summaryrefslogtreecommitdiffstats
path: root/drivers/acpi/pci_root.c
blob: 240544253ccdf276c3518d6e4cdabae45f0d0df6 (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
/*
 *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/pci.h>
#include <linux/pci-acpi.h>
#include <linux/pci-aspm.h>
#include <linux/dmar.h>
#include <linux/acpi.h>
#include <linux/slab.h>
#include <linux/dmi.h>
#include <acpi/apei.h>	/* for acpi_hest_init() */

#include "internal.h"

#define _COMPONENT		ACPI_PCI_COMPONENT
ACPI_MODULE_NAME("pci_root");
#define ACPI_PCI_ROOT_CLASS		"pci_bridge"
#define ACPI_PCI_ROOT_DEVICE_NAME	"PCI Root Bridge"
static int acpi_pci_root_add(struct acpi_device *device,
			     const struct acpi_device_id *not_used);
static void acpi_pci_root_remove(struct acpi_device *device);

static int acpi_pci_root_scan_dependent(struct acpi_device *adev)
{
	acpiphp_check_host_bridge(adev);
	return 0;
}

#define ACPI_PCIE_REQ_SUPPORT (OSC_PCI_EXT_CONFIG_SUPPORT \
				| OSC_PCI_ASPM_SUPPORT \
				| OSC_PCI_CLOCK_PM_SUPPORT \
				| OSC_PCI_MSI_SUPPORT)

static const struct acpi_device_id root_device_ids[] = {
	{"PNP0A03", 0},
	{"", 0},
};

static struct acpi_scan_handler pci_root_handler = {
	.ids = root_device_ids,
	.attach = acpi_pci_root_add,
	.detach = acpi_pci_root_remove,
	.hotplug = {
		.enabled = true,
		.scan_dependent = acpi_pci_root_scan_dependent,
	},
};

static DEFINE_MUTEX(osc_lock);

/**
 * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
 * @handle - the ACPI CA node in question.
 *
 * Note: we could make this API take a struct acpi_device * instead, but
 * for now, it's more convenient to operate on an acpi_handle.
 */
int acpi_is_root_bridge(acpi_handle handle)
{
	int ret;
	struct acpi_device *device;

	ret = acpi_bus_get_device(handle, &device);
	if (ret)
		return 0;

	ret = acpi_match_device_ids(device, root_device_ids);
	if (ret)
		return 0;
	else
		return 1;
}
EXPORT_SYMBOL_GPL(acpi_is_root_bridge);

static acpi_status
get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
{
	struct resource *res = data;
	struct acpi_resource_address64 address;
	acpi_status status;

	status = acpi_resource_to_address64(resource, &address);
	if (ACPI_FAILURE(status))
		return AE_OK;

	if ((address.address.address_length > 0) &&
	    (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
		res->start = address.address.minimum;
		res->end = address.address.minimum + address.address.address_length - 1;
	}

	return AE_OK;
}

static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
					     struct resource *res)
{
	acpi_status status;

	res->start = -1;
	status =
	    acpi_walk_resources(handle, METHOD_NAME__CRS,
				get_root_bridge_busnr_callback, res);
	if (ACPI_FAILURE(status))
		return status;
	if (res->start == -1)
		return AE_ERROR;
	return AE_OK;
}

struct pci_osc_bit_struct {
	u32 bit;
	char *desc;
};

static struct pci_osc_bit_struct pci_osc_support_bit[] = {
	{ OSC_PCI_EXT_CONFIG_SUPPORT, "ExtendedConfig" },
	{ OSC_PCI_ASPM_SUPPORT, "ASPM" },
	{ OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
	{ OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
	{ OSC_PCI_MSI_SUPPORT, "MSI" },
};

static struct pci_osc_bit_struct pci_osc_control_bit[] = {
	{ OSC_PCI_EXPRESS_NATIVE_HP_CONTROL, "PCIeHotplug" },
	{ OSC_PCI_SHPC_NATIVE_HP_CONTROL, "SHPCHotplug" },
	{ OSC_PCI_EXPRESS_PME_CONTROL, "PME" },
	{ OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
	{ OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
};

static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
			    struct pci_osc_bit_struct *table, int size)
{
	char buf[80];
	int i, len = 0;
	struct pci_osc_bit_struct *entry;

	buf[0] = '\0';
	for (i = 0, entry = table; i < size; i++, entry++)
		if (word & entry->bit)
			len += snprintf(buf + len, sizeof(buf) - len, "%s%s",
					len ? " " : "", entry->desc);

	dev_info(&root->device->dev, "_OSC: %s [%s]\n", msg, buf);
}

static void decode_osc_support(struct acpi_pci_root *root, char *msg, u32 word)
{
	decode_osc_bits(root, msg, word, pci_osc_support_bit,
			ARRAY_SIZE(pci_osc_support_bit));
}

static void decode_osc_control(struct acpi_pci_root *root, char *msg, u32 word)
{
	decode_osc_bits(root, msg, word, pci_osc_control_bit,
			ARRAY_SIZE(pci_osc_control_bit));
}

static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";

static acpi_status acpi_pci_run_osc(acpi_handle handle,
				    const u32 *capbuf, u32 *retval)
{
	struct acpi_osc_context context = {
		.uuid_str = pci_osc_uuid_str,
		.rev = 1,
		.cap.length = 12,
		.cap.pointer = (void *)capbuf,
	};
	acpi_status status;

	status = acpi_run_osc(handle, &context);
	if (ACPI_SUCCESS(status)) {
		*retval = *((u32 *)(context.ret.pointer + 8));
		kfree(context.ret.pointer);
	}
	return status;
}

static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
					u32 support,
					u32 *control)
{
	acpi_status status;
	u32 result, capbuf[3];

	support &= OSC_PCI_SUPPORT_MASKS;
	support |= root->osc_support_set;

	capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;
	capbuf[OSC_SUPPORT_DWORD] = support;
	if (control) {
		*control &= OSC_PCI_CONTROL_MASKS;
		capbuf[OSC_CONTROL_DWORD] = *control | root->osc_control_set;
	} else {
		/* Run _OSC query only with existing controls. */
		capbuf[OSC_CONTROL_DWORD] = root->osc_control_set;
	}

	status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
	if (ACPI_SUCCESS(status)) {
		root->osc_support_set = support;
		if (control)
			*control = result;
	}
	return status;
}

static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
{
	acpi_status status;

	mutex_lock(&osc_lock);
	status = acpi_pci_query_osc(root, flags, NULL);
	mutex_unlock(&osc_lock);
	return status;
}

struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
{
	struct acpi_pci_root *root;
	struct acpi_device *device;

	if (acpi_bus_get_device(handle, &device) ||
	    acpi_match_device_ids(device, root_device_ids))
		return NULL;

	root = acpi_driver_data(device);

	return root;
}
EXPORT_SYMBOL_GPL(acpi_pci_find_root);

struct acpi_handle_node {
	struct list_head node;
	acpi_handle handle;
};

/**
 * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 * @handle: the handle in question
 *
 * Given an ACPI CA handle, the desired PCI device is located in the
 * list of PCI devices.
 *
 * If the device is found, its reference count is increased and this
 * function returns a pointer to its data structure.  The caller must
 * decrement the reference count by calling pci_dev_put().
 * If no device is found, %NULL is returned.
 */
struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
{
	int dev, fn;
	unsigned long long adr;
	acpi_status status;
	acpi_handle phandle;
	struct pci_bus *pbus;
	struct pci_dev *pdev = NULL;
	struct acpi_handle_node *node, *tmp;
	struct acpi_pci_root *root;
	LIST_HEAD(device_list);

	/*
	 * Walk up the ACPI CA namespace until we reach a PCI root bridge.
	 */
	phandle = handle;
	while (!acpi_is_root_bridge(phandle)) {
		node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
		if (!node)
			goto out;

		INIT_LIST_HEAD(&node->node);
		node->handle = phandle;
		list_add(&node->node, &device_list);

		status = acpi_get_parent(phandle, &phandle);
		if (ACPI_FAILURE(status))
			goto out;
	}

	root = acpi_pci_find_root(phandle);
	if (!root)
		goto out;

	pbus = root->bus;

	/*
	 * Now, walk back down the PCI device tree until we return to our
	 * original handle. Assumes that everything between the PCI root
	 * bridge and the device we're looking for must be a P2P bridge.
	 */
	list_for_each_entry(node, &device_list, node) {
		acpi_handle hnd = node->handle;
		status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
		if (ACPI_FAILURE(status))
			goto out;
		dev = (adr >> 16) & 0xffff;
		fn  = adr & 0xffff;

		pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
		if (!pdev || hnd == handle)
			break;

		pbus = pdev->subordinate;
		pci_dev_put(pdev);

		/*
		 * This function may be called for a non-PCI device that has a
		 * PCI parent (eg. a disk under a PCI SATA controller).  In that
		 * case pdev->subordinate will be NULL for the parent.
		 */
		if (!pbus) {
			dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
			pdev = NULL;
			break;
		}
	}
out:
	list_for_each_entry_safe(node, tmp, &device_list, node)
		kfree(node);

	return pdev;
}
EXPORT_SYMBOL_GPL(acpi_get_pci_dev);

/**
 * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
 * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
 * @mask: Mask of _OSC bits to request control of, place to store control mask.
 * @req: Mask of _OSC bits the control of is essential to the caller.
 *
 * Run _OSC query for @mask and if that is successful, compare the returned
 * mask of control bits with @req.  If all of the @req bits are set in the
 * returned mask, run _OSC request for it.
 *
 * The variable at the @mask address may be modified regardless of whether or
 * not the function returns success.  On success it will contain the mask of
 * _OSC bits the BIOS has granted control of, but its contents are meaningless
 * on failure.
 **/
acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
{
	struct acpi_pci_root *root;
	acpi_status status = AE_OK;
	u32 ctrl, capbuf[3];

	if (!mask)
		return AE_BAD_PARAMETER;

	ctrl = *mask & OSC_PCI_CONTROL_MASKS;
	if ((ctrl & req) != req)
		return AE_TYPE;

	root = acpi_pci_find_root(handle);
	if (!root)
		return AE_NOT_EXIST;

	mutex_lock(&osc_lock);

	*mask = ctrl | root->osc_control_set;
	/* No need to evaluate _OSC if the control was already granted. */
	if ((root->osc_control_set & ctrl) == ctrl)
		goto out;

	/* Need to check the available controls bits before requesting them. */
	while (*mask) {
		status = acpi_pci_query_osc(root, root->osc_support_set, mask);
		if (ACPI_FAILURE(status))
			goto out;
		if (ctrl == *mask)
			break;
		decode_osc_control(root, "platform does not support",
				   ctrl & ~(*mask));
		ctrl = *mask;
	}

	if ((ctrl & req) != req) {
		decode_osc_control(root, "not requesting control; platform does not support",
				   req & ~(ctrl));
		status = AE_SUPPORT;
		goto out;
	}

	capbuf[OSC_QUERY_DWORD] = 0;
	capbuf[OSC_SUPPORT_DWORD] = root->osc_support_set;
	capbuf[OSC_CONTROL_DWORD] = ctrl;
	status = acpi_pci_run_osc(handle, capbuf, mask);
	if (ACPI_SUCCESS(status))
		root->osc_control_set = *mask;
out:
	mutex_unlock(&osc_lock);
	return status;
}
EXPORT_SYMBOL(acpi_pci_osc_control_set);

static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
{
	u32 support, control, requested;
	acpi_status status;
	struct acpi_device *device = root->device;
	acpi_handle handle = device->handle;

	/*
	 * Apple always return failure on _OSC calls when _OSI("Darwin") has
	 * been called successfully. We know the feature set supported by the
	 * platform, so avoid calling _OSC at all
	 */

	if (dmi_match(DMI_SYS_VENDOR, "Apple Inc.")) {
		root->osc_control_set = ~OSC_PCI_EXPRESS_PME_CONTROL;
		decode_osc_control(root, "OS assumes control of",
				   root->osc_control_set);
		return;
	}

	/*
	 * All supported architectures that use ACPI have support for
	 * PCI domains, so we indicate this in _OSC support capabilities.
	 */
	support = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
	if (pci_ext_cfg_avail())
		support |= OSC_PCI_EXT_CONFIG_SUPPORT;
	if (pcie_aspm_support_enabled())
		support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
	if (pci_msi_enabled())
		support |= OSC_PCI_MSI_SUPPORT;

	decode_osc_support(root, "OS supports", support);
	status = acpi_pci_osc_support(root, support);
	if (ACPI_FAILURE(status)) {
		dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
			 acpi_format_exception(status));
		*no_aspm = 1;
		return;
	}

	if (pcie_ports_disabled) {
		dev_info(&device->dev, "PCIe port services disabled; not requesting _OSC control\n");
		return;
	}

	if ((support & ACPI_PCIE_REQ_SUPPORT) != ACPI_PCIE_REQ_SUPPORT) {
		decode_osc_support(root, "not requesting OS control; OS requires",
				   ACPI_PCIE_REQ_SUPPORT);
		return;
	}

	control = OSC_PCI_EXPRESS_CAPABILITY_CONTROL
		| OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
		| OSC_PCI_EXPRESS_PME_CONTROL;

	if (pci_aer_available()) {
		if (aer_acpi_firmware_first())
			dev_info(&device->dev,
				 "PCIe AER handled by firmware\n");
		else
			control |= OSC_PCI_EXPRESS_AER_CONTROL;
	}

	requested = control;
	status = acpi_pci_osc_control_set(handle, &control,
					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
	if (ACPI_SUCCESS(status)) {
		decode_osc_control(root, "OS now controls", control);
		if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
			/*
			 * We have ASPM control, but the FADT indicates that
			 * it's unsupported. Leave existing configuration
			 * intact and prevent the OS from touching it.
			 */
			dev_info(&device->dev, "FADT indicates ASPM is unsupported, using BIOS configuration\n");
			*no_aspm = 1;
		}
	} else {
		decode_osc_control(root, "OS requested", requested);
		decode_osc_control(root, "platform willing to grant", control);
		dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
			acpi_format_exception(status));

		/*
		 * We want to disable ASPM here, but aspm_disabled
		 * needs to remain in its state from boot so that we
		 * properly handle PCIe 1.1 devices.  So we set this
		 * flag here, to defer the action until after the ACPI
		 * root scan.
		 */
		*no_aspm = 1;
	}
}

static int acpi_pci_root_add(struct acpi_device *device,
			     const struct acpi_device_id *not_used)
{
	unsigned long long segment, bus;
	acpi_status status;
	int result;
	struct acpi_pci_root *root;
	acpi_handle handle = device->handle;
	int no_aspm = 0;
	bool hotadd = system_state == SYSTEM_RUNNING;

	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
	if (!root)
		return -ENOMEM;

	segment = 0;
	status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL,
				       &segment);
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
		dev_err(&device->dev,  "can't evaluate _SEG\n");
		result = -ENODEV;
		goto end;
	}

	/* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
	root->secondary.flags = IORESOURCE_BUS;
	status = try_get_root_bridge_busnr(handle, &root->secondary);
	if (ACPI_FAILURE(status)) {
		/*
		 * We need both the start and end of the downstream bus range
		 * to interpret _CBA (MMCONFIG base address), so it really is
		 * supposed to be in _CRS.  If we don't find it there, all we
		 * can do is assume [_BBN-0xFF] or [0-0xFF].
		 */
		root->secondary.end = 0xFF;
		dev_warn(&device->dev,
			 FW_BUG "no secondary bus range in _CRS\n");
		status = acpi_evaluate_integer(handle, METHOD_NAME__BBN,
					       NULL, &bus);
		if (ACPI_SUCCESS(status))
			root->secondary.start = bus;
		else if (status == AE_NOT_FOUND)
			root->secondary.start = 0;
		else {
			dev_err(&device->dev, "can't evaluate _BBN\n");
			result = -ENODEV;
			goto end;
		}
	}

	root->device = device;
	root->segment = segment & 0xFFFF;
	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
	device->driver_data = root;

	if (hotadd && dmar_device_add(handle)) {
		result = -ENXIO;
		goto end;
	}

	pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
	       acpi_device_name(device), acpi_device_bid(device),
	       root->segment, &root->secondary);

	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);

	negotiate_os_control(root, &no_aspm);

	/*
	 * TBD: Need PCI interface for enumeration/configuration of roots.
	 */

	/*
	 * Scan the Root Bridge
	 * --------------------
	 * Must do this prior to any attempt to bind the root device, as the
	 * PCI namespace does not get created until this call is made (and
	 * thus the root bridge's pci_dev does not exist).
	 */
	root->bus = pci_acpi_scan_root(root);
	if (!root->bus) {
		dev_err(&device->dev,
			"Bus %04x:%02x not present in PCI namespace\n",
			root->segment, (unsigned int)root->secondary.start);
		device->driver_data = NULL;
		result = -ENODEV;
		goto remove_dmar;
	}

	if (no_aspm)
		pcie_no_aspm();

	pci_acpi_add_bus_pm_notifier(device);
	if (device->wakeup.flags.run_wake)
		device_set_run_wake(root->bus->bridge, true);

	if (hotadd) {
		pcibios_resource_survey_bus(root->bus);
		pci_assign_unassigned_root_bus_resources(root->bus);
		/*
		 * This is only called for the hotadd case. For the boot-time
		 * case, we need to wait until after PCI initialization in
		 * order to deal with IOAPICs mapped in on a PCI BAR.
		 *
		 * This is currently x86-specific, because acpi_ioapic_add()
		 * is an empty function without CONFIG_ACPI_HOTPLUG_IOAPIC.
		 * And CONFIG_ACPI_HOTPLUG_IOAPIC depends on CONFIG_X86_IO_APIC
		 * (see drivers/acpi/Kconfig).
		 */
		acpi_ioapic_add(root->device->handle);
	}

	pci_lock_rescan_remove();
	pci_bus_add_devices(root->bus);
	pci_unlock_rescan_remove();
	return 1;

remove_dmar:
	if (hotadd)
		dmar_device_remove(handle);
end:
	kfree(root);
	return result;
}

static void acpi_pci_root_remove(struct acpi_device *device)
{
	struct acpi_pci_root *root = acpi_driver_data(device);

	pci_lock_rescan_remove();

	pci_stop_root_bus(root->bus);

	pci_ioapic_remove(root);
	device_set_run_wake(root->bus->bridge, false);
	pci_acpi_remove_bus_pm_notifier(device);

	pci_remove_root_bus(root->bus);
	WARN_ON(acpi_ioapic_remove(root));

	dmar_device_remove(device->handle);

	pci_unlock_rescan_remove();

	kfree(root);
}

/*
 * Following code to support acpi_pci_root_create() is copied from
 * arch/x86/pci/acpi.c and modified so it could be reused by x86, IA64
 * and ARM64.
 */
static void acpi_pci_root_validate_resources(struct device *dev,
					     struct list_head *resources,
					     unsigned long type)
{
	LIST_HEAD(list);
	struct resource *res1, *res2, *root = NULL;
	struct resource_entry *tmp, *entry, *entry2;

	BUG_ON((type & (IORESOURCE_MEM | IORESOURCE_IO)) == 0);
	root = (type & IORESOURCE_MEM) ? &iomem_resource : &ioport_resource;

	list_splice_init(resources, &list);
	resource_list_for_each_entry_safe(entry, tmp, &list) {
		bool free = false;
		resource_size_t end;

		res1 = entry->res;
		if (!(res1->flags & type))
			goto next;

		/* Exclude non-addressable range or non-addressable portion */
		end = min(res1->end, root->end);
		if (end <= res1->start) {
			dev_info(dev, "host bridge window %pR (ignored, not CPU addressable)\n",
				 res1);
			free = true;
			goto next;
		} else if (res1->end != end) {
			dev_info(dev, "host bridge window %pR ([%#llx-%#llx] ignored, not CPU addressable)\n",
				 res1, (unsigned long long)end + 1,
				 (unsigned long long)res1->end);
			res1->end = end;
		}

		resource_list_for_each_entry(entry2, resources) {
			res2 = entry2->res;
			if (!(res2->flags & type))
				continue;

			/*
			 * I don't like throwing away windows because then
			 * our resources no longer match the ACPI _CRS, but
			 * the kernel resource tree doesn't allow overlaps.
			 */
			if (resource_overlaps(res1, res2)) {
				res2->start = min(res1->start, res2->start);
				res2->end = max(res1->end, res2->end);
				dev_info(dev, "host bridge window expanded to %pR; %pR ignored\n",
					 res2, res1);
				free = true;
				goto next;
			}
		}

next:
		resource_list_del(entry);
		if (free)
			resource_list_free_entry(entry);
		else
			resource_list_add_tail(entry, resources);
	}
}

static void acpi_pci_root_remap_iospace(struct resource_entry *entry)
{
#ifdef PCI_IOBASE
	struct resource *res = entry->res;
	resource_size_t cpu_addr = res->start;
	resource_size_t pci_addr = cpu_addr - entry->offset;
	resource_size_t length = resource_size(res);
	unsigned long port;

	if (pci_register_io_range(cpu_addr, length))
		goto err;

	port = pci_address_to_pio(cpu_addr);
	if (port == (unsigned long)-1)
		goto err;

	res->start = port;
	res->end = port + length - 1;
	entry->offset = port - pci_addr;

	if (pci_remap_iospace(res, cpu_addr) < 0)
		goto err;

	pr_info("Remapped I/O %pa to %pR\n", &cpu_addr, res);
	return;
err:
	res->flags |= IORESOURCE_DISABLED;
#endif
}

int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
{
	int ret;
	struct list_head *list = &info->resources;
	struct acpi_device *device = info->bridge;
	struct resource_entry *entry, *tmp;
	unsigned long flags;

	flags = IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_MEM_8AND16BIT;
	ret = acpi_dev_get_resources(device, list,
				     acpi_dev_filter_resource_type_cb,
				     (void *)flags);
	if (ret < 0)
		dev_warn(&device->dev,
			 "failed to parse _CRS method, error code %d\n", ret);
	else if (ret == 0)
		dev_dbg(&device->dev,
			"no IO and memory resources present in _CRS\n");
	else {
		resource_list_for_each_entry_safe(entry, tmp, list) {
			if (entry->res->flags & IORESOURCE_IO)
				acpi_pci_root_remap_iospace(entry);

			if (entry->res->flags & IORESOURCE_DISABLED)
				resource_list_destroy_entry(entry);
			else
				entry->res->name = info->name;
		}
		acpi_pci_root_validate_resources(&device->dev, list,
						 IORESOURCE_MEM);
		acpi_pci_root_validate_resources(&device->dev, list,
						 IORESOURCE_IO);
	}

	return ret;
}

static void pci_acpi_root_add_resources(struct acpi_pci_root_info *info)
{
	struct resource_entry *entry, *tmp;
	struct resource *res, *conflict, *root = NULL;

	resource_list_for_each_entry_safe(entry, tmp, &info->resources) {
		res = entry->res;
		if (res->flags & IORESOURCE_MEM)
			root = &iomem_resource;
		else if (res->flags & IORESOURCE_IO)
			root = &ioport_resource;
		else
			continue;

		/*
		 * Some legacy x86 host bridge drivers use iomem_resource and
		 * ioport_resource as default resource pool, skip it.
		 */
		if (res == root)
			continue;

		conflict = insert_resource_conflict(root, res);
		if (conflict) {
			dev_info(&info->bridge->dev,
				 "ignoring host bridge window %pR (conflicts with %s %pR)\n",
				 res, conflict->name, conflict);
			resource_list_destroy_entry(entry);
		}
	}
}

static void __acpi_pci_root_release_info(struct acpi_pci_root_info *info)
{
	struct resource *res;
	struct resource_entry *entry, *tmp;

	if (!info)
		return;

	resource_list_for_each_entry_safe(entry, tmp, &info->resources) {
		res = entry->res;
		if (res->parent &&
		    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
			release_resource(res);
		resource_list_destroy_entry(entry);
	}

	info->ops->release_info(info);
}

static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)
{
	struct resource *res;
	struct resource_entry *entry;

	resource_list_for_each_entry(entry, &bridge->windows) {
		res = entry->res;
		if (res->flags & IORESOURCE_IO)
			pci_unmap_iospace(res);
		if (res->parent &&
		    (res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
			release_resource(res);
	}
	__acpi_pci_root_release_info(bridge->release_data);
}

struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
				     struct acpi_pci_root_ops *ops,
				     struct acpi_pci_root_info *info,
				     void *sysdata)
{
	int ret, busnum = root->secondary.start;
	struct acpi_device *device = root->device;
	int node = acpi_get_node(device->handle);
	struct pci_bus *bus;

	info->root = root;
	info->bridge = device;
	info->ops = ops;
	INIT_LIST_HEAD(&info->resources);
	snprintf(info->name, sizeof(info->name), "PCI Bus %04x:%02x",
		 root->segment, busnum);

	if (ops->init_info && ops->init_info(info))
		goto out_release_info;
	if (ops->prepare_resources)
		ret = ops->prepare_resources(info);
	else
		ret = acpi_pci_probe_root_resources(info);
	if (ret < 0)
		goto out_release_info;

	pci_acpi_root_add_resources(info);
	pci_add_resource(&info->resources, &root->secondary);
	bus = pci_create_root_bus(NULL, busnum, ops->pci_ops,
				  sysdata, &info->resources);
	if (!bus)
		goto out_release_info;

	pci_scan_child_bus(bus);
	pci_set_host_bridge_release(to_pci_host_bridge(bus->bridge),
				    acpi_pci_root_release_info, info);
	if (node != NUMA_NO_NODE)
		dev_printk(KERN_DEBUG, &bus->dev, "on NUMA node %d\n", node);
	return bus;

out_release_info:
	__acpi_pci_root_release_info(info);
	return NULL;
}

void __init acpi_pci_root_init(void)
{
	acpi_hest_init();
	if (acpi_pci_disabled)
		return;

	pci_acpi_crs_quirks();
	acpi_scan_add_handler_with_hotplug(&pci_root_handler, "pci_root");
}