1， main 函式的入口：

external/wpa_supplicant_8/wpa_supplicant/main.c

2, init.rc中通過引數指定要載入哪個驅動

3， wpa_supplicant中載入驅動的原理

main.c:  main()

--> wpa_supplicant.c:  wpa_supplicant_add_iface()

--> wpa_supplicant.c:  wpa_supplicant_init_iface()

-->wpa_supplicant.c:   wpa_supplicant_set_driver()

-->wpa_supplicant.c:   select_driver()

-->此處根據driver的索引i, 初始化對應的驅動。 wpa_drivers[i]->global_init.

4. 各個驅動的配置：

在檔案 src/drivers/drivers.c中有所支援全部驅動的一個數組：

struct wpa_driver_ops *wpa_drivers[] =
{
#ifdef CONFIG_DRIVER_WEXT
&wpa_driver_wext_ops,
#endif /* CONFIG_DRIVER_WEXT */
#ifdef CONFIG_DRIVER_NL80211
&wpa_driver_nl80211_ops,
#endif /* CONFIG_DRIVER_NL80211 */
#ifdef CONFIG_DRIVER_HOSTAP
&wpa_driver_hostap_ops,
#endif /* CONFIG_DRIVER_HOSTAP */
#ifdef CONFIG_DRIVER_MADWIFI
&wpa_driver_madwifi_ops,
#endif /* CONFIG_DRIVER_MADWIFI */
#ifdef CONFIG_DRIVER_BSD
&wpa_driver_bsd_ops,
#endif /* CONFIG_DRIVER_BSD */
#ifdef CONFIG_DRIVER_NDIS
&wpa_driver_ndis_ops,
#endif /* CONFIG_DRIVER_NDIS */
#ifdef CONFIG_DRIVER_WIRED
&wpa_driver_wired_ops,
#endif /* CONFIG_DRIVER_WIRED */
#ifdef CONFIG_DRIVER_TEST
&wpa_driver_test_ops,
#endif /* CONFIG_DRIVER_TEST */
#ifdef CONFIG_DRIVER_ROBOSWITCH
&wpa_driver_roboswitch_ops,
#endif /* CONFIG_DRIVER_ROBOSWITCH */
#ifdef CONFIG_DRIVER_ATHEROS
&wpa_driver_atheros_ops,
#endif /* CONFIG_DRIVER_ATHEROS */
#ifdef CONFIG_DRIVER_NONE
&wpa_driver_none_ops,
#endif /* CONFIG_DRIVER_NONE */
NULL
};

各個驅動的具體實現則放在drivers_xxx.c的檔案中。其中wext的實現放在driver_wext.c中。