summaryrefslogtreecommitdiffstats
path: root/drivers/pci/search.c
blob: 75826482c71a5e061482af4147d84cab9930852d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
/*
 * 	PCI searching functions.
 *
 *	Copyright (C) 1993 -- 1997 Drew Eckhardt, Frederic Potter,
 *					David Mosberger-Tang
 *	Copyright (C) 1997 -- 2000 Martin Mares <mj@ucw.cz>
 *	Copyright (C) 2003 -- 2004 Greg Kroah-Hartman <greg@kroah.com>
 */

#include <linux/init.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include "pci.h"

DECLARE_RWSEM(pci_bus_sem);
/*
 * find the upstream PCIE-to-PCI bridge of a PCI device
 * if the device is PCIE, return NULL
 * if the device isn't connected to a PCIE bridge (that is its parent is a
 * legacy PCI bridge and the bridge is directly connected to bus 0), return its
 * parent
 */
struct pci_dev *
pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
{
	struct pci_dev *tmp = NULL;

	if (pdev->is_pcie)
		return NULL;
	while (1) {
		if (pci_is_root_bus(pdev->bus))
			break;
		pdev = pdev->bus->self;
		/* a p2p bridge */
		if (!pdev->is_pcie) {
			tmp = pdev;
			continue;
		}
		/* PCI device should connect to a PCIE bridge */
		if (pdev->pcie_type != PCI_EXP_TYPE_PCI_BRIDGE) {
			/* Busted hardware? */
			WARN_ON_ONCE(1);
			return NULL;
		}
		return pdev;
	}

	return tmp;
}

static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
{
	struct pci_bus* child;
	struct list_head *tmp;

	if(bus->number == busnr)
		return bus;

	list_for_each(tmp, &bus->children) {
		child = pci_do_find_bus(pci_bus_b(tmp), busnr);
		if(child)
			return child;
	}
	return NULL;
}

/**
 * pci_find_bus - locate PCI bus from a given domain and bus number
 * @domain: number of PCI domain to search
 * @busnr: number of desired PCI bus
 *
 * Given a PCI bus number and domain number, the desired PCI bus is located
 * in the global list of PCI buses.  If the bus is found, a pointer to its
 * data structure is returned.  If no bus is found, %NULL is returned.
 */
struct pci_bus * pci_find_bus(int domain, int busnr)
{
	struct pci_bus *bus = NULL;
	struct pci_bus *tmp_bus;

	while ((bus = pci_find_next_bus(bus)) != NULL)  {
		if (pci_domain_nr(bus) != domain)
			continue;
		tmp_bus = pci_do_find_bus(bus, busnr);
		if (tmp_bus)
			return tmp_bus;
	}
	return NULL;
}

/**
 * pci_find_next_bus - begin or continue searching for a PCI bus
 * @from: Previous PCI bus found, or %NULL for new search.
 *
 * Iterates through the list of known PCI busses.  A new search is
 * initiated by passing %NULL as the @from argument.  Otherwise if
 * @from is not %NULL, searches continue from next device on the
 * global list.
 */
struct pci_bus * 
pci_find_next_bus(const struct pci_bus *from)
{
	struct list_head *n;
	struct pci_bus *b = NULL;

	WARN_ON(in_interrupt());
	down_read(&pci_bus_sem);
	n = from ? from->node.next : pci_root_buses.next;
	if (n != &pci_root_buses)
		b = pci_bus_b(n);
	up_read(&pci_bus_sem);
	return b;
}

/**
 * pci_get_slot - locate PCI device for a given PCI slot
 * @bus: PCI bus on which desired PCI device resides
 * @devfn: encodes number of PCI slot in which the desired PCI 
 * device resides and the logical device number within that slot 
 * in case of multi-function devices.
 *
 * Given a PCI bus and slot/function number, the desired PCI device 
 * is located in the list of PCI devices.
 * If the device is found, its reference count is increased and this
 * function returns a pointer to its data structure.  The caller must
 * decrement the reference count by calling pci_dev_put().
 * If no device is found, %NULL is returned.
 */
struct pci_dev * pci_get_slot(struct pci_bus *bus, unsigned int devfn)
{
	struct list_head *tmp;
	struct pci_dev *dev;

	WARN_ON(in_interrupt());
	down_read(&pci_bus_sem);

	list_for_each(tmp, &bus->devices) {
		dev = pci_dev_b(tmp);
		if (dev->devfn == devfn)
			goto out;
	}

	dev = NULL;
 out:
	pci_dev_get(dev);
	up_read(&pci_bus_sem);
	return dev;
}

/**
 * pci_get_domain_bus_and_slot - locate PCI device for a given PCI domain (segment), bus, and slot
 * @domain: PCI domain/segment on which the PCI device resides.
 * @bus: PCI bus on which desired PCI device resides
 * @devfn: encodes number of PCI slot in which the desired PCI device
 * resides and the logical device number within that slot in case of
 * multi-function devices.
 *
 * Given a PCI domain, bus, and slot/function number, the desired PCI
 * device is located in the list of PCI devices. If the device is
 * found, its reference count is increased and this function returns a
 * pointer to its data structure.  The caller must decrement the
 * reference count by calling pci_dev_put().  If no device is found,
 * %NULL is returned.
 */
struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus,
					    unsigned int devfn)
{
	struct pci_dev *dev = NULL;

	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
		if (pci_domain_nr(dev->bus) == domain &&
		    (dev->bus->number == bus && dev->devfn == devfn))
			return dev;
	}
	return NULL;
}
EXPORT_SYMBOL(pci_get_domain_bus_and_slot);

static int match_pci_dev_by_id(struct device *dev, void *data)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	struct pci_device_id *id = data;

	if (pci_match_one_device(id, pdev))
		return 1;
	return 0;
}

/*
 * pci_get_dev_by_id - begin or continue searching for a PCI device by id
 * @id: pointer to struct pci_device_id to match for the device
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is found
 * with a matching id a pointer to its device structure is returned, and the
 * reference count to the device is incremented.  Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL as the @from argument.  Otherwise
 * if @from is not %NULL, searches continue from next device on the global
 * list.  The reference count for @from is always decremented if it is not
 * %NULL.
 *
 * This is an internal function for use by the other search functions in
 * this file.
 */
static struct pci_dev *pci_get_dev_by_id(const struct pci_device_id *id,
					 struct pci_dev *from)
{
	struct device *dev;
	struct device *dev_start = NULL;
	struct pci_dev *pdev = NULL;

	WARN_ON(in_interrupt());
	if (from)
		dev_start = &from->dev;
	dev = bus_find_device(&pci_bus_type, dev_start, (void *)id,
			      match_pci_dev_by_id);
	if (dev)
		pdev = to_pci_dev(dev);
	if (from)
		pci_dev_put(from);
	return pdev;
}

/**
 * pci_get_subsys - begin or continue searching for a PCI device by vendor/subvendor/device/subdevice id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @ss_vendor: PCI subsystem vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @ss_device: PCI subsystem device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is found
 * with a matching @vendor, @device, @ss_vendor and @ss_device, a pointer to its
 * device structure is returned, and the reference count to the device is
 * incremented.  Otherwise, %NULL is returned.  A new search is initiated by
 * passing %NULL as the @from argument.  Otherwise if @from is not %NULL,
 * searches continue from next device on the global list.
 * The reference count for @from is always decremented if it is not %NULL.
 */
struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
			       unsigned int ss_vendor, unsigned int ss_device,
			       struct pci_dev *from)
{
	struct pci_dev *pdev;
	struct pci_device_id *id;

	/*
	 * pci_find_subsys() can be called on the ide_setup() path,
	 * super-early in boot.  But the down_read() will enable local
	 * interrupts, which can cause some machines to crash.  So here we
	 * detect and flag that situation and bail out early.
	 */
	if (unlikely(no_pci_devices()))
		return NULL;

	id = kzalloc(sizeof(*id), GFP_KERNEL);
	if (!id)
		return NULL;
	id->vendor = vendor;
	id->device = device;
	id->subvendor = ss_vendor;
	id->subdevice = ss_device;

	pdev = pci_get_dev_by_id(id, from);
	kfree(id);

	return pdev;
}

/**
 * pci_get_device - begin or continue searching for a PCI device by vendor/device id
 * @vendor: PCI vendor id to match, or %PCI_ANY_ID to match all vendor ids
 * @device: PCI device id to match, or %PCI_ANY_ID to match all device ids
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @vendor and @device, the reference count to the
 * device is incremented and a pointer to its device structure is returned.
 * Otherwise, %NULL is returned.  A new search is initiated by passing %NULL
 * as the @from argument.  Otherwise if @from is not %NULL, searches continue
 * from next device on the global list.  The reference count for @from is
 * always decremented if it is not %NULL.
 */
struct pci_dev *
pci_get_device(unsigned int vendor, unsigned int device, struct pci_dev *from)
{
	return pci_get_subsys(vendor, device, PCI_ANY_ID, PCI_ANY_ID, from);
}

/**
 * pci_get_class - begin or continue searching for a PCI device by class
 * @class: search for a PCI device with this class designation
 * @from: Previous PCI device found in search, or %NULL for new search.
 *
 * Iterates through the list of known PCI devices.  If a PCI device is
 * found with a matching @class, the reference count to the device is
 * incremented and a pointer to its device structure is returned.
 * Otherwise, %NULL is returned.
 * A new search is initiated by passing %NULL as the @from argument.
 * Otherwise if @from is not %NULL, searches continue from next device
 * on the global list.  The reference count for @from is always decremented
 * if it is not %NULL.
 */
struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
{
	struct pci_dev *dev;
	struct pci_device_id *id;

	id = kzalloc(sizeof(*id), GFP_KERNEL);
	if (!id)
		return NULL;
	id->vendor = id->device = id->subvendor = id->subdevice = PCI_ANY_ID;
	id->class_mask = PCI_ANY_ID;
	id->class = class;

	dev = pci_get_dev_by_id(id, from);
	kfree(id);
	return dev;
}

/**
 * pci_dev_present - Returns 1 if device matching the device list is present, 0 if not.
 * @ids: A pointer to a null terminated list of struct pci_device_id structures
 * that describe the type of PCI device the caller is trying to find.
 *
 * Obvious fact: You do not have a reference to any device that might be found
 * by this function, so if that device is removed from the system right after
 * this function is finished, the value will be stale.  Use this function to
 * find devices that are usually built into a system, or for a general hint as
 * to if another device happens to be present at this specific moment in time.
 */
int pci_dev_present(const struct pci_device_id *ids)
{
	struct pci_dev *found = NULL;

	WARN_ON(in_interrupt());
	while (ids->vendor || ids->subvendor || ids->class_mask) {
		found = pci_get_dev_by_id(ids, NULL);
		if (found)
			goto exit;
		ids++;
	}
exit:
	if (found)
		return 1;
	return 0;
}
EXPORT_SYMBOL(pci_dev_present);

/* For boot time work */
EXPORT_SYMBOL(pci_find_bus);
EXPORT_SYMBOL(pci_find_next_bus);
/* For everyone */
EXPORT_SYMBOL(pci_get_device);
EXPORT_SYMBOL(pci_get_subsys);
EXPORT_SYMBOL(pci_get_slot);
EXPORT_SYMBOL(pci_get_class);