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wifi详解（三）

發(fā)布時(shí)間：2025/5/22 编程问答 22 豆豆

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1????????WLAN驅(qū)動(dòng)結(jié)構(gòu)介紹

1.1??????SDIO驅(qū)動(dòng)

在drivers/mmc下面是mmc卡，SD卡和SDIO卡驅(qū)動(dòng)部分，其中包括host驅(qū)動(dòng)，card驅(qū)動(dòng)和core部分，由于網(wǎng)絡(luò)接口卡掛接在SDIO總線上，所以在此之前我們先看一下SDIO的驅(qū)動(dòng)結(jié)構(gòu)。其驅(qū)動(dòng)在drivers/mmc目錄下的結(jié)構(gòu)為：

|-- mmc

|?? |-- card

|?? |-- core

|?? |-- host

主要關(guān)注的目錄是core目錄，這個(gè)目錄是真?zhèn)€驅(qū)動(dòng)的核心目錄，是媒體卡的通用代碼部分，包括core.c，host.c和sdio.c等。CORE 層完成了不同協(xié)議和規(guī)范的實(shí)現(xiàn)，并為HOST 層的驅(qū)動(dòng)提供了接口函數(shù)，該目錄完成sdio總線的注冊(cè)操作，相應(yīng)的ops操作，以及支持mmc的代碼。詳細(xì)的情況將在函數(shù)接口部分詳細(xì)討論。

Host目錄是不同平臺(tái)根據(jù)平臺(tái)的特性而編寫的host驅(qū)動(dòng)。

1.2??????Boardcom無線通訊芯片

1.2.1?????? 概述

全球有線和無線通信半導(dǎo)體市場(chǎng)的領(lǐng)導(dǎo)者Broadcom（博通）公司（Nasdaq：BRCM）宣布，推出最新無線組合芯片BCM4330，該芯片可支持更多媒體形式和數(shù)據(jù)應(yīng)用，且不會(huì)增大智能手機(jī)、平板電腦及其他移動(dòng)設(shè)備的尺寸或縮短其電池壽命。BCM4330在單個(gè)芯片上集成了業(yè)界領(lǐng)先的Broadcom 802.11n Wi-Fi、藍(lán)牙和FM無線技術(shù)，與分立式半導(dǎo)體器件組成的解決方案相比，在成本、尺寸、功耗和性能上有顯著優(yōu)勢(shì)，是移動(dòng)設(shè)備的理想選擇。

BCM4330采用了新的Wi-Fi和藍(lán)牙標(biāo)準(zhǔn)，可支持新的、令人振奮的應(yīng)用。例如，Broadcom BCM4330是業(yè)界第一款經(jīng)過藍(lán)牙4.0標(biāo)準(zhǔn)認(rèn)證的組合芯片解決方案，集成了藍(lán)牙低功耗（BLE）標(biāo)準(zhǔn)。該標(biāo)準(zhǔn)使藍(lán)牙技術(shù)能以超低功耗運(yùn)行，因此BCM4330非常適用于需要很長(zhǎng)電池壽命的系統(tǒng)，如無線傳感器、醫(yī)療和健身監(jiān)控設(shè)備等。BCM4330還支持Wi-Fi Direct?和藍(lán)牙高速（HS）標(biāo)準(zhǔn)，因此采用BCM4330的移動(dòng)設(shè)備能直接相互通信，而不必先連接到接入點(diǎn)、成為傳統(tǒng)網(wǎng)絡(luò)的一部分，從而為很多無線設(shè)備之間新的應(yīng)用和使用模式創(chuàng)造了機(jī)會(huì)。

Broadcom一直支持所有主流的操作系統(tǒng)（OS）平臺(tái)，如MicrosoftWindows和Windows Phone、Google Chrome、Android等等，而且不僅是BCM4330，所有藍(lán)牙、WLAN和GPS芯片組都提供這樣的支持。

1.2.2?????? 源碼

Bcm4330驅(qū)動(dòng)源碼一般被廠商單獨(dú)提供，如果要在開發(fā)的LINUX系統(tǒng)中（當(dāng)然它還支持多種平臺(tái)）使用該源碼，可以添加到linux kernel源碼樹里，也可以單獨(dú)組織存放，可以直接編譯到kernel，也可以編譯成模塊，然后再系統(tǒng)啟動(dòng)的流程中或其他適當(dāng)?shù)膶?shí)際加載到kernel中，一般建議單獨(dú)組織并編譯成模塊在需要的時(shí)候加載如kernel。

|-- src

|?? |-- bcmsdio

|?? |-- dhd

|?? |--dongle

|?? |--include

|?? |-- shared

|?? |-- wl

這里主要內(nèi)容到bcmsdio，dhd和wl三個(gè)目錄下，bcm4330驅(qū)動(dòng)的入口在dhd/sys/dhd_linux.c文件中的dhd_module()函數(shù)，設(shè)備的初始化和相關(guān)驅(qū)動(dòng)注冊(cè)都從這里開始，

1.3??????詳細(xì)接口及代碼分析

1.3.1??????WIFI驅(qū)動(dòng)流程分析

??? 以boardcom bcm4329芯片驅(qū)動(dòng)為例，相應(yīng)的函數(shù)流程圖如下：???????

???????????????????????

1.3.2?????? WIFI設(shè)備注冊(cè)流程

Platform_driver_register(wifi_device[_legacy])的調(diào)用將wifi_device[_legacy]驅(qū)動(dòng)注冊(cè)到系統(tǒng)中，wifi_device_legacy是為了兼容老版本的驅(qū)動(dòng)。

Path: wl/sys/wl_android.c

Static struct Platform_driver?wifi_device?={

???????? .probe???? =???? wifi_probe

???????? .remove?? =???? wifi_remove

???????? .suspend? =???? wifi_supend

???????? .resume?? =???? wifi_resume

???????? .driver???? =???? {

???????? .name????? =?????“bcmdhd_wlan”

}

Static struct Platform_driver?wifi_device_legacy?={

???????? .probe???? =???? wifi_probe

???????? .remove?? =???? wifi_remove

???????? .suspend? =???? wifi_supend

???????? .resume?? =???? wifi_resume

???????? .driver???? =???? {

???????? .name????? =?????“bcm4329_wlan”

}

上面的展示了wifi平臺(tái)設(shè)備驅(qū)動(dòng)的注冊(cè)過程，那么在平臺(tái)相關(guān)的代碼區(qū)應(yīng)該有wifi作為平臺(tái)設(shè)備被初始化和注冊(cè)的地方：

Path: kernel/arch/arm/mach-msm/msm_

static struct resource mahimahi_wifi_resources[] = {

??????? [0] = {

??????????????? .name?????????? = "bcm4329_wlan_irq",

??????????????? .start????????? =MSM_GPIO_TO_INT(MAHIMAHI_GPIO_WIFI_IRQ),

??????????????? .end??????????? = MSM_GPIO_TO_INT(MAHIMAHI_GPIO_WIFI_IRQ),

??????????????? .flags????????? = IORESOURCE_IRQ |IORESOURCE_IRQ_HIGHLEVEL | IORESOURCE_IRQ_SHAREABLE,

??????? },

};

static structwifi_platform_data mahimahi_wifi_control = {

????????.set_power????? = mahimahi_wifi_power,

??? ????.set_reset????? = mahimahi_wifi_reset,

????????.set_carddetect = mahimahi_wifi_set_carddetect,

??????? .mem_prealloc?? = mahimahi_wifi_mem_prealloc,

};

static struct platform_device mahimahi_wifi_device = {

????????.name?????????? = "bcm4329_wlan",

????????.id???????????? = 1,

????????.num_resources? = ARRAY_SIZE(mahimahi_wifi_resources),

????????.resource?????? = mahimahi_wifi_resources,

????????.dev??????????? = {

???????????????.platform_data = &mahimahi_wifi_control,

????????},

};

上面是對(duì)wifi_device設(shè)備的初始化，下面是對(duì)該設(shè)備的注冊(cè)：

static int __initmahimahi_wifi_init(void)

{

??????? int ret;

??????? if (!machine_is_mahimahi())

??????????????? return 0;

??????? printk("%s: start\n",__func__);

???????mahimahi_wifi_update_nvs("sd_oobonly=1\r\n", 0);

???????mahimahi_wifi_update_nvs("btc_params70=0x32\r\n", 1);

??????? mahimahi_init_wifi_mem();

????????ret = platform_device_register(&mahimahi_wifi_device);

??????? return ret;

}

late_initcall(mahimahi_wifi_init); ?????//表明在系統(tǒng)啟動(dòng)的后期會(huì)自動(dòng)調(diào)用加載該模塊

這樣，通過上面的初始化和注冊(cè)流程，wifi設(shè)備作為平臺(tái)設(shè)備和驅(qū)動(dòng)就可以握手成功了，這里的平臺(tái)驅(qū)動(dòng)只是對(duì)wifi設(shè)備的簡(jiǎn)單管理，如對(duì)wifi設(shè)備的掛起和恢復(fù)等操作了。但是在wifi設(shè)備初始化之前是不能夠被掛起和恢復(fù)的，那么wifi設(shè)備是如何初始化的呢？

Path: wl/sys/wl_android.c

static int wifi_probe(structplatform_device *pdev)

{

????????struct wifi_platform_data *wifi_ctrl =

????????????????(structwifi_platform_data *)(pdev->dev.platform_data);

??????? DHD_ERROR(("## %s\n",__FUNCTION__));

????????wifi_irqres = platform_get_resource_byname(pdev,IORESOURCE_IRQ, "bcmdhd_wlan_irq");

??????? if (wifi_irqres == NULL)

??????????????? wifi_irqres =platform_get_resource_byname(pdev,

??????????????????????? IORESOURCE_IRQ,"bcm4329_wlan_irq");

????????wifi_control_data = wifi_ctrl;

????????wifi_set_power(1,0);?? /* Power On */

???????wifi_set_carddetect(1); /* CardDetect (0->1) */

??????? up(&wifi_control_sem);

??????? return 0;

}

這是wifi平臺(tái)設(shè)備驅(qū)動(dòng)注冊(cè)時(shí)成功匹配wifi設(shè)備后調(diào)用的函數(shù)wifi_probe()，它的主要工作就是從wifi設(shè)備中獲取終端資源，并獲取wifi_platform_data類型結(jié)構(gòu)賦予wifi_control_data變量，這一步很重要，下面就可以看出了它的重要性。然后調(diào)用wifi_set_power和wifi_set_carddetect函數(shù)給wifi芯片上電并檢測(cè)。

int wifi_set_power(int on, unsignedlong msec)

{

??????? DHD_ERROR(("%s = %d\n",__FUNCTION__, on));

??????? if (wifi_control_data &&wifi_control_data->set_power) {

????????????????wifi_control_data->set_power(on);

??????? }

??????? if (msec)

??????????????? msleep(msec);

??????? return 0;

}

Wifi_set_power函數(shù)中調(diào)用wifi_control_data->set_power(on)，wifi_control_data就是剛才說的那個(gè)重要變量，注意它是從wifi_device平臺(tái)設(shè)備的wifi_platform_data獲取的，那么看看上面的wifi_device初始化的代碼：

static struct platform_device mahimahi_wifi_device = {

??????? .name?????????? = "bcm4329_wlan",

??????? .id???????????? = 1,

??????? .num_resources? = ARRAY_SIZE(mahimahi_wifi_resources),

??????? .resource?????? = mahimahi_wifi_resources,

??????? .dev??????????? = {

??????????????? .platform_data =&mahimahi_wifi_control,

??????? },

};

static struct wifi_platform_datamahimahi_wifi_control= {

??????? .set_power????? =?mahimahi_wifi_power,

??????? .set_reset????? = mahimahi_wifi_reset,

??????? .set_carddetect =?mahimahi_wifi_set_carddetect,

??????? .mem_prealloc?? = mahimahi_wifi_mem_prealloc,

};

所以它實(shí)際調(diào)用的是mahimahi_wifi_power函數(shù)，該函數(shù)的定義在kernel/arch/arm /mach-msm/board-mahimahi-mmc.c之中：

int mahimahi_wifi_power(int on)

{

???????printk("%s: %d\n", __func__, on);

??????? if (on) {

???????????????config_gpio_table(wifi_on_gpio_table,

?????????????????? ???????????????ARRAY_SIZE(wifi_on_gpio_table));

???????????????mdelay(50);

??????? } else {

???????????????config_gpio_table(wifi_off_gpio_table,

?????????????????????????????????ARRAY_SIZE(wifi_off_gpio_table));

??????? }

??????? mdelay(100);

??????? gpio_set_value(MAHIMAHI_GPIO_WIFI_SHUTDOWN_N,on); /* WIFI_SHUTDOWN */

??????? mdelay(200);

???????mahimahi_wifi_power_state = on;

??????? return 0;

}

調(diào)用gpio_set_value操作wifi芯片，給wifi芯片上電。那么來看看wifi_set_ carddetect函數(shù)究竟干了什么：

Path：wl/sys/wl_android.c

static int wifi_set_carddetect(int on)

{

???????DHD_ERROR(("%s = %d\n", __FUNCTION__, on));

??????? if(wifi_control_data && wifi_control_data->set_carddetect) {

???????????????wifi_control_data->set_carddetect(on);

??????? }

??????? return 0;

}

同樣會(huì)調(diào)用wifi_device的mahimahi_wifi_set_carddetect函數(shù)：

Path:kernel/arch/arm/mach-msm/board-mahimahi-mmc.c

int mahimahi_wifi_set_carddetect(int val)

{

???????pr_info("%s: %d\n", __func__, val);

???????mahimahi_wifi_cd = val;

??????? if(wifi_status_cb) {

????????????????wifi_status_cb(val,wifi_status_cb_devid);

??????? } else

???????????????pr_warning("%s: Nobody to notify\n", __func__);

??????? return 0;

}

Wifi_status_cb代碼：

static int mahimahi_wifi_status_register(

??????????????????????? void (*callback)(intcard_present, void *dev_id),

??????????????????????? void *dev_id)

{

??????? if (wifi_status_cb)

??????????????? return -EAGAIN;

????????wifi_status_cb = callback;

?? ?????wifi_status_cb_devid = dev_id;

??????? return 0;

}

static unsigned intmahimahi_wifi_status(struct device *dev)

{

??????? return mahimahi_wifi_cd;

}

static structmmc_platform_data mahimahi_wifi_data = {

??????? .ocr_mask?????????????? = MMC_VDD_28_29,

??????? .built_in?????????????? = 1,

??????? .status???????????????? = mahimahi_wifi_status,

????????.register_status_notify= mahimahi_wifi_status_register,

??????? .embedded_sdio????????? = &mahimahi_wifi_emb_data,

};

由上面代碼；不難看出會(huì)有個(gè)地方調(diào)用mahimahi_wifi_status_register設(shè)置wifi_status_cb這個(gè)回調(diào)函數(shù)，可以跟蹤這個(gè)mahimahi_wifi_data結(jié)構(gòu)體，來看看它被傳遞給了誰：

int msm_add_sdcc(unsigned intcontroller, struct mmc_platform_data *plat,

???????????????? unsigned int stat_irq,unsigned long stat_irq_flags);

int __initmahimahi_init_mmc(unsigned int sys_rev, unsigned debug_uart)

{

??????? ……

????????msm_add_sdcc(1, &mahimahi_wifi_data, 0, 0);

?????? ……

??????? if (system_rev > 0)

??????????????? msm_add_sdcc(2,&mahimahi_sdslot_data, 0, 0);

??????? else {

?? ?????????????mahimahi_sdslot_data.status =mahimahi_sdslot_status_rev0;

???????????????mahimahi_sdslot_data.register_status_notify = NULL;

???????????????set_irq_wake(MSM_GPIO_TO_INT(MAHIMAHI_GPIO_SDMC_CD_REV0_N), 1);

????????????????msm_add_sdcc(2, &mahimahi_sdslot_data,

???????? ……

}

可以跟蹤到這里Path：kernel/arch/arm/mach-msm/devices-msm7x30.c

struct platform_device msm_device_sdc1 = {

????????.name?????????? = "msm_sdcc",

????????.id???????????? = 1,

????????.num_resources? = ARRAY_SIZE(resources_sdc1),

????????.resource?????? = resources_sdc1,

????????.dev??????????? = {

???????????????.coherent_dma_mask????? =0xffffffff,

????????},

};

struct platform_device msm_device_sdc2 = {

????????.name?????????? = "msm_sdcc",

????????.id???????????? = 2,

????????.num_resources? = ARRAY_SIZE(resources_sdc2),

????????.resource?????? = resources_sdc2,

????????.dev??????????? = {

???????????????.coherent_dma_mask????? =0xffffffff,

????????},

};

struct platform_devicemsm_device_sdc3 = {

??????? .name?????????? = "msm_sdcc",

??????? .id???????????? = 3,

??????? .num_resources? = ARRAY_SIZE(resources_sdc3),

??????? .resource?????? = resources_sdc3,

??????? .dev??????????? = {

??????????????? .coherent_dma_mask????? = 0xffffffff,

??????? },

};

struct platform_device msm_device_sdc4= {

??????? .name?????????? = "msm_sdcc",

??????? .id???????????? = 4,

??????? .num_resources? = ARRAY_SIZE(resources_sdc4),

??????? .resource?????? = resources_sdc4,

??????? .dev??????????? = {

?????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????439,2-16????? 62%

??????????????? .coherent_dma_mask????? = 0xffffffff,

??????? },

};

static struct platform_device *msm_sdcc_devices[] __initdata = {

??????? &msm_device_sdc1,

???? ???&msm_device_sdc2,

??????? &msm_device_sdc3,

??????? &msm_device_sdc4,

};

int __initmsm_add_sdcc(unsigned int controller, struct mmc_platform_data *plat,

??????????????????????? unsigned int stat_irq,unsigned long stat_irq_flags)

{

??????? ……

?????? ?pdev =msm_sdcc_devices[controller-1]; //因?yàn)閭鬟^來的controller是1，所以下面注冊(cè)的是第一個(gè)平臺(tái)設(shè)備

????????pdev->dev.platform_data= plat;??//被傳遞給平臺(tái)設(shè)備的platform_data

??????? res =platform_get_resource_byname(pdev, IORESOURCE_IRQ, "status_irq");

??????? if (!res)

?????????????? ?return -EINVAL;

??????? else if (stat_irq) {

??????????????? res->start = res->end =stat_irq;

??????????????? res->flags &=~IORESOURCE_DISABLED;

??????????????? res->flags |=stat_irq_flags;

??????? }

????????return platform_device_register(pdev); //如上所述

}

那么這個(gè)平臺(tái)設(shè)備是什么呢，就是sd卡控制器，也就是前面說的host驅(qū)動(dòng)所驅(qū)動(dòng)的主機(jī)控制設(shè)備。

Path: drivers/mmc/host/msm_sdcc.c

static struct platform_drivermsmsdcc_driver = {

??????? .probe????????? =?msmsdcc_probe,

??????? .suspend??????? = msmsdcc_suspend,

??????? .resume???????? = msmsdcc_resume,

??????? .driver???????? = {

??????????????? .name?? =?"msm_sdcc",

??????? },

};

static int __initmsmsdcc_init(void)

{

????????return platform_driver_register(&msmsdcc_driver);

}

驅(qū)動(dòng)成功匹配設(shè)備后，調(diào)用probe函數(shù)：

static int

msmsdcc_probe(structplatform_device *pdev)

{

......

if (stat_irqres &&!(stat_irqres->flags & IORESOURCE_DISABLED)) {

……

??????? } else if(plat->register_status_notify) {

????????????????plat->register_status_notify(msmsdcc_status_notify_cb,host);

??????? } else if (!plat->status)

......

}

msmsdcc_status_notify_cb調(diào)用msmsdcc_check_status函數(shù)：

msmsdcc_status_notify_cb(intcard_present, void *dev_id)

{

??????? struct msmsdcc_host *host = dev_id;

??????? printk(KERN_DEBUG "%s:card_present %d\n", mmc_hostname(host->mmc),

?????????????? card_present);

????????msmsdcc_check_status((unsigned long) host);

}

msmsdcc_check_status調(diào)用mmc_detect_change函數(shù)：

static void

msmsdcc_check_status(unsignedlong data)

{

??????? ……

??????? if (status ^ host->oldstat) {

??????????????? pr_info("%s: Slot statuschange detected (%d -> %d)\n",

?? ?????????????????????mmc_hostname(host->mmc),host->oldstat, status);

??????????????? if (status &&!host->plat->built_in)

????????????????????????mmc_detect_change(host->mmc, (5 * HZ) / 2);

??????????????? else

????????????????????????mmc_detect_change(host->mmc, 0);

??????? }

??????? host->oldstat = status;

out:

??????? if (host->timer.function)

??????????????? mod_timer(&host->timer,jiffies + HZ);

}

可以看到mmc_detect_change被調(diào)用了，這個(gè)函數(shù)觸發(fā)了一個(gè)延時(shí)工作：

void mmc_detect_change(structmmc_host *host, unsigned long delay)

{

……

????????mmc_schedule_delayed_work(&host->detect, delay);

}

這個(gè)時(shí)候它會(huì)在delay時(shí)間后，執(zhí)行host->detect延時(shí)工作對(duì)應(yīng)的函數(shù)，在host驅(qū)動(dòng)注冊(cè)并匹配設(shè)備成功后執(zhí)行的probe函數(shù)里，會(huì)調(diào)用mmc_alloc_host動(dòng)態(tài)創(chuàng)建一個(gè)mmc_host：

msmsdcc_probe(structplatform_device *pdev)

{

......

???????? * Setup our host structure

???????? */

????????mmc = mmc_alloc_host(sizeof(struct msmsdcc_host),&pdev->dev);

??????? if (!mmc) {

??????????????? ret = -ENOMEM;

????????? ??????goto out;

??????? }

......

}

mmc_alloc_host初始化工作入口：

struct mmc_host*mmc_alloc_host(int extra, struct device *dev)

{

......

INIT_DELAYED_WORK(&host->detect, mmc_rescan);

......

}

mmc_rescan是core.c中一個(gè)很重要的函數(shù)，它遵照 SDIO 卡協(xié)議的 SDIO 卡啟動(dòng)過程，包括了非激活模式、卡識(shí)別模式和數(shù)據(jù)傳輸模式三種模式共九種狀態(tài)的轉(zhuǎn)換，你需要參照相關(guān)規(guī)范來理解。

void mmc_rescan(structwork_struct *work)

{

??????? struct mmc_host *host =

??????????????? container_of(work, structmmc_host, detect.work);

......

?????? ?mmc_power_up(host);

????????sdio_reset(host);

????????mmc_go_idle(host);

???????mmc_send_if_cond(host, host->ocr_avail);

??????? /*

???????? * First we search for SDIO...

???????? */

????????err = mmc_send_io_op_cond(host, 0, &ocr);

??????? if (!err) {

????????????????if (mmc_attach_sdio(host, ocr))

????????????????????? ??mmc_power_off(host);

??????????????? extend_wakelock = 1;

??????????????? goto out;

??????? }

......

}

這個(gè)mmc_attach_sdio函數(shù)很重要，它是SDIO卡的初始化的起點(diǎn)，主要工作包括：匹配SDIO卡的工作電壓，分配并初始化mmc_card結(jié)構(gòu)，然后注冊(cè)mmc_card到系統(tǒng)中：

?* Starting point for SDIO card init.

?*/

int mmc_attach_sdio(structmmc_host *host, u32 ocr)

{

??????? ……

????????mmc_attach_bus(host,&mmc_sdio_ops);? //初始化host的bus_ops

?????? ……

????????host->ocr = mmc_select_voltage(host, ocr);?//匹配SDIO卡工作電壓

??????? ……

??????? /*

???????? * Detect and init the card.

???????? */

????????err = mmc_sdio_init_card(host, host->ocr, NULL, 0);//檢測(cè)，分配初始化mmc_card

??????? if (err)

??????????????? goto err;

??????? card = host->card;

???????? * If needed, disconnect card detectionpull-up resistor.

???????? */

??????? err = sdio_disable_cd(card);

??????? if (err)

??????????????? goto remove;

??????? /*

???????? *?Initialize (but don't add) all present functions.

???????? */

????????for (i = 0; i < funcs; i++, card->sdio_funcs++) {

#ifdef CONFIG_MMC_EMBEDDED_SDIO

????????????????if(host->embedded_sdio_data.funcs) {

???????????????????????struct sdio_func *tmp;

????????????????????????tmp = sdio_alloc_func(host->card);

????????????????????????if(IS_ERR(tmp))

???????????????????????????????goto remove;

???????????????????????tmp->num = (i + 1);

???????????????????????card->sdio_func[i] = tmp;

???????????????????????tmp->class = host->embedded_sdio_data.funcs[i].f_class;

???????????????????????tmp->max_blksize = host->embedded_sdio_data.funcs[i].f_maxblksize;

???????????????????????tmp->vendor = card->cis.vendor;

???????????????????????tmp->device = card->cis.device;

????????????????} else {

#endif

??????????????????????? err =sdio_init_func(host->card, i + 1);

??????????????????????? if (err)

??????????????????????????????? goto remove;

#ifdefCONFIG_MMC_EMBEDDED_SDIO

??????????????? }

#endif

??????? }

??????? mmc_release_host(host);

??????? /*

???????? * First add the card to the drivermodel...

???????? */

????????err = mmc_add_card(host->card);? ?? //添加mmc_card

??????? if (err)

??????????????? goto remove_added;

??????? /*

???????? * ...then the SDIO functions.

???????? */

??????? for (i = 0;i < funcs;i++) {

????????????????err =sdio_add_func(host->card->sdio_func[i]);??????????????//將sdio_func加入系統(tǒng)

?????????? ?????if (err)

?????????????????????? goto remove_added;

??????? }

??????? return 0;

......

}

這樣，SDIO卡已經(jīng)初始化成功并添加到了驅(qū)動(dòng)中。上面說的過程是在SDIO設(shè)備注冊(cè)時(shí)的調(diào)用流程，mmc_rescan是整個(gè)流程主體部分，由它來完成SDIO設(shè)備的初始化和添加。其實(shí)上面的流程只是創(chuàng)建，初始化，添加SDIO設(shè)備的一條線，還有另外的兩條線也會(huì)調(diào)用mmc_rescan函數(shù)進(jìn)行SDIO設(shè)備的上述操作：

（1）??? 加載SDIO host驅(qū)動(dòng)模塊

（2）??? SDIO設(shè)備中斷

1.3.2.1????????加載SDIO host驅(qū)動(dòng)模塊

Host作為平臺(tái)設(shè)備被注冊(cè)，前面也有列出相應(yīng)源碼：

static struct platform_drivermsmsdcc_driver = {

??????? .probe????????? =?msmsdcc_probe,

??????? .suspend??????? = msmsdcc_suspend,

??????? .resume???????? = msmsdcc_resume,

??????? .driver?????? ??= {

??????????????? .name?? = "msm_sdcc",

??????? },

};

static int __initmsmsdcc_init(void)

{

????????returnplatform_driver_register(&msmsdcc_driver);

}

Probe函數(shù)會(huì)調(diào)用mmc_alloc_host函數(shù)（代碼前面已經(jīng)貼出）來創(chuàng)建mmc_host結(jié)構(gòu)變量，進(jìn)行必要的初始化之后，調(diào)用mmc_add_host函數(shù)將它添加到驅(qū)動(dòng)里面：

int mmc_add_host(structmmc_host *host)

{

??????? ……

??????? err =device_add(&host->class_dev);

??????? if (err)

??????????????? return err;

????????mmc_start_host(host);

??????? if (!(host->pm_flags &MMC_PM_IGNORE_PM_NOTIFY))

??????????????? register_pm_notifier(&host->pm_notify);

??????? return 0;

}

???????Mmc_start_host定義如下：

void mmc_start_host(structmmc_host *host)

{

??????mmc_power_off(host);

?????? mmc_detect_change(host, 0);

}

mmc_power_off中對(duì)?ios進(jìn)行了設(shè)置，然后調(diào)用?mmc_set_ios(host);

host->ios.power_mode = MMC_POWER_OFF;

?????? host->ios.bus_width = MMC_BUS_WIDTH_1;

?????? host->ios.timing =MMC_TIMING_LEGACY;

?????? mmc_set_ios(host);

mmc_set_ios(host) 中的關(guān)鍵語句 host->ops->set_ios(host, ios)，實(shí)際上在host驅(qū)動(dòng)的probe函數(shù)中就已經(jīng)對(duì)host->ops進(jìn)行了初始化：

……

???????? * Setup MMC host structure

???????? */

????????mmc->ops = &msmsdcc_ops;

……

static const structmmc_host_ops msmsdcc_ops = {

??????? .request??????? = msmsdcc_request,

??????? .set_ios??????? =msmsdcc_set_ios,

??????? .enable_sdio_irq =msmsdcc_enable_sdio_irq,

};

所以實(shí)際上調(diào)用的是msmsdcc_set_ios，關(guān)于這個(gè)函數(shù)就不介紹了，可以參考源碼，再看 mmc_detect_change(host, 0)，最后一句是：

??????mmc_schedule_delayed_work(&host->detect,delay);

實(shí)際上就是調(diào)用我們前面說的延時(shí)函數(shù) mmc_rescan，后面的流程是一樣的。

1.3.2.2????????SDIO設(shè)備中斷

SDIO設(shè)備通過SDIO總線與host相連，SDIO總線的DAT[1]即pin8可以作為中斷線使用，當(dāng)SDIO設(shè)備向host產(chǎn)生中斷時(shí)，host會(huì)對(duì)終端做出相應(yīng)的動(dòng)作，在host驅(qū)動(dòng)的probe函數(shù)中申請(qǐng)并注冊(cè)相應(yīng)的中斷函數(shù)：

static int

msmsdcc_probe(structplatform_device *pdev)

{

......

? cmd_irqres = platform_get_resource_byname(pdev, IORESOURCE_IRQ,

?????????????????????????????????????????????????"cmd_irq");

??????? pio_irqres =platform_get_resource_byname(pdev, IORESOURCE_IRQ,

?????????????????????????????????????????????????"pio_irq");

????????stat_irqres =platform_get_resource_byname(pdev, IORESOURCE_IRQ,

??????????????????????????????????????????????????"status_irq");

......

? if (stat_irqres && !(stat_irqres->flags &IORESOURCE_DISABLED)) {

??????????????? unsigned long irqflags =IRQF_SHARED |

??????????????????????? (stat_irqres->flags& IRQF_TRIGGER_MASK);

????????????????host->stat_irq = stat_irqres->start;

????????????????ret = request_irq(host->stat_irq,

??????????????????????????????????msmsdcc_platform_status_irq,

?????????????????????????????????irqflags,

?????????????????????????????????DRIVER_NAME " (slot)",

?????????????????????????????????host);

??????????????? if (ret) {

??????????????????????? pr_err("%s: Unableto get slot IRQ %d (%d)\n",

??????????????????????????????mmc_hostname(mmc), host->stat_irq, ret);

??????????????????????? goto clk_disable;

??????????????? }

??????? }

......

}

當(dāng)產(chǎn)生相應(yīng)的中斷時(shí)調(diào)用msmsdcc_platform_status_irq中斷處理函數(shù)，這個(gè)函數(shù)的處理流程：

msmsdcc_platform_status_irq—>

msmsdcc_check_statusà

mmc_detect_changeà

mmc_rescanà

那么，這里為何調(diào)用mmc_rescan呢？因?yàn)榍懊嬲f過mmc_rescanrescan函數(shù)主要用于SDIO設(shè)備的初始化，如果SDIO設(shè)備產(chǎn)生中斷不應(yīng)該是已經(jīng)初始化可以使用了嗎？其實(shí)mmc_rescan還有其它的工作，從函數(shù)名就能看出來它還有再掃描檢測(cè)功能，即如果設(shè)備產(chǎn)生了中斷，mmc_rescan函數(shù)一開始就會(huì)再次檢測(cè)所有掛接在該host上的所有SDIO設(shè)備，確認(rèn)是否存在，如果不存在就做相應(yīng)的釋放工作，以確保數(shù)據(jù)的一致性。如果檢測(cè)到了新的設(shè)備那么它就會(huì)創(chuàng)建一個(gè)新的mmc_card，初始化并添加該設(shè)備。

中斷引發(fā)的調(diào)用mmc_rescan動(dòng)作的意義：實(shí)現(xiàn)了SDIO設(shè)備的熱插拔功能。

1.3.3?????? WIFI驅(qū)動(dòng)流程（二）

? 此調(diào)用流程由dhd_bus_register發(fā)起，通過sdio_register_driver注冊(cè)一個(gè)sdio設(shè)備驅(qū)動(dòng)，然后通過dhdsdio_probe初始化并注冊(cè)一個(gè)網(wǎng)絡(luò)設(shè)備，網(wǎng)絡(luò)設(shè)備的注冊(cè)標(biāo)志著wifi驅(qū)動(dòng)已經(jīng)成功加載，關(guān)于網(wǎng)絡(luò)設(shè)備的創(chuàng)建，初始化和注冊(cè)后面會(huì)有詳細(xì)介紹，先來理一下上面的調(diào)用流程，：

dhd_mudule_init—>???????????? //path:dhd/sys/dhd_linux.c

Dhd_bus_registerà??????? // dhd/sys/dhd_sdio.c

Bcmsdh_registerà???????? // bcmsdio/sys/bcmsdh_linux.c

Sdio_function_inità????????????? // bcmsdio/sys/bcmsdh_sdmmc_linux.c

Sdio_register_driverà? // bcmsdio/sys/bcmsdh_sdmmc_linux.c

Bcmsdh_sdmmc_probeà//bcmsdio/sys/bcmsdh_sdmmc_linux.c

Bcmsdh_probeà//bcmsdio/sys/bcmsdh_linux.c

Bcmsdio_probeà //dhd/sys/dhd_sdio.c

這里注意上面兩個(gè)紅色標(biāo)記的函數(shù)，sdio_register_driver注冊(cè)了一個(gè)sdio設(shè)備，在匹配成功后調(diào)用bcmsdh_sdmmc_probe函數(shù)，這個(gè)函數(shù)會(huì)調(diào)用bcmsdh_probe。這里有一點(diǎn)要注意：瀏覽bcmsdh_linux.c文件可以看出，在bcmsdh_register函數(shù)中，當(dāng)定義了BCMLXSDMMC宏時(shí)，會(huì)調(diào)用sdio_function_init函數(shù)，否則調(diào)用driver_register函數(shù)：

int

bcmsdh_register(bcmsdh_driver_t*driver)

{

??????? int error = 0;

????????drvinfo = *driver; //注意這里，后面會(huì)介紹到它的用處

#if defined(BCMPLATFORM_BUS)

#if defined(BCMLXSDMMC)

???????SDLX_MSG(("Linux Kernel SDIO/MMC Driver\n"));

????????error =sdio_function_init();

#else

???????SDLX_MSG(("Intel PXA270 SDIO Driver\n"));

????????error =driver_register(&bcmsdh_driver);

#endif /* defined(BCMLXSDMMC) */

??????? return error;

#endif /*defined(BCMPLATFORM_BUS) */

#if !defined(BCMPLATFORM_BUS)&& !defined(BCMLXSDMMC)

#if (LINUX_VERSION_CODE <KERNEL_VERSION(2, 6, 0))

??????? if (!(error =pci_module_init(&bcmsdh_pci_driver)))

?? ?????????????return 0;

#else

??????? if (!(error =pci_register_driver(&bcmsdh_pci_driver)))

??????????????? return 0;

#endif

??????? SDLX_MSG(("%s: pci_module_initfailed 0x%x\n", __FUNCTION__, error));

#endif /* BCMPLATFORM_BUS */

??????? return error;

}

上面的流程中有sdio_function_init的調(diào)用出現(xiàn)，所以這里實(shí)際上BCMLXSDMMC宏被定義了，bcmsdh_probe函數(shù)只是作為一個(gè)普通函數(shù)被調(diào)用，如果不定義該宏，那么bcmsdh_probe函數(shù)會(huì)被作為驅(qū)動(dòng)匹配設(shè)備后第一個(gè)調(diào)用的函數(shù)而被自動(dòng)調(diào)用。

再看看dhdsdio_probe函數(shù)調(diào)用的玄機(jī)，從上面的bcmsdh_register函數(shù)可以看出它的參數(shù)被傳遞給了drvinfo，看看bcmsdh_register的調(diào)用地方：

static bcmsdh_driver_t dhd_sdio = {

????????dhdsdio_probe,

????????dhdsdio_disconnect

};

int

dhd_bus_register(void)

{

??????? DHD_TRACE(("%s: Enter\n",__FUNCTION__));

??????? return?bcmsdh_register(&dhd_sdio);

}

上面?zhèn)鬟f的參數(shù)是dhd_sdio結(jié)構(gòu)變量，被用兩個(gè)函數(shù)初始化了，那么哪一個(gè)是attach呢？需要找到定義bcmsdh_driver_t結(jié)構(gòu)定義的地方：

Path：src/include/bcmsdh.h

/* callback functions */

typedef struct {

??????? /* attach to device */

????????void *(*attach)(uint16 vend_id, uint16 dev_id, uint16 bus,uint16 slot,

???????????????????????uint16 func, uint bustype, void * regsva, osl_t * osh,

???????????????????????void * param);

??????? /* detach from device */

??????? void (*detach)(void *ch);

} bcmsdh_driver_t;

沒錯(cuò)，就是第一個(gè)dhdsdio_probe函數(shù)，再來看看什么地方調(diào)用了這個(gè)attach函數(shù)：

Path:bcmsdio/sys/bcmsdh_linux.c

#ifndef BCMLXSDMMC

static

#endif /* BCMLXSDMMC */

int bcmsdh_probe(struct device*dev)

{

......

if (!(sdhc->ch =?drvinfo.attach((vendevid>> 16),

????????????????????????????????????????(vendevid & 0xFFFF), 0, 0, 0, 0,

??????????????????????????????????????? (void*)regs, NULL, sdh))) {

???????????? ???SDLX_MSG(("%s: device attachfailed\n", __FUNCTION__));

??????????????? goto err;

??????? }

??????? return 0;

......

}

紅色部分的函數(shù)調(diào)用是drvinfo.attach，就是上面?zhèn)鬟f過來的dhdsdio_probe函數(shù)了，仔細(xì)閱讀你會(huì)發(fā)現(xiàn)上面那個(gè)bcmsdh_driver_t結(jié)構(gòu)體定義的地方有個(gè)說明，即把該結(jié)構(gòu)的成員函數(shù)當(dāng)做callback函數(shù)來使用，這就是它的用意所在。

1.3.4?????? 網(wǎng)絡(luò)設(shè)備注冊(cè)流程

上面是網(wǎng)絡(luò)設(shè)備注冊(cè)流程，在dhdsdio_probe函數(shù)中先后對(duì)dhd_attach和dhd_net_attach兩個(gè)函數(shù)調(diào)用，dhd_attach主要用于創(chuàng)建和初始化dhd_info_t和net_device兩個(gè)結(jié)構(gòu)變量，然后調(diào)用dhd_add_if將創(chuàng)建的net_device變量添加到dhd_info_t變量的iflist列表中（支持多接口）。

Dhd_attach的流程如下：

dhd_pub_t *

dhd_attach(osl_t *osh, structdhd_bus *bus, uint bus_hdrlen)

{

??????? dhd_info_t *dhd = NULL;

??????? struct net_device *net = NULL;

......

??????? /* Allocate etherdev, including spacefor private structure */

????????if (!(net = alloc_etherdev(sizeof(dhd)))) {???//網(wǎng)絡(luò)設(shè)備的創(chuàng)建

??????????????? DHD_ERROR(("%s: OOM -alloc_etherdev\n", __FUNCTION__));

??????????????? goto fail;

??????? }

??????? dhd_state |=DHD_ATTACH_STATE_NET_ALLOC;

??????? /* Allocate primary dhd_info */

????????if (!(dhd = MALLOC(osh, sizeof(dhd_info_t)))) { //dhd的創(chuàng)建

??????????????? DHD_ERROR(("%s: OOM -alloc dhd_info\n", __FUNCTION__));

??????????????? goto fail;

??????? }

......

/* Set network interface name if it was provided as moduleparameter */

??????? if (iface_name[0]) {

??????????????? int len;

??????????????? char ch;

??????????????? strncpy(net->name,iface_name, IFNAMSIZ);

??????????????? net->name[IFNAMSIZ - 1] = 0;

??????????????? len = strlen(net->name);

??????????????? ch = net->name[len - 1];

??????????????? if ((ch > '9' || ch <'0') && (len < IFNAMSIZ - 2))

??????????????????????? strcat(net->name,"%d");

??????? }

????????if (dhd_add_if(dhd, 0, (void *)net, net->name, NULL, 0, 0)== DHD_BAD_IF)???//將前面創(chuàng)建的net添加到iflist列表中

??????????????? goto fail;

??????? dhd_state |= DHD_ATTACH_STATE_ADD_IF;

......

Memcpy(netdev_priv(net), &dhd, sizeof(dhd));?//關(guān)聯(lián)dhd和net

//dhd的初始化工作

}

Dhd_add_if的添加網(wǎng)絡(luò)接口流程：

int

dhd_add_if(dhd_info_t *dhd, int ifidx, void *handle, char *name,

????????uint8 *mac_addr,uint32 flags, uint8 bssidx)

{

??????? dhd_if_t *ifp;

??????? DHD_TRACE(("%s: idx %d,handle->%p\n", __FUNCTION__, ifidx, handle));

??????? ASSERT(dhd && (ifidx <DHD_MAX_IFS));

????????ifp =dhd->iflist[ifidx];

??????? if (ifp != NULL) {

??????????????? if (ifp->net != NULL) {

???????????????????????netif_stop_queue(ifp->net);

???????????????????????unregister_netdev(ifp->net);

????????????????????????free_netdev(ifp->net);?? //如果已經(jīng)存在，釋放net成員

??????????????? }

??????? } else

????????????????if ((ifp = MALLOC(dhd->pub.osh,sizeof(dhd_if_t))) == NULL) {

???????????????????????DHD_ERROR(("%s: OOM - dhd_if_t\n", __FUNCTION__)); ???? //否則，創(chuàng)建一個(gè)dhd_if_t結(jié)構(gòu)變量

??????????????????????? return -ENOMEM;

??????????????? }

??????? memset(ifp, 0, sizeof(dhd_if_t));

????????ifp->info = dhd;??????//進(jìn)行系列初始化，添加工作

???????dhd->iflist[ifidx] = ifp;

???????strncpy(ifp->name, name, IFNAMSIZ);

??????? ifp->name[IFNAMSIZ] = '\0';

??????? if (mac_addr != NULL)

????????????????memcpy(&ifp->mac_addr, mac_addr,ETHER_ADDR_LEN);

??????? if (handle == NULL) {

??????????????? ifp->state = DHD_IF_ADD;

??????????????? ifp->idx = ifidx;

??????????????? ifp->bssidx = bssidx;

???????????????ASSERT(&dhd->thr_sysioc_ctl.thr_pid >= 0);

???????????????up(&dhd->thr_sysioc_ctl.sema);

??????? } else

????????????????ifp->net = (struct net_device *)handle;?????????????//handle即一個(gè)net_device變量

??????? return 0;

}

這樣，一個(gè)net_device網(wǎng)路設(shè)備就被添加到了接口管理列表中了，但是這是網(wǎng)路設(shè)備還沒有完成初始化和注冊(cè)工作，bcmsdio_probe函數(shù)隨后對(duì)dhd_net_attach的調(diào)用完成了這個(gè)操作：

int

dhd_net_attach(dhd_pub_t*dhdp, int ifidx)

{

??????? dhd_info_t *dhd = (dhd_info_t*)dhdp->info;

??????? struct net_device *net = NULL;

??????? int err = 0;

??????? uint8 temp_addr[ETHER_ADDR_LEN] = {0x00, 0x90, 0x4c, 0x11, 0x22, 0x33 };

??????? DHD_TRACE(("%s: ifidx %d\n",__FUNCTION__, ifidx));

??????? ASSERT(dhd &&dhd->iflist[ifidx]);

????????net = dhd->iflist[ifidx]->net;??????????????//首先從剛才添加的接口列表中取出net，然后進(jìn)行下面的系列初始化工作

??????? ASSERT(net);

//根據(jù)內(nèi)核版本信息，選擇對(duì)net成員函數(shù)的初始化方式，假設(shè)是2.6.30的版本

#if (LINUX_VERSION_CODE <KERNEL_VERSION(2, 6, 31))

??????? ASSERT(!net->open);

????????net->get_stats = dhd_get_stats;

????????net->do_ioctl =dhd_ioctl_entry;

???????net->hard_start_xmit = dhd_start_xmit;

???????net->set_mac_address = dhd_set_mac_address;

???????net->set_multicast_list = dhd_set_multicast_list;

????????net->open =net->stop = NULL;

#else

??????? ASSERT(!net->netdev_ops);

??????? net->netdev_ops = &dhd_ops_virt;

#endif

??????? /* Ok, link into the network layer...*/

??????? if (ifidx == 0) {

??????????????? /*

???????????????? * device functions for theprimary interface only

???????????????? */

#if (LINUX_VERSION_CODE <KERNEL_VERSION(2, 6, 31))

????????????????net->open = dhd_open;

???????????????net->stop = dhd_stop;

#else

??????????? ????net->netdev_ops = &dhd_ops_pri;

#endif

??????? } else {

??????????????? /*

???????????????? * We have to use the primaryMAC for virtual interfaces

??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????3417,1-8????? 66%

???????????????? */

??????????????? memcpy(temp_addr,dhd->iflist[ifidx]->mac_addr, ETHER_ADDR_LEN);

??????????????? /*

???????????????? * Android sets the locallyadministered bit to indicate that this is a

?????????? ??????* portable hotspot.? This will not work in simultaneous AP/STAmode,

???????????????? * nor with P2P.? Need to set the Donlge's MAC address, andthen use that.

???????????????? */

????????????????if(!memcmp(temp_addr, dhd->iflist[0]->mac_addr,

????????????????????????ETHER_ADDR_LEN)) {

??????????????????????? DHD_ERROR(("%sinterface [%s]: set locally administered bit in MAC\n",

??????????????????????? __func__,net->name));

??????????????????????? temp_addr[0] |= 0x02;

??????????????? }

??????? }

???????net->hard_header_len = ETH_HLEN + dhd->pub.hdrlen;

#if LINUX_VERSION_CODE >=KERNEL_VERSION(2, 6, 24)

????????net->ethtool_ops = &dhd_ethtool_ops;

#endif /* LINUX_VERSION_CODE>= KERNEL_VERSION(2, 6, 24) */

#ifdefined(CONFIG_WIRELESS_EXT)

#if WIRELESS_EXT < 19

????????net->get_wireless_stats = dhd_get_wireless_stats;

#endif /* WIRELESS_EXT < 19*/

#if WIRELESS_EXT > 12

????????net->wireless_handlers = (struct iw_handler_def*)&wl_iw_handler_def;???//這里的初始化工作很重要，之后的ioctl流程會(huì)涉及到對(duì)它的使用

#endif /* WIRELESS_EXT > 12*/

#endif /*defined(CONFIG_WIRELESS_EXT) */

??????? dhd->pub.rxsz =DBUS_RX_BUFFER_SIZE_DHD(net);

????????????????//設(shè)置設(shè)備地址

????????memcpy(net->dev_addr, temp_addr, ETHER_ADDR_LEN);

????????if ((err =register_netdev(net)) != 0) {?????? //注冊(cè)net

??????????????? DHD_ERROR(("couldn'tregister the net device, err %d\n", err));

??????????????? goto fail;

??????? }

???????

……

}

到這里net網(wǎng)絡(luò)設(shè)備就被注冊(cè)到系統(tǒng)中了，設(shè)備準(zhǔn)備好了就好對(duì)設(shè)備進(jìn)行訪問了

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