/*
   * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
   *
   * Copyright (c) 2002-3 Patrick Mochel
   *               2002-3 Open Source Development Lab
   *
   * This file is released under the GPLv2
   *
   * This exports a 'system' bus type.
   * By default, a 'sys' bus gets added to the root of the system. There will
   * always be core system devices. Devices can use sysdev_register() to
   * add themselves as children of the system bus.
   */

  #include <linux/sysdev.h>
  #include <linux/err.h>
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/init.h>

  #include <linux/string.h>

  #include <linux/pm.h>

  #include <linux/device.h>

  #include <linux/mutex.h>

  #include <linux/interrupt.h>

  #include "base.h"

  #define to_sysdev(k) container_of(k, struct sys_device, kobj)
  #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)
  
  
  static ssize_t

  sysdev_show(struct kobject *kobj, struct attribute *attr, char *buffer)

  {

  	struct sys_device *sysdev = to_sysdev(kobj);
  	struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);

  
  	if (sysdev_attr->show)

  		return sysdev_attr->show(sysdev, sysdev_attr, buffer);

  	return -EIO;

  }
  
  
  static ssize_t

  sysdev_store(struct kobject *kobj, struct attribute *attr,
  	     const char *buffer, size_t count)

  {

  	struct sys_device *sysdev = to_sysdev(kobj);
  	struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);

  
  	if (sysdev_attr->store)

  		return sysdev_attr->store(sysdev, sysdev_attr, buffer, count);

  	return -EIO;

  }

  static const struct sysfs_ops sysfs_ops = {

  	.show	= sysdev_show,
  	.store	= sysdev_store,
  };
  
  static struct kobj_type ktype_sysdev = {
  	.sysfs_ops	= &sysfs_ops,
  };

  int sysdev_create_file(struct sys_device *s, struct sysdev_attribute *a)

  {
  	return sysfs_create_file(&s->kobj, &a->attr);
  }

  void sysdev_remove_file(struct sys_device *s, struct sysdev_attribute *a)

  {
  	sysfs_remove_file(&s->kobj, &a->attr);
  }
  
  EXPORT_SYMBOL_GPL(sysdev_create_file);
  EXPORT_SYMBOL_GPL(sysdev_remove_file);

  #define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
  #define to_sysdev_class_attr(a) container_of(a, \
  	struct sysdev_class_attribute, attr)
  
  static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
  				 char *buffer)
  {

  	struct sysdev_class *class = to_sysdev_class(kobj);

  	struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);
  
  	if (class_attr->show)

  		return class_attr->show(class, class_attr, buffer);

  	return -EIO;
  }
  
  static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
  				  const char *buffer, size_t count)
  {

  	struct sysdev_class *class = to_sysdev_class(kobj);
  	struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);

  
  	if (class_attr->store)

  		return class_attr->store(class, class_attr, buffer, count);

  	return -EIO;
  }

  static const struct sysfs_ops sysfs_class_ops = {

  	.show	= sysdev_class_show,
  	.store	= sysdev_class_store,
  };
  
  static struct kobj_type ktype_sysdev_class = {
  	.sysfs_ops	= &sysfs_class_ops,
  };
  
  int sysdev_class_create_file(struct sysdev_class *c,
  			     struct sysdev_class_attribute *a)
  {
  	return sysfs_create_file(&c->kset.kobj, &a->attr);
  }
  EXPORT_SYMBOL_GPL(sysdev_class_create_file);
  
  void sysdev_class_remove_file(struct sysdev_class *c,
  			      struct sysdev_class_attribute *a)
  {
  	sysfs_remove_file(&c->kset.kobj, &a->attr);
  }
  EXPORT_SYMBOL_GPL(sysdev_class_remove_file);

  extern struct kset *system_kset;

  int sysdev_class_register(struct sysdev_class *cls)

  {

  	int retval;

  	pr_debug("Registering sysdev class '%s'
  ", cls->name);

  	INIT_LIST_HEAD(&cls->drivers);

  	memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));

  	cls->kset.kobj.parent = &system_kset->kobj;

  	cls->kset.kobj.ktype = &ktype_sysdev_class;

  	cls->kset.kobj.kset = system_kset;

  	retval = kobject_set_name(&cls->kset.kobj, "%s", cls->name);

  	if (retval)
  		return retval;

  	retval = kset_register(&cls->kset);
  	if (!retval && cls->attrs)
  		retval = sysfs_create_files(&cls->kset.kobj,
  					    (const struct attribute **)cls->attrs);
  	return retval;

  }

  void sysdev_class_unregister(struct sysdev_class *cls)

  {
  	pr_debug("Unregistering sysdev class '%s'
  ",
  		 kobject_name(&cls->kset.kobj));

  	if (cls->attrs)
  		sysfs_remove_files(&cls->kset.kobj,
  				   (const struct attribute **)cls->attrs);

  	kset_unregister(&cls->kset);
  }
  
  EXPORT_SYMBOL_GPL(sysdev_class_register);
  EXPORT_SYMBOL_GPL(sysdev_class_unregister);

  static DEFINE_MUTEX(sysdev_drivers_lock);

  /*
   * @dev != NULL means that we're unwinding because some drv->add()
   * failed for some reason. You need to grab sysdev_drivers_lock before
   * calling this.
   */
  static void __sysdev_driver_remove(struct sysdev_class *cls,
  				   struct sysdev_driver *drv,
  				   struct sys_device *from_dev)
  {
  	struct sys_device *dev = from_dev;
  
  	list_del_init(&drv->entry);
  	if (!cls)
  		return;
  
  	if (!drv->remove)
  		goto kset_put;
  
  	if (dev)
  		list_for_each_entry_continue_reverse(dev, &cls->kset.list,
  						     kobj.entry)
  			drv->remove(dev);
  	else
  		list_for_each_entry(dev, &cls->kset.list, kobj.entry)
  			drv->remove(dev);
  
  kset_put:
  	kset_put(&cls->kset);
  }

  /**

   *	sysdev_driver_register - Register auxiliary driver

   *	@cls:	Device class driver belongs to.

   *	@drv:	Driver.
   *

   *	@drv is inserted into @cls->drivers to be

   *	called on each operation on devices of that class. The refcount
   *	of @cls is incremented.

   */

  int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)

  {

  	struct sys_device *dev = NULL;

  	int err = 0;

  	if (!cls) {

  		WARN(1, KERN_WARNING "sysdev: invalid class passed to %s!
  ",
  			__func__);

  		return -EINVAL;
  	}
  
  	/* Check whether this driver has already been added to a class. */

  	if (drv->entry.next && !list_empty(&drv->entry))
  		WARN(1, KERN_WARNING "sysdev: class %s: driver (%p) has already"

  			" been registered to a class, something is wrong, but "
  			"will forge on!
  ", cls->name, drv);

  	mutex_lock(&sysdev_drivers_lock);

  	if (cls && kset_get(&cls->kset)) {
  		list_add_tail(&drv->entry, &cls->drivers);
  
  		/* If devices of this class already exist, tell the driver */
  		if (drv->add) {

  			list_for_each_entry(dev, &cls->kset.list, kobj.entry) {
  				err = drv->add(dev);
  				if (err)
  					goto unwind;
  			}

  		}

  	} else {
  		err = -EINVAL;

  		WARN(1, KERN_ERR "%s: invalid device class
  ", __func__);

  	}

  
  	goto unlock;
  
  unwind:
  	__sysdev_driver_remove(cls, drv, dev);
  
  unlock:

  	mutex_unlock(&sysdev_drivers_lock);

  	return err;

  }

  /**

   *	sysdev_driver_unregister - Remove an auxiliary driver.

   *	@cls:	Class driver belongs to.
   *	@drv:	Driver.
   */

  void sysdev_driver_unregister(struct sysdev_class *cls,
  			      struct sysdev_driver *drv)

  {

  	mutex_lock(&sysdev_drivers_lock);

  	__sysdev_driver_remove(cls, drv, NULL);

  	mutex_unlock(&sysdev_drivers_lock);

  }

  EXPORT_SYMBOL_GPL(sysdev_driver_register);
  EXPORT_SYMBOL_GPL(sysdev_driver_unregister);

  /**
   *	sysdev_register - add a system device to the tree
   *	@sysdev:	device in question
   *
   */

  int sysdev_register(struct sys_device *sysdev)

  {
  	int error;

  	struct sysdev_class *cls = sysdev->cls;

  
  	if (!cls)
  		return -EINVAL;

  	pr_debug("Registering sys device of class '%s'
  ",
  		 kobject_name(&cls->kset.kobj));

  	/* initialize the kobject to 0, in case it had previously been used */
  	memset(&sysdev->kobj, 0x00, sizeof(struct kobject));

  	/* Make sure the kset is set */
  	sysdev->kobj.kset = &cls->kset;

  	/* Register the object */

  	error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
  				     "%s%d", kobject_name(&cls->kset.kobj),
  				     sysdev->id);

  
  	if (!error) {

  		struct sysdev_driver *drv;

  		pr_debug("Registering sys device '%s'
  ",
  			 kobject_name(&sysdev->kobj));

  		mutex_lock(&sysdev_drivers_lock);

  		/* Generic notification is implicit, because it's that
  		 * code that should have called us.
  		 */

  		/* Notify class auxiliary drivers */

  		list_for_each_entry(drv, &cls->drivers, entry) {
  			if (drv->add)
  				drv->add(sysdev);
  		}

  		mutex_unlock(&sysdev_drivers_lock);

  		kobject_uevent(&sysdev->kobj, KOBJ_ADD);

  	}

  	return error;
  }

  void sysdev_unregister(struct sys_device *sysdev)

  {

  	struct sysdev_driver *drv;

  	mutex_lock(&sysdev_drivers_lock);

  	list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
  		if (drv->remove)
  			drv->remove(sysdev);
  	}

  	mutex_unlock(&sysdev_drivers_lock);

  	kobject_put(&sysdev->kobj);

  }

  EXPORT_SYMBOL_GPL(sysdev_register);
  EXPORT_SYMBOL_GPL(sysdev_unregister);

  #define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)
  
  ssize_t sysdev_store_ulong(struct sys_device *sysdev,
  			   struct sysdev_attribute *attr,
  			   const char *buf, size_t size)
  {
  	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
  	char *end;
  	unsigned long new = simple_strtoul(buf, &end, 0);
  	if (end == buf)
  		return -EINVAL;
  	*(unsigned long *)(ea->var) = new;

  	/* Always return full write size even if we didn't consume all */
  	return size;

  }
  EXPORT_SYMBOL_GPL(sysdev_store_ulong);
  
  ssize_t sysdev_show_ulong(struct sys_device *sysdev,
  			  struct sysdev_attribute *attr,
  			  char *buf)
  {
  	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
  	return snprintf(buf, PAGE_SIZE, "%lx
  ", *(unsigned long *)(ea->var));
  }
  EXPORT_SYMBOL_GPL(sysdev_show_ulong);
  
  ssize_t sysdev_store_int(struct sys_device *sysdev,
  			   struct sysdev_attribute *attr,
  			   const char *buf, size_t size)
  {
  	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
  	char *end;
  	long new = simple_strtol(buf, &end, 0);
  	if (end == buf || new > INT_MAX || new < INT_MIN)
  		return -EINVAL;
  	*(int *)(ea->var) = new;

  	/* Always return full write size even if we didn't consume all */
  	return size;

  }
  EXPORT_SYMBOL_GPL(sysdev_store_int);
  
  ssize_t sysdev_show_int(struct sys_device *sysdev,
  			  struct sysdev_attribute *attr,
  			  char *buf)
  {
  	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
  	return snprintf(buf, PAGE_SIZE, "%d
  ", *(int *)(ea->var));
  }
  EXPORT_SYMBOL_GPL(sysdev_show_int);