summaryrefslogtreecommitdiffstats
path: root/drivers/pci/hotplug/acpiphp_glue.c
blob: 22006f2d9dd5780e20734465587b7dabfb4a43bb (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
/*
 * ACPI PCI HotPlug glue functions to ACPI CA subsystem
 *
 * Copyright (C) 2002,2003 Takayoshi Kochi (t-kochi@bq.jp.nec.com)
 * Copyright (C) 2002 Hiroshi Aono (h-aono@ap.jp.nec.com)
 * Copyright (C) 2002,2003 NEC Corporation
 * Copyright (C) 2003-2005 Matthew Wilcox (matthew.wilcox@hp.com)
 * Copyright (C) 2003-2005 Hewlett Packard
 * Copyright (C) 2005 Rajesh Shah (rajesh.shah@intel.com)
 * Copyright (C) 2005 Intel Corporation
 *
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * Send feedback to <kristen.c.accardi@intel.com>
 *
 */

/*
 * Lifetime rules for pci_dev:
 *  - The one in acpiphp_bridge has its refcount elevated by pci_get_slot()
 *    when the bridge is scanned and it loses a refcount when the bridge
 *    is removed.
 *  - When a P2P bridge is present, we elevate the refcount on the subordinate
 *    bus. It loses the refcount when the the driver unloads.
 */

#include <linux/init.h>
#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/pci-acpi.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/acpi.h>

#include "../pci.h"
#include "acpiphp.h"

static LIST_HEAD(bridge_list);

#define MY_NAME "acpiphp_glue"

static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
static void acpiphp_sanitize_bus(struct pci_bus *bus);
static void acpiphp_set_hpp_values(struct pci_bus *bus);
static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);

/* callback routine to check for the existence of a pci dock device */
static acpi_status
is_pci_dock_device(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = (int *)context;

	if (is_dock_device(handle)) {
		(*count)++;
		return AE_CTRL_TERMINATE;
	} else {
		return AE_OK;
	}
}

/*
 * the _DCK method can do funny things... and sometimes not
 * hah-hah funny.
 *
 * TBD - figure out a way to only call fixups for
 * systems that require them.
 */
static int post_dock_fixups(struct notifier_block *nb, unsigned long val,
	void *v)
{
	struct acpiphp_func *func = container_of(nb, struct acpiphp_func, nb);
	struct pci_bus *bus = func->slot->bridge->pci_bus;
	u32 buses;

	if (!bus->self)
		return  NOTIFY_OK;

	/* fixup bad _DCK function that rewrites
	 * secondary bridge on slot
	 */
	pci_read_config_dword(bus->self,
			PCI_PRIMARY_BUS,
			&buses);

	if (((buses >> 8) & 0xff) != bus->busn_res.start) {
		buses = (buses & 0xff000000)
			| ((unsigned int)(bus->primary)     <<  0)
			| ((unsigned int)(bus->busn_res.start)   <<  8)
			| ((unsigned int)(bus->busn_res.end) << 16);
		pci_write_config_dword(bus->self, PCI_PRIMARY_BUS, buses);
	}
	return NOTIFY_OK;
}


static const struct acpi_dock_ops acpiphp_dock_ops = {
	.handler = handle_hotplug_event_func,
};

/* Check whether the PCI device is managed by native PCIe hotplug driver */
static bool device_is_managed_by_native_pciehp(struct pci_dev *pdev)
{
	u32 reg32;
	acpi_handle tmp;
	struct acpi_pci_root *root;

	/* Check whether the PCIe port supports native PCIe hotplug */
	if (pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &reg32))
		return false;
	if (!(reg32 & PCI_EXP_SLTCAP_HPC))
		return false;

	/*
	 * Check whether native PCIe hotplug has been enabled for
	 * this PCIe hierarchy.
	 */
	tmp = acpi_find_root_bridge_handle(pdev);
	if (!tmp)
		return false;
	root = acpi_pci_find_root(tmp);
	if (!root)
		return false;
	if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
		return false;

	return true;
}

/* callback routine to register each ACPI PCI slot object */
static acpi_status
register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	struct acpiphp_bridge *bridge = (struct acpiphp_bridge *)context;
	struct acpiphp_slot *slot;
	struct acpiphp_func *newfunc;
	acpi_handle tmp;
	acpi_status status = AE_OK;
	unsigned long long adr, sun;
	int device, function, retval;
	struct pci_bus *pbus = bridge->pci_bus;
	struct pci_dev *pdev;

	if (!acpi_pci_check_ejectable(pbus, handle) && !is_dock_device(handle))
		return AE_OK;

	status = acpi_evaluate_integer(handle, "_ADR", NULL, &adr);
	if (ACPI_FAILURE(status)) {
		warn("can't evaluate _ADR (%#x)\n", status);
		return AE_OK;
	}

	device = (adr >> 16) & 0xffff;
	function = adr & 0xffff;

	pdev = pbus->self;
	if (pdev && device_is_managed_by_native_pciehp(pdev))
		return AE_OK;

	newfunc = kzalloc(sizeof(struct acpiphp_func), GFP_KERNEL);
	if (!newfunc)
		return AE_NO_MEMORY;

	INIT_LIST_HEAD(&newfunc->sibling);
	newfunc->handle = handle;
	newfunc->function = function;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_EJ0", &tmp)))
		newfunc->flags = FUNC_HAS_EJ0;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_STA", &tmp)))
		newfunc->flags |= FUNC_HAS_STA;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_PS0", &tmp)))
		newfunc->flags |= FUNC_HAS_PS0;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_PS3", &tmp)))
		newfunc->flags |= FUNC_HAS_PS3;

	if (ACPI_SUCCESS(acpi_get_handle(handle, "_DCK", &tmp)))
		newfunc->flags |= FUNC_HAS_DCK;

	status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
	if (ACPI_FAILURE(status)) {
		/*
		 * use the count of the number of slots we've found
		 * for the number of the slot
		 */
		sun = bridge->nr_slots+1;
	}

	/* search for objects that share the same slot */
	for (slot = bridge->slots; slot; slot = slot->next)
		if (slot->device == device) {
			if (slot->sun != sun)
				warn("sibling found, but _SUN doesn't match!\n");
			break;
		}

	if (!slot) {
		slot = kzalloc(sizeof(struct acpiphp_slot), GFP_KERNEL);
		if (!slot) {
			kfree(newfunc);
			return AE_NO_MEMORY;
		}

		slot->bridge = bridge;
		slot->device = device;
		slot->sun = sun;
		INIT_LIST_HEAD(&slot->funcs);
		mutex_init(&slot->crit_sect);

		slot->next = bridge->slots;
		bridge->slots = slot;

		bridge->nr_slots++;

		dbg("found ACPI PCI Hotplug slot %llu at PCI %04x:%02x:%02x\n",
		    slot->sun, pci_domain_nr(pbus), pbus->number, device);
		retval = acpiphp_register_hotplug_slot(slot);
		if (retval) {
			if (retval == -EBUSY)
				warn("Slot %llu already registered by another "
					"hotplug driver\n", slot->sun);
			else
				warn("acpiphp_register_hotplug_slot failed "
					"(err code = 0x%x)\n", retval);
			goto err_exit;
		}
	}

	newfunc->slot = slot;
	list_add_tail(&newfunc->sibling, &slot->funcs);

	pdev = pci_get_slot(pbus, PCI_DEVFN(device, function));
	if (pdev) {
		slot->flags |= (SLOT_ENABLED | SLOT_POWEREDON);
		pci_dev_put(pdev);
	}

	if (is_dock_device(handle)) {
		/* we don't want to call this device's _EJ0
		 * because we want the dock notify handler
		 * to call it after it calls _DCK
		 */
		newfunc->flags &= ~FUNC_HAS_EJ0;
		if (register_hotplug_dock_device(handle,
			&acpiphp_dock_ops, newfunc))
			dbg("failed to register dock device\n");

		/* we need to be notified when dock events happen
		 * outside of the hotplug operation, since we may
		 * need to do fixups before we can hotplug.
		 */
		newfunc->nb.notifier_call = post_dock_fixups;
		if (register_dock_notifier(&newfunc->nb))
			dbg("failed to register a dock notifier");
	}

	/* install notify handler */
	if (!(newfunc->flags & FUNC_HAS_DCK)) {
		status = acpi_install_notify_handler(handle,
					     ACPI_SYSTEM_NOTIFY,
					     handle_hotplug_event_func,
					     newfunc);

		if (ACPI_FAILURE(status))
			err("failed to register interrupt notify handler\n");
	} else
		status = AE_OK;

	return status;

 err_exit:
	bridge->nr_slots--;
	bridge->slots = slot->next;
	kfree(slot);
	kfree(newfunc);

	return AE_OK;
}


/* see if it's worth looking at this bridge */
static int detect_ejectable_slots(acpi_handle handle)
{
	int found = acpi_pci_detect_ejectable(handle);
	if (!found) {
		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				    is_pci_dock_device, NULL, (void *)&found, NULL);
	}
	return found;
}

/* initialize miscellaneous stuff for both root and PCI-to-PCI bridge */
static void init_bridge_misc(struct acpiphp_bridge *bridge)
{
	acpi_status status;

	/* must be added to the list prior to calling register_slot */
	list_add(&bridge->list, &bridge_list);

	/* register all slot objects under this bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, bridge->handle, (u32)1,
				     register_slot, NULL, bridge, NULL);
	if (ACPI_FAILURE(status)) {
		list_del(&bridge->list);
		return;
	}

	/* install notify handler */
	if (bridge->type != BRIDGE_TYPE_HOST) {
		if ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func) {
			status = acpi_remove_notify_handler(bridge->func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func);
			if (ACPI_FAILURE(status))
				err("failed to remove notify handler\n");
		}
		status = acpi_install_notify_handler(bridge->handle,
					     ACPI_SYSTEM_NOTIFY,
					     handle_hotplug_event_bridge,
					     bridge);

		if (ACPI_FAILURE(status)) {
			err("failed to register interrupt notify handler\n");
		}
	}
}


/* find acpiphp_func from acpiphp_bridge */
static struct acpiphp_func *acpiphp_bridge_handle_to_function(acpi_handle handle)
{
	struct acpiphp_bridge *bridge;
	struct acpiphp_slot *slot;
	struct acpiphp_func *func;

	list_for_each_entry(bridge, &bridge_list, list) {
		for (slot = bridge->slots; slot; slot = slot->next) {
			list_for_each_entry(func, &slot->funcs, sibling) {
				if (func->handle == handle)
					return func;
			}
		}
	}

	return NULL;
}


static inline void config_p2p_bridge_flags(struct acpiphp_bridge *bridge)
{
	acpi_handle dummy_handle;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_STA", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_STA;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_EJ0", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_EJ0;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_PS0", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_PS0;

	if (ACPI_SUCCESS(acpi_get_handle(bridge->handle,
					"_PS3", &dummy_handle)))
		bridge->flags |= BRIDGE_HAS_PS3;

	/* is this ejectable p2p bridge? */
	if (bridge->flags & BRIDGE_HAS_EJ0) {
		struct acpiphp_func *func;

		dbg("found ejectable p2p bridge\n");

		/* make link between PCI bridge and PCI function */
		func = acpiphp_bridge_handle_to_function(bridge->handle);
		if (!func)
			return;
		bridge->func = func;
		func->bridge = bridge;
	}
}


/* allocate and initialize host bridge data structure */
static void add_host_bridge(struct acpi_pci_root *root)
{
	struct acpiphp_bridge *bridge;
	acpi_handle handle = root->device->handle;

	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
	if (bridge == NULL)
		return;

	bridge->type = BRIDGE_TYPE_HOST;
	bridge->handle = handle;

	bridge->pci_bus = root->bus;

	init_bridge_misc(bridge);
}


/* allocate and initialize PCI-to-PCI bridge data structure */
static void add_p2p_bridge(acpi_handle *handle)
{
	struct acpiphp_bridge *bridge;

	bridge = kzalloc(sizeof(struct acpiphp_bridge), GFP_KERNEL);
	if (bridge == NULL) {
		err("out of memory\n");
		return;
	}

	bridge->type = BRIDGE_TYPE_P2P;
	bridge->handle = handle;
	config_p2p_bridge_flags(bridge);

	bridge->pci_dev = acpi_get_pci_dev(handle);
	bridge->pci_bus = bridge->pci_dev->subordinate;
	if (!bridge->pci_bus) {
		err("This is not a PCI-to-PCI bridge!\n");
		goto err;
	}

	/*
	 * Grab a ref to the subordinate PCI bus in case the bus is
	 * removed via PCI core logical hotplug. The ref pins the bus
	 * (which we access during module unload).
	 */
	get_device(&bridge->pci_bus->dev);

	init_bridge_misc(bridge);
	return;
 err:
	pci_dev_put(bridge->pci_dev);
	kfree(bridge);
	return;
}


/* callback routine to find P2P bridges */
static acpi_status
find_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	acpi_status status;
	struct pci_dev *dev;

	dev = acpi_get_pci_dev(handle);
	if (!dev || !dev->subordinate)
		goto out;

	/* check if this bridge has ejectable slots */
	if ((detect_ejectable_slots(handle) > 0)) {
		dbg("found PCI-to-PCI bridge at PCI %s\n", pci_name(dev));
		add_p2p_bridge(handle);
	}

	/* search P2P bridges under this p2p bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				     find_p2p_bridge, NULL, NULL, NULL);
	if (ACPI_FAILURE(status))
		warn("find_p2p_bridge failed (error code = 0x%x)\n", status);

 out:
	pci_dev_put(dev);
	return AE_OK;
}


/* find hot-pluggable slots, and then find P2P bridge */
static int add_bridge(struct acpi_pci_root *root)
{
	acpi_status status;
	unsigned long long tmp;
	acpi_handle dummy_handle;
	acpi_handle handle = root->device->handle;

	/* if the bridge doesn't have _STA, we assume it is always there */
	status = acpi_get_handle(handle, "_STA", &dummy_handle);
	if (ACPI_SUCCESS(status)) {
		status = acpi_evaluate_integer(handle, "_STA", NULL, &tmp);
		if (ACPI_FAILURE(status)) {
			dbg("%s: _STA evaluation failure\n", __func__);
			return 0;
		}
		if ((tmp & ACPI_STA_FUNCTIONING) == 0)
			/* don't register this object */
			return 0;
	}

	/* check if this bridge has ejectable slots */
	if (detect_ejectable_slots(handle) > 0) {
		dbg("found PCI host-bus bridge with hot-pluggable slots\n");
		add_host_bridge(root);
	}

	/* search P2P bridges under this host bridge */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				     find_p2p_bridge, NULL, NULL, NULL);

	if (ACPI_FAILURE(status))
		warn("find_p2p_bridge failed (error code = 0x%x)\n", status);

	return 0;
}

static struct acpiphp_bridge *acpiphp_handle_to_bridge(acpi_handle handle)
{
	struct acpiphp_bridge *bridge;

	list_for_each_entry(bridge, &bridge_list, list)
		if (bridge->handle == handle)
			return bridge;

	return NULL;
}

static void cleanup_bridge(struct acpiphp_bridge *bridge)
{
	struct acpiphp_slot *slot, *next;
	struct acpiphp_func *func, *tmp;
	acpi_status status;
	acpi_handle handle = bridge->handle;

	status = acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
					    handle_hotplug_event_bridge);
	if (ACPI_FAILURE(status))
		err("failed to remove notify handler\n");

	if ((bridge->type != BRIDGE_TYPE_HOST) &&
	    ((bridge->flags & BRIDGE_HAS_EJ0) && bridge->func)) {
		status = acpi_install_notify_handler(bridge->func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func,
						bridge->func);
		if (ACPI_FAILURE(status))
			err("failed to install interrupt notify handler\n");
	}

	slot = bridge->slots;
	while (slot) {
		next = slot->next;
		list_for_each_entry_safe(func, tmp, &slot->funcs, sibling) {
			if (is_dock_device(func->handle)) {
				unregister_hotplug_dock_device(func->handle);
				unregister_dock_notifier(&func->nb);
			}
			if (!(func->flags & FUNC_HAS_DCK)) {
				status = acpi_remove_notify_handler(func->handle,
						ACPI_SYSTEM_NOTIFY,
						handle_hotplug_event_func);
				if (ACPI_FAILURE(status))
					err("failed to remove notify handler\n");
			}
			list_del(&func->sibling);
			kfree(func);
		}
		acpiphp_unregister_hotplug_slot(slot);
		list_del(&slot->funcs);
		kfree(slot);
		slot = next;
	}

	/*
	 * Only P2P bridges have a pci_dev
	 */
	if (bridge->pci_dev)
		put_device(&bridge->pci_bus->dev);

	pci_dev_put(bridge->pci_dev);
	list_del(&bridge->list);
	kfree(bridge);
}

static acpi_status
cleanup_p2p_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	struct acpiphp_bridge *bridge;

	/* cleanup p2p bridges under this P2P bridge
	   in a depth-first manner */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, (u32)1,
				cleanup_p2p_bridge, NULL, NULL, NULL);

	bridge = acpiphp_handle_to_bridge(handle);
	if (bridge)
		cleanup_bridge(bridge);

	return AE_OK;
}

static void remove_bridge(struct acpi_pci_root *root)
{
	struct acpiphp_bridge *bridge;
	acpi_handle handle = root->device->handle;

	/* cleanup p2p bridges under this host bridge
	   in a depth-first manner */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
				(u32)1, cleanup_p2p_bridge, NULL, NULL, NULL);

	/*
	 * On root bridges with hotplug slots directly underneath (ie,
	 * no p2p bridge between), we call cleanup_bridge(). 
	 *
	 * The else clause cleans up root bridges that either had no
	 * hotplug slots at all, or had a p2p bridge underneath.
	 */
	bridge = acpiphp_handle_to_bridge(handle);
	if (bridge)
		cleanup_bridge(bridge);
	else
		acpi_remove_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
					   handle_hotplug_event_bridge);
}

static int power_on_slot(struct acpiphp_slot *slot)
{
	acpi_status status;
	struct acpiphp_func *func;
	int retval = 0;

	/* if already enabled, just skip */
	if (slot->flags & SLOT_POWEREDON)
		goto err_exit;

	list_for_each_entry(func, &slot->funcs, sibling) {
		if (func->flags & FUNC_HAS_PS0) {
			dbg("%s: executing _PS0\n", __func__);
			status = acpi_evaluate_object(func->handle, "_PS0", NULL, NULL);
			if (ACPI_FAILURE(status)) {
				warn("%s: _PS0 failed\n", __func__);
				retval = -1;
				goto err_exit;
			} else
				break;
		}
	}

	/* TBD: evaluate _STA to check if the slot is enabled */

	slot->flags |= SLOT_POWEREDON;

 err_exit:
	return retval;
}


static int power_off_slot(struct acpiphp_slot *slot)
{
	acpi_status status;
	struct acpiphp_func *func;

	int retval = 0;

	/* if already disabled, just skip */
	if ((slot->flags & SLOT_POWEREDON) == 0)
		goto err_exit;

	list_for_each_entry(func, &slot->funcs, sibling) {
		if (func->flags & FUNC_HAS_PS3) {
			status = acpi_evaluate_object(func->handle, "_PS3", NULL, NULL);
			if (ACPI_FAILURE(status)) {
				warn("%s: _PS3 failed\n", __func__);
				retval = -1;
				goto err_exit;
			} else
				break;
		}
	}

	/* TBD: evaluate _STA to check if the slot is disabled */

	slot->flags &= (~SLOT_POWEREDON);

 err_exit:
	return retval;
}



/**
 * acpiphp_max_busnr - return the highest reserved bus number under the given bus.
 * @bus: bus to start search with
 */
static unsigned char acpiphp_max_busnr(struct pci_bus *bus)
{
	struct list_head *tmp;
	unsigned char max, n;

	/*
	 * pci_bus_max_busnr will return the highest
	 * reserved busnr for all these children.
	 * that is equivalent to the bus->subordinate
	 * value.  We don't want to use the parent's
	 * bus->subordinate value because it could have
	 * padding in it.
	 */
	max = bus->busn_res.start;

	list_for_each(tmp, &bus->children) {
		n = pci_bus_max_busnr(pci_bus_b(tmp));
		if (n > max)
			max = n;
	}
	return max;
}


/**
 * acpiphp_bus_add - add a new bus to acpi subsystem
 * @func: acpiphp_func of the bridge
 */
static int acpiphp_bus_add(struct acpiphp_func *func)
{
	struct acpi_device *device;
	int ret_val;

	if (!acpi_bus_get_device(func->handle, &device)) {
		dbg("bus exists... trim\n");
		/* this shouldn't be in here, so remove
		 * the bus then re-add it...
		 */
		ret_val = acpi_bus_trim(device);
		dbg("acpi_bus_trim return %x\n", ret_val);
	}

	ret_val = acpi_bus_add(func->handle);
	if (!ret_val)
		ret_val = acpi_bus_get_device(func->handle, &device);

	if (ret_val)
		dbg("error adding bus, %x\n", -ret_val);

	return ret_val;
}


/**
 * acpiphp_bus_trim - trim a bus from acpi subsystem
 * @handle: handle to acpi namespace
 */
static int acpiphp_bus_trim(acpi_handle handle)
{
	struct acpi_device *device;
	int retval;

	retval = acpi_bus_get_device(handle, &device);
	if (retval) {
		dbg("acpi_device not found\n");
		return retval;
	}

	retval = acpi_bus_trim(device);
	if (retval)
		err("cannot remove from acpi list\n");

	return retval;
}

static void acpiphp_set_acpi_region(struct acpiphp_slot *slot)
{
	struct acpiphp_func *func;
	union acpi_object params[2];
	struct acpi_object_list arg_list;

	list_for_each_entry(func, &slot->funcs, sibling) {
		arg_list.count = 2;
		arg_list.pointer = params;
		params[0].type = ACPI_TYPE_INTEGER;
		params[0].integer.value = ACPI_ADR_SPACE_PCI_CONFIG;
		params[1].type = ACPI_TYPE_INTEGER;
		params[1].integer.value = 1;
		/* _REG is optional, we don't care about if there is failure */
		acpi_evaluate_object(func->handle, "_REG", &arg_list, NULL);
	}
}

/**
 * enable_device - enable, configure a slot
 * @slot: slot to be enabled
 *
 * This function should be called per *physical slot*,
 * not per each slot object in ACPI namespace.
 */
static int __ref enable_device(struct acpiphp_slot *slot)
{
	struct pci_dev *dev;
	struct pci_bus *bus = slot->bridge->pci_bus;
	struct acpiphp_func *func;
	int retval = 0;
	int num, max, pass;
	acpi_status status;

	if (slot->flags & SLOT_ENABLED)
		goto err_exit;

	num = pci_scan_slot(bus, PCI_DEVFN(slot->device, 0));
	if (num == 0) {
		/* Maybe only part of funcs are added. */
		dbg("No new device found\n");
		goto err_exit;
	}

	max = acpiphp_max_busnr(bus);
	for (pass = 0; pass < 2; pass++) {
		list_for_each_entry(dev, &bus->devices, bus_list) {
			if (PCI_SLOT(dev->devfn) != slot->device)
				continue;
			if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE ||
			    dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
				max = pci_scan_bridge(bus, dev, max, pass);
				if (pass && dev->subordinate)
					pci_bus_size_bridges(dev->subordinate);
			}
		}
	}

	list_for_each_entry(func, &slot->funcs, sibling)
		acpiphp_bus_add(func);

	pci_bus_assign_resources(bus);
	acpiphp_sanitize_bus(bus);
	acpiphp_set_hpp_values(bus);
	acpiphp_set_acpi_region(slot);
	pci_enable_bridges(bus);

	list_for_each_entry(dev, &bus->devices, bus_list) {
		/* Assume that newly added devices are powered on already. */
		if (!dev->is_added)
			dev->current_state = PCI_D0;
	}

	pci_bus_add_devices(bus);

	slot->flags |= SLOT_ENABLED;
	list_for_each_entry(func, &slot->funcs, sibling) {
		dev = pci_get_slot(bus, PCI_DEVFN(slot->device,
						  func->function));
		if (!dev) {
			/* Do not set SLOT_ENABLED flag if some funcs
			   are not added. */
			slot->flags &= (~SLOT_ENABLED);
			continue;
		}

		if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE &&
		    dev->hdr_type != PCI_HEADER_TYPE_CARDBUS) {
			pci_dev_put(dev);
			continue;
		}

		status = find_p2p_bridge(func->handle, (u32)1, bus, NULL);
		if (ACPI_FAILURE(status))
			warn("find_p2p_bridge failed (error code = 0x%x)\n",
				status);
		pci_dev_put(dev);
	}


 err_exit:
	return retval;
}

/* return first device in slot, acquiring a reference on it */
static struct pci_dev *dev_in_slot(struct acpiphp_slot *slot)
{
	struct pci_bus *bus = slot->bridge->pci_bus;
	struct pci_dev *dev;
	struct pci_dev *ret = NULL;

	down_read(&pci_bus_sem);
	list_for_each_entry(dev, &bus->devices, bus_list)
		if (PCI_SLOT(dev->devfn) == slot->device) {
			ret = pci_dev_get(dev);
			break;
		}
	up_read(&pci_bus_sem);

	return ret;
}

/**
 * disable_device - disable a slot
 * @slot: ACPI PHP slot
 */
static int disable_device(struct acpiphp_slot *slot)
{
	struct acpiphp_func *func;
	struct pci_dev *pdev;
	struct pci_bus *bus = slot->bridge->pci_bus;

	/* The slot will be enabled when func 0 is added, so check
	   func 0 before disable the slot. */
	pdev = pci_get_slot(bus, PCI_DEVFN(slot->device, 0));
	if (!pdev)
		goto err_exit;
	pci_dev_put(pdev);

	list_for_each_entry(func, &slot->funcs, sibling) {
		if (func->bridge) {
			/* cleanup p2p bridges under this P2P bridge */
			cleanup_p2p_bridge(func->bridge->handle,
						(u32)1, NULL, NULL);
			func->bridge = NULL;
		}
	}

	/*
	 * enable_device() enumerates all functions in this device via
	 * pci_scan_slot(), whether they have associated ACPI hotplug
	 * methods (_EJ0, etc.) or not.  Therefore, we remove all functions
	 * here.
	 */
	while ((pdev = dev_in_slot(slot))) {
		pci_stop_and_remove_bus_device(pdev);
		pci_dev_put(pdev);
	}

	list_for_each_entry(func, &slot->funcs, sibling) {
		acpiphp_bus_trim(func->handle);
	}

	slot->flags &= (~SLOT_ENABLED);

err_exit:
	return 0;
}


/**
 * get_slot_status - get ACPI slot status
 * @slot: ACPI PHP slot
 *
 * If a slot has _STA for each function and if any one of them
 * returned non-zero status, return it.
 *
 * If a slot doesn't have _STA and if any one of its functions'
 * configuration space is configured, return 0x0f as a _STA.
 *
 * Otherwise return 0.
 */
static unsigned int get_slot_status(struct acpiphp_slot *slot)
{
	acpi_status status;
	unsigned long long sta = 0;
	u32 dvid;
	struct acpiphp_func *func;

	list_for_each_entry(func, &slot->funcs, sibling) {
		if (func->flags & FUNC_HAS_STA) {
			status = acpi_evaluate_integer(func->handle, "_STA", NULL, &sta);
			if (ACPI_SUCCESS(status) && sta)
				break;
		} else {
			pci_bus_read_config_dword(slot->bridge->pci_bus,
						  PCI_DEVFN(slot->device,
							    func->function),
						  PCI_VENDOR_ID, &dvid);
			if (dvid != 0xffffffff) {
				sta = ACPI_STA_ALL;
				break;
			}
		}
	}

	return (unsigned int)sta;
}

/**
 * acpiphp_eject_slot - physically eject the slot
 * @slot: ACPI PHP slot
 */
int acpiphp_eject_slot(struct acpiphp_slot *slot)
{
	acpi_status status;
	struct acpiphp_func *func;
	struct acpi_object_list arg_list;
	union acpi_object arg;

	list_for_each_entry(func, &slot->funcs, sibling) {
		/* We don't want to call _EJ0 on non-existing functions. */
		if ((func->flags & FUNC_HAS_EJ0)) {
			/* _EJ0 method take one argument */
			arg_list.count = 1;
			arg_list.pointer = &arg;
			arg.type = ACPI_TYPE_INTEGER;
			arg.integer.value = 1;

			status = acpi_evaluate_object(func->handle, "_EJ0", &arg_list, NULL);
			if (ACPI_FAILURE(status)) {
				warn("%s: _EJ0 failed\n", __func__);
				return -1;
			} else
				break;
		}
	}
	return 0;
}

/**
 * acpiphp_check_bridge - re-enumerate devices
 * @bridge: where to begin re-enumeration
 *
 * Iterate over all slots under this bridge and make sure that if a
 * card is present they are enabled, and if not they are disabled.
 */
static int acpiphp_check_bridge(struct acpiphp_bridge *bridge)
{
	struct acpiphp_slot *slot;
	int retval = 0;
	int enabled, disabled;

	enabled = disabled = 0;

	for (slot = bridge->slots; slot; slot = slot->next) {
		unsigned int status = get_slot_status(slot);
		if (slot->flags & SLOT_ENABLED) {
			if (status == ACPI_STA_ALL)
				continue;
			retval = acpiphp_disable_slot(slot);
			if (retval) {
				err("Error occurred in disabling\n");
				goto err_exit;
			} else {
				acpiphp_eject_slot(slot);
			}
			disabled++;
		} else {
			if (status != ACPI_STA_ALL)
				continue;
			retval = acpiphp_enable_slot(slot);
			if (retval) {
				err("Error occurred in enabling\n");
				goto err_exit;
			}
			enabled++;
		}
	}

	dbg("%s: %d enabled, %d disabled\n", __func__, enabled, disabled);

 err_exit:
	return retval;
}

static void acpiphp_set_hpp_values(struct pci_bus *bus)
{
	struct pci_dev *dev;

	list_for_each_entry(dev, &bus->devices, bus_list)
		pci_configure_slot(dev);
}

/*
 * Remove devices for which we could not assign resources, call
 * arch specific code to fix-up the bus
 */
static void acpiphp_sanitize_bus(struct pci_bus *bus)
{
	struct pci_dev *dev;
	int i;
	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM;

	list_for_each_entry(dev, &bus->devices, bus_list) {
		for (i=0; i<PCI_BRIDGE_RESOURCES; i++) {
			struct resource *res = &dev->resource[i];
			if ((res->flags & type_mask) && !res->start &&
					res->end) {
				/* Could not assign a required resources
				 * for this device, remove it */
				pci_stop_and_remove_bus_device(dev);
				break;
			}
		}
	}
}

/* Program resources in newly inserted bridge */
static int acpiphp_configure_bridge (acpi_handle handle)
{
	struct pci_bus *bus;

	if (acpi_is_root_bridge(handle)) {
		struct acpi_pci_root *root = acpi_pci_find_root(handle);
		bus = root->bus;
	} else {
		struct pci_dev *pdev = acpi_get_pci_dev(handle);
		bus = pdev->subordinate;
		pci_dev_put(pdev);
	}

	pci_bus_size_bridges(bus);
	pci_bus_assign_resources(bus);
	acpiphp_sanitize_bus(bus);
	acpiphp_set_hpp_values(bus);
	pci_enable_bridges(bus);
	return 0;
}

static void handle_bridge_insertion(acpi_handle handle, u32 type)
{
	struct acpi_device *device;

	if ((type != ACPI_NOTIFY_BUS_CHECK) &&
			(type != ACPI_NOTIFY_DEVICE_CHECK)) {
		err("unexpected notification type %d\n", type);
		return;
	}

	if (acpi_bus_add(handle)) {
		err("cannot add bridge to acpi list\n");
		return;
	}
	if (acpi_bus_get_device(handle, &device)) {
		err("ACPI device object missing\n");
		return;
	}
	if (!acpiphp_configure_bridge(handle))
		add_bridge(handle);
	else
		err("cannot configure and start bridge\n");

}

/*
 * ACPI event handlers
 */

static acpi_status
count_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = (int *)context;
	struct acpiphp_bridge *bridge;

	bridge = acpiphp_handle_to_bridge(handle);
	if (bridge)
		(*count)++;
	return AE_OK ;
}

static acpi_status
check_sub_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	struct acpiphp_bridge *bridge;
	char objname[64];
	struct acpi_buffer buffer = { .length = sizeof(objname),
				      .pointer = objname };

	bridge = acpiphp_handle_to_bridge(handle);
	if (bridge) {
		acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
		dbg("%s: re-enumerating slots under %s\n",
			__func__, objname);
		acpiphp_check_bridge(bridge);
	}
	return AE_OK ;
}

struct acpiphp_hp_work {
	struct work_struct work;
	acpi_handle handle;
	u32 type;
	void *context;
};

static void alloc_acpiphp_hp_work(acpi_handle handle, u32 type,
				  void *context,
				  void (*func)(struct work_struct *work))
{
	struct acpiphp_hp_work *hp_work;
	int ret;

	hp_work = kmalloc(sizeof(*hp_work), GFP_KERNEL);
	if (!hp_work)
		return;

	hp_work->handle = handle;
	hp_work->type = type;
	hp_work->context = context;

	INIT_WORK(&hp_work->work, func);
	ret = queue_work(kacpi_hotplug_wq, &hp_work->work);
	if (!ret)
		kfree(hp_work);
}

static void _handle_hotplug_event_bridge(struct work_struct *work)
{
	struct acpiphp_bridge *bridge;
	char objname[64];
	struct acpi_buffer buffer = { .length = sizeof(objname),
				      .pointer = objname };
	struct acpi_device *device;
	int num_sub_bridges = 0;
	struct acpiphp_hp_work *hp_work;
	acpi_handle handle;
	u32 type;

	hp_work = container_of(work, struct acpiphp_hp_work, work);
	handle = hp_work->handle;
	type = hp_work->type;

	if (acpi_bus_get_device(handle, &device)) {
		/* This bridge must have just been physically inserted */
		handle_bridge_insertion(handle, type);
		goto out;
	}

	bridge = acpiphp_handle_to_bridge(handle);
	if (type == ACPI_NOTIFY_BUS_CHECK) {
		acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, ACPI_UINT32_MAX,
			count_sub_bridges, NULL, &num_sub_bridges, NULL);
	}

	if (!bridge && !num_sub_bridges) {
		err("cannot get bridge info\n");
		goto out;
	}

	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

	switch (type) {
	case ACPI_NOTIFY_BUS_CHECK:
		/* bus re-enumerate */
		dbg("%s: Bus check notify on %s\n", __func__, objname);
		if (bridge) {
			dbg("%s: re-enumerating slots under %s\n",
				__func__, objname);
			acpiphp_check_bridge(bridge);
		}
		if (num_sub_bridges)
			acpi_walk_namespace(ACPI_TYPE_DEVICE, handle,
				ACPI_UINT32_MAX, check_sub_bridges, NULL, NULL, NULL);
		break;

	case ACPI_NOTIFY_DEVICE_CHECK:
		/* device check */
		dbg("%s: Device check notify on %s\n", __func__, objname);
		acpiphp_check_bridge(bridge);
		break;

	case ACPI_NOTIFY_DEVICE_WAKE:
		/* wake event */
		dbg("%s: Device wake notify on %s\n", __func__, objname);
		break;

	case ACPI_NOTIFY_EJECT_REQUEST:
		/* request device eject */
		dbg("%s: Device eject notify on %s\n", __func__, objname);
		if ((bridge->type != BRIDGE_TYPE_HOST) &&
		    (bridge->flags & BRIDGE_HAS_EJ0)) {
			struct acpiphp_slot *slot;
			slot = bridge->func->slot;
			if (!acpiphp_disable_slot(slot))
				acpiphp_eject_slot(slot);
		}
		break;

	case ACPI_NOTIFY_FREQUENCY_MISMATCH:
		printk(KERN_ERR "Device %s cannot be configured due"
				" to a frequency mismatch\n", objname);
		break;

	case ACPI_NOTIFY_BUS_MODE_MISMATCH:
		printk(KERN_ERR "Device %s cannot be configured due"
				" to a bus mode mismatch\n", objname);
		break;

	case ACPI_NOTIFY_POWER_FAULT:
		printk(KERN_ERR "Device %s has suffered a power fault\n",
				objname);
		break;

	default:
		warn("notify_handler: unknown event type 0x%x for %s\n", type, objname);
		break;
	}

out:
	kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
}

/**
 * handle_hotplug_event_bridge - handle ACPI event on bridges
 * @handle: Notify()'ed acpi_handle
 * @type: Notify code
 * @context: pointer to acpiphp_bridge structure
 *
 * Handles ACPI event notification on {host,p2p} bridges.
 */
static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,
					void *context)
{
	/*
	 * Currently the code adds all hotplug events to the kacpid_wq
	 * queue when it should add hotplug events to the kacpi_hotplug_wq.
	 * The proper way to fix this is to reorganize the code so that
	 * drivers (dock, etc.) do not call acpi_os_execute(), etc.
	 * For now just re-add this work to the kacpi_hotplug_wq so we
	 * don't deadlock on hotplug actions.
	 */
	alloc_acpiphp_hp_work(handle, type, context,
			      _handle_hotplug_event_bridge);
}

static void _handle_hotplug_event_func(struct work_struct *work)
{
	struct acpiphp_func *func;
	char objname[64];
	struct acpi_buffer buffer = { .length = sizeof(objname),
				      .pointer = objname };
	struct acpiphp_hp_work *hp_work;
	acpi_handle handle;
	u32 type;
	void *context;

	hp_work = container_of(work, struct acpiphp_hp_work, work);
	handle = hp_work->handle;
	type = hp_work->type;
	context = hp_work->context;

	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);

	func = (struct acpiphp_func *)context;

	switch (type) {
	case ACPI_NOTIFY_BUS_CHECK:
		/* bus re-enumerate */
		dbg("%s: Bus check notify on %s\n", __func__, objname);
		acpiphp_enable_slot(func->slot);
		break;

	case ACPI_NOTIFY_DEVICE_CHECK:
		/* device check : re-enumerate from parent bus */
		dbg("%s: Device check notify on %s\n", __func__, objname);
		acpiphp_check_bridge(func->slot->bridge);
		break;

	case ACPI_NOTIFY_DEVICE_WAKE:
		/* wake event */
		dbg("%s: Device wake notify on %s\n", __func__, objname);
		break;

	case ACPI_NOTIFY_EJECT_REQUEST:
		/* request device eject */
		dbg("%s: Device eject notify on %s\n", __func__, objname);
		if (!(acpiphp_disable_slot(func->slot)))
			acpiphp_eject_slot(func->slot);
		break;

	default:
		warn("notify_handler: unknown event type 0x%x for %s\n", type, objname);
		break;
	}

	kfree(hp_work); /* allocated in handle_hotplug_event_func */
}

/**
 * handle_hotplug_event_func - handle ACPI event on functions (i.e. slots)
 * @handle: Notify()'ed acpi_handle
 * @type: Notify code
 * @context: pointer to acpiphp_func structure
 *
 * Handles ACPI event notification on slots.
 */
static void handle_hotplug_event_func(acpi_handle handle, u32 type,
				      void *context)
{
	/*
	 * Currently the code adds all hotplug events to the kacpid_wq
	 * queue when it should add hotplug events to the kacpi_hotplug_wq.
	 * The proper way to fix this is to reorganize the code so that
	 * drivers (dock, etc.) do not call acpi_os_execute(), etc.
	 * For now just re-add this work to the kacpi_hotplug_wq so we
	 * don't deadlock on hotplug actions.
	 */
	alloc_acpiphp_hp_work(handle, type, context,
			      _handle_hotplug_event_func);
}

static acpi_status
find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
{
	int *count = (int *)context;

	if (!acpi_is_root_bridge(handle))
		return AE_OK;

	(*count)++;
	acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
				    handle_hotplug_event_bridge, NULL);

	return AE_OK ;
}

static struct acpi_pci_driver acpi_pci_hp_driver = {
	.add =		add_bridge,
	.remove =	remove_bridge,
};

/**
 * acpiphp_glue_init - initializes all PCI hotplug - ACPI glue data structures
 */
int __init acpiphp_glue_init(void)
{
	int num = 0;

	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
			ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);

	if (num <= 0)
		return -1;
	else
		acpi_pci_register_driver(&acpi_pci_hp_driver);

	return 0;
}


/**
 * acpiphp_glue_exit - terminates all PCI hotplug - ACPI glue data structures
 *
 * This function frees all data allocated in acpiphp_glue_init().
 */
void  acpiphp_glue_exit(void)
{
	acpi_pci_unregister_driver(&acpi_pci_hp_driver);
}


/**
 * acpiphp_get_num_slots - count number of slots in a system
 */
int __init acpiphp_get_num_slots(void)
{
	struct acpiphp_bridge *bridge;
	int num_slots = 0;

	list_for_each_entry(bridge, &bridge_list, list) {
		dbg("Bus %04x:%02x has %d slot%s\n",
				pci_domain_nr(bridge->pci_bus),
				bridge->pci_bus->number, bridge->nr_slots,
				bridge->nr_slots == 1 ? "" : "s");
		num_slots += bridge->nr_slots;
	}

	dbg("Total %d slots\n", num_slots);
	return num_slots;
}


/**
 * acpiphp_enable_slot - power on slot
 * @slot: ACPI PHP slot
 */
int acpiphp_enable_slot(struct acpiphp_slot *slot)
{
	int retval;

	mutex_lock(&slot->crit_sect);

	/* wake up all functions */
	retval = power_on_slot(slot);
	if (retval)
		goto err_exit;

	if (get_slot_status(slot) == ACPI_STA_ALL) {
		/* configure all functions */
		retval = enable_device(slot);
		if (retval)
			power_off_slot(slot);
	} else {
		dbg("%s: Slot status is not ACPI_STA_ALL\n", __func__);
		power_off_slot(slot);
	}

 err_exit:
	mutex_unlock(&slot->crit_sect);
	return retval;
}

/**
 * acpiphp_disable_slot - power off slot
 * @slot: ACPI PHP slot
 */
int acpiphp_disable_slot(struct acpiphp_slot *slot)
{
	int retval = 0;

	mutex_lock(&slot->crit_sect);

	/* unconfigure all functions */
	retval = disable_device(slot);
	if (retval)
		goto err_exit;

	/* power off all functions */
	retval = power_off_slot(slot);
	if (retval)
		goto err_exit;

 err_exit:
	mutex_unlock(&slot->crit_sect);
	return retval;
}


/*
 * slot enabled:  1
 * slot disabled: 0
 */
u8 acpiphp_get_power_status(struct acpiphp_slot *slot)
{
	return (slot->flags & SLOT_POWEREDON);
}


/*
 * latch   open:  1
 * latch closed:  0
 */
u8 acpiphp_get_latch_status(struct acpiphp_slot *slot)
{
	unsigned int sta;

	sta = get_slot_status(slot);

	return (sta & ACPI_STA_SHOW_IN_UI) ? 0 : 1;
}


/*
 * adapter presence : 1
 *          absence : 0
 */
u8 acpiphp_get_adapter_status(struct acpiphp_slot *slot)
{
	unsigned int sta;

	sta = get_slot_status(slot);

	return (sta == 0) ? 0 : 1;
}