Revert "ACPI: video: Ignore devices that aren't present in hardware"
[linux-2.6/sactl.git] / drivers / pci / search.c
blob8541034021f0d5eaf168d83e425bb66d1b03a2e1
1 /*
2 * PCI searching functions.
4 * Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
5 * David Mosberger-Tang
6 * Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
7 * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
8 */
10 #include <linux/init.h>
11 #include <linux/pci.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include "pci.h"
16 DECLARE_RWSEM(pci_bus_sem);
18 * find the upstream PCIE-to-PCI bridge of a PCI device
19 * if the device is PCIE, return NULL
20 * if the device isn't connected to a PCIE bridge (that is its parent is a
21 * legacy PCI bridge and the bridge is directly connected to bus 0), return its
22 * parent
24 struct pci_dev *
25 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
27 struct pci_dev *tmp = NULL;
29 if (pdev->is_pcie)
30 return NULL;
31 while (1) {
32 if (!pdev->bus->self)
33 break;
34 pdev = pdev->bus->self;
35 /* a p2p bridge */
36 if (!pdev->is_pcie) {
37 tmp = pdev;
38 continue;
40 /* PCI device should connect to a PCIE bridge */
41 if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
42 /* Busted hardware? */
43 WARN_ON_ONCE(1);
44 return NULL;
46 return pdev;
49 return tmp;
52 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
54 struct pci_bus* child;
55 struct list_head *tmp;
57 if(bus->number == busnr)
58 return bus;
60 list_for_each(tmp, &bus->children) {
61 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
62 if(child)
63 return child;
65 return NULL;
68 /**
69 * pci_find_bus - locate PCI bus from a given domain and bus number
70 * @domain: number of PCI domain to search
71 * @busnr: number of desired PCI bus
73 * Given a PCI bus number and domain number, the desired PCI bus is located
74 * in the global list of PCI buses. If the bus is found, a pointer to its
75 * data structure is returned. If no bus is found, %NULL is returned.
77 struct pci_bus * pci_find_bus(int domain, int busnr)
79 struct pci_bus *bus = NULL;
80 struct pci_bus *tmp_bus;
82 while ((bus = pci_find_next_bus(bus)) != NULL) {
83 if (pci_domain_nr(bus) != domain)
84 continue;
85 tmp_bus = pci_do_find_bus(bus, busnr);
86 if (tmp_bus)
87 return tmp_bus;
89 return NULL;
92 /**
93 * pci_find_next_bus - begin or continue searching for a PCI bus
94 * @from: Previous PCI bus found, or %NULL for new search.
96 * Iterates through the list of known PCI busses. A new search is
97 * initiated by passing %NULL as the @from argument. Otherwise if
98 * @from is not %NULL, searches continue from next device on the
99 * global list.
101 struct pci_bus *
102 pci_find_next_bus(const struct pci_bus *from)
104 struct list_head *n;
105 struct pci_bus *b = NULL;
107 WARN_ON(in_interrupt());
108 down_read(&pci_bus_sem);
109 n = from ? from->node.next : pci_root_buses.next;
110 if (n != &pci_root_buses)
111 b = pci_bus_b(n);
112 up_read(&pci_bus_sem);
113 return b;
116 #ifdef CONFIG_PCI_LEGACY
119 * pci_find_slot - locate PCI device from a given PCI slot
120 * @bus: number of PCI bus on which desired PCI device resides
121 * @devfn: encodes number of PCI slot in which the desired PCI
122 * device resides and the logical device number within that slot
123 * in case of multi-function devices.
125 * Given a PCI bus and slot/function number, the desired PCI device
126 * is located in system global list of PCI devices. If the device
127 * is found, a pointer to its data structure is returned. If no
128 * device is found, %NULL is returned.
130 struct pci_dev *
131 pci_find_slot(unsigned int bus, unsigned int devfn)
133 struct pci_dev *dev = NULL;
135 while ((dev = pci_find_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
136 if (dev->bus->number == bus && dev->devfn == devfn)
137 return dev;
139 return NULL;
142 #endif /* CONFIG_PCI_LEGACY */
145 * pci_get_slot - locate PCI device for a given PCI slot
146 * @bus: PCI bus on which desired PCI device resides
147 * @devfn: encodes number of PCI slot in which the desired PCI
148 * device resides and the logical device number within that slot
149 * in case of multi-function devices.
151 * Given a PCI bus and slot/function number, the desired PCI device
152 * is located in the list of PCI devices.
153 * If the device is found, its reference count is increased and this
154 * function returns a pointer to its data structure. The caller must
155 * decrement the reference count by calling pci_dev_put().
156 * If no device is found, %NULL is returned.
158 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
160 struct list_head *tmp;
161 struct pci_dev *dev;
163 WARN_ON(in_interrupt());
164 down_read(&pci_bus_sem);
166 list_for_each(tmp, &bus->devices) {
167 dev = pci_dev_b(tmp);
168 if (dev->devfn == devfn)
169 goto out;
172 dev = NULL;
173 out:
174 pci_dev_get(dev);
175 up_read(&pci_bus_sem);
176 return dev;
180 * pci_get_bus_and_slot - locate PCI device from a given PCI bus & slot
181 * @bus: number of PCI bus on which desired PCI device resides
182 * @devfn: encodes number of PCI slot in which the desired PCI
183 * device resides and the logical device number within that slot
184 * in case of multi-function devices.
186 * Note: the bus/slot search is limited to PCI domain (segment) 0.
188 * Given a PCI bus and slot/function number, the desired PCI device
189 * is located in system global list of PCI devices. If the device
190 * is found, a pointer to its data structure is returned. If no
191 * device is found, %NULL is returned. The returned device has its
192 * reference count bumped by one.
195 struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
197 struct pci_dev *dev = NULL;
199 while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
200 if (pci_domain_nr(dev->bus) == 0 &&
201 (dev->bus->number == bus && dev->devfn == devfn))
202 return dev;
204 return NULL;
207 #ifdef CONFIG_PCI_LEGACY
209 * pci_find_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
210 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
211 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
212 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
213 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
214 * @from: Previous PCI device found in search, or %NULL for new search.
216 * Iterates through the list of known PCI devices. If a PCI device is
217 * found with a matching @vendor, @device, @ss_vendor and @ss_device, a
218 * pointer to its device structure is returned. Otherwise, %NULL is returned.
219 * A new search is initiated by passing %NULL as the @from argument.
220 * Otherwise if @from is not %NULL, searches continue from next device
221 * on the global list.
223 * NOTE: Do not use this function any more; use pci_get_subsys() instead, as
224 * the PCI device returned by this function can disappear at any moment in
225 * time.
227 static struct pci_dev * pci_find_subsys(unsigned int vendor,
228 unsigned int device,
229 unsigned int ss_vendor,
230 unsigned int ss_device,
231 const struct pci_dev *from)
233 struct list_head *n;
234 struct pci_dev *dev;
236 WARN_ON(in_interrupt());
239 * pci_find_subsys() can be called on the ide_setup() path, super-early
240 * in boot. But the down_read() will enable local interrupts, which
241 * can cause some machines to crash. So here we detect and flag that
242 * situation and bail out early.
244 if (unlikely(no_pci_devices()))
245 return NULL;
246 down_read(&pci_bus_sem);
247 n = from ? from->global_list.next : pci_devices.next;
249 while (n && (n != &pci_devices)) {
250 dev = pci_dev_g(n);
251 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
252 (device == PCI_ANY_ID || dev->device == device) &&
253 (ss_vendor == PCI_ANY_ID || dev->subsystem_vendor == ss_vendor) &&
254 (ss_device == PCI_ANY_ID || dev->subsystem_device == ss_device))
255 goto exit;
256 n = n->next;
258 dev = NULL;
259 exit:
260 up_read(&pci_bus_sem);
261 return dev;
265 * pci_find_device - begin or continue searching for a PCI device by vendor/device id
266 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
267 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
268 * @from: Previous PCI device found in search, or %NULL for new search.
270 * Iterates through the list of known PCI devices. If a PCI device is found
271 * with a matching @vendor and @device, a pointer to its device structure is
272 * returned. Otherwise, %NULL is returned.
273 * A new search is initiated by passing %NULL as the @from argument.
274 * Otherwise if @from is not %NULL, searches continue from next device
275 * on the global list.
277 * NOTE: Do not use this function any more; use pci_get_device() instead, as
278 * the PCI device returned by this function can disappear at any moment in
279 * time.
281 struct pci_dev *
282 pci_find_device(unsigned int vendor, unsigned int device, const struct pci_dev *from)
284 return pci_find_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
286 #endif /* CONFIG_PCI_LEGACY */
289 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
290 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
291 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
292 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
293 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
294 * @from: Previous PCI device found in search, or %NULL for new search.
296 * Iterates through the list of known PCI devices. If a PCI device is found
297 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
298 * device structure is returned, and the reference count to the device is
299 * incremented. Otherwise, %NULL is returned. A new search is initiated by
300 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
301 * searches continue from next device on the global list.
302 * The reference count for @from is always decremented if it is not %NULL.
304 struct pci_dev *
305 pci_get_subsys(unsigned int vendor, unsigned int device,
306 unsigned int ss_vendor, unsigned int ss_device,
307 struct pci_dev *from)
309 struct list_head *n;
310 struct pci_dev *dev;
312 WARN_ON(in_interrupt());
315 * pci_get_subsys() can potentially be called by drivers super-early
316 * in boot. But the down_read() will enable local interrupts, which
317 * can cause some machines to crash. So here we detect and flag that
318 * situation and bail out early.
320 if (unlikely(no_pci_devices()))
321 return NULL;
322 down_read(&pci_bus_sem);
323 n = from ? from->global_list.next : pci_devices.next;
325 while (n && (n != &pci_devices)) {
326 dev = pci_dev_g(n);
327 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
328 (device == PCI_ANY_ID || dev->device == device) &&
329 (ss_vendor == PCI_ANY_ID || dev->subsystem_vendor == ss_vendor) &&
330 (ss_device == PCI_ANY_ID || dev->subsystem_device == ss_device))
331 goto exit;
332 n = n->next;
334 dev = NULL;
335 exit:
336 dev = pci_dev_get(dev);
337 up_read(&pci_bus_sem);
338 pci_dev_put(from);
339 return dev;
343 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
344 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
345 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
346 * @from: Previous PCI device found in search, or %NULL for new search.
348 * Iterates through the list of known PCI devices. If a PCI device is
349 * found with a matching @vendor and @device, the reference count to the
350 * device is incremented and a pointer to its device structure is returned.
351 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
352 * as the @from argument. Otherwise if @from is not %NULL, searches continue
353 * from next device on the global list. The reference count for @from is
354 * always decremented if it is not %NULL.
356 struct pci_dev *
357 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
359 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
363 * pci_get_device_reverse - begin or continue searching for a PCI device by vendor/device id
364 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
365 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
366 * @from: Previous PCI device found in search, or %NULL for new search.
368 * Iterates through the list of known PCI devices in the reverse order of
369 * pci_get_device.
370 * If a PCI device is found with a matching @vendor and @device, the reference
371 * count to the device is incremented and a pointer to its device structure
372 * is returned Otherwise, %NULL is returned. A new search is initiated by
373 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
374 * searches continue from next device on the global list. The reference
375 * count for @from is always decremented if it is not %NULL.
377 struct pci_dev *
378 pci_get_device_reverse(unsigned int vendor, unsigned int device, struct pci_dev *from)
380 struct list_head *n;
381 struct pci_dev *dev;
383 WARN_ON(in_interrupt());
384 down_read(&pci_bus_sem);
385 n = from ? from->global_list.prev : pci_devices.prev;
387 while (n && (n != &pci_devices)) {
388 dev = pci_dev_g(n);
389 if ((vendor == PCI_ANY_ID || dev->vendor == vendor) &&
390 (device == PCI_ANY_ID || dev->device == device))
391 goto exit;
392 n = n->prev;
394 dev = NULL;
395 exit:
396 dev = pci_dev_get(dev);
397 up_read(&pci_bus_sem);
398 pci_dev_put(from);
399 return dev;
403 * pci_get_class - begin or continue searching for a PCI device by class
404 * @class: search for a PCI device with this class designation
405 * @from: Previous PCI device found in search, or %NULL for new search.
407 * Iterates through the list of known PCI devices. If a PCI device is
408 * found with a matching @class, the reference count to the device is
409 * incremented and a pointer to its device structure is returned.
410 * Otherwise, %NULL is returned.
411 * A new search is initiated by passing %NULL as the @from argument.
412 * Otherwise if @from is not %NULL, searches continue from next device
413 * on the global list. The reference count for @from is always decremented
414 * if it is not %NULL.
416 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
418 struct list_head *n;
419 struct pci_dev *dev;
421 WARN_ON(in_interrupt());
422 down_read(&pci_bus_sem);
423 n = from ? from->global_list.next : pci_devices.next;
425 while (n && (n != &pci_devices)) {
426 dev = pci_dev_g(n);
427 if (dev->class == class)
428 goto exit;
429 n = n->next;
431 dev = NULL;
432 exit:
433 dev = pci_dev_get(dev);
434 up_read(&pci_bus_sem);
435 pci_dev_put(from);
436 return dev;
439 const struct pci_device_id *pci_find_present(const struct pci_device_id *ids)
441 struct pci_dev *dev;
442 const struct pci_device_id *found = NULL;
444 WARN_ON(in_interrupt());
445 down_read(&pci_bus_sem);
446 while (ids->vendor || ids->subvendor || ids->class_mask) {
447 list_for_each_entry(dev, &pci_devices, global_list) {
448 if ((found = pci_match_one_device(ids, dev)) != NULL)
449 goto exit;
451 ids++;
453 exit:
454 up_read(&pci_bus_sem);
455 return found;
459 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
460 * @ids: A pointer to a null terminated list of struct pci_device_id structures
461 * that describe the type of PCI device the caller is trying to find.
463 * Obvious fact: You do not have a reference to any device that might be found
464 * by this function, so if that device is removed from the system right after
465 * this function is finished, the value will be stale. Use this function to
466 * find devices that are usually built into a system, or for a general hint as
467 * to if another device happens to be present at this specific moment in time.
469 int pci_dev_present(const struct pci_device_id *ids)
471 return pci_find_present(ids) == NULL ? 0 : 1;
474 EXPORT_SYMBOL(pci_dev_present);
475 EXPORT_SYMBOL(pci_find_present);
477 #ifdef CONFIG_PCI_LEGACY
478 EXPORT_SYMBOL(pci_find_device);
479 EXPORT_SYMBOL(pci_find_slot);
480 #endif /* CONFIG_PCI_LEGACY */
482 /* For boot time work */
483 EXPORT_SYMBOL(pci_find_bus);
484 EXPORT_SYMBOL(pci_find_next_bus);
485 /* For everyone */
486 EXPORT_SYMBOL(pci_get_device);
487 EXPORT_SYMBOL(pci_get_device_reverse);
488 EXPORT_SYMBOL(pci_get_subsys);
489 EXPORT_SYMBOL(pci_get_slot);
490 EXPORT_SYMBOL(pci_get_bus_and_slot);
491 EXPORT_SYMBOL(pci_get_class);