/drivers/net/phy/phy.c的状态机phy_state_machine分析

       本文分析基于PHY不采用中断方式，而且是固定速率模式，不采用自适应。

      在mii总线初始化过程中，mdio总线会通过mdiobus_scan()扫描挂载在该总线上的所有phy设备，并且通过phy_device_create()函数创建phy_device结构体。同时绑定marvell.c文件中对应的驱动。

    新创建的phy_device结构体成员初始化为：

        dev->speed = 0;dev->duplex = -1;dev->pause = dev->asym_pause = 0;dev->link = 1;dev->interface = PHY_INTERFACE_MODE_GMII;dev->autoneg = AUTONEG_ENABLE;dev->state = PHY_DOWN;

    在struct net_device_ops的ndo_open()函数会在网口被打开时调用。ndo_open()函数绑定PHY对应的驱动，并修改PHY的状态

        phydev->drv->config_init  //调用config_init驱动函数..........................         phydev->state = PHY_READY;         phy_prepare_link(phydev, handler);         phy_start_machine(phydev);

    phy_prepare_link()绑定phy_device结构体的adjust_link回调函数。然后启动PHY状态机。

   

phydev->supported &= (PHY_GBIT_FEATURES | SUPPORTED_Pause |SUPPORTED_Asym_Pause);phydev->advertising = phydev->supported;lp->link    = 0;lp->speed   = 0;lp->duplex  = -1;lp->phy_dev = phydev;phy_start(lp->phy_dev);

void phy_start(struct phy_device *phydev){mutex_lock(&phydev->lock);switch (phydev->state) {case PHY_STARTING:phydev->state = PHY_PENDING;break;case PHY_READY:phydev->state = PHY_UP;break;case PHY_HALTED:phydev->state = PHY_RESUMING;default:break;}mutex_unlock(&phydev->lock);}

    在PHY状态机中

case PHY_UP:needs_aneg = true;phydev->link_timeout = PHY_AN_TIMEOUT;break;。。。。    if (needs_aneg)        err = phy_start_aneg(phydev);

   标记1：phy_start_anegphy_start_aneg会修改

phydev->speed = settings[idx].speed;phydev->duplex = settings[idx].duplex;

然后调用驱动函数config_aneg()

    如果PHY不支持自适应，phy_start_aneg首先将PHY状态置为PHY_FORCING，否则置为PHY_AN

/** * phy_start_aneg - start auto-negotiation for this PHY device * @phydev: the phy_device struct * * Description: Sanitizes the settings (if we're not autonegotiating *   them), and then calls the driver's config_aneg function. *   If the PHYCONTROL Layer is operating, we change the state to *   reflect the beginning of Auto-negotiation or forcing. */int phy_start_aneg(struct phy_device *phydev){int err;mutex_lock(&phydev->lock);if (AUTONEG_DISABLE == phydev->autoneg)phy_sanitize_settings(phydev);err = phydev->drv->config_aneg(phydev);if (err < 0)goto out_unlock;if (phydev->state != PHY_HALTED) {if (AUTONEG_ENABLE == phydev->autoneg) {phydev->state = PHY_AN;phydev->link_timeout = PHY_AN_TIMEOUT;} else {phydev->state = PHY_FORCING;phydev->link_timeout = PHY_FORCE_TIMEOUT;}}out_unlock:mutex_unlock(&phydev->lock);return err;}

    PHY状态机对PHY_FORCING状态的处理如下：

case PHY_FORCING:err = genphy_update_link(phydev);if (err)break;if (phydev->link) {phydev->state = PHY_RUNNING;netif_carrier_on(phydev->attached_dev);} else {if (0 == phydev->link_timeout--)needs_aneg = true;}phydev->adjust_link(phydev->attached_dev);break;

1、genphy_update_link读取PHy的状态寄存器，更新phy_device->link;

2、如果link的话，phydev->state = PHY_RUNNING;调用adjust_link回调函数

case PHY_FORCING:err = genphy_update_link(phydev);if (err)break;if (phydev->link) {phydev->state = PHY_RUNNING;netif_carrier_on(phydev->attached_dev);} else {if (0 == phydev->link_timeout--)needs_aneg = true;}phydev->adjust_link(phydev->attached_dev);break;

3、没有link的话，继续调用phy_start_aneg，重复标记1开始的流程

PHY状态机对PHY_RUNNING状态的处理如下

case PHY_RUNNING:/* Only register a CHANGE if we are * polling or ignoring interrupts */if (!phy_interrupt_is_valid(phydev))phydev->state = PHY_CHANGELINK;break;

case PHY_CHANGELINK:err = phy_read_status(phydev);if (err)break;if (phydev->link) {phydev->state = PHY_RUNNING;netif_carrier_on(phydev->attached_dev);} else {phydev->state = PHY_NOLINK;netif_carrier_off(phydev->attached_dev);}phydev->adjust_link(phydev->attached_dev);if (phy_interrupt_is_valid(phydev))err = phy_config_interrupt(phydev,   PHY_INTERRUPT_ENABLED);break;case PHY_HALTED:if (phydev->link) {phydev->link = 0;netif_carrier_off(phydev->attached_dev);phydev->adjust_link(phydev->attached_dev);do_suspend = true;}break;

PHY_CHANGELINK状态处理分支：

读取PHY状态，如果link，置为PHY_RUNNING，调用adjust_link

否则置为PHY_NOLINK，调用adjust_link