查看“Linux内核-Wi-Fi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。WiFi部分通过SDIO接口与SoC进行数据交互。<br>

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

在FS-MP1A开发板上sdmmc1用于连接sdcard，sdmmc2用于连接eMMC，sdmmc3则用于连接我们这里所用到的AP6236的WiFi接口。<br>

sdmmc3的设备树配置可参考stm32mp157c-dk2.dts中的相关配置，需要重新调整sdmmc3所使用的管脚，AP_CK32KO管脚配置和BT_WIFI_RST管脚配置。<br>

[[Image:60-1-1-2.png|320px]] 
[[Image:60-1-1-3.png|320px]] <br>

[[Image:60-1-1-4.png|320px]]
[[Image:59-1-1-3.png|320px]] <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
|-
| SD3_DATA0 
| PF0 
| SDMMC3_D0
| AF9
|-
| SD3_DATA1
| PF4 
| SDMMC3_D1
| AF9
|-
| SD3_DATA2
| PD5 
| SDMMC3_D2
| AF10
|-
| SD3_DATA3 
| PD7 
| SDMMC3_D3
| AF10
|-
| SD3_CMD 
| PD0 
| SDMMC3_CMD
| AF10
|-
| SD3_CLK 
| PG15 
| SDMMC3_CK
| AF10
|-
| WL_REG_ON 
| PD4 
| IO
| ANALOG
|-
| AP_CK32KO 
| PI8 
| RTC_OUT2
| ANALOG
|}
*WiFi设备树节点<br>

参考文档：
<pre><nowiki>
Documentation/devicetree/bindings/net/wireless/brcm,bcm43xx-fmac.txt
Documentation/devicetree/bindings/mmc/mmc.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sdmmc3定义如下：
<pre><nowiki>
sdmmc3: sdmmc@48004000 {
    compatible = "arm,pl18x", "arm,primecell";
    arm,primecell-periphid = <0x00253180>;
    reg = <0x48004000 0x400>, <0x48005000 0x400>;
    interrupts = <GIC_SPI 137 IRQ_TYPE_LEVEL_HIGH>;
    interrupt-names = "cmd_irq";
    clocks = <&rcc SDMMC3_K>;
    clock-names = "apb_pclk";
    resets = <&rcc SDMMC3_R>;
    cap-sd-highspeed;
    cap-mmc-highspeed;
    max-frequency = <120000000>;
    status = "disabled";
};
</nowiki></pre>
上述代码只对sdmmc3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sdmmc2设备节点的描述，增加sdmmc3内容如下：
<pre><nowiki>
&sdmmc3 {
    arm,primecell-periphid = <0x10153180>;
    pinctrl-names = "default", "opendrain", "sleep";
    pinctrl-0 = <&sdmmc3_b4_wifi_pins_a>;
    pinctrl-1 = <&sdmmc3_b4_od_wifi_pins_a>;
    pinctrl-2 = <&sdmmc3_b4_sleep_wifi_pins_a>;
    non-removable;
    st,neg-edge;
    bus-width = <4>;
    vmmc-supply = <&v3v3>;
    mmc-pwrseq = <&wifi_pwrseq>;
    #address-cells = <1>;
    #size-cells = <0>;
    keep-power-in-suspend;
    status = "okay";

    brcmf: bcrmf@1 {
        reg = <1>;
        compatible = "brcm,bcm4329-fmac";
    };
};
</nowiki></pre>
这里用到了一个mmc-pwrseq管脚用于控制AP6236的电源，可以stm32mp157c-dk2.dts对于wifi_pwrseq设备节点的描述，增加wifi_pwrseq内容如下：
<pre><nowiki>
wifi_pwrseq: wifi-pwrseq {
    compatible = "mmc-pwrseq-simple";
    reset-gpios = <&gpiod 4 GPIO_ACTIVE_LOW>;
};
</nowiki></pre>
stm32mp15-pinctrl.dtsi对于sdmmc3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>
sdmmc3_b4_wifi_pins_a: sdmmc3-b4-wifi-0 {
    pins1 {
        pinmux = <STM32_PINMUX('F', 0, AF9)>, /* SDMMC3_D0 */
             <STM32_PINMUX('F', 4, AF9)>, /* SDMMC3_D1 */
             <STM32_PINMUX('D', 5, AF10)>, /* SDMMC3_D2 */
             <STM32_PINMUX('D', 7, AF10)>, /* SDMMC3_D3 */
             <STM32_PINMUX('D', 0, AF10)>; /* SDMMC3_CMD */
        slew-rate = <1>;
        drive-push-pull;
        bias-pull-up;
    };
    pins2 {
        pinmux = <STM32_PINMUX('G', 15, AF10)>; /* SDMMC3_CK */
        slew-rate = <2>;
        drive-push-pull;
        bias-pull-up;
    };
};

sdmmc3_b4_od_wifi_pins_a: sdmmc3-b4-od-wifi-0 {
    pins1 {
        pinmux = <STM32_PINMUX('F', 0, AF9)>, /* SDMMC3_D0 */
             <STM32_PINMUX('F', 4, AF9)>, /* SDMMC3_D1 */
             <STM32_PINMUX('D', 5, AF10)>, /* SDMMC3_D2 */
             <STM32_PINMUX('D', 7, AF10)>; /* SDMMC3_D3 */
        slew-rate = <1>;
        drive-push-pull;
        bias-pull-up;
    };
    pins2 {
        pinmux = <STM32_PINMUX('G', 15, AF10)>; /* SDMMC3_CK */
        slew-rate = <2>;
        drive-push-pull;
        bias-pull-up;
    };
    pins3 {
        pinmux = <STM32_PINMUX('D', 0, AF10)>; /* SDMMC2_CMD */
        slew-rate = <1>;
        drive-open-drain;
        bias-pull-up;
    };
};

sdmmc3_b4_sleep_wifi_pins_a: sdmmc3-b4-sleep-wifi-0 {
    pins {
        pinmux = <STM32_PINMUX('F', 0, ANALOG)>, /* SDMMC3_D0 */
             <STM32_PINMUX('F', 4, ANALOG)>, /* SDMMC3_D1 */
             <STM32_PINMUX('D', 5, ANALOG)>, /* SDMMC3_D2 */
             <STM32_PINMUX('D', 7, ANALOG)>, /* SDMMC3_D3 */
             <STM32_PINMUX('G', 15, ANALOG)>, /* SDMMC3_CK */
             <STM32_PINMUX('D', 0, ANALOG)>; /* SDMMC3_CMD */
    };
};

</nowiki></pre>
*RTC节点<br>

AP6236需要使用一个外部输入的32.768Hz的时钟源，因此我们需要使能RTC的外部32.768Hz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stm32mp157c-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>

==实验目的==
熟悉基于Linux操作系统下的WiFi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==
由于WiFi部分与蓝牙部分共用1路RTC时钟，有些操作与蓝牙要修改的内容相同，因此如果之前已经做过了蓝牙的移植，则这些部分不需要再重复修改。<br>

*增加设备树文件<br>

修改arch/arm/dts/stm32mp15xx-fsmp1x.dts文件，在文件末尾添加如下内容：
<pre><nowiki>
&sdmmc3 {
    arm,primecell-periphid = <0x10153180>;
    pinctrl-names = "default", "opendrain", "sleep";
    pinctrl-0 = <&sdmmc3_b4_wifi_pins_a>;
    pinctrl-1 = <&sdmmc3_b4_od_wifi_pins_a>;
    pinctrl-2 = <&sdmmc3_b4_sleep_wifi_pins_a>;
    non-removable;
    st,neg-edge;
    bus-width = <4>;
    vmmc-supply = <&v3v3>;
    mmc-pwrseq = <&wifi_pwrseq>;
    #address-cells = <1>;
    #size-cells = <0>;
    keep-power-in-suspend;
    status = "okay";

    brcmf: bcrmf@1 {
        reg = <1>;
        compatible = "brcm,bcm4329-fmac";
    };
};
</nowiki></pre>
*添加pwrseq管脚配置<br>

修改arch/arm/dts/stm32mp15xx-fsmp1x.dts文件，在根节点末尾下添加如下内容：
<pre><nowiki>
wifi_pwrseq: wifi-pwrseq {
    compatible = "mmc-pwrseq-simple";
    reset-gpios = <&gpiod 4 GPIO_ACTIVE_LOW>;
};
</nowiki></pre>
*开启32.768Hz时钟<br>

如果之前已经做过了蓝牙的移植，则这部分不需要再重复修改。<br>

修改arch/arm/dts/stm32mp15xx-fsmp1x.dts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。如果之前已经做过了蓝牙的移植，则这部分不需要再重复修改。
 #include <dt-bindings/rtc/rtc-stm32.h>
*修改启动选项<br>

在系统中加入了sdmmc3的配置选项，导致系统中eMMC的设备号发生了改变，系统在启动过程中找不到原来的eMMC设备会导致启动失败。我们可以通过修改ubuntu主机中的/tftpboot/pxelinux.cfg/01-00-80-e1-42-60-17文件配置来解决这个问题。
<pre><nowiki>
# Generic Distro Configuration file generated by OpenEmbedded
menu title Select the boot mode
MENU BACKGROUND /splash.bmp
TIMEOUT 20
DEFAULT stm32mp157a-fsmp1a-emmc
LABEL stm32mp157a-fsmp1a-emmc
	KERNEL /uImage
	FDT /stm32mp157a-fsmp1a.dtb
	APPEND root=/dev/mmcblk2p4 rootwait rw console=ttySTM0,115200

LABEL stm32mp157a-fsmp1a-mipi050-emmc
    KERNEL /uImage
	FDT /stm32mp157a-fsmp1a-mipi050.dtb
	APPEND root=/dev/mmcblk2p4 rootwait rw console=ttySTM0,115200

LABEL stm32mp157a-fsmp1a-rgb070-emmc
    KERNEL /uImage
    FDT /stm32mp157a-fsmp1a-rgb070.dtb
    APPEND root=/dev/mmcblk2p4 rootwait rw console=ttySTM0,115200
</nowiki></pre>
* 配置内核<br>

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>
* 编译内核及设备树<br>
 linux@ubuntu:$ make -j4 uImage dtbs LOADADDR=0xC2000040
* 重启测试<br>

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brcmfmac43430-sdio.bin和brcmfmac43430-sdio.st,stm32mp157a-dk1.txt两个固件，如果没有发现这两个文件可从【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>

使用wpa_passphrase工具生成WiFi的配置文件。运行该命令之后需要输入wifi的连接密码。
 root@fsmp1a:# wpa_passphrase "你的WiFi SSID" > wifi.conf
连接WiFi
 root@fsmp1a:# wpa_supplicant -B -c wifi.conf -i wlan0
配置WiFi网络
<pre><nowiki>
root@fsmp1a:# udhcpc -i wlan0
root@fsmp1a:# echo "nameserver 114.114.114.114" > /etc/resolv.conf
root@fsmp1a:# echo "nameserver 8.8.8.8" >> /etc/resolv.conf
root@fsmp1a:# ping -c 4 www.baidu.com
</nowiki></pre>

[[Image:60-1-4-1.png]] <br>