mm-only debug patch...
[mmotm.git] / drivers / pci / search.c
blobec415352d9ba5cbf0d5572adfad37618ea88d773
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/module.h>
13 #include <linux/interrupt.h>
14 #include "pci.h"
16 DECLARE_RWSEM(pci_bus_sem);
18 * find the upstream PCIE-to-PCI bridge of a PCI device
19 * if the device is PCIE, return NULL
20 * if the device isn't connected to a PCIE bridge (that is its parent is a
21 * legacy PCI bridge and the bridge is directly connected to bus 0), return its
22 * parent
24 struct pci_dev *
25 pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
27 struct pci_dev *tmp = NULL;
29 if (pdev->is_pcie)
30 return NULL;
31 while (1) {
32 if (pci_is_root_bus(pdev->bus))
33 break;
34 pdev = pdev->bus->self;
35 /* a p2p bridge */
36 if (!pdev->is_pcie) {
37 tmp = pdev;
38 continue;
40 /* PCI device should connect to a PCIE bridge */
41 if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
42 /* Busted hardware? */
43 WARN_ON_ONCE(1);
44 return NULL;
46 return pdev;
49 return tmp;
52 static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
54 struct pci_bus* child;
55 struct list_head *tmp;
57 if(bus->number == busnr)
58 return bus;
60 list_for_each(tmp, &bus->children) {
61 child = pci_do_find_bus(pci_bus_b(tmp), busnr);
62 if(child)
63 return child;
65 return NULL;
68 /**
69 * pci_find_bus - locate PCI bus from a given domain and bus number
70 * @domain: number of PCI domain to search
71 * @busnr: number of desired PCI bus
73 * Given a PCI bus number and domain number, the desired PCI bus is located
74 * in the global list of PCI buses. If the bus is found, a pointer to its
75 * data structure is returned. If no bus is found, %NULL is returned.
77 struct pci_bus * pci_find_bus(int domain, int busnr)
79 struct pci_bus *bus = NULL;
80 struct pci_bus *tmp_bus;
82 while ((bus = pci_find_next_bus(bus)) != NULL) {
83 if (pci_domain_nr(bus) != domain)
84 continue;
85 tmp_bus = pci_do_find_bus(bus, busnr);
86 if (tmp_bus)
87 return tmp_bus;
89 return NULL;
92 /**
93 * pci_find_next_bus - begin or continue searching for a PCI bus
94 * @from: Previous PCI bus found, or %NULL for new search.
96 * Iterates through the list of known PCI busses. A new search is
97 * initiated by passing %NULL as the @from argument. Otherwise if
98 * @from is not %NULL, searches continue from next device on the
99 * global list.
101 struct pci_bus *
102 pci_find_next_bus(const struct pci_bus *from)
104 struct list_head *n;
105 struct pci_bus *b = NULL;
107 WARN_ON(in_interrupt());
108 down_read(&pci_bus_sem);
109 n = from ? from->node.next : pci_root_buses.next;
110 if (n != &pci_root_buses)
111 b = pci_bus_b(n);
112 up_read(&pci_bus_sem);
113 return b;
117 * pci_get_slot - locate PCI device for a given PCI slot
118 * @bus: PCI bus on which desired PCI device resides
119 * @devfn: encodes number of PCI slot in which the desired PCI
120 * device resides and the logical device number within that slot
121 * in case of multi-function devices.
123 * Given a PCI bus and slot/function number, the desired PCI device
124 * is located in the list of PCI devices.
125 * If the device is found, its reference count is increased and this
126 * function returns a pointer to its data structure. The caller must
127 * decrement the reference count by calling pci_dev_put().
128 * If no device is found, %NULL is returned.
130 struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
132 struct list_head *tmp;
133 struct pci_dev *dev;
135 WARN_ON(in_interrupt());
136 down_read(&pci_bus_sem);
138 list_for_each(tmp, &bus->devices) {
139 dev = pci_dev_b(tmp);
140 if (dev->devfn == devfn)
141 goto out;
144 dev = NULL;
145 out:
146 pci_dev_get(dev);
147 up_read(&pci_bus_sem);
148 return dev;
152 * pci_get_bus_and_slot - locate PCI device from a given PCI bus & slot
153 * @bus: number of PCI bus on which desired PCI device resides
154 * @devfn: encodes number of PCI slot in which the desired PCI
155 * device resides and the logical device number within that slot
156 * in case of multi-function devices.
158 * Note: the bus/slot search is limited to PCI domain (segment) 0.
160 * Given a PCI bus and slot/function number, the desired PCI device
161 * is located in system global list of PCI devices. If the device
162 * is found, a pointer to its data structure is returned. If no
163 * device is found, %NULL is returned. The returned device has its
164 * reference count bumped by one.
167 struct pci_dev * pci_get_bus_and_slot(unsigned int bus, unsigned int devfn)
169 struct pci_dev *dev = NULL;
171 while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
172 if (pci_domain_nr(dev->bus) == 0 &&
173 (dev->bus->number == bus && dev->devfn == devfn))
174 return dev;
176 return NULL;
179 static int match_pci_dev_by_id(struct device *dev, void *data)
181 struct pci_dev *pdev = to_pci_dev(dev);
182 struct pci_device_id *id = data;
184 if (pci_match_one_device(id, pdev))
185 return 1;
186 return 0;
190 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
191 * @id: pointer to struct pci_device_id to match for the device
192 * @from: Previous PCI device found in search, or %NULL for new search.
194 * Iterates through the list of known PCI devices. If a PCI device is found
195 * with a matching id a pointer to its device structure is returned, and the
196 * reference count to the device is incremented. Otherwise, %NULL is returned.
197 * A new search is initiated by passing %NULL as the @from argument. Otherwise
198 * if @from is not %NULL, searches continue from next device on the global
199 * list. The reference count for @from is always decremented if it is not
200 * %NULL.
202 * This is an internal function for use by the other search functions in
203 * this file.
205 static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
206 struct pci_dev *from)
208 struct device *dev;
209 struct device *dev_start = NULL;
210 struct pci_dev *pdev = NULL;
212 WARN_ON(in_interrupt());
213 if (from)
214 dev_start = &from->dev;
215 dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
216 match_pci_dev_by_id);
217 if (dev)
218 pdev = to_pci_dev(dev);
219 if (from)
220 pci_dev_put(from);
221 return pdev;
225 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
226 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
227 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
228 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
229 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
230 * @from: Previous PCI device found in search, or %NULL for new search.
232 * Iterates through the list of known PCI devices. If a PCI device is found
233 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
234 * device structure is returned, and the reference count to the device is
235 * incremented. Otherwise, %NULL is returned. A new search is initiated by
236 * passing %NULL as the @from argument. Otherwise if @from is not %NULL,
237 * searches continue from next device on the global list.
238 * The reference count for @from is always decremented if it is not %NULL.
240 struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
241 unsigned int ss_vendor, unsigned int ss_device,
242 struct pci_dev *from)
244 struct pci_dev *pdev;
245 struct pci_device_id *id;
248 * pci_find_subsys() can be called on the ide_setup() path,
249 * super-early in boot. But the down_read() will enable local
250 * interrupts, which can cause some machines to crash. So here we
251 * detect and flag that situation and bail out early.
253 if (unlikely(no_pci_devices()))
254 return NULL;
256 id = kzalloc(sizeof(*id), GFP_KERNEL);
257 if (!id)
258 return NULL;
259 id->vendor = vendor;
260 id->device = device;
261 id->subvendor = ss_vendor;
262 id->subdevice = ss_device;
264 pdev = pci_get_dev_by_id(id, from);
265 kfree(id);
267 return pdev;
271 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
272 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
273 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
274 * @from: Previous PCI device found in search, or %NULL for new search.
276 * Iterates through the list of known PCI devices. If a PCI device is
277 * found with a matching @vendor and @device, the reference count to the
278 * device is incremented and a pointer to its device structure is returned.
279 * Otherwise, %NULL is returned. A new search is initiated by passing %NULL
280 * as the @from argument. Otherwise if @from is not %NULL, searches continue
281 * from next device on the global list. The reference count for @from is
282 * always decremented if it is not %NULL.
284 struct pci_dev *
285 pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
287 return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
291 * pci_get_class - begin or continue searching for a PCI device by class
292 * @class: search for a PCI device with this class designation
293 * @from: Previous PCI device found in search, or %NULL for new search.
295 * Iterates through the list of known PCI devices. If a PCI device is
296 * found with a matching @class, the reference count to the device is
297 * incremented and a pointer to its device structure is returned.
298 * Otherwise, %NULL is returned.
299 * A new search is initiated by passing %NULL as the @from argument.
300 * Otherwise if @from is not %NULL, searches continue from next device
301 * on the global list. The reference count for @from is always decremented
302 * if it is not %NULL.
304 struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
306 struct pci_dev *dev;
307 struct pci_device_id *id;
309 id = kzalloc(sizeof(*id), GFP_KERNEL);
310 if (!id)
311 return NULL;
312 id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
313 id->class_mask = PCI_ANY_ID;
314 id->class = class;
316 dev = pci_get_dev_by_id(id, from);
317 kfree(id);
318 return dev;
322 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
323 * @ids: A pointer to a null terminated list of struct pci_device_id structures
324 * that describe the type of PCI device the caller is trying to find.
326 * Obvious fact: You do not have a reference to any device that might be found
327 * by this function, so if that device is removed from the system right after
328 * this function is finished, the value will be stale. Use this function to
329 * find devices that are usually built into a system, or for a general hint as
330 * to if another device happens to be present at this specific moment in time.
332 int pci_dev_present(const struct pci_device_id *ids)
334 struct pci_dev *found = NULL;
336 WARN_ON(in_interrupt());
337 while (ids->vendor || ids->subvendor || ids->class_mask) {
338 found = pci_get_dev_by_id(ids, NULL);
339 if (found)
340 goto exit;
341 ids++;
343 exit:
344 if (found)
345 return 1;
346 return 0;
348 EXPORT_SYMBOL(pci_dev_present);
350 /* For boot time work */
351 EXPORT_SYMBOL(pci_find_bus);
352 EXPORT_SYMBOL(pci_find_next_bus);
353 /* For everyone */
354 EXPORT_SYMBOL(pci_get_device);
355 EXPORT_SYMBOL(pci_get_subsys);
356 EXPORT_SYMBOL(pci_get_slot);
357 EXPORT_SYMBOL(pci_get_bus_and_slot);
358 EXPORT_SYMBOL(pci_get_class);