http://blog.csdn.net/ylyuanlu/article/details/7711441
在drivers/mmc下面是mmc卡,SD卡和SDIO卡驱动部分,其中包括host驱动,card驱动和core部分,由于网络接口卡挂接在SDIO总线上,所以在此之前我们先看一下SDIO的驱动结构。其驱动在drivers/mmc目录下的结构为:
|-- mmc
| |-- card
| |-- core
| |-- host
主要关注的目录是core目录,这个目录是真个驱动的核心目录,是媒体卡的通用代码部分,包括core.c,host.c和sdio.c等。CORE 层完成了不同协议和规范的实现,并为HOST 层的驱动提供了接口函数,该目录完成sdio总线的注册操作,相应的ops操作,以及支持mmc的代码。详细的情况将在函数接口部分详细讨论。
Host目录是不同平台根据平台的特性而编写的host驱动。
全球有线和无线通信半导体市场的领导者Broadcom(博通)公司(Nasdaq:BRCM)宣布,推出最新无线组合芯片BCM4330,该芯片可支持更多媒体形式和数据应用,且不会增大智能手机、平板电脑及其他移动设备的尺寸或缩短其电池寿命。BCM4330在单个芯片上集成了业界领先的Broadcom 802.11n Wi-Fi、蓝牙和FM无线技术,与分立式半导体器件组成的解决方案相比,在成本、尺寸、功耗和性能上有显著优势,是移动设备的理想选择。
BCM4330采用了新的Wi-Fi和蓝牙标准,可支持新的、令人振奋的应用。例如,Broadcom BCM4330是业界第一款经过蓝牙4.0标准认证的组合芯片解决方案, 集成了蓝牙低功耗(BLE)标准。该标准使蓝牙技术能以超低功耗运行,因此BCM4330非常适用于需要很长电池寿命的系统,如无线传感器、医疗和健身监控设备等。BCM4330还支持Wi-Fi Direct™和蓝牙高速(HS)标准,因此采用BCM4330的移动设备能直接相互通信,而不必先连接到接入点、成为传统网络的一部分,从而为很多无线设备之间新的应用和使用模式创造了机会。
Broadcom一直支持所有主流的操作系统(OS)平台,如MicrosoftWindows和Windows Phone、Google Chrome、Android等等,而且不仅是BCM4330,所有蓝牙、WLAN和GPS芯片组都提供这样的支持。
Bcm4330驱动源码一般被厂商单独提供,如果要在开发的LINUX系统中(当然它还支持多种平台)使用该源码,可以添加到linux kernel源码树里,也可以单独组织存放,可以直接编译到kernel,也可以编译成模块,然后再系统启动的流程中或其他适当的实际加载到kernel中,一般建议单独组织并编译成模块在需要的时候加载如kernel。
|-- src
| |-- bcmsdio
| |-- dhd
| |--dongle
| |--include
| |-- shared
| |-- wl
这里主要内容到bcmsdio,dhd和wl三个目录下,bcm4330驱动的入口在dhd/sys/dhd_linux.c文件中的dhd_module()函数,设备的初始化和相关驱动注册都从这里开始,
以boardcom bcm4329芯片驱动为例,相应的函数流程图如下:
Platform_driver_register(wifi_device[_legacy])的调用将wifi_device[_legacy]驱动注册到系统中,wifi_device_legacy是为了兼容老版本的驱动。
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平台设备驱动的注册过程,那么在平台相关的代码区应该有wifi作为平台设备被初始化和注册的地方:
Path: kernel/arch/arm/mach-msm/board-mahimahi-wifi.c
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,
},
};
上面是对wifi_device设备的初始化,下面是对该设备的注册:
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); //表明在系统启动的后期会自动调用加载该模块
这样,通过上面的初始化和注册流程,wifi设备作为平台设备和驱动就可以握手成功了,这里的平台驱动只是对wifi设备的简单管理,如对wifi设备的挂起和恢复等操作了。但是在wifi设备初始化之前是不能够被挂起和恢复的,那么wifi设备是如何初始化的呢?
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;
}
这是wifi平台设备驱动注册时成功匹配wifi设备后调用的函数wifi_probe(),它的主要工作就是从wifi设备中获取终端资源,并获取wifi_platform_data类型结构赋予wifi_control_data变量,这一步很重要,下面就可以看出了它的重要性。然后调用wifi_set_power和wifi_set_carddetect函数给wifi芯片上电并检测。
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函数中调用wifi_control_data->set_power(on),wifi_control_data就是刚才说的那个重要变量,注意它是从wifi_device平台设备的wifi_platform_data获取的,那么看看上面的wifi_device初始化的代码:
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,
};
所以它实际调用的是mahimahi_wifi_power函数,该函数的定义在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;
}
调用gpio_set_value操作wifi芯片,给wifi芯片上电。那么来看看wifi_set_ carddetect函数究竟干了什么:
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;
}
同样会调用wifi_device的mahimahi_wifi_set_carddetect函数:
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代码:
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,
};
由上面代码;不难看出会有个地方调用mahimahi_wifi_status_register设置wifi_status_cb这个回调函数,可以跟踪这个mahimahi_wifi_data结构体,来看看它被传递给了谁:
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,
……
}
可以跟踪到这里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]; //因为传过来的controller是1,所以下面注册的是第一个平台设备
pdev->dev.platform_data= plat; //被传递给平台设备的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
}
那么这个平台设备是什么呢,就是sd卡控制器,也就是前面说的host驱动所驱动的主机控制设备。
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);
}
驱动成功匹配设备后,调用probe函数:
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调用msmsdcc_check_status函数:
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调用mmc_detect_change函数:
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被调用了,这个函数触发了一个延时工作:
void mmc_detect_change(structmmc_host *host, unsigned long delay)
{
……
mmc_schedule_delayed_work(&host->detect, delay);
}
这个时候它会在delay时间后,执行host->detect延时工作对应的函数,在host驱动注册并匹配设备成功后执行的probe函数里,会调用mmc_alloc_host动态创建一个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中一个很重要的函数,它遵照 SDIO 卡协议的 SDIO 卡启动过程,包括了非激活模式、卡识别模式和数据传输模式三种模式共九种状态的转换,你需要参照相关规范来理解。
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;
}
......
}
这个mmc_attach_sdio函数很重要,它是SDIO卡的初始化的起点,主要工作包括:匹配SDIO卡的工作电压,分配并初始化mmc_card结构,然后注册mmc_card到系统中:
/*
* 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卡工作电压
……
/*
* Detect and init the card.
*/
err = mmc_sdio_init_card(host, host->ocr, NULL, 0);//检测,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]); //将sdio_func加入系统
if (err)
goto remove_added;
}
return 0;
......
}
这样,SDIO卡已经初始化成功并添加到了驱动中。上面说的过程是在SDIO设备注册时的调用流程,mmc_rescan是整个流程主体部分,由它来完成SDIO设备的初始化和添加。其实上面的流程只是创建,初始化,添加SDIO设备的一条线,还有另外的两条线也会调用mmc_rescan函数进行SDIO设备的上述操作:
(1) 加载SDIO host驱动模块
(2) SDIO设备中断
Host作为平台设备被注册,前面也有列出相应源码:
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函数会调用mmc_alloc_host函数(代码前面已经贴出)来创建mmc_host结构变量,进行必要的初始化之后,调用mmc_add_host函数将它添加到驱动里面:
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定义如下:
void mmc_start_host(structmmc_host *host)
{
mmc_power_off(host);
mmc_detect_change(host, 0);
}
mmc_power_off中对 ios进行了设置,然后调用 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) 中的关键语句 host->ops->set_ios(host, ios),实际上在host驱动的probe函数中就已经对host->ops进行了初始化:
……
/*
* 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,
};
所以实际上调用的是msmsdcc_set_ios,关于这个函数就不介绍了,可以参考源码,再看 mmc_detect_change(host, 0),最后一句是:
mmc_schedule_delayed_work(&host->detect,delay);
实际上就是调用我们前面说的延时函数 mmc_rescan,后面的流程是一样的。
SDIO设备通过SDIO总线与host相连,SDIO总线的DAT[1]即pin8可以作为中断线使用,当SDIO设备向host产生中断时,host会对终端做出相应的动作,在host驱动的probe函数中申请并注册相应的中断函数:
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;
}
}
......
}
当产生相应的中断时调用msmsdcc_platform_status_irq中断处理函数,这个函数的处理流程:
msmsdcc_platform_status_irq—>
msmsdcc_check_statusà
mmc_detect_changeà
mmc_rescanà
那么,这里为何调用mmc_rescan呢?因为前面说过mmc_rescanrescan函数主要用于SDIO设备的初始化,如果SDIO设备产生中断不应该是已经初始化可以使用了吗?其实mmc_rescan还有其它的工作,从函数名就能看出来它还有再扫描检测功能,即如果设备产生了中断,mmc_rescan函数一开始就会再次检测所有挂接在该host上的所有SDIO设备,确认是否存在,如果不存在就做相应的释放工作,以确保数据的一致性。如果检测到了新的设备那么它就会创建一个新的mmc_card,初始化并添加该设备。
中断引发的调用mmc_rescan动作的意义:实现了SDIO设备的热插拔功能。
此调用流程由dhd_bus_register发起,通过sdio_register_driver注册一个sdio设备驱动,然后通过dhdsdio_probe初始化并注册一个网络设备,网络设备的注册标志着wifi驱动已经成功加载,关于网络设备的创建,初始化和注册后面会有详细介绍,先来理一下上面的调用流程,:
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
这里注意上面两个红色标记的函数,sdio_register_driver注册了一个sdio设备,在匹配成功后调用bcmsdh_sdmmc_probe函数,这个函数会调用bcmsdh_probe。这里有一点要注意:浏览bcmsdh_linux.c文件可以看出,在bcmsdh_register函数中,当定义了BCMLXSDMMC宏时,会调用sdio_function_init函数,否则调用driver_register函数:
int
bcmsdh_register(bcmsdh_driver_t*driver)
{
int error = 0;
drvinfo = *driver; //注意这里,后面会介绍到它的用处
#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的调用出现,所以这里实际上BCMLXSDMMC宏被定义了,bcmsdh_probe函数只是作为一个普通函数被调用,如果不定义该宏,那么bcmsdh_probe函数会被作为驱动匹配设备后第一个调用的函数而被自动调用。
再看看dhdsdio_probe函数调用的玄机,从上面的bcmsdh_register函数可以看出它的参数被传递给了drvinfo,看看bcmsdh_register的调用地方:
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);
}
上面传递的参数是dhd_sdio结构变量,被用两个函数初始化了,那么哪一个是attach呢?需要找到定义bcmsdh_driver_t结构定义的地方:
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;
没错,就是第一个dhdsdio_probe函数,再来看看什么地方调用了这个attach函数:
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;
......
}
红色部分的函数调用是drvinfo.attach,就是上面传递过来的dhdsdio_probe函数了,仔细阅读你会发现上面那个bcmsdh_driver_t结构体定义的地方有个说明,即把该结构的成员函数当做callback函数来使用,这就是它的用意所在。
上面是网络设备注册流程,在dhdsdio_probe函数中先后对dhd_attach和dhd_net_attach两个函数调用,dhd_attach主要用于创建和初始化dhd_info_t和net_device两个结构变量,然后调用dhd_add_if将创建的net_device变量添加到dhd_info_t变量的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)))) { //网络设备的创建
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的创建
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) //将前面创建的net添加到iflist列表中
goto fail;
dhd_state |= DHD_ATTACH_STATE_ADD_IF;
......
Memcpy(netdev_priv(net), &dhd, sizeof(dhd)); //关联dhd和net
//dhd的初始化工作
}
Dhd_add_if的添加网络接口流程:
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); //如果已经存在,释放net成员
}
} else
if ((ifp = MALLOC(dhd->pub.osh,sizeof(dhd_if_t))) == NULL) {
DHD_ERROR(("%s: OOM - dhd_if_t\n", __FUNCTION__)); //否则,创建一个dhd_if_t结构变量
return -ENOMEM;
}
memset(ifp, 0, sizeof(dhd_if_t));
ifp->info = dhd; //进行系列初始化,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即一个net_device变量
return 0;
}
这样,一个net_device网路设备就被添加到了接口管理列表中了,但是这是网路设备还没有完成初始化和注册工作,bcmsdio_probe函数随后对dhd_net_attach的调用完成了这个操作:
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; //首先从刚才添加的接口列表中取出net,然后进行下面的系列初始化工作
ASSERT(net);
//根据内核版本信息,选择对net成员函数的初始化方式,假设是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; //这里的初始化工作很重要,之后的ioctl流程会涉及到对它的使用
#endif /* WIRELESS_EXT > 12*/
#endif /*defined(CONFIG_WIRELESS_EXT) */
dhd->pub.rxsz =DBUS_RX_BUFFER_SIZE_DHD(net);
//设置设备地址
memcpy(net->dev_addr, temp_addr, ETHER_ADDR_LEN);
if ((err =register_netdev(net)) != 0) { //注册net
DHD_ERROR(("couldn'tregister the net device, err %d\n", err));
goto fail;
}
……
}
到这里net网络设备就被注册到系统中了,设备准备好了就好对设备进行访问了