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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>4 * Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P.5 * Alex Chiang <achiang@hp.com>6 */7 8#include <linux/kobject.h>9#include <linux/slab.h>10#include <linux/module.h>11#include <linux/pci.h>12#include <linux/err.h>13#include "pci.h"14 15struct kset *pci_slots_kset;16EXPORT_SYMBOL_GPL(pci_slots_kset);17 18static ssize_t pci_slot_attr_show(struct kobject *kobj,19 struct attribute *attr, char *buf)20{21 struct pci_slot *slot = to_pci_slot(kobj);22 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);23 return attribute->show ? attribute->show(slot, buf) : -EIO;24}25 26static ssize_t pci_slot_attr_store(struct kobject *kobj,27 struct attribute *attr, const char *buf, size_t len)28{29 struct pci_slot *slot = to_pci_slot(kobj);30 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);31 return attribute->store ? attribute->store(slot, buf, len) : -EIO;32}33 34static const struct sysfs_ops pci_slot_sysfs_ops = {35 .show = pci_slot_attr_show,36 .store = pci_slot_attr_store,37};38 39static ssize_t address_read_file(struct pci_slot *slot, char *buf)40{41 if (slot->number == 0xff)42 return sysfs_emit(buf, "%04x:%02x\n",43 pci_domain_nr(slot->bus),44 slot->bus->number);45 46 return sysfs_emit(buf, "%04x:%02x:%02x\n",47 pci_domain_nr(slot->bus),48 slot->bus->number,49 slot->number);50}51 52static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)53{54 return sysfs_emit(buf, "%s\n", pci_speed_string(speed));55}56 57static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)58{59 return bus_speed_read(slot->bus->max_bus_speed, buf);60}61 62static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)63{64 return bus_speed_read(slot->bus->cur_bus_speed, buf);65}66 67static void pci_slot_release(struct kobject *kobj)68{69 struct pci_dev *dev;70 struct pci_slot *slot = to_pci_slot(kobj);71 72 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",73 slot->number, pci_slot_name(slot));74 75 down_read(&pci_bus_sem);76 list_for_each_entry(dev, &slot->bus->devices, bus_list)77 if (PCI_SLOT(dev->devfn) == slot->number)78 dev->slot = NULL;79 up_read(&pci_bus_sem);80 81 list_del(&slot->list);82 83 kfree(slot);84}85 86static struct pci_slot_attribute pci_slot_attr_address =87 __ATTR(address, S_IRUGO, address_read_file, NULL);88static struct pci_slot_attribute pci_slot_attr_max_speed =89 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);90static struct pci_slot_attribute pci_slot_attr_cur_speed =91 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);92 93static struct attribute *pci_slot_default_attrs[] = {94 &pci_slot_attr_address.attr,95 &pci_slot_attr_max_speed.attr,96 &pci_slot_attr_cur_speed.attr,97 NULL,98};99ATTRIBUTE_GROUPS(pci_slot_default);100 101static const struct kobj_type pci_slot_ktype = {102 .sysfs_ops = &pci_slot_sysfs_ops,103 .release = &pci_slot_release,104 .default_groups = pci_slot_default_groups,105};106 107static char *make_slot_name(const char *name)108{109 char *new_name;110 int len, max, dup;111 112 new_name = kstrdup(name, GFP_KERNEL);113 if (!new_name)114 return NULL;115 116 /*117 * Make sure we hit the realloc case the first time through the118 * loop. 'len' will be strlen(name) + 3 at that point which is119 * enough space for "name-X" and the trailing NUL.120 */121 len = strlen(name) + 2;122 max = 1;123 dup = 1;124 125 for (;;) {126 struct kobject *dup_slot;127 dup_slot = kset_find_obj(pci_slots_kset, new_name);128 if (!dup_slot)129 break;130 kobject_put(dup_slot);131 if (dup == max) {132 len++;133 max *= 10;134 kfree(new_name);135 new_name = kmalloc(len, GFP_KERNEL);136 if (!new_name)137 break;138 }139 sprintf(new_name, "%s-%d", name, dup++);140 }141 142 return new_name;143}144 145static int rename_slot(struct pci_slot *slot, const char *name)146{147 int result = 0;148 char *slot_name;149 150 if (strcmp(pci_slot_name(slot), name) == 0)151 return result;152 153 slot_name = make_slot_name(name);154 if (!slot_name)155 return -ENOMEM;156 157 result = kobject_rename(&slot->kobj, slot_name);158 kfree(slot_name);159 160 return result;161}162 163void pci_dev_assign_slot(struct pci_dev *dev)164{165 struct pci_slot *slot;166 167 mutex_lock(&pci_slot_mutex);168 list_for_each_entry(slot, &dev->bus->slots, list)169 if (PCI_SLOT(dev->devfn) == slot->number)170 dev->slot = slot;171 mutex_unlock(&pci_slot_mutex);172}173 174static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)175{176 struct pci_slot *slot;177 178 /* We already hold pci_slot_mutex */179 list_for_each_entry(slot, &parent->slots, list)180 if (slot->number == slot_nr) {181 kobject_get(&slot->kobj);182 return slot;183 }184 185 return NULL;186}187 188/**189 * pci_create_slot - create or increment refcount for physical PCI slot190 * @parent: struct pci_bus of parent bridge191 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder192 * @name: user visible string presented in /sys/bus/pci/slots/<name>193 * @hotplug: set if caller is hotplug driver, NULL otherwise194 *195 * PCI slots have first class attributes such as address, speed, width,196 * and a &struct pci_slot is used to manage them. This interface will197 * either return a new &struct pci_slot to the caller, or if the pci_slot198 * already exists, its refcount will be incremented.199 *200 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.201 *202 * There are known platforms with broken firmware that assign the same203 * name to multiple slots. Workaround these broken platforms by renaming204 * the slots on behalf of the caller. If firmware assigns name N to205 * multiple slots:206 *207 * The first slot is assigned N208 * The second slot is assigned N-1209 * The third slot is assigned N-2210 * etc.211 *212 * Placeholder slots:213 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify214 * a slot. There is one notable exception - pSeries (rpaphp), where the215 * @slot_nr cannot be determined until a device is actually inserted into216 * the slot. In this scenario, the caller may pass -1 for @slot_nr.217 *218 * The following semantics are imposed when the caller passes @slot_nr ==219 * -1. First, we no longer check for an existing %struct pci_slot, as there220 * may be many slots with @slot_nr of -1. The other change in semantics is221 * user-visible, which is the 'address' parameter presented in sysfs will222 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the223 * %struct pci_bus and bb is the bus number. In other words, the devfn of224 * the 'placeholder' slot will not be displayed.225 */226struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,227 const char *name,228 struct hotplug_slot *hotplug)229{230 struct pci_dev *dev;231 struct pci_slot *slot;232 int err = 0;233 char *slot_name = NULL;234 235 mutex_lock(&pci_slot_mutex);236 237 if (slot_nr == -1)238 goto placeholder;239 240 /*241 * Hotplug drivers are allowed to rename an existing slot,242 * but only if not already claimed.243 */244 slot = get_slot(parent, slot_nr);245 if (slot) {246 if (hotplug) {247 if ((err = slot->hotplug ? -EBUSY : 0)248 || (err = rename_slot(slot, name))) {249 kobject_put(&slot->kobj);250 slot = NULL;251 goto err;252 }253 }254 goto out;255 }256 257placeholder:258 slot = kzalloc(sizeof(*slot), GFP_KERNEL);259 if (!slot) {260 err = -ENOMEM;261 goto err;262 }263 264 slot->bus = parent;265 slot->number = slot_nr;266 267 slot->kobj.kset = pci_slots_kset;268 269 slot_name = make_slot_name(name);270 if (!slot_name) {271 err = -ENOMEM;272 kfree(slot);273 goto err;274 }275 276 INIT_LIST_HEAD(&slot->list);277 list_add(&slot->list, &parent->slots);278 279 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,280 "%s", slot_name);281 if (err) {282 kobject_put(&slot->kobj);283 goto err;284 }285 286 down_read(&pci_bus_sem);287 list_for_each_entry(dev, &parent->devices, bus_list)288 if (PCI_SLOT(dev->devfn) == slot_nr)289 dev->slot = slot;290 up_read(&pci_bus_sem);291 292 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",293 slot_nr, pci_slot_name(slot));294 295out:296 kfree(slot_name);297 mutex_unlock(&pci_slot_mutex);298 return slot;299err:300 slot = ERR_PTR(err);301 goto out;302}303EXPORT_SYMBOL_GPL(pci_create_slot);304 305/**306 * pci_destroy_slot - decrement refcount for physical PCI slot307 * @slot: struct pci_slot to decrement308 *309 * %struct pci_slot is refcounted, so destroying them is really easy; we310 * just call kobject_put on its kobj and let our release methods do the311 * rest.312 */313void pci_destroy_slot(struct pci_slot *slot)314{315 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",316 slot->number, kref_read(&slot->kobj.kref) - 1);317 318 mutex_lock(&pci_slot_mutex);319 kobject_put(&slot->kobj);320 mutex_unlock(&pci_slot_mutex);321}322EXPORT_SYMBOL_GPL(pci_destroy_slot);323 324#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)325#include <linux/pci_hotplug.h>326/**327 * pci_hp_create_module_link - create symbolic link to hotplug driver module328 * @pci_slot: struct pci_slot329 *330 * Helper function for pci_hotplug_core.c to create symbolic link to331 * the hotplug driver module.332 */333void pci_hp_create_module_link(struct pci_slot *pci_slot)334{335 struct hotplug_slot *slot = pci_slot->hotplug;336 struct kobject *kobj = NULL;337 int ret;338 339 if (!slot || !slot->ops)340 return;341 kobj = kset_find_obj(module_kset, slot->mod_name);342 if (!kobj)343 return;344 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");345 if (ret)346 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",347 ret);348 kobject_put(kobj);349}350EXPORT_SYMBOL_GPL(pci_hp_create_module_link);351 352/**353 * pci_hp_remove_module_link - remove symbolic link to the hotplug driver354 * module.355 * @pci_slot: struct pci_slot356 *357 * Helper function for pci_hotplug_core.c to remove symbolic link to358 * the hotplug driver module.359 */360void pci_hp_remove_module_link(struct pci_slot *pci_slot)361{362 sysfs_remove_link(&pci_slot->kobj, "module");363}364EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);365#endif366 367static int pci_slot_init(void)368{369 struct kset *pci_bus_kset;370 371 pci_bus_kset = bus_get_kset(&pci_bus_type);372 pci_slots_kset = kset_create_and_add("slots", NULL,373 &pci_bus_kset->kobj);374 if (!pci_slots_kset) {375 pr_err("PCI: Slot initialization failure\n");376 return -ENOMEM;377 }378 return 0;379}380 381subsys_initcall(pci_slot_init);382