CRIS: Move common Kconfig variable ETRAX_RTC to arch independet Kconfig.

[wrt350n-kernel.git] / drivers / net / phy / phy.c

/*
 * drivers/net/phy/phy.c
 *
 * Framework for configuring and reading PHY devices
 * Based on code in sungem_phy.c and gianfar_phy.c
 *
 * Author: Andy Fleming
 *
 * Copyright (c) 2004 Freescale Semiconductor, Inc.
 * Copyright (c) 2006, 2007  Maciej W. Rozycki
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 *
 */
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>
#include <linux/timer.h>
#include <linux/workqueue.h>

#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>

/**
 * phy_print_status - Convenience function to print out the current phy status
 * @phydev: the phy_device struct
 */
void phy_print_status(struct phy_device *phydev)
{
        pr_info("PHY: %s - Link is %s", phydev->dev.bus_id,
                        phydev->link ? "Up" : "Down");
        if (phydev->link)
                printk(" - %d/%s", phydev->speed,
                                DUPLEX_FULL == phydev->duplex ?
                                "Full" : "Half");

        printk("\n");
}
EXPORT_SYMBOL(phy_print_status);


/**
 * phy_read - Convenience function for reading a given PHY register
 * @phydev: the phy_device struct
 * @regnum: register number to read
 *
 * NOTE: MUST NOT be called from interrupt context,
 * because the bus read/write functions may wait for an interrupt
 * to conclude the operation.
 */
int phy_read(struct phy_device *phydev, u16 regnum)
{
        int retval;
        struct mii_bus *bus = phydev->bus;

        BUG_ON(in_interrupt());

        mutex_lock(&bus->mdio_lock);
        retval = bus->read(bus, phydev->addr, regnum);
        mutex_unlock(&bus->mdio_lock);

        return retval;
}
EXPORT_SYMBOL(phy_read);

/**
 * phy_write - Convenience function for writing a given PHY register
 * @phydev: the phy_device struct
 * @regnum: register number to write
 * @val: value to write to @regnum
 *
 * NOTE: MUST NOT be called from interrupt context,
 * because the bus read/write functions may wait for an interrupt
 * to conclude the operation.
 */
int phy_write(struct phy_device *phydev, u16 regnum, u16 val)
{
        int err;
        struct mii_bus *bus = phydev->bus;

        BUG_ON(in_interrupt());

        mutex_lock(&bus->mdio_lock);
        err = bus->write(bus, phydev->addr, regnum, val);
        mutex_unlock(&bus->mdio_lock);

        return err;
}
EXPORT_SYMBOL(phy_write);

/**
 * phy_clear_interrupt - Ack the phy device's interrupt
 * @phydev: the phy_device struct
 *
 * If the @phydev driver has an ack_interrupt function, call it to
 * ack and clear the phy device's interrupt.
 *
 * Returns 0 on success on < 0 on error.
 */
int phy_clear_interrupt(struct phy_device *phydev)
{
        int err = 0;

        if (phydev->drv->ack_interrupt)
                err = phydev->drv->ack_interrupt(phydev);

        return err;
}

/**
 * phy_config_interrupt - configure the PHY device for the requested interrupts
 * @phydev: the phy_device struct
 * @interrupts: interrupt flags to configure for this @phydev
 *
 * Returns 0 on success on < 0 on error.
 */
int phy_config_interrupt(struct phy_device *phydev, u32 interrupts)
{
        int err = 0;

        phydev->interrupts = interrupts;
        if (phydev->drv->config_intr)
                err = phydev->drv->config_intr(phydev);

        return err;
}


/**
 * phy_aneg_done - return auto-negotiation status
 * @phydev: target phy_device struct
 *
 * Description: Reads the status register and returns 0 either if
 *   auto-negotiation is incomplete, or if there was an error.
 *   Returns BMSR_ANEGCOMPLETE if auto-negotiation is done.
 */
static inline int phy_aneg_done(struct phy_device *phydev)
{
        int retval;

        retval = phy_read(phydev, MII_BMSR);

        return (retval < 0) ? retval : (retval & BMSR_ANEGCOMPLETE);
}

/* A structure for mapping a particular speed and duplex
 * combination to a particular SUPPORTED and ADVERTISED value */
struct phy_setting {
        int speed;
        int duplex;
        u32 setting;
};

/* A mapping of all SUPPORTED settings to speed/duplex */
static const struct phy_setting settings[] = {
        {
                .speed = 10000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_10000baseT_Full,
        },
        {
                .speed = SPEED_1000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_1000baseT_Full,
        },
        {
                .speed = SPEED_1000,
                .duplex = DUPLEX_HALF,
                .setting = SUPPORTED_1000baseT_Half,
        },
        {
                .speed = SPEED_100,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_100baseT_Full,
        },
        {
                .speed = SPEED_100,
                .duplex = DUPLEX_HALF,
                .setting = SUPPORTED_100baseT_Half,
        },
        {
                .speed = SPEED_10,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_10baseT_Full,
        },
        {
                .speed = SPEED_10,
                .duplex = DUPLEX_HALF,
                .setting = SUPPORTED_10baseT_Half,
        },
};

#define MAX_NUM_SETTINGS ARRAY_SIZE(settings)

/**
 * phy_find_setting - find a PHY settings array entry that matches speed & duplex
 * @speed: speed to match
 * @duplex: duplex to match
 *
 * Description: Searches the settings array for the setting which
 *   matches the desired speed and duplex, and returns the index
 *   of that setting.  Returns the index of the last setting if
 *   none of the others match.
 */
static inline int phy_find_setting(int speed, int duplex)
{
        int idx = 0;

        while (idx < ARRAY_SIZE(settings) &&
                        (settings[idx].speed != speed ||
                        settings[idx].duplex != duplex))
                idx++;

        return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
}

/**
 * phy_find_valid - find a PHY setting that matches the requested features mask
 * @idx: The first index in settings[] to search
 * @features: A mask of the valid settings
 *
 * Description: Returns the index of the first valid setting less
 *   than or equal to the one pointed to by idx, as determined by
 *   the mask in features.  Returns the index of the last setting
 *   if nothing else matches.
 */
static inline int phy_find_valid(int idx, u32 features)
{
        while (idx < MAX_NUM_SETTINGS && !(settings[idx].setting & features))
                idx++;

        return idx < MAX_NUM_SETTINGS ? idx : MAX_NUM_SETTINGS - 1;
}

/**
 * phy_sanitize_settings - make sure the PHY is set to supported speed and duplex
 * @phydev: the target phy_device struct
 *
 * Description: Make sure the PHY is set to supported speeds and
 *   duplexes.  Drop down by one in this order:  1000/FULL,
 *   1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
 */
void phy_sanitize_settings(struct phy_device *phydev)
{
        u32 features = phydev->supported;
        int idx;

        /* Sanitize settings based on PHY capabilities */
        if ((features & SUPPORTED_Autoneg) == 0)
                phydev->autoneg = AUTONEG_DISABLE;

        idx = phy_find_valid(phy_find_setting(phydev->speed, phydev->duplex),
                        features);

        phydev->speed = settings[idx].speed;
        phydev->duplex = settings[idx].duplex;
}
EXPORT_SYMBOL(phy_sanitize_settings);

/**
 * phy_ethtool_sset - generic ethtool sset function, handles all the details
 * @phydev: target phy_device struct
 * @cmd: ethtool_cmd
 *
 * A few notes about parameter checking:
 * - We don't set port or transceiver, so we don't care what they
 *   were set to.
 * - phy_start_aneg() will make sure forced settings are sane, and
 *   choose the next best ones from the ones selected, so we don't
 *   care if ethtool tries to give us bad values.
 */
int phy_ethtool_sset(struct phy_device *phydev, struct ethtool_cmd *cmd)
{
        if (cmd->phy_address != phydev->addr)
                return -EINVAL;

        /* We make sure that we don't pass unsupported
         * values in to the PHY */
        cmd->advertising &= phydev->supported;

        /* Verify the settings we care about. */
        if (cmd->autoneg != AUTONEG_ENABLE && cmd->autoneg != AUTONEG_DISABLE)
                return -EINVAL;

        if (cmd->autoneg == AUTONEG_ENABLE && cmd->advertising == 0)
                return -EINVAL;

        if (cmd->autoneg == AUTONEG_DISABLE
                        && ((cmd->speed != SPEED_1000
                                        && cmd->speed != SPEED_100
                                        && cmd->speed != SPEED_10)
                                || (cmd->duplex != DUPLEX_HALF
                                        && cmd->duplex != DUPLEX_FULL)))
                return -EINVAL;

        phydev->autoneg = cmd->autoneg;

        phydev->speed = cmd->speed;

        phydev->advertising = cmd->advertising;

        if (AUTONEG_ENABLE == cmd->autoneg)
                phydev->advertising |= ADVERTISED_Autoneg;
        else
                phydev->advertising &= ~ADVERTISED_Autoneg;

        phydev->duplex = cmd->duplex;

        /* Restart the PHY */
        phy_start_aneg(phydev);

        return 0;
}
EXPORT_SYMBOL(phy_ethtool_sset);

int phy_ethtool_gset(struct phy_device *phydev, struct ethtool_cmd *cmd)
{
        cmd->supported = phydev->supported;

        cmd->advertising = phydev->advertising;

        cmd->speed = phydev->speed;
        cmd->duplex = phydev->duplex;
        cmd->port = PORT_MII;
        cmd->phy_address = phydev->addr;
        cmd->transceiver = XCVR_EXTERNAL;
        cmd->autoneg = phydev->autoneg;

        return 0;
}
EXPORT_SYMBOL(phy_ethtool_gset);

/**
 * phy_mii_ioctl - generic PHY MII ioctl interface
 * @phydev: the phy_device struct
 * @mii_data: MII ioctl data
 * @cmd: ioctl cmd to execute
 *
 * Note that this function is currently incompatible with the
 * PHYCONTROL layer.  It changes registers without regard to
 * current state.  Use at own risk.
 */
int phy_mii_ioctl(struct phy_device *phydev,
                struct mii_ioctl_data *mii_data, int cmd)
{
        u16 val = mii_data->val_in;

        switch (cmd) {
        case SIOCGMIIPHY:
                mii_data->phy_id = phydev->addr;
                break;
        case SIOCGMIIREG:
                mii_data->val_out = phy_read(phydev, mii_data->reg_num);
                break;

        case SIOCSMIIREG:
                if (!capable(CAP_NET_ADMIN))
                        return -EPERM;

                if (mii_data->phy_id == phydev->addr) {
                        switch(mii_data->reg_num) {
                        case MII_BMCR:
                                if ((val & (BMCR_RESET|BMCR_ANENABLE)) == 0)
                                        phydev->autoneg = AUTONEG_DISABLE;
                                else
                                        phydev->autoneg = AUTONEG_ENABLE;
                                if ((!phydev->autoneg) && (val & BMCR_FULLDPLX))
                                        phydev->duplex = DUPLEX_FULL;
                                else
                                        phydev->duplex = DUPLEX_HALF;
                                if ((!phydev->autoneg) &&
                                                (val & BMCR_SPEED1000))
                                        phydev->speed = SPEED_1000;
                                else if ((!phydev->autoneg) &&
                                                (val & BMCR_SPEED100))
                                        phydev->speed = SPEED_100;
                                break;
                        case MII_ADVERTISE:
                                phydev->advertising = val;
                                break;
                        default:
                                /* do nothing */
                                break;
                        }
                }

                phy_write(phydev, mii_data->reg_num, val);
                
                if (mii_data->reg_num == MII_BMCR 
                                && val & BMCR_RESET
                                && phydev->drv->config_init)
                        phydev->drv->config_init(phydev);
                break;

        default:
                return -ENOTTY;
        }

        return 0;
}
EXPORT_SYMBOL(phy_mii_ioctl);

/**
 * 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;
}
EXPORT_SYMBOL(phy_start_aneg);


static void phy_change(struct work_struct *work);
static void phy_state_machine(struct work_struct *work);
static void phy_timer(unsigned long data);

/**
 * phy_start_machine - start PHY state machine tracking
 * @phydev: the phy_device struct
 * @handler: callback function for state change notifications
 *
 * Description: The PHY infrastructure can run a state machine
 *   which tracks whether the PHY is starting up, negotiating,
 *   etc.  This function starts the timer which tracks the state
 *   of the PHY.  If you want to be notified when the state changes,
 *   pass in the callback @handler, otherwise, pass NULL.  If you
 *   want to maintain your own state machine, do not call this
 *   function.
 */
void phy_start_machine(struct phy_device *phydev,
                void (*handler)(struct net_device *))
{
        phydev->adjust_state = handler;

        INIT_WORK(&phydev->state_queue, phy_state_machine);
        init_timer(&phydev->phy_timer);
        phydev->phy_timer.function = &phy_timer;
        phydev->phy_timer.data = (unsigned long) phydev;
        mod_timer(&phydev->phy_timer, jiffies + HZ);
}

/**
 * phy_stop_machine - stop the PHY state machine tracking
 * @phydev: target phy_device struct
 *
 * Description: Stops the state machine timer, sets the state to UP
 *   (unless it wasn't up yet). This function must be called BEFORE
 *   phy_detach.
 */
void phy_stop_machine(struct phy_device *phydev)
{
        del_timer_sync(&phydev->phy_timer);
        cancel_work_sync(&phydev->state_queue);

        mutex_lock(&phydev->lock);
        if (phydev->state > PHY_UP)
                phydev->state = PHY_UP;
        mutex_unlock(&phydev->lock);

        phydev->adjust_state = NULL;
}

/**
 * phy_force_reduction - reduce PHY speed/duplex settings by one step
 * @phydev: target phy_device struct
 *
 * Description: Reduces the speed/duplex settings by one notch,
 *   in this order--
 *   1000/FULL, 1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
 *   The function bottoms out at 10/HALF.
 */
static void phy_force_reduction(struct phy_device *phydev)
{
        int idx;

        idx = phy_find_setting(phydev->speed, phydev->duplex);
        
        idx++;

        idx = phy_find_valid(idx, phydev->supported);

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

        pr_info("Trying %d/%s\n", phydev->speed,
                        DUPLEX_FULL == phydev->duplex ?
                        "FULL" : "HALF");
}


/**
 * phy_error - enter HALTED state for this PHY device
 * @phydev: target phy_device struct
 *
 * Moves the PHY to the HALTED state in response to a read
 * or write error, and tells the controller the link is down.
 * Must not be called from interrupt context, or while the
 * phydev->lock is held.
 */
void phy_error(struct phy_device *phydev)
{
        mutex_lock(&phydev->lock);
        phydev->state = PHY_HALTED;
        mutex_unlock(&phydev->lock);
}

/**
 * phy_interrupt - PHY interrupt handler
 * @irq: interrupt line
 * @phy_dat: phy_device pointer
 *
 * Description: When a PHY interrupt occurs, the handler disables
 * interrupts, and schedules a work task to clear the interrupt.
 */
static irqreturn_t phy_interrupt(int irq, void *phy_dat)
{
        struct phy_device *phydev = phy_dat;

        if (PHY_HALTED == phydev->state)
                return IRQ_NONE;                /* It can't be ours.  */

        /* The MDIO bus is not allowed to be written in interrupt
         * context, so we need to disable the irq here.  A work
         * queue will write the PHY to disable and clear the
         * interrupt, and then reenable the irq line. */
        disable_irq_nosync(irq);
        atomic_inc(&phydev->irq_disable);

        schedule_work(&phydev->phy_queue);

        return IRQ_HANDLED;
}

/**
 * phy_enable_interrupts - Enable the interrupts from the PHY side
 * @phydev: target phy_device struct
 */
int phy_enable_interrupts(struct phy_device *phydev)
{
        int err;

        err = phy_clear_interrupt(phydev);

        if (err < 0)
                return err;

        err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);

        return err;
}
EXPORT_SYMBOL(phy_enable_interrupts);

/**
 * phy_disable_interrupts - Disable the PHY interrupts from the PHY side
 * @phydev: target phy_device struct
 */
int phy_disable_interrupts(struct phy_device *phydev)
{
        int err;

        /* Disable PHY interrupts */
        err = phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);

        if (err)
                goto phy_err;

        /* Clear the interrupt */
        err = phy_clear_interrupt(phydev);

        if (err)
                goto phy_err;

        return 0;

phy_err:
        phy_error(phydev);

        return err;
}
EXPORT_SYMBOL(phy_disable_interrupts);

/**
 * phy_start_interrupts - request and enable interrupts for a PHY device
 * @phydev: target phy_device struct
 *
 * Description: Request the interrupt for the given PHY.
 *   If this fails, then we set irq to PHY_POLL.
 *   Otherwise, we enable the interrupts in the PHY.
 *   This should only be called with a valid IRQ number.
 *   Returns 0 on success or < 0 on error.
 */
int phy_start_interrupts(struct phy_device *phydev)
{
        int err = 0;

        INIT_WORK(&phydev->phy_queue, phy_change);

        atomic_set(&phydev->irq_disable, 0);
        if (request_irq(phydev->irq, phy_interrupt,
                                IRQF_SHARED,
                                "phy_interrupt",
                                phydev) < 0) {
                printk(KERN_WARNING "%s: Can't get IRQ %d (PHY)\n",
                                phydev->bus->name,
                                phydev->irq);
                phydev->irq = PHY_POLL;
                return 0;
        }

        err = phy_enable_interrupts(phydev);

        return err;
}
EXPORT_SYMBOL(phy_start_interrupts);

/**
 * phy_stop_interrupts - disable interrupts from a PHY device
 * @phydev: target phy_device struct
 */
int phy_stop_interrupts(struct phy_device *phydev)
{
        int err;

        err = phy_disable_interrupts(phydev);

        if (err)
                phy_error(phydev);

        free_irq(phydev->irq, phydev);

        /*
         * Cannot call flush_scheduled_work() here as desired because
         * of rtnl_lock(), but we do not really care about what would
         * be done, except from enable_irq(), so cancel any work
         * possibly pending and take care of the matter below.
         */
        cancel_work_sync(&phydev->phy_queue);
        /*
         * If work indeed has been cancelled, disable_irq() will have
         * been left unbalanced from phy_interrupt() and enable_irq()
         * has to be called so that other devices on the line work.
         */
        while (atomic_dec_return(&phydev->irq_disable) >= 0)
                enable_irq(phydev->irq);

        return err;
}
EXPORT_SYMBOL(phy_stop_interrupts);


/**
 * phy_change - Scheduled by the phy_interrupt/timer to handle PHY changes
 * @work: work_struct that describes the work to be done
 */
static void phy_change(struct work_struct *work)
{
        int err;
        struct phy_device *phydev =
                container_of(work, struct phy_device, phy_queue);

        err = phy_disable_interrupts(phydev);

        if (err)
                goto phy_err;

        mutex_lock(&phydev->lock);
        if ((PHY_RUNNING == phydev->state) || (PHY_NOLINK == phydev->state))
                phydev->state = PHY_CHANGELINK;
        mutex_unlock(&phydev->lock);

        atomic_dec(&phydev->irq_disable);
        enable_irq(phydev->irq);

        /* Reenable interrupts */
        if (PHY_HALTED != phydev->state)
                err = phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);

        if (err)
                goto irq_enable_err;

        return;

irq_enable_err:
        disable_irq(phydev->irq);
        atomic_inc(&phydev->irq_disable);
phy_err:
        phy_error(phydev);
}

/**
 * phy_stop - Bring down the PHY link, and stop checking the status
 * @phydev: target phy_device struct
 */
void phy_stop(struct phy_device *phydev)
{
        mutex_lock(&phydev->lock);

        if (PHY_HALTED == phydev->state)
                goto out_unlock;

        if (phydev->irq != PHY_POLL) {
                /* Disable PHY Interrupts */
                phy_config_interrupt(phydev, PHY_INTERRUPT_DISABLED);

                /* Clear any pending interrupts */
                phy_clear_interrupt(phydev);
        }

        phydev->state = PHY_HALTED;

out_unlock:
        mutex_unlock(&phydev->lock);

        /*
         * Cannot call flush_scheduled_work() here as desired because
         * of rtnl_lock(), but PHY_HALTED shall guarantee phy_change()
         * will not reenable interrupts.
         */
}


/**
 * phy_start - start or restart a PHY device
 * @phydev: target phy_device struct
 *
 * Description: Indicates the attached device's readiness to
 *   handle PHY-related work.  Used during startup to start the
 *   PHY, and after a call to phy_stop() to resume operation.
 *   Also used to indicate the MDIO bus has cleared an error
 *   condition.
 */
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);
}
EXPORT_SYMBOL(phy_stop);
EXPORT_SYMBOL(phy_start);

/**
 * phy_state_machine - Handle the state machine
 * @work: work_struct that describes the work to be done
 *
 * Description: Scheduled by the state_queue workqueue each time
 *   phy_timer is triggered.
 */
static void phy_state_machine(struct work_struct *work)
{
        struct phy_device *phydev =
                        container_of(work, struct phy_device, state_queue);
        int needs_aneg = 0;
        int err = 0;

        mutex_lock(&phydev->lock);

        if (phydev->adjust_state)
                phydev->adjust_state(phydev->attached_dev);

        switch(phydev->state) {
                case PHY_DOWN:
                case PHY_STARTING:
                case PHY_READY:
                case PHY_PENDING:
                        break;
                case PHY_UP:
                        needs_aneg = 1;

                        phydev->link_timeout = PHY_AN_TIMEOUT;

                        break;
                case PHY_AN:
                        err = phy_read_status(phydev);

                        if (err < 0)
                                break;

                        /* If the link is down, give up on
                         * negotiation for now */
                        if (!phydev->link) {
                                phydev->state = PHY_NOLINK;
                                netif_carrier_off(phydev->attached_dev);
                                phydev->adjust_link(phydev->attached_dev);
                                break;
                        }

                        /* Check if negotiation is done.  Break
                         * if there's an error */
                        err = phy_aneg_done(phydev);
                        if (err < 0)
                                break;

                        /* If AN is done, we're running */
                        if (err > 0) {
                                phydev->state = PHY_RUNNING;
                                netif_carrier_on(phydev->attached_dev);
                                phydev->adjust_link(phydev->attached_dev);

                        } else if (0 == phydev->link_timeout--) {
                                int idx;

                                needs_aneg = 1;
                                /* If we have the magic_aneg bit,
                                 * we try again */
                                if (phydev->drv->flags & PHY_HAS_MAGICANEG)
                                        break;

                                /* The timer expired, and we still
                                 * don't have a setting, so we try
                                 * forcing it until we find one that
                                 * works, starting from the fastest speed,
                                 * and working our way down */
                                idx = phy_find_valid(0, phydev->supported);

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

                                phydev->autoneg = AUTONEG_DISABLE;

                                pr_info("Trying %d/%s\n", phydev->speed,
                                                DUPLEX_FULL ==
                                                phydev->duplex ?
                                                "FULL" : "HALF");
                        }
                        break;
                case PHY_NOLINK:
                        err = phy_read_status(phydev);

                        if (err)
                                break;

                        if (phydev->link) {
                                phydev->state = PHY_RUNNING;
                                netif_carrier_on(phydev->attached_dev);
                                phydev->adjust_link(phydev->attached_dev);
                        }
                        break;
                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--) {
                                        phy_force_reduction(phydev);
                                        needs_aneg = 1;
                                }
                        }

                        phydev->adjust_link(phydev->attached_dev);
                        break;
                case PHY_RUNNING:
                        /* Only register a CHANGE if we are
                         * polling */
                        if (PHY_POLL == phydev->irq)
                                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_POLL != phydev->irq)
                                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);
                        }
                        break;
                case PHY_RESUMING:

                        err = phy_clear_interrupt(phydev);

                        if (err)
                                break;

                        err = phy_config_interrupt(phydev,
                                        PHY_INTERRUPT_ENABLED);

                        if (err)
                                break;

                        if (AUTONEG_ENABLE == phydev->autoneg) {
                                err = phy_aneg_done(phydev);
                                if (err < 0)
                                        break;

                                /* err > 0 if AN is done.
                                 * Otherwise, it's 0, and we're
                                 * still waiting for AN */
                                if (err > 0) {
                                        phydev->state = PHY_RUNNING;
                                } else {
                                        phydev->state = PHY_AN;
                                        phydev->link_timeout = PHY_AN_TIMEOUT;
                                }
                        } else
                                phydev->state = PHY_RUNNING;
                        break;
        }

        mutex_unlock(&phydev->lock);

        if (needs_aneg)
                err = phy_start_aneg(phydev);

        if (err < 0)
                phy_error(phydev);

        mod_timer(&phydev->phy_timer, jiffies + PHY_STATE_TIME * HZ);
}

/* PHY timer which schedules the state machine work */
static void phy_timer(unsigned long data)
{
        struct phy_device *phydev = (struct phy_device *)data;

        /*
         * PHY I/O operations can potentially sleep so we ensure that
         * it's done from a process context
         */
        schedule_work(&phydev->state_queue);
}