xref: /openbmc/linux/drivers/net/phy/phy_device.c (revision c4ee0af3)

/*
 * drivers/net/phy/phy_device.c
 *
 * Framework for finding and configuring PHYs.
 * Also contains generic PHY driver
 *
 * 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.
 *
 */

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

MODULE_DESCRIPTION("PHY library");
MODULE_AUTHOR("Andy Fleming");
MODULE_LICENSE("GPL");

void phy_device_free(struct phy_device *phydev)
{
	put_device(&phydev->dev);
}
EXPORT_SYMBOL(phy_device_free);

static void phy_device_release(struct device *dev)
{
	kfree(to_phy_device(dev));
}

static struct phy_driver genphy_driver;
extern int mdio_bus_init(void);
extern void mdio_bus_exit(void);

static LIST_HEAD(phy_fixup_list);
static DEFINE_MUTEX(phy_fixup_lock);

static int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
			     u32 flags, phy_interface_t interface);

/*
 * Creates a new phy_fixup and adds it to the list
 * @bus_id: A string which matches phydev->dev.bus_id (or PHY_ANY_ID)
 * @phy_uid: Used to match against phydev->phy_id (the UID of the PHY)
 * 	It can also be PHY_ANY_UID
 * @phy_uid_mask: Applied to phydev->phy_id and fixup->phy_uid before
 * 	comparison
 * @run: The actual code to be run when a matching PHY is found
 */
int phy_register_fixup(const char *bus_id, u32 phy_uid, u32 phy_uid_mask,
		int (*run)(struct phy_device *))
{
	struct phy_fixup *fixup;

	fixup = kzalloc(sizeof(struct phy_fixup), GFP_KERNEL);
	if (!fixup)
		return -ENOMEM;

	strlcpy(fixup->bus_id, bus_id, sizeof(fixup->bus_id));
	fixup->phy_uid = phy_uid;
	fixup->phy_uid_mask = phy_uid_mask;
	fixup->run = run;

	mutex_lock(&phy_fixup_lock);
	list_add_tail(&fixup->list, &phy_fixup_list);
	mutex_unlock(&phy_fixup_lock);

	return 0;
}
EXPORT_SYMBOL(phy_register_fixup);

/* Registers a fixup to be run on any PHY with the UID in phy_uid */
int phy_register_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask,
		int (*run)(struct phy_device *))
{
	return phy_register_fixup(PHY_ANY_ID, phy_uid, phy_uid_mask, run);
}
EXPORT_SYMBOL(phy_register_fixup_for_uid);

/* Registers a fixup to be run on the PHY with id string bus_id */
int phy_register_fixup_for_id(const char *bus_id,
		int (*run)(struct phy_device *))
{
	return phy_register_fixup(bus_id, PHY_ANY_UID, 0xffffffff, run);
}
EXPORT_SYMBOL(phy_register_fixup_for_id);

/*
 * Returns 1 if fixup matches phydev in bus_id and phy_uid.
 * Fixups can be set to match any in one or more fields.
 */
static int phy_needs_fixup(struct phy_device *phydev, struct phy_fixup *fixup)
{
	if (strcmp(fixup->bus_id, dev_name(&phydev->dev)) != 0)
		if (strcmp(fixup->bus_id, PHY_ANY_ID) != 0)
			return 0;

	if ((fixup->phy_uid & fixup->phy_uid_mask) !=
			(phydev->phy_id & fixup->phy_uid_mask))
		if (fixup->phy_uid != PHY_ANY_UID)
			return 0;

	return 1;
}

/* Runs any matching fixups for this phydev */
int phy_scan_fixups(struct phy_device *phydev)
{
	struct phy_fixup *fixup;

	mutex_lock(&phy_fixup_lock);
	list_for_each_entry(fixup, &phy_fixup_list, list) {
		if (phy_needs_fixup(phydev, fixup)) {
			int err;

			err = fixup->run(phydev);

			if (err < 0) {
				mutex_unlock(&phy_fixup_lock);
				return err;
			}
		}
	}
	mutex_unlock(&phy_fixup_lock);

	return 0;
}
EXPORT_SYMBOL(phy_scan_fixups);

struct phy_device *phy_device_create(struct mii_bus *bus, int addr, int phy_id,
			bool is_c45, struct phy_c45_device_ids *c45_ids)
{
	struct phy_device *dev;

	/* We allocate the device, and initialize the
	 * default values */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (NULL == dev)
		return (struct phy_device*) PTR_ERR((void*)-ENOMEM);

	dev->dev.release = phy_device_release;

	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->is_c45 = is_c45;
	dev->addr = addr;
	dev->phy_id = phy_id;
	if (c45_ids)
		dev->c45_ids = *c45_ids;
	dev->bus = bus;
	dev->dev.parent = bus->parent;
	dev->dev.bus = &mdio_bus_type;
	dev->irq = bus->irq != NULL ? bus->irq[addr] : PHY_POLL;
	dev_set_name(&dev->dev, PHY_ID_FMT, bus->id, addr);

	dev->state = PHY_DOWN;

	mutex_init(&dev->lock);
	INIT_DELAYED_WORK(&dev->state_queue, phy_state_machine);
	INIT_WORK(&dev->phy_queue, phy_change);

	/* Request the appropriate module unconditionally; don't
	   bother trying to do so only if it isn't already loaded,
	   because that gets complicated. A hotplug event would have
	   done an unconditional modprobe anyway.
	   We don't do normal hotplug because it won't work for MDIO
	   -- because it relies on the device staying around for long
	   enough for the driver to get loaded. With MDIO, the NIC
	   driver will get bored and give up as soon as it finds that
	   there's no driver _already_ loaded. */
	request_module(MDIO_MODULE_PREFIX MDIO_ID_FMT, MDIO_ID_ARGS(phy_id));

	device_initialize(&dev->dev);

	return dev;
}
EXPORT_SYMBOL(phy_device_create);

/**
 * get_phy_c45_ids - reads the specified addr for its 802.3-c45 IDs.
 * @bus: the target MII bus
 * @addr: PHY address on the MII bus
 * @phy_id: where to store the ID retrieved.
 * @c45_ids: where to store the c45 ID information.
 *
 *   If the PHY devices-in-package appears to be valid, it and the
 *   corresponding identifiers are stored in @c45_ids, zero is stored
 *   in @phy_id.  Otherwise 0xffffffff is stored in @phy_id.  Returns
 *   zero on success.
 *
 */
static int get_phy_c45_ids(struct mii_bus *bus, int addr, u32 *phy_id,
			   struct phy_c45_device_ids *c45_ids) {
	int phy_reg;
	int i, reg_addr;
	const int num_ids = ARRAY_SIZE(c45_ids->device_ids);

	/* Find first non-zero Devices In package.  Device
	 * zero is reserved, so don't probe it.
	 */
	for (i = 1;
	     i < num_ids && c45_ids->devices_in_package == 0;
	     i++) {
		reg_addr = MII_ADDR_C45 | i << 16 | 6;
		phy_reg = mdiobus_read(bus, addr, reg_addr);
		if (phy_reg < 0)
			return -EIO;
		c45_ids->devices_in_package = (phy_reg & 0xffff) << 16;

		reg_addr = MII_ADDR_C45 | i << 16 | 5;
		phy_reg = mdiobus_read(bus, addr, reg_addr);
		if (phy_reg < 0)
			return -EIO;
		c45_ids->devices_in_package |= (phy_reg & 0xffff);

		/* If mostly Fs, there is no device there,
		 * let's get out of here.
		 */
		if ((c45_ids->devices_in_package & 0x1fffffff) == 0x1fffffff) {
			*phy_id = 0xffffffff;
			return 0;
		}
	}

	/* Now probe Device Identifiers for each device present. */
	for (i = 1; i < num_ids; i++) {
		if (!(c45_ids->devices_in_package & (1 << i)))
			continue;

		reg_addr = MII_ADDR_C45 | i << 16 | MII_PHYSID1;
		phy_reg = mdiobus_read(bus, addr, reg_addr);
		if (phy_reg < 0)
			return -EIO;
		c45_ids->device_ids[i] = (phy_reg & 0xffff) << 16;

		reg_addr = MII_ADDR_C45 | i << 16 | MII_PHYSID2;
		phy_reg = mdiobus_read(bus, addr, reg_addr);
		if (phy_reg < 0)
			return -EIO;
		c45_ids->device_ids[i] |= (phy_reg & 0xffff);
	}
	*phy_id = 0;
	return 0;
}

/**
 * get_phy_id - reads the specified addr for its ID.
 * @bus: the target MII bus
 * @addr: PHY address on the MII bus
 * @phy_id: where to store the ID retrieved.
 * @is_c45: If true the PHY uses the 802.3 clause 45 protocol
 * @c45_ids: where to store the c45 ID information.
 *
 * Description: In the case of a 802.3-c22 PHY, reads the ID registers
 *   of the PHY at @addr on the @bus, stores it in @phy_id and returns
 *   zero on success.
 *
 *   In the case of a 802.3-c45 PHY, get_phy_c45_ids() is invoked, and
 *   its return value is in turn returned.
 *
 */
static int get_phy_id(struct mii_bus *bus, int addr, u32 *phy_id,
		      bool is_c45, struct phy_c45_device_ids *c45_ids)
{
	int phy_reg;

	if (is_c45)
		return get_phy_c45_ids(bus, addr, phy_id, c45_ids);

	/* Grab the bits from PHYIR1, and put them
	 * in the upper half */
	phy_reg = mdiobus_read(bus, addr, MII_PHYSID1);

	if (phy_reg < 0)
		return -EIO;

	*phy_id = (phy_reg & 0xffff) << 16;

	/* Grab the bits from PHYIR2, and put them in the lower half */
	phy_reg = mdiobus_read(bus, addr, MII_PHYSID2);

	if (phy_reg < 0)
		return -EIO;

	*phy_id |= (phy_reg & 0xffff);

	return 0;
}

/**
 * get_phy_device - reads the specified PHY device and returns its @phy_device struct
 * @bus: the target MII bus
 * @addr: PHY address on the MII bus
 * @is_c45: If true the PHY uses the 802.3 clause 45 protocol
 *
 * Description: Reads the ID registers of the PHY at @addr on the
 *   @bus, then allocates and returns the phy_device to represent it.
 */
struct phy_device *get_phy_device(struct mii_bus *bus, int addr, bool is_c45)
{
	struct phy_c45_device_ids c45_ids = {0};
	struct phy_device *dev = NULL;
	u32 phy_id = 0;
	int r;

	r = get_phy_id(bus, addr, &phy_id, is_c45, &c45_ids);
	if (r)
		return ERR_PTR(r);

	/* If the phy_id is mostly Fs, there is no device there */
	if ((phy_id & 0x1fffffff) == 0x1fffffff)
		return NULL;

	dev = phy_device_create(bus, addr, phy_id, is_c45, &c45_ids);

	return dev;
}
EXPORT_SYMBOL(get_phy_device);

/**
 * phy_device_register - Register the phy device on the MDIO bus
 * @phydev: phy_device structure to be added to the MDIO bus
 */
int phy_device_register(struct phy_device *phydev)
{
	int err;

	/* Don't register a phy if one is already registered at this
	 * address */
	if (phydev->bus->phy_map[phydev->addr])
		return -EINVAL;
	phydev->bus->phy_map[phydev->addr] = phydev;

	/* Run all of the fixups for this PHY */
	phy_scan_fixups(phydev);

	err = device_add(&phydev->dev);
	if (err) {
		pr_err("PHY %d failed to add\n", phydev->addr);
		goto out;
	}

	return 0;

 out:
	phydev->bus->phy_map[phydev->addr] = NULL;
	return err;
}
EXPORT_SYMBOL(phy_device_register);

/**
 * phy_find_first - finds the first PHY device on the bus
 * @bus: the target MII bus
 */
struct phy_device *phy_find_first(struct mii_bus *bus)
{
	int addr;

	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
		if (bus->phy_map[addr])
			return bus->phy_map[addr];
	}
	return NULL;
}
EXPORT_SYMBOL(phy_find_first);

/**
 * phy_prepare_link - prepares the PHY layer to monitor link status
 * @phydev: target phy_device struct
 * @handler: callback function for link status change notifications
 *
 * Description: Tells the PHY infrastructure to handle the
 *   gory details on monitoring link status (whether through
 *   polling or an interrupt), and to call back to the
 *   connected device driver when the link status changes.
 *   If you want to monitor your own link state, don't call
 *   this function.
 */
static void phy_prepare_link(struct phy_device *phydev,
		void (*handler)(struct net_device *))
{
	phydev->adjust_link = handler;
}

/**
 * phy_connect_direct - connect an ethernet device to a specific phy_device
 * @dev: the network device to connect
 * @phydev: the pointer to the phy device
 * @handler: callback function for state change notifications
 * @interface: PHY device's interface
 */
int phy_connect_direct(struct net_device *dev, struct phy_device *phydev,
		       void (*handler)(struct net_device *),
		       phy_interface_t interface)
{
	int rc;

	rc = phy_attach_direct(dev, phydev, phydev->dev_flags, interface);
	if (rc)
		return rc;

	phy_prepare_link(phydev, handler);
	phy_start_machine(phydev, NULL);
	if (phydev->irq > 0)
		phy_start_interrupts(phydev);

	return 0;
}
EXPORT_SYMBOL(phy_connect_direct);

/**
 * phy_connect - connect an ethernet device to a PHY device
 * @dev: the network device to connect
 * @bus_id: the id string of the PHY device to connect
 * @handler: callback function for state change notifications
 * @interface: PHY device's interface
 *
 * Description: Convenience function for connecting ethernet
 *   devices to PHY devices.  The default behavior is for
 *   the PHY infrastructure to handle everything, and only notify
 *   the connected driver when the link status changes.  If you
 *   don't want, or can't use the provided functionality, you may
 *   choose to call only the subset of functions which provide
 *   the desired functionality.
 */
struct phy_device * phy_connect(struct net_device *dev, const char *bus_id,
		void (*handler)(struct net_device *),
		phy_interface_t interface)
{
	struct phy_device *phydev;
	struct device *d;
	int rc;

	/* Search the list of PHY devices on the mdio bus for the
	 * PHY with the requested name */
	d = bus_find_device_by_name(&mdio_bus_type, NULL, bus_id);
	if (!d) {
		pr_err("PHY %s not found\n", bus_id);
		return ERR_PTR(-ENODEV);
	}
	phydev = to_phy_device(d);

	rc = phy_connect_direct(dev, phydev, handler, interface);
	if (rc)
		return ERR_PTR(rc);

	return phydev;
}
EXPORT_SYMBOL(phy_connect);

/**
 * phy_disconnect - disable interrupts, stop state machine, and detach a PHY device
 * @phydev: target phy_device struct
 */
void phy_disconnect(struct phy_device *phydev)
{
	if (phydev->irq > 0)
		phy_stop_interrupts(phydev);

	phy_stop_machine(phydev);

	phydev->adjust_link = NULL;

	phy_detach(phydev);
}
EXPORT_SYMBOL(phy_disconnect);

int phy_init_hw(struct phy_device *phydev)
{
	int ret;

	if (!phydev->drv || !phydev->drv->config_init)
		return 0;

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

	return phydev->drv->config_init(phydev);
}

/**
 * phy_attach_direct - attach a network device to a given PHY device pointer
 * @dev: network device to attach
 * @phydev: Pointer to phy_device to attach
 * @flags: PHY device's dev_flags
 * @interface: PHY device's interface
 *
 * Description: Called by drivers to attach to a particular PHY
 *     device. The phy_device is found, and properly hooked up
 *     to the phy_driver.  If no driver is attached, then the
 *     genphy_driver is used.  The phy_device is given a ptr to
 *     the attaching device, and given a callback for link status
 *     change.  The phy_device is returned to the attaching driver.
 */
static int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
			     u32 flags, phy_interface_t interface)
{
	struct device *d = &phydev->dev;
	int err;

	/* Assume that if there is no driver, that it doesn't
	 * exist, and we should use the genphy driver. */
	if (NULL == d->driver) {
		if (phydev->is_c45) {
			pr_err("No driver for phy %x\n", phydev->phy_id);
			return -ENODEV;
		}

		d->driver = &genphy_driver.driver;

		err = d->driver->probe(d);
		if (err >= 0)
			err = device_bind_driver(d);

		if (err)
			return err;
	}

	if (phydev->attached_dev) {
		dev_err(&dev->dev, "PHY already attached\n");
		return -EBUSY;
	}

	phydev->attached_dev = dev;
	dev->phydev = phydev;

	phydev->dev_flags = flags;

	phydev->interface = interface;

	phydev->state = PHY_READY;

	/* Do initial configuration here, now that
	 * we have certain key parameters
	 * (dev_flags and interface) */
	err = phy_init_hw(phydev);
	if (err)
		phy_detach(phydev);

	return err;
}

/**
 * phy_attach - attach a network device to a particular PHY device
 * @dev: network device to attach
 * @bus_id: Bus ID of PHY device to attach
 * @interface: PHY device's interface
 *
 * Description: Same as phy_attach_direct() except that a PHY bus_id
 *     string is passed instead of a pointer to a struct phy_device.
 */
struct phy_device *phy_attach(struct net_device *dev,
		const char *bus_id, phy_interface_t interface)
{
	struct bus_type *bus = &mdio_bus_type;
	struct phy_device *phydev;
	struct device *d;
	int rc;

	/* Search the list of PHY devices on the mdio bus for the
	 * PHY with the requested name */
	d = bus_find_device_by_name(bus, NULL, bus_id);
	if (!d) {
		pr_err("PHY %s not found\n", bus_id);
		return ERR_PTR(-ENODEV);
	}
	phydev = to_phy_device(d);

	rc = phy_attach_direct(dev, phydev, phydev->dev_flags, interface);
	if (rc)
		return ERR_PTR(rc);

	return phydev;
}
EXPORT_SYMBOL(phy_attach);

/**
 * phy_detach - detach a PHY device from its network device
 * @phydev: target phy_device struct
 */
void phy_detach(struct phy_device *phydev)
{
	phydev->attached_dev->phydev = NULL;
	phydev->attached_dev = NULL;

	/* If the device had no specific driver before (i.e. - it
	 * was using the generic driver), we unbind the device
	 * from the generic driver so that there's a chance a
	 * real driver could be loaded */
	if (phydev->dev.driver == &genphy_driver.driver)
		device_release_driver(&phydev->dev);
}
EXPORT_SYMBOL(phy_detach);


/* Generic PHY support and helper functions */

/**
 * genphy_config_advert - sanitize and advertise auto-negotiation parameters
 * @phydev: target phy_device struct
 *
 * Description: Writes MII_ADVERTISE with the appropriate values,
 *   after sanitizing the values to make sure we only advertise
 *   what is supported.  Returns < 0 on error, 0 if the PHY's advertisement
 *   hasn't changed, and > 0 if it has changed.
 */
static int genphy_config_advert(struct phy_device *phydev)
{
	u32 advertise;
	int oldadv, adv;
	int err, changed = 0;

	/* Only allow advertising what
	 * this PHY supports */
	phydev->advertising &= phydev->supported;
	advertise = phydev->advertising;

	/* Setup standard advertisement */
	oldadv = adv = phy_read(phydev, MII_ADVERTISE);

	if (adv < 0)
		return adv;

	adv &= ~(ADVERTISE_ALL | ADVERTISE_100BASE4 | ADVERTISE_PAUSE_CAP |
		 ADVERTISE_PAUSE_ASYM);
	adv |= ethtool_adv_to_mii_adv_t(advertise);

	if (adv != oldadv) {
		err = phy_write(phydev, MII_ADVERTISE, adv);

		if (err < 0)
			return err;
		changed = 1;
	}

	/* Configure gigabit if it's supported */
	if (phydev->supported & (SUPPORTED_1000baseT_Half |
				SUPPORTED_1000baseT_Full)) {
		oldadv = adv = phy_read(phydev, MII_CTRL1000);

		if (adv < 0)
			return adv;

		adv &= ~(ADVERTISE_1000FULL | ADVERTISE_1000HALF);
		adv |= ethtool_adv_to_mii_ctrl1000_t(advertise);

		if (adv != oldadv) {
			err = phy_write(phydev, MII_CTRL1000, adv);

			if (err < 0)
				return err;
			changed = 1;
		}
	}

	return changed;
}

/**
 * genphy_setup_forced - configures/forces speed/duplex from @phydev
 * @phydev: target phy_device struct
 *
 * Description: Configures MII_BMCR to force speed/duplex
 *   to the values in phydev. Assumes that the values are valid.
 *   Please see phy_sanitize_settings().
 */
int genphy_setup_forced(struct phy_device *phydev)
{
	int err;
	int ctl = 0;

	phydev->pause = phydev->asym_pause = 0;

	if (SPEED_1000 == phydev->speed)
		ctl |= BMCR_SPEED1000;
	else if (SPEED_100 == phydev->speed)
		ctl |= BMCR_SPEED100;

	if (DUPLEX_FULL == phydev->duplex)
		ctl |= BMCR_FULLDPLX;

	err = phy_write(phydev, MII_BMCR, ctl);

	return err;
}
EXPORT_SYMBOL(genphy_setup_forced);

/**
 * genphy_restart_aneg - Enable and Restart Autonegotiation
 * @phydev: target phy_device struct
 */
int genphy_restart_aneg(struct phy_device *phydev)
{
	int ctl;

	ctl = phy_read(phydev, MII_BMCR);

	if (ctl < 0)
		return ctl;

	ctl |= (BMCR_ANENABLE | BMCR_ANRESTART);

	/* Don't isolate the PHY if we're negotiating */
	ctl &= ~(BMCR_ISOLATE);

	ctl = phy_write(phydev, MII_BMCR, ctl);

	return ctl;
}
EXPORT_SYMBOL(genphy_restart_aneg);


/**
 * genphy_config_aneg - restart auto-negotiation or write BMCR
 * @phydev: target phy_device struct
 *
 * Description: If auto-negotiation is enabled, we configure the
 *   advertising, and then restart auto-negotiation.  If it is not
 *   enabled, then we write the BMCR.
 */
int genphy_config_aneg(struct phy_device *phydev)
{
	int result;

	if (AUTONEG_ENABLE != phydev->autoneg)
		return genphy_setup_forced(phydev);

	result = genphy_config_advert(phydev);

	if (result < 0) /* error */
		return result;

	if (result == 0) {
		/* Advertisement hasn't changed, but maybe aneg was never on to
		 * begin with?  Or maybe phy was isolated? */
		int ctl = phy_read(phydev, MII_BMCR);

		if (ctl < 0)
			return ctl;

		if (!(ctl & BMCR_ANENABLE) || (ctl & BMCR_ISOLATE))
			result = 1; /* do restart aneg */
	}

	/* Only restart aneg if we are advertising something different
	 * than we were before.	 */
	if (result > 0)
		result = genphy_restart_aneg(phydev);

	return result;
}
EXPORT_SYMBOL(genphy_config_aneg);

/**
 * genphy_update_link - update link status in @phydev
 * @phydev: target phy_device struct
 *
 * Description: Update the value in phydev->link to reflect the
 *   current link value.  In order to do this, we need to read
 *   the status register twice, keeping the second value.
 */
int genphy_update_link(struct phy_device *phydev)
{
	int status;

	/* Do a fake read */
	status = phy_read(phydev, MII_BMSR);

	if (status < 0)
		return status;

	/* Read link and autonegotiation status */
	status = phy_read(phydev, MII_BMSR);

	if (status < 0)
		return status;

	if ((status & BMSR_LSTATUS) == 0)
		phydev->link = 0;
	else
		phydev->link = 1;

	return 0;
}
EXPORT_SYMBOL(genphy_update_link);

/**
 * genphy_read_status - check the link status and update current link state
 * @phydev: target phy_device struct
 *
 * Description: Check the link, then figure out the current state
 *   by comparing what we advertise with what the link partner
 *   advertises.  Start by checking the gigabit possibilities,
 *   then move on to 10/100.
 */
int genphy_read_status(struct phy_device *phydev)
{
	int adv;
	int err;
	int lpa;
	int lpagb = 0;

	/* Update the link, but return if there
	 * was an error */
	err = genphy_update_link(phydev);
	if (err)
		return err;

	if (AUTONEG_ENABLE == phydev->autoneg) {
		if (phydev->supported & (SUPPORTED_1000baseT_Half
					| SUPPORTED_1000baseT_Full)) {
			lpagb = phy_read(phydev, MII_STAT1000);

			if (lpagb < 0)
				return lpagb;

			adv = phy_read(phydev, MII_CTRL1000);

			if (adv < 0)
				return adv;

			lpagb &= adv << 2;
		}

		lpa = phy_read(phydev, MII_LPA);

		if (lpa < 0)
			return lpa;

		adv = phy_read(phydev, MII_ADVERTISE);

		if (adv < 0)
			return adv;

		lpa &= adv;

		phydev->speed = SPEED_10;
		phydev->duplex = DUPLEX_HALF;
		phydev->pause = phydev->asym_pause = 0;

		if (lpagb & (LPA_1000FULL | LPA_1000HALF)) {
			phydev->speed = SPEED_1000;

			if (lpagb & LPA_1000FULL)
				phydev->duplex = DUPLEX_FULL;
		} else if (lpa & (LPA_100FULL | LPA_100HALF)) {
			phydev->speed = SPEED_100;

			if (lpa & LPA_100FULL)
				phydev->duplex = DUPLEX_FULL;
		} else
			if (lpa & LPA_10FULL)
				phydev->duplex = DUPLEX_FULL;

		if (phydev->duplex == DUPLEX_FULL){
			phydev->pause = lpa & LPA_PAUSE_CAP ? 1 : 0;
			phydev->asym_pause = lpa & LPA_PAUSE_ASYM ? 1 : 0;
		}
	} else {
		int bmcr = phy_read(phydev, MII_BMCR);
		if (bmcr < 0)
			return bmcr;

		if (bmcr & BMCR_FULLDPLX)
			phydev->duplex = DUPLEX_FULL;
		else
			phydev->duplex = DUPLEX_HALF;

		if (bmcr & BMCR_SPEED1000)
			phydev->speed = SPEED_1000;
		else if (bmcr & BMCR_SPEED100)
			phydev->speed = SPEED_100;
		else
			phydev->speed = SPEED_10;

		phydev->pause = phydev->asym_pause = 0;
	}

	return 0;
}
EXPORT_SYMBOL(genphy_read_status);

static int genphy_config_init(struct phy_device *phydev)
{
	int val;
	u32 features;

	/* For now, I'll claim that the generic driver supports
	 * all possible port types */
	features = (SUPPORTED_TP | SUPPORTED_MII
			| SUPPORTED_AUI | SUPPORTED_FIBRE |
			SUPPORTED_BNC);

	/* Do we support autonegotiation? */
	val = phy_read(phydev, MII_BMSR);

	if (val < 0)
		return val;

	if (val & BMSR_ANEGCAPABLE)
		features |= SUPPORTED_Autoneg;

	if (val & BMSR_100FULL)
		features |= SUPPORTED_100baseT_Full;
	if (val & BMSR_100HALF)
		features |= SUPPORTED_100baseT_Half;
	if (val & BMSR_10FULL)
		features |= SUPPORTED_10baseT_Full;
	if (val & BMSR_10HALF)
		features |= SUPPORTED_10baseT_Half;

	if (val & BMSR_ESTATEN) {
		val = phy_read(phydev, MII_ESTATUS);

		if (val < 0)
			return val;

		if (val & ESTATUS_1000_TFULL)
			features |= SUPPORTED_1000baseT_Full;
		if (val & ESTATUS_1000_THALF)
			features |= SUPPORTED_1000baseT_Half;
	}

	phydev->supported = features;
	phydev->advertising = features;

	return 0;
}
int genphy_suspend(struct phy_device *phydev)
{
	int value;

	mutex_lock(&phydev->lock);

	value = phy_read(phydev, MII_BMCR);
	phy_write(phydev, MII_BMCR, (value | BMCR_PDOWN));

	mutex_unlock(&phydev->lock);

	return 0;
}
EXPORT_SYMBOL(genphy_suspend);

int genphy_resume(struct phy_device *phydev)
{
	int value;

	mutex_lock(&phydev->lock);

	value = phy_read(phydev, MII_BMCR);
	phy_write(phydev, MII_BMCR, (value & ~BMCR_PDOWN));

	mutex_unlock(&phydev->lock);

	return 0;
}
EXPORT_SYMBOL(genphy_resume);

/**
 * phy_probe - probe and init a PHY device
 * @dev: device to probe and init
 *
 * Description: Take care of setting up the phy_device structure,
 *   set the state to READY (the driver's init function should
 *   set it to STARTING if needed).
 */
static int phy_probe(struct device *dev)
{
	struct phy_device *phydev;
	struct phy_driver *phydrv;
	struct device_driver *drv;
	int err = 0;

	phydev = to_phy_device(dev);

	drv = phydev->dev.driver;
	phydrv = to_phy_driver(drv);
	phydev->drv = phydrv;

	/* Disable the interrupt if the PHY doesn't support it
	 * but the interrupt is still a valid one
	 */
	if (!(phydrv->flags & PHY_HAS_INTERRUPT) &&
			phy_interrupt_is_valid(phydev))
		phydev->irq = PHY_POLL;

	if (phydrv->flags & PHY_IS_INTERNAL)
		phydev->is_internal = true;

	mutex_lock(&phydev->lock);

	/* Start out supporting everything. Eventually,
	 * a controller will attach, and may modify one
	 * or both of these values */
	phydev->supported = phydrv->features;
	phydev->advertising = phydrv->features;

	/* Set the state to READY by default */
	phydev->state = PHY_READY;

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

	mutex_unlock(&phydev->lock);

	return err;

}

static int phy_remove(struct device *dev)
{
	struct phy_device *phydev;

	phydev = to_phy_device(dev);

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

	if (phydev->drv->remove)
		phydev->drv->remove(phydev);
	phydev->drv = NULL;

	return 0;
}

/**
 * phy_driver_register - register a phy_driver with the PHY layer
 * @new_driver: new phy_driver to register
 */
int phy_driver_register(struct phy_driver *new_driver)
{
	int retval;

	new_driver->driver.name = new_driver->name;
	new_driver->driver.bus = &mdio_bus_type;
	new_driver->driver.probe = phy_probe;
	new_driver->driver.remove = phy_remove;

	retval = driver_register(&new_driver->driver);

	if (retval) {
		pr_err("%s: Error %d in registering driver\n",
		       new_driver->name, retval);

		return retval;
	}

	pr_debug("%s: Registered new driver\n", new_driver->name);

	return 0;
}
EXPORT_SYMBOL(phy_driver_register);

int phy_drivers_register(struct phy_driver *new_driver, int n)
{
	int i, ret = 0;

	for (i = 0; i < n; i++) {
		ret = phy_driver_register(new_driver + i);
		if (ret) {
			while (i-- > 0)
				phy_driver_unregister(new_driver + i);
			break;
		}
	}
	return ret;
}
EXPORT_SYMBOL(phy_drivers_register);

void phy_driver_unregister(struct phy_driver *drv)
{
	driver_unregister(&drv->driver);
}
EXPORT_SYMBOL(phy_driver_unregister);

void phy_drivers_unregister(struct phy_driver *drv, int n)
{
	int i;
	for (i = 0; i < n; i++) {
		phy_driver_unregister(drv + i);
	}
}
EXPORT_SYMBOL(phy_drivers_unregister);

static struct phy_driver genphy_driver = {
	.phy_id		= 0xffffffff,
	.phy_id_mask	= 0xffffffff,
	.name		= "Generic PHY",
	.config_init	= genphy_config_init,
	.features	= 0,
	.config_aneg	= genphy_config_aneg,
	.read_status	= genphy_read_status,
	.suspend	= genphy_suspend,
	.resume		= genphy_resume,
	.driver		= {.owner= THIS_MODULE, },
};

static int __init phy_init(void)
{
	int rc;

	rc = mdio_bus_init();
	if (rc)
		return rc;

	rc = phy_driver_register(&genphy_driver);
	if (rc)
		mdio_bus_exit();

	return rc;
}

static void __exit phy_exit(void)
{
	phy_driver_unregister(&genphy_driver);
	mdio_bus_exit();
}

subsys_initcall(phy_init);
module_exit(phy_exit);