// SPDX-License-Identifier: GPL-2.0 /* * 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 sysfs_emit(buf, "%04x:%02x\n", pci_domain_nr(slot->bus), slot->bus->number); return sysfs_emit(buf, "%04x:%02x:%02x\n", pci_domain_nr(slot->bus), slot->bus->number, slot->number); } static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf) { return sysfs_emit(buf, "%s\n", pci_speed_string(speed)); } 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\n", slot->number, pci_slot_name(slot)); down_read(&pci_bus_sem); list_for_each_entry(dev, &slot->bus->devices, bus_list) if (PCI_SLOT(dev->devfn) == slot->number) dev->slot = NULL; up_read(&pci_bus_sem); list_del(&slot->list); kfree(slot); } static struct pci_slot_attribute pci_slot_attr_address = __ATTR(address, S_IRUGO, address_read_file, NULL); static struct pci_slot_attribute pci_slot_attr_max_speed = __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL); static struct pci_slot_attribute pci_slot_attr_cur_speed = __ATTR(cur_bus_speed, 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, }; ATTRIBUTE_GROUPS(pci_slot_default); static struct kobj_type pci_slot_ktype = { .sysfs_ops = &pci_slot_sysfs_ops, .release = &pci_slot_release, .default_groups = pci_slot_default_groups, }; 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; } void pci_dev_assign_slot(struct pci_dev *dev) { struct pci_slot *slot; mutex_lock(&pci_slot_mutex); list_for_each_entry(slot, &dev->bus->slots, list) if (PCI_SLOT(dev->devfn) == slot->number) dev->slot = slot; mutex_unlock(&pci_slot_mutex); } static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr) { struct pci_slot *slot; /* We already hold pci_slot_mutex */ 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; mutex_lock(&pci_slot_mutex); 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; kfree(slot); goto err; } INIT_LIST_HEAD(&slot->list); list_add(&slot->list, &parent->slots); err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL, "%s", slot_name); if (err) { kobject_put(&slot->kobj); goto err; } down_read(&pci_bus_sem); list_for_each_entry(dev, &parent->devices, bus_list) if (PCI_SLOT(dev->devfn) == slot_nr) dev->slot = slot; up_read(&pci_bus_sem); dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n", slot_nr, pci_slot_name(slot)); out: kfree(slot_name); mutex_unlock(&pci_slot_mutex); return slot; err: slot = ERR_PTR(err); goto out; } EXPORT_SYMBOL_GPL(pci_create_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, kref_read(&slot->kobj.kref) - 1); mutex_lock(&pci_slot_mutex); kobject_put(&slot->kobj); mutex_unlock(&pci_slot_mutex); } EXPORT_SYMBOL_GPL(pci_destroy_slot); #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE) #include <linux/pci_hotplug.h> /** * pci_hp_create_module_link - create symbolic link to 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 ret; if (!slot || !slot->ops) return; kobj = kset_find_obj(module_kset, slot->mod_name); if (!kobj) return; ret = sysfs_create_link(&pci_slot->kobj, kobj, "module"); if (ret) dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n", ret); kobject_put(kobj); } EXPORT_SYMBOL_GPL(pci_hp_create_module_link); /** * pci_hp_remove_module_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) { pr_err("PCI: Slot initialization failure\n"); return -ENOMEM; } return 0; } subsys_initcall(pci_slot_init);