/*
 * drivers/net/phy/mdio_bus.c
 *
 * MDIO Bus interface
 *
 * Author: Andy Fleming
 *
 * Copyright (c) 2004 Freescale Semiconductor, Inc.
 *
 * 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/device.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/phy.h>

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

/**
 * mdiobus_alloc - allocate a mii_bus structure
 *
 * Description: called by a bus driver to allocate an mii_bus
 * structure to fill in.
 */
struct mii_bus *mdiobus_alloc(void)
{
        struct mii_bus *bus;

        bus = kzalloc(sizeof(*bus), GFP_KERNEL);
        if (bus != NULL)
                bus->state = MDIOBUS_ALLOCATED;

        return bus;
}
EXPORT_SYMBOL(mdiobus_alloc);

/**
 * mdiobus_release - mii_bus device release callback
 * @d: the target struct device that contains the mii_bus
 *
 * Description: called when the last reference to an mii_bus is
 * dropped, to free the underlying memory.
 */
static void mdiobus_release(struct device *d)
{
        struct mii_bus *bus = to_mii_bus(d);
        BUG_ON(bus->state != MDIOBUS_RELEASED &&
               /* for compatibility with error handling in drivers */
               bus->state != MDIOBUS_ALLOCATED);
        kfree(bus);
}

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

/**
 * mdiobus_register - bring up all the PHYs on a given bus and attach them to bus
 * @bus: target mii_bus
 *
 * Description: Called by a bus driver to bring up all the PHYs
 *   on a given bus, and attach them to the bus.
 *
 * Returns 0 on success or < 0 on error.
 */
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;
        bus->dev.groups = NULL;
        dev_set_name(&bus->dev, "%s", bus->id);

        err = device_register(&bus->dev);
        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);

        for (i = 0; i < PHY_MAX_ADDR; i++) {
                if ((bus->phy_mask & (1 << i)) == 0) {
                        struct phy_device *phydev;

                        phydev = mdiobus_scan(bus, i);
                        if (IS_ERR(phydev)) {
                                err = PTR_ERR(phydev);
                                goto error;
                        }
                }
        }

        bus->state = MDIOBUS_REGISTERED;
        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);

void mdiobus_unregister(struct mii_bus *bus)
{
        int i;

        BUG_ON(bus->state != MDIOBUS_REGISTERED);
        bus->state = MDIOBUS_UNREGISTERED;

        device_del(&bus->dev);
        for (i = 0; i < PHY_MAX_ADDR; i++) {
                if (bus->phy_map[i])
                        device_unregister(&bus->phy_map[i]->dev);
                bus->phy_map[i] = NULL;
        }
}
EXPORT_SYMBOL(mdiobus_unregister);

/**
 * mdiobus_free - free a struct mii_bus
 * @bus: mii_bus to free
 *
 * This function releases the reference to the underlying device
 * object in the mii_bus.  If this is the last reference, the mii_bus
 * will be freed.
 */
void mdiobus_free(struct mii_bus *bus)
{
        /*
         * For compatibility with error handling in drivers.
         */
        if (bus->state == MDIOBUS_ALLOCATED) {
                kfree(bus);
                return;
        }

        BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
        bus->state = MDIOBUS_RELEASED;

        put_device(&bus->dev);
}
EXPORT_SYMBOL(mdiobus_free);

struct phy_device *mdiobus_scan(struct mii_bus *bus, int addr)
{
        struct phy_device *phydev;
        int err;

        phydev = get_phy_device(bus, addr);
        if (IS_ERR(phydev) || phydev == NULL)
                return phydev;

        err = phy_device_register(phydev);
        if (err) {
                phy_device_free(phydev);
                return NULL;
        }

        return phydev;
}
EXPORT_SYMBOL(mdiobus_scan);

/**
 * mdiobus_read - Convenience function for reading a given MII mgmt register
 * @bus: the mii_bus struct
 * @addr: the phy address
 * @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 mdiobus_read(struct mii_bus *bus, int addr, u32 regnum)
{
        int retval;

        BUG_ON(in_interrupt());

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

        return retval;
}
EXPORT_SYMBOL(mdiobus_read);

/**
 * mdiobus_write - Convenience function for writing a given MII mgmt register
 * @bus: the mii_bus struct
 * @addr: the phy address
 * @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 mdiobus_write(struct mii_bus *bus, int addr, u32 regnum, u16 val)
{
        int err;

        BUG_ON(in_interrupt());

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

        return err;
}
EXPORT_SYMBOL(mdiobus_write);

/**
 * mdio_bus_match - determine if given PHY driver supports the given PHY device
 * @dev: target PHY device
 * @drv: given PHY driver
 *
 * Description: Given a PHY device, and a PHY driver, return 1 if
 *   the driver supports the device.  Otherwise, return 0.
 */
static int mdio_bus_match(struct device *dev, struct device_driver *drv)
{
        struct phy_device *phydev = to_phy_device(dev);
        struct phy_driver *phydrv = to_phy_driver(drv);

        return ((phydrv->phy_id & phydrv->phy_id_mask) ==
                (phydev->phy_id & phydrv->phy_id_mask));
}

#ifdef CONFIG_PM

static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
{
        struct device_driver *drv = phydev->dev.driver;
        struct phy_driver *phydrv = to_phy_driver(drv);
        struct net_device *netdev = phydev->attached_dev;

        if (!drv || !phydrv->suspend)
                return false;

        /* PHY not attached? May suspend. */
        if (!netdev)
                return true;

        /*
         * Don't suspend PHY if the attched netdev parent may wakeup.
         * The parent may point to a PCI device, as in tg3 driver.
         */
        if (netdev->dev.parent && device_may_wakeup(netdev->dev.parent))
                return false;

        /*
         * Also don't suspend PHY if the netdev itself may wakeup. This
         * is the case for devices w/o underlaying pwr. mgmt. aware bus,
         * e.g. SoC devices.
         */
        if (device_may_wakeup(&netdev->dev))
                return false;

        return true;
}

static int mdio_bus_suspend(struct device *dev)
{
        struct phy_driver *phydrv = to_phy_driver(dev->driver);
        struct phy_device *phydev = to_phy_device(dev);

        /*
         * We must stop the state machine manually, otherwise it stops out of
         * control, possibly with the phydev->lock held. Upon resume, netdev
         * may call phy routines that try to grab the same lock, and that may
         * lead to a deadlock.
         */
        if (phydev->attached_dev && phydev->adjust_link)
                phy_stop_machine(phydev);

        if (!mdio_bus_phy_may_suspend(phydev))
                return 0;

        return phydrv->suspend(phydev);
}

static int mdio_bus_resume(struct device *dev)
{
        struct phy_driver *phydrv = to_phy_driver(dev->driver);
        struct phy_device *phydev = to_phy_device(dev);
        int ret;

        if (!mdio_bus_phy_may_suspend(phydev))
                goto no_resume;

        ret = phydrv->resume(phydev);
        if (ret < 0)
                return ret;

no_resume:
        if (phydev->attached_dev && phydev->adjust_link)
                phy_start_machine(phydev, NULL);

        return 0;
}

static int mdio_bus_restore(struct device *dev)
{
        struct phy_device *phydev = to_phy_device(dev);
        struct net_device *netdev = phydev->attached_dev;
        int ret;

        if (!netdev)
                return 0;

        ret = phy_init_hw(phydev);
        if (ret < 0)
                return ret;

        /* The PHY needs to renegotiate. */
        phydev->link = 0;
        phydev->state = PHY_UP;

        phy_start_machine(phydev, NULL);

        return 0;
}

static struct dev_pm_ops mdio_bus_pm_ops = {
        .suspend = mdio_bus_suspend,
        .resume = mdio_bus_resume,
        .freeze = mdio_bus_suspend,
        .thaw = mdio_bus_resume,
        .restore = mdio_bus_restore,
};

#define MDIO_BUS_PM_OPS (&mdio_bus_pm_ops)

#else

#define MDIO_BUS_PM_OPS NULL

#endif /* CONFIG_PM */

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

int __init mdio_bus_init(void)
{
        int ret;

        ret = class_register(&mdio_bus_class);
        if (!ret) {
                ret = bus_register(&mdio_bus_type);
                if (ret)
                        class_unregister(&mdio_bus_class);
        }

        return ret;
}

void mdio_bus_exit(void)
{
        class_unregister(&mdio_bus_class);
        bus_unregister(&mdio_bus_type);
}