linux网络设备—mdio总线

一.结构体

 struct mii_bus {
     const char *name;   //总线名
     char id[MII_BUS_ID_SIZE];   //id
     void *priv; //私有数据
     int (*read)(struct mii_bus *bus, int phy_id, int regnum);   //读方法
     int (*write)(struct mii_bus *bus, int phy_id, int regnum, u16 val); //写方法
     int (*reset)(struct mii_bus *bus);  //复位
     struct mutex mdio_lock;
     struct device *parent;  //父设备
     enum {
         MDIOBUS_ALLOCATED = 1,
         MDIOBUS_REGISTERED,
         MDIOBUS_UNREGISTERED,
         MDIOBUS_RELEASED,
     } state;    //总线状态
     struct device dev;  //设备文件
     struct phy_device *phy_map[PHY_MAX_ADDR];   //PHY设备数组
     u32 phy_mask;
     int *irq;   //中断
 };

二.初始化过程

在phy_init函数中调用了mdio_bus_init初始化mdio总线

 int __init mdio_bus_init(void)
 {
     int ret;
     ret = class_register(&mdio_bus_class);  //注册设备类
     if (!ret) {
         ret = bus_register(&mdio_bus_type); //注册mdio总线
         if (ret)
             class_unregister(&mdio_bus_class);
     }
     return ret;
 }

设备类"/sys/class/mdio_bus"

 static struct class mdio_bus_class = {
     .name       = "mdio_bus",
     .dev_release    = mdiobus_release,
 };

总线类型"/sys/bus/mdio"

 struct bus_type mdio_bus_type = {
     .name       = "mdio_bus",
     .match      = mdio_bus_match,   //匹配方法
     .pm     = MDIO_BUS_PM_OPS,
 };
 EXPORT_SYMBOL(mdio_bus_type);

三.mdio总线注册
1.调用mdiobus_alloc函数分配内存

 struct mii_bus *mdiobus_alloc(void)
 {
     struct mii_bus *bus;
     bus = kzalloc(sizeof(*bus), GFP_KERNEL);    //分配内存
     if (bus != NULL)
         bus->state = MDIOBUS_ALLOCATED;
     return bus;
 }
 EXPORT_SYMBOL(mdiobus_alloc);

2.填充mii_bus的结构体成员

 mii_bus->name    = ;
 mii_bus->read    = ;
 mii_bus->write   = ;
 mii_bus->reset   = ;
 mii_bus->parent  = ;
 mii_bus->priv    = ;
 mii_bus->id  = ;

3.注册mii_bus

 int mdiobus_register(struct mii_bus *bus)
 {
     int i, err;
     if (NULL == bus || NULL == bus->name || NULL == bus->read ||NULL == bus->write)
         return -EINVAL;
     BUG_ON(bus->state != MDIOBUS_ALLOCATED &&bus->state != MDIOBUS_UNREGISTERED);
     bus->dev.parent = bus->parent;
     bus->dev.class = &mdio_bus_class;    //总线设备类"/sys/bus/mdio_bus"
     bus->dev.groups = NULL;
     dev_set_name(&bus->dev, "%s", bus->id);   //设置总线设备名
     err = device_register(&bus->dev);    //注册设备文件
     if (err) {
         printk(KERN_ERR "mii_bus %s failed to register\n", bus->id);
         return -EINVAL;
     }
     mutex_init(&bus->mdio_lock);
     if (bus->reset)
         bus->reset(bus); //总线复位
     for (i = 0; i < PHY_MAX_ADDR; i++) {
         if ((bus->phy_mask & (1 << i)) == 0) {
             struct phy_device *phydev;
             phydev = mdiobus_scan(bus, i);  //扫描phy设备
             if (IS_ERR(phydev)) {
                 err = PTR_ERR(phydev);
                 goto error;
             }
         }
     }
     bus->state = MDIOBUS_REGISTERED; //状态设置为已注册
     pr_info("%s: probed\n", bus->name);
     return 0;
 error:
     while (--i >= 0) {
         if (bus->phy_map[i])
             device_unregister(&bus->phy_map[i]->dev);
     }
     device_del(&bus->dev);
     return err;
 }
 EXPORT_SYMBOL(mdiobus_register);

调用了mdiobus_scan函数

 struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
 {
     struct phy_device *phydev;
     int err;
     phydev = get_phy_device(bus, addr); //获取创建phy设备
     if (IS_ERR(phydev) || phydev == NULL)
         return phydev;
     err = phy_device_register(phydev);  //注册phy设备
     if (err) {
         phy_device_free(phydev);
         return NULL;
     }
     return phydev;
 }
 EXPORT_SYMBOL(mdiobus_scan);

动态地创建了PHY设备

四.mii、mdio、phy、mac关系图

http://blog.csdn.net/orz415678659/article/details/9370827