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
15 struct kset *pci_slots_kset;
16 EXPORT_SYMBOL_GPL(pci_slots_kset);
17 static DEFINE_MUTEX(pci_slot_mutex);
18
pci_slot_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)19 static 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
pci_slot_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t len)27 static 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
35 static const struct sysfs_ops pci_slot_sysfs_ops = {
36 .show = pci_slot_attr_show,
37 .store = pci_slot_attr_store,
38 };
39
address_read_file(struct pci_slot * slot,char * buf)40 static 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 */
54 static 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
bus_speed_read(enum pci_bus_speed speed,char * buf)80 static 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
max_speed_read_file(struct pci_slot * slot,char * buf)92 static 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
cur_speed_read_file(struct pci_slot * slot,char * buf)97 static 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
pci_slot_release(struct kobject * kobj)102 static 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
121 static struct pci_slot_attribute pci_slot_attr_address =
122 __ATTR(address, S_IRUGO, address_read_file, NULL);
123 static struct pci_slot_attribute pci_slot_attr_max_speed =
124 __ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
125 static struct pci_slot_attribute pci_slot_attr_cur_speed =
126 __ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
127
128 static 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
135 static 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
make_slot_name(const char * name)141 static 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
rename_slot(struct pci_slot * slot,const char * name)179 static 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
pci_dev_assign_slot(struct pci_dev * dev)197 void 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
get_slot(struct pci_bus * parent,int slot_nr)208 static 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 */
pci_create_slot(struct pci_bus * parent,int slot_nr,const char * name,struct hotplug_slot * hotplug)260 struct 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
291 placeholder:
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 kfree(slot);
307 goto err;
308 }
309
310 INIT_LIST_HEAD(&slot->list);
311 list_add(&slot->list, &parent->slots);
312
313 err = kobject_init_and_add(&slot->kobj, &pci_slot_ktype, NULL,
314 "%s", slot_name);
315 if (err) {
316 kobject_put(&slot->kobj);
317 goto err;
318 }
319
320 down_read(&pci_bus_sem);
321 list_for_each_entry(dev, &parent->devices, bus_list)
322 if (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 err:
334 slot = ERR_PTR(err);
335 goto out;
336 }
337 EXPORT_SYMBOL_GPL(pci_create_slot);
338
339 /**
340 * pci_destroy_slot - decrement refcount for physical PCI slot
341 * @slot: struct pci_slot to decrement
342 *
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
345 * rest.
346 */
pci_destroy_slot(struct pci_slot * slot)347 void pci_destroy_slot(struct pci_slot *slot)
348 {
349 dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
350 slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
351
352 mutex_lock(&pci_slot_mutex);
353 kobject_put(&slot->kobj);
354 mutex_unlock(&pci_slot_mutex);
355 }
356 EXPORT_SYMBOL_GPL(pci_destroy_slot);
357
358 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
359 #include <linux/pci_hotplug.h>
360 /**
361 * pci_hp_create_link - create symbolic link to the hotplug driver module.
362 * @pci_slot: struct pci_slot
363 *
364 * Helper function for pci_hotplug_core.c to create symbolic link to
365 * the hotplug driver module.
366 */
pci_hp_create_module_link(struct pci_slot * pci_slot)367 void pci_hp_create_module_link(struct pci_slot *pci_slot)
368 {
369 struct hotplug_slot *slot = pci_slot->hotplug;
370 struct kobject *kobj = NULL;
371 int ret;
372
373 if (!slot || !slot->ops)
374 return;
375 kobj = kset_find_obj(module_kset, slot->ops->mod_name);
376 if (!kobj)
377 return;
378 ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
379 if (ret)
380 dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
381 ret);
382 kobject_put(kobj);
383 }
384 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
385
386 /**
387 * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
388 * @pci_slot: struct pci_slot
389 *
390 * Helper function for pci_hotplug_core.c to remove symbolic link to
391 * the hotplug driver module.
392 */
pci_hp_remove_module_link(struct pci_slot * pci_slot)393 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
394 {
395 sysfs_remove_link(&pci_slot->kobj, "module");
396 }
397 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
398 #endif
399
pci_slot_init(void)400 static int pci_slot_init(void)
401 {
402 struct kset *pci_bus_kset;
403
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");
409 return -ENOMEM;
410 }
411 return 0;
412 }
413
414 subsys_initcall(pci_slot_init);
415