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