Linux内核-蓝牙驱动移植

来自华清远见研发中心
跳转至: 导航搜索

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。

59-1-1-1.png

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。

59-1-1-2.png

59-1-1-3.png

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

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
  1. 蓝牙设备树节点
  2. 参考文档:

    Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
    Documentation/devicetree/bindings/serial/st,stm32-usart.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usart3定义如下:

    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";
    };
    

    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。

    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:

    &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>;
        };
    };
    

    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:

    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 */
        };
    };
    
    
  3. RTC节点
  4. 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

    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:

    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";
    };
    

    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。

    参考stm32mp157f-dk2.dts对于rtc设备节点的描述,需增加内容如下:

    rtc {
     	  st,lsco = <RTC_OUT2_RMP>;
     	  pinctrl-0 = <&rtc_out2_rmp_pins_a>;
     	  pinctrl-names = "default";
              status = "okay";
    };
    

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

  1. 导入交叉编译工具链
  2. linux@ubuntu:$ source /opt/st/stm32mp1/3.1-openstlinux-5.4-dunfell-mp1-20-06-24/environment-setup-cortexa7t2hf-neon-vfpv4-ostl-linux-gnueabi
    
  3. 开启32.768KHz时钟
  4. 修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件中的rtc节点添加如下内容:

    rtc {

    st,lsco = <RTC_OUT2_RMP>;
    pinctrl-0 = <&rtc_out2_rmp_pins_a>;
    pinctrl-names = "default";

    status = "okay";
    };

    其中红色字体部分为要添加的内容。

    添加rtc相关头文件。

    #include <dt-bindings/rtc/rtc-stm32.h>
    
  5. 添加usart3配置
  6. 修改arch/arm/boot/dts/stm32mp15xx-fsmp1x.dtsi文件,在文件末尾添加如下内容:

    &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>;
        };
    };
    
  7. 添加功能管脚配置
  8. 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。

    &pinctrl {
    ... ...

    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 */
    };
    };

    ... ...
    };


  9. 修改串口名称映射关系
  10. 修改arch/arm/dts/stm32mp157a-fsmp1a.dts文件,在aliases节点中添加如下内容:

    aliases{
    serial0 = &uart4;

    serial5 = &usart3;

    };

    其中红色字体部分为要添加的内容。

  11. 配置内核
  12. 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:

    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
    
  13. 编译内核及设备树
  14. linux@ubuntu:$ make -j4 uImage dtbs LOADADDR=0xC2000040
    
  15. 重启测试
  16. 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。

    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
    
    59-1-4-1.png