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v5.4
  1// SPDX-License-Identifier: GPL-2.0
  2/*
 
  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 sprintf(buf, "%04x:%02x\n",
 43				pci_domain_nr(slot->bus),
 44				slot->bus->number);
 45	else
 46		return sprintf(buf, "%04x:%02x:%02x\n",
 47				pci_domain_nr(slot->bus),
 48				slot->bus->number,
 49				slot->number);
 50}
 51
 52/* these strings match up with the values in pci_bus_speed */
 53static const char *pci_bus_speed_strings[] = {
 54	"33 MHz PCI",		/* 0x00 */
 55	"66 MHz PCI",		/* 0x01 */
 56	"66 MHz PCI-X",		/* 0x02 */
 57	"100 MHz PCI-X",	/* 0x03 */
 58	"133 MHz PCI-X",	/* 0x04 */
 59	NULL,			/* 0x05 */
 60	NULL,			/* 0x06 */
 61	NULL,			/* 0x07 */
 62	NULL,			/* 0x08 */
 63	"66 MHz PCI-X 266",	/* 0x09 */
 64	"100 MHz PCI-X 266",	/* 0x0a */
 65	"133 MHz PCI-X 266",	/* 0x0b */
 66	"Unknown AGP",		/* 0x0c */
 67	"1x AGP",		/* 0x0d */
 68	"2x AGP",		/* 0x0e */
 69	"4x AGP",		/* 0x0f */
 70	"8x AGP",		/* 0x10 */
 71	"66 MHz PCI-X 533",	/* 0x11 */
 72	"100 MHz PCI-X 533",	/* 0x12 */
 73	"133 MHz PCI-X 533",	/* 0x13 */
 74	"2.5 GT/s PCIe",	/* 0x14 */
 75	"5.0 GT/s PCIe",	/* 0x15 */
 76	"8.0 GT/s PCIe",	/* 0x16 */
 77	"16.0 GT/s PCIe",	/* 0x17 */
 78	"32.0 GT/s PCIe",	/* 0x18 */
 79};
 80
 81static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
 82{
 83	const char *speed_string;
 84
 85	if (speed < ARRAY_SIZE(pci_bus_speed_strings))
 86		speed_string = pci_bus_speed_strings[speed];
 87	else
 88		speed_string = "Unknown";
 89
 90	return sprintf(buf, "%s\n", speed_string);
 91}
 92
 93static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
 94{
 95	return bus_speed_read(slot->bus->max_bus_speed, buf);
 96}
 97
 98static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
 99{
100	return bus_speed_read(slot->bus->cur_bus_speed, buf);
101}
102
103static void pci_slot_release(struct kobject *kobj)
104{
105	struct pci_dev *dev;
106	struct pci_slot *slot = to_pci_slot(kobj);
107
108	dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
109		slot->number, pci_slot_name(slot));
110
111	down_read(&pci_bus_sem);
112	list_for_each_entry(dev, &slot->bus->devices, bus_list)
113		if (PCI_SLOT(dev->devfn) == slot->number)
114			dev->slot = NULL;
115	up_read(&pci_bus_sem);
116
117	list_del(&slot->list);
118
119	kfree(slot);
120}
121
122static struct pci_slot_attribute pci_slot_attr_address =
123	__ATTR(address, S_IRUGO, address_read_file, NULL);
124static struct pci_slot_attribute pci_slot_attr_max_speed =
125	__ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
126static struct pci_slot_attribute pci_slot_attr_cur_speed =
127	__ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
128
129static struct attribute *pci_slot_default_attrs[] = {
130	&pci_slot_attr_address.attr,
131	&pci_slot_attr_max_speed.attr,
132	&pci_slot_attr_cur_speed.attr,
133	NULL,
134};
135
136static struct kobj_type pci_slot_ktype = {
137	.sysfs_ops = &pci_slot_sysfs_ops,
138	.release = &pci_slot_release,
139	.default_attrs = pci_slot_default_attrs,
140};
141
142static char *make_slot_name(const char *name)
143{
144	char *new_name;
145	int len, max, dup;
146
147	new_name = kstrdup(name, GFP_KERNEL);
148	if (!new_name)
149		return NULL;
150
151	/*
152	 * Make sure we hit the realloc case the first time through the
153	 * loop.  'len' will be strlen(name) + 3 at that point which is
154	 * enough space for "name-X" and the trailing NUL.
155	 */
156	len = strlen(name) + 2;
157	max = 1;
158	dup = 1;
159
160	for (;;) {
161		struct kobject *dup_slot;
162		dup_slot = kset_find_obj(pci_slots_kset, new_name);
163		if (!dup_slot)
164			break;
165		kobject_put(dup_slot);
166		if (dup == max) {
167			len++;
168			max *= 10;
169			kfree(new_name);
170			new_name = kmalloc(len, GFP_KERNEL);
171			if (!new_name)
172				break;
173		}
174		sprintf(new_name, "%s-%d", name, dup++);
175	}
176
177	return new_name;
178}
179
180static int rename_slot(struct pci_slot *slot, const char *name)
181{
182	int result = 0;
183	char *slot_name;
184
185	if (strcmp(pci_slot_name(slot), name) == 0)
186		return result;
187
188	slot_name = make_slot_name(name);
189	if (!slot_name)
190		return -ENOMEM;
191
192	result = kobject_rename(&slot->kobj, slot_name);
193	kfree(slot_name);
194
195	return result;
196}
197
198void pci_dev_assign_slot(struct pci_dev *dev)
199{
200	struct pci_slot *slot;
201
202	mutex_lock(&pci_slot_mutex);
203	list_for_each_entry(slot, &dev->bus->slots, list)
204		if (PCI_SLOT(dev->devfn) == slot->number)
205			dev->slot = slot;
206	mutex_unlock(&pci_slot_mutex);
207}
208
209static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
210{
211	struct pci_slot *slot;
212
213	/* We already hold pci_slot_mutex */
214	list_for_each_entry(slot, &parent->slots, list)
215		if (slot->number == slot_nr) {
216			kobject_get(&slot->kobj);
217			return slot;
218		}
219
220	return NULL;
221}
222
223/**
224 * pci_create_slot - create or increment refcount for physical PCI slot
225 * @parent: struct pci_bus of parent bridge
226 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
227 * @name: user visible string presented in /sys/bus/pci/slots/<name>
228 * @hotplug: set if caller is hotplug driver, NULL otherwise
229 *
230 * PCI slots have first class attributes such as address, speed, width,
231 * and a &struct pci_slot is used to manage them. This interface will
232 * either return a new &struct pci_slot to the caller, or if the pci_slot
233 * already exists, its refcount will be incremented.
234 *
235 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
236 *
237 * There are known platforms with broken firmware that assign the same
238 * name to multiple slots. Workaround these broken platforms by renaming
239 * the slots on behalf of the caller. If firmware assigns name N to
240 * multiple slots:
241 *
242 * The first slot is assigned N
243 * The second slot is assigned N-1
244 * The third slot is assigned N-2
245 * etc.
246 *
247 * Placeholder slots:
248 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
249 * a slot. There is one notable exception - pSeries (rpaphp), where the
250 * @slot_nr cannot be determined until a device is actually inserted into
251 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
252 *
253 * The following semantics are imposed when the caller passes @slot_nr ==
254 * -1. First, we no longer check for an existing %struct pci_slot, as there
255 * may be many slots with @slot_nr of -1.  The other change in semantics is
256 * user-visible, which is the 'address' parameter presented in sysfs will
257 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
258 * %struct pci_bus and bb is the bus number. In other words, the devfn of
259 * the 'placeholder' slot will not be displayed.
260 */
261struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
262				 const char *name,
263				 struct hotplug_slot *hotplug)
264{
265	struct pci_dev *dev;
266	struct pci_slot *slot;
267	int err = 0;
268	char *slot_name = NULL;
269
270	mutex_lock(&pci_slot_mutex);
271
272	if (slot_nr == -1)
273		goto placeholder;
274
275	/*
276	 * Hotplug drivers are allowed to rename an existing slot,
277	 * but only if not already claimed.
278	 */
279	slot = get_slot(parent, slot_nr);
280	if (slot) {
281		if (hotplug) {
282			if ((err = slot->hotplug ? -EBUSY : 0)
283			     || (err = rename_slot(slot, name))) {
284				kobject_put(&slot->kobj);
285				slot = NULL;
286				goto err;
287			}
288		}
289		goto out;
290	}
291
292placeholder:
293	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
294	if (!slot) {
295		err = -ENOMEM;
296		goto err;
297	}
298
299	slot->bus = parent;
300	slot->number = slot_nr;
301
302	slot->kobj.kset = pci_slots_kset;
303
304	slot_name = make_slot_name(name);
305	if (!slot_name) {
306		err = -ENOMEM;
307		goto err;
308	}
309
310	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
311				   "%s", slot_name);
312	if (err)
313		goto err;
314
315	INIT_LIST_HEAD(&slot->list);
316	list_add(&slot->list, &parent->slots);
317
318	down_read(&pci_bus_sem);
319	list_for_each_entry(dev, &parent->devices, bus_list)
320		if (PCI_SLOT(dev->devfn) == slot_nr)
321			dev->slot = slot;
322	up_read(&pci_bus_sem);
323
324	dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
325		slot_nr, pci_slot_name(slot));
326
327out:
328	kfree(slot_name);
329	mutex_unlock(&pci_slot_mutex);
330	return slot;
331err:
332	kfree(slot);
333	slot = ERR_PTR(err);
334	goto out;
335}
336EXPORT_SYMBOL_GPL(pci_create_slot);
337
338/**
339 * pci_destroy_slot - decrement refcount for physical PCI slot
340 * @slot: struct pci_slot to decrement
341 *
342 * %struct pci_slot is refcounted, so destroying them is really easy; we
343 * just call kobject_put on its kobj and let our release methods do the
344 * rest.
345 */
346void pci_destroy_slot(struct pci_slot *slot)
347{
348	dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
349		slot->number, kref_read(&slot->kobj.kref) - 1);
350
351	mutex_lock(&pci_slot_mutex);
352	kobject_put(&slot->kobj);
353	mutex_unlock(&pci_slot_mutex);
354}
355EXPORT_SYMBOL_GPL(pci_destroy_slot);
356
357#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
358#include <linux/pci_hotplug.h>
359/**
360 * pci_hp_create_link - create symbolic link to the hotplug driver module.
361 * @pci_slot: struct pci_slot
362 *
363 * Helper function for pci_hotplug_core.c to create symbolic link to
364 * the hotplug driver module.
365 */
366void pci_hp_create_module_link(struct pci_slot *pci_slot)
367{
368	struct hotplug_slot *slot = pci_slot->hotplug;
369	struct kobject *kobj = NULL;
370	int ret;
371
372	if (!slot || !slot->ops)
373		return;
374	kobj = kset_find_obj(module_kset, slot->mod_name);
375	if (!kobj)
376		return;
377	ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
378	if (ret)
379		dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
380			ret);
381	kobject_put(kobj);
382}
383EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
384
385/**
386 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
387 * @pci_slot: struct pci_slot
388 *
389 * Helper function for pci_hotplug_core.c to remove symbolic link to
390 * the hotplug driver module.
391 */
392void pci_hp_remove_module_link(struct pci_slot *pci_slot)
393{
394	sysfs_remove_link(&pci_slot->kobj, "module");
395}
396EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
397#endif
398
399static int pci_slot_init(void)
400{
401	struct kset *pci_bus_kset;
402
403	pci_bus_kset = bus_get_kset(&pci_bus_type);
404	pci_slots_kset = kset_create_and_add("slots", NULL,
405						&pci_bus_kset->kobj);
406	if (!pci_slots_kset) {
407		pr_err("PCI: Slot initialization failure\n");
408		return -ENOMEM;
409	}
410	return 0;
411}
412
413subsys_initcall(pci_slot_init);
v4.10.11
 
  1/*
  2 * drivers/pci/slot.c
  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);
 17static DEFINE_MUTEX(pci_slot_mutex);
 18
 19static ssize_t pci_slot_attr_show(struct kobject *kobj,
 20					struct attribute *attr, char *buf)
 21{
 22	struct pci_slot *slot = to_pci_slot(kobj);
 23	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
 24	return attribute->show ? attribute->show(slot, buf) : -EIO;
 25}
 26
 27static ssize_t pci_slot_attr_store(struct kobject *kobj,
 28			struct attribute *attr, const char *buf, size_t len)
 29{
 30	struct pci_slot *slot = to_pci_slot(kobj);
 31	struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
 32	return attribute->store ? attribute->store(slot, buf, len) : -EIO;
 33}
 34
 35static const struct sysfs_ops pci_slot_sysfs_ops = {
 36	.show = pci_slot_attr_show,
 37	.store = pci_slot_attr_store,
 38};
 39
 40static ssize_t address_read_file(struct pci_slot *slot, char *buf)
 41{
 42	if (slot->number == 0xff)
 43		return sprintf(buf, "%04x:%02x\n",
 44				pci_domain_nr(slot->bus),
 45				slot->bus->number);
 46	else
 47		return sprintf(buf, "%04x:%02x:%02x\n",
 48				pci_domain_nr(slot->bus),
 49				slot->bus->number,
 50				slot->number);
 51}
 52
 53/* these strings match up with the values in pci_bus_speed */
 54static const char *pci_bus_speed_strings[] = {
 55	"33 MHz PCI",		/* 0x00 */
 56	"66 MHz PCI",		/* 0x01 */
 57	"66 MHz PCI-X",		/* 0x02 */
 58	"100 MHz PCI-X",	/* 0x03 */
 59	"133 MHz PCI-X",	/* 0x04 */
 60	NULL,			/* 0x05 */
 61	NULL,			/* 0x06 */
 62	NULL,			/* 0x07 */
 63	NULL,			/* 0x08 */
 64	"66 MHz PCI-X 266",	/* 0x09 */
 65	"100 MHz PCI-X 266",	/* 0x0a */
 66	"133 MHz PCI-X 266",	/* 0x0b */
 67	"Unknown AGP",		/* 0x0c */
 68	"1x AGP",		/* 0x0d */
 69	"2x AGP",		/* 0x0e */
 70	"4x AGP",		/* 0x0f */
 71	"8x AGP",		/* 0x10 */
 72	"66 MHz PCI-X 533",	/* 0x11 */
 73	"100 MHz PCI-X 533",	/* 0x12 */
 74	"133 MHz PCI-X 533",	/* 0x13 */
 75	"2.5 GT/s PCIe",	/* 0x14 */
 76	"5.0 GT/s PCIe",	/* 0x15 */
 77	"8.0 GT/s PCIe",	/* 0x16 */
 
 
 78};
 79
 80static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
 81{
 82	const char *speed_string;
 83
 84	if (speed < ARRAY_SIZE(pci_bus_speed_strings))
 85		speed_string = pci_bus_speed_strings[speed];
 86	else
 87		speed_string = "Unknown";
 88
 89	return sprintf(buf, "%s\n", speed_string);
 90}
 91
 92static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
 93{
 94	return bus_speed_read(slot->bus->max_bus_speed, buf);
 95}
 96
 97static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
 98{
 99	return bus_speed_read(slot->bus->cur_bus_speed, buf);
100}
101
102static void pci_slot_release(struct kobject *kobj)
103{
104	struct pci_dev *dev;
105	struct pci_slot *slot = to_pci_slot(kobj);
106
107	dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
108		slot->number, pci_slot_name(slot));
109
110	down_read(&pci_bus_sem);
111	list_for_each_entry(dev, &slot->bus->devices, bus_list)
112		if (PCI_SLOT(dev->devfn) == slot->number)
113			dev->slot = NULL;
114	up_read(&pci_bus_sem);
115
116	list_del(&slot->list);
117
118	kfree(slot);
119}
120
121static struct pci_slot_attribute pci_slot_attr_address =
122	__ATTR(address, S_IRUGO, address_read_file, NULL);
123static struct pci_slot_attribute pci_slot_attr_max_speed =
124	__ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
125static struct pci_slot_attribute pci_slot_attr_cur_speed =
126	__ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
127
128static struct attribute *pci_slot_default_attrs[] = {
129	&pci_slot_attr_address.attr,
130	&pci_slot_attr_max_speed.attr,
131	&pci_slot_attr_cur_speed.attr,
132	NULL,
133};
134
135static struct kobj_type pci_slot_ktype = {
136	.sysfs_ops = &pci_slot_sysfs_ops,
137	.release = &pci_slot_release,
138	.default_attrs = pci_slot_default_attrs,
139};
140
141static char *make_slot_name(const char *name)
142{
143	char *new_name;
144	int len, max, dup;
145
146	new_name = kstrdup(name, GFP_KERNEL);
147	if (!new_name)
148		return NULL;
149
150	/*
151	 * Make sure we hit the realloc case the first time through the
152	 * loop.  'len' will be strlen(name) + 3 at that point which is
153	 * enough space for "name-X" and the trailing NUL.
154	 */
155	len = strlen(name) + 2;
156	max = 1;
157	dup = 1;
158
159	for (;;) {
160		struct kobject *dup_slot;
161		dup_slot = kset_find_obj(pci_slots_kset, new_name);
162		if (!dup_slot)
163			break;
164		kobject_put(dup_slot);
165		if (dup == max) {
166			len++;
167			max *= 10;
168			kfree(new_name);
169			new_name = kmalloc(len, GFP_KERNEL);
170			if (!new_name)
171				break;
172		}
173		sprintf(new_name, "%s-%d", name, dup++);
174	}
175
176	return new_name;
177}
178
179static int rename_slot(struct pci_slot *slot, const char *name)
180{
181	int result = 0;
182	char *slot_name;
183
184	if (strcmp(pci_slot_name(slot), name) == 0)
185		return result;
186
187	slot_name = make_slot_name(name);
188	if (!slot_name)
189		return -ENOMEM;
190
191	result = kobject_rename(&slot->kobj, slot_name);
192	kfree(slot_name);
193
194	return result;
195}
196
197void pci_dev_assign_slot(struct pci_dev *dev)
198{
199	struct pci_slot *slot;
200
201	mutex_lock(&pci_slot_mutex);
202	list_for_each_entry(slot, &dev->bus->slots, list)
203		if (PCI_SLOT(dev->devfn) == slot->number)
204			dev->slot = slot;
205	mutex_unlock(&pci_slot_mutex);
206}
207
208static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
209{
210	struct pci_slot *slot;
211
212	/* We already hold pci_slot_mutex */
213	list_for_each_entry(slot, &parent->slots, list)
214		if (slot->number == slot_nr) {
215			kobject_get(&slot->kobj);
216			return slot;
217		}
218
219	return NULL;
220}
221
222/**
223 * pci_create_slot - create or increment refcount for physical PCI slot
224 * @parent: struct pci_bus of parent bridge
225 * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
226 * @name: user visible string presented in /sys/bus/pci/slots/<name>
227 * @hotplug: set if caller is hotplug driver, NULL otherwise
228 *
229 * PCI slots have first class attributes such as address, speed, width,
230 * and a &struct pci_slot is used to manage them. This interface will
231 * either return a new &struct pci_slot to the caller, or if the pci_slot
232 * already exists, its refcount will be incremented.
233 *
234 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
235 *
236 * There are known platforms with broken firmware that assign the same
237 * name to multiple slots. Workaround these broken platforms by renaming
238 * the slots on behalf of the caller. If firmware assigns name N to
239 * multiple slots:
240 *
241 * The first slot is assigned N
242 * The second slot is assigned N-1
243 * The third slot is assigned N-2
244 * etc.
245 *
246 * Placeholder slots:
247 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
248 * a slot. There is one notable exception - pSeries (rpaphp), where the
249 * @slot_nr cannot be determined until a device is actually inserted into
250 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
251 *
252 * The following semantics are imposed when the caller passes @slot_nr ==
253 * -1. First, we no longer check for an existing %struct pci_slot, as there
254 * may be many slots with @slot_nr of -1.  The other change in semantics is
255 * user-visible, which is the 'address' parameter presented in sysfs will
256 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
257 * %struct pci_bus and bb is the bus number. In other words, the devfn of
258 * the 'placeholder' slot will not be displayed.
259 */
260struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
261				 const char *name,
262				 struct hotplug_slot *hotplug)
263{
264	struct pci_dev *dev;
265	struct pci_slot *slot;
266	int err = 0;
267	char *slot_name = NULL;
268
269	mutex_lock(&pci_slot_mutex);
270
271	if (slot_nr == -1)
272		goto placeholder;
273
274	/*
275	 * Hotplug drivers are allowed to rename an existing slot,
276	 * but only if not already claimed.
277	 */
278	slot = get_slot(parent, slot_nr);
279	if (slot) {
280		if (hotplug) {
281			if ((err = slot->hotplug ? -EBUSY : 0)
282			     || (err = rename_slot(slot, name))) {
283				kobject_put(&slot->kobj);
284				slot = NULL;
285				goto err;
286			}
287		}
288		goto out;
289	}
290
291placeholder:
292	slot = kzalloc(sizeof(*slot), GFP_KERNEL);
293	if (!slot) {
294		err = -ENOMEM;
295		goto err;
296	}
297
298	slot->bus = parent;
299	slot->number = slot_nr;
300
301	slot->kobj.kset = pci_slots_kset;
302
303	slot_name = make_slot_name(name);
304	if (!slot_name) {
305		err = -ENOMEM;
306		goto err;
307	}
308
309	err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
310				   "%s", slot_name);
311	if (err)
312		goto err;
313
314	INIT_LIST_HEAD(&slot->list);
315	list_add(&slot->list, &parent->slots);
316
317	down_read(&pci_bus_sem);
318	list_for_each_entry(dev, &parent->devices, bus_list)
319		if (PCI_SLOT(dev->devfn) == slot_nr)
320			dev->slot = slot;
321	up_read(&pci_bus_sem);
322
323	dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
324		slot_nr, pci_slot_name(slot));
325
326out:
327	kfree(slot_name);
328	mutex_unlock(&pci_slot_mutex);
329	return slot;
330err:
331	kfree(slot);
332	slot = ERR_PTR(err);
333	goto out;
334}
335EXPORT_SYMBOL_GPL(pci_create_slot);
336
337/**
338 * pci_destroy_slot - decrement refcount for physical PCI slot
339 * @slot: struct pci_slot to decrement
340 *
341 * %struct pci_slot is refcounted, so destroying them is really easy; we
342 * just call kobject_put on its kobj and let our release methods do the
343 * rest.
344 */
345void pci_destroy_slot(struct pci_slot *slot)
346{
347	dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
348		slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
349
350	mutex_lock(&pci_slot_mutex);
351	kobject_put(&slot->kobj);
352	mutex_unlock(&pci_slot_mutex);
353}
354EXPORT_SYMBOL_GPL(pci_destroy_slot);
355
356#if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
357#include <linux/pci_hotplug.h>
358/**
359 * pci_hp_create_link - create symbolic link to the hotplug driver module.
360 * @pci_slot: struct pci_slot
361 *
362 * Helper function for pci_hotplug_core.c to create symbolic link to
363 * the hotplug driver module.
364 */
365void pci_hp_create_module_link(struct pci_slot *pci_slot)
366{
367	struct hotplug_slot *slot = pci_slot->hotplug;
368	struct kobject *kobj = NULL;
369	int ret;
370
371	if (!slot || !slot->ops)
372		return;
373	kobj = kset_find_obj(module_kset, slot->ops->mod_name);
374	if (!kobj)
375		return;
376	ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
377	if (ret)
378		dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
379			ret);
380	kobject_put(kobj);
381}
382EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
383
384/**
385 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
386 * @pci_slot: struct pci_slot
387 *
388 * Helper function for pci_hotplug_core.c to remove symbolic link to
389 * the hotplug driver module.
390 */
391void pci_hp_remove_module_link(struct pci_slot *pci_slot)
392{
393	sysfs_remove_link(&pci_slot->kobj, "module");
394}
395EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
396#endif
397
398static int pci_slot_init(void)
399{
400	struct kset *pci_bus_kset;
401
402	pci_bus_kset = bus_get_kset(&pci_bus_type);
403	pci_slots_kset = kset_create_and_add("slots", NULL,
404						&pci_bus_kset->kobj);
405	if (!pci_slots_kset) {
406		printk(KERN_ERR "PCI: Slot initialization failure\n");
407		return -ENOMEM;
408	}
409	return 0;
410}
411
412subsys_initcall(pci_slot_init);