xref: /openbmc/linux/drivers/firmware/psci/psci.c (revision d6fc9fcb) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright (C) 2015 ARM Limited
5  */
6 
7 #define pr_fmt(fmt) "psci: " fmt
8 
9 #include <linux/acpi.h>
10 #include <linux/arm-smccc.h>
11 #include <linux/cpuidle.h>
12 #include <linux/errno.h>
13 #include <linux/linkage.h>
14 #include <linux/of.h>
15 #include <linux/pm.h>
16 #include <linux/printk.h>
17 #include <linux/psci.h>
18 #include <linux/reboot.h>
19 #include <linux/slab.h>
20 #include <linux/suspend.h>
21 
22 #include <uapi/linux/psci.h>
23 
24 #include <asm/cpuidle.h>
25 #include <asm/cputype.h>
26 #include <asm/system_misc.h>
27 #include <asm/smp_plat.h>
28 #include <asm/suspend.h>
29 
30 /*
31  * While a 64-bit OS can make calls with SMC32 calling conventions, for some
32  * calls it is necessary to use SMC64 to pass or return 64-bit values.
33  * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
34  * (native-width) function ID.
35  */
36 #ifdef CONFIG_64BIT
37 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
38 #else
39 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
40 #endif
41 
42 /*
43  * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
44  * calls to its resident CPU, so we must avoid issuing those. We never migrate
45  * a Trusted OS even if it claims to be capable of migration -- doing so will
46  * require cooperation with a Trusted OS driver.
47  */
48 static int resident_cpu = -1;
49 
50 bool psci_tos_resident_on(int cpu)
51 {
52 	return cpu == resident_cpu;
53 }
54 
55 struct psci_operations psci_ops = {
56 	.conduit = PSCI_CONDUIT_NONE,
57 	.smccc_version = SMCCC_VERSION_1_0,
58 };
59 
60 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
61 				unsigned long, unsigned long);
62 static psci_fn *invoke_psci_fn;
63 
64 enum psci_function {
65 	PSCI_FN_CPU_SUSPEND,
66 	PSCI_FN_CPU_ON,
67 	PSCI_FN_CPU_OFF,
68 	PSCI_FN_MIGRATE,
69 	PSCI_FN_MAX,
70 };
71 
72 static u32 psci_function_id[PSCI_FN_MAX];
73 
74 #define PSCI_0_2_POWER_STATE_MASK		\
75 				(PSCI_0_2_POWER_STATE_ID_MASK | \
76 				PSCI_0_2_POWER_STATE_TYPE_MASK | \
77 				PSCI_0_2_POWER_STATE_AFFL_MASK)
78 
79 #define PSCI_1_0_EXT_POWER_STATE_MASK		\
80 				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
81 				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)
82 
83 static u32 psci_cpu_suspend_feature;
84 static bool psci_system_reset2_supported;
85 
86 static inline bool psci_has_ext_power_state(void)
87 {
88 	return psci_cpu_suspend_feature &
89 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
90 }
91 
92 static inline bool psci_has_osi_support(void)
93 {
94 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
95 }
96 
97 static inline bool psci_power_state_loses_context(u32 state)
98 {
99 	const u32 mask = psci_has_ext_power_state() ?
100 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
101 					PSCI_0_2_POWER_STATE_TYPE_MASK;
102 
103 	return state & mask;
104 }
105 
106 static inline bool psci_power_state_is_valid(u32 state)
107 {
108 	const u32 valid_mask = psci_has_ext_power_state() ?
109 			       PSCI_1_0_EXT_POWER_STATE_MASK :
110 			       PSCI_0_2_POWER_STATE_MASK;
111 
112 	return !(state & ~valid_mask);
113 }
114 
115 static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
116 			unsigned long arg0, unsigned long arg1,
117 			unsigned long arg2)
118 {
119 	struct arm_smccc_res res;
120 
121 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
122 	return res.a0;
123 }
124 
125 static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
126 			unsigned long arg0, unsigned long arg1,
127 			unsigned long arg2)
128 {
129 	struct arm_smccc_res res;
130 
131 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
132 	return res.a0;
133 }
134 
135 static int psci_to_linux_errno(int errno)
136 {
137 	switch (errno) {
138 	case PSCI_RET_SUCCESS:
139 		return 0;
140 	case PSCI_RET_NOT_SUPPORTED:
141 		return -EOPNOTSUPP;
142 	case PSCI_RET_INVALID_PARAMS:
143 	case PSCI_RET_INVALID_ADDRESS:
144 		return -EINVAL;
145 	case PSCI_RET_DENIED:
146 		return -EPERM;
147 	};
148 
149 	return -EINVAL;
150 }
151 
152 static u32 psci_get_version(void)
153 {
154 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
155 }
156 
157 static int psci_cpu_suspend(u32 state, unsigned long entry_point)
158 {
159 	int err;
160 	u32 fn;
161 
162 	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
163 	err = invoke_psci_fn(fn, state, entry_point, 0);
164 	return psci_to_linux_errno(err);
165 }
166 
167 static int psci_cpu_off(u32 state)
168 {
169 	int err;
170 	u32 fn;
171 
172 	fn = psci_function_id[PSCI_FN_CPU_OFF];
173 	err = invoke_psci_fn(fn, state, 0, 0);
174 	return psci_to_linux_errno(err);
175 }
176 
177 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
178 {
179 	int err;
180 	u32 fn;
181 
182 	fn = psci_function_id[PSCI_FN_CPU_ON];
183 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
184 	return psci_to_linux_errno(err);
185 }
186 
187 static int psci_migrate(unsigned long cpuid)
188 {
189 	int err;
190 	u32 fn;
191 
192 	fn = psci_function_id[PSCI_FN_MIGRATE];
193 	err = invoke_psci_fn(fn, cpuid, 0, 0);
194 	return psci_to_linux_errno(err);
195 }
196 
197 static int psci_affinity_info(unsigned long target_affinity,
198 		unsigned long lowest_affinity_level)
199 {
200 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
201 			      target_affinity, lowest_affinity_level, 0);
202 }
203 
204 static int psci_migrate_info_type(void)
205 {
206 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
207 }
208 
209 static unsigned long psci_migrate_info_up_cpu(void)
210 {
211 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
212 			      0, 0, 0);
213 }
214 
215 static void set_conduit(enum psci_conduit conduit)
216 {
217 	switch (conduit) {
218 	case PSCI_CONDUIT_HVC:
219 		invoke_psci_fn = __invoke_psci_fn_hvc;
220 		break;
221 	case PSCI_CONDUIT_SMC:
222 		invoke_psci_fn = __invoke_psci_fn_smc;
223 		break;
224 	default:
225 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
226 	}
227 
228 	psci_ops.conduit = conduit;
229 }
230 
231 static int get_set_conduit_method(struct device_node *np)
232 {
233 	const char *method;
234 
235 	pr_info("probing for conduit method from DT.\n");
236 
237 	if (of_property_read_string(np, "method", &method)) {
238 		pr_warn("missing \"method\" property\n");
239 		return -ENXIO;
240 	}
241 
242 	if (!strcmp("hvc", method)) {
243 		set_conduit(PSCI_CONDUIT_HVC);
244 	} else if (!strcmp("smc", method)) {
245 		set_conduit(PSCI_CONDUIT_SMC);
246 	} else {
247 		pr_warn("invalid \"method\" property: %s\n", method);
248 		return -EINVAL;
249 	}
250 	return 0;
251 }
252 
253 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
254 {
255 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
256 	    psci_system_reset2_supported) {
257 		/*
258 		 * reset_type[31] = 0 (architectural)
259 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
260 		 * cookie = 0 (ignored by the implementation)
261 		 */
262 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
263 	} else {
264 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
265 	}
266 }
267 
268 static void psci_sys_poweroff(void)
269 {
270 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
271 }
272 
273 static int __init psci_features(u32 psci_func_id)
274 {
275 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
276 			      psci_func_id, 0, 0);
277 }
278 
279 #ifdef CONFIG_CPU_IDLE
280 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
281 
282 static int psci_dt_parse_state_node(struct device_node *np, u32 *state)
283 {
284 	int err = of_property_read_u32(np, "arm,psci-suspend-param", state);
285 
286 	if (err) {
287 		pr_warn("%pOF missing arm,psci-suspend-param property\n", np);
288 		return err;
289 	}
290 
291 	if (!psci_power_state_is_valid(*state)) {
292 		pr_warn("Invalid PSCI power state %#x\n", *state);
293 		return -EINVAL;
294 	}
295 
296 	return 0;
297 }
298 
299 static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
300 {
301 	int i, ret = 0, count = 0;
302 	u32 *psci_states;
303 	struct device_node *state_node;
304 
305 	/* Count idle states */
306 	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
307 					      count))) {
308 		count++;
309 		of_node_put(state_node);
310 	}
311 
312 	if (!count)
313 		return -ENODEV;
314 
315 	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
316 	if (!psci_states)
317 		return -ENOMEM;
318 
319 	for (i = 0; i < count; i++) {
320 		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
321 		ret = psci_dt_parse_state_node(state_node, &psci_states[i]);
322 		of_node_put(state_node);
323 
324 		if (ret)
325 			goto free_mem;
326 
327 		pr_debug("psci-power-state %#x index %d\n", psci_states[i], i);
328 	}
329 
330 	/* Idle states parsed correctly, initialize per-cpu pointer */
331 	per_cpu(psci_power_state, cpu) = psci_states;
332 	return 0;
333 
334 free_mem:
335 	kfree(psci_states);
336 	return ret;
337 }
338 
339 #ifdef CONFIG_ACPI
340 #include <acpi/processor.h>
341 
342 static int __maybe_unused psci_acpi_cpu_init_idle(unsigned int cpu)
343 {
344 	int i, count;
345 	u32 *psci_states;
346 	struct acpi_lpi_state *lpi;
347 	struct acpi_processor *pr = per_cpu(processors, cpu);
348 
349 	if (unlikely(!pr || !pr->flags.has_lpi))
350 		return -EINVAL;
351 
352 	count = pr->power.count - 1;
353 	if (count <= 0)
354 		return -ENODEV;
355 
356 	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
357 	if (!psci_states)
358 		return -ENOMEM;
359 
360 	for (i = 0; i < count; i++) {
361 		u32 state;
362 
363 		lpi = &pr->power.lpi_states[i + 1];
364 		/*
365 		 * Only bits[31:0] represent a PSCI power_state while
366 		 * bits[63:32] must be 0x0 as per ARM ACPI FFH Specification
367 		 */
368 		state = lpi->address;
369 		if (!psci_power_state_is_valid(state)) {
370 			pr_warn("Invalid PSCI power state %#x\n", state);
371 			kfree(psci_states);
372 			return -EINVAL;
373 		}
374 		psci_states[i] = state;
375 	}
376 	/* Idle states parsed correctly, initialize per-cpu pointer */
377 	per_cpu(psci_power_state, cpu) = psci_states;
378 	return 0;
379 }
380 #else
381 static int __maybe_unused psci_acpi_cpu_init_idle(unsigned int cpu)
382 {
383 	return -EINVAL;
384 }
385 #endif
386 
387 int psci_cpu_init_idle(unsigned int cpu)
388 {
389 	struct device_node *cpu_node;
390 	int ret;
391 
392 	/*
393 	 * If the PSCI cpu_suspend function hook has not been initialized
394 	 * idle states must not be enabled, so bail out
395 	 */
396 	if (!psci_ops.cpu_suspend)
397 		return -EOPNOTSUPP;
398 
399 	if (!acpi_disabled)
400 		return psci_acpi_cpu_init_idle(cpu);
401 
402 	cpu_node = of_get_cpu_node(cpu, NULL);
403 	if (!cpu_node)
404 		return -ENODEV;
405 
406 	ret = psci_dt_cpu_init_idle(cpu_node, cpu);
407 
408 	of_node_put(cpu_node);
409 
410 	return ret;
411 }
412 
413 static int psci_suspend_finisher(unsigned long index)
414 {
415 	u32 *state = __this_cpu_read(psci_power_state);
416 
417 	return psci_ops.cpu_suspend(state[index - 1],
418 				    __pa_symbol(cpu_resume));
419 }
420 
421 int psci_cpu_suspend_enter(unsigned long index)
422 {
423 	int ret;
424 	u32 *state = __this_cpu_read(psci_power_state);
425 	/*
426 	 * idle state index 0 corresponds to wfi, should never be called
427 	 * from the cpu_suspend operations
428 	 */
429 	if (WARN_ON_ONCE(!index))
430 		return -EINVAL;
431 
432 	if (!psci_power_state_loses_context(state[index - 1]))
433 		ret = psci_ops.cpu_suspend(state[index - 1], 0);
434 	else
435 		ret = cpu_suspend(index, psci_suspend_finisher);
436 
437 	return ret;
438 }
439 
440 /* ARM specific CPU idle operations */
441 #ifdef CONFIG_ARM
442 static const struct cpuidle_ops psci_cpuidle_ops __initconst = {
443 	.suspend = psci_cpu_suspend_enter,
444 	.init = psci_dt_cpu_init_idle,
445 };
446 
447 CPUIDLE_METHOD_OF_DECLARE(psci, "psci", &psci_cpuidle_ops);
448 #endif
449 #endif
450 
451 static int psci_system_suspend(unsigned long unused)
452 {
453 	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
454 			      __pa_symbol(cpu_resume), 0, 0);
455 }
456 
457 static int psci_system_suspend_enter(suspend_state_t state)
458 {
459 	return cpu_suspend(0, psci_system_suspend);
460 }
461 
462 static const struct platform_suspend_ops psci_suspend_ops = {
463 	.valid          = suspend_valid_only_mem,
464 	.enter          = psci_system_suspend_enter,
465 };
466 
467 static void __init psci_init_system_reset2(void)
468 {
469 	int ret;
470 
471 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
472 
473 	if (ret != PSCI_RET_NOT_SUPPORTED)
474 		psci_system_reset2_supported = true;
475 }
476 
477 static void __init psci_init_system_suspend(void)
478 {
479 	int ret;
480 
481 	if (!IS_ENABLED(CONFIG_SUSPEND))
482 		return;
483 
484 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
485 
486 	if (ret != PSCI_RET_NOT_SUPPORTED)
487 		suspend_set_ops(&psci_suspend_ops);
488 }
489 
490 static void __init psci_init_cpu_suspend(void)
491 {
492 	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
493 
494 	if (feature != PSCI_RET_NOT_SUPPORTED)
495 		psci_cpu_suspend_feature = feature;
496 }
497 
498 /*
499  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
500  * return DENIED (which would be fatal).
501  */
502 static void __init psci_init_migrate(void)
503 {
504 	unsigned long cpuid;
505 	int type, cpu = -1;
506 
507 	type = psci_ops.migrate_info_type();
508 
509 	if (type == PSCI_0_2_TOS_MP) {
510 		pr_info("Trusted OS migration not required\n");
511 		return;
512 	}
513 
514 	if (type == PSCI_RET_NOT_SUPPORTED) {
515 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
516 		return;
517 	}
518 
519 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
520 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
521 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
522 		return;
523 	}
524 
525 	cpuid = psci_migrate_info_up_cpu();
526 	if (cpuid & ~MPIDR_HWID_BITMASK) {
527 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
528 			cpuid);
529 		return;
530 	}
531 
532 	cpu = get_logical_index(cpuid);
533 	resident_cpu = cpu >= 0 ? cpu : -1;
534 
535 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
536 }
537 
538 static void __init psci_init_smccc(void)
539 {
540 	u32 ver = ARM_SMCCC_VERSION_1_0;
541 	int feature;
542 
543 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
544 
545 	if (feature != PSCI_RET_NOT_SUPPORTED) {
546 		u32 ret;
547 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
548 		if (ret == ARM_SMCCC_VERSION_1_1) {
549 			psci_ops.smccc_version = SMCCC_VERSION_1_1;
550 			ver = ret;
551 		}
552 	}
553 
554 	/*
555 	 * Conveniently, the SMCCC and PSCI versions are encoded the
556 	 * same way. No, this isn't accidental.
557 	 */
558 	pr_info("SMC Calling Convention v%d.%d\n",
559 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
560 
561 }
562 
563 static void __init psci_0_2_set_functions(void)
564 {
565 	pr_info("Using standard PSCI v0.2 function IDs\n");
566 	psci_ops.get_version = psci_get_version;
567 
568 	psci_function_id[PSCI_FN_CPU_SUSPEND] =
569 					PSCI_FN_NATIVE(0_2, CPU_SUSPEND);
570 	psci_ops.cpu_suspend = psci_cpu_suspend;
571 
572 	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
573 	psci_ops.cpu_off = psci_cpu_off;
574 
575 	psci_function_id[PSCI_FN_CPU_ON] = PSCI_FN_NATIVE(0_2, CPU_ON);
576 	psci_ops.cpu_on = psci_cpu_on;
577 
578 	psci_function_id[PSCI_FN_MIGRATE] = PSCI_FN_NATIVE(0_2, MIGRATE);
579 	psci_ops.migrate = psci_migrate;
580 
581 	psci_ops.affinity_info = psci_affinity_info;
582 
583 	psci_ops.migrate_info_type = psci_migrate_info_type;
584 
585 	arm_pm_restart = psci_sys_reset;
586 
587 	pm_power_off = psci_sys_poweroff;
588 }
589 
590 /*
591  * Probe function for PSCI firmware versions >= 0.2
592  */
593 static int __init psci_probe(void)
594 {
595 	u32 ver = psci_get_version();
596 
597 	pr_info("PSCIv%d.%d detected in firmware.\n",
598 			PSCI_VERSION_MAJOR(ver),
599 			PSCI_VERSION_MINOR(ver));
600 
601 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
602 		pr_err("Conflicting PSCI version detected.\n");
603 		return -EINVAL;
604 	}
605 
606 	psci_0_2_set_functions();
607 
608 	psci_init_migrate();
609 
610 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
611 		psci_init_smccc();
612 		psci_init_cpu_suspend();
613 		psci_init_system_suspend();
614 		psci_init_system_reset2();
615 	}
616 
617 	return 0;
618 }
619 
620 typedef int (*psci_initcall_t)(const struct device_node *);
621 
622 /*
623  * PSCI init function for PSCI versions >=0.2
624  *
625  * Probe based on PSCI PSCI_VERSION function
626  */
627 static int __init psci_0_2_init(struct device_node *np)
628 {
629 	int err;
630 
631 	err = get_set_conduit_method(np);
632 	if (err)
633 		return err;
634 
635 	/*
636 	 * Starting with v0.2, the PSCI specification introduced a call
637 	 * (PSCI_VERSION) that allows probing the firmware version, so
638 	 * that PSCI function IDs and version specific initialization
639 	 * can be carried out according to the specific version reported
640 	 * by firmware
641 	 */
642 	return psci_probe();
643 }
644 
645 /*
646  * PSCI < v0.2 get PSCI Function IDs via DT.
647  */
648 static int __init psci_0_1_init(struct device_node *np)
649 {
650 	u32 id;
651 	int err;
652 
653 	err = get_set_conduit_method(np);
654 	if (err)
655 		return err;
656 
657 	pr_info("Using PSCI v0.1 Function IDs from DT\n");
658 
659 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
660 		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
661 		psci_ops.cpu_suspend = psci_cpu_suspend;
662 	}
663 
664 	if (!of_property_read_u32(np, "cpu_off", &id)) {
665 		psci_function_id[PSCI_FN_CPU_OFF] = id;
666 		psci_ops.cpu_off = psci_cpu_off;
667 	}
668 
669 	if (!of_property_read_u32(np, "cpu_on", &id)) {
670 		psci_function_id[PSCI_FN_CPU_ON] = id;
671 		psci_ops.cpu_on = psci_cpu_on;
672 	}
673 
674 	if (!of_property_read_u32(np, "migrate", &id)) {
675 		psci_function_id[PSCI_FN_MIGRATE] = id;
676 		psci_ops.migrate = psci_migrate;
677 	}
678 
679 	return 0;
680 }
681 
682 static int __init psci_1_0_init(struct device_node *np)
683 {
684 	int err;
685 
686 	err = psci_0_2_init(np);
687 	if (err)
688 		return err;
689 
690 	if (psci_has_osi_support())
691 		pr_info("OSI mode supported.\n");
692 
693 	return 0;
694 }
695 
696 static const struct of_device_id psci_of_match[] __initconst = {
697 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
698 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
699 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
700 	{},
701 };
702 
703 int __init psci_dt_init(void)
704 {
705 	struct device_node *np;
706 	const struct of_device_id *matched_np;
707 	psci_initcall_t init_fn;
708 	int ret;
709 
710 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
711 
712 	if (!np || !of_device_is_available(np))
713 		return -ENODEV;
714 
715 	init_fn = (psci_initcall_t)matched_np->data;
716 	ret = init_fn(np);
717 
718 	of_node_put(np);
719 	return ret;
720 }
721 
722 #ifdef CONFIG_ACPI
723 /*
724  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
725  * explicitly clarified in SBBR
726  */
727 int __init psci_acpi_init(void)
728 {
729 	if (!acpi_psci_present()) {
730 		pr_info("is not implemented in ACPI.\n");
731 		return -EOPNOTSUPP;
732 	}
733 
734 	pr_info("probing for conduit method from ACPI.\n");
735 
736 	if (acpi_psci_use_hvc())
737 		set_conduit(PSCI_CONDUIT_HVC);
738 	else
739 		set_conduit(PSCI_CONDUIT_SMC);
740 
741 	return psci_probe();
742 }
743 #endif
744