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
16 DECLARE_RWSEM(pci_bus_sem);
17 EXPORT_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 */
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 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
pci_do_find_bus(struct pci_bus * bus,unsigned char busnr)106 static 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 */
pci_find_bus(int domain,int busnr)131 struct 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 }
145 EXPORT_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 */
pci_find_next_bus(const struct pci_bus * from)156 struct 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 }
169 EXPORT_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 */
pci_get_slot(struct pci_bus * bus,unsigned int devfn)185 struct 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 }
203 EXPORT_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 */
pci_get_domain_bus_and_slot(int domain,unsigned int bus,unsigned int devfn)220 struct 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 }
232 EXPORT_SYMBOL(pci_get_domain_bus_and_slot);
233
match_pci_dev_by_id(struct device * dev,void * data)234 static 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 */
pci_get_dev_by_id(const struct pci_device_id * id,struct pci_dev * from)260 static 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 if (from)
275 pci_dev_put(from);
276 return pdev;
277 }
278
279 /**
280 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
281 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
282 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
283 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
284 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
285 * @from: Previous PCI device found in search, or %NULL for new search.
286 *
287 * Iterates through the list of known PCI devices. If a PCI device is found
288 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
289 * device structure is returned, and the reference count to the device is
290 * incremented. Otherwise, %NULL is returned. A new search is initiated by
291 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
292 * searches continue from next device on the global list.
293 * The reference count for @from is always decremented if it is not %NULL.
294 */
pci_get_subsys(unsigned int vendor,unsigned int device,unsigned int ss_vendor,unsigned int ss_device,struct pci_dev * from)295 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
296 unsigned int ss_vendor, unsigned int ss_device,
297 struct pci_dev *from)
298 {
299 struct pci_device_id id = {
300 .vendor = vendor,
301 .device = device,
302 .subvendor = ss_vendor,
303 .subdevice = ss_device,
304 };
305
306 return pci_get_dev_by_id(&id, from);
307 }
308 EXPORT_SYMBOL(pci_get_subsys);
309
310 /**
311 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
312 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
313 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
314 * @from: Previous PCI device found in search, or %NULL for new search.
315 *
316 * Iterates through the list of known PCI devices. If a PCI device is
317 * found with a matching @vendor and @device, the reference count to the
318 * device is incremented and a pointer to its device structure is returned.
319 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
320 * as the @from argument. Otherwise if @from is not %NULL, searches continue
321 * from next device on the global list. The reference count for @from is
322 * always decremented if it is not %NULL.
323 */
pci_get_device(unsigned int vendor,unsigned int device,struct pci_dev * from)324 struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
325 struct pci_dev *from)
326 {
327 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
328 }
329 EXPORT_SYMBOL(pci_get_device);
330
331 /**
332 * pci_get_class - begin or continue searching for a PCI device by class
333 * @class: search for a PCI device with this class designation
334 * @from: Previous PCI device found in search, or %NULL for new search.
335 *
336 * Iterates through the list of known PCI devices. If a PCI device is
337 * found with a matching @class, the reference count to the device is
338 * incremented and a pointer to its device structure is returned.
339 * Otherwise, %NULL is returned.
340 * A new search is initiated by passing %NULL as the @from argument.
341 * Otherwise if @from is not %NULL, searches continue from next device
342 * on the global list. The reference count for @from is always decremented
343 * if it is not %NULL.
344 */
pci_get_class(unsigned int class,struct pci_dev * from)345 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
346 {
347 struct pci_device_id id = {
348 .vendor = PCI_ANY_ID,
349 .device = PCI_ANY_ID,
350 .subvendor = PCI_ANY_ID,
351 .subdevice = PCI_ANY_ID,
352 .class_mask = PCI_ANY_ID,
353 .class = class,
354 };
355
356 return pci_get_dev_by_id(&id, from);
357 }
358 EXPORT_SYMBOL(pci_get_class);
359
360 /**
361 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
362 * @ids: A pointer to a null terminated list of struct pci_device_id structures
363 * that describe the type of PCI device the caller is trying to find.
364 *
365 * Obvious fact: You do not have a reference to any device that might be found
366 * by this function, so if that device is removed from the system right after
367 * this function is finished, the value will be stale. Use this function to
368 * find devices that are usually built into a system, or for a general hint as
369 * to if another device happens to be present at this specific moment in time.
370 */
pci_dev_present(const struct pci_device_id * ids)371 int pci_dev_present(const struct pci_device_id *ids)
372 {
373 struct pci_dev *found = NULL;
374
375 WARN_ON(in_interrupt());
376 while (ids->vendor || ids->subvendor || ids->class_mask) {
377 found = pci_get_dev_by_id(ids, NULL);
378 if (found) {
379 pci_dev_put(found);
380 return 1;
381 }
382 ids++;
383 }
384
385 return 0;
386 }
387 EXPORT_SYMBOL(pci_dev_present);
388