1.  kernel/arch/arm/mach-xxx/Baord-product-xx.c 里面定义了wifi的平台设备 ， static struct platform_device xx_wifi = { .name = "bcm4330_wlan", .id = -1, .dev = { .platform_data = &xx_wifi_control, }, }; 厂商的驱动 是 static struct platform_driver wifi_device = { .probe = wifi_probe, .remove = wifi_remove, .suspend = wifi_suspend, .resume = wifi_resume, .driver = { .name = "bcm4330_wlan", } };首先，厂商的驱动在加载过程中会去 通过GPIO 给wlan芯片 上电.
然后，上面的驱动和设备，他们通过设备模型 match 成功（根据.name字段） 去调用wifi_probe，然后去调用 xx_wifi_set_carddetect
2. xx_wifi_set_carddetect 最中会调用mmc 里面的mmc_rescan, 给host 上电，sdio主要初始化主要工作是在mmc_attach_sdio()中完成, 匹配电压，分配mmc_card数据结构，然后吧该结构add 到bus
3. 经过mmc_rescan后，就有了sdio_funcs （是个device） 在设备模型中了，在wlan driver 的moudle init 时 dhd_module_init() --> dhd_bus_register(), 去注册 sdio_driver bcmsdh_sdmmc_driver, 这过程中，会吧 dhd_sdio {dhdsdio_probe,dhdsdio_disconnect } 注册，当sdio_driver和 sdio_funcs 匹配成功后，会去调用 bcmsdh_sdmmc_probe --> dhdsdio_probe
4.  dhdsdio_probe 会去，new net_device 和attach操作，吧该网络设备和wlan 设备绑定。注意这个时候 因为 dhd_download_fw_on_driverload == false，所以不会去调用 dhd_bus_start()
/* if firmware path present try to download and bring up bus */ if (dhd_download_fw_on_driverload && (ret = dhd_bus_start(bus->dhd)) != 0) { DHD_ERROR(("%s: dhd_bus_start failed ", __FUNCTION__)); if (ret == BCME_NOTUP) goto fail; }


FW 加载过程，
1.start supplicant之前 relaod fw, 通过moudle参数机制,吧fw 路径更新到下面sys 文件
/sys/module/wlan/parameters/fwpath

case CMD_START_SUPPLICANT: try { mNwService.wifiFirmwareReload(mInterfaceName, "STA"); } catch (Exception e) { loge("Failed to reload STA firmware " + e); // continue } try { //A runtime crash can leave the interface up and //this affects connectivity when supplicant starts up. //Ensure interface is down before a supplicant start. mNwService.setInterfaceDown(mInterfaceName); //Set privacy extensions mNwService.setInterfaceIpv6PrivacyExtensions(mInterfaceName, true); } catch (RemoteException re) { loge("Unable to change interface settings: " + re); } catch (IllegalStateException ie) { loge("Unable to change interface settings: " + ie); } mSupConfig.checkSupplicantConf();
2. supplicant开启过程中,会去 open刚刚new的网络设备，最终会调用到dhd_open(), 真正去load fw.  dhdh_open() -> dhd_bus_start() 详细过程 wpa_supplicant_init_iface() --> wpa_drv_init() --> wpa_driver_nl80211_finish_drv_init() --> linux_set_iface_flags() --> ioctl(sock, SIOCSIFFLAGS, &ifr) ...... ...... >
dev_ifsioc() in dev.c  --> __dev_change_flags() --> __dev_open()