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 | */ |
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(dev: pdev); |
40 | |
41 | ret = fn(pdev, pci_dev_id(dev: 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(pbus: 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(dev: tmp)) { |
83 | switch (pci_pcie_type(dev: 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(dev: 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(dev: tmp), data); |
108 | if (ret) |
109 | return ret; |
110 | } |
111 | } |
112 | |
113 | return ret; |
114 | } |
115 | |
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(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 | */ |
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(from: 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 | */ |
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 | down_read(sem: &pci_bus_sem); |
172 | n = from ? from->node.next : pci_root_buses.next; |
173 | if (n != &pci_root_buses) |
174 | b = list_entry(n, struct pci_bus, node); |
175 | up_read(sem: &pci_bus_sem); |
176 | return b; |
177 | } |
178 | EXPORT_SYMBOL(pci_find_next_bus); |
179 | |
180 | /** |
181 | * pci_get_slot - locate PCI device for a given PCI slot |
182 | * @bus: PCI bus on which desired PCI device resides |
183 | * @devfn: encodes number of PCI slot in which the desired PCI |
184 | * device resides and the logical device number within that slot |
185 | * in case of multi-function devices. |
186 | * |
187 | * Given a PCI bus and slot/function number, the desired PCI device |
188 | * is located in the list of PCI devices. |
189 | * If the device is found, its reference count is increased and this |
190 | * function returns a pointer to its data structure. The caller must |
191 | * decrement the reference count by calling pci_dev_put(). |
192 | * If no device is found, %NULL is returned. |
193 | */ |
194 | struct pci_dev *pci_get_slot(struct pci_bus *bus, unsigned int devfn) |
195 | { |
196 | struct pci_dev *dev; |
197 | |
198 | down_read(sem: &pci_bus_sem); |
199 | |
200 | list_for_each_entry(dev, &bus->devices, bus_list) { |
201 | if (dev->devfn == devfn) |
202 | goto out; |
203 | } |
204 | |
205 | dev = NULL; |
206 | out: |
207 | pci_dev_get(dev); |
208 | up_read(sem: &pci_bus_sem); |
209 | return dev; |
210 | } |
211 | EXPORT_SYMBOL(pci_get_slot); |
212 | |
213 | /** |
214 | * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot |
215 | * @domain: PCI domain/segment on which the PCI device resides. |
216 | * @bus: PCI bus on which desired PCI device resides |
217 | * @devfn: encodes number of PCI slot in which the desired PCI device |
218 | * resides and the logical device number within that slot in case of |
219 | * multi-function devices. |
220 | * |
221 | * Given a PCI domain, bus, and slot/function number, the desired PCI |
222 | * device is located in the list of PCI devices. If the device is |
223 | * found, its reference count is increased and this function returns a |
224 | * pointer to its data structure. The caller must decrement the |
225 | * reference count by calling pci_dev_put(). If no device is found, |
226 | * %NULL is returned. |
227 | */ |
228 | struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus, |
229 | unsigned int devfn) |
230 | { |
231 | struct pci_dev *dev = NULL; |
232 | |
233 | for_each_pci_dev(dev) { |
234 | if (pci_domain_nr(bus: dev->bus) == domain && |
235 | (dev->bus->number == bus && dev->devfn == devfn)) |
236 | return dev; |
237 | } |
238 | return NULL; |
239 | } |
240 | EXPORT_SYMBOL(pci_get_domain_bus_and_slot); |
241 | |
242 | static int match_pci_dev_by_id(struct device *dev, const void *data) |
243 | { |
244 | struct pci_dev *pdev = to_pci_dev(dev); |
245 | const struct pci_device_id *id = data; |
246 | |
247 | if (pci_match_one_device(id, dev: pdev)) |
248 | return 1; |
249 | return 0; |
250 | } |
251 | |
252 | /* |
253 | * pci_get_dev_by_id - begin or continue searching for a PCI device by id |
254 | * @id: pointer to struct pci_device_id to match for the device |
255 | * @from: Previous PCI device found in search, or %NULL for new search. |
256 | * |
257 | * Iterates through the list of known PCI devices. If a PCI device is found |
258 | * with a matching id a pointer to its device structure is returned, and the |
259 | * reference count to the device is incremented. Otherwise, %NULL is returned. |
260 | * A new search is initiated by passing %NULL as the @from argument. Otherwise |
261 | * if @from is not %NULL, searches continue from next device on the global |
262 | * list. The reference count for @from is always decremented if it is not |
263 | * %NULL. |
264 | * |
265 | * This is an internal function for use by the other search functions in |
266 | * this file. |
267 | */ |
268 | static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id, |
269 | struct pci_dev *from) |
270 | { |
271 | struct device *dev; |
272 | struct device *dev_start = NULL; |
273 | struct pci_dev *pdev = NULL; |
274 | |
275 | if (from) |
276 | dev_start = &from->dev; |
277 | dev = bus_find_device(bus: &pci_bus_type, start: dev_start, data: (void *)id, |
278 | match: match_pci_dev_by_id); |
279 | if (dev) |
280 | pdev = to_pci_dev(dev); |
281 | pci_dev_put(dev: from); |
282 | return pdev; |
283 | } |
284 | |
285 | /** |
286 | * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id |
287 | * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids |
288 | * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids |
289 | * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids |
290 | * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids |
291 | * @from: Previous PCI device found in search, or %NULL for new search. |
292 | * |
293 | * Iterates through the list of known PCI devices. If a PCI device is found |
294 | * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its |
295 | * device structure is returned, and the reference count to the device is |
296 | * incremented. Otherwise, %NULL is returned. A new search is initiated by |
297 | * passing %NULL as the @from argument. Otherwise if @from is not %NULL, |
298 | * searches continue from next device on the global list. |
299 | * The reference count for @from is always decremented if it is not %NULL. |
300 | */ |
301 | struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device, |
302 | unsigned int ss_vendor, unsigned int ss_device, |
303 | struct pci_dev *from) |
304 | { |
305 | struct pci_device_id id = { |
306 | .vendor = vendor, |
307 | .device = device, |
308 | .subvendor = ss_vendor, |
309 | .subdevice = ss_device, |
310 | }; |
311 | |
312 | return pci_get_dev_by_id(id: &id, from); |
313 | } |
314 | EXPORT_SYMBOL(pci_get_subsys); |
315 | |
316 | /** |
317 | * pci_get_device - begin or continue searching for a PCI device by vendor/device id |
318 | * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids |
319 | * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids |
320 | * @from: Previous PCI device found in search, or %NULL for new search. |
321 | * |
322 | * Iterates through the list of known PCI devices. If a PCI device is |
323 | * found with a matching @vendor and @device, the reference count to the |
324 | * device is incremented and a pointer to its device structure is returned. |
325 | * Otherwise, %NULL is returned. A new search is initiated by passing %NULL |
326 | * as the @from argument. Otherwise if @from is not %NULL, searches continue |
327 | * from next device on the global list. The reference count for @from is |
328 | * always decremented if it is not %NULL. |
329 | */ |
330 | struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device, |
331 | struct pci_dev *from) |
332 | { |
333 | return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from); |
334 | } |
335 | EXPORT_SYMBOL(pci_get_device); |
336 | |
337 | /** |
338 | * pci_get_class - begin or continue searching for a PCI device by class |
339 | * @class: search for a PCI device with this class designation |
340 | * @from: Previous PCI device found in search, or %NULL for new search. |
341 | * |
342 | * Iterates through the list of known PCI devices. If a PCI device is |
343 | * found with a matching @class, the reference count to the device is |
344 | * incremented and a pointer to its device structure is returned. |
345 | * Otherwise, %NULL is returned. |
346 | * A new search is initiated by passing %NULL as the @from argument. |
347 | * Otherwise if @from is not %NULL, searches continue from next device |
348 | * on the global list. The reference count for @from is always decremented |
349 | * if it is not %NULL. |
350 | */ |
351 | struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from) |
352 | { |
353 | struct pci_device_id id = { |
354 | .vendor = PCI_ANY_ID, |
355 | .device = PCI_ANY_ID, |
356 | .subvendor = PCI_ANY_ID, |
357 | .subdevice = PCI_ANY_ID, |
358 | .class_mask = PCI_ANY_ID, |
359 | .class = class, |
360 | }; |
361 | |
362 | return pci_get_dev_by_id(id: &id, from); |
363 | } |
364 | EXPORT_SYMBOL(pci_get_class); |
365 | |
366 | /** |
367 | * pci_get_base_class - searching for a PCI device by matching against the base class code only |
368 | * @class: search for a PCI device with this base class code |
369 | * @from: Previous PCI device found in search, or %NULL for new search. |
370 | * |
371 | * Iterates through the list of known PCI devices. If a PCI device is found |
372 | * with a matching base class code, the reference count to the device is |
373 | * incremented. See pci_match_one_device() to figure out how does this works. |
374 | * A new search is initiated by passing %NULL as the @from argument. |
375 | * Otherwise if @from is not %NULL, searches continue from next device on the |
376 | * global list. The reference count for @from is always decremented if it is |
377 | * not %NULL. |
378 | * |
379 | * Returns: |
380 | * A pointer to a matched PCI device, %NULL Otherwise. |
381 | */ |
382 | struct pci_dev *pci_get_base_class(unsigned int class, struct pci_dev *from) |
383 | { |
384 | struct pci_device_id id = { |
385 | .vendor = PCI_ANY_ID, |
386 | .device = PCI_ANY_ID, |
387 | .subvendor = PCI_ANY_ID, |
388 | .subdevice = PCI_ANY_ID, |
389 | .class_mask = 0xFF0000, |
390 | .class = class << 16, |
391 | }; |
392 | |
393 | return pci_get_dev_by_id(id: &id, from); |
394 | } |
395 | EXPORT_SYMBOL(pci_get_base_class); |
396 | |
397 | /** |
398 | * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not. |
399 | * @ids: A pointer to a null terminated list of struct pci_device_id structures |
400 | * that describe the type of PCI device the caller is trying to find. |
401 | * |
402 | * Obvious fact: You do not have a reference to any device that might be found |
403 | * by this function, so if that device is removed from the system right after |
404 | * this function is finished, the value will be stale. Use this function to |
405 | * find devices that are usually built into a system, or for a general hint as |
406 | * to if another device happens to be present at this specific moment in time. |
407 | */ |
408 | int pci_dev_present(const struct pci_device_id *ids) |
409 | { |
410 | struct pci_dev *found = NULL; |
411 | |
412 | while (ids->vendor || ids->subvendor || ids->class_mask) { |
413 | found = pci_get_dev_by_id(id: ids, NULL); |
414 | if (found) { |
415 | pci_dev_put(dev: found); |
416 | return 1; |
417 | } |
418 | ids++; |
419 | } |
420 | |
421 | return 0; |
422 | } |
423 | EXPORT_SYMBOL(pci_dev_present); |
424 | |