xref: /openbmc/linux/drivers/pci/slot.c (revision 930beb5a)
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 
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 
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 
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 };
78 
79 static 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 
91 static 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 
96 static 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 
101 static 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 
118 static struct pci_slot_attribute pci_slot_attr_address =
119 	__ATTR(address, (S_IFREG | S_IRUGO), address_read_file, NULL);
120 static struct pci_slot_attribute pci_slot_attr_max_speed =
121 	__ATTR(max_bus_speed, (S_IFREG | S_IRUGO), max_speed_read_file, NULL);
122 static struct pci_slot_attribute pci_slot_attr_cur_speed =
123 	__ATTR(cur_bus_speed, (S_IFREG | S_IRUGO), cur_speed_read_file, NULL);
124 
125 static 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 
132 static 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 
138 static 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 
176 static 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 
194 static 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  */
247 struct 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 
278 placeholder:
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 
311 out:
312 	kfree(slot_name);
313 	up_write(&pci_bus_sem);
314 	return slot;
315 err:
316 	kfree(slot);
317 	slot = ERR_PTR(err);
318 	goto out;
319 }
320 EXPORT_SYMBOL_GPL(pci_create_slot);
321 
322 /**
323  * pci_renumber_slot - update %struct pci_slot -> number
324  * @slot: &struct pci_slot to update
325  * @slot_nr: new number for slot
326  *
327  * The primary purpose of this interface is to allow callers who earlier
328  * created a placeholder slot in pci_create_slot() by passing a -1 as
329  * slot_nr, to update their %struct pci_slot with the correct @slot_nr.
330  */
331 void pci_renumber_slot(struct pci_slot *slot, int slot_nr)
332 {
333 	struct pci_slot *tmp;
334 
335 	down_write(&pci_bus_sem);
336 
337 	list_for_each_entry(tmp, &slot->bus->slots, list) {
338 		WARN_ON(tmp->number == slot_nr);
339 		goto out;
340 	}
341 
342 	slot->number = slot_nr;
343 out:
344 	up_write(&pci_bus_sem);
345 }
346 EXPORT_SYMBOL_GPL(pci_renumber_slot);
347 
348 /**
349  * pci_destroy_slot - decrement refcount for physical PCI slot
350  * @slot: struct pci_slot to decrement
351  *
352  * %struct pci_slot is refcounted, so destroying them is really easy; we
353  * just call kobject_put on its kobj and let our release methods do the
354  * rest.
355  */
356 void pci_destroy_slot(struct pci_slot *slot)
357 {
358 	dev_dbg(&slot->bus->dev, "dev %02x, dec refcount to %d\n",
359 		slot->number, atomic_read(&slot->kobj.kref.refcount) - 1);
360 
361 	down_write(&pci_bus_sem);
362 	kobject_put(&slot->kobj);
363 	up_write(&pci_bus_sem);
364 }
365 EXPORT_SYMBOL_GPL(pci_destroy_slot);
366 
367 #if defined(CONFIG_HOTPLUG_PCI) || defined(CONFIG_HOTPLUG_PCI_MODULE)
368 #include <linux/pci_hotplug.h>
369 /**
370  * pci_hp_create_link - create symbolic link to the hotplug driver module.
371  * @pci_slot: struct pci_slot
372  *
373  * Helper function for pci_hotplug_core.c to create symbolic link to
374  * the hotplug driver module.
375  */
376 void pci_hp_create_module_link(struct pci_slot *pci_slot)
377 {
378 	struct hotplug_slot *slot = pci_slot->hotplug;
379 	struct kobject *kobj = NULL;
380 	int ret;
381 
382 	if (!slot || !slot->ops)
383 		return;
384 	kobj = kset_find_obj(module_kset, slot->ops->mod_name);
385 	if (!kobj)
386 		return;
387 	ret = sysfs_create_link(&pci_slot->kobj, kobj, "module");
388 	if (ret)
389 		dev_err(&pci_slot->bus->dev, "Error creating sysfs link (%d)\n",
390 			ret);
391 	kobject_put(kobj);
392 }
393 EXPORT_SYMBOL_GPL(pci_hp_create_module_link);
394 
395 /**
396  * pci_hp_remove_link - remove symbolic link to the hotplug driver module.
397  * @pci_slot: struct pci_slot
398  *
399  * Helper function for pci_hotplug_core.c to remove symbolic link to
400  * the hotplug driver module.
401  */
402 void pci_hp_remove_module_link(struct pci_slot *pci_slot)
403 {
404 	sysfs_remove_link(&pci_slot->kobj, "module");
405 }
406 EXPORT_SYMBOL_GPL(pci_hp_remove_module_link);
407 #endif
408 
409 static int pci_slot_init(void)
410 {
411 	struct kset *pci_bus_kset;
412 
413 	pci_bus_kset = bus_get_kset(&pci_bus_type);
414 	pci_slots_kset = kset_create_and_add("slots", NULL,
415 						&pci_bus_kset->kobj);
416 	if (!pci_slots_kset) {
417 		printk(KERN_ERR "PCI: Slot initialization failure\n");
418 		return -ENOMEM;
419 	}
420 	return 0;
421 }
422 
423 subsys_initcall(pci_slot_init);
424