aboutsummaryrefslogtreecommitdiff
path: root/arch/arm64/kernel/psci.c
blob: 869f202748e8eac758ce09440f0fa6e3b626b987 (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
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * Copyright (C) 2013 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 */

#define pr_fmt(fmt) "psci: " fmt

#include <linux/init.h>
#include <linux/of.h>
#include <linux/smp.h>
#include <linux/reboot.h>
#include <linux/pm.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <uapi/linux/psci.h>

#include <asm/compiler.h>
#include <asm/cputype.h>
#include <asm/cpu_ops.h>
#include <asm/errno.h>
#include <asm/psci.h>
#include <asm/smp_plat.h>
#include <asm/suspend.h>
#include <asm/system_misc.h>

#define PSCI_POWER_STATE_TYPE_STANDBY		0
#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1

static bool psci_power_state_loses_context(u32 state)
{
	return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
}

static bool psci_power_state_is_valid(u32 state)
{
	const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
			       PSCI_0_2_POWER_STATE_TYPE_MASK |
			       PSCI_0_2_POWER_STATE_AFFL_MASK;

	return !(state & ~valid_mask);
}

/*
 * 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 {
	int (*cpu_suspend)(u32 state, unsigned long entry_point);
	int (*cpu_off)(u32 state);
	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
	int (*migrate)(unsigned long cpuid);
	int (*affinity_info)(unsigned long target_affinity,
			unsigned long lowest_affinity_level);
	int (*migrate_info_type)(void);
};

static struct psci_operations psci_ops;

typedef unsigned long (psci_fn)(unsigned long, unsigned long,
				unsigned long, unsigned long);
asmlinkage psci_fn __invoke_psci_fn_hvc;
asmlinkage psci_fn __invoke_psci_fn_smc;
static psci_fn *invoke_psci_fn;

enum psci_function {
	PSCI_FN_CPU_SUSPEND,
	PSCI_FN_CPU_ON,
	PSCI_FN_CPU_OFF,
	PSCI_FN_MIGRATE,
	PSCI_FN_MAX,
};

static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);

static u32 psci_function_id[PSCI_FN_MAX];

static 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:
		return -EINVAL;
	case PSCI_RET_DENIED:
		return -EPERM;
	};

	return -EINVAL;
}

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

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

	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
	err = invoke_psci_fn(fn, state, entry_point, 0);
	return psci_to_linux_errno(err);
}

static int psci_cpu_off(u32 state)
{
	int err;
	u32 fn;

	fn = psci_function_id[PSCI_FN_CPU_OFF];
	err = invoke_psci_fn(fn, state, 0, 0);
	return psci_to_linux_errno(err);
}

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

	fn = psci_function_id[PSCI_FN_CPU_ON];
	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
	return psci_to_linux_errno(err);
}

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

	fn = psci_function_id[PSCI_FN_MIGRATE];
	err = invoke_psci_fn(fn, cpuid, 0, 0);
	return psci_to_linux_errno(err);
}

static int psci_affinity_info(unsigned long target_affinity,
		unsigned long lowest_affinity_level)
{
	return invoke_psci_fn(PSCI_0_2_FN64_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_0_2_FN64_MIGRATE_INFO_UP_CPU, 0, 0, 0);
}

static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
{
	int i, ret, count = 0;
	u32 *psci_states;
	struct device_node *state_node, *cpu_node;

	cpu_node = of_get_cpu_node(cpu, NULL);
	if (!cpu_node)
		return -ENODEV;

	/*
	 * If the PSCI cpu_suspend function hook has not been initialized
	 * idle states must not be enabled, so bail out
	 */
	if (!psci_ops.cpu_suspend)
		return -EOPNOTSUPP;

	/* Count idle states */
	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
					      count))) {
		count++;
		of_node_put(state_node);
	}

	if (!count)
		return -ENODEV;

	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
	if (!psci_states)
		return -ENOMEM;

	for (i = 0; i < count; i++) {
		u32 state;

		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);

		ret = of_property_read_u32(state_node,
					   "arm,psci-suspend-param",
					   &state);
		if (ret) {
			pr_warn(" * %s missing arm,psci-suspend-param property\n",
				state_node->full_name);
			of_node_put(state_node);
			goto free_mem;
		}

		of_node_put(state_node);
		pr_debug("psci-power-state %#x index %d\n", state, i);
		if (!psci_power_state_is_valid(state)) {
			pr_warn("Invalid PSCI power state %#x\n", state);
			ret = -EINVAL;
			goto free_mem;
		}
		psci_states[i] = state;
	}
	/* Idle states parsed correctly, initialize per-cpu pointer */
	per_cpu(psci_power_state, cpu) = psci_states;
	return 0;

free_mem:
	kfree(psci_states);
	return ret;
}

static int get_set_conduit_method(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)) {
		invoke_psci_fn = __invoke_psci_fn_hvc;
	} else if (!strcmp("smc", method)) {
		invoke_psci_fn = __invoke_psci_fn_smc;
	} else {
		pr_warn("invalid \"method\" property: %s\n", method);
		return -EINVAL;
	}
	return 0;
}

static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
{
	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
}

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

/*
 * 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;

	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_0_2_set_functions(void)
{
	pr_info("Using standard PSCI v0.2 function IDs\n");
	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
	psci_ops.cpu_suspend = psci_cpu_suspend;

	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
	psci_ops.cpu_off = psci_cpu_off;

	psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
	psci_ops.cpu_on = psci_cpu_on;

	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
	psci_ops.migrate = psci_migrate;

	psci_ops.affinity_info = psci_affinity_info;

	psci_ops.migrate_info_type = psci_migrate_info_type;

	arm_pm_restart = psci_sys_reset;

	pm_power_off = psci_sys_poweroff;
}

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

	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(struct device_node *np)
{
	int err;

	err = get_set_conduit_method(np);

	if (err)
		goto out_put_node;
	/*
	 * 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
	 */
	err = psci_probe();

out_put_node:
	of_node_put(np);
	return err;
}

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

	err = get_set_conduit_method(np);

	if (err)
		goto out_put_node;

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

	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
		psci_ops.cpu_suspend = psci_cpu_suspend;
	}

	if (!of_property_read_u32(np, "cpu_off", &id)) {
		psci_function_id[PSCI_FN_CPU_OFF] = id;
		psci_ops.cpu_off = psci_cpu_off;
	}

	if (!of_property_read_u32(np, "cpu_on", &id)) {
		psci_function_id[PSCI_FN_CPU_ON] = id;
		psci_ops.cpu_on = psci_cpu_on;
	}

	if (!of_property_read_u32(np, "migrate", &id)) {
		psci_function_id[PSCI_FN_MIGRATE] = id;
		psci_ops.migrate = psci_migrate;
	}

out_put_node:
	of_node_put(np);
	return err;
}

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},
	{},
};

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

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

	if (!np)
		return -ENODEV;

	init_fn = (psci_initcall_t)matched_np->data;
	return init_fn(np);
}

#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())
		invoke_psci_fn = __invoke_psci_fn_hvc;
	else
		invoke_psci_fn = __invoke_psci_fn_smc;

	return psci_probe();
}
#endif

#ifdef CONFIG_SMP

static int __init cpu_psci_cpu_init(unsigned int cpu)
{
	return 0;
}

static int __init cpu_psci_cpu_prepare(unsigned int cpu)
{
	if (!psci_ops.cpu_on) {
		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
		return -ENODEV;
	}

	return 0;
}

static int cpu_psci_cpu_boot(unsigned int cpu)
{
	int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
	if (err)
		pr_err("failed to boot CPU%d (%d)\n", cpu, err);

	return err;
}

#ifdef CONFIG_HOTPLUG_CPU
static bool psci_tos_resident_on(int cpu)
{
	return cpu == resident_cpu;
}

static int cpu_psci_cpu_disable(unsigned int cpu)
{
	/* Fail early if we don't have CPU_OFF support */
	if (!psci_ops.cpu_off)
		return -EOPNOTSUPP;

	/* Trusted OS will deny CPU_OFF */
	if (psci_tos_resident_on(cpu))
		return -EPERM;

	return 0;
}

static void cpu_psci_cpu_die(unsigned int cpu)
{
	int ret;
	/*
	 * There are no known implementations of PSCI actually using the
	 * power state field, pass a sensible default for now.
	 */
	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;

	ret = psci_ops.cpu_off(state);

	pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
}

static int cpu_psci_cpu_kill(unsigned int cpu)
{
	int err, i;

	if (!psci_ops.affinity_info)
		return 0;
	/*
	 * cpu_kill could race with cpu_die and we can
	 * potentially end up declaring this cpu undead
	 * while it is dying. So, try again a few times.
	 */

	for (i = 0; i < 10; i++) {
		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
			pr_info("CPU%d killed.\n", cpu);
			return 0;
		}

		msleep(10);
		pr_info("Retrying again to check for CPU kill\n");
	}

	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
			cpu, err);
	return -ETIMEDOUT;
}
#endif
#endif

static int psci_suspend_finisher(unsigned long index)
{
	u32 *state = __this_cpu_read(psci_power_state);

	return psci_ops.cpu_suspend(state[index - 1],
				    virt_to_phys(cpu_resume));
}

static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
{
	int ret;
	u32 *state = __this_cpu_read(psci_power_state);
	/*
	 * idle state index 0 corresponds to wfi, should never be called
	 * from the cpu_suspend operations
	 */
	if (WARN_ON_ONCE(!index))
		return -EINVAL;

	if (!psci_power_state_loses_context(state[index - 1]))
		ret = psci_ops.cpu_suspend(state[index - 1], 0);
	else
		ret = cpu_suspend(index, psci_suspend_finisher);

	return ret;
}

const struct cpu_operations cpu_psci_ops = {
	.name		= "psci",
#ifdef CONFIG_CPU_IDLE
	.cpu_init_idle	= cpu_psci_cpu_init_idle,
	.cpu_suspend	= cpu_psci_cpu_suspend,
#endif
#ifdef CONFIG_SMP
	.cpu_init	= cpu_psci_cpu_init,
	.cpu_prepare	= cpu_psci_cpu_prepare,
	.cpu_boot	= cpu_psci_cpu_boot,
#ifdef CONFIG_HOTPLUG_CPU
	.cpu_disable	= cpu_psci_cpu_disable,
	.cpu_die	= cpu_psci_cpu_die,
	.cpu_kill	= cpu_psci_cpu_kill,
#endif
#endif
};