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/pci.h>
11 #include <linux/err.h>
12 #include "pci.h"
13
14 struct kset *pci_slots_kset;
15 EXPORT_SYMBOL_GPL(pci_slots_kset);
16
pci_slot_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)17 static ssize_t pci_slot_attr_show(struct kobject *kobj,
18 struct attribute *attr, char *buf)
19 {
20 struct pci_slot *slot = to_pci_slot(kobj);
21 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
22 return attribute->show ? attribute->show(slot, buf) : -EIO;
23 }
24
pci_slot_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t len)25 static ssize_t pci_slot_attr_store(struct kobject *kobj,
26 struct attribute *attr, const char *buf, size_t len)
27 {
28 struct pci_slot *slot = to_pci_slot(kobj);
29 struct pci_slot_attribute *attribute = to_pci_slot_attr(attr);
30 return attribute->store ? attribute->store(slot, buf, len) : -EIO;
31 }
32
33 static const struct sysfs_ops pci_slot_sysfs_ops = {
34 .show = pci_slot_attr_show,
35 .store = pci_slot_attr_store,
36 };
37
address_read_file(struct pci_slot * slot,char * buf)38 static ssize_t address_read_file(struct pci_slot *slot, char *buf)
39 {
40 if (slot->number == 0xff)
41 return sysfs_emit(buf, "%04x:%02x\n",
42 pci_domain_nr(slot->bus),
43 slot->bus->number);
44
45 /*
46 * Preserve legacy ABI expectations that hotplug drivers that manage
47 * multiple devices per slot emit 0 for the device number.
48 */
49 if (slot->number == PCI_SLOT_ALL_DEVICES)
50 return sysfs_emit(buf, "%04x:%02x:00\n",
51 pci_domain_nr(slot->bus),
52 slot->bus->number);
53
54 return sysfs_emit(buf, "%04x:%02x:%02x\n",
55 pci_domain_nr(slot->bus),
56 slot->bus->number,
57 slot->number);
58 }
59
bus_speed_read(enum pci_bus_speed speed,char * buf)60 static ssize_t bus_speed_read(enum pci_bus_speed speed, char *buf)
61 {
62 return sysfs_emit(buf, "%s\n", pci_speed_string(speed));
63 }
64
max_speed_read_file(struct pci_slot * slot,char * buf)65 static ssize_t max_speed_read_file(struct pci_slot *slot, char *buf)
66 {
67 return bus_speed_read(slot->bus->max_bus_speed, buf);
68 }
69
cur_speed_read_file(struct pci_slot * slot,char * buf)70 static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
71 {
72 return bus_speed_read(slot->bus->cur_bus_speed, buf);
73 }
74
pci_slot_release(struct kobject * kobj)75 static void pci_slot_release(struct kobject *kobj)
76 {
77 struct pci_dev *dev;
78 struct pci_slot *slot = to_pci_slot(kobj);
79
80 dev_dbg(&slot->bus->dev, "dev %02x, released physical slot %s\n",
81 slot->number, pci_slot_name(slot));
82
83 down_read(&pci_bus_sem);
84 list_for_each_entry(dev, &slot->bus->devices, bus_list)
85 if (slot->number == PCI_SLOT_ALL_DEVICES ||
86 PCI_SLOT(dev->devfn) == slot->number)
87 dev->slot = NULL;
88 up_read(&pci_bus_sem);
89
90 list_del(&slot->list);
91 pci_bus_put(slot->bus);
92
93 kfree(slot);
94 }
95
96 static struct pci_slot_attribute pci_slot_attr_address =
97 __ATTR(address, S_IRUGO, address_read_file, NULL);
98 static struct pci_slot_attribute pci_slot_attr_max_speed =
99 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
100 static struct pci_slot_attribute pci_slot_attr_cur_speed =
101 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
102
103 static struct attribute *pci_slot_default_attrs[] = {
104 &pci_slot_attr_address.attr,
105 &pci_slot_attr_max_speed.attr,
106 &pci_slot_attr_cur_speed.attr,
107 NULL,
108 };
109
110 static const struct attribute_group pci_slot_default_group = {
111 .attrs = pci_slot_default_attrs,
112 };
113
114 static const struct attribute_group *pci_slot_default_groups[] = {
115 &pci_slot_default_group,
116 #ifdef ARCH_PCI_SLOT_GROUPS
117 ARCH_PCI_SLOT_GROUPS,
118 #endif
119 NULL,
120 };
121
122 static const struct kobj_type pci_slot_ktype = {
123 .sysfs_ops = &pci_slot_sysfs_ops,
124 .release = &pci_slot_release,
125 .default_groups = pci_slot_default_groups,
126 };
127
make_slot_name(const char * name)128 static char *make_slot_name(const char *name)
129 {
130 char *new_name;
131 int len, max, dup;
132
133 new_name = kstrdup(name, GFP_KERNEL);
134 if (!new_name)
135 return NULL;
136
137 /*
138 * Make sure we hit the realloc case the first time through the
139 * loop. 'len' will be strlen(name) + 3 at that point which is
140 * enough space for "name-X" and the trailing NUL.
141 */
142 len = strlen(name) + 2;
143 max = 1;
144 dup = 1;
145
146 for (;;) {
147 struct kobject *dup_slot;
148 dup_slot = kset_find_obj(pci_slots_kset, new_name);
149 if (!dup_slot)
150 break;
151 kobject_put(dup_slot);
152 if (dup == max) {
153 len++;
154 max *= 10;
155 kfree(new_name);
156 new_name = kmalloc(len, GFP_KERNEL);
157 if (!new_name)
158 break;
159 }
160 sprintf(new_name, "%s-%d", name, dup++);
161 }
162
163 return new_name;
164 }
165
rename_slot(struct pci_slot * slot,const char * name)166 static int rename_slot(struct pci_slot *slot, const char *name)
167 {
168 int result = 0;
169 char *slot_name;
170
171 if (strcmp(pci_slot_name(slot), name) == 0)
172 return result;
173
174 slot_name = make_slot_name(name);
175 if (!slot_name)
176 return -ENOMEM;
177
178 result = kobject_rename(&slot->kobj, slot_name);
179 kfree(slot_name);
180
181 return result;
182 }
183
pci_dev_assign_slot(struct pci_dev * dev)184 void pci_dev_assign_slot(struct pci_dev *dev)
185 {
186 struct pci_slot *slot;
187
188 mutex_lock(&pci_slot_mutex);
189 list_for_each_entry(slot, &dev->bus->slots, list)
190 if (slot->number == PCI_SLOT_ALL_DEVICES ||
191 PCI_SLOT(dev->devfn) == slot->number)
192 dev->slot = slot;
193 mutex_unlock(&pci_slot_mutex);
194 }
195
get_slot(struct pci_bus * parent,int slot_nr)196 static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
197 {
198 struct pci_slot *slot;
199
200 /* We already hold pci_slot_mutex */
201 list_for_each_entry(slot, &parent->slots, list)
202 if (slot->number == slot_nr) {
203 kobject_get(&slot->kobj);
204 return slot;
205 }
206
207 return NULL;
208 }
209
210 /**
211 * pci_create_slot - create or increment refcount for physical PCI slot
212 * @parent: struct pci_bus of parent bridge
213 * @slot_nr: PCI_SLOT(pci_dev->devfn), -1 for placeholder, or
214 * PCI_SLOT_ALL_DEVICES
215 * @name: user visible string presented in /sys/bus/pci/slots/<name>
216 * @hotplug: set if caller is hotplug driver, NULL otherwise
217 *
218 * PCI slots have first class attributes such as address, speed, width,
219 * and a &struct pci_slot is used to manage them. This interface will
220 * either return a new &struct pci_slot to the caller, or if the pci_slot
221 * already exists, its refcount will be incremented.
222 *
223 * Slots are uniquely identified by a @pci_bus, @slot_nr tuple.
224 *
225 * There are known platforms with broken firmware that assign the same
226 * name to multiple slots. Workaround these broken platforms by renaming
227 * the slots on behalf of the caller. If firmware assigns name N to
228 * multiple slots:
229 *
230 * The first slot is assigned N
231 * The second slot is assigned N-1
232 * The third slot is assigned N-2
233 * etc.
234 *
235 * Placeholder slots:
236 * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
237 * a slot. There is one notable exception - pSeries (rpaphp), where the
238 * @slot_nr cannot be determined until a device is actually inserted into
239 * the slot. In this scenario, the caller may pass -1 for @slot_nr.
240 *
241 * The following semantics are imposed when the caller passes @slot_nr ==
242 * -1. First, we no longer check for an existing %struct pci_slot, as there
243 * may be many slots with @slot_nr of -1. The other change in semantics is
244 * user-visible, which is the 'address' parameter presented in sysfs will
245 * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
246 * %struct pci_bus and bb is the bus number. In other words, the devfn of
247 * the 'placeholder' slot will not be displayed.
248 *
249 * Bus-wide slots:
250 * For PCIe hotplug, the physical slot encompasses the entire secondary
251 * bus, not just a single device number. If the device supports ARI and ARI
252 * Forwarding is enabled in the upstream bridge, a multi-function device
253 * may include functions that appear to have several different device
254 * numbers, i.e., PCI_SLOT() values. Pass @slot_nr == PCI_SLOT_ALL_DEVICES
255 * to create a slot that matches all devices on the bus. Unlike placeholder
256 * slots, bus-wide slots go through normal slot lookup and reuse existing
257 * slots if present.
258 */
pci_create_slot(struct pci_bus * parent,int slot_nr,const char * name,struct hotplug_slot * hotplug)259 struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
260 const char *name,
261 struct hotplug_slot *hotplug)
262 {
263 struct pci_dev *dev;
264 struct pci_slot *slot;
265 int err = 0;
266 char *slot_name = NULL;
267
268 mutex_lock(&pci_slot_mutex);
269
270 if (slot_nr == -1)
271 goto placeholder;
272
273 /*
274 * Hotplug drivers are allowed to rename an existing slot,
275 * but only if not already claimed.
276 */
277 slot = get_slot(parent, slot_nr);
278 if (slot) {
279 if (hotplug) {
280 if (slot->hotplug) {
281 err = -EBUSY;
282 goto put_slot;
283 }
284 err = rename_slot(slot, name);
285 if (err)
286 goto put_slot;
287 }
288 goto out;
289 }
290
291 placeholder:
292 slot = kzalloc_obj(*slot);
293 if (!slot) {
294 err = -ENOMEM;
295 goto err;
296 }
297
298 slot->bus = pci_bus_get(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 pci_bus_put(slot->bus);
307 kfree(slot);
308 goto err;
309 }
310
311 INIT_LIST_HEAD(&slot->list);
312 list_add(&slot->list, &parent->slots);
313
314 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
315 "%s", slot_name);
316 if (err)
317 goto put_slot;
318
319 down_read(&pci_bus_sem);
320 list_for_each_entry(dev, &parent->devices, bus_list)
321 if (slot_nr == PCI_SLOT_ALL_DEVICES ||
322 PCI_SLOT(dev->devfn) == slot_nr)
323 dev->slot = slot;
324 up_read(&pci_bus_sem);
325
326 dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
327 slot_nr, pci_slot_name(slot));
328
329 out:
330 kfree(slot_name);
331 mutex_unlock(&pci_slot_mutex);
332 return slot;
333
334 put_slot:
335 kobject_put(&slot->kobj);
336 err:
337 slot = ERR_PTR(err);
338 goto out;
339 }
340 EXPORT_SYMBOL_GPL(pci_create_slot);
341
342 /**
343 * pci_destroy_slot - decrement refcount for physical PCI slot
344 * @slot: struct pci_slot to decrement
345 *
346 * %struct pci_slot is refcounted, so destroying them is really easy; we
347 * just call kobject_put on its kobj and let our release methods do the
348 * rest.
349 */
pci_destroy_slot(struct pci_slot * slot)350 void pci_destroy_slot(struct pci_slot *slot)
351 {
352 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
353 slot->number, kref_read(&slot->kobj.kref) - 1);
354
355 mutex_lock(&pci_slot_mutex);
356 kobject_put(&slot->kobj);
357 mutex_unlock(&pci_slot_mutex);
358 }
359 EXPORT_SYMBOL_GPL(pci_destroy_slot);
360
pci_slot_init(void)361 static int pci_slot_init(void)
362 {
363 struct kset *pci_bus_kset;
364
365 pci_bus_kset = bus_get_kset(&pci_bus_type);
366 pci_slots_kset = kset_create_and_add("slots", NULL,
367 &pci_bus_kset->kobj);
368 if (!pci_slots_kset) {
369 pr_err("PCI: Slot initialization failure\n");
370 return -ENOMEM;
371 }
372 return 0;
373 }
374
375 subsys_initcall(pci_slot_init);
376