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1/*
2 * PCI searching functions.
3 *
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 */
9
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"
16
17DECLARE_RWSEM(pci_bus_sem);
18/*
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
24 */
25struct pci_dev *
26pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
27{
28 struct pci_dev *tmp = NULL;
29
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;
40 }
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;
46 }
47 return pdev;
48 }
49
50 return tmp;
51}
52
53static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
54{
55 struct pci_bus* child;
56 struct list_head *tmp;
57
58 if(bus->number == busnr)
59 return bus;
60
61 list_for_each(tmp, &bus->children) {
62 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
63 if(child)
64 return child;
65 }
66 return NULL;
67}
68
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
73 *
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.
77 */
78struct pci_bus * pci_find_bus(int domain, int busnr)
79{
80 struct pci_bus *bus = NULL;
81 struct pci_bus *tmp_bus;
82
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;
89 }
90 return NULL;
91}
92
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.
96 *
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.
101 */
102struct pci_bus *
103pci_find_next_bus(const struct pci_bus *from)
104{
105 struct list_head *n;
106 struct pci_bus *b = NULL;
107
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;
115}
116
117/**
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.
123 *
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.
130 */
131struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
132{
133 struct list_head *tmp;
134 struct pci_dev *dev;
135
136 WARN_ON(in_interrupt());
137 down_read(&pci_bus_sem);
138
139 list_for_each(tmp, &bus->devices) {
140 dev = pci_dev_b(tmp);
141 if (dev->devfn == devfn)
142 goto out;
143 }
144
145 dev = NULL;
146 out:
147 pci_dev_get(dev);
148 up_read(&pci_bus_sem);
149 return dev;
150}
151
152/**
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.
159 *
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.
166 */
167struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
168 unsigned int devfn)
169{
170 struct pci_dev *dev = NULL;
171
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;
176 }
177 return NULL;
178}
179EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
180
181static int match_pci_dev_by_id(struct device *dev, void *data)
182{
183 struct pci_dev *pdev = to_pci_dev(dev);
184 struct pci_device_id *id = data;
185
186 if (pci_match_one_device(id, pdev))
187 return 1;
188 return 0;
189}
190
191/*
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.
195 *
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.
203 *
204 * This is an internal function for use by the other search functions in
205 * this file.
206 */
207static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
208 struct pci_dev *from)
209{
210 struct device *dev;
211 struct device *dev_start = NULL;
212 struct pci_dev *pdev = NULL;
213
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;
224}
225
226/**
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.
233 *
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.
241 */
242struct 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)
245{
246 struct pci_dev *pdev;
247 struct pci_device_id *id;
248
249 /*
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.
254 */
255 if (unlikely(no_pci_devices()))
256 return NULL;
257
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;
265
266 pdev = pci_get_dev_by_id(id, from);
267 kfree(id);
268
269 return pdev;
270}
271
272/**
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.
277 *
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.
285 */
286struct pci_dev *
287pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
288{
289 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
290}
291
292/**
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.
296 *
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.
305 */
306struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
307{
308 struct pci_dev *dev;
309 struct pci_device_id *id;
310
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;
317
318 dev = pci_get_dev_by_id(id, from);
319 kfree(id);
320 return dev;
321}
322
323/**
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.
327 *
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.
333 */
334int pci_dev_present(const struct pci_device_id *ids)
335{
336 struct pci_dev *found = NULL;
337
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++;
344 }
345exit:
346 if (found)
347 return 1;
348 return 0;
349}
350EXPORT_SYMBOL(pci_dev_present);
351
352/* For boot time work */
353EXPORT_SYMBOL(pci_find_bus);
354EXPORT_SYMBOL(pci_find_next_bus);
355/* For everyone */
356EXPORT_SYMBOL(pci_get_device);
357EXPORT_SYMBOL(pci_get_subsys);
358EXPORT_SYMBOL(pci_get_slot);
359EXPORT_SYMBOL(pci_get_class);
1/*
2 * PCI searching functions.
3 *
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 */
9
10#include <linux/pci.h>
11#include <linux/slab.h>
12#include <linux/module.h>
13#include <linux/interrupt.h>
14#include "pci.h"
15
16DECLARE_RWSEM(pci_bus_sem);
17EXPORT_SYMBOL_GPL(pci_bus_sem);
18
19/*
20 * pci_for_each_dma_alias - Iterate over DMA aliases for a device
21 * @pdev: starting downstream device
22 * @fn: function to call for each alias
23 * @data: opaque data to pass to @fn
24 *
25 * Starting @pdev, walk up the bus calling @fn for each possible alias
26 * of @pdev at the root bus.
27 */
28int pci_for_each_dma_alias(struct pci_dev *pdev,
29 int (*fn)(struct pci_dev *pdev,
30 u16 alias, void *data), void *data)
31{
32 struct pci_bus *bus;
33 int ret;
34
35 ret = fn(pdev, PCI_DEVID(pdev->bus->number, pdev->devfn), data);
36 if (ret)
37 return ret;
38
39 /*
40 * If the device is broken and uses an alias requester ID for
41 * DMA, iterate over that too.
42 */
43 if (unlikely(pdev->dev_flags & PCI_DEV_FLAGS_DMA_ALIAS_DEVFN)) {
44 ret = fn(pdev, PCI_DEVID(pdev->bus->number,
45 pdev->dma_alias_devfn), data);
46 if (ret)
47 return ret;
48 }
49
50 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
51 struct pci_dev *tmp;
52
53 /* Skip virtual buses */
54 if (!bus->self)
55 continue;
56
57 tmp = bus->self;
58
59 /*
60 * PCIe-to-PCI/X bridges alias transactions from downstream
61 * devices using the subordinate bus number (PCI Express to
62 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases
63 * where the upstream bus is PCI/X we alias to the bridge
64 * (there are various conditions in the previous reference
65 * where the bridge may take ownership of transactions, even
66 * when the secondary interface is PCI-X).
67 */
68 if (pci_is_pcie(tmp)) {
69 switch (pci_pcie_type(tmp)) {
70 case PCI_EXP_TYPE_ROOT_PORT:
71 case PCI_EXP_TYPE_UPSTREAM:
72 case PCI_EXP_TYPE_DOWNSTREAM:
73 continue;
74 case PCI_EXP_TYPE_PCI_BRIDGE:
75 ret = fn(tmp,
76 PCI_DEVID(tmp->subordinate->number,
77 PCI_DEVFN(0, 0)), data);
78 if (ret)
79 return ret;
80 continue;
81 case PCI_EXP_TYPE_PCIE_BRIDGE:
82 ret = fn(tmp,
83 PCI_DEVID(tmp->bus->number,
84 tmp->devfn), data);
85 if (ret)
86 return ret;
87 continue;
88 }
89 } else {
90 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
91 ret = fn(tmp,
92 PCI_DEVID(tmp->subordinate->number,
93 PCI_DEVFN(0, 0)), data);
94 else
95 ret = fn(tmp,
96 PCI_DEVID(tmp->bus->number,
97 tmp->devfn), data);
98 if (ret)
99 return ret;
100 }
101 }
102
103 return ret;
104}
105
106static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
107{
108 struct pci_bus *child;
109 struct pci_bus *tmp;
110
111 if (bus->number == busnr)
112 return bus;
113
114 list_for_each_entry(tmp, &bus->children, node) {
115 child = pci_do_find_bus(tmp, busnr);
116 if (child)
117 return child;
118 }
119 return NULL;
120}
121
122/**
123 * pci_find_bus - locate PCI bus from a given domain and bus number
124 * @domain: number of PCI domain to search
125 * @busnr: number of desired PCI bus
126 *
127 * Given a PCI bus number and domain number, the desired PCI bus is located
128 * in the global list of PCI buses. If the bus is found, a pointer to its
129 * data structure is returned. If no bus is found, %NULL is returned.
130 */
131struct pci_bus *pci_find_bus(int domain, int busnr)
132{
133 struct pci_bus *bus = NULL;
134 struct pci_bus *tmp_bus;
135
136 while ((bus = pci_find_next_bus(bus)) != NULL) {
137 if (pci_domain_nr(bus) != domain)
138 continue;
139 tmp_bus = pci_do_find_bus(bus, busnr);
140 if (tmp_bus)
141 return tmp_bus;
142 }
143 return NULL;
144}
145EXPORT_SYMBOL(pci_find_bus);
146
147/**
148 * pci_find_next_bus - begin or continue searching for a PCI bus
149 * @from: Previous PCI bus found, or %NULL for new search.
150 *
151 * Iterates through the list of known PCI buses. A new search is
152 * initiated by passing %NULL as the @from argument. Otherwise if
153 * @from is not %NULL, searches continue from next device on the
154 * global list.
155 */
156struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
157{
158 struct list_head *n;
159 struct pci_bus *b = NULL;
160
161 WARN_ON(in_interrupt());
162 down_read(&pci_bus_sem);
163 n = from ? from->node.next : pci_root_buses.next;
164 if (n != &pci_root_buses)
165 b = list_entry(n, struct pci_bus, node);
166 up_read(&pci_bus_sem);
167 return b;
168}
169EXPORT_SYMBOL(pci_find_next_bus);
170
171/**
172 * pci_get_slot - locate PCI device for a given PCI slot
173 * @bus: PCI bus on which desired PCI device resides
174 * @devfn: encodes number of PCI slot in which the desired PCI
175 * device resides and the logical device number within that slot
176 * in case of multi-function devices.
177 *
178 * Given a PCI bus and slot/function number, the desired PCI device
179 * is located in the list of PCI devices.
180 * If the device is found, its reference count is increased and this
181 * function returns a pointer to its data structure. The caller must
182 * decrement the reference count by calling pci_dev_put().
183 * If no device is found, %NULL is returned.
184 */
185struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
186{
187 struct pci_dev *dev;
188
189 WARN_ON(in_interrupt());
190 down_read(&pci_bus_sem);
191
192 list_for_each_entry(dev, &bus->devices, bus_list) {
193 if (dev->devfn == devfn)
194 goto out;
195 }
196
197 dev = NULL;
198 out:
199 pci_dev_get(dev);
200 up_read(&pci_bus_sem);
201 return dev;
202}
203EXPORT_SYMBOL(pci_get_slot);
204
205/**
206 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
207 * @domain: PCI domain/segment on which the PCI device resides.
208 * @bus: PCI bus on which desired PCI device resides
209 * @devfn: encodes number of PCI slot in which the desired PCI device
210 * resides and the logical device number within that slot in case of
211 * multi-function devices.
212 *
213 * Given a PCI domain, bus, and slot/function number, the desired PCI
214 * device is located in the list of PCI devices. If the device is
215 * found, its reference count is increased and this function returns a
216 * pointer to its data structure. The caller must decrement the
217 * reference count by calling pci_dev_put(). If no device is found,
218 * %NULL is returned.
219 */
220struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
221 unsigned int devfn)
222{
223 struct pci_dev *dev = NULL;
224
225 for_each_pci_dev(dev) {
226 if (pci_domain_nr(dev->bus) == domain &&
227 (dev->bus->number == bus && dev->devfn == devfn))
228 return dev;
229 }
230 return NULL;
231}
232EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
233
234static int match_pci_dev_by_id(struct device *dev, void *data)
235{
236 struct pci_dev *pdev = to_pci_dev(dev);
237 struct pci_device_id *id = data;
238
239 if (pci_match_one_device(id, pdev))
240 return 1;
241 return 0;
242}
243
244/*
245 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
246 * @id: pointer to struct pci_device_id to match for the device
247 * @from: Previous PCI device found in search, or %NULL for new search.
248 *
249 * Iterates through the list of known PCI devices. If a PCI device is found
250 * with a matching id a pointer to its device structure is returned, and the
251 * reference count to the device is incremented. Otherwise, %NULL is returned.
252 * A new search is initiated by passing %NULL as the @from argument. Otherwise
253 * if @from is not %NULL, searches continue from next device on the global
254 * list. The reference count for @from is always decremented if it is not
255 * %NULL.
256 *
257 * This is an internal function for use by the other search functions in
258 * this file.
259 */
260static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
261 struct pci_dev *from)
262{
263 struct device *dev;
264 struct device *dev_start = NULL;
265 struct pci_dev *pdev = NULL;
266
267 WARN_ON(in_interrupt());
268 if (from)
269 dev_start = &from->dev;
270 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
271 match_pci_dev_by_id);
272 if (dev)
273 pdev = to_pci_dev(dev);
274 pci_dev_put(from);
275 return pdev;
276}
277
278/**
279 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
280 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
281 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
282 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
283 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
284 * @from: Previous PCI device found in search, or %NULL for new search.
285 *
286 * Iterates through the list of known PCI devices. If a PCI device is found
287 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
288 * device structure is returned, and the reference count to the device is
289 * incremented. Otherwise, %NULL is returned. A new search is initiated by
290 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
291 * searches continue from next device on the global list.
292 * The reference count for @from is always decremented if it is not %NULL.
293 */
294struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
295 unsigned int ss_vendor, unsigned int ss_device,
296 struct pci_dev *from)
297{
298 struct pci_device_id id = {
299 .vendor = vendor,
300 .device = device,
301 .subvendor = ss_vendor,
302 .subdevice = ss_device,
303 };
304
305 return pci_get_dev_by_id(&id, from);
306}
307EXPORT_SYMBOL(pci_get_subsys);
308
309/**
310 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
311 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
312 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
313 * @from: Previous PCI device found in search, or %NULL for new search.
314 *
315 * Iterates through the list of known PCI devices. If a PCI device is
316 * found with a matching @vendor and @device, the reference count to the
317 * device is incremented and a pointer to its device structure is returned.
318 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
319 * as the @from argument. Otherwise if @from is not %NULL, searches continue
320 * from next device on the global list. The reference count for @from is
321 * always decremented if it is not %NULL.
322 */
323struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
324 struct pci_dev *from)
325{
326 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
327}
328EXPORT_SYMBOL(pci_get_device);
329
330/**
331 * pci_get_class - begin or continue searching for a PCI device by class
332 * @class: search for a PCI device with this class designation
333 * @from: Previous PCI device found in search, or %NULL for new search.
334 *
335 * Iterates through the list of known PCI devices. If a PCI device is
336 * found with a matching @class, the reference count to the device is
337 * incremented and a pointer to its device structure is returned.
338 * Otherwise, %NULL is returned.
339 * A new search is initiated by passing %NULL as the @from argument.
340 * Otherwise if @from is not %NULL, searches continue from next device
341 * on the global list. The reference count for @from is always decremented
342 * if it is not %NULL.
343 */
344struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
345{
346 struct pci_device_id id = {
347 .vendor = PCI_ANY_ID,
348 .device = PCI_ANY_ID,
349 .subvendor = PCI_ANY_ID,
350 .subdevice = PCI_ANY_ID,
351 .class_mask = PCI_ANY_ID,
352 .class = class,
353 };
354
355 return pci_get_dev_by_id(&id, from);
356}
357EXPORT_SYMBOL(pci_get_class);
358
359/**
360 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
361 * @ids: A pointer to a null terminated list of struct pci_device_id structures
362 * that describe the type of PCI device the caller is trying to find.
363 *
364 * Obvious fact: You do not have a reference to any device that might be found
365 * by this function, so if that device is removed from the system right after
366 * this function is finished, the value will be stale. Use this function to
367 * find devices that are usually built into a system, or for a general hint as
368 * to if another device happens to be present at this specific moment in time.
369 */
370int pci_dev_present(const struct pci_device_id *ids)
371{
372 struct pci_dev *found = NULL;
373
374 WARN_ON(in_interrupt());
375 while (ids->vendor || ids->subvendor || ids->class_mask) {
376 found = pci_get_dev_by_id(ids, NULL);
377 if (found) {
378 pci_dev_put(found);
379 return 1;
380 }
381 ids++;
382 }
383
384 return 0;
385}
386EXPORT_SYMBOL(pci_dev_present);