linux/drivers/pci/slot.c
Kenji Kaneshige c825bc94c8 PCI hotplug: create symlink to hotplug driver module
Create symbolic link to hotplug driver module in the PCI slot
directory (/sys/bus/pci/slots/<SLOT#>). In the past, we need to load
hotplug drivers one by one to identify the hotplug driver that handles
the slot, and it was very inconvenient especially for trouble shooting.
With this change, we can easily identify the hotplug driver.

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-16 14:30:11 -07:00

364 lines
9.2 KiB
C

/*
* 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/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);
dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
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 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(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\n",
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\n",
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.
* @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.
* @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\n");
return -ENOMEM;
}
return 0;
}
subsys_initcall(pci_slot_init);