// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>
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* Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P.
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* Alex Chiang <achiang@hp.com>
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*/
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#include <linux/kobject.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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#include <linux/pci.h>
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#include <linux/err.h>
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#include "pci.h"
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struct kset *pci_slots_kset;
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EXPORT_SYMBOL_GPL(pci_slots_kset);
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static ssize_t pci_slot_attr_show(struct kobject *kobj,
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struct attribute *attr, char *buf)
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{
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struct pci_slot *slot = to_pci_slot(kobj);
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struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
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return attribute->show ? attribute->show(slot, buf) : -EIO;
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}
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static ssize_t pci_slot_attr_store(struct kobject *kobj,
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struct attribute *attr, const char *buf, size_t len)
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{
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struct pci_slot *slot = to_pci_slot(kobj);
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struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
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return attribute->store ? attribute->store(slot, buf, len) : -EIO;
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}
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static const struct sysfs_ops pci_slot_sysfs_ops = {
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.show = pci_slot_attr_show,
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.store = pci_slot_attr_store,
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};
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static ssize_t address_read_file(struct pci_slot *slot, char *buf)
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{
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if (slot->number == 0xff)
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return sprintf(buf, "%04x:%02x\n",
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pci_domain_nr(slot->bus),
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slot->bus->number);
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else
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return sprintf(buf, "%04x:%02x:%02x\n",
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pci_domain_nr(slot->bus),
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slot->bus->number,
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slot->number);
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}
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static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
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{
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return sprintf(buf, "%s\n", pci_speed_string(speed));
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}
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static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
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{
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return bus_speed_read(slot->bus->max_bus_speed, buf);
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}
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static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
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{
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return bus_speed_read(slot->bus->cur_bus_speed, buf);
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}
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static void pci_slot_release(struct kobject *kobj)
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{
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struct pci_dev *dev;
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struct pci_slot *slot = to_pci_slot(kobj);
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dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
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slot->number, pci_slot_name(slot));
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down_read(&pci_bus_sem);
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list_for_each_entry(dev, &slot->bus->devices, bus_list)
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if (PCI_SLOT(dev->devfn) == slot->number)
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dev->slot = NULL;
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up_read(&pci_bus_sem);
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list_del(&slot->list);
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kfree(slot);
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}
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static struct pci_slot_attribute pci_slot_attr_address =
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__ATTR(address, S_IRUGO, address_read_file, NULL);
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static struct pci_slot_attribute pci_slot_attr_max_speed =
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__ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
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static struct pci_slot_attribute pci_slot_attr_cur_speed =
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__ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
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static struct attribute *pci_slot_default_attrs[] = {
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&pci_slot_attr_address.attr,
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&pci_slot_attr_max_speed.attr,
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&pci_slot_attr_cur_speed.attr,
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NULL,
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};
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static struct kobj_type pci_slot_ktype = {
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.sysfs_ops = &pci_slot_sysfs_ops,
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.release = &pci_slot_release,
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.default_attrs = pci_slot_default_attrs,
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};
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static char *make_slot_name(const char *name)
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{
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char *new_name;
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int len, max, dup;
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new_name = kstrdup(name, GFP_KERNEL);
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if (!new_name)
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return NULL;
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/*
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* Make sure we hit the realloc case the first time through the
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* loop. 'len' will be strlen(name) + 3 at that point which is
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* enough space for "name-X" and the trailing NUL.
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*/
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len = strlen(name) + 2;
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max = 1;
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dup = 1;
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for (;;) {
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struct kobject *dup_slot;
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dup_slot = kset_find_obj(pci_slots_kset, new_name);
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if (!dup_slot)
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break;
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kobject_put(dup_slot);
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if (dup == max) {
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len++;
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max *= 10;
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kfree(new_name);
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new_name = kmalloc(len, GFP_KERNEL);
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if (!new_name)
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break;
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}
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sprintf(new_name, "%s-%d", name, dup++);
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}
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return new_name;
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}
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static int rename_slot(struct pci_slot *slot, const char *name)
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{
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int result = 0;
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char *slot_name;
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if (strcmp(pci_slot_name(slot), name) == 0)
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return result;
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slot_name = make_slot_name(name);
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if (!slot_name)
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return -ENOMEM;
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result = kobject_rename(&slot->kobj, slot_name);
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kfree(slot_name);
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return result;
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}
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void pci_dev_assign_slot(struct pci_dev *dev)
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{
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struct pci_slot *slot;
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mutex_lock(&pci_slot_mutex);
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list_for_each_entry(slot, &dev->bus->slots, list)
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if (PCI_SLOT(dev->devfn) == slot->number)
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dev->slot = slot;
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mutex_unlock(&pci_slot_mutex);
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}
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static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
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{
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struct pci_slot *slot;
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/* We already hold pci_slot_mutex */
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list_for_each_entry(slot, &parent->slots, list)
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if (slot->number == slot_nr) {
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kobject_get(&slot->kobj);
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return slot;
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}
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return NULL;
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}
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/**
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* pci_create_slot - create or increment refcount for physical PCI slot
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* @parent: struct pci_bus of parent bridge
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* @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
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* @name: user visible string presented in /sys/bus/pci/slots/<name>
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* @hotplug: set if caller is hotplug driver, NULL otherwise
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*
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* PCI slots have first class attributes such as address, speed, width,
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* and a &struct pci_slot is used to manage them. This interface will
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* either return a new &struct pci_slot to the caller, or if the pci_slot
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* already exists, its refcount will be incremented.
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*
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* Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
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*
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* There are known platforms with broken firmware that assign the same
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* name to multiple slots. Workaround these broken platforms by renaming
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* the slots on behalf of the caller. If firmware assigns name N to
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* multiple slots:
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*
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* The first slot is assigned N
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* The second slot is assigned N-1
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* The third slot is assigned N-2
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* etc.
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*
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* Placeholder slots:
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* In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
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* a slot. There is one notable exception - pSeries (rpaphp), where the
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* @slot_nr cannot be determined until a device is actually inserted into
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* the slot. In this scenario, the caller may pass -1 for @slot_nr.
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*
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* The following semantics are imposed when the caller passes @slot_nr ==
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* -1. First, we no longer check for an existing %struct pci_slot, as there
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* may be many slots with @slot_nr of -1. The other change in semantics is
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* user-visible, which is the 'address' parameter presented in sysfs will
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* consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
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* %struct pci_bus and bb is the bus number. In other words, the devfn of
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* the 'placeholder' slot will not be displayed.
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*/
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struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
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const char *name,
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struct hotplug_slot *hotplug)
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{
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struct pci_dev *dev;
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struct pci_slot *slot;
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int err = 0;
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char *slot_name = NULL;
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mutex_lock(&pci_slot_mutex);
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if (slot_nr == -1)
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goto placeholder;
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/*
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* Hotplug drivers are allowed to rename an existing slot,
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* but only if not already claimed.
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*/
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slot = get_slot(parent, slot_nr);
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if (slot) {
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if (hotplug) {
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if ((err = slot->hotplug ? -EBUSY : 0)
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|| (err = rename_slot(slot, name))) {
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kobject_put(&slot->kobj);
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slot = NULL;
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goto err;
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}
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}
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goto out;
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}
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placeholder:
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slot = kzalloc(sizeof(*slot), GFP_KERNEL);
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if (!slot) {
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err = -ENOMEM;
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goto err;
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}
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slot->bus = parent;
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slot->number = slot_nr;
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slot->kobj.kset = pci_slots_kset;
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slot_name = make_slot_name(name);
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if (!slot_name) {
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err = -ENOMEM;
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kfree(slot);
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goto err;
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}
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INIT_LIST_HEAD(&slot->list);
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list_add(&slot->list, &parent->slots);
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err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
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"%s", slot_name);
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if (err) {
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kobject_put(&slot->kobj);
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goto err;
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}
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down_read(&pci_bus_sem);
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list_for_each_entry(dev, &parent->devices, bus_list)
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if (PCI_SLOT(dev->devfn) == slot_nr)
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dev->slot = slot;
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up_read(&pci_bus_sem);
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dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
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slot_nr, pci_slot_name(slot));
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out:
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kfree(slot_name);
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mutex_unlock(&pci_slot_mutex);
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return slot;
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err:
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slot = ERR_PTR(err);
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goto out;
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}
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EXPORT_SYMBOL_GPL(pci_create_slot);
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/**
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* pci_destroy_slot - decrement refcount for physical PCI slot
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* @slot: struct pci_slot to decrement
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*
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* %struct pci_slot is refcounted, so destroying them is really easy; we
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* just call kobject_put on its kobj and let our release methods do the
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* rest.
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*/
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void pci_destroy_slot(struct pci_slot *slot)
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{
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dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
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slot->number, kref_read(&slot->kobj.kref) - 1);
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mutex_lock(&pci_slot_mutex);
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kobject_put(&slot->kobj);
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mutex_unlock(&pci_slot_mutex);
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}
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EXPORT_SYMBOL_GPL(pci_destroy_slot);
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#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
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#include <linux/pci_hotplug.h>
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/**
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* pci_hp_create_link - create symbolic link to the hotplug driver module.
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* @pci_slot: struct pci_slot
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*
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* Helper function for pci_hotplug_core.c to create symbolic link to
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* the hotplug driver module.
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*/
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void pci_hp_create_module_link(struct pci_slot *pci_slot)
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{
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struct hotplug_slot *slot = pci_slot->hotplug;
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struct kobject *kobj = NULL;
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int ret;
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if (!slot || !slot->ops)
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return;
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kobj = kset_find_obj(module_kset, slot->mod_name);
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if (!kobj)
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return;
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ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
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if (ret)
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dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
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ret);
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kobject_put(kobj);
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}
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EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
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/**
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* pci_hp_remove_link - remove symbolic link to the hotplug driver module.
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* @pci_slot: struct pci_slot
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*
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* Helper function for pci_hotplug_core.c to remove symbolic link to
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* the hotplug driver module.
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*/
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void pci_hp_remove_module_link(struct pci_slot *pci_slot)
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{
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sysfs_remove_link(&pci_slot->kobj, "module");
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}
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EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
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#endif
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static int pci_slot_init(void)
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{
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struct kset *pci_bus_kset;
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pci_bus_kset = bus_get_kset(&pci_bus_type);
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pci_slots_kset = kset_create_and_add("slots", NULL,
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&pci_bus_kset->kobj);
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if (!pci_slots_kset) {
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pr_err("PCI: Slot initialization failure\n");
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return -ENOMEM;
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}
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return 0;
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}
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subsys_initcall(pci_slot_init);
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