1 // SPDX-License-Identifier: GPL-2.0
4 * Copyright (C) 2006 Matthew Wilcox <matthew@wil.cx>
5 * Copyright (C) 2006-2009 Hewlett-Packard Development Company, L.P.
6 * Alex Chiang <achiang@hp.com>
9 #include <linux/kobject.h>
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <linux/pci.h>
13 #include <linux/err.h>
16 struct kset *pci_slots_kset;
17 EXPORT_SYMBOL_GPL(pci_slots_kset);
18 static DEFINE_MUTEX(pci_slot_mutex);
20 static ssize_t pci_slot_attr_show(struct kobject *kobj,
21 struct attribute *attr, char *buf)
23 struct pci_slot *slot = to_pci_slot(kobj);
24 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
25 return attribute->show ? attribute->show(slot, buf) : -EIO;
28 static ssize_t pci_slot_attr_store(struct kobject *kobj,
29 struct attribute *attr, const char *buf, size_t len)
31 struct pci_slot *slot = to_pci_slot(kobj);
32 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
33 return attribute->store ? attribute->store(slot, buf, len) : -EIO;
36 static const struct sysfs_ops pci_slot_sysfs_ops = {
37 .show = pci_slot_attr_show,
38 .store = pci_slot_attr_store,
41 static ssize_t address_read_file(struct pci_slot *slot, char *buf)
43 if (slot->number == 0xff)
44 return sprintf(buf, "%04x:%02x\n",
45 pci_domain_nr(slot->bus),
48 return sprintf(buf, "%04x:%02x:%02x\n",
49 pci_domain_nr(slot->bus),
54 /* these strings match up with the values in pci_bus_speed */
55 static const char *pci_bus_speed_strings[] = {
56 "33 MHz PCI", /* 0x00 */
57 "66 MHz PCI", /* 0x01 */
58 "66 MHz PCI-X", /* 0x02 */
59 "100 MHz PCI-X", /* 0x03 */
60 "133 MHz PCI-X", /* 0x04 */
65 "66 MHz PCI-X 266", /* 0x09 */
66 "100 MHz PCI-X 266", /* 0x0a */
67 "133 MHz PCI-X 266", /* 0x0b */
68 "Unknown AGP", /* 0x0c */
73 "66 MHz PCI-X 533", /* 0x11 */
74 "100 MHz PCI-X 533", /* 0x12 */
75 "133 MHz PCI-X 533", /* 0x13 */
76 "2.5 GT/s PCIe", /* 0x14 */
77 "5.0 GT/s PCIe", /* 0x15 */
78 "8.0 GT/s PCIe", /* 0x16 */
79 "16.0 GT/s PCIe", /* 0x17 */
82 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
84 const char *speed_string;
86 if (speed < ARRAY_SIZE(pci_bus_speed_strings))
87 speed_string = pci_bus_speed_strings[speed];
89 speed_string = "Unknown";
91 return sprintf(buf, "%s\n", speed_string);
94 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
96 return bus_speed_read(slot->bus->max_bus_speed, buf);
99 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
101 return bus_speed_read(slot->bus->cur_bus_speed, buf);
104 static void pci_slot_release(struct kobject *kobj)
107 struct pci_slot *slot = to_pci_slot(kobj);
109 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
110 slot->number, pci_slot_name(slot));
112 down_read(&pci_bus_sem);
113 list_for_each_entry(dev, &slot->bus->devices, bus_list)
114 if (PCI_SLOT(dev->devfn) == slot->number)
116 up_read(&pci_bus_sem);
118 list_del(&slot->list);
123 static struct pci_slot_attribute pci_slot_attr_address =
124 __ATTR(address, S_IRUGO, address_read_file, NULL);
125 static struct pci_slot_attribute pci_slot_attr_max_speed =
126 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
127 static struct pci_slot_attribute pci_slot_attr_cur_speed =
128 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
130 static struct attribute *pci_slot_default_attrs[] = {
131 &pci_slot_attr_address.attr,
132 &pci_slot_attr_max_speed.attr,
133 &pci_slot_attr_cur_speed.attr,
137 static struct kobj_type pci_slot_ktype = {
138 .sysfs_ops = &pci_slot_sysfs_ops,
139 .release = &pci_slot_release,
140 .default_attrs = pci_slot_default_attrs,
143 static char *make_slot_name(const char *name)
148 new_name = kstrdup(name, GFP_KERNEL);
153 * Make sure we hit the realloc case the first time through the
154 * loop. 'len' will be strlen(name) + 3 at that point which is
155 * enough space for "name-X" and the trailing NUL.
157 len = strlen(name) + 2;
162 struct kobject *dup_slot;
163 dup_slot = kset_find_obj(pci_slots_kset, new_name);
166 kobject_put(dup_slot);
171 new_name = kmalloc(len, GFP_KERNEL);
175 sprintf(new_name, "%s-%d", name, dup++);
181 static int rename_slot(struct pci_slot *slot, const char *name)
186 if (strcmp(pci_slot_name(slot), name) == 0)
189 slot_name = make_slot_name(name);
193 result = kobject_rename(&slot->kobj, slot_name);
199 void pci_dev_assign_slot(struct pci_dev *dev)
201 struct pci_slot *slot;
203 mutex_lock(&pci_slot_mutex);
204 list_for_each_entry(slot, &dev->bus->slots, list)
205 if (PCI_SLOT(dev->devfn) == slot->number)
207 mutex_unlock(&pci_slot_mutex);
210 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
212 struct pci_slot *slot;
214 /* We already hold pci_slot_mutex */
215 list_for_each_entry(slot, &parent->slots, list)
216 if (slot->number == slot_nr) {
217 kobject_get(&slot->kobj);
225 * pci_create_slot - create or increment refcount for physical PCI slot
226 * @parent: struct pci_bus of parent bridge
227 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
228 * @name: user visible string presented in /sys/bus/pci/slots/<name>
229 * @hotplug: set if caller is hotplug driver, NULL otherwise
231 * PCI slots have first class attributes such as address, speed, width,
232 * and a &struct pci_slot is used to manage them. This interface will
233 * either return a new &struct pci_slot to the caller, or if the pci_slot
234 * already exists, its refcount will be incremented.
236 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
238 * There are known platforms with broken firmware that assign the same
239 * name to multiple slots. Workaround these broken platforms by renaming
240 * the slots on behalf of the caller. If firmware assigns name N to
243 * The first slot is assigned N
244 * The second slot is assigned N-1
245 * The third slot is assigned N-2
249 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
250 * a slot. There is one notable exception - pSeries (rpaphp), where the
251 * @slot_nr cannot be determined until a device is actually inserted into
252 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
254 * The following semantics are imposed when the caller passes @slot_nr ==
255 * -1. First, we no longer check for an existing %struct pci_slot, as there
256 * may be many slots with @slot_nr of -1. The other change in semantics is
257 * user-visible, which is the 'address' parameter presented in sysfs will
258 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
259 * %struct pci_bus and bb is the bus number. In other words, the devfn of
260 * the 'placeholder' slot will not be displayed.
262 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
264 struct hotplug_slot *hotplug)
267 struct pci_slot *slot;
269 char *slot_name = NULL;
271 mutex_lock(&pci_slot_mutex);
277 * Hotplug drivers are allowed to rename an existing slot,
278 * but only if not already claimed.
280 slot = get_slot(parent, slot_nr);
283 if ((err = slot->hotplug ? -EBUSY : 0)
284 || (err = rename_slot(slot, name))) {
285 kobject_put(&slot->kobj);
294 slot = kzalloc(sizeof(*slot), GFP_KERNEL);
301 slot->number = slot_nr;
303 slot->kobj.kset = pci_slots_kset;
305 slot_name = make_slot_name(name);
311 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
316 INIT_LIST_HEAD(&slot->list);
317 list_add(&slot->list, &parent->slots);
319 down_read(&pci_bus_sem);
320 list_for_each_entry(dev, &parent->devices, bus_list)
321 if (PCI_SLOT(dev->devfn) == slot_nr)
323 up_read(&pci_bus_sem);
325 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
326 slot_nr, pci_slot_name(slot));
330 mutex_unlock(&pci_slot_mutex);
337 EXPORT_SYMBOL_GPL(pci_create_slot);
340 * pci_destroy_slot - decrement refcount for physical PCI slot
341 * @slot: struct pci_slot to decrement
343 * %struct pci_slot is refcounted, so destroying them is really easy; we
344 * just call kobject_put on its kobj and let our release methods do the
347 void pci_destroy_slot(struct pci_slot *slot)
349 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
350 slot->number, kref_read(&slot->kobj.kref) - 1);
352 mutex_lock(&pci_slot_mutex);
353 kobject_put(&slot->kobj);
354 mutex_unlock(&pci_slot_mutex);
356 EXPORT_SYMBOL_GPL(pci_destroy_slot);
358 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
359 #include <linux/pci_hotplug.h>
361 * pci_hp_create_link - create symbolic link to the hotplug driver module.
362 * @pci_slot: struct pci_slot
364 * Helper function for pci_hotplug_core.c to create symbolic link to
365 * the hotplug driver module.
367 void pci_hp_create_module_link(struct pci_slot *pci_slot)
369 struct hotplug_slot *slot = pci_slot->hotplug;
370 struct kobject *kobj = NULL;
373 if (!slot || !slot->ops)
375 kobj = kset_find_obj(module_kset, slot->ops->mod_name);
378 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
380 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
384 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
387 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
388 * @pci_slot: struct pci_slot
390 * Helper function for pci_hotplug_core.c to remove symbolic link to
391 * the hotplug driver module.
393 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
395 sysfs_remove_link(&pci_slot->kobj, "module");
397 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
400 static int pci_slot_init(void)
402 struct kset *pci_bus_kset;
404 pci_bus_kset = bus_get_kset(&pci_bus_type);
405 pci_slots_kset = kset_create_and_add("slots", NULL,
406 &pci_bus_kset->kobj);
407 if (!pci_slots_kset) {
408 printk(KERN_ERR "PCI: Slot initialization failure\n");
414 subsys_initcall(pci_slot_init);