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