Line data Source code
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 :
15 : struct kset *pci_slots_kset;
16 : EXPORT_SYMBOL_GPL(pci_slots_kset);
17 :
18 0 : static ssize_t pci_slot_attr_show(struct kobject *kobj,
19 : struct attribute *attr, char *buf)
20 : {
21 0 : struct pci_slot *slot = to_pci_slot(kobj);
22 0 : struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
23 0 : return attribute->show ? attribute->show(slot, buf) : -EIO;
24 : }
25 :
26 0 : static ssize_t pci_slot_attr_store(struct kobject *kobj,
27 : struct attribute *attr, const char *buf, size_t len)
28 : {
29 0 : struct pci_slot *slot = to_pci_slot(kobj);
30 0 : struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
31 0 : return attribute->store ? attribute->store(slot, buf, len) : -EIO;
32 : }
33 :
34 : static const struct sysfs_ops pci_slot_sysfs_ops = {
35 : .show = pci_slot_attr_show,
36 : .store = pci_slot_attr_store,
37 : };
38 :
39 0 : static ssize_t address_read_file(struct pci_slot *slot, char *buf)
40 : {
41 0 : if (slot->number == 0xff)
42 0 : return sysfs_emit(buf, "%04x:%02x\n",
43 : pci_domain_nr(slot->bus),
44 0 : slot->bus->number);
45 :
46 0 : return sysfs_emit(buf, "%04x:%02x:%02x\n",
47 : pci_domain_nr(slot->bus),
48 0 : slot->bus->number,
49 : slot->number);
50 : }
51 :
52 : static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
53 : {
54 0 : return sysfs_emit(buf, "%s\n", pci_speed_string(speed));
55 : }
56 :
57 0 : static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
58 : {
59 0 : return bus_speed_read(slot->bus->max_bus_speed, buf);
60 : }
61 :
62 0 : static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
63 : {
64 0 : return bus_speed_read(slot->bus->cur_bus_speed, buf);
65 : }
66 :
67 0 : static void pci_slot_release(struct kobject *kobj)
68 : {
69 : struct pci_dev *dev;
70 0 : 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 0 : down_read(&pci_bus_sem);
76 0 : list_for_each_entry(dev, &slot->bus->devices, bus_list)
77 0 : if (PCI_SLOT(dev->devfn) == slot->number)
78 0 : dev->slot = NULL;
79 0 : up_read(&pci_bus_sem);
80 :
81 0 : list_del(&slot->list);
82 :
83 0 : kfree(slot);
84 0 : }
85 :
86 : static struct pci_slot_attribute pci_slot_attr_address =
87 : __ATTR(address, S_IRUGO, address_read_file, NULL);
88 : static struct pci_slot_attribute pci_slot_attr_max_speed =
89 : __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
90 : static struct pci_slot_attribute pci_slot_attr_cur_speed =
91 : __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
92 :
93 : static 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 : };
99 : ATTRIBUTE_GROUPS(pci_slot_default);
100 :
101 : static 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 :
107 0 : static char *make_slot_name(const char *name)
108 : {
109 : char *new_name;
110 : int len, max, dup;
111 :
112 0 : new_name = kstrdup(name, GFP_KERNEL);
113 0 : if (!new_name)
114 : return NULL;
115 :
116 : /*
117 : * Make sure we hit the realloc case the first time through the
118 : * loop. 'len' will be strlen(name) + 3 at that point which is
119 : * enough space for "name-X" and the trailing NUL.
120 : */
121 0 : len = strlen(name) + 2;
122 0 : max = 1;
123 0 : dup = 1;
124 :
125 0 : for (;;) {
126 : struct kobject *dup_slot;
127 0 : dup_slot = kset_find_obj(pci_slots_kset, new_name);
128 0 : if (!dup_slot)
129 : break;
130 0 : kobject_put(dup_slot);
131 0 : if (dup == max) {
132 0 : len++;
133 0 : max *= 10;
134 0 : kfree(new_name);
135 0 : new_name = kmalloc(len, GFP_KERNEL);
136 0 : if (!new_name)
137 : break;
138 : }
139 0 : sprintf(new_name, "%s-%d", name, dup++);
140 : }
141 :
142 : return new_name;
143 : }
144 :
145 0 : static int rename_slot(struct pci_slot *slot, const char *name)
146 : {
147 0 : int result = 0;
148 : char *slot_name;
149 :
150 0 : if (strcmp(pci_slot_name(slot), name) == 0)
151 : return result;
152 :
153 0 : slot_name = make_slot_name(name);
154 0 : if (!slot_name)
155 : return -ENOMEM;
156 :
157 0 : result = kobject_rename(&slot->kobj, slot_name);
158 0 : kfree(slot_name);
159 :
160 0 : return result;
161 : }
162 :
163 0 : void pci_dev_assign_slot(struct pci_dev *dev)
164 : {
165 : struct pci_slot *slot;
166 :
167 0 : mutex_lock(&pci_slot_mutex);
168 0 : list_for_each_entry(slot, &dev->bus->slots, list)
169 0 : if (PCI_SLOT(dev->devfn) == slot->number)
170 0 : dev->slot = slot;
171 0 : mutex_unlock(&pci_slot_mutex);
172 0 : }
173 :
174 : static 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 0 : list_for_each_entry(slot, &parent->slots, list)
180 0 : if (slot->number == slot_nr) {
181 0 : 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 slot
190 : * @parent: struct pci_bus of parent bridge
191 : * @slot_nr: PCI_SLOT(pci_dev->devfn) or -1 for placeholder
192 : * @name: user visible string presented in /sys/bus/pci/slots/<name>
193 : * @hotplug: set if caller is hotplug driver, NULL otherwise
194 : *
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 will
197 : * either return a new &struct pci_slot to the caller, or if the pci_slot
198 : * 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 same
203 : * name to multiple slots. Workaround these broken platforms by renaming
204 : * the slots on behalf of the caller. If firmware assigns name N to
205 : * multiple slots:
206 : *
207 : * The first slot is assigned N
208 : * The second slot is assigned N-1
209 : * The third slot is assigned N-2
210 : * etc.
211 : *
212 : * Placeholder slots:
213 : * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
214 : * a slot. There is one notable exception - pSeries (rpaphp), where the
215 : * @slot_nr cannot be determined until a device is actually inserted into
216 : * 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 there
220 : * may be many slots with @slot_nr of -1. The other change in semantics is
221 : * user-visible, which is the 'address' parameter presented in sysfs will
222 : * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
223 : * %struct pci_bus and bb is the bus number. In other words, the devfn of
224 : * the 'placeholder' slot will not be displayed.
225 : */
226 0 : struct 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 0 : int err = 0;
233 0 : char *slot_name = NULL;
234 :
235 0 : mutex_lock(&pci_slot_mutex);
236 :
237 0 : 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 0 : slot = get_slot(parent, slot_nr);
245 0 : if (slot) {
246 0 : if (hotplug) {
247 0 : if ((err = slot->hotplug ? -EBUSY : 0)
248 0 : || (err = rename_slot(slot, name))) {
249 0 : kobject_put(&slot->kobj);
250 0 : slot = NULL;
251 0 : goto err;
252 : }
253 : }
254 : goto out;
255 : }
256 :
257 : placeholder:
258 0 : slot = kzalloc(sizeof(*slot), GFP_KERNEL);
259 0 : if (!slot) {
260 : err = -ENOMEM;
261 : goto err;
262 : }
263 :
264 0 : slot->bus = parent;
265 0 : slot->number = slot_nr;
266 :
267 0 : slot->kobj.kset = pci_slots_kset;
268 :
269 0 : slot_name = make_slot_name(name);
270 0 : if (!slot_name) {
271 0 : err = -ENOMEM;
272 0 : kfree(slot);
273 0 : goto err;
274 : }
275 :
276 0 : INIT_LIST_HEAD(&slot->list);
277 0 : list_add(&slot->list, &parent->slots);
278 :
279 0 : err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
280 : "%s", slot_name);
281 0 : if (err) {
282 0 : kobject_put(&slot->kobj);
283 0 : goto err;
284 : }
285 :
286 0 : down_read(&pci_bus_sem);
287 0 : list_for_each_entry(dev, &parent->devices, bus_list)
288 0 : if (PCI_SLOT(dev->devfn) == slot_nr)
289 0 : dev->slot = slot;
290 0 : 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 :
295 : out:
296 0 : kfree(slot_name);
297 0 : mutex_unlock(&pci_slot_mutex);
298 0 : return slot;
299 : err:
300 0 : slot = ERR_PTR(err);
301 0 : goto out;
302 : }
303 : EXPORT_SYMBOL_GPL(pci_create_slot);
304 :
305 : /**
306 : * pci_destroy_slot - decrement refcount for physical PCI slot
307 : * @slot: struct pci_slot to decrement
308 : *
309 : * %struct pci_slot is refcounted, so destroying them is really easy; we
310 : * just call kobject_put on its kobj and let our release methods do the
311 : * rest.
312 : */
313 0 : void 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 0 : mutex_lock(&pci_slot_mutex);
319 0 : kobject_put(&slot->kobj);
320 0 : mutex_unlock(&pci_slot_mutex);
321 0 : }
322 : EXPORT_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 module
328 : * @pci_slot: struct pci_slot
329 : *
330 : * Helper function for pci_hotplug_core.c to create symbolic link to
331 : * the hotplug driver module.
332 : */
333 : void 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 : }
350 : EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
351 :
352 : /**
353 : * pci_hp_remove_module_link - remove symbolic link to the hotplug driver
354 : * module.
355 : * @pci_slot: struct pci_slot
356 : *
357 : * Helper function for pci_hotplug_core.c to remove symbolic link to
358 : * the hotplug driver module.
359 : */
360 : void pci_hp_remove_module_link(struct pci_slot *pci_slot)
361 : {
362 : sysfs_remove_link(&pci_slot->kobj, "module");
363 : }
364 : EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
365 : #endif
366 :
367 1 : static int pci_slot_init(void)
368 : {
369 : struct kset *pci_bus_kset;
370 :
371 1 : pci_bus_kset = bus_get_kset(&pci_bus_type);
372 1 : pci_slots_kset = kset_create_and_add("slots", NULL,
373 : &pci_bus_kset->kobj);
374 1 : if (!pci_slots_kset) {
375 0 : pr_err("PCI: Slot initialization failure\n");
376 0 : return -ENOMEM;
377 : }
378 : return 0;
379 : }
380 :
381 : subsys_initcall(pci_slot_init);
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