/*
* 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_slot *slot = to_pci_slot(kobj);
pr_debug("%s: releasing pci_slot on %x:%d\n", __func__,
slot->bus->number, slot->number);
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,
};
/**
* 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>
*
* 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, @name tuple.
*
* 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, the check for existing %struct pci_slot is skipped, as the
* caller may know about several unpopulated slots on a given %struct
* pci_bus, and each slot would have a @slot_nr of -1. Uniqueness for
* these slots is then determined by the @name parameter. We expect
* kobject_init_and_add() to warn us if the caller attempts to create
* multiple slots with the same name. 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 pci_slot *slot;
int err;
down_write(&pci_bus_sem);
if (slot_nr == -1)
goto placeholder;
/* If we've already created this slot, bump refcount and return. */
list_for_each_entry(slot, &parent->slots, list) {
if (slot->number == slot_nr) {
kobject_get(&slot->kobj);
pr_debug("%s: inc refcount to %d on %04x:%02x:%02x\n",
__func__,
atomic_read(&slot->kobj.kref.refcount),
pci_domain_nr(parent), parent->number,
slot_nr);
goto out;
}
}
placeholder:
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot) {
slot = ERR_PTR(-ENOMEM);
goto out;
}
slot->bus = parent;
slot->number = slot_nr;
slot->kobj.kset = pci_slots_kset;
err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
"%s", name);
if (err) {
printk(KERN_ERR "Unable to register kobject %s\n", name);
goto err;
}
INIT_LIST_HEAD(&slot->list);
list_add(&slot->list, &parent->slots);
/* 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_update_slot_number - 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_update_slot_number(struct pci_slot *slot, int slot_nr)
{
int name_count = 0;
struct pci_slot *tmp;
down_write(&pci_bus_sem);
list_for_each_entry(tmp, &slot->bus->slots, list) {
WARN_ON(tmp->number == slot_nr);
if (!strcmp(kobject_name(&tmp->kobj), kobject_name(&slot->kobj)))
name_count++;
}
if (name_count > 1)
printk(KERN_WARNING "pci_update_slot_number found %d slots with the same name: %s\n", name_count, kobject_name(&slot->kobj));
slot->number = slot_nr;
up_write(&pci_bus_sem);
}
EXPORT_SYMBOL_GPL(pci_update_slot_number);
/**
* 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);
