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 <linux/mdio.h>
#include <linux/io.h>
#include <linux/uaccess.h>

#include <asm/irq.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));
}

enum genphy_driver {
	GENPHY_DRV_1G,
	GENPHY_DRV_10G,
	GENPHY_DRV_MAX
};

static struct phy_driver genphy_driver[GENPHY_DRV_MAX];

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

/**
 * phy_register_fixup - 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 = kzalloc(sizeof(*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 */
static 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 = fixup->run(phydev);

			if (err < 0) {
				mutex_unlock(&phy_fixup_lock);
				return err;
			}
			phydev->has_fixups = true;
		}
	}
	mutex_unlock(&phy_fixup_lock);

	return 0;
}

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 = 0;
	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};
	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;

	return phy_device_create(bus, addr, phy_id, is_c45, &c45_ids);
}
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 */
	err = phy_init_hw(phydev);
	if (err) {
		pr_err("PHY %d failed to initialize\n", phydev->addr);
		goto out;
	}

	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);
	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);

/**
 * phy_poll_reset - Safely wait until a PHY reset has properly completed
 * @phydev: The PHY device to poll
 *
 * Description: According to IEEE 802.3, Section 2, Subsection 22.2.4.1.1, as
 *   published in 2008, a PHY reset may take up to 0.5 seconds.  The MII BMCR
 *   register must be polled until the BMCR_RESET bit clears.
 *
 *   Furthermore, any attempts to write to PHY registers may have no effect
 *   or even generate MDIO bus errors until this is complete.
 *
 *   Some PHYs (such as the Marvell 88E1111) don't entirely conform to the
 *   standard and do not fully reset after the BMCR_RESET bit is set, and may
 *   even *REQUIRE* a soft-reset to properly restart autonegotiation.  In an
 *   effort to support such broken PHYs, this function is separate from the
 *   standard phy_init_hw() which will zero all the other bits in the BMCR
 *   and reapply all driver-specific and board-specific fixups.
 */
static int phy_poll_reset(struct phy_device *phydev)
{
	/* Poll until the reset bit clears (50ms per retry == 0.6 sec) */
	unsigned int retries = 12;
	int ret;

	do {
		msleep(50);
		ret = phy_read(phydev, MII_BMCR);
		if (ret < 0)
			return ret;
	} while (ret & BMCR_RESET && --retries);
	if (ret & BMCR_RESET)
		return -ETIMEDOUT;

	/* Some chips (smsc911x) may still need up to another 1ms after the
	 * BMCR_RESET bit is cleared before they are usable.
	 */
	msleep(1);
	return 0;
}

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

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

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

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

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

/**
 * 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 a
 *     generic 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.
 */
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)
			d->driver = &genphy_driver[GENPHY_DRV_10G].driver;
		else
			d->driver = &genphy_driver[GENPHY_DRV_1G].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);

	phy_resume(phydev);

	return err;
}
EXPORT_SYMBOL(phy_attach_direct);

/**
 * 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)
{
	int i;
	phydev->attached_dev->phydev = NULL;
	phydev->attached_dev = NULL;
	phy_suspend(phydev);

	/* 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
	 */
	for (i = 0; i < ARRAY_SIZE(genphy_driver); i++) {
		if (phydev->dev.driver == &genphy_driver[i].driver) {
			device_release_driver(&phydev->dev);
			break;
		}
	}
}
EXPORT_SYMBOL(phy_detach);

int phy_suspend(struct phy_device *phydev)
{
	struct phy_driver *phydrv = to_phy_driver(phydev->dev.driver);
	struct ethtool_wolinfo wol;

	/* If the device has WOL enabled, we cannot suspend the PHY */
	wol.cmd = ETHTOOL_GWOL;
	phy_ethtool_get_wol(phydev, &wol);
	if (wol.wolopts)
		return -EBUSY;

	if (phydrv->suspend)
		return phydrv->suspend(phydev);
	return 0;
}

int phy_resume(struct phy_device *phydev)
{
	struct phy_driver *phydrv = to_phy_driver(phydev->dev.driver);

	if (phydrv->resume)
		return phydrv->resume(phydev);
	return 0;
}

/* 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, bmsr;
	int err, changed = 0;

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

	/* Setup standard advertisement */
	adv = phy_read(phydev, MII_ADVERTISE);
	if (adv < 0)
		return adv;

	oldadv = 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;
	}

	bmsr = phy_read(phydev, MII_BMSR);
	if (bmsr < 0)
		return bmsr;

	/* Per 802.3-2008, Section 22.2.4.2.16 Extended status all
	 * 1000Mbits/sec capable PHYs shall have the BMSR_ESTATEN bit set to a
	 * logical 1.
	 */
	if (!(bmsr & BMSR_ESTATEN))
		return changed;

	/* Configure gigabit if it's supported */
	adv = phy_read(phydev, MII_CTRL1000);
	if (adv < 0)
		return adv;

	oldadv = adv;
	adv &= ~(ADVERTISE_1000FULL | ADVERTISE_1000HALF);

	if (phydev->supported & (SUPPORTED_1000baseT_Half |
				 SUPPORTED_1000baseT_Full)) {
		adv |= ethtool_adv_to_mii_ctrl1000_t(advertise);
		if (adv != oldadv)
			changed = 1;
	}

	err = phy_write(phydev, MII_CTRL1000, adv);
	if (err < 0)
		return err;

	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 ctl = 0;

	phydev->pause = 0;
	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;

	return phy_write(phydev, MII_BMCR, ctl);
}
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 = 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;

	return phy_write(phydev, MII_BMCR, 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_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.
 */
int genphy_aneg_done(struct phy_device *phydev)
{
	int retval = phy_read(phydev, MII_BMSR);

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

static int gen10g_config_aneg(struct phy_device *phydev)
{
	return 0;
}

/**
 * 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;

	phydev->lp_advertising = 0;

	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;

			phydev->lp_advertising =
				mii_stat1000_to_ethtool_lpa_t(lpagb);
			lpagb &= adv << 2;
		}

		lpa = phy_read(phydev, MII_LPA);
		if (lpa < 0)
			return lpa;

		phydev->lp_advertising |= mii_lpa_to_ethtool_lpa_t(lpa);

		adv = phy_read(phydev, MII_ADVERTISE);
		if (adv < 0)
			return adv;

		lpa &= adv;

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

	return 0;
}
EXPORT_SYMBOL(genphy_read_status);

static int gen10g_read_status(struct phy_device *phydev)
{
	int devad, reg;
	u32 mmd_mask = phydev->c45_ids.devices_in_package;

	phydev->link = 1;

	/* For now just lie and say it's 10G all the time */
	phydev->speed = SPEED_10000;
	phydev->duplex = DUPLEX_FULL;

	for (devad = 0; mmd_mask; devad++, mmd_mask = mmd_mask >> 1) {
		if (!(mmd_mask & 1))
			continue;

		/* Read twice because link state is latched and a
		 * read moves the current state into the register
		 */
		phy_read_mmd(phydev, devad, MDIO_STAT1);
		reg = phy_read_mmd(phydev, devad, MDIO_STAT1);
		if (reg < 0 || !(reg & MDIO_STAT1_LSTATUS))
			phydev->link = 0;
	}

	return 0;
}

/**
 * genphy_soft_reset - software reset the PHY via BMCR_RESET bit
 * @phydev: target phy_device struct
 *
 * Description: Perform a software PHY reset using the standard
 * BMCR_RESET bit and poll for the reset bit to be cleared.
 *
 * Returns: 0 on success, < 0 on failure
 */
int genphy_soft_reset(struct phy_device *phydev)
{
	int ret;

	ret = phy_write(phydev, MII_BMCR, BMCR_RESET);
	if (ret < 0)
		return ret;

	return phy_poll_reset(phydev);
}
EXPORT_SYMBOL(genphy_soft_reset);

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;
}

static int gen10g_config_init(struct phy_device *phydev)
{
	/* Temporarily just say we support everything */
	phydev->supported = SUPPORTED_10000baseT_Full;
	phydev->advertising = SUPPORTED_10000baseT_Full;

	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);

static int gen10g_suspend(struct phy_device *phydev)
{
	return 0;
}

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);

static int gen10g_resume(struct phy_device *phydev)
{
	return 0;
}

/**
 * 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 = to_phy_device(dev);
	struct device_driver *drv = phydev->dev.driver;
	struct phy_driver *phydrv = to_phy_driver(drv);
	int err = 0;

	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 = 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,
	.aneg_done	= genphy_aneg_done,
	.read_status	= genphy_read_status,
	.suspend	= genphy_suspend,
	.resume		= genphy_resume,
	.driver		= { .owner = THIS_MODULE, },
}, {
	.phy_id         = 0xffffffff,
	.phy_id_mask    = 0xffffffff,
	.name           = "Generic 10G PHY",
	.config_init    = gen10g_config_init,
	.features       = 0,
	.config_aneg    = gen10g_config_aneg,
	.read_status    = gen10g_read_status,
	.suspend        = gen10g_suspend,
	.resume         = gen10g_resume,
	.driver         = {.owner = THIS_MODULE, },
} };

static int __init phy_init(void)
{
	int rc;

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

	rc = phy_drivers_register(genphy_driver,
				  ARRAY_SIZE(genphy_driver));
	if (rc)
		mdio_bus_exit();

	return rc;
}

static void __exit phy_exit(void)
{
	phy_drivers_unregister(genphy_driver,
			       ARRAY_SIZE(genphy_driver));
	mdio_bus_exit();
}

subsys_initcall(phy_init);
module_exit(phy_exit);