[20091123]编译Android操作系统（2）添加USB-Wifi支持

手中zd1211b无线网卡已经可使用wpa_supplicant连接无线网络，

最近的工作主要为修改android的HAL层，使android能够识别该无线网卡。

Android默认使用wifi.c加载无线网卡驱动模块，如果直接编译进内核需要做一定修改。

（1）build/target/board/idea6410/BoardConfig.mk

add

# Wifi related defines

BOARD_WPA_SUPPLICANT_DRIVER := WEXT

（2）external\wpa_supplicant\.config

# CONFIG_NO_WPA=y

CONFIG_OS=unix

CONFIG_IEEE8021X_EAPOL=y

CONFIG_EAP_MD5=y

CONFIG_EAP_MSCHAPV2=y

CONFIG_EAP_TLS=y

CONFIG_EAP_PEAP=y

CONFIG_EAP_TTLS=y

CONFIG_EAP_GTC=y

CONFIG_EAP_OTP=y

CONFIG_EAP_SIM=y

CONFIG_EAP_AKA=y

CONFIG_EAP_PSK=y

CONFIG_EAP_SAKE=y

CONFIG_EAP_GPSK=y

CONFIG_EAP_PAX=y

CONFIG_EAP_LEAP=y

CONFIG_PKCS12=y

CONFIG_SMARTCARD=y

CONFIG_WIRELESS_EXTENSION=y

CONFIG_CTRL_IFACE=y

CONFIG_DRIVER_WEXT=y

（3）hardware/libhardware_legacy/wifi/wifi.c

将驱动直接编译进内核

int wifi_load_driver()

{

    char driver_status[PROPERTY_VALUE_MAX];

    int count = 100; /* wait at most 20 seconds for completion */

LOGE("wifi driver loaded ！");

        return 0;

}

int wifi_unload_driver()

{

    int count = 20; /* wait at most 10 seconds for completion */

LOGE("wifi driver unloaded by rockie!");

return 0;

注意这个定义static const char IFACE_DIR[]           = "/data/system/wpa_supplicant";

（4）编译整个android系统，确认编译完bin目录中含有wpa_supplicant、wpa_cli

（5）修改init.rc文件

add

mkdir /data/misc/wifi 0770 system system

mkdir /data/misc/wifi/sockets 0770 system system

mkdir /data/system/wpa_supplicant 0770 system system

chmod 0660 /data/misc/wifi/wpa_supplicant.conf

add at the end

service wpa_supplicant /system/bin/wpa_supplicant -Dwext -iwlan0 -d -c /data/misc/wifi/wpa_supplicant.conf 

#    user wifi

#    group wifi system

    socket wpa_eth0 dgram 0660 wifi system

    disabled

    oneshot

service dhcpcd /system/bin/dhcpcd -f /system/etc/dhcpcd/dhcpcd.conf -d eth0

    disabled

    oneshot

    

on property:init.svc.wpa_supplicant=stopped

    stop dhcpcd 

（6）添加system/etc/wifi/wpa_supplicant.conf

update_config=1

ctrl_interface=/data/system/wpa_supplicant //这个一定要和IFACE_DIR对应并保证目录权限

eapol_version=1

ap_scan=1

fast_reauth=1

（7）boot and try