/* 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.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/interrupt.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 <linux/mdio.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/atomic.h>

#include <asm/irq.h>

static const char *phy_speed_to_str(int speed)
{
        switch (speed) {
        case SPEED_10:
                return "10Mbps";
        case SPEED_100:
                return "100Mbps";
        case SPEED_1000:
                return "1Gbps";
        case SPEED_2500:
                return "2.5Gbps";
        case SPEED_10000:
                return "10Gbps";
        case SPEED_UNKNOWN:
                return "Unknown";
        default:
                return "Unsupported (update phy.c)";
        }
}

#define PHY_STATE_STR(_state)                   \
        case PHY_##_state:                      \
                return __stringify(_state);     \

static const char *phy_state_to_str(enum phy_state st)
{
        switch (st) {
        PHY_STATE_STR(DOWN)
        PHY_STATE_STR(STARTING)
        PHY_STATE_STR(READY)
        PHY_STATE_STR(PENDING)
        PHY_STATE_STR(UP)
        PHY_STATE_STR(AN)
        PHY_STATE_STR(RUNNING)
        PHY_STATE_STR(NOLINK)
        PHY_STATE_STR(FORCING)
        PHY_STATE_STR(CHANGELINK)
        PHY_STATE_STR(HALTED)
        PHY_STATE_STR(RESUMING)
        }

        return NULL;
}


/**
 * 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)
{
        if (phydev->link) {
                netdev_info(phydev->attached_dev,
                        "Link is Up - %s/%s - flow control %s\n",
                        phy_speed_to_str(phydev->speed),
                        DUPLEX_FULL == phydev->duplex ? "Full" : "Half",
                        phydev->pause ? "rx/tx" : "off");
        } else  {
                netdev_info(phydev->attached_dev, "Link is Down\n");
        }
}
EXPORT_SYMBOL(phy_print_status);

/**
 * 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 or < 0 on error.
 */
static int phy_clear_interrupt(struct phy_device *phydev)
{
        if (phydev->drv->ack_interrupt)
                return phydev->drv->ack_interrupt(phydev);

        return 0;
}

/**
 * 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 or < 0 on error.
 */
static int phy_config_interrupt(struct phy_device *phydev, u32 interrupts)
{
        phydev->interrupts = interrupts;
        if (phydev->drv->config_intr)
                return phydev->drv->config_intr(phydev);

        return 0;
}


/**
 * phy_aneg_done - return auto-negotiation status
 * @phydev: target phy_device struct
 *
 * Description: Return the auto-negotiation status from this @phydev
 * Returns > 0 on success or < 0 on error. 0 means that auto-negotiation
 * is still pending.
 */
static inline int phy_aneg_done(struct phy_device *phydev)
{
        if (phydev->drv->aneg_done)
                return phydev->drv->aneg_done(phydev);

        return genphy_aneg_done(phydev);
}

/* 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 = SPEED_10000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_10000baseKR_Full,
        },
        {
                .speed = SPEED_10000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_10000baseKX4_Full,
        },
        {
                .speed = SPEED_10000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_10000baseT_Full,
        },
        {
                .speed = SPEED_2500,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_2500baseX_Full,
        },
        {
                .speed = SPEED_1000,
                .duplex = DUPLEX_FULL,
                .setting = SUPPORTED_1000baseKX_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 unsigned int phy_find_setting(int speed, int duplex)
{
        unsigned 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 unsigned int phy_find_valid(unsigned 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_check_valid - check if there is a valid PHY setting which matches
 *                   speed, duplex, and feature mask
 * @speed: speed to match
 * @duplex: duplex to match
 * @features: A mask of the valid settings
 *
 * Description: Returns true if there is a valid setting, false otherwise.
 */
static inline bool phy_check_valid(int speed, int duplex, u32 features)
{
        unsigned int idx;

        idx = phy_find_valid(phy_find_setting(speed, duplex), features);

        return settings[idx].speed == speed && settings[idx].duplex == duplex &&
                (settings[idx].setting & features);
}

/**
 * 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.
 */
static void phy_sanitize_settings(struct phy_device *phydev)
{
        u32 features = phydev->supported;
        unsigned 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;
}

/**
 * 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)
{
        u32 speed = ethtool_cmd_speed(cmd);

        if (cmd->phy_address != phydev->mdio.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 &&
            ((speed != SPEED_1000 &&
              speed != SPEED_100 &&
              speed != SPEED_10) ||
             (cmd->duplex != DUPLEX_HALF &&
              cmd->duplex != DUPLEX_FULL)))
                return -EINVAL;

        phydev->autoneg = cmd->autoneg;

        phydev->speed = speed;

        phydev->advertising = cmd->advertising;

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

        phydev->duplex = cmd->duplex;

        phydev->mdix = cmd->eth_tp_mdix_ctrl;

        /* 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->lp_advertising = phydev->lp_advertising;

        ethtool_cmd_speed_set(cmd, phydev->speed);
        cmd->duplex = phydev->duplex;
        if (phydev->interface == PHY_INTERFACE_MODE_MOCA)
                cmd->port = PORT_BNC;
        else
                cmd->port = PORT_MII;
        cmd->phy_address = phydev->mdio.addr;
        cmd->transceiver = phy_is_internal(phydev) ?
                XCVR_INTERNAL : XCVR_EXTERNAL;
        cmd->autoneg = phydev->autoneg;
        cmd->eth_tp_mdix_ctrl = phydev->mdix;

        return 0;
}
EXPORT_SYMBOL(phy_ethtool_gset);

/**
 * phy_mii_ioctl - generic PHY MII ioctl interface
 * @phydev: the phy_device struct
 * @ifr: &struct ifreq for socket ioctl's
 * @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 ifreq *ifr, int cmd)
{
        struct mii_ioctl_data *mii_data = if_mii(ifr);
        u16 val = mii_data->val_in;
        bool change_autoneg = false;

        switch (cmd) {
        case SIOCGMIIPHY:
                mii_data->phy_id = phydev->mdio.addr;
                /* fall through */

        case SIOCGMIIREG:
                mii_data->val_out = mdiobus_read(phydev->mdio.bus,
                                                 mii_data->phy_id,
                                                 mii_data->reg_num);
                return 0;

        case SIOCSMIIREG:
                if (mii_data->phy_id == phydev->mdio.addr) {
                        switch (mii_data->reg_num) {
                        case MII_BMCR:
                                if ((val & (BMCR_RESET | BMCR_ANENABLE)) == 0) {
                                        if (phydev->autoneg == AUTONEG_ENABLE)
                                                change_autoneg = true;
                                        phydev->autoneg = AUTONEG_DISABLE;
                                        if (val & BMCR_FULLDPLX)
                                                phydev->duplex = DUPLEX_FULL;
                                        else
                                                phydev->duplex = DUPLEX_HALF;
                                        if (val & BMCR_SPEED1000)
                                                phydev->speed = SPEED_1000;
                                        else if (val & BMCR_SPEED100)
                                                phydev->speed = SPEED_100;
                                        else phydev->speed = SPEED_10;
                                }
                                else {
                                        if (phydev->autoneg == AUTONEG_DISABLE)
                                                change_autoneg = true;
                                        phydev->autoneg = AUTONEG_ENABLE;
                                }
                                break;
                        case MII_ADVERTISE:
                                phydev->advertising = mii_adv_to_ethtool_adv_t(val);
                                change_autoneg = true;
                                break;
                        default:
                                /* do nothing */
                                break;
                        }
                }

                mdiobus_write(phydev->mdio.bus, mii_data->phy_id,
                              mii_data->reg_num, val);

                if (mii_data->phy_id == phydev->mdio.addr &&
                    mii_data->reg_num == MII_BMCR &&
                    val & BMCR_RESET)
                        return phy_init_hw(phydev);

                if (change_autoneg)
                        return phy_start_aneg(phydev);

                return 0;

        case SIOCSHWTSTAMP:
                if (phydev->drv->hwtstamp)
                        return phydev->drv->hwtstamp(phydev, ifr);
                /* fall through */

        default:
                return -EOPNOTSUPP;
        }
}
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);

        /* Invalidate LP advertising flags */
        phydev->lp_advertising = 0;

        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);

/**
 * phy_start_machine - start PHY state machine tracking
 * @phydev: the phy_device struct
 *
 * 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 maintain your own state machine,
 *   do not call this function.
 */
void phy_start_machine(struct phy_device *phydev)
{
        queue_delayed_work(system_power_efficient_wq, &phydev->state_queue, 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)
{
        cancel_delayed_work_sync(&phydev->state_queue);

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

/**
 * 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.
 */
static 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);

        queue_work(system_power_efficient_wq, &phydev->phy_queue);

        return IRQ_HANDLED;
}

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

        if (err < 0)
                return err;

        return phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED);
}

/**
 * phy_disable_interrupts - Disable the PHY interrupts from the PHY side
 * @phydev: target phy_device struct
 */
static 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;
}

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

        return phy_enable_interrupts(phydev);
}
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 = 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
 */
void phy_change(struct work_struct *work)
{
        struct phy_device *phydev =
                container_of(work, struct phy_device, phy_queue);

        if (phy_interrupt_is_valid(phydev)) {
                if (phydev->drv->did_interrupt &&
                    !phydev->drv->did_interrupt(phydev))
                        goto ignore;

                if (phy_disable_interrupts(phydev))
                        goto phy_err;
        }

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

        if (phy_interrupt_is_valid(phydev)) {
                atomic_dec(&phydev->irq_disable);
                enable_irq(phydev->irq);

                /* Reenable interrupts */
                if (PHY_HALTED != phydev->state &&
                    phy_config_interrupt(phydev, PHY_INTERRUPT_ENABLED))
                        goto irq_enable_err;
        }

        /* reschedule state queue work to run as soon as possible */
        cancel_delayed_work_sync(&phydev->state_queue);
        queue_delayed_work(system_power_efficient_wq, &phydev->state_queue, 0);
        return;

ignore:
        atomic_dec(&phydev->irq_disable);
        enable_irq(phydev->irq);
        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 (phy_interrupt_is_valid(phydev)) {
                /* 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.
         */
}
EXPORT_SYMBOL(phy_stop);

/**
 * 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)
{
        bool do_resume = false;
        int err = 0;

        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:
                /* make sure interrupts are re-enabled for the PHY */
                if (phydev->irq != PHY_POLL) {
                        err = phy_enable_interrupts(phydev);
                        if (err < 0)
                                break;
                }

                phydev->state = PHY_RESUMING;
                do_resume = true;
                break;
        default:
                break;
        }
        mutex_unlock(&phydev->lock);

        /* if phy was suspended, bring the physical link up again */
        if (do_resume)
                phy_resume(phydev);
}
EXPORT_SYMBOL(phy_start);

/**
 * phy_state_machine - Handle the state machine
 * @work: work_struct that describes the work to be done
 */
void phy_state_machine(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct phy_device *phydev =
                        container_of(dwork, struct phy_device, state_queue);
        bool needs_aneg = false, do_suspend = false;
        enum phy_state old_state;
        int err = 0;
        int old_link;

        mutex_lock(&phydev->lock);

        old_state = phydev->state;

        if (phydev->drv->link_change_notify)
                phydev->drv->link_change_notify(phydev);

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

                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--)
                        needs_aneg = true;
                break;
        case PHY_NOLINK:
                if (phy_interrupt_is_valid(phydev))
                        break;

                err = phy_read_status(phydev);
                if (err)
                        break;

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

                                if (!err) {
                                        phydev->state = PHY_AN;
                                        phydev->link_timeout = PHY_AN_TIMEOUT;
                                        break;
                                }
                        }
                        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--)
                                needs_aneg = true;
                }

                phydev->adjust_link(phydev->attached_dev);
                break;
        case PHY_RUNNING:
                /* Only register a CHANGE if we are polling and link changed
                 * since latest checking.
                 */
                if (phydev->irq == PHY_POLL) {
                        old_link = phydev->link;
                        err = phy_read_status(phydev);
                        if (err)
                                break;

                        if (old_link != phydev->link)
                                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;
        case PHY_RESUMING:
                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) {
                                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;
                                }
                                phydev->adjust_link(phydev->attached_dev);
                        } else {
                                phydev->state = PHY_AN;
                                phydev->link_timeout = PHY_AN_TIMEOUT;
                        }
                } else {
                        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;
                        }
                        phydev->adjust_link(phydev->attached_dev);
                }
                break;
        }

        mutex_unlock(&phydev->lock);

        if (needs_aneg)
                err = phy_start_aneg(phydev);
        else if (do_suspend)
                phy_suspend(phydev);

        if (err < 0)
                phy_error(phydev);

        phydev_dbg(phydev, "PHY state change %s -> %s\n",
                   phy_state_to_str(old_state),
                   phy_state_to_str(phydev->state));

        /* Only re-schedule a PHY state machine change if we are polling the
         * PHY, if PHY_IGNORE_INTERRUPT is set, then we will be moving
         * between states from phy_mac_interrupt()
         */
        if (phydev->irq == PHY_POLL)
                queue_delayed_work(system_power_efficient_wq, &phydev->state_queue,
                                   PHY_STATE_TIME * HZ);
}

void phy_mac_interrupt(struct phy_device *phydev, int new_link)
{
        phydev->link = new_link;

        /* Trigger a state machine change */
        queue_work(system_power_efficient_wq, &phydev->phy_queue);
}
EXPORT_SYMBOL(phy_mac_interrupt);

static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,
                                    int addr)
{
        /* Write the desired MMD Devad */
        bus->write(bus, addr, MII_MMD_CTRL, devad);

        /* Write the desired MMD register address */
        bus->write(bus, addr, MII_MMD_DATA, prtad);

        /* Select the Function : DATA with no post increment */
        bus->write(bus, addr, MII_MMD_CTRL, (devad | MII_MMD_CTRL_NOINCR));
}

/**
 * phy_read_mmd_indirect - reads data from the MMD registers
 * @phydev: The PHY device bus
 * @prtad: MMD Address
 * @devad: MMD DEVAD
 *
 * Description: it reads data from the MMD registers (clause 22 to access to
 * clause 45) of the specified phy address.
 * To read these register we have:
 * 1) Write reg 13 // DEVAD
 * 2) Write reg 14 // MMD Address
 * 3) Write reg 13 // MMD Data Command for MMD DEVAD
 * 3) Read  reg 14 // Read MMD data
 */
int phy_read_mmd_indirect(struct phy_device *phydev, int prtad, int devad)
{
        struct phy_driver *phydrv = phydev->drv;
        int addr = phydev->mdio.addr;
        int value = -1;

        if (!phydrv->read_mmd_indirect) {
                struct mii_bus *bus = phydev->mdio.bus;

                mutex_lock(&bus->mdio_lock);
                mmd_phy_indirect(bus, prtad, devad, addr);

                /* Read the content of the MMD's selected register */
                value = bus->read(bus, addr, MII_MMD_DATA);
                mutex_unlock(&bus->mdio_lock);
        } else {
                value = phydrv->read_mmd_indirect(phydev, prtad, devad, addr);
        }
        return value;
}
EXPORT_SYMBOL(phy_read_mmd_indirect);

/**
 * phy_write_mmd_indirect - writes data to the MMD registers
 * @phydev: The PHY device
 * @prtad: MMD Address
 * @devad: MMD DEVAD
 * @data: data to write in the MMD register
 *
 * Description: Write data from the MMD registers of the specified
 * phy address.
 * To write these register we have:
 * 1) Write reg 13 // DEVAD
 * 2) Write reg 14 // MMD Address
 * 3) Write reg 13 // MMD Data Command for MMD DEVAD
 * 3) Write reg 14 // Write MMD data
 */
void phy_write_mmd_indirect(struct phy_device *phydev, int prtad,
                                   int devad, u32 data)
{
        struct phy_driver *phydrv = phydev->drv;
        int addr = phydev->mdio.addr;

        if (!phydrv->write_mmd_indirect) {
                struct mii_bus *bus = phydev->mdio.bus;

                mutex_lock(&bus->mdio_lock);
                mmd_phy_indirect(bus, prtad, devad, addr);

                /* Write the data into MMD's selected register */
                bus->write(bus, addr, MII_MMD_DATA, data);
                mutex_unlock(&bus->mdio_lock);
        } else {
                phydrv->write_mmd_indirect(phydev, prtad, devad, addr, data);
        }
}
EXPORT_SYMBOL(phy_write_mmd_indirect);

/**
 * phy_init_eee - init and check the EEE feature
 * @phydev: target phy_device struct
 * @clk_stop_enable: PHY may stop the clock during LPI
 *
 * Description: it checks if the Energy-Efficient Ethernet (EEE)
 * is supported by looking at the MMD registers 3.20 and 7.60/61
 * and it programs the MMD register 3.0 setting the "Clock stop enable"
 * bit if required.
 */
int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable)
{
        /* According to 802.3az,the EEE is supported only in full duplex-mode.
         * Also EEE feature is active when core is operating with MII, GMII
         * or RGMII (all kinds). Internal PHYs are also allowed to proceed and
         * should return an error if they do not support EEE.
         */
        if ((phydev->duplex == DUPLEX_FULL) &&
            ((phydev->interface == PHY_INTERFACE_MODE_MII) ||
            (phydev->interface == PHY_INTERFACE_MODE_GMII) ||
             phy_interface_is_rgmii(phydev) ||
             phy_is_internal(phydev))) {
                int eee_lp, eee_cap, eee_adv;
                u32 lp, cap, adv;
                int status;

                /* Read phy status to properly get the right settings */
                status = phy_read_status(phydev);
                if (status)
                        return status;

                /* First check if the EEE ability is supported */
                eee_cap = phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_ABLE,
                                                MDIO_MMD_PCS);
                if (eee_cap <= 0)
                        goto eee_exit_err;

                cap = mmd_eee_cap_to_ethtool_sup_t(eee_cap);
                if (!cap)
                        goto eee_exit_err;

                /* Check which link settings negotiated and verify it in
                 * the EEE advertising registers.
                 */
                eee_lp = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_LPABLE,
                                               MDIO_MMD_AN);
                if (eee_lp <= 0)
                        goto eee_exit_err;

                eee_adv = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_ADV,
                                                MDIO_MMD_AN);
                if (eee_adv <= 0)
                        goto eee_exit_err;

                adv = mmd_eee_adv_to_ethtool_adv_t(eee_adv);
                lp = mmd_eee_adv_to_ethtool_adv_t(eee_lp);
                if (!phy_check_valid(phydev->speed, phydev->duplex, lp & adv))
                        goto eee_exit_err;

                if (clk_stop_enable) {
                        /* Configure the PHY to stop receiving xMII
                         * clock while it is signaling LPI.
                         */
                        int val = phy_read_mmd_indirect(phydev, MDIO_CTRL1,
                                                        MDIO_MMD_PCS);
                        if (val < 0)
                                return val;

                        val |= MDIO_PCS_CTRL1_CLKSTOP_EN;
                        phy_write_mmd_indirect(phydev, MDIO_CTRL1,
                                               MDIO_MMD_PCS, val);
                }

                return 0; /* EEE supported */
        }
eee_exit_err:
        return -EPROTONOSUPPORT;
}
EXPORT_SYMBOL(phy_init_eee);

/**
 * phy_get_eee_err - report the EEE wake error count
 * @phydev: target phy_device struct
 *
 * Description: it is to report the number of time where the PHY
 * failed to complete its normal wake sequence.
 */
int phy_get_eee_err(struct phy_device *phydev)
{
        return phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_WK_ERR, MDIO_MMD_PCS);
}
EXPORT_SYMBOL(phy_get_eee_err);

/**
 * phy_ethtool_get_eee - get EEE supported and status
 * @phydev: target phy_device struct
 * @data: ethtool_eee data
 *
 * Description: it reportes the Supported/Advertisement/LP Advertisement
 * capabilities.
 */
int phy_ethtool_get_eee(struct phy_device *phydev, struct ethtool_eee *data)
{
        int val;

        /* Get Supported EEE */
        val = phy_read_mmd_indirect(phydev, MDIO_PCS_EEE_ABLE, MDIO_MMD_PCS);
        if (val < 0)
                return val;
        data->supported = mmd_eee_cap_to_ethtool_sup_t(val);

        /* Get advertisement EEE */
        val = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN);
        if (val < 0)
                return val;
        data->advertised = mmd_eee_adv_to_ethtool_adv_t(val);

        /* Get LP advertisement EEE */
        val = phy_read_mmd_indirect(phydev, MDIO_AN_EEE_LPABLE, MDIO_MMD_AN);
        if (val < 0)
                return val;
        data->lp_advertised = mmd_eee_adv_to_ethtool_adv_t(val);

        return 0;
}
EXPORT_SYMBOL(phy_ethtool_get_eee);

/**
 * phy_ethtool_set_eee - set EEE supported and status
 * @phydev: target phy_device struct
 * @data: ethtool_eee data
 *
 * Description: it is to program the Advertisement EEE register.
 */
int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data)
{
        int val = ethtool_adv_to_mmd_eee_adv_t(data->advertised);

        phy_write_mmd_indirect(phydev, MDIO_AN_EEE_ADV, MDIO_MMD_AN, val);

        return 0;
}
EXPORT_SYMBOL(phy_ethtool_set_eee);

int phy_ethtool_set_wol(struct phy_device *phydev, struct ethtool_wolinfo *wol)
{
        if (phydev->drv->set_wol)
                return phydev->drv->set_wol(phydev, wol);

        return -EOPNOTSUPP;
}
EXPORT_SYMBOL(phy_ethtool_set_wol);

void phy_ethtool_get_wol(struct phy_device *phydev, struct ethtool_wolinfo *wol)
{
        if (phydev->drv->get_wol)
                phydev->drv->get_wol(phydev, wol);
}
EXPORT_SYMBOL(phy_ethtool_get_wol);