刚调完rtl8821cs的wifi功能，项目需要打通蓝牙配网功能。
调试过程中遇到各种问题中间几乎放弃，倒腾了几天最后还是打通了，顺便记录下过程。
通信接口：SDIO @WiFi、Uart @BT;
工作频段：2.4G/5.8G +BT4.2;
rtl8821cs是一个蓝牙wifi二合一模块，wifi走的是sdio接口，支持2.4G，5G.
bt走的是uart接口 支持bluez blue-alsa开源协议。
一、内核配置编译
我的内核版本是kernel-4.4.55
配置如下
make menuconfig
<*> Networking Support-->
<*> Bluetooth subsystem support --->
Bluetooth device drivers --->
rtl8821cs 是uart接口的蓝牙
内核需要先配置如下两个配置项，如果是usb的接口则相应的配置usb的驱动支持即可。
在这里直接配置编译进内核，也可以配置成ko模块方便调试。
[*] UART (H4) protocol support
[*] Realtek Three-wire UART (H5) protocol support
------------------------------------------------------------------------------------------------------------------------------------+ | | | < > RTK HCI USB driver | | | | < > HCI USB driver | | | | < > HCI SDIO driver | | | | <*> HCI UART driver | | | | [*] UART (H4) protocol support | | | | [ ] BCSP protocol support | | | | [ ] Atheros AR300x serial support | | | | [ ] HCILL protocol support | | | | [*] Realtek Three-wire UART (H5) protocol support | | | | [ ] Three-wire UART (H5) protocol support | | | | [ ] Intel protocol support | | | | [ ] Broadcom protocol support | | | | [ ] Qualcomm Atheros protocol support | | | | < > HCI BCM203x USB driver | | | | < > HCI BPA10x USB driver | | | | < > HCI BlueFRITZ! USB driver | | | | < > HCI VHCI (Virtual HCI device) driver | | | | < > Broadcom Bluetooth Low Power Manager Support | | | | < > Broadcom Bluetooth Low Power Manager Support for AXP | | | | < > Broadcom Bluetooth Low Power Manager Support for remote control | | | | <*> Realtek Bluetooth Low Power Manager Support | | | | < > Marvell Bluetooth driver support
相关驱动代码在如下目录，
linux-4.4/drivers/bluetooth
二、蓝牙服务依赖包
1、dbus-1.10.4
2、bluez-5.38
3、bluez-alsa-20180913
4、glib-2.50.1
uart接口需要hciattach工具，bluez里面已经自带了，但是rtk的需要专门的工具rtk_hciattach 才行，
故还需要如下依赖包
5、rtk_hciattach
同时还需要对应的fireware版本。
配置好后编译打包烧录，开始调试。
====================调试=============================
1、首先应该插入或者已经启动wifi驱动，保证模块已经上电。
2、先启动dbus服务，待会bluetoothd 起来需要羊刀dbus。
/etc/init.d/dbus start
启动后用ps查看dbus服务进程，
/usr/sbin/dbus-daemon --system
并且可以在/var/run/dbus/查看到通信端口
root@airfly:/# ll /var/run/dbus drwxr-xr-x 2 root root 60 Jan 2 14:31 . drwxr-xr-x 7 root root 240 Jan 2 14:33 .. srwxrwxrwx 1 root root 0 Jan 2 14:31 system_bus_socket
3、 使用rfkill 解除bluetooth的block
echo 0 > /sys/class/rfkill/rfkill0/state
echo 1 > /sys/class/rfkill/rfkill0/state
4、如果蓝牙驱动是ko模块，这时可以插入蓝牙驱动。
5、使用rtk_hciattach绑定uart端口
usb接口的蓝牙可以不用这一步。
rtk_hciattach -n -s 115200 /dev/ttyS1 rtk_h5 &
注意这个过程需要加载固件才行，如果固件不存在、不匹配或者错误就会失败。
root@airfly:/# rtk_hciattach -n -s 115200 /dev/ttyS1 rtk_h5 & root@airfly:/# Realtek Bluetooth init uart with init speed:115200, type:HCI UART H5 Realtek Bluetooth :Realtek hciattach version 3.1.0099684.20181218-163903 Realtek Bluetooth :Use epoll Realtek Bluetooth :[SYNC] Get SYNC Resp Pkt Realtek Bluetooth :[CONFIG] Get SYNC pkt Realtek Bluetooth :[CONFIG] Get CONFG pkt Realtek Bluetooth :[CONFIG] Get CONFG resp pkt Realtek Bluetooth :dic is 1, cfg field 0x14 Realtek Bluetooth :H5 init finished Realtek Bluetooth :Realtek H5 IC Realtek Bluetooth :Receive cmd complete event of command: 1001 Realtek Bluetooth :HCI Version 0x08 Realtek Bluetooth :HCI Revision 0x000c Realtek Bluetooth :LMP Subversion 0x8821 Realtek Bluetooth :Receive cmd complete event of command: fc6d Realtek Bluetooth :Read ROM version 01 Realtek Bluetooth :LMP Subversion 0x8821 Realtek Bluetooth :EVersion 1 Realtek Bluetooth :IC: RTL8821CS Realtek Bluetooth :Firmware/config: rtl8821cs_fw, rtl8821cs_config Realtek Bluetooth :Couldnt access customer BT MAC file /opt/bdaddr Realtek Bluetooth :Couldnt open extra config /opt/rtk_btconfig.txt, No such file or directory Realtek Bluetooth :Original Cfg len 25 Realtek Bluetooth :Config baudrate: 04928002 Realtek Bluetooth :uart flow ctrl: 0 Realtek Bluetooth :55 ab 23 87 13 00 0c 00 10 02 80 92 04 50 c5 ea Realtek Bluetooth :19 e1 1b fd af 5b 01 a4 0b Realtek Bluetooth :Cfg length 25 Realtek Bluetooth :Vendor baud from Config file: 04928002 Realtek Bluetooth :Load FW /lib/firmware/rtlbt/rtl8821cs_fw OK, size 40448 Realtek Bluetooth :rtb_get_fw_project_id: opcode 0, len 1, data 10 Realtek Bluetooth :FW version 0xaa7b2a21, Patch num 2 Realtek Bluetooth :Chip id 0x0001 Realtek Bluetooth :Chip id 0x0002 Realtek Bluetooth :Patch length 0x6078 Realtek Bluetooth :Start offset 0x00003d40 Realtek Bluetooth :Svn version: 20445 Realtek Bluetooth :Coexistence: BTCOEX_20180125-2828 Realtek Bluetooth :FW exists, Config file exists Realtek Bluetooth :Total len 24721 for fwc Realtek Bluetooth :baudrate in change speed command: 0x02 0x80 0x92 0x04 Realtek Bluetooth :Receive cmd complete event of command: fc17 Realtek Bluetooth :Received cc of vendor change baud Realtek Bluetooth :Final speed 1500000 Realtek Bluetooth :end_idx: 98, lp_len: 25, additional pkts: 1 Realtek Bluetooth :Start downloading... Realtek Bluetooth :Last packet 227 Realtek Bluetooth :Send last pkt Realtek Bluetooth :Disable host hw flow control Realtek Bluetooth :h5_hci_reset: Issue hci reset cmd Realtek Bluetooth :Receive cmd complete event of command: 0c03 Realtek Bluetooth :Received cc of hci reset cmd Realtek Bluetooth :Init Process finished Realtek Bluetooth post process Device setup complete
此时hci0蓝牙端口已经生成，如果是usb接口的不用hciattach就有端口，使用hciconfig工具可以查看端口及状态
当前应该还是DOWN状态
root@airfly:/# hciconfig
hci0: Type: BR/EDR Bus: UART
BD Address: 48:98:CA:AD:3C:AB ACL MTU: 1021:8 SCO MTU: 255:12
DOWN
RX bytes:1152 acl:0 sco:0 events:33 errors:0
TX bytes:814 acl:0 sco:0 commands:33 errors:0
6、启动hci0，状态更新为UP RUNNING
root@airfly:/# hciconfig hci0 up
root@airfly:/# hciconfig
hci0: Type: BR/EDR Bus: UART
BD Address: 48:98:CA:AD:3C:AB ACL MTU: 1021:8 SCO MTU: 255:12
UP RUNNING
RX bytes:2304 acl:0 sco:0 events:66 errors:0
TX bytes:1492 acl:0 sco:0 commands:67 errors:0
7、启动bluetoothd 服务
root@airfly:/# bluetoothd -n & root@airfly:/# bluetoothd[5559]: Bluetooth daemon 5.38 bluetoothd[5559]: Starting SDP server bluetoothd[5559]: Bluetooth management interface 1.10 initialized bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Error adding Link Loss service bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Current Time Service could not be registered bluetoothd[5559]: gatt-time-server: Input/output error (5) bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Not enough free handles to register service bluetoothd[5559]: Sap driver initialization failed. bluetoothd[5559]: sap-server: Operation not permitted (1)
如果dbus服务没有启动，bluetoothd启动会失败报错
root@airfly:/# bluetoothd -n bluetoothd[18793]: Bluetooth daemon 5.38 D-Bus setup failed: Failed to connect to socket /var/run/dbus/system_bus_socket: No such file or directory bluetoothd[18793]: Unable to get on D-Bus
bluetoothd启动需要加载一些配置文件在/etc/bluetooth下面。
root@airfly:/# ll /etc/bluetooth/*.conf -rw-r--r-- 1 root root 97 Jun 11 2020 /etc/bluetooth/hcidump.conf -rw-r--r-- 1 root root 397 Jun 11 2020 /etc/bluetooth/input.conf -rw-r--r-- 1 root root 3872 Jun 11 2020 /etc/bluetooth/main.conf -rw-r--r-- 1 root root 120 Jun 11 2020 /etc/bluetooth/network.conf -rw-r--r-- 1 root root 258 Jun 11 2020 /etc/bluetooth/proximity.conf
其中main.conf里面有几个关键配置,蓝牙名称，支持的蓝牙协议类型，扫描发现及匹配的超时设置等。
[General] # Default adaper name # Defaults to 'BlueZ X.YZ' Name = AIRFLY_H3 # Default device class. Only the major and minor device class bits are # considered. Defaults to '0x000000'. Class = 0x000428 # How long to stay in discoverable mode before going back to non-discoverable # The value is in seconds. Default is 180, i.e. 3 minutes. # 0 = disable timer, i.e. stay discoverable forever DiscoverableTimeout = 0 # How long to stay in pairable mode before going back to non-discoverable # The value is in seconds. Default is 0. # 0 = disable timer, i.e. stay pairable forever PairableTimeout = 0 # Automatic connection for bonded devices driven by platform/user events. # If a platform plugin uses this mechanism, automatic connections will be # enabled during the interval defined below. Initially, this feature # intends to be used to establish connections to ATT channels. Default is 60. #AutoConnectTimeout = 60
8、启动blue-alsa daemo
建立一个audio sink支持蓝牙“”媒体音频“协议。
root@airfly:/# bluealsa -p a2dp-sink & root@airfly:/# bluetoothd[4788]: Endpoint registered: sender=:1.1 path=/A2DP/SBC/Sink/1
9、使能扫描可发现
root@airfly:/# hciconfig hci0 piscan
root@airfly:/# hciconfig
hci0: Type: BR/EDR Bus: UART
BD Address: 48:98:CA:AD:3C:AB ACL MTU: 1021:8 SCO MTU: 255:12
UP RUNNING PSCAN ISCAN
RX bytes:2635 acl:0 sco:0 events:81 errors:0
TX bytes:2773 acl:0 sco:0 commands:82 errors:0
hciconfig的功能还是很强大，具体使用命令查看--help帮助。
root@airfly:/# hciconfig --help
hciconfig - HCI device configuration utility
Usage:
hciconfig
hciconfig [-a] hciX [command ...]
Commands:
up Open and initialize HCI device
down Close HCI device
reset Reset HCI device
rstat Reset statistic counters
auth Enable Authentication
noauth Disable Authentication
encrypt Enable Encryption
noencrypt Disable Encryption
piscan Enable Page and Inquiry scan
noscan Disable scan
iscan Enable Inquiry scan
pscan Enable Page scan
ptype [type] Get/Set default packet type
lm [mode] Get/Set default link mode
lp [policy] Get/Set default link policy
name [name] Get/Set local name
class [class] Get/Set class of device
voice [voice] Get/Set voice setting
iac [iac] Get/Set inquiry access code
inqtpl [level] Get/Set inquiry transmit power level
inqmode [mode] Get/Set inquiry mode
inqdata [data] Get/Set inquiry data
inqtype [type] Get/Set inquiry scan type
inqparms [win:int] Get/Set inquiry scan window and interval
pageparms [win:int] Get/Set page scan window and interval
pageto [to] Get/Set page timeout
afhmode [mode] Get/Set AFH mode
sspmode [mode] Get/Set Simple Pairing Mode
aclmtu <mtu:pkt> Set ACL MTU and number of packets
scomtu <mtu:pkt> Set SCO MTU and number of packets
delkey <bdaddr> Delete link key from the device
oobdata Get local OOB data
commands Display supported commands
features Display device features
version Display version information
revision Display revision information
block <bdaddr> Add a device to the blacklist
unblock <bdaddr> Remove a device from the blacklist
lerandaddr <bdaddr> Set LE Random Address
leadv [type] Enable LE advertising
0 - Connectable undirected advertising (default)
3 - Non connectable undirected advertising
noleadv Disable LE advertising
lestates Display the supported LE states
至此，蓝牙服务已经建立，如果一切正常，用手机蓝牙可以扫描匹配了。
10、连接播放音频
当有设备连接播放音频的时候，可以用bluealsa-aplay 播放接收到的媒体音频（通话音频是另外的协议）。
root@airfly:/# bluetoothd[4788]: Endpoint registered: sender=:1.1 path=/A2DP/SBC/Sink/2 bluetoothd[4788]: /org/bluez/hci0/dev_54_92_09_F7_CE_92/fd0: fd(17) ready bluetoothd[4788]: Can't open input device: No such file or directory (2) bluetoothd[4788]: AVRCP: failed to init uinput for 54:92:09:F7:CE:92 root@airfly:/# bluealsa-aplay 54:92:09:F7:CE:92 &
另外================
还有一个好用的蓝牙调试工具
bluetoothctl
和网络服务类似，网络服务的服务端是wpa_supplicant，对应的有一个客户端wpa_clit，可以用来手动调试，连接网络等。
同样蓝牙服务的服务端是bluetood ，对应的也有一个蓝牙界的瑞士军刀bluetoothcl客户端，通过命令来调试。
启动bluetootctl，会自动连接到bluetoothd，进入命令界面自动显示当前的Controller信息，
包括地址，名称（main.conf配置的Name字段）
root@airfly:/# bluetoothctl [NEW] Controller 48:98:CA:AD:3C:AB AIRFLY_H3 [default] [bluetooth]#
输入show命令可以查看到更信息的信息
[bluetooth]# show
Controller 48:98:CA:AD:3C:AB
Name: AIRFLY_H3
Alias: AIRFLY_H3
Class: 0x040428
Powered: yes
Discoverable: yes
Pairable: yes
UUID: Audio Sink (0000110b-0000-1000-8000-00805f9b34fb)
UUID: A/V Remote Control (0000110e-0000-1000-8000-00805f9b34fb)
UUID: PnP Information (00001200-0000-1000-8000-00805f9b34fb)
UUID: A/V Remote Control Target (0000110c-0000-1000-8000-00805f9b34fb)
Modalias: usb:v1D6Bp0246d0526
Discovering: no
[bluetooth]#
这里可以看到当前Controller的详细信息
Name：名称 main.conf配置
Alias:别名 可以通过hciconfig hci0 name alias_name设置
Class:支持的蓝牙服务类型，注意这里显示的是0x040428和main.conf配置的0x000428不一致了，是因为我们启动了
bluealsa -p a2dp-sink
支持了
UUID: Audio Sink (0000110b-0000-1000-8000-00805f9b34fb)
服务 。
Discoverable：是否可以被扫描发现，如果打开了就是yes 如果没打开就是no
Pairable: 是否接受匹配 yes /no
更多命令支持查看help
[bluetooth]# help Available commands: list List available controllers show [ctrl] Controller information select <ctrl> Select default controller devices List available devices paired-devices List paired devices power <on/off> Set controller power pairable <on/off> Set controller pairable mode discoverable <on/off> Set controller discoverable mode agent <on/off/capability> Enable/disable agent with given capability default-agent Set agent as the default one set-scan-filter-uuids [uuid1 uuid2 ...] Set scan filter uuids set-scan-filter-rssi [rssi] Set scan filter rssi, and clears pathloss set-scan-filter-pathloss [pathloss] Set scan filter pathloss, and clears rssi set-scan-filter-transport [transport] Set scan filter transport set-scan-filter-clear Clears discovery filter. scan <on/off> Scan for devices info [dev] Device information pair [dev] Pair with device trust [dev] Trust device untrust [dev] Untrust device block [dev] Block device unblock [dev] Unblock device remove <dev> Remove device connect <dev> Connect device disconnect [dev] Disconnect device list-attributes [dev] List attributes select-attribute <attribute> Select attribute attribute-info [attribute] Select attribute read Read attribute value write <data=[xx xx ...]> Write attribute value notify <on/off> Notify attribute value register-profile <UUID ...> Register profile to connect unregister-profile Unregister profile version Display version quit Quit program
我们可以进行打开关闭扫描发现，扫描蓝牙设备，匹配蓝牙设备，连接蓝牙设备，移除蓝牙设备等操作。
scan on scan off pair 54:92:09:F7:CE:92 connect 54:92:09:F7:CE:92 disconnect 54:92:09:F7:CE:92 remove 54:92:09:F7:CE:92
===================以下是踩坑爬坑过程=============================
1、bluetoothd启动后，无法发现蓝牙设备，设置了discoverable on也无效。
2、使用scan pair connect可以扫描匹配连其他蓝牙设备，并且可以播放音频。
3、已经连接且保持了第一个设备后，Controller可以被其他设备扫描到，可以匹配、连接、播放音乐、断开连接等操作。
4、如果第一个连接的设备断开了，后面连接的所有设备自动被断开，Controller又变得扫描不可见，无法被连接，也无法连接别人，需要重启机器才可以。
就这个问题倒腾了一个礼拜，内核驱动换了一遍，bluetoothd倒腾了一遍，最后更换了rtl8821cs的固件才突然好了。
rtl8821cs_fw
rtl8821cs_congig
杀千刀的模块固件有问题
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