drivers/pci/slot.c - maze/linux - Git at Google

 /*
  * drivers/pci/slot.c
  * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>
  * Copyright (C) 2006-2008 Hewlett-Packard Development Company, L.P.
  * 	Alex Chiang <achiang@hp.com>
  */

 #include <linux/kobject.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 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\n",
 				pci_domain_nr(slot->bus),
 				slot->bus->number);
 	else
 		return sprintf(buf, "%04x:%02x:%02x\n",
 				pci_domain_nr(slot->bus),
 				slot->bus->number,
 				slot->number);
 }

 static void pci_slot_release(struct kobject *kobj)
 {
 	struct pci_dev *dev;
 	struct pci_slot *slot = to_pci_slot(kobj);

 	pr_debug("%s: releasing pci_slot on %x:%d\n", __func__,
 		 slot->bus->number, slot->number);

 	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 attribute *pci_slot_default_attrs[] = {
 	&pci_slot_attr_address.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(kobject_name(&slot->kobj), 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;

 	/* Don't care if debug printk has a -1 for slot_nr */
 	pr_debug("%s: created pci_slot on %04x:%02x:%02x\n",
 		 __func__, pci_domain_nr(parent), parent->number, slot_nr);

 out:
 	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)
 {
 	pr_debug("%s: dec refcount to %d on %04x:%02x:%02x\n", __func__,
 		 atomic_read(&slot->kobj.kref.refcount) - 1,
 		 pci_domain_nr(slot->bus), slot->bus->number, slot->number);

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

 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\n");
 		return -ENOMEM;
 	}
 	return 0;
 }

 subsys_initcall(pci_slot_init);
	/*
	* drivers/pci/slot.c
	* Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>
	* Copyright (C) 2006-2008 Hewlett-Packard Development Company, L.P.
	* Alex Chiang <achiang@hp.com>
	*/

	#include <linux/kobject.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 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\n",
	pci_domain_nr(slot->bus),
	slot->bus->number);
	else
	return sprintf(buf, "%04x:%02x:%02x\n",
	pci_domain_nr(slot->bus),
	slot->bus->number,
	slot->number);
	}

	static void pci_slot_release(struct kobject *kobj)
	{
	struct pci_dev *dev;
	struct pci_slot *slot = to_pci_slot(kobj);

	pr_debug("%s: releasing pci_slot on %x:%d\n", __func__,
	slot->bus->number, slot->number);

	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 attribute *pci_slot_default_attrs[] = {
	&pci_slot_attr_address.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(kobject_name(&slot->kobj), 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;

	/* Don't care if debug printk has a -1 for slot_nr */
	pr_debug("%s: created pci_slot on %04x:%02x:%02x\n",
	__func__, pci_domain_nr(parent), parent->number, slot_nr);

	out:
	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)
	{
	pr_debug("%s: dec refcount to %d on %04x:%02x:%02x\n", __func__,
	atomic_read(&slot->kobj.kref.refcount) - 1,
	pci_domain_nr(slot->bus), slot->bus->number, slot->number);

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

	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\n");
	return -ENOMEM;
	}
	return 0;
	}

	subsys_initcall(pci_slot_init);