linux mmc設備掛載流程解析

linux的emmc驅動在drivers\mmc\card\block.c，其mmc_dirver結構體如下：

static struct mmc_driver mmc_driver = {
.drv= {
.name = "mmcblk",
},
.probe  = mmc_blk_probe,
.remove  = mmc_blk_remove,
.suspend  = mmc_blk_suspend,
.resume  = mmc_blk_resume,
};

根據以往平臺總線驅動模型的經驗來看的話，內核裏應該有mmc_devices結構體，並且

其name也爲"mmcblk"，這樣其probe函數將被調用，但是搜索整個內核文件並沒有發現mmc_devices。

現在我們分析一下mmc_blk_probe什麼時候被調用。

static int __init mmc_blk_init(void)             //drivers\mmc\card\block.c
{
     res = mmc_register_driver(&mmc_driver);     //註冊mmc_driver
}

int mmc_register_driver(struct mmc_driver *drv)      //drivers\mmc\core\bus.c
{
     drv->drv.bus = &mmc_bus_type;                         //mmc設備是掛載在mmc總線上的
     return driver_register(&drv->drv);                        //註冊mmc驅動
}

int driver_register(struct device_driver *drv)        //drivers\base\driver.c
{
     other = driver_find(drv->name, drv->bus);      //在總線上查找是否已經註冊過此驅動
     if (other) {
          put_driver(other);
          printk(KERN_ERR "Error: Driver '%s' is already registered, "
               "aborting...\n", drv->name);
          return -EBUSY;
     }

     ret = bus_add_driver(drv);                            //如果沒有註冊過，則註冊此驅動
}

int bus_add_driver(struct device_driver *drv)        //drivers\base\bus.c
{
     error = driver_attach(drv);                           
     error = driver_create_file(drv, &driver_attr_uevent);
}

//try to bind driver to devices

int driver_attach(struct device_driver *drv)         //drivers/base/dd.c
{
     return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);  

    //__driver_attach的裏面device的查找還沒搞清楚
}

static int __driver_attach(struct device *dev, void *data)     //drivers/base/dd.c

{

     if (!driver_match_device(drv, dev))
return 0;

     driver_probe_device(drv, dev);

}

static inline int driver_match_device(struct device_driver *drv,      //drivers/base/base.h
     struct device *dev)
{

     //這裏調用了mmc總線的match函數
     return drv->bus->match ? drv->bus->match(dev, drv) : 1;
}

static int mmc_bus_match(struct device *dev, struct device_driver *drv)       //drivers\mmc\core\bus.c
{

      //mmc總線的match直接返回了1
      return 1;
}

int driver_probe_device(struct device_driver *drv, struct device *dev)      //drivers/base/dd.c
{
     really_probe(dev, drv);
}

static int really_probe(struct device *dev, struct device_driver *drv)      //drivers/base/dd.c
{
     dev->bus->probe(dev);       //這裏調用總線的probe函數
}

static int mmc_bus_probe(struct device *dev)      //drivers\mmc\core\bus.c
{
return drv->probe(card);      //最終mmc總線的probe函數調用mmc_driver的probe函數
}