Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / drivers / pci / search.c
blob9d75dc8ca602995826b80c842e40edfea1a2d866
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/slab.h>
13 #include <linux/module.h>
14 #include <linux/interrupt.h>
15 #include "pci.h"
17 DECLARE_RWSEM(pci_bus_sem);
19 * find the upstream PCIe-to-PCI bridge of a PCI device
20 * if the device is PCIE, return NULL
21 * if the device isn't connected to a PCIe bridge (that is its parent is a
22 * legacy PCI bridge and the bridge is directly connected to bus 0), return its
23 * parent
25 struct pci_dev *
26 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
28 struct pci_dev *tmp = NULL;
30 if (pci_is_pcie(pdev))
31 return NULL;
32 while (1) {
33 if (pci_is_root_bus(pdev->bus))
34 break;
35 pdev = pdev->bus->self;
36 /* a p2p bridge */
37 if (!pci_is_pcie(pdev)) {
38 tmp = pdev;
39 continue;
41 /* PCI device should connect to a PCIe bridge */
42 if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
43 /* Busted hardware? */
44 WARN_ON_ONCE(1);
45 return NULL;
47 return pdev;
50 return tmp;
53 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
55 struct pci_bus* child;
56 struct list_head *tmp;
58 if(bus->number == busnr)
59 return bus;
61 list_for_each(tmp, &bus->children) {
62 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
63 if(child)
64 return child;
66 return NULL;
69 /**
70 * pci_find_bus - locate PCI bus from a given domain and bus number
71 * @domain: number of PCI domain to search
72 * @busnr: number of desired PCI bus
74 * Given a PCI bus number and domain number, the desired PCI bus is located
75 * in the global list of PCI buses. If the bus is found, a pointer to its
76 * data structure is returned. If no bus is found, %NULL is returned.
78 struct pci_bus * pci_find_bus(int domain, int busnr)
80 struct pci_bus *bus = NULL;
81 struct pci_bus *tmp_bus;
83 while ((bus = pci_find_next_bus(bus)) != NULL) {
84 if (pci_domain_nr(bus) != domain)
85 continue;
86 tmp_bus = pci_do_find_bus(bus, busnr);
87 if (tmp_bus)
88 return tmp_bus;
90 return NULL;
93 /**
94 * pci_find_next_bus - begin or continue searching for a PCI bus
95 * @from: Previous PCI bus found, or %NULL for new search.
97 * Iterates through the list of known PCI busses. A new search is
98 * initiated by passing %NULL as the @from argument. Otherwise if
99 * @from is not %NULL, searches continue from next device on the
100 * global list.
102 struct pci_bus *
103 pci_find_next_bus(const struct pci_bus *from)
105 struct list_head *n;
106 struct pci_bus *b = NULL;
108 WARN_ON(in_interrupt());
109 down_read(&pci_bus_sem);
110 n = from ? from->node.next : pci_root_buses.next;
111 if (n != &pci_root_buses)
112 b = pci_bus_b(n);
113 up_read(&pci_bus_sem);
114 return b;
118 * pci_get_slot - locate PCI device for a given PCI slot
119 * @bus: PCI bus on which desired PCI device resides
120 * @devfn: encodes number of PCI slot in which the desired PCI
121 * device resides and the logical device number within that slot
122 * in case of multi-function devices.
124 * Given a PCI bus and slot/function number, the desired PCI device
125 * is located in the list of PCI devices.
126 * If the device is found, its reference count is increased and this
127 * function returns a pointer to its data structure. The caller must
128 * decrement the reference count by calling pci_dev_put().
129 * If no device is found, %NULL is returned.
131 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
133 struct list_head *tmp;
134 struct pci_dev *dev;
136 WARN_ON(in_interrupt());
137 down_read(&pci_bus_sem);
139 list_for_each(tmp, &bus->devices) {
140 dev = pci_dev_b(tmp);
141 if (dev->devfn == devfn)
142 goto out;
145 dev = NULL;
146 out:
147 pci_dev_get(dev);
148 up_read(&pci_bus_sem);
149 return dev;
153 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
154 * @domain: PCI domain/segment on which the PCI device resides.
155 * @bus: PCI bus on which desired PCI device resides
156 * @devfn: encodes number of PCI slot in which the desired PCI device
157 * resides and the logical device number within that slot in case of
158 * multi-function devices.
160 * Given a PCI domain, bus, and slot/function number, the desired PCI
161 * device is located in the list of PCI devices. If the device is
162 * found, its reference count is increased and this function returns a
163 * pointer to its data structure. The caller must decrement the
164 * reference count by calling pci_dev_put(). If no device is found,
165 * %NULL is returned.
167 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
168 unsigned int devfn)
170 struct pci_dev *dev = NULL;
172 for_each_pci_dev(dev) {
173 if (pci_domain_nr(dev->bus) == domain &&
174 (dev->bus->number == bus && dev->devfn == devfn))
175 return dev;
177 return NULL;
179 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
181 static int match_pci_dev_by_id(struct device *dev, void *data)
183 struct pci_dev *pdev = to_pci_dev(dev);
184 struct pci_device_id *id = data;
186 if (pci_match_one_device(id, pdev))
187 return 1;
188 return 0;
192 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
193 * @id: pointer to struct pci_device_id to match for the device
194 * @from: Previous PCI device found in search, or %NULL for new search.
196 * Iterates through the list of known PCI devices. If a PCI device is found
197 * with a matching id a pointer to its device structure is returned, and the
198 * reference count to the device is incremented. Otherwise, %NULL is returned.
199 * A new search is initiated by passing %NULL as the @from argument. Otherwise
200 * if @from is not %NULL, searches continue from next device on the global
201 * list. The reference count for @from is always decremented if it is not
202 * %NULL.
204 * This is an internal function for use by the other search functions in
205 * this file.
207 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
208 struct pci_dev *from)
210 struct device *dev;
211 struct device *dev_start = NULL;
212 struct pci_dev *pdev = NULL;
214 WARN_ON(in_interrupt());
215 if (from)
216 dev_start = &from->dev;
217 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
218 match_pci_dev_by_id);
219 if (dev)
220 pdev = to_pci_dev(dev);
221 if (from)
222 pci_dev_put(from);
223 return pdev;
227 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
228 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
229 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
230 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
231 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
232 * @from: Previous PCI device found in search, or %NULL for new search.
234 * Iterates through the list of known PCI devices. If a PCI device is found
235 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
236 * device structure is returned, and the reference count to the device is
237 * incremented. Otherwise, %NULL is returned. A new search is initiated by
238 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
239 * searches continue from next device on the global list.
240 * The reference count for @from is always decremented if it is not %NULL.
242 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
243 unsigned int ss_vendor, unsigned int ss_device,
244 struct pci_dev *from)
246 struct pci_dev *pdev;
247 struct pci_device_id *id;
250 * pci_find_subsys() can be called on the ide_setup() path,
251 * super-early in boot. But the down_read() will enable local
252 * interrupts, which can cause some machines to crash. So here we
253 * detect and flag that situation and bail out early.
255 if (unlikely(no_pci_devices()))
256 return NULL;
258 id = kzalloc(sizeof(*id), GFP_KERNEL);
259 if (!id)
260 return NULL;
261 id->vendor = vendor;
262 id->device = device;
263 id->subvendor = ss_vendor;
264 id->subdevice = ss_device;
266 pdev = pci_get_dev_by_id(id, from);
267 kfree(id);
269 return pdev;
273 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
274 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
275 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
276 * @from: Previous PCI device found in search, or %NULL for new search.
278 * Iterates through the list of known PCI devices. If a PCI device is
279 * found with a matching @vendor and @device, the reference count to the
280 * device is incremented and a pointer to its device structure is returned.
281 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
282 * as the @from argument. Otherwise if @from is not %NULL, searches continue
283 * from next device on the global list. The reference count for @from is
284 * always decremented if it is not %NULL.
286 struct pci_dev *
287 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
289 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
293 * pci_get_class - begin or continue searching for a PCI device by class
294 * @class: search for a PCI device with this class designation
295 * @from: Previous PCI device found in search, or %NULL for new search.
297 * Iterates through the list of known PCI devices. If a PCI device is
298 * found with a matching @class, the reference count to the device is
299 * incremented and a pointer to its device structure is returned.
300 * Otherwise, %NULL is returned.
301 * A new search is initiated by passing %NULL as the @from argument.
302 * Otherwise if @from is not %NULL, searches continue from next device
303 * on the global list. The reference count for @from is always decremented
304 * if it is not %NULL.
306 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
308 struct pci_dev *dev;
309 struct pci_device_id *id;
311 id = kzalloc(sizeof(*id), GFP_KERNEL);
312 if (!id)
313 return NULL;
314 id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
315 id->class_mask = PCI_ANY_ID;
316 id->class = class;
318 dev = pci_get_dev_by_id(id, from);
319 kfree(id);
320 return dev;
324 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
325 * @ids: A pointer to a null terminated list of struct pci_device_id structures
326 * that describe the type of PCI device the caller is trying to find.
328 * Obvious fact: You do not have a reference to any device that might be found
329 * by this function, so if that device is removed from the system right after
330 * this function is finished, the value will be stale. Use this function to
331 * find devices that are usually built into a system, or for a general hint as
332 * to if another device happens to be present at this specific moment in time.
334 int pci_dev_present(const struct pci_device_id *ids)
336 struct pci_dev *found = NULL;
338 WARN_ON(in_interrupt());
339 while (ids->vendor || ids->subvendor || ids->class_mask) {
340 found = pci_get_dev_by_id(ids, NULL);
341 if (found)
342 goto exit;
343 ids++;
345 exit:
346 if (found)
347 return 1;
348 return 0;
350 EXPORT_SYMBOL(pci_dev_present);
352 /* For boot time work */
353 EXPORT_SYMBOL(pci_find_bus);
354 EXPORT_SYMBOL(pci_find_next_bus);
355 /* For everyone */
356 EXPORT_SYMBOL(pci_get_device);
357 EXPORT_SYMBOL(pci_get_subsys);
358 EXPORT_SYMBOL(pci_get_slot);
359 EXPORT_SYMBOL(pci_get_class);