc/firmware/Linux:
/lib/firmware/rtlbt/rtl8821c_fw.bin
2. rtl8821c_config(或 rtl8821c_config.bin)
用途:提供蓝牙芯片的硬件配置参数,比如:
UART 波特率
天线增益
MAC 地址(有时)
格式:通常是二进制结构,由 Realtek 提供工具生成或裁剪。
加载方式:也通过
request_firmware(),一般先加载config,再加载fw.bin。典型路径:
Android:
/vendor/firmware/rtlbt/rtl8821c_configLinux:
/lib/firmware/rtlbt/rtl8821c_config
3. 是否必须?
4. 如何获取?
4.1. Realtek 官方代码仓库提取
4.2. 从友商安卓 SDK 里提取
某些安卓平台可能已有(比如全志、瑞芯微、友善之臂等 SDK):
find vendor/ -name "rtl8821c*"RK3566的安卓11SDK里包含这两个文件,分别位于
$PROJECT_TOP/hardware/realtek/rtkbt/vendor/firmware/rtl8821c_fw
$PROJECT_TOP/hardware/realtek/rtkbt/vendor/firmware/rtl8821c_configrtk_btusb.ko
1. 简介
rtk_btusb.ko 是 Realtek 官方为其蓝牙芯片(包括 RTL8821CU)提供的 蓝牙 USB 驱动内核模块,它是蓝牙功能能否正常工作的核心驱动之一。
2. 它具体做了什么?
当系统检测到 USB 设备 VID/PID 对应 Realtek 蓝牙芯片时:
2.1 rtk_btusb 驱动加载
比如检测到
0bda:c821(RTL8821CU 的 PID/VID)
2.2. 加载 config 与 firmware
驱动会执行:
request_firmware("rtl8821c_config", ...) request_firmware("rtl8821c_fw.bin", ...)这两个文件必须存在于
/vendor/firmware/rtlbt/或类似路径。
2.3. 初始化蓝牙控制器
配置波特率、MAC 地址、USB 端点等硬件参数
启动控制器工作模式,进入 HCI Ready 状态
2.4. 注册为 HCI 设备
被内核识别为
/sys/class/bluetooth/hci0用户空间可以通过
bluetoothd、hcitool等工具操作蓝牙
3. 驱动加载成功后会看到什么?
使用 dmesg 可以看到:
[ 10.321] Bluetooth: rtk_btusb: Realtek Bluetooth USB driver loaded
[ 10.322] Bluetooth: rtk_btusb: rtl8821cu found at USB port 2-1
[ 10.323] Bluetooth: rtk_btusb: Loading firmware rtlbt/rtl8821c_fw.bin
[ 10.324] Bluetooth: HCI device registered (hci0)还会看到 /dev 下的蓝牙设备,或者:
hciconfig
# 输出:
hci0: Type: Primary Bus: USB
BD Address: XX:XX:XX:XX:XX:XX ACL MTU: 1021:5 SCO MTU: 255:12
UP RUNNING PSCAN 4. 注意
rtk_btusb.ko通常放在:/vendor/lib/modules/rtk_btusb.ko并在
init.rc中用insmod加载,例如:insmod /vendor/lib/modules/rtk_btusb.ko必须配合 firmware 文件使用,否则会报错或蓝牙功能缺失。