查看“Linux内核-蓝牙驱动移植”的源代码

==实验原理==
FS-MP1A开发板蓝牙采用AP6236，WIFI蓝牙二合一芯片。蓝牙部分通过usart3与SoC进行数据交互。<br>

[[Image:59-1-1-1.png|640px]] <br>

蓝牙部分移需要配置usart3的设备树与AP_CK32KO管脚，可参考stm32mp157c-dk2.dts中的相关配置。<br>

[[Image:59-1-1-2.png]] <br>

[[Image:59-1-1-3.png]] <br>

查看原理图得出AP6236数据管脚与STM32MP157A的管脚对应关系如下：

{|class="wikitable"
|-
! 原理图网络编号 !! 对应管脚 !! 管脚功能 !! 管脚功能码
|-
| BT_UART_TX 
| PD8 
| USART3_TX
| AF7
|-
| BT_UART_RX 
| PD9 
| USART3_RX
| AF7
|-
| BT_UART_CTS 
| PD11 
| USART3_CTS
| AF7
|-
| BT_UART_RTS 
| PD12 
| USART3_RTS
| AF7
|-
| BT_WIFI_RST
| PD13 
| IO
| ANALOG
|-
| AP_CK32KO 
| PI8 
| RTC_OUT2
| ANALOG
|}
<ol>
<li>蓝牙设备树节点</li>

参考文档：
<pre><nowiki>
Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
Documentation/devicetree/bindings/serial/st,stm32-usart.txt
</nowiki></pre>
内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：
 arch/arm/boot/dts/stm32mp151.dtsi
stm32mp151中usart3定义如下：
<pre><nowiki>
usart3: serial@4000f000 {
    compatible = "st,stm32h7-uart";
    reg = <0x4000f000 0x400>;
    interrupts-extended = <&exti 28 IRQ_TYPE_LEVEL_HIGH>;
    clocks = <&rcc USART3_K>;
    resets = <&rcc USART3_R>;
    wakeup-source;
    power-domains = <&pd_core>;
    dmas = <&dmamux1 45 0x400 0x5>,
           <&dmamux1 46 0x400 0x1>;
    dma-names = "rx", "tx";
    status = "disabled";
};
</nowiki></pre>
上述代码只对usart3做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。<br>

参考文档或stm32mp157c-dk2.dts对于usart2设备节点的描述，增加usart3内容如下：
<pre><nowiki>
&usart3 {
    pinctrl-names = "default", "sleep", "idle";
    pinctrl-0 = <&usart3_pins_bt>;
    pinctrl-1 = <&usart3_idle_pins_bt>;
    pinctrl-2 = <&usart3_sleep_pins_bt>;
    uart-has-rtscts; 
    status = "okay";
        
    bluetooth {
        pinctrl-names = "default";
        pinctrl-0 = <&btreg0>;
        compatible = "brcm,bcm43438-bt";
        max-speed = <3000000>;
        vbat-supply = <&v3v3>;
        vddio-supply = <&v3v3>;
    };
};
</nowiki></pre>

同时stm32mp15-pinctrl.dtsi对于usart3的描述与FS-MP1A所使用管脚不一致，所以无法直接使用，需参考其增加如下内容：
<pre><nowiki>
usart3_pins_bt: usart3-bt-0 {
    pins1 {
       pinmux = <STM32_PINMUX('D', 8, AF7)>, /* USART3_TX */
              <STM32_PINMUX('D', 12, AF7)>; /* USART3_RTS */
       bias-disable;
       drive-push-pull;
       slew-rate = <0>;
    };
    pins2 {
       pinmux = <STM32_PINMUX('D', 9, AF7)>, /* USART3_RX */
              <STM32_PINMUX('D', 11, AF7)>; /* USART3_CTS_NSS */
       bias-disable;
    }; 
};

usart3_idle_pins_bt: usart3-idle-bt-0 {
    pins1 {
        pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
               <STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
               <STM32_PINMUX('D', 11, ANALOG)>; /* USART3_CTS_NSS */
    };
    pins2 {
        pinmux = <STM32_PINMUX('D', 9, AF7)>; /* USART3_RX */
        bias-disable;
    };
};

usart3_sleep_pins_bt: usart3-sleep-bt-0 {
    pins {
         pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
                <STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
                <STM32_PINMUX('D', 11, ANALOG)>, /* USART3_CTS_NSS */
                <STM32_PINMUX('D', 9, ANALOG)>; /* USART3_RX */
    };
};
</nowiki></pre>
<li>RTC节点</li>

AP6236需要使用一个外部输入的32.768KHz的时钟源，因此我们需要使能RTC的外部32.768KHz功能<br>

参考文档：
 Documentation/devicetree/bindings/rtc/st,stm32-rtc.txt
内核中ST对STM32MP15x系列芯片的设备树资源了做了定义，可参见：
 arch/arm/boot/dts/stm32mp151.dtsi
stm32mp151中rtc定义如下：
<pre><nowiki>
rtc: rtc@5c004000 {
    compatible = "st,stm32mp1-rtc";
    reg = <0x5c004000 0x400>;
    clocks = <&scmi0_clk CK_SCMI0_RTCAPB>,
         <&scmi0_clk CK_SCMI0_RTC>;
    clock-names = "pclk", "rtc_ck";
    interrupts-extended = <&exti 19 IRQ_TYPE_LEVEL_HIGH>;
    status = "disabled";
};
</nowiki></pre>
上述代码只对rtc做了基本的初始化，并没有针对不同的硬件设计做适配，所以需结合硬件补全设备树节点信息。<br>

参考stm32mp157f-dk2.dts对于rtc设备节点的描述，需增加内容如下：
<pre><nowiki>
rtc {
 	  st,lsco = <RTC_OUT2_RMP>;
 	  pinctrl-0 = <&rtc_out2_rmp_pins_a>;
 	  pinctrl-names = "default";
          status = "okay";
};
</nowiki></pre>
</ol>

==实验目的==
熟悉基于Linux操作系统下的蓝牙设备驱动移植配置过程。

==实验平台==
华清远见开发环境，FS-MP1A平台；

==实验步骤==
<ol>
<li>导入交叉编译工具链</li>
 linux@ubuntu:$ source /opt/st/stm32mp1/3.1-openstlinux-5.4-dunfell-mp1-20-06-24/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi
<li>开启32.768KHz时钟</li>

修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件中的rtc节点添加如下内容：

<div style="background-color:#F8F8F8;border:1px solid #E5E5E5;font-family: monospace,Courier;">
:rtc {<br>
<font color="#FF0000">
::  st,lsco = <RTC_OUT2_RMP>;
::  pinctrl-0 = <&rtc_out2_rmp_pins_a>;
::  pinctrl-names = "default";
</font>
::   status = "okay";
:};
</div>
其中红色字体部分为要添加的内容。<br>

添加rtc相关头文件。
 #include <dt-bindings/rtc/rtc-stm32.h>
<li>添加usart3配置</li>

修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件，在文件末尾添加如下内容：
<pre><nowiki>
&usart3 {
    pinctrl-names = "default", "sleep", "idle";
    pinctrl-0 = <&usart3_pins_bt>;
    pinctrl-1 = <&usart3_idle_pins_bt>;
    pinctrl-2 = <&usart3_sleep_pins_bt>;
    uart-has-rtscts; 
    status = "okay";
        
    bluetooth {
        shutdown-gpios =  <&gpiod 13 GPIO_ACTIVE_HIGH>;
        compatible = "brcm,bcm43438-bt";
        max-speed = <3000000>;
        vbat-supply = <&v3v3>;
        vddio-supply = <&v3v3>;
    };
};
</nowiki></pre>
<li>添加功能管脚配置</li>
要添加管脚配置需要有pinctrl节点，如果之前已经做了MIPI LCD移植或者RGB LCD则在arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件下找到pinctrl节点添加如下配置，如果之前没有做MIPI LCD移植或者RGB LCD那么需要新建一个pinctrl节点，然后添加如下配置。
<div style="background-color:#F8F8F8;border:1px solid #E5E5E5;font-family: monospace,Courier;">

:&pinctrl {
:	... ...
<font color="#FF0000">
::	usart3_pins_bt: usart3-bt-0 {
::		pins1 {
::		   pinmux = <STM32_PINMUX('D', 8, AF7)>, /* USART3_TX */
::				  <STM32_PINMUX('D', 12, AF7)>; /* USART3_RTS */
::		   bias-disable;
::		   drive-push-pull;
::		   slew-rate = <0>;
::		};
::		pins2 {
::		   pinmux = <STM32_PINMUX('D', 9, AF7)>, /* USART3_RX */
::				  <STM32_PINMUX('D', 11, AF7)>; /* USART3_CTS_NSS */
::		   bias-disable;
::		}; 
::	};
::
::	usart3_idle_pins_bt: usart3-idle-bt-0 {
::		pins1 {
::			pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
::				   <STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
::				   <STM32_PINMUX('D', 11, ANALOG)>; /* USART3_CTS_NSS */
::		};
::		pins2 {
::			pinmux = <STM32_PINMUX('D', 9, AF7)>; /* USART3_RX */
::			bias-disable;
::		};
::	};
::
::	usart3_sleep_pins_bt: usart3-sleep-bt-0 {
::		pins {
::			 pinmux = <STM32_PINMUX('D', 8, ANALOG)>, /* USART3_TX */
::					<STM32_PINMUX('D', 12, ANALOG)>, /* USART3_RTS */
::					<STM32_PINMUX('D', 11, ANALOG)>, /* ::USART3_CTS_NSS */
::					<STM32_PINMUX('D', 9, ANALOG)>; /* USART3_RX */
::		};
::	};
</font>
::	... ...
:};


</div>

<li>修改串口名称映射关系</li>

修改arch/arm/dts/stm32mp157a-fsmp1a.dts文件，在aliases节点中添加如下内容：
<div style="background-color:#F8F8F8;border:1px solid #E5E5E5;font-family: monospace,Courier;">
:aliases{<br>
::  serial0 = &uart4;
<font color="#FF0000">
::  serial5 = &usart3;
</font>
:};
</div>
其中红色字体部分为要添加的内容。<br>

<li>配置内核</li>

由于内核源码默认配置以及支持AP62xx，本节列出主要选项，如下：
<pre><nowiki>
linux@ubuntu:$ make menuconfig
Device Drivers  --->
	<*> Broadcom specific AMBA  --->
		[*]   Support for BCMA in a SoC
		[*]   ChipCommon-attached serial flash support
		[*]   BCMA Broadcom GBIT MAC COMMON core driver
		[*]   BCMA GPIO driver
</nowiki></pre>
<li>编译内核及设备树</li>
 linux@ubuntu:$ make -j4 uImage dtbs LOADADDR=0xC2000040
<li>重启测试</li>

将编译好的设备树和内核镜像拷贝到/tftpboot目录下，通过tftp引导内核，系统启动后查看/lib/firmware/brcm目录下是否包含BCM.hcd固件，如果没有发现这个文件可从【华清远见-FS_MP1A开发资料\02-程序源码\04-Linux系统移植\04-移植相关文件\02-Linux内核移植\AP6236固件】下拷贝到/lib/firmware/brcm目录下。<br>

开启蓝牙设备
 root@fsmp1a:# hciconfig hci0 up
查看设备地址
 root@fsmp1a:# hcitool dev
扫描蓝牙设备
 root@fsmp1a:# hcitool scan
[[Image:59-1-4-1.png]] <br>
</ol>