1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * PCI searching functions
4 *
5 * Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
6 * David Mosberger-Tang
7 * Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
8 * Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
9 */
10
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
17 DECLARE_RWSEM(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 */
pci_for_each_dma_alias(struct pci_dev * pdev,int (* fn)(struct pci_dev * pdev,u16 alias,void * data),void * data)28 int 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 /*
36 * The device may have an explicit alias requester ID for DMA where the
37 * requester is on another PCI bus.
38 */
39 pdev = pci_real_dma_dev(pdev);
40
41 ret = fn(pdev, pci_dev_id(pdev), data);
42 if (ret)
43 return ret;
44
45 /*
46 * If the device is broken and uses an alias requester ID for
47 * DMA, iterate over that too.
48 */
49 if (unlikely(pdev->dma_alias_mask)) {
50 unsigned int devfn;
51
52 for_each_set_bit(devfn, pdev->dma_alias_mask, MAX_NR_DEVFNS) {
53 ret = fn(pdev, PCI_DEVID(pdev->bus->number, devfn),
54 data);
55 if (ret)
56 return ret;
57 }
58 }
59
60 for (bus = pdev->bus; !pci_is_root_bus(bus); bus = bus->parent) {
61 struct pci_dev *tmp;
62
63 /* Skip virtual buses */
64 if (!bus->self)
65 continue;
66
67 tmp = bus->self;
68
69 /* stop at bridge where translation unit is associated */
70 if (tmp->dev_flags & PCI_DEV_FLAGS_BRIDGE_XLATE_ROOT)
71 return ret;
72
73 /*
74 * PCIe-to-PCI/X bridges alias transactions from downstream
75 * devices using the subordinate bus number (PCI Express to
76 * PCI/PCI-X Bridge Spec, rev 1.0, sec 2.3). For all cases
77 * where the upstream bus is PCI/X we alias to the bridge
78 * (there are various conditions in the previous reference
79 * where the bridge may take ownership of transactions, even
80 * when the secondary interface is PCI-X).
81 */
82 if (pci_is_pcie(tmp)) {
83 switch (pci_pcie_type(tmp)) {
84 case PCI_EXP_TYPE_ROOT_PORT:
85 case PCI_EXP_TYPE_UPSTREAM:
86 case PCI_EXP_TYPE_DOWNSTREAM:
87 continue;
88 case PCI_EXP_TYPE_PCI_BRIDGE:
89 ret = fn(tmp,
90 PCI_DEVID(tmp->subordinate->number,
91 PCI_DEVFN(0, 0)), data);
92 if (ret)
93 return ret;
94 continue;
95 case PCI_EXP_TYPE_PCIE_BRIDGE:
96 ret = fn(tmp, pci_dev_id(tmp), data);
97 if (ret)
98 return ret;
99 continue;
100 }
101 } else {
102 if (tmp->dev_flags & PCI_DEV_FLAG_PCIE_BRIDGE_ALIAS)
103 ret = fn(tmp,
104 PCI_DEVID(tmp->subordinate->number,
105 PCI_DEVFN(0, 0)), data);
106 else
107 ret = fn(tmp, pci_dev_id(tmp), data);
108 if (ret)
109 return ret;
110 }
111 }
112
113 return ret;
114 }
115
pci_do_find_bus(struct pci_bus * bus,unsigned char busnr)116 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
117 {
118 struct pci_bus *child;
119 struct pci_bus *tmp;
120
121 if (bus->number == busnr)
122 return bus;
123
124 list_for_each_entry(tmp, &bus->children, node) {
125 child = pci_do_find_bus(tmp, busnr);
126 if (child)
127 return child;
128 }
129 return NULL;
130 }
131
132 /**
133 * pci_find_bus - locate PCI bus from a given domain and bus number
134 * @domain: number of PCI domain to search
135 * @busnr: number of desired PCI bus
136 *
137 * Given a PCI bus number and domain number, the desired PCI bus is located
138 * in the global list of PCI buses. If the bus is found, a pointer to its
139 * data structure is returned. If no bus is found, %NULL is returned.
140 */
pci_find_bus(int domain,int busnr)141 struct pci_bus *pci_find_bus(int domain, int busnr)
142 {
143 struct pci_bus *bus = NULL;
144 struct pci_bus *tmp_bus;
145
146 while ((bus = pci_find_next_bus(bus)) != NULL) {
147 if (pci_domain_nr(bus) != domain)
148 continue;
149 tmp_bus = pci_do_find_bus(bus, busnr);
150 if (tmp_bus)
151 return tmp_bus;
152 }
153 return NULL;
154 }
155 EXPORT_SYMBOL(pci_find_bus);
156
157 /**
158 * pci_find_next_bus - begin or continue searching for a PCI bus
159 * @from: Previous PCI bus found, or %NULL for new search.
160 *
161 * Iterates through the list of known PCI buses. A new search is
162 * initiated by passing %NULL as the @from argument. Otherwise if
163 * @from is not %NULL, searches continue from next device on the
164 * global list.
165 */
pci_find_next_bus(const struct pci_bus * from)166 struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
167 {
168 struct list_head *n;
169 struct pci_bus *b = NULL;
170
171 WARN_ON(in_interrupt());
172 down_read(&pci_bus_sem);
173 n = from ? from->node.next : pci_root_buses.next;
174 if (n != &pci_root_buses)
175 b = list_entry(n, struct pci_bus, node);
176 up_read(&pci_bus_sem);
177 return b;
178 }
179 EXPORT_SYMBOL(pci_find_next_bus);
180
181 /**
182 * pci_get_slot - locate PCI device for a given PCI slot
183 * @bus: PCI bus on which desired PCI device resides
184 * @devfn: encodes number of PCI slot in which the desired PCI
185 * device resides and the logical device number within that slot
186 * in case of multi-function devices.
187 *
188 * Given a PCI bus and slot/function number, the desired PCI device
189 * is located in the list of PCI devices.
190 * If the device is found, its reference count is increased and this
191 * function returns a pointer to its data structure. The caller must
192 * decrement the reference count by calling pci_dev_put().
193 * If no device is found, %NULL is returned.
194 */
pci_get_slot(struct pci_bus * bus,unsigned int devfn)195 struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn)
196 {
197 struct pci_dev *dev;
198
199 WARN_ON(in_interrupt());
200 down_read(&pci_bus_sem);
201
202 list_for_each_entry(dev, &bus->devices, bus_list) {
203 if (dev->devfn == devfn)
204 goto out;
205 }
206
207 dev = NULL;
208 out:
209 pci_dev_get(dev);
210 up_read(&pci_bus_sem);
211 return dev;
212 }
213 EXPORT_SYMBOL(pci_get_slot);
214
215 /**
216 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
217 * @domain: PCI domain/segment on which the PCI device resides.
218 * @bus: PCI bus on which desired PCI device resides
219 * @devfn: encodes number of PCI slot in which the desired PCI device
220 * resides and the logical device number within that slot in case of
221 * multi-function devices.
222 *
223 * Given a PCI domain, bus, and slot/function number, the desired PCI
224 * device is located in the list of PCI devices. If the device is
225 * found, its reference count is increased and this function returns a
226 * pointer to its data structure. The caller must decrement the
227 * reference count by calling pci_dev_put(). If no device is found,
228 * %NULL is returned.
229 */
pci_get_domain_bus_and_slot(int domain,unsigned int bus,unsigned int devfn)230 struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
231 unsigned int devfn)
232 {
233 struct pci_dev *dev = NULL;
234
235 for_each_pci_dev(dev) {
236 if (pci_domain_nr(dev->bus) == domain &&
237 (dev->bus->number == bus && dev->devfn == devfn))
238 return dev;
239 }
240 return NULL;
241 }
242 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
243
match_pci_dev_by_id(struct device * dev,const void * data)244 static int match_pci_dev_by_id(struct device *dev, const void *data)
245 {
246 struct pci_dev *pdev = to_pci_dev(dev);
247 const struct pci_device_id *id = data;
248
249 if (pci_match_one_device(id, pdev))
250 return 1;
251 return 0;
252 }
253
254 /*
255 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
256 * @id: pointer to struct pci_device_id to match for the device
257 * @from: Previous PCI device found in search, or %NULL for new search.
258 *
259 * Iterates through the list of known PCI devices. If a PCI device is found
260 * with a matching id a pointer to its device structure is returned, and the
261 * reference count to the device is incremented. Otherwise, %NULL is returned.
262 * A new search is initiated by passing %NULL as the @from argument. Otherwise
263 * if @from is not %NULL, searches continue from next device on the global
264 * list. The reference count for @from is always decremented if it is not
265 * %NULL.
266 *
267 * This is an internal function for use by the other search functions in
268 * this file.
269 */
pci_get_dev_by_id(const struct pci_device_id * id,struct pci_dev * from)270 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
271 struct pci_dev *from)
272 {
273 struct device *dev;
274 struct device *dev_start = NULL;
275 struct pci_dev *pdev = NULL;
276
277 WARN_ON(in_interrupt());
278 if (from)
279 dev_start = &from->dev;
280 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
281 match_pci_dev_by_id);
282 if (dev)
283 pdev = to_pci_dev(dev);
284 pci_dev_put(from);
285 return pdev;
286 }
287
288 /**
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.
295 *
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.
303 */
pci_get_subsys(unsigned int vendor,unsigned int device,unsigned int ss_vendor,unsigned int ss_device,struct pci_dev * from)304 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
305 unsigned int ss_vendor, unsigned int ss_device,
306 struct pci_dev *from)
307 {
308 struct pci_device_id id = {
309 .vendor = vendor,
310 .device = device,
311 .subvendor = ss_vendor,
312 .subdevice = ss_device,
313 };
314
315 return pci_get_dev_by_id(&id, from);
316 }
317 EXPORT_SYMBOL(pci_get_subsys);
318
319 /**
320 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
321 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
322 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
323 * @from: Previous PCI device found in search, or %NULL for new search.
324 *
325 * Iterates through the list of known PCI devices. If a PCI device is
326 * found with a matching @vendor and @device, the reference count to the
327 * device is incremented and a pointer to its device structure is returned.
328 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
329 * as the @from argument. Otherwise if @from is not %NULL, searches continue
330 * from next device on the global list. The reference count for @from is
331 * always decremented if it is not %NULL.
332 */
pci_get_device(unsigned int vendor,unsigned int device,struct pci_dev * from)333 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
334 struct pci_dev *from)
335 {
336 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
337 }
338 EXPORT_SYMBOL(pci_get_device);
339
340 /**
341 * pci_get_class - begin or continue searching for a PCI device by class
342 * @class: search for a PCI device with this class designation
343 * @from: Previous PCI device found in search, or %NULL for new search.
344 *
345 * Iterates through the list of known PCI devices. If a PCI device is
346 * found with a matching @class, the reference count to the device is
347 * incremented and a pointer to its device structure is returned.
348 * Otherwise, %NULL is returned.
349 * A new search is initiated by passing %NULL as the @from argument.
350 * Otherwise if @from is not %NULL, searches continue from next device
351 * on the global list. The reference count for @from is always decremented
352 * if it is not %NULL.
353 */
pci_get_class(unsigned int class,struct pci_dev * from)354 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
355 {
356 struct pci_device_id id = {
357 .vendor = PCI_ANY_ID,
358 .device = PCI_ANY_ID,
359 .subvendor = PCI_ANY_ID,
360 .subdevice = PCI_ANY_ID,
361 .class_mask = PCI_ANY_ID,
362 .class = class,
363 };
364
365 return pci_get_dev_by_id(&id, from);
366 }
367 EXPORT_SYMBOL(pci_get_class);
368
369 /**
370 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
371 * @ids: A pointer to a null terminated list of struct pci_device_id structures
372 * that describe the type of PCI device the caller is trying to find.
373 *
374 * Obvious fact: You do not have a reference to any device that might be found
375 * by this function, so if that device is removed from the system right after
376 * this function is finished, the value will be stale. Use this function to
377 * find devices that are usually built into a system, or for a general hint as
378 * to if another device happens to be present at this specific moment in time.
379 */
pci_dev_present(const struct pci_device_id * ids)380 int pci_dev_present(const struct pci_device_id *ids)
381 {
382 struct pci_dev *found = NULL;
383
384 WARN_ON(in_interrupt());
385 while (ids->vendor || ids->subvendor || ids->class_mask) {
386 found = pci_get_dev_by_id(ids, NULL);
387 if (found) {
388 pci_dev_put(found);
389 return 1;
390 }
391 ids++;
392 }
393
394 return 0;
395 }
396 EXPORT_SYMBOL(pci_dev_present);
397
