/*
   * drivers/pci/slot.c
   * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>

   * Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P.
   *	Alex Chiang <achiang@hp.com>

   */
  
  #include <linux/kobject.h>

  #include <linux/slab.h>

  #include <linux/module.h>

  #include <linux/pci.h>
  #include <linux/err.h>
  #include "pci.h"
  
  struct kset *pci_slots_kset;
  EXPORT_SYMBOL_GPL(pci_slots_kset);
  
  static ssize_t pci_slot_attr_show(struct kobject *kobj,
  					struct attribute *attr, char *buf)
  {
  	struct pci_slot *slot = to_pci_slot(kobj);
  	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
  	return attribute->show ? attribute->show(slot, buf) : -EIO;
  }
  
  static ssize_t pci_slot_attr_store(struct kobject *kobj,
  			struct attribute *attr, const char *buf, size_t len)
  {
  	struct pci_slot *slot = to_pci_slot(kobj);
  	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
  	return attribute->store ? attribute->store(slot, buf, len) : -EIO;
  }

  static const struct sysfs_ops pci_slot_sysfs_ops = {

  	.show = pci_slot_attr_show,
  	.store = pci_slot_attr_store,
  };
  
  static ssize_t address_read_file(struct pci_slot *slot, char *buf)
  {
  	if (slot->number == 0xff)
  		return sprintf(buf, "%04x:%02x
  ",
  				pci_domain_nr(slot->bus),
  				slot->bus->number);
  	else
  		return sprintf(buf, "%04x:%02x:%02x
  ",
  				pci_domain_nr(slot->bus),
  				slot->bus->number,
  				slot->number);
  }

  /* these strings match up with the values in pci_bus_speed */

  static const char *pci_bus_speed_strings[] = {

  	"33 MHz PCI",		/* 0x00 */
  	"66 MHz PCI",		/* 0x01 */
  	"66 MHz PCI-X", 	/* 0x02 */
  	"100 MHz PCI-X",	/* 0x03 */
  	"133 MHz PCI-X",	/* 0x04 */
  	NULL,			/* 0x05 */
  	NULL,			/* 0x06 */
  	NULL,			/* 0x07 */
  	NULL,			/* 0x08 */
  	"66 MHz PCI-X 266",	/* 0x09 */
  	"100 MHz PCI-X 266",	/* 0x0a */
  	"133 MHz PCI-X 266",	/* 0x0b */

  	"Unknown AGP",		/* 0x0c */
  	"1x AGP",		/* 0x0d */
  	"2x AGP",		/* 0x0e */
  	"4x AGP",		/* 0x0f */
  	"8x AGP",		/* 0x10 */

  	"66 MHz PCI-X 533",	/* 0x11 */
  	"100 MHz PCI-X 533",	/* 0x12 */
  	"133 MHz PCI-X 533",	/* 0x13 */
  	"2.5 GT/s PCIe",	/* 0x14 */
  	"5.0 GT/s PCIe",	/* 0x15 */

  	"8.0 GT/s PCIe",	/* 0x16 */

  };
  
  static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
  {
  	const char *speed_string;
  
  	if (speed < ARRAY_SIZE(pci_bus_speed_strings))
  		speed_string = pci_bus_speed_strings[speed];
  	else
  		speed_string = "Unknown";
  
  	return sprintf(buf, "%s
  ", speed_string);
  }
  
  static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
  {
  	return bus_speed_read(slot->bus->max_bus_speed, buf);
  }
  
  static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
  {
  	return bus_speed_read(slot->bus->cur_bus_speed, buf);
  }

  static void pci_slot_release(struct kobject *kobj)
  {

  	struct pci_dev *dev;

  	struct pci_slot *slot = to_pci_slot(kobj);

  	dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s
  ",
  		slot->number, pci_slot_name(slot));

  	list_for_each_entry(dev, &slot->bus->devices, bus_list)
  		if (PCI_SLOT(dev->devfn) == slot->number)
  			dev->slot = NULL;

  	list_del(&slot->list);
  
  	kfree(slot);
  }
  
  static struct pci_slot_attribute pci_slot_attr_address =
  	__ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);

  static struct pci_slot_attribute pci_slot_attr_max_speed =
  	__ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
  static struct pci_slot_attribute pci_slot_attr_cur_speed =
  	__ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);

  
  static struct attribute *pci_slot_default_attrs[] = {
  	&pci_slot_attr_address.attr,

  	&pci_slot_attr_max_speed.attr,
  	&pci_slot_attr_cur_speed.attr,

  	NULL,
  };
  
  static struct kobj_type pci_slot_ktype = {
  	.sysfs_ops = &pci_slot_sysfs_ops,
  	.release = &pci_slot_release,
  	.default_attrs = pci_slot_default_attrs,
  };

  static char *make_slot_name(const char *name)
  {
  	char *new_name;
  	int len, max, dup;
  
  	new_name = kstrdup(name, GFP_KERNEL);
  	if (!new_name)
  		return NULL;
  
  	/*
  	 * Make sure we hit the realloc case the first time through the
  	 * loop.  'len' will be strlen(name) + 3 at that point which is
  	 * enough space for "name-X" and the trailing NUL.
  	 */
  	len = strlen(name) + 2;
  	max = 1;
  	dup = 1;
  
  	for (;;) {
  		struct kobject *dup_slot;
  		dup_slot = kset_find_obj(pci_slots_kset, new_name);
  		if (!dup_slot)
  			break;
  		kobject_put(dup_slot);
  		if (dup == max) {
  			len++;
  			max *= 10;
  			kfree(new_name);
  			new_name = kmalloc(len, GFP_KERNEL);
  			if (!new_name)
  				break;
  		}
  		sprintf(new_name, "%s-%d", name, dup++);
  	}
  
  	return new_name;
  }
  
  static int rename_slot(struct pci_slot *slot, const char *name)
  {
  	int result = 0;
  	char *slot_name;

  	if (strcmp(pci_slot_name(slot), name) == 0)

  		return result;
  
  	slot_name = make_slot_name(name);
  	if (!slot_name)
  		return -ENOMEM;
  
  	result = kobject_rename(&slot->kobj, slot_name);
  	kfree(slot_name);
  
  	return result;
  }
  
  static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
  {
  	struct pci_slot *slot;
  	/*
  	 * We already hold pci_bus_sem so don't worry
  	 */
  	list_for_each_entry(slot, &parent->slots, list)
  		if (slot->number == slot_nr) {
  			kobject_get(&slot->kobj);
  			return slot;
  		}
  
  	return NULL;
  }

  /**
   * pci_create_slot - create or increment refcount for physical PCI slot
   * @parent: struct pci_bus of parent bridge
   * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
   * @name: user visible string presented in /sys/bus/pci/slots/<name>

   * @hotplug: set if caller is hotplug driver, NULL otherwise

   *
   * PCI slots have first class attributes such as address, speed, width,
   * and a &struct pci_slot is used to manage them. This interface will
   * either return a new &struct pci_slot to the caller, or if the pci_slot
   * already exists, its refcount will be incremented.
   *

   * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
   *
   * There are known platforms with broken firmware that assign the same
   * name to multiple slots. Workaround these broken platforms by renaming
   * the slots on behalf of the caller. If firmware assigns name N to
   * multiple slots:
   *
   * The first slot is assigned N
   * The second slot is assigned N-1
   * The third slot is assigned N-2
   * etc.

   *
   * Placeholder slots:
   * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
   * a slot. There is one notable exception - pSeries (rpaphp), where the
   * @slot_nr cannot be determined until a device is actually inserted into
   * the slot. In this scenario, the caller may pass -1 for @slot_nr.
   *
   * The following semantics are imposed when the caller passes @slot_nr ==

   * -1. First, we no longer check for an existing %struct pci_slot, as there
   * may be many slots with @slot_nr of -1.  The other change in semantics is

   * user-visible, which is the 'address' parameter presented in sysfs will
   * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
   * %struct pci_bus and bb is the bus number. In other words, the devfn of
   * the 'placeholder' slot will not be displayed.
   */

  struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,

  				 const char *name,
  				 struct hotplug_slot *hotplug)

  {

  	struct pci_dev *dev;

  	struct pci_slot *slot;

  	int err = 0;
  	char *slot_name = NULL;

  
  	down_write(&pci_bus_sem);
  
  	if (slot_nr == -1)
  		goto placeholder;

  	/*
  	 * Hotplug drivers are allowed to rename an existing slot,
  	 * but only if not already claimed.
  	 */
  	slot = get_slot(parent, slot_nr);
  	if (slot) {
  		if (hotplug) {
  			if ((err = slot->hotplug ? -EBUSY : 0)
  			     || (err = rename_slot(slot, name))) {
  				kobject_put(&slot->kobj);
  				slot = NULL;
  				goto err;
  			}

  		}

  		goto out;

  	}
  
  placeholder:
  	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
  	if (!slot) {

  		err = -ENOMEM;
  		goto err;

  	}
  
  	slot->bus = parent;
  	slot->number = slot_nr;
  
  	slot->kobj.kset = pci_slots_kset;

  
  	slot_name = make_slot_name(name);
  	if (!slot_name) {
  		err = -ENOMEM;

  		goto err;
  	}

  	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
  				   "%s", slot_name);
  	if (err)
  		goto err;

  	INIT_LIST_HEAD(&slot->list);
  	list_add(&slot->list, &parent->slots);

  	list_for_each_entry(dev, &parent->devices, bus_list)
  		if (PCI_SLOT(dev->devfn) == slot_nr)
  			dev->slot = slot;

  	dev_dbg(&parent->dev, "dev %02x, created physical slot %s
  ",
  		slot_nr, pci_slot_name(slot));

  out:

  	kfree(slot_name);

  	up_write(&pci_bus_sem);
  	return slot;

  err:

  	kfree(slot);
  	slot = ERR_PTR(err);
  	goto out;
  }
  EXPORT_SYMBOL_GPL(pci_create_slot);
  
  /**

   * pci_renumber_slot - update %struct pci_slot -> number

   * @slot: &struct pci_slot to update
   * @slot_nr: new number for slot

   *
   * The primary purpose of this interface is to allow callers who earlier
   * created a placeholder slot in pci_create_slot() by passing a -1 as
   * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
   */

  void pci_renumber_slot(struct pci_slot *slot, int slot_nr)

  {

  	struct pci_slot *tmp;
  
  	down_write(&pci_bus_sem);
  
  	list_for_each_entry(tmp, &slot->bus->slots, list) {
  		WARN_ON(tmp->number == slot_nr);

  		goto out;

  	}

  	slot->number = slot_nr;

  out:

  	up_write(&pci_bus_sem);
  }

  EXPORT_SYMBOL_GPL(pci_renumber_slot);

  
  /**
   * pci_destroy_slot - decrement refcount for physical PCI slot
   * @slot: struct pci_slot to decrement
   *
   * %struct pci_slot is refcounted, so destroying them is really easy; we
   * just call kobject_put on its kobj and let our release methods do the
   * rest.
   */

  void pci_destroy_slot(struct pci_slot *slot)
  {

  	dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d
  ",
  		slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);

  
  	down_write(&pci_bus_sem);
  	kobject_put(&slot->kobj);
  	up_write(&pci_bus_sem);
  }
  EXPORT_SYMBOL_GPL(pci_destroy_slot);

  #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
  #include <linux/pci_hotplug.h>
  /**
   * pci_hp_create_link - create symbolic link to the hotplug driver module.

   * @pci_slot: struct pci_slot

   *
   * Helper function for pci_hotplug_core.c to create symbolic link to
   * the hotplug driver module.
   */
  void pci_hp_create_module_link(struct pci_slot *pci_slot)
  {
  	struct hotplug_slot *slot = pci_slot->hotplug;
  	struct kobject *kobj = NULL;
  	int no_warn;
  
  	if (!slot || !slot->ops)
  		return;
  	kobj = kset_find_obj(module_kset, slot->ops->mod_name);
  	if (!kobj)
  		return;
  	no_warn = sysfs_create_link(&pci_slot->kobj, kobj, "module");
  	kobject_put(kobj);
  }
  EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
  
  /**
   * pci_hp_remove_link - remove symbolic link to the hotplug driver module.

   * @pci_slot: struct pci_slot

   *
   * Helper function for pci_hotplug_core.c to remove symbolic link to
   * the hotplug driver module.
   */
  void pci_hp_remove_module_link(struct pci_slot *pci_slot)
  {
  	sysfs_remove_link(&pci_slot->kobj, "module");
  }
  EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
  #endif

  static int pci_slot_init(void)
  {
  	struct kset *pci_bus_kset;
  
  	pci_bus_kset = bus_get_kset(&pci_bus_type);
  	pci_slots_kset = kset_create_and_add("slots", NULL,
  						&pci_bus_kset->kobj);
  	if (!pci_slots_kset) {
  		printk(KERN_ERR "PCI: Slot initialization failure
  ");
  		return -ENOMEM;
  	}
  	return 0;
  }
  
  subsys_initcall(pci_slot_init);