summaryrefslogtreecommitdiff
path: root/drivers/pci/pci-driver.c
blob: 98af9ecd4a90c728ebebabd6bcd96a581e06b657 (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
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
// SPDX-License-Identifier: GPL-2.0
/*
 * (C) Copyright 2002-2004, 2007 Greg Kroah-Hartman <greg@kroah.com>
 * (C) Copyright 2007 Novell Inc.
 */

#include <linux/pci.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/mempolicy.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/cpu.h>
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
#include <linux/kexec.h>
#include <linux/of_device.h>
#include <linux/acpi.h>
#include "pci.h"
#include "pcie/portdrv.h"

struct pci_dynid {
	struct list_head node;
	struct pci_device_id id;
};

/**
 * pci_add_dynid - add a new PCI device ID to this driver and re-probe devices
 * @drv: target pci driver
 * @vendor: PCI vendor ID
 * @device: PCI device ID
 * @subvendor: PCI subvendor ID
 * @subdevice: PCI subdevice ID
 * @class: PCI class
 * @class_mask: PCI class mask
 * @driver_data: private driver data
 *
 * Adds a new dynamic pci device ID to this driver and causes the
 * driver to probe for all devices again.  @drv must have been
 * registered prior to calling this function.
 *
 * CONTEXT:
 * Does GFP_KERNEL allocation.
 *
 * RETURNS:
 * 0 on success, -errno on failure.
 */
int pci_add_dynid(struct pci_driver *drv,
		  unsigned int vendor, unsigned int device,
		  unsigned int subvendor, unsigned int subdevice,
		  unsigned int class, unsigned int class_mask,
		  unsigned long driver_data)
{
	struct pci_dynid *dynid;

	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
	if (!dynid)
		return -ENOMEM;

	dynid->id.vendor = vendor;
	dynid->id.device = device;
	dynid->id.subvendor = subvendor;
	dynid->id.subdevice = subdevice;
	dynid->id.class = class;
	dynid->id.class_mask = class_mask;
	dynid->id.driver_data = driver_data;

	spin_lock(&drv->dynids.lock);
	list_add_tail(&dynid->node, &drv->dynids.list);
	spin_unlock(&drv->dynids.lock);

	return driver_attach(&drv->driver);
}
EXPORT_SYMBOL_GPL(pci_add_dynid);

static void pci_free_dynids(struct pci_driver *drv)
{
	struct pci_dynid *dynid, *n;

	spin_lock(&drv->dynids.lock);
	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
		list_del(&dynid->node);
		kfree(dynid);
	}
	spin_unlock(&drv->dynids.lock);
}

/**
 * store_new_id - sysfs frontend to pci_add_dynid()
 * @driver: target device driver
 * @buf: buffer for scanning device ID data
 * @count: input size
 *
 * Allow PCI IDs to be added to an existing driver via sysfs.
 */
static ssize_t new_id_store(struct device_driver *driver, const char *buf,
			    size_t count)
{
	struct pci_driver *pdrv = to_pci_driver(driver);
	const struct pci_device_id *ids = pdrv->id_table;
	u32 vendor, device, subvendor = PCI_ANY_ID,
		subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
	unsigned long driver_data = 0;
	int fields = 0;
	int retval = 0;

	fields = sscanf(buf, "%x %x %x %x %x %x %lx",
			&vendor, &device, &subvendor, &subdevice,
			&class, &class_mask, &driver_data);
	if (fields < 2)
		return -EINVAL;

	if (fields != 7) {
		struct pci_dev *pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
		if (!pdev)
			return -ENOMEM;

		pdev->vendor = vendor;
		pdev->device = device;
		pdev->subsystem_vendor = subvendor;
		pdev->subsystem_device = subdevice;
		pdev->class = class;

		if (pci_match_id(pdrv->id_table, pdev))
			retval = -EEXIST;

		kfree(pdev);

		if (retval)
			return retval;
	}

	/* Only accept driver_data values that match an existing id_table
	   entry */
	if (ids) {
		retval = -EINVAL;
		while (ids->vendor || ids->subvendor || ids->class_mask) {
			if (driver_data == ids->driver_data) {
				retval = 0;
				break;
			}
			ids++;
		}
		if (retval)	/* No match */
			return retval;
	}

	retval = pci_add_dynid(pdrv, vendor, device, subvendor, subdevice,
			       class, class_mask, driver_data);
	if (retval)
		return retval;
	return count;
}
static DRIVER_ATTR_WO(new_id);

/**
 * store_remove_id - remove a PCI device ID from this driver
 * @driver: target device driver
 * @buf: buffer for scanning device ID data
 * @count: input size
 *
 * Removes a dynamic pci device ID to this driver.
 */
static ssize_t remove_id_store(struct device_driver *driver, const char *buf,
			       size_t count)
{
	struct pci_dynid *dynid, *n;
	struct pci_driver *pdrv = to_pci_driver(driver);
	u32 vendor, device, subvendor = PCI_ANY_ID,
		subdevice = PCI_ANY_ID, class = 0, class_mask = 0;
	int fields = 0;
	size_t retval = -ENODEV;

	fields = sscanf(buf, "%x %x %x %x %x %x",
			&vendor, &device, &subvendor, &subdevice,
			&class, &class_mask);
	if (fields < 2)
		return -EINVAL;

	spin_lock(&pdrv->dynids.lock);
	list_for_each_entry_safe(dynid, n, &pdrv->dynids.list, node) {
		struct pci_device_id *id = &dynid->id;
		if ((id->vendor == vendor) &&
		    (id->device == device) &&
		    (subvendor == PCI_ANY_ID || id->subvendor == subvendor) &&
		    (subdevice == PCI_ANY_ID || id->subdevice == subdevice) &&
		    !((id->class ^ class) & class_mask)) {
			list_del(&dynid->node);
			kfree(dynid);
			retval = count;
			break;
		}
	}
	spin_unlock(&pdrv->dynids.lock);

	return retval;
}
static DRIVER_ATTR_WO(remove_id);

static struct attribute *pci_drv_attrs[] = {
	&driver_attr_new_id.attr,
	&driver_attr_remove_id.attr,
	NULL,
};
ATTRIBUTE_GROUPS(pci_drv);

/**
 * pci_match_id - See if a pci device matches a given pci_id table
 * @ids: array of PCI device id structures to search in
 * @dev: the PCI device structure to match against.
 *
 * Used by a driver to check whether a PCI device present in the
 * system is in its list of supported devices.  Returns the matching
 * pci_device_id structure or %NULL if there is no match.
 *
 * Deprecated, don't use this as it will not catch any dynamic ids
 * that a driver might want to check for.
 */
const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
					 struct pci_dev *dev)
{
	if (ids) {
		while (ids->vendor || ids->subvendor || ids->class_mask) {
			if (pci_match_one_device(ids, dev))
				return ids;
			ids++;
		}
	}
	return NULL;
}
EXPORT_SYMBOL(pci_match_id);

static const struct pci_device_id pci_device_id_any = {
	.vendor = PCI_ANY_ID,
	.device = PCI_ANY_ID,
	.subvendor = PCI_ANY_ID,
	.subdevice = PCI_ANY_ID,
};

/**
 * pci_match_device - Tell if a PCI device structure has a matching PCI device id structure
 * @drv: the PCI driver to match against
 * @dev: the PCI device structure to match against
 *
 * Used by a driver to check whether a PCI device present in the
 * system is in its list of supported devices.  Returns the matching
 * pci_device_id structure or %NULL if there is no match.
 */
static const struct pci_device_id *pci_match_device(struct pci_driver *drv,
						    struct pci_dev *dev)
{
	struct pci_dynid *dynid;
	const struct pci_device_id *found_id = NULL;

	/* When driver_override is set, only bind to the matching driver */
	if (dev->driver_override && strcmp(dev->driver_override, drv->name))
		return NULL;

	/* Look at the dynamic ids first, before the static ones */
	spin_lock(&drv->dynids.lock);
	list_for_each_entry(dynid, &drv->dynids.list, node) {
		if (pci_match_one_device(&dynid->id, dev)) {
			found_id = &dynid->id;
			break;
		}
	}
	spin_unlock(&drv->dynids.lock);

	if (!found_id)
		found_id = pci_match_id(drv->id_table, dev);

	/* driver_override will always match, send a dummy id */
	if (!found_id && dev->driver_override)
		found_id = &pci_device_id_any;

	return found_id;
}

struct drv_dev_and_id {
	struct pci_driver *drv;
	struct pci_dev *dev;
	const struct pci_device_id *id;
};

static long local_pci_probe(void *_ddi)
{
	struct drv_dev_and_id *ddi = _ddi;
	struct pci_dev *pci_dev = ddi->dev;
	struct pci_driver *pci_drv = ddi->drv;
	struct device *dev = &pci_dev->dev;
	int rc;

	/*
	 * Unbound PCI devices are always put in D0, regardless of
	 * runtime PM status.  During probe, the device is set to
	 * active and the usage count is incremented.  If the driver
	 * supports runtime PM, it should call pm_runtime_put_noidle(),
	 * or any other runtime PM helper function decrementing the usage
	 * count, in its probe routine and pm_runtime_get_noresume() in
	 * its remove routine.
	 */
	pm_runtime_get_sync(dev);
	pci_dev->driver = pci_drv;
	rc = pci_drv->probe(pci_dev, ddi->id);
	if (!rc)
		return rc;
	if (rc < 0) {
		pci_dev->driver = NULL;
		pm_runtime_put_sync(dev);
		return rc;
	}
	/*
	 * Probe function should return < 0 for failure, 0 for success
	 * Treat values > 0 as success, but warn.
	 */
	dev_warn(dev, "Driver probe function unexpectedly returned %d\n", rc);
	return 0;
}

static bool pci_physfn_is_probed(struct pci_dev *dev)
{
#ifdef CONFIG_PCI_IOV
	return dev->is_virtfn && dev->physfn->is_probed;
#else
	return false;
#endif
}

static int pci_call_probe(struct pci_driver *drv, struct pci_dev *dev,
			  const struct pci_device_id *id)
{
	int error, node, cpu;
	struct drv_dev_and_id ddi = { drv, dev, id };

	/*
	 * Execute driver initialization on node where the device is
	 * attached.  This way the driver likely allocates its local memory
	 * on the right node.
	 */
	node = dev_to_node(&dev->dev);
	dev->is_probed = 1;

	cpu_hotplug_disable();

	/*
	 * Prevent nesting work_on_cpu() for the case where a Virtual Function
	 * device is probed from work_on_cpu() of the Physical device.
	 */
	if (node < 0 || node >= MAX_NUMNODES || !node_online(node) ||
	    pci_physfn_is_probed(dev))
		cpu = nr_cpu_ids;
	else
		cpu = cpumask_any_and(cpumask_of_node(node), cpu_online_mask);

	if (cpu < nr_cpu_ids)
		error = work_on_cpu(cpu, local_pci_probe, &ddi);
	else
		error = local_pci_probe(&ddi);

	dev->is_probed = 0;
	cpu_hotplug_enable();
	return error;
}

/**
 * __pci_device_probe - check if a driver wants to claim a specific PCI device
 * @drv: driver to call to check if it wants the PCI device
 * @pci_dev: PCI device being probed
 *
 * returns 0 on success, else error.
 * side-effect: pci_dev->driver is set to drv when drv claims pci_dev.
 */
static int __pci_device_probe(struct pci_driver *drv, struct pci_dev *pci_dev)
{
	const struct pci_device_id *id;
	int error = 0;

	if (!pci_dev->driver && drv->probe) {
		error = -ENODEV;

		id = pci_match_device(drv, pci_dev);
		if (id)
			error = pci_call_probe(drv, pci_dev, id);
	}
	return error;
}

int __weak pcibios_alloc_irq(struct pci_dev *dev)
{
	return 0;
}

void __weak pcibios_free_irq(struct pci_dev *dev)
{
}

#ifdef CONFIG_PCI_IOV
static inline bool pci_device_can_probe(struct pci_dev *pdev)
{
	return (!pdev->is_virtfn || pdev->physfn->sriov->drivers_autoprobe);
}
#else
static inline bool pci_device_can_probe(struct pci_dev *pdev)
{
	return true;
}
#endif

static int pci_device_probe(struct device *dev)
{
	int error;
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = to_pci_driver(dev->driver);

	pci_assign_irq(pci_dev);

	error = pcibios_alloc_irq(pci_dev);
	if (error < 0)
		return error;

	pci_dev_get(pci_dev);
	if (pci_device_can_probe(pci_dev)) {
		error = __pci_device_probe(drv, pci_dev);
		if (error) {
			pcibios_free_irq(pci_dev);
			pci_dev_put(pci_dev);
		}
	}

	return error;
}

static int pci_device_remove(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	if (drv) {
		if (drv->remove) {
			pm_runtime_get_sync(dev);
			drv->remove(pci_dev);
			pm_runtime_put_noidle(dev);
		}
		pcibios_free_irq(pci_dev);
		pci_dev->driver = NULL;
		pci_iov_remove(pci_dev);
	}

	/* Undo the runtime PM settings in local_pci_probe() */
	pm_runtime_put_sync(dev);

	/*
	 * If the device is still on, set the power state as "unknown",
	 * since it might change by the next time we load the driver.
	 */
	if (pci_dev->current_state == PCI_D0)
		pci_dev->current_state = PCI_UNKNOWN;

	/*
	 * We would love to complain here if pci_dev->is_enabled is set, that
	 * the driver should have called pci_disable_device(), but the
	 * unfortunate fact is there are too many odd BIOS and bridge setups
	 * that don't like drivers doing that all of the time.
	 * Oh well, we can dream of sane hardware when we sleep, no matter how
	 * horrible the crap we have to deal with is when we are awake...
	 */

	pci_dev_put(pci_dev);
	return 0;
}

static void pci_device_shutdown(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	pm_runtime_resume(dev);

	if (drv && drv->shutdown)
		drv->shutdown(pci_dev);

	/*
	 * If this is a kexec reboot, turn off Bus Master bit on the
	 * device to tell it to not continue to do DMA. Don't touch
	 * devices in D3cold or unknown states.
	 * If it is not a kexec reboot, firmware will hit the PCI
	 * devices with big hammer and stop their DMA any way.
	 */
	if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
		pci_clear_master(pci_dev);
}

#ifdef CONFIG_PM

/* Auxiliary functions used for system resume and run-time resume. */

/**
 * pci_restore_standard_config - restore standard config registers of PCI device
 * @pci_dev: PCI device to handle
 */
static int pci_restore_standard_config(struct pci_dev *pci_dev)
{
	pci_update_current_state(pci_dev, PCI_UNKNOWN);

	if (pci_dev->current_state != PCI_D0) {
		int error = pci_set_power_state(pci_dev, PCI_D0);
		if (error)
			return error;
	}

	pci_restore_state(pci_dev);
	pci_pme_restore(pci_dev);
	return 0;
}

#endif

#ifdef CONFIG_PM_SLEEP

static void pci_pm_default_resume_early(struct pci_dev *pci_dev)
{
	pci_power_up(pci_dev);
	pci_restore_state(pci_dev);
	pci_pme_restore(pci_dev);
}

/*
 * Default "suspend" method for devices that have no driver provided suspend,
 * or not even a driver at all (second part).
 */
static void pci_pm_set_unknown_state(struct pci_dev *pci_dev)
{
	/*
	 * mark its power state as "unknown", since we don't know if
	 * e.g. the BIOS will change its device state when we suspend.
	 */
	if (pci_dev->current_state == PCI_D0)
		pci_dev->current_state = PCI_UNKNOWN;
}

/*
 * Default "resume" method for devices that have no driver provided resume,
 * or not even a driver at all (second part).
 */
static int pci_pm_reenable_device(struct pci_dev *pci_dev)
{
	int retval;

	/* if the device was enabled before suspend, reenable */
	retval = pci_reenable_device(pci_dev);
	/*
	 * if the device was busmaster before the suspend, make it busmaster
	 * again
	 */
	if (pci_dev->is_busmaster)
		pci_set_master(pci_dev);

	return retval;
}

static int pci_legacy_suspend(struct device *dev, pm_message_t state)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	if (drv && drv->suspend) {
		pci_power_t prev = pci_dev->current_state;
		int error;

		error = drv->suspend(pci_dev, state);
		suspend_report_result(drv->suspend, error);
		if (error)
			return error;

		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
		    && pci_dev->current_state != PCI_UNKNOWN) {
			WARN_ONCE(pci_dev->current_state != prev,
				"PCI PM: Device state not saved by %pS\n",
				drv->suspend);
		}
	}

	pci_fixup_device(pci_fixup_suspend, pci_dev);

	return 0;
}

static int pci_legacy_suspend_late(struct device *dev, pm_message_t state)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	if (drv && drv->suspend_late) {
		pci_power_t prev = pci_dev->current_state;
		int error;

		error = drv->suspend_late(pci_dev, state);
		suspend_report_result(drv->suspend_late, error);
		if (error)
			return error;

		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
		    && pci_dev->current_state != PCI_UNKNOWN) {
			WARN_ONCE(pci_dev->current_state != prev,
				"PCI PM: Device state not saved by %pS\n",
				drv->suspend_late);
			goto Fixup;
		}
	}

	if (!pci_dev->state_saved)
		pci_save_state(pci_dev);

	pci_pm_set_unknown_state(pci_dev);

Fixup:
	pci_fixup_device(pci_fixup_suspend_late, pci_dev);

	return 0;
}

static int pci_legacy_resume_early(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	return drv && drv->resume_early ?
			drv->resume_early(pci_dev) : 0;
}

static int pci_legacy_resume(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *drv = pci_dev->driver;

	pci_fixup_device(pci_fixup_resume, pci_dev);

	return drv && drv->resume ?
			drv->resume(pci_dev) : pci_pm_reenable_device(pci_dev);
}

/* Auxiliary functions used by the new power management framework */

static void pci_pm_default_resume(struct pci_dev *pci_dev)
{
	pci_fixup_device(pci_fixup_resume, pci_dev);
	pci_enable_wake(pci_dev, PCI_D0, false);
}

static void pci_pm_default_suspend(struct pci_dev *pci_dev)
{
	/* Disable non-bridge devices without PM support */
	if (!pci_has_subordinate(pci_dev))
		pci_disable_enabled_device(pci_dev);
}

static bool pci_has_legacy_pm_support(struct pci_dev *pci_dev)
{
	struct pci_driver *drv = pci_dev->driver;
	bool ret = drv && (drv->suspend || drv->suspend_late || drv->resume
		|| drv->resume_early);

	/*
	 * Legacy PM support is used by default, so warn if the new framework is
	 * supported as well.  Drivers are supposed to support either the
	 * former, or the latter, but not both at the same time.
	 */
	WARN(ret && drv->driver.pm, "driver %s device %04x:%04x\n",
		drv->name, pci_dev->vendor, pci_dev->device);

	return ret;
}

/* New power management framework */

static int pci_pm_prepare(struct device *dev)
{
	struct device_driver *drv = dev->driver;

	if (drv && drv->pm && drv->pm->prepare) {
		int error = drv->pm->prepare(dev);
		if (error < 0)
			return error;

		if (!error && dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_PREPARE))
			return 0;
	}
	return pci_dev_keep_suspended(to_pci_dev(dev));
}

static void pci_pm_complete(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);

	pci_dev_complete_resume(pci_dev);
	pm_generic_complete(dev);

	/* Resume device if platform firmware has put it in reset-power-on */
	if (pm_runtime_suspended(dev) && pm_resume_via_firmware()) {
		pci_power_t pre_sleep_state = pci_dev->current_state;

		pci_update_current_state(pci_dev, pci_dev->current_state);
		if (pci_dev->current_state < pre_sleep_state)
			pm_request_resume(dev);
	}
}

#else /* !CONFIG_PM_SLEEP */

#define pci_pm_prepare	NULL
#define pci_pm_complete	NULL

#endif /* !CONFIG_PM_SLEEP */

#ifdef CONFIG_SUSPEND
static void pcie_pme_root_status_cleanup(struct pci_dev *pci_dev)
{
	/*
	 * Some BIOSes forget to clear Root PME Status bits after system
	 * wakeup, which breaks ACPI-based runtime wakeup on PCI Express.
	 * Clear those bits now just in case (shouldn't hurt).
	 */
	if (pci_is_pcie(pci_dev) &&
	    (pci_pcie_type(pci_dev) == PCI_EXP_TYPE_ROOT_PORT ||
	     pci_pcie_type(pci_dev) == PCI_EXP_TYPE_RC_EC))
		pcie_clear_root_pme_status(pci_dev);
}

static int pci_pm_suspend(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	pci_dev->skip_bus_pm = false;

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_suspend(dev, PMSG_SUSPEND);

	if (!pm) {
		pci_pm_default_suspend(pci_dev);
		return 0;
	}

	/*
	 * PCI devices suspended at run time may need to be resumed at this
	 * point, because in general it may be necessary to reconfigure them for
	 * system suspend.  Namely, if the device is expected to wake up the
	 * system from the sleep state, it may have to be reconfigured for this
	 * purpose, or if the device is not expected to wake up the system from
	 * the sleep state, it should be prevented from signaling wakeup events
	 * going forward.
	 *
	 * Also if the driver of the device does not indicate that its system
	 * suspend callbacks can cope with runtime-suspended devices, it is
	 * better to resume the device from runtime suspend here.
	 */
	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
	    !pci_dev_keep_suspended(pci_dev)) {
		pm_runtime_resume(dev);
		pci_dev->state_saved = false;
	}

	if (pm->suspend) {
		pci_power_t prev = pci_dev->current_state;
		int error;

		error = pm->suspend(dev);
		suspend_report_result(pm->suspend, error);
		if (error)
			return error;

		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
		    && pci_dev->current_state != PCI_UNKNOWN) {
			WARN_ONCE(pci_dev->current_state != prev,
				"PCI PM: State of device not saved by %pS\n",
				pm->suspend);
		}
	}

	return 0;
}

static int pci_pm_suspend_late(struct device *dev)
{
	if (dev_pm_smart_suspend_and_suspended(dev))
		return 0;

	pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));

	return pm_generic_suspend_late(dev);
}

static int pci_pm_suspend_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (dev_pm_smart_suspend_and_suspended(dev)) {
		dev->power.may_skip_resume = true;
		return 0;
	}

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_suspend_late(dev, PMSG_SUSPEND);

	if (!pm) {
		pci_save_state(pci_dev);
		goto Fixup;
	}

	if (pm->suspend_noirq) {
		pci_power_t prev = pci_dev->current_state;
		int error;

		error = pm->suspend_noirq(dev);
		suspend_report_result(pm->suspend_noirq, error);
		if (error)
			return error;

		if (!pci_dev->state_saved && pci_dev->current_state != PCI_D0
		    && pci_dev->current_state != PCI_UNKNOWN) {
			WARN_ONCE(pci_dev->current_state != prev,
				"PCI PM: State of device not saved by %pS\n",
				pm->suspend_noirq);
			goto Fixup;
		}
	}

	if (pci_dev->skip_bus_pm) {
		/*
		 * Either the device is a bridge with a child in D0 below it, or
		 * the function is running for the second time in a row without
		 * going through full resume, which is possible only during
		 * suspend-to-idle in a spurious wakeup case.  The device should
		 * be in D0 at this point, but if it is a bridge, it may be
		 * necessary to save its state.
		 */
		if (!pci_dev->state_saved)
			pci_save_state(pci_dev);
	} else if (!pci_dev->state_saved) {
		pci_save_state(pci_dev);
		if (pci_power_manageable(pci_dev))
			pci_prepare_to_sleep(pci_dev);
	}

	dev_dbg(dev, "PCI PM: Suspend power state: %s\n",
		pci_power_name(pci_dev->current_state));

	if (pci_dev->current_state == PCI_D0) {
		pci_dev->skip_bus_pm = true;
		/*
		 * Per PCI PM r1.2, table 6-1, a bridge must be in D0 if any
		 * downstream device is in D0, so avoid changing the power state
		 * of the parent bridge by setting the skip_bus_pm flag for it.
		 */
		if (pci_dev->bus->self)
			pci_dev->bus->self->skip_bus_pm = true;
	}

	if (pci_dev->skip_bus_pm && !pm_suspend_via_firmware()) {
		dev_dbg(dev, "PCI PM: Skipped\n");
		goto Fixup;
	}

	pci_pm_set_unknown_state(pci_dev);

	/*
	 * Some BIOSes from ASUS have a bug: If a USB EHCI host controller's
	 * PCI COMMAND register isn't 0, the BIOS assumes that the controller
	 * hasn't been quiesced and tries to turn it off.  If the controller
	 * is already in D3, this can hang or cause memory corruption.
	 *
	 * Since the value of the COMMAND register doesn't matter once the
	 * device has been suspended, we can safely set it to 0 here.
	 */
	if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
		pci_write_config_word(pci_dev, PCI_COMMAND, 0);

Fixup:
	pci_fixup_device(pci_fixup_suspend_late, pci_dev);

	/*
	 * If the target system sleep state is suspend-to-idle, it is sufficient
	 * to check whether or not the device's wakeup settings are good for
	 * runtime PM.  Otherwise, the pm_resume_via_firmware() check will cause
	 * pci_pm_complete() to take care of fixing up the device's state
	 * anyway, if need be.
	 */
	dev->power.may_skip_resume = device_may_wakeup(dev) ||
					!device_can_wakeup(dev);

	return 0;
}

static int pci_pm_resume_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct device_driver *drv = dev->driver;
	int error = 0;

	if (dev_pm_may_skip_resume(dev))
		return 0;

	/*
	 * Devices with DPM_FLAG_SMART_SUSPEND may be left in runtime suspend
	 * during system suspend, so update their runtime PM status to "active"
	 * as they are going to be put into D0 shortly.
	 */
	if (dev_pm_smart_suspend_and_suspended(dev))
		pm_runtime_set_active(dev);

	/*
	 * In the suspend-to-idle case, devices left in D0 during suspend will
	 * stay in D0, so it is not necessary to restore or update their
	 * configuration here and attempting to put them into D0 again may
	 * confuse some firmware, so avoid doing that.
	 */
	if (!pci_dev->skip_bus_pm || pm_suspend_via_firmware())
		pci_pm_default_resume_early(pci_dev);

	pci_fixup_device(pci_fixup_resume_early, pci_dev);

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume_early(dev);

	pcie_pme_root_status_cleanup(pci_dev);

	if (drv && drv->pm && drv->pm->resume_noirq)
		error = drv->pm->resume_noirq(dev);

	return error;
}

static int pci_pm_resume(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
	int error = 0;

	/*
	 * This is necessary for the suspend error path in which resume is
	 * called without restoring the standard config registers of the device.
	 */
	if (pci_dev->state_saved)
		pci_restore_standard_config(pci_dev);

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume(dev);

	pci_pm_default_resume(pci_dev);

	if (pm) {
		if (pm->resume)
			error = pm->resume(dev);
	} else {
		pci_pm_reenable_device(pci_dev);
	}

	return error;
}

#else /* !CONFIG_SUSPEND */

#define pci_pm_suspend		NULL
#define pci_pm_suspend_late	NULL
#define pci_pm_suspend_noirq	NULL
#define pci_pm_resume		NULL
#define pci_pm_resume_noirq	NULL

#endif /* !CONFIG_SUSPEND */

#ifdef CONFIG_HIBERNATE_CALLBACKS


/*
 * pcibios_pm_ops - provide arch-specific hooks when a PCI device is doing
 * a hibernate transition
 */
struct dev_pm_ops __weak pcibios_pm_ops;

static int pci_pm_freeze(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_suspend(dev, PMSG_FREEZE);

	if (!pm) {
		pci_pm_default_suspend(pci_dev);
		return 0;
	}

	/*
	 * This used to be done in pci_pm_prepare() for all devices and some
	 * drivers may depend on it, so do it here.  Ideally, runtime-suspended
	 * devices should not be touched during freeze/thaw transitions,
	 * however.
	 */
	if (!dev_pm_smart_suspend_and_suspended(dev)) {
		pm_runtime_resume(dev);
		pci_dev->state_saved = false;
	}

	if (pm->freeze) {
		int error;

		error = pm->freeze(dev);
		suspend_report_result(pm->freeze, error);
		if (error)
			return error;
	}

	return 0;
}

static int pci_pm_freeze_late(struct device *dev)
{
	if (dev_pm_smart_suspend_and_suspended(dev))
		return 0;

	return pm_generic_freeze_late(dev);
}

static int pci_pm_freeze_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct device_driver *drv = dev->driver;

	if (dev_pm_smart_suspend_and_suspended(dev))
		return 0;

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_suspend_late(dev, PMSG_FREEZE);

	if (drv && drv->pm && drv->pm->freeze_noirq) {
		int error;

		error = drv->pm->freeze_noirq(dev);
		suspend_report_result(drv->pm->freeze_noirq, error);
		if (error)
			return error;
	}

	if (!pci_dev->state_saved)
		pci_save_state(pci_dev);

	pci_pm_set_unknown_state(pci_dev);

	if (pcibios_pm_ops.freeze_noirq)
		return pcibios_pm_ops.freeze_noirq(dev);

	return 0;
}

static int pci_pm_thaw_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct device_driver *drv = dev->driver;
	int error = 0;

	/*
	 * If the device is in runtime suspend, the code below may not work
	 * correctly with it, so skip that code and make the PM core skip all of
	 * the subsequent "thaw" callbacks for the device.
	 */
	if (dev_pm_smart_suspend_and_suspended(dev)) {
		dev_pm_skip_next_resume_phases(dev);
		return 0;
	}

	if (pcibios_pm_ops.thaw_noirq) {
		error = pcibios_pm_ops.thaw_noirq(dev);
		if (error)
			return error;
	}

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume_early(dev);

	/*
	 * pci_restore_state() requires the device to be in D0 (because of MSI
	 * restoration among other things), so force it into D0 in case the
	 * driver's "freeze" callbacks put it into a low-power state directly.
	 */
	pci_set_power_state(pci_dev, PCI_D0);
	pci_restore_state(pci_dev);

	if (drv && drv->pm && drv->pm->thaw_noirq)
		error = drv->pm->thaw_noirq(dev);

	return error;
}

static int pci_pm_thaw(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
	int error = 0;

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume(dev);

	if (pm) {
		if (pm->thaw)
			error = pm->thaw(dev);
	} else {
		pci_pm_reenable_device(pci_dev);
	}

	pci_dev->state_saved = false;

	return error;
}

static int pci_pm_poweroff(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_suspend(dev, PMSG_HIBERNATE);

	if (!pm) {
		pci_pm_default_suspend(pci_dev);
		return 0;
	}

	/* The reason to do that is the same as in pci_pm_suspend(). */
	if (!dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) ||
	    !pci_dev_keep_suspended(pci_dev))
		pm_runtime_resume(dev);

	pci_dev->state_saved = false;
	if (pm->poweroff) {
		int error;

		error = pm->poweroff(dev);
		suspend_report_result(pm->poweroff, error);
		if (error)
			return error;
	}

	return 0;
}

static int pci_pm_poweroff_late(struct device *dev)
{
	if (dev_pm_smart_suspend_and_suspended(dev))
		return 0;

	pci_fixup_device(pci_fixup_suspend, to_pci_dev(dev));

	return pm_generic_poweroff_late(dev);
}

static int pci_pm_poweroff_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct device_driver *drv = dev->driver;

	if (dev_pm_smart_suspend_and_suspended(dev))
		return 0;

	if (pci_has_legacy_pm_support(to_pci_dev(dev)))
		return pci_legacy_suspend_late(dev, PMSG_HIBERNATE);

	if (!drv || !drv->pm) {
		pci_fixup_device(pci_fixup_suspend_late, pci_dev);
		return 0;
	}

	if (drv->pm->poweroff_noirq) {
		int error;

		error = drv->pm->poweroff_noirq(dev);
		suspend_report_result(drv->pm->poweroff_noirq, error);
		if (error)
			return error;
	}

	if (!pci_dev->state_saved && !pci_has_subordinate(pci_dev))
		pci_prepare_to_sleep(pci_dev);

	/*
	 * The reason for doing this here is the same as for the analogous code
	 * in pci_pm_suspend_noirq().
	 */
	if (pci_dev->class == PCI_CLASS_SERIAL_USB_EHCI)
		pci_write_config_word(pci_dev, PCI_COMMAND, 0);

	pci_fixup_device(pci_fixup_suspend_late, pci_dev);

	if (pcibios_pm_ops.poweroff_noirq)
		return pcibios_pm_ops.poweroff_noirq(dev);

	return 0;
}

static int pci_pm_restore_noirq(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct device_driver *drv = dev->driver;
	int error = 0;

	/* This is analogous to the pci_pm_resume_noirq() case. */
	if (dev_pm_smart_suspend_and_suspended(dev))
		pm_runtime_set_active(dev);

	if (pcibios_pm_ops.restore_noirq) {
		error = pcibios_pm_ops.restore_noirq(dev);
		if (error)
			return error;
	}

	pci_pm_default_resume_early(pci_dev);
	pci_fixup_device(pci_fixup_resume_early, pci_dev);

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume_early(dev);

	if (drv && drv->pm && drv->pm->restore_noirq)
		error = drv->pm->restore_noirq(dev);

	return error;
}

static int pci_pm_restore(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
	int error = 0;

	/*
	 * This is necessary for the hibernation error path in which restore is
	 * called without restoring the standard config registers of the device.
	 */
	if (pci_dev->state_saved)
		pci_restore_standard_config(pci_dev);

	if (pci_has_legacy_pm_support(pci_dev))
		return pci_legacy_resume(dev);

	pci_pm_default_resume(pci_dev);

	if (pm) {
		if (pm->restore)
			error = pm->restore(dev);
	} else {
		pci_pm_reenable_device(pci_dev);
	}

	return error;
}

#else /* !CONFIG_HIBERNATE_CALLBACKS */

#define pci_pm_freeze		NULL
#define pci_pm_freeze_late	NULL
#define pci_pm_freeze_noirq	NULL
#define pci_pm_thaw		NULL
#define pci_pm_thaw_noirq	NULL
#define pci_pm_poweroff		NULL
#define pci_pm_poweroff_late	NULL
#define pci_pm_poweroff_noirq	NULL
#define pci_pm_restore		NULL
#define pci_pm_restore_noirq	NULL

#endif /* !CONFIG_HIBERNATE_CALLBACKS */

#ifdef CONFIG_PM

static int pci_pm_runtime_suspend(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
	pci_power_t prev = pci_dev->current_state;
	int error;

	/*
	 * If pci_dev->driver is not set (unbound), we leave the device in D0,
	 * but it may go to D3cold when the bridge above it runtime suspends.
	 * Save its config space in case that happens.
	 */
	if (!pci_dev->driver) {
		pci_save_state(pci_dev);
		return 0;
	}

	pci_dev->state_saved = false;
	if (pm && pm->runtime_suspend) {
		error = pm->runtime_suspend(dev);
		/*
		 * -EBUSY and -EAGAIN is used to request the runtime PM core
		 * to schedule a new suspend, so log the event only with debug
		 * log level.
		 */
		if (error == -EBUSY || error == -EAGAIN) {
			dev_dbg(dev, "can't suspend now (%ps returned %d)\n",
				pm->runtime_suspend, error);
			return error;
		} else if (error) {
			dev_err(dev, "can't suspend (%ps returned %d)\n",
				pm->runtime_suspend, error);
			return error;
		}
	}

	pci_fixup_device(pci_fixup_suspend, pci_dev);

	if (pm && pm->runtime_suspend
	    && !pci_dev->state_saved && pci_dev->current_state != PCI_D0
	    && pci_dev->current_state != PCI_UNKNOWN) {
		WARN_ONCE(pci_dev->current_state != prev,
			"PCI PM: State of device not saved by %pS\n",
			pm->runtime_suspend);
		return 0;
	}

	if (!pci_dev->state_saved) {
		pci_save_state(pci_dev);
		pci_finish_runtime_suspend(pci_dev);
	}

	return 0;
}

static int pci_pm_runtime_resume(struct device *dev)
{
	int rc = 0;
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;

	/*
	 * Restoring config space is necessary even if the device is not bound
	 * to a driver because although we left it in D0, it may have gone to
	 * D3cold when the bridge above it runtime suspended.
	 */
	pci_restore_standard_config(pci_dev);

	if (!pci_dev->driver)
		return 0;

	pci_fixup_device(pci_fixup_resume_early, pci_dev);
	pci_enable_wake(pci_dev, PCI_D0, false);
	pci_fixup_device(pci_fixup_resume, pci_dev);

	if (pm && pm->runtime_resume)
		rc = pm->runtime_resume(dev);

	pci_dev->runtime_d3cold = false;

	return rc;
}

static int pci_pm_runtime_idle(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
	int ret = 0;

	/*
	 * If pci_dev->driver is not set (unbound), the device should
	 * always remain in D0 regardless of the runtime PM status
	 */
	if (!pci_dev->driver)
		return 0;

	if (!pm)
		return -ENOSYS;

	if (pm->runtime_idle)
		ret = pm->runtime_idle(dev);

	return ret;
}

static const struct dev_pm_ops pci_dev_pm_ops = {
	.prepare = pci_pm_prepare,
	.complete = pci_pm_complete,
	.suspend = pci_pm_suspend,
	.suspend_late = pci_pm_suspend_late,
	.resume = pci_pm_resume,
	.freeze = pci_pm_freeze,
	.freeze_late = pci_pm_freeze_late,
	.thaw = pci_pm_thaw,
	.poweroff = pci_pm_poweroff,
	.poweroff_late = pci_pm_poweroff_late,
	.restore = pci_pm_restore,
	.suspend_noirq = pci_pm_suspend_noirq,
	.resume_noirq = pci_pm_resume_noirq,
	.freeze_noirq = pci_pm_freeze_noirq,
	.thaw_noirq = pci_pm_thaw_noirq,
	.poweroff_noirq = pci_pm_poweroff_noirq,
	.restore_noirq = pci_pm_restore_noirq,
	.runtime_suspend = pci_pm_runtime_suspend,
	.runtime_resume = pci_pm_runtime_resume,
	.runtime_idle = pci_pm_runtime_idle,
};

#define PCI_PM_OPS_PTR	(&pci_dev_pm_ops)

#else /* !CONFIG_PM */

#define pci_pm_runtime_suspend	NULL
#define pci_pm_runtime_resume	NULL
#define pci_pm_runtime_idle	NULL

#define PCI_PM_OPS_PTR	NULL

#endif /* !CONFIG_PM */

/**
 * __pci_register_driver - register a new pci driver
 * @drv: the driver structure to register
 * @owner: owner module of drv
 * @mod_name: module name string
 *
 * Adds the driver structure to the list of registered drivers.
 * Returns a negative value on error, otherwise 0.
 * If no error occurred, the driver remains registered even if
 * no device was claimed during registration.
 */
int __pci_register_driver(struct pci_driver *drv, struct module *owner,
			  const char *mod_name)
{
	/* initialize common driver fields */
	drv->driver.name = drv->name;
	drv->driver.bus = &pci_bus_type;
	drv->driver.owner = owner;
	drv->driver.mod_name = mod_name;
	drv->driver.groups = drv->groups;

	spin_lock_init(&drv->dynids.lock);
	INIT_LIST_HEAD(&drv->dynids.list);

	/* register with core */
	return driver_register(&drv->driver);
}
EXPORT_SYMBOL(__pci_register_driver);

/**
 * pci_unregister_driver - unregister a pci driver
 * @drv: the driver structure to unregister
 *
 * Deletes the driver structure from the list of registered PCI drivers,
 * gives it a chance to clean up by calling its remove() function for
 * each device it was responsible for, and marks those devices as
 * driverless.
 */

void pci_unregister_driver(struct pci_driver *drv)
{
	driver_unregister(&drv->driver);
	pci_free_dynids(drv);
}
EXPORT_SYMBOL(pci_unregister_driver);

static struct pci_driver pci_compat_driver = {
	.name = "compat"
};

/**
 * pci_dev_driver - get the pci_driver of a device
 * @dev: the device to query
 *
 * Returns the appropriate pci_driver structure or %NULL if there is no
 * registered driver for the device.
 */
struct pci_driver *pci_dev_driver(const struct pci_dev *dev)
{
	if (dev->driver)
		return dev->driver;
	else {
		int i;
		for (i = 0; i <= PCI_ROM_RESOURCE; i++)
			if (dev->resource[i].flags & IORESOURCE_BUSY)
				return &pci_compat_driver;
	}
	return NULL;
}
EXPORT_SYMBOL(pci_dev_driver);

/**
 * pci_bus_match - Tell if a PCI device structure has a matching PCI device id structure
 * @dev: the PCI device structure to match against
 * @drv: the device driver to search for matching PCI device id structures
 *
 * Used by a driver to check whether a PCI device present in the
 * system is in its list of supported devices. Returns the matching
 * pci_device_id structure or %NULL if there is no match.
 */
static int pci_bus_match(struct device *dev, struct device_driver *drv)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct pci_driver *pci_drv;
	const struct pci_device_id *found_id;

	if (!pci_dev->match_driver)
		return 0;

	pci_drv = to_pci_driver(drv);
	found_id = pci_match_device(pci_drv, pci_dev);
	if (found_id)
		return 1;

	return 0;
}

/**
 * pci_dev_get - increments the reference count of the pci device structure
 * @dev: the device being referenced
 *
 * Each live reference to a device should be refcounted.
 *
 * Drivers for PCI devices should normally record such references in
 * their probe() methods, when they bind to a device, and release
 * them by calling pci_dev_put(), in their disconnect() methods.
 *
 * A pointer to the device with the incremented reference counter is returned.
 */
struct pci_dev *pci_dev_get(struct pci_dev *dev)
{
	if (dev)
		get_device(&dev->dev);
	return dev;
}
EXPORT_SYMBOL(pci_dev_get);

/**
 * pci_dev_put - release a use of the pci device structure
 * @dev: device that's been disconnected
 *
 * Must be called when a user of a device is finished with it.  When the last
 * user of the device calls this function, the memory of the device is freed.
 */
void pci_dev_put(struct pci_dev *dev)
{
	if (dev)
		put_device(&dev->dev);
}
EXPORT_SYMBOL(pci_dev_put);

static int pci_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct pci_dev *pdev;

	if (!dev)
		return -ENODEV;

	pdev = to_pci_dev(dev);

	if (add_uevent_var(env, "PCI_CLASS=%04X", pdev->class))
		return -ENOMEM;

	if (add_uevent_var(env, "PCI_ID=%04X:%04X", pdev->vendor, pdev->device))
		return -ENOMEM;

	if (add_uevent_var(env, "PCI_SUBSYS_ID=%04X:%04X", pdev->subsystem_vendor,
			   pdev->subsystem_device))
		return -ENOMEM;

	if (add_uevent_var(env, "PCI_SLOT_NAME=%s", pci_name(pdev)))
		return -ENOMEM;

	if (add_uevent_var(env, "MODALIAS=pci:v%08Xd%08Xsv%08Xsd%08Xbc%02Xsc%02Xi%02X",
			   pdev->vendor, pdev->device,
			   pdev->subsystem_vendor, pdev->subsystem_device,
			   (u8)(pdev->class >> 16), (u8)(pdev->class >> 8),
			   (u8)(pdev->class)))
		return -ENOMEM;

	return 0;
}

#if defined(CONFIG_PCIEPORTBUS) || defined(CONFIG_EEH)
/**
 * pci_uevent_ers - emit a uevent during recovery path of PCI device
 * @pdev: PCI device undergoing error recovery
 * @err_type: type of error event
 */
void pci_uevent_ers(struct pci_dev *pdev, enum pci_ers_result err_type)
{
	int idx = 0;
	char *envp[3];

	switch (err_type) {
	case PCI_ERS_RESULT_NONE:
	case PCI_ERS_RESULT_CAN_RECOVER:
		envp[idx++] = "ERROR_EVENT=BEGIN_RECOVERY";
		envp[idx++] = "DEVICE_ONLINE=0";
		break;
	case PCI_ERS_RESULT_RECOVERED:
		envp[idx++] = "ERROR_EVENT=SUCCESSFUL_RECOVERY";
		envp[idx++] = "DEVICE_ONLINE=1";
		break;
	case PCI_ERS_RESULT_DISCONNECT:
		envp[idx++] = "ERROR_EVENT=FAILED_RECOVERY";
		envp[idx++] = "DEVICE_ONLINE=0";
		break;
	default:
		break;
	}

	if (idx > 0) {
		envp[idx++] = NULL;
		kobject_uevent_env(&pdev->dev.kobj, KOBJ_CHANGE, envp);
	}
}
#endif

static int pci_bus_num_vf(struct device *dev)
{
	return pci_num_vf(to_pci_dev(dev));
}

/**
 * pci_dma_configure - Setup DMA configuration
 * @dev: ptr to dev structure
 *
 * Function to update PCI devices's DMA configuration using the same
 * info from the OF node or ACPI node of host bridge's parent (if any).
 */
static int pci_dma_configure(struct device *dev)
{
	struct device *bridge;
	int ret = 0;

	bridge = pci_get_host_bridge_device(to_pci_dev(dev));

	if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
	    bridge->parent->of_node) {
		ret = of_dma_configure(dev, bridge->parent->of_node, true);
	} else if (has_acpi_companion(bridge)) {
		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);

		ret = acpi_dma_configure(dev, acpi_get_dma_attr(adev));
	}

	pci_put_host_bridge_device(bridge);
	return ret;
}

struct bus_type pci_bus_type = {
	.name		= "pci",
	.match		= pci_bus_match,
	.uevent		= pci_uevent,
	.probe		= pci_device_probe,
	.remove		= pci_device_remove,
	.shutdown	= pci_device_shutdown,
	.dev_groups	= pci_dev_groups,
	.bus_groups	= pci_bus_groups,
	.drv_groups	= pci_drv_groups,
	.pm		= PCI_PM_OPS_PTR,
	.num_vf		= pci_bus_num_vf,
	.dma_configure	= pci_dma_configure,
};
EXPORT_SYMBOL(pci_bus_type);

#ifdef CONFIG_PCIEPORTBUS
static int pcie_port_bus_match(struct device *dev, struct device_driver *drv)
{
	struct pcie_device *pciedev;
	struct pcie_port_service_driver *driver;

	if (drv->bus != &pcie_port_bus_type || dev->bus != &pcie_port_bus_type)
		return 0;

	pciedev = to_pcie_device(dev);
	driver = to_service_driver(drv);

	if (driver->service != pciedev->service)
		return 0;

	if (driver->port_type != PCIE_ANY_PORT &&
	    driver->port_type != pci_pcie_type(pciedev->port))
		return 0;

	return 1;
}

struct bus_type pcie_port_bus_type = {
	.name		= "pci_express",
	.match		= pcie_port_bus_match,
};
EXPORT_SYMBOL_GPL(pcie_port_bus_type);
#endif

static int __init pci_driver_init(void)
{
	int ret;

	ret = bus_register(&pci_bus_type);
	if (ret)
		return ret;

#ifdef CONFIG_PCIEPORTBUS
	ret = bus_register(&pcie_port_bus_type);
	if (ret)
		return ret;
#endif
	dma_debug_add_bus(&pci_bus_type);
	return 0;
}
postcore_initcall(pci_driver_init);