summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/psci/psci.c
blob: 2328ca58bba61fdb677ac20a1a7447882cd0cf22 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright (C) 2015 ARM Limited
 */

#define pr_fmt(fmt) "psci: " fmt

#include <linux/acpi.h>
#include <linux/arm-smccc.h>
#include <linux/cpuidle.h>
#include <linux/debugfs.h>
#include <linux/errno.h>
#include <linux/linkage.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/printk.h>
#include <linux/psci.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/suspend.h>

#include <uapi/linux/psci.h>

#include <asm/cpuidle.h>
#include <asm/cputype.h>
#include <asm/hypervisor.h>
#include <asm/system_misc.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>

/*
 * While a 64-bit OS can make calls with SMC32 calling conventions, for some
 * calls it is necessary to use SMC64 to pass or return 64-bit values.
 * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
 * (native-width) function ID.
 */
#ifdef CONFIG_64BIT
#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
#else
#define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
#endif

/*
 * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
 * calls to its resident CPU, so we must avoid issuing those. We never migrate
 * a Trusted OS even if it claims to be capable of migration -- doing so will
 * require cooperation with a Trusted OS driver.
 */
static int resident_cpu = -1;
struct psci_operations psci_ops;
static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;

bool psci_tos_resident_on(int cpu)
{
	return cpu == resident_cpu;
}

typedef unsigned long (psci_fn)(unsigned long, unsigned long,
				unsigned long, unsigned long);
static psci_fn *invoke_psci_fn;

static struct psci_0_1_function_ids psci_0_1_function_ids;

struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
{
	return psci_0_1_function_ids;
}

#define PSCI_0_2_POWER_STATE_MASK		\
				(PSCI_0_2_POWER_STATE_ID_MASK | \
				PSCI_0_2_POWER_STATE_TYPE_MASK | \
				PSCI_0_2_POWER_STATE_AFFL_MASK)

#define PSCI_1_0_EXT_POWER_STATE_MASK		\
				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)

static u32 psci_cpu_suspend_feature;
static bool psci_system_reset2_supported;

static inline bool psci_has_ext_power_state(void)
{
	return psci_cpu_suspend_feature &
				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
}

bool psci_has_osi_support(void)
{
	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
}

static inline bool psci_power_state_loses_context(u32 state)
{
	const u32 mask = psci_has_ext_power_state() ?
					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
					PSCI_0_2_POWER_STATE_TYPE_MASK;

	return state & mask;
}

bool psci_power_state_is_valid(u32 state)
{
	const u32 valid_mask = psci_has_ext_power_state() ?
			       PSCI_1_0_EXT_POWER_STATE_MASK :
			       PSCI_0_2_POWER_STATE_MASK;

	return !(state & ~valid_mask);
}

static __always_inline unsigned long
__invoke_psci_fn_hvc(unsigned long function_id,
		     unsigned long arg0, unsigned long arg1,
		     unsigned long arg2)
{
	struct arm_smccc_res res;

	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
	return res.a0;
}

static __always_inline unsigned long
__invoke_psci_fn_smc(unsigned long function_id,
		     unsigned long arg0, unsigned long arg1,
		     unsigned long arg2)
{
	struct arm_smccc_res res;

	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
	return res.a0;
}

static __always_inline int psci_to_linux_errno(int errno)
{
	switch (errno) {
	case PSCI_RET_SUCCESS:
		return 0;
	case PSCI_RET_NOT_SUPPORTED:
		return -EOPNOTSUPP;
	case PSCI_RET_INVALID_PARAMS:
	case PSCI_RET_INVALID_ADDRESS:
		return -EINVAL;
	case PSCI_RET_DENIED:
		return -EPERM;
	}

	return -EINVAL;
}

static u32 psci_0_1_get_version(void)
{
	return PSCI_VERSION(0, 1);
}

static u32 psci_0_2_get_version(void)
{
	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
}

int psci_set_osi_mode(bool enable)
{
	unsigned long suspend_mode;
	int err;

	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
			PSCI_1_0_SUSPEND_MODE_PC;

	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
	if (err < 0)
		pr_info(FW_BUG "failed to set %s mode: %d\n",
				enable ? "OSI" : "PC", err);
	return psci_to_linux_errno(err);
}

static __always_inline int
__psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
{
	int err;

	err = invoke_psci_fn(fn, state, entry_point, 0);
	return psci_to_linux_errno(err);
}

static __always_inline int
psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
{
	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
				  state, entry_point);
}

static __always_inline int
psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
{
	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
				  state, entry_point);
}

static int __psci_cpu_off(u32 fn, u32 state)
{
	int err;

	err = invoke_psci_fn(fn, state, 0, 0);
	return psci_to_linux_errno(err);
}

static int psci_0_1_cpu_off(u32 state)
{
	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
}

static int psci_0_2_cpu_off(u32 state)
{
	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
}

static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
{
	int err;

	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
	return psci_to_linux_errno(err);
}

static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
{
	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
}

static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
{
	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
}

static int __psci_migrate(u32 fn, unsigned long cpuid)
{
	int err;

	err = invoke_psci_fn(fn, cpuid, 0, 0);
	return psci_to_linux_errno(err);
}

static int psci_0_1_migrate(unsigned long cpuid)
{
	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
}

static int psci_0_2_migrate(unsigned long cpuid)
{
	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
}

static int psci_affinity_info(unsigned long target_affinity,
		unsigned long lowest_affinity_level)
{
	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
			      target_affinity, lowest_affinity_level, 0);
}

static int psci_migrate_info_type(void)
{
	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
}

static unsigned long psci_migrate_info_up_cpu(void)
{
	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
			      0, 0, 0);
}

static void set_conduit(enum arm_smccc_conduit conduit)
{
	switch (conduit) {
	case SMCCC_CONDUIT_HVC:
		invoke_psci_fn = __invoke_psci_fn_hvc;
		break;
	case SMCCC_CONDUIT_SMC:
		invoke_psci_fn = __invoke_psci_fn_smc;
		break;
	default:
		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
	}

	psci_conduit = conduit;
}

static int get_set_conduit_method(const struct device_node *np)
{
	const char *method;

	pr_info("probing for conduit method from DT.\n");

	if (of_property_read_string(np, "method", &method)) {
		pr_warn("missing \"method\" property\n");
		return -ENXIO;
	}

	if (!strcmp("hvc", method)) {
		set_conduit(SMCCC_CONDUIT_HVC);
	} else if (!strcmp("smc", method)) {
		set_conduit(SMCCC_CONDUIT_SMC);
	} else {
		pr_warn("invalid \"method\" property: %s\n", method);
		return -EINVAL;
	}
	return 0;
}

static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
			  void *data)
{
	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
	    psci_system_reset2_supported) {
		/*
		 * reset_type[31] = 0 (architectural)
		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
		 * cookie = 0 (ignored by the implementation)
		 */
		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
	} else {
		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
	}

	return NOTIFY_DONE;
}

static struct notifier_block psci_sys_reset_nb = {
	.notifier_call = psci_sys_reset,
	.priority = 129,
};

static void psci_sys_poweroff(void)
{
	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
}

static int psci_features(u32 psci_func_id)
{
	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
			      psci_func_id, 0, 0);
}

#ifdef CONFIG_DEBUG_FS

#define PSCI_ID(ver, _name) \
	{ .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
#define PSCI_ID_NATIVE(ver, _name) \
	{ .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }

/* A table of all optional functions */
static const struct {
	u32 fn;
	const char *name;
} psci_fn_ids[] = {
	PSCI_ID_NATIVE(0_2, MIGRATE),
	PSCI_ID(0_2, MIGRATE_INFO_TYPE),
	PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
	PSCI_ID(1_0, CPU_FREEZE),
	PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
	PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
	PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
	PSCI_ID(1_0, SET_SUSPEND_MODE),
	PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
	PSCI_ID_NATIVE(1_0, STAT_COUNT),
	PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
	PSCI_ID(1_1, MEM_PROTECT),
	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
};

static int psci_debugfs_read(struct seq_file *s, void *data)
{
	int feature, type, i;
	u32 ver;

	ver = psci_ops.get_version();
	seq_printf(s, "PSCIv%d.%d\n",
		   PSCI_VERSION_MAJOR(ver),
		   PSCI_VERSION_MINOR(ver));

	/* PSCI_FEATURES is available only starting from 1.0 */
	if (PSCI_VERSION_MAJOR(ver) < 1)
		return 0;

	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
	if (feature != PSCI_RET_NOT_SUPPORTED) {
		ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
		seq_printf(s, "SMC Calling Convention v%d.%d\n",
			   PSCI_VERSION_MAJOR(ver),
			   PSCI_VERSION_MINOR(ver));
	} else {
		seq_puts(s, "SMC Calling Convention v1.0 is assumed\n");
	}

	feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
	if (feature < 0) {
		seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
	} else {
		seq_printf(s, "OSI is %ssupported\n",
			   (feature & BIT(0)) ? "" : "not ");
		seq_printf(s, "%s StateID format is used\n",
			   (feature & BIT(1)) ? "Extended" : "Original");
	}

	type = psci_ops.migrate_info_type();
	if (type == PSCI_0_2_TOS_UP_MIGRATE ||
	    type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
		unsigned long cpuid;

		seq_printf(s, "Trusted OS %smigrate capable\n",
			   type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
		cpuid = psci_migrate_info_up_cpu();
		seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n",
			   cpuid, resident_cpu);
	} else if (type == PSCI_0_2_TOS_MP) {
		seq_puts(s, "Trusted OS migration not required\n");
	} else {
		if (type != PSCI_RET_NOT_SUPPORTED)
			seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
	}

	for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
		feature = psci_features(psci_fn_ids[i].fn);
		if (feature == PSCI_RET_NOT_SUPPORTED)
			continue;
		if (feature < 0)
			seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n",
				   psci_fn_ids[i].name, feature);
		else
			seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
	}

	return 0;
}

static int psci_debugfs_open(struct inode *inode, struct file *f)
{
	return single_open(f, psci_debugfs_read, NULL);
}

static const struct file_operations psci_debugfs_ops = {
	.owner = THIS_MODULE,
	.open = psci_debugfs_open,
	.release = single_release,
	.read = seq_read,
	.llseek = seq_lseek
};

static int __init psci_debugfs_init(void)
{
	if (!invoke_psci_fn || !psci_ops.get_version)
		return 0;

	return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL,
						   &psci_debugfs_ops));
}
late_initcall(psci_debugfs_init)
#endif

#ifdef CONFIG_CPU_IDLE
static noinstr int psci_suspend_finisher(unsigned long state)
{
	u32 power_state = state;
	phys_addr_t pa_cpu_resume;

	pa_cpu_resume = __pa_symbol_nodebug((unsigned long)cpu_resume);

	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
}

int psci_cpu_suspend_enter(u32 state)
{
	int ret;

	if (!psci_power_state_loses_context(state)) {
		struct arm_cpuidle_irq_context context;

		ct_cpuidle_enter();
		arm_cpuidle_save_irq_context(&context);
		ret = psci_ops.cpu_suspend(state, 0);
		arm_cpuidle_restore_irq_context(&context);
		ct_cpuidle_exit();
	} else {
		/*
		 * ARM64 cpu_suspend() wants to do ct_cpuidle_*() itself.
		 */
		if (!IS_ENABLED(CONFIG_ARM64))
			ct_cpuidle_enter();

		ret = cpu_suspend(state, psci_suspend_finisher);

		if (!IS_ENABLED(CONFIG_ARM64))
			ct_cpuidle_exit();
	}

	return ret;
}
#endif

static int psci_system_suspend(unsigned long unused)
{
	int err;
	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);

	err = invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
			      pa_cpu_resume, 0, 0);
	return psci_to_linux_errno(err);
}

static int psci_system_suspend_enter(suspend_state_t state)
{
	return cpu_suspend(0, psci_system_suspend);
}

static const struct platform_suspend_ops psci_suspend_ops = {
	.valid          = suspend_valid_only_mem,
	.enter          = psci_system_suspend_enter,
};

static void __init psci_init_system_reset2(void)
{
	int ret;

	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));

	if (ret != PSCI_RET_NOT_SUPPORTED)
		psci_system_reset2_supported = true;
}

static void __init psci_init_system_suspend(void)
{
	int ret;

	if (!IS_ENABLED(CONFIG_SUSPEND))
		return;

	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));

	if (ret != PSCI_RET_NOT_SUPPORTED)
		suspend_set_ops(&psci_suspend_ops);
}

static void __init psci_init_cpu_suspend(void)
{
	int feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));

	if (feature != PSCI_RET_NOT_SUPPORTED)
		psci_cpu_suspend_feature = feature;
}

/*
 * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
 * return DENIED (which would be fatal).
 */
static void __init psci_init_migrate(void)
{
	unsigned long cpuid;
	int type, cpu = -1;

	type = psci_ops.migrate_info_type();

	if (type == PSCI_0_2_TOS_MP) {
		pr_info("Trusted OS migration not required\n");
		return;
	}

	if (type == PSCI_RET_NOT_SUPPORTED) {
		pr_info("MIGRATE_INFO_TYPE not supported.\n");
		return;
	}

	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
		return;
	}

	cpuid = psci_migrate_info_up_cpu();
	if (cpuid & ~MPIDR_HWID_BITMASK) {
		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
			cpuid);
		return;
	}

	cpu = get_logical_index(cpuid);
	resident_cpu = cpu >= 0 ? cpu : -1;

	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
}

static void __init psci_init_smccc(void)
{
	u32 ver = ARM_SMCCC_VERSION_1_0;
	int feature;

	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);

	if (feature != PSCI_RET_NOT_SUPPORTED) {
		u32 ret;
		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
		if (ret >= ARM_SMCCC_VERSION_1_1) {
			arm_smccc_version_init(ret, psci_conduit);
			ver = ret;
		}
	}

	/*
	 * Conveniently, the SMCCC and PSCI versions are encoded the
	 * same way. No, this isn't accidental.
	 */
	pr_info("SMC Calling Convention v%d.%d\n",
		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));

}

static void __init psci_0_2_set_functions(void)
{
	pr_info("Using standard PSCI v0.2 function IDs\n");

	psci_ops = (struct psci_operations){
		.get_version = psci_0_2_get_version,
		.cpu_suspend = psci_0_2_cpu_suspend,
		.cpu_off = psci_0_2_cpu_off,
		.cpu_on = psci_0_2_cpu_on,
		.migrate = psci_0_2_migrate,
		.affinity_info = psci_affinity_info,
		.migrate_info_type = psci_migrate_info_type,
	};

	register_restart_handler(&psci_sys_reset_nb);

	pm_power_off = psci_sys_poweroff;
}

/*
 * Probe function for PSCI firmware versions >= 0.2
 */
static int __init psci_probe(void)
{
	u32 ver = psci_0_2_get_version();

	pr_info("PSCIv%d.%d detected in firmware.\n",
			PSCI_VERSION_MAJOR(ver),
			PSCI_VERSION_MINOR(ver));

	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
		pr_err("Conflicting PSCI version detected.\n");
		return -EINVAL;
	}

	psci_0_2_set_functions();

	psci_init_migrate();

	if (PSCI_VERSION_MAJOR(ver) >= 1) {
		psci_init_smccc();
		psci_init_cpu_suspend();
		psci_init_system_suspend();
		psci_init_system_reset2();
		kvm_init_hyp_services();
	}

	return 0;
}

typedef int (*psci_initcall_t)(const struct device_node *);

/*
 * PSCI init function for PSCI versions >=0.2
 *
 * Probe based on PSCI PSCI_VERSION function
 */
static int __init psci_0_2_init(const struct device_node *np)
{
	int err;

	err = get_set_conduit_method(np);
	if (err)
		return err;

	/*
	 * Starting with v0.2, the PSCI specification introduced a call
	 * (PSCI_VERSION) that allows probing the firmware version, so
	 * that PSCI function IDs and version specific initialization
	 * can be carried out according to the specific version reported
	 * by firmware
	 */
	return psci_probe();
}

/*
 * PSCI < v0.2 get PSCI Function IDs via DT.
 */
static int __init psci_0_1_init(const struct device_node *np)
{
	u32 id;
	int err;

	err = get_set_conduit_method(np);
	if (err)
		return err;

	pr_info("Using PSCI v0.1 Function IDs from DT\n");

	psci_ops.get_version = psci_0_1_get_version;

	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
		psci_0_1_function_ids.cpu_suspend = id;
		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
	}

	if (!of_property_read_u32(np, "cpu_off", &id)) {
		psci_0_1_function_ids.cpu_off = id;
		psci_ops.cpu_off = psci_0_1_cpu_off;
	}

	if (!of_property_read_u32(np, "cpu_on", &id)) {
		psci_0_1_function_ids.cpu_on = id;
		psci_ops.cpu_on = psci_0_1_cpu_on;
	}

	if (!of_property_read_u32(np, "migrate", &id)) {
		psci_0_1_function_ids.migrate = id;
		psci_ops.migrate = psci_0_1_migrate;
	}

	return 0;
}

static int __init psci_1_0_init(const struct device_node *np)
{
	int err;

	err = psci_0_2_init(np);
	if (err)
		return err;

	if (psci_has_osi_support()) {
		pr_info("OSI mode supported.\n");

		/* Default to PC mode. */
		psci_set_osi_mode(false);
	}

	return 0;
}

static const struct of_device_id psci_of_match[] __initconst = {
	{ .compatible = "arm,psci",	.data = psci_0_1_init},
	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
	{},
};

int __init psci_dt_init(void)
{
	struct device_node *np;
	const struct of_device_id *matched_np;
	psci_initcall_t init_fn;
	int ret;

	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);

	if (!np || !of_device_is_available(np))
		return -ENODEV;

	init_fn = (psci_initcall_t)matched_np->data;
	ret = init_fn(np);

	of_node_put(np);
	return ret;
}

#ifdef CONFIG_ACPI
/*
 * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
 * explicitly clarified in SBBR
 */
int __init psci_acpi_init(void)
{
	if (!acpi_psci_present()) {
		pr_info("is not implemented in ACPI.\n");
		return -EOPNOTSUPP;
	}

	pr_info("probing for conduit method from ACPI.\n");

	if (acpi_psci_use_hvc())
		set_conduit(SMCCC_CONDUIT_HVC);
	else
		set_conduit(SMCCC_CONDUIT_SMC);

	return psci_probe();
}
#endif