/*

   * drivers/base/dd.c - The core device/driver interactions.

   *

   * This file contains the (sometimes tricky) code that controls the
   * interactions between devices and drivers, which primarily includes
   * driver binding and unbinding.

   *

   * All of this code used to exist in drivers/base/bus.c, but was
   * relocated to here in the name of compartmentalization (since it wasn't
   * strictly code just for the 'struct bus_type'.

   *

   * Copyright (c) 2002-5 Patrick Mochel
   * Copyright (c) 2002-3 Open Source Development Labs

   * Copyright (c) 2007-2009 Greg Kroah-Hartman <gregkh@suse.de>
   * Copyright (c) 2007-2009 Novell Inc.

   *

   * This file is released under the GPLv2

   */
  
  #include <linux/device.h>

  #include <linux/delay.h>

  #include <linux/module.h>

  #include <linux/kthread.h>

  #include <linux/wait.h>

  #include <linux/async.h>

  #include <linux/pm_runtime.h>

  
  #include "base.h"
  #include "power/power.h"

  static void driver_bound(struct device *dev)

  {

  	if (klist_node_attached(&dev->p->knode_driver)) {

  		printk(KERN_WARNING "%s: device %s already bound
  ",

  			__func__, kobject_name(&dev->kobj));

  		return;

  	}

  	pr_debug("driver: '%s': %s: bound to device '%s'
  ", dev_name(dev),

  		 __func__, dev->driver->name);

  	klist_add_tail(&dev->p->knode_driver, &dev->driver->p->klist_devices);

  	if (dev->bus)

  		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,

  					     BUS_NOTIFY_BOUND_DRIVER, dev);

  }
  
  static int driver_sysfs_add(struct device *dev)
  {
  	int ret;

  	if (dev->bus)
  		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
  					     BUS_NOTIFY_BIND_DRIVER, dev);

  	ret = sysfs_create_link(&dev->driver->p->kobj, &dev->kobj,

  			  kobject_name(&dev->kobj));

  	if (ret == 0) {

  		ret = sysfs_create_link(&dev->kobj, &dev->driver->p->kobj,

  					"driver");
  		if (ret)

  			sysfs_remove_link(&dev->driver->p->kobj,

  					kobject_name(&dev->kobj));
  	}
  	return ret;

  }

  static void driver_sysfs_remove(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  
  	if (drv) {

  		sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));

  		sysfs_remove_link(&dev->kobj, "driver");
  	}
  }
  
  /**

   * device_bind_driver - bind a driver to one device.
   * @dev: device.

   *

   * Allow manual attachment of a driver to a device.
   * Caller must have already set @dev->driver.

   *

   * Note that this does not modify the bus reference count
   * nor take the bus's rwsem. Please verify those are accounted
   * for before calling this. (It is ok to call with no other effort
   * from a driver's probe() method.)

   *

   * This function must be called with the device lock held.

   */
  int device_bind_driver(struct device *dev)
  {

  	int ret;
  
  	ret = driver_sysfs_add(dev);
  	if (!ret)
  		driver_bound(dev);
  	return ret;

  }

  EXPORT_SYMBOL_GPL(device_bind_driver);

  static atomic_t probe_count = ATOMIC_INIT(0);

  static DECLARE_WAIT_QUEUE_HEAD(probe_waitqueue);

  static int really_probe(struct device *dev, struct device_driver *drv)

  {

  	int ret = 0;

  	atomic_inc(&probe_count);

  	pr_debug("bus: '%s': %s: probing driver %s with device %s
  ",

  		 drv->bus->name, __func__, drv->name, dev_name(dev));

  	WARN_ON(!list_empty(&dev->devres_head));

  	dev->driver = drv;

  	if (driver_sysfs_add(dev)) {
  		printk(KERN_ERR "%s: driver_sysfs_add(%s) failed
  ",

  			__func__, dev_name(dev));

  		goto probe_failed;
  	}

  	if (dev->bus->probe) {
  		ret = dev->bus->probe(dev);

  		if (ret)

  			goto probe_failed;

  	} else if (drv->probe) {

  		ret = drv->probe(dev);

  		if (ret)

  			goto probe_failed;

  	}

  
  	driver_bound(dev);

  	ret = 1;

  	pr_debug("bus: '%s': %s: bound device %s to driver %s
  ",

  		 drv->bus->name, __func__, dev_name(dev), drv->name);

  	goto done;

  probe_failed:

  	devres_release_all(dev);

  	driver_sysfs_remove(dev);
  	dev->driver = NULL;

  	if (ret != -ENODEV && ret != -ENXIO) {

  		/* driver matched but the probe failed */
  		printk(KERN_WARNING
  		       "%s: probe of %s failed with error %d
  ",

  		       drv->name, dev_name(dev), ret);

  	} else {
  		pr_debug("%s: probe of %s rejects match %d
  ",
  		       drv->name, dev_name(dev), ret);

  	}

  	/*
  	 * Ignore errors returned by ->probe so that the next driver can try
  	 * its luck.
  	 */
  	ret = 0;

  done:

  	atomic_dec(&probe_count);

  	wake_up(&probe_waitqueue);

  	return ret;
  }
  
  /**
   * driver_probe_done
   * Determine if the probe sequence is finished or not.
   *
   * Should somehow figure out how to use a semaphore, not an atomic variable...
   */
  int driver_probe_done(void)
  {

  	pr_debug("%s: probe_count = %d
  ", __func__,

  		 atomic_read(&probe_count));
  	if (atomic_read(&probe_count))
  		return -EBUSY;
  	return 0;
  }
  
  /**

   * wait_for_device_probe
   * Wait for device probing to be completed.

   */

  void wait_for_device_probe(void)

  {
  	/* wait for the known devices to complete their probing */

  	wait_event(probe_waitqueue, atomic_read(&probe_count) == 0);

  	async_synchronize_full();

  }

  EXPORT_SYMBOL_GPL(wait_for_device_probe);

  
  /**

   * driver_probe_device - attempt to bind device & driver together
   * @drv: driver to bind a device to
   * @dev: device to try to bind to the driver
   *

   * This function returns -ENODEV if the device is not registered,

   * 1 if the device is bound successfully and 0 otherwise.

   *

   * This function must be called with @dev lock held.  When called for a
   * USB interface, @dev->parent lock must be held as well.

   */

  int driver_probe_device(struct device_driver *drv, struct device *dev)

  {

  	int ret = 0;

  	if (!device_is_registered(dev))
  		return -ENODEV;

  	pr_debug("bus: '%s': %s: matched device %s with driver %s
  ",

  		 drv->bus->name, __func__, dev_name(dev), drv->name);

  	pm_runtime_get_noresume(dev);
  	pm_runtime_barrier(dev);

  	ret = really_probe(dev, drv);

  	pm_runtime_put_sync(dev);

  	return ret;

  }

  static int __device_attach(struct device_driver *drv, void *data)

  {

  	struct device *dev = data;

  
  	if (!driver_match_device(drv, dev))
  		return 0;

  	return driver_probe_device(drv, dev);

  }

  /**

   * device_attach - try to attach device to a driver.
   * @dev: device.

   *

   * Walk the list of drivers that the bus has and call
   * driver_probe_device() for each pair. If a compatible
   * pair is found, break out and return.

   *

   * Returns 1 if the device was bound to a driver;

   * 0 if no matching driver was found;

   * -ENODEV if the device is not registered.

   *

   * When called for a USB interface, @dev->parent lock must be held.

   */

  int device_attach(struct device *dev)

  {

  	int ret = 0;

  	device_lock(dev);

  	if (dev->driver) {

  		if (klist_node_attached(&dev->p->knode_driver)) {
  			ret = 1;
  			goto out_unlock;
  		}

  		ret = device_bind_driver(dev);
  		if (ret == 0)
  			ret = 1;

  		else {
  			dev->driver = NULL;
  			ret = 0;
  		}

  	} else {

  		pm_runtime_get_noresume(dev);

  		ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);

  		pm_runtime_put_sync(dev);

  	}

  out_unlock:

  	device_unlock(dev);

  	return ret;

  }

  EXPORT_SYMBOL_GPL(device_attach);

  static int __driver_attach(struct device *dev, void *data)

  {

  	struct device_driver *drv = data;

  
  	/*
  	 * Lock device and try to bind to it. We drop the error
  	 * here and always return 0, because we need to keep trying
  	 * to bind to devices and some drivers will return an error
  	 * simply if it didn't support the device.
  	 *
  	 * driver_probe_device() will spit a warning if there
  	 * is an error.
  	 */

  	if (!driver_match_device(drv, dev))

  		return 0;

  	if (dev->parent)	/* Needed for USB */

  		device_lock(dev->parent);
  	device_lock(dev);

  	if (!dev->driver)
  		driver_probe_device(drv, dev);

  	device_unlock(dev);

  	if (dev->parent)

  		device_unlock(dev->parent);

  	return 0;
  }
  
  /**

   * driver_attach - try to bind driver to devices.
   * @drv: driver.

   *

   * Walk the list of devices that the bus has on it and try to
   * match the driver with each one.  If driver_probe_device()
   * returns 0 and the @dev->driver is set, we've found a
   * compatible pair.

   */

  int driver_attach(struct device_driver *drv)

  {

  	return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);

  }

  EXPORT_SYMBOL_GPL(driver_attach);

  /*

   * __device_release_driver() must be called with @dev lock held.
   * When called for a USB interface, @dev->parent lock must be held as well.

   */

  static void __device_release_driver(struct device *dev)

  {

  	struct device_driver *drv;

  	drv = dev->driver;

  	if (drv) {

  		pm_runtime_get_sync(dev);

  		driver_sysfs_remove(dev);

  		if (dev->bus)

  			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,

  						     BUS_NOTIFY_UNBIND_DRIVER,
  						     dev);

  		pm_runtime_put_sync(dev);

  		if (dev->bus && dev->bus->remove)

  			dev->bus->remove(dev);
  		else if (drv->remove)

  			drv->remove(dev);

  		devres_release_all(dev);

  		dev->driver = NULL;

  		klist_remove(&dev->p->knode_driver);

  		if (dev->bus)
  			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
  						     BUS_NOTIFY_UNBOUND_DRIVER,
  						     dev);

  	}

  }

  /**

   * device_release_driver - manually detach device from driver.
   * @dev: device.

   *

   * Manually detach device from driver.

   * When called for a USB interface, @dev->parent lock must be held.

   */

  void device_release_driver(struct device *dev)

  {

  	/*
  	 * If anyone calls device_release_driver() recursively from
  	 * within their ->remove callback for the same device, they
  	 * will deadlock right here.
  	 */

  	device_lock(dev);

  	__device_release_driver(dev);

  	device_unlock(dev);

  }

  EXPORT_SYMBOL_GPL(device_release_driver);

  /**
   * driver_detach - detach driver from all devices it controls.
   * @drv: driver.
   */

  void driver_detach(struct device_driver *drv)

  {

  	struct device_private *dev_prv;

  	struct device *dev;

  
  	for (;;) {

  		spin_lock(&drv->p->klist_devices.k_lock);
  		if (list_empty(&drv->p->klist_devices.k_list)) {
  			spin_unlock(&drv->p->klist_devices.k_lock);

  			break;
  		}

  		dev_prv = list_entry(drv->p->klist_devices.k_list.prev,
  				     struct device_private,
  				     knode_driver.n_node);
  		dev = dev_prv->device;

  		get_device(dev);

  		spin_unlock(&drv->p->klist_devices.k_lock);

  		if (dev->parent)	/* Needed for USB */

  			device_lock(dev->parent);
  		device_lock(dev);

  		if (dev->driver == drv)
  			__device_release_driver(dev);

  		device_unlock(dev);

  		if (dev->parent)

  			device_unlock(dev->parent);

  		put_device(dev);
  	}

  }

  
  /*
   * These exports can't be _GPL due to .h files using this within them, and it
   * might break something that was previously working...
   */
  void *dev_get_drvdata(const struct device *dev)
  {
  	if (dev && dev->p)
  		return dev->p->driver_data;
  	return NULL;
  }
  EXPORT_SYMBOL(dev_get_drvdata);

  int dev_set_drvdata(struct device *dev, void *data)

  {
  	int error;

  	if (!dev->p) {
  		error = device_private_init(dev);
  		if (error)

  			return error;

  	}
  	dev->p->driver_data = data;

  	return 0;

  }
  EXPORT_SYMBOL(dev_set_drvdata);