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 
pci_slot_attr_show(struct kobject * kobj,struct attribute * attr,char * buf)18 static 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 
pci_slot_attr_store(struct kobject * kobj,struct attribute * attr,const char * buf,size_t len)26 static 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 
34 static const struct sysfs_ops pci_slot_sysfs_ops = {
35 	.show = pci_slot_attr_show,
36 	.store = pci_slot_attr_store,
37 };
38 
address_read_file(struct pci_slot * slot,char * buf)39 static 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 */
53 static 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 
bus_speed_read(enum pci_bus_speed speed,char * buf)81 static 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 
max_speed_read_file(struct pci_slot * slot,char * buf)93 static 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 
cur_speed_read_file(struct pci_slot * slot,char * buf)98 static 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 
pci_slot_release(struct kobject * kobj)103 static 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 
122 static struct pci_slot_attribute pci_slot_attr_address =
123 	__ATTR(address, S_IRUGO, address_read_file, NULL);
124 static struct pci_slot_attribute pci_slot_attr_max_speed =
125 	__ATTR(max_bus_speed, S_IRUGO, max_speed_read_file, NULL);
126 static struct pci_slot_attribute pci_slot_attr_cur_speed =
127 	__ATTR(cur_bus_speed, S_IRUGO, cur_speed_read_file, NULL);
128 
129 static 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 
136 static 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 
make_slot_name(const char * name)142 static 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 
rename_slot(struct pci_slot * slot,const char * name)180 static 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 
pci_dev_assign_slot(struct pci_dev * dev)198 void 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 
get_slot(struct pci_bus * parent,int slot_nr)209 static 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  */
pci_create_slot(struct pci_bus * parent,int slot_nr,const char * name,struct hotplug_slot * hotplug)261 struct 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 
292 placeholder:
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 		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 		kobject_put(&slot->kobj);
318 		goto err;
319 	}
320 
321 	down_read(&pci_bus_sem);
322 	list_for_each_entry(dev, &parent->devices, bus_list)
323 		if (PCI_SLOT(dev->devfn) == slot_nr)
324 			dev->slot = slot;
325 	up_read(&pci_bus_sem);
326 
327 	dev_dbg(&parent->dev, "dev %02x, created physical slot %s\n",
328 		slot_nr, pci_slot_name(slot));
329 
330 out:
331 	kfree(slot_name);
332 	mutex_unlock(&pci_slot_mutex);
333 	return slot;
334 err:
335 	slot = ERR_PTR(err);
336 	goto out;
337 }
338 EXPORT_SYMBOL_GPL(pci_create_slot);
339 
340 /**
341  * pci_destroy_slot - decrement refcount for physical PCI slot
342  * @slot: struct pci_slot to decrement
343  *
344  * %struct pci_slot is refcounted, so destroying them is really easy; we
345  * just call kobject_put on its kobj and let our release methods do the
346  * rest.
347  */
pci_destroy_slot(struct pci_slot * slot)348 void pci_destroy_slot(struct pci_slot *slot)
349 {
350 	dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
351 		slot->number, kref_read(&slot->kobj.kref) - 1);
352 
353 	mutex_lock(&pci_slot_mutex);
354 	kobject_put(&slot->kobj);
355 	mutex_unlock(&pci_slot_mutex);
356 }
357 EXPORT_SYMBOL_GPL(pci_destroy_slot);
358 
359 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
360 #include <linux/pci_hotplug.h>
361 /**
362  * pci_hp_create_link - create symbolic link to the hotplug driver module.
363  * @pci_slot: struct pci_slot
364  *
365  * Helper function for pci_hotplug_core.c to create symbolic link to
366  * the hotplug driver module.
367  */
pci_hp_create_module_link(struct pci_slot * pci_slot)368 void pci_hp_create_module_link(struct pci_slot *pci_slot)
369 {
370 	struct hotplug_slot *slot = pci_slot->hotplug;
371 	struct kobject *kobj = NULL;
372 	int ret;
373 
374 	if (!slot || !slot->ops)
375 		return;
376 	kobj = kset_find_obj(module_kset, slot->ops->mod_name);
377 	if (!kobj)
378 		return;
379 	ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
380 	if (ret)
381 		dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
382 			ret);
383 	kobject_put(kobj);
384 }
385 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
386 
387 /**
388  * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
389  * @pci_slot: struct pci_slot
390  *
391  * Helper function for pci_hotplug_core.c to remove symbolic link to
392  * the hotplug driver module.
393  */
pci_hp_remove_module_link(struct pci_slot * pci_slot)394 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
395 {
396 	sysfs_remove_link(&pci_slot->kobj, "module");
397 }
398 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
399 #endif
400 
pci_slot_init(void)401 static int pci_slot_init(void)
402 {
403 	struct kset *pci_bus_kset;
404 
405 	pci_bus_kset = bus_get_kset(&pci_bus_type);
406 	pci_slots_kset = kset_create_and_add("slots", NULL,
407 						&pci_bus_kset->kobj);
408 	if (!pci_slots_kset) {
409 		printk(KERN_ERR "PCI: Slot initialization failure\n");
410 		return -ENOMEM;
411 	}
412 	return 0;
413 }
414 
415 subsys_initcall(pci_slot_init);
416