/* 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.
   *
   */

  
  #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/device.h>

  #include <linux/of_device.h>

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

  #include <asm/irq.h>

  int mdiobus_register_device(struct mdio_device *mdiodev)
  {
  	if (mdiodev->bus->mdio_map[mdiodev->addr])
  		return -EBUSY;
  
  	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
  
  	return 0;
  }
  EXPORT_SYMBOL(mdiobus_register_device);
  
  int mdiobus_unregister_device(struct mdio_device *mdiodev)
  {
  	if (mdiodev->bus->mdio_map[mdiodev->addr] != mdiodev)
  		return -EINVAL;
  
  	mdiodev->bus->mdio_map[mdiodev->addr] = NULL;
  
  	return 0;
  }
  EXPORT_SYMBOL(mdiobus_unregister_device);
  
  struct phy_device *mdiobus_get_phy(struct mii_bus *bus, int addr)
  {
  	struct mdio_device *mdiodev = bus->mdio_map[addr];
  
  	if (!mdiodev)
  		return NULL;
  
  	if (!(mdiodev->flags & MDIO_DEVICE_FLAG_PHY))
  		return NULL;
  
  	return container_of(mdiodev, struct phy_device, mdio);
  }
  EXPORT_SYMBOL(mdiobus_get_phy);
  
  bool mdiobus_is_registered_device(struct mii_bus *bus, int addr)
  {
  	return bus->mdio_map[addr];
  }
  EXPORT_SYMBOL(mdiobus_is_registered_device);

  /**

   * mdiobus_alloc_size - allocate a mii_bus structure

   * @size: extra amount of memory to allocate for private storage.
   * If non-zero, then bus->priv is points to that memory.

   *
   * Description: called by a bus driver to allocate an mii_bus
   * structure to fill in.
   */

  struct mii_bus *mdiobus_alloc_size(size_t size)

  {

  	struct mii_bus *bus;

  	size_t aligned_size = ALIGN(sizeof(*bus), NETDEV_ALIGN);
  	size_t alloc_size;

  	int i;

  
  	/* If we alloc extra space, it should be aligned */
  	if (size)
  		alloc_size = aligned_size + size;
  	else
  		alloc_size = sizeof(*bus);

  	bus = kzalloc(alloc_size, GFP_KERNEL);

  	if (!bus)
  		return NULL;
  
  	bus->state = MDIOBUS_ALLOCATED;
  	if (size)
  		bus->priv = (void *)bus + aligned_size;

  	/* Initialise the interrupts to polling */
  	for (i = 0; i < PHY_MAX_ADDR; i++)
  		bus->irq[i] = PHY_POLL;

  	return bus;

  }

  EXPORT_SYMBOL(mdiobus_alloc_size);

  static void _devm_mdiobus_free(struct device *dev, void *res)
  {
  	mdiobus_free(*(struct mii_bus **)res);
  }
  
  static int devm_mdiobus_match(struct device *dev, void *res, void *data)
  {
  	struct mii_bus **r = res;
  
  	if (WARN_ON(!r || !*r))
  		return 0;
  
  	return *r == data;
  }
  
  /**
   * devm_mdiobus_alloc_size - Resource-managed mdiobus_alloc_size()
   * @dev:		Device to allocate mii_bus for
   * @sizeof_priv:	Space to allocate for private structure.
   *
   * Managed mdiobus_alloc_size. mii_bus allocated with this function is
   * automatically freed on driver detach.
   *
   * If an mii_bus allocated with this function needs to be freed separately,
   * devm_mdiobus_free() must be used.
   *
   * RETURNS:
   * Pointer to allocated mii_bus on success, NULL on failure.
   */
  struct mii_bus *devm_mdiobus_alloc_size(struct device *dev, int sizeof_priv)
  {
  	struct mii_bus **ptr, *bus;
  
  	ptr = devres_alloc(_devm_mdiobus_free, sizeof(*ptr), GFP_KERNEL);
  	if (!ptr)
  		return NULL;
  
  	/* use raw alloc_dr for kmalloc caller tracing */
  	bus = mdiobus_alloc_size(sizeof_priv);
  	if (bus) {
  		*ptr = bus;
  		devres_add(dev, ptr);
  	} else {
  		devres_free(ptr);
  	}
  
  	return bus;
  }

  EXPORT_SYMBOL_GPL(devm_mdiobus_alloc_size);

  
  /**
   * devm_mdiobus_free - Resource-managed mdiobus_free()
   * @dev:		Device this mii_bus belongs to
   * @bus:		the mii_bus associated with the device
   *
   * Free mii_bus allocated with devm_mdiobus_alloc_size().
   */
  void devm_mdiobus_free(struct device *dev, struct mii_bus *bus)
  {
  	int rc;
  
  	rc = devres_release(dev, _devm_mdiobus_free,
  			    devm_mdiobus_match, bus);
  	WARN_ON(rc);
  }
  EXPORT_SYMBOL_GPL(devm_mdiobus_free);

  /**

   * 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,
  };

  #if IS_ENABLED(CONFIG_OF_MDIO)

  /* Helper function for of_mdio_find_bus */

  static int of_mdio_bus_match(struct device *dev, const void *mdio_bus_np)

  {
  	return dev->of_node == mdio_bus_np;
  }
  /**
   * of_mdio_find_bus - Given an mii_bus node, find the mii_bus.

   * @mdio_bus_np: Pointer to the mii_bus.

   *

   * Returns a reference to the mii_bus, or NULL if none found.  The
   * embedded struct device will have its reference count incremented,
   * and this must be put once the bus is finished with.

   *
   * Because the association of a device_node and mii_bus is made via
   * of_mdiobus_register(), the mii_bus cannot be found before it is
   * registered with of_mdiobus_register().
   *
   */
  struct mii_bus *of_mdio_find_bus(struct device_node *mdio_bus_np)
  {
  	struct device *d;
  
  	if (!mdio_bus_np)
  		return NULL;
  
  	d = class_find_device(&mdio_bus_class, NULL,  mdio_bus_np,
  			      of_mdio_bus_match);
  
  	return d ? to_mii_bus(d) : NULL;
  }
  EXPORT_SYMBOL(of_mdio_find_bus);

  /* Walk the list of subnodes of a mdio bus and look for a node that
   * matches the mdio device's address with its 'reg' property. If
   * found, set the of_node pointer for the mdio device. This allows
   * auto-probed phy devices to be supplied with information passed in
   * via DT.

   */

  static void of_mdiobus_link_mdiodev(struct mii_bus *bus,
  				    struct mdio_device *mdiodev)

  {

  	struct device *dev = &mdiodev->dev;

  	struct device_node *child;

  	if (dev->of_node || !bus->dev.of_node)

  		return;

  	for_each_available_child_of_node(bus->dev.of_node, child) {

  		int addr;
  		int ret;
  
  		ret = of_property_read_u32(child, "reg", &addr);
  		if (ret < 0) {

  			dev_err(dev, "%s has invalid MDIO address
  ",

  				child->full_name);
  			continue;
  		}

  		/* A MDIO device must have a reg property in the range [0-31] */

  		if (addr >= PHY_MAX_ADDR) {

  			dev_err(dev, "%s MDIO address %i is too large
  ",

  				child->full_name, addr);
  			continue;
  		}

  		if (addr == mdiodev->addr) {

  			dev->of_node = child;
  			return;
  		}
  	}
  }
  #else /* !IS_ENABLED(CONFIG_OF_MDIO) */

  static inline void of_mdiobus_link_mdiodev(struct mii_bus *mdio,
  					   struct mdio_device *mdiodev)

  {
  }

  #endif

  /**

   * __mdiobus_register - bring up all the PHYs on a given bus and attach them to bus

   * @bus: target mii_bus

   * @owner: module containing bus accessor functions

   *

   * Description: Called by a bus driver to bring up all the PHYs

   *   on a given bus, and attach them to the bus. Drivers should use
   *   mdiobus_register() rather than __mdiobus_register() unless they

   *   need to pass a specific owner module. MDIO devices which are not
   *   PHYs will not be brought up by this function. They are expected to
   *   to be explicitly listed in DT and instantiated by of_mdiobus_register().

   *
   * Returns 0 on success or < 0 on error.

   */

  int __mdiobus_register(struct mii_bus *bus, struct module *owner)

  {

  	struct mdio_device *mdiodev;

  	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->owner = owner;

  	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) {

  		pr_err("mii_bus %s failed to register
  ", bus->id);

  		put_device(&bus->dev);

  		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) && (PTR_ERR(phydev) != -ENODEV)) {

  				err = PTR_ERR(phydev);

  				goto error;
  			}

  		}

  	}

  	bus->state = MDIOBUS_REGISTERED;

  	pr_info("%s: probed
  ", bus->name);

  	return 0;

  error:
  	while (--i >= 0) {

  		mdiodev = bus->mdio_map[i];
  		if (!mdiodev)
  			continue;
  
  		mdiodev->device_remove(mdiodev);
  		mdiodev->device_free(mdiodev);

  	}
  	device_del(&bus->dev);

  	return err;
  }

  EXPORT_SYMBOL(__mdiobus_register);

  
  void mdiobus_unregister(struct mii_bus *bus)
  {

  	struct mdio_device *mdiodev;

  	int i;

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

  	for (i = 0; i < PHY_MAX_ADDR; i++) {

  		mdiodev = bus->mdio_map[i];
  		if (!mdiodev)
  			continue;

  		mdiodev->device_remove(mdiodev);
  		mdiodev->device_free(mdiodev);

  	}

  	device_del(&bus->dev);

  }
  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);

  /**
   * mdiobus_scan - scan a bus for MDIO devices.
   * @bus: mii_bus to scan
   * @addr: address on bus to scan
   *
   * This function scans the MDIO bus, looking for devices which can be
   * identified using a vendor/product ID in registers 2 and 3. Not all
   * MDIO devices have such registers, but PHY devices typically
   * do. Hence this function assumes anything found is a PHY, or can be
   * treated as a PHY. Other MDIO devices, such as switches, will
   * probably not be found during the scan.
   */

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

  	phydev = get_phy_device(bus, addr, false);

  	if (IS_ERR(phydev))

  		return phydev;

  	/*
  	 * For DT, see if the auto-probed phy has a correspoding child
  	 * in the bus node, and set the of_node pointer in this case.
  	 */

  	of_mdiobus_link_mdiodev(bus, &phydev->mdio);

  	err = phy_device_register(phydev);

  	if (err) {

  		phy_device_free(phydev);

  		return ERR_PTR(-ENODEV);

  	}

  	return phydev;
  }
  EXPORT_SYMBOL(mdiobus_scan);

  /**

   * mdiobus_read_nested - Nested version of the mdiobus_read function
   * @bus: the mii_bus struct
   * @addr: the phy address
   * @regnum: register number to read
   *
   * In case of nested MDIO bus access avoid lockdep false positives by
   * using mutex_lock_nested().
   *
   * 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_nested(struct mii_bus *bus, int addr, u32 regnum)
  {
  	int retval;
  
  	BUG_ON(in_interrupt());

  	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);

  	retval = bus->read(bus, addr, regnum);
  	mutex_unlock(&bus->mdio_lock);
  
  	return retval;
  }
  EXPORT_SYMBOL(mdiobus_read_nested);
  
  /**

   * 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_nested - Nested version of the mdiobus_write function
   * @bus: the mii_bus struct
   * @addr: the phy address
   * @regnum: register number to write
   * @val: value to write to @regnum
   *
   * In case of nested MDIO bus access avoid lockdep false positives by
   * using mutex_lock_nested().
   *
   * 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_nested(struct mii_bus *bus, int addr, u32 regnum, u16 val)
  {
  	int err;
  
  	BUG_ON(in_interrupt());

  	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);

  	err = bus->write(bus, addr, regnum, val);
  	mutex_unlock(&bus->mdio_lock);
  
  	return err;
  }
  EXPORT_SYMBOL(mdiobus_write_nested);
  
  /**

   * 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 MDIO driver supports the given
   *		    MDIO device
   * @dev: target MDIO device
   * @drv: given MDIO driver

   *

   * Description: Given a MDIO device, and a MDIO driver, return 1 if
   *   the driver supports the device.  Otherwise, return 0. This may
   *   require calling the devices own match function, since different classes
   *   of MDIO devices have different match criteria.

   */
  static int mdio_bus_match(struct device *dev, struct device_driver *drv)
  {

  	struct mdio_device *mdio = to_mdio_device(dev);

  	if (of_driver_match_device(dev, drv))
  		return 1;

  	if (mdio->bus_match)
  		return mdio->bus_match(dev, drv);

  	return 0;

  }

  #ifdef CONFIG_PM

  static int mdio_bus_suspend(struct device *dev)

  {

  	struct mdio_device *mdio = to_mdio_device(dev);

  	if (mdio->pm_ops && mdio->pm_ops->suspend)
  		return mdio->pm_ops->suspend(dev);

  	return 0;

  }

  static int mdio_bus_resume(struct device *dev)

  {

  	struct mdio_device *mdio = to_mdio_device(dev);

  	if (mdio->pm_ops && mdio->pm_ops->resume)
  		return mdio->pm_ops->resume(dev);

  
  	return 0;

  }

  static int mdio_bus_restore(struct device *dev)
  {

  	struct mdio_device *mdio = to_mdio_device(dev);

  	if (mdio->pm_ops && mdio->pm_ops->restore)
  		return mdio->pm_ops->restore(dev);

  
  	return 0;
  }

  static const 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);
  }