xref: /openbmc/linux/drivers/firmware/psci/psci.c (revision a2cab953) 
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/debugfs.h>
13 #include <linux/errno.h>
14 #include <linux/linkage.h>
15 #include <linux/of.h>
16 #include <linux/pm.h>
17 #include <linux/printk.h>
18 #include <linux/psci.h>
19 #include <linux/reboot.h>
20 #include <linux/slab.h>
21 #include <linux/suspend.h>
22 
23 #include <uapi/linux/psci.h>
24 
25 #include <asm/cpuidle.h>
26 #include <asm/cputype.h>
27 #include <asm/hypervisor.h>
28 #include <asm/system_misc.h>
29 #include <asm/smp_plat.h>
30 #include <asm/suspend.h>
31 
32 /*
33  * While a 64-bit OS can make calls with SMC32 calling conventions, for some
34  * calls it is necessary to use SMC64 to pass or return 64-bit values.
35  * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
36  * (native-width) function ID.
37  */
38 #ifdef CONFIG_64BIT
39 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
40 #else
41 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
42 #endif
43 
44 /*
45  * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
46  * calls to its resident CPU, so we must avoid issuing those. We never migrate
47  * a Trusted OS even if it claims to be capable of migration -- doing so will
48  * require cooperation with a Trusted OS driver.
49  */
50 static int resident_cpu = -1;
51 struct psci_operations psci_ops;
52 static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;
53 
54 bool psci_tos_resident_on(int cpu)
55 {
56 	return cpu == resident_cpu;
57 }
58 
59 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
60 				unsigned long, unsigned long);
61 static psci_fn *invoke_psci_fn;
62 
63 static struct psci_0_1_function_ids psci_0_1_function_ids;
64 
65 struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
66 {
67 	return psci_0_1_function_ids;
68 }
69 
70 #define PSCI_0_2_POWER_STATE_MASK		\
71 				(PSCI_0_2_POWER_STATE_ID_MASK | \
72 				PSCI_0_2_POWER_STATE_TYPE_MASK | \
73 				PSCI_0_2_POWER_STATE_AFFL_MASK)
74 
75 #define PSCI_1_0_EXT_POWER_STATE_MASK		\
76 				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
77 				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)
78 
79 static u32 psci_cpu_suspend_feature;
80 static bool psci_system_reset2_supported;
81 
82 static inline bool psci_has_ext_power_state(void)
83 {
84 	return psci_cpu_suspend_feature &
85 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
86 }
87 
88 bool psci_has_osi_support(void)
89 {
90 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
91 }
92 
93 static inline bool psci_power_state_loses_context(u32 state)
94 {
95 	const u32 mask = psci_has_ext_power_state() ?
96 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
97 					PSCI_0_2_POWER_STATE_TYPE_MASK;
98 
99 	return state & mask;
100 }
101 
102 bool psci_power_state_is_valid(u32 state)
103 {
104 	const u32 valid_mask = psci_has_ext_power_state() ?
105 			       PSCI_1_0_EXT_POWER_STATE_MASK :
106 			       PSCI_0_2_POWER_STATE_MASK;
107 
108 	return !(state & ~valid_mask);
109 }
110 
111 static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
112 			unsigned long arg0, unsigned long arg1,
113 			unsigned long arg2)
114 {
115 	struct arm_smccc_res res;
116 
117 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
118 	return res.a0;
119 }
120 
121 static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
122 			unsigned long arg0, unsigned long arg1,
123 			unsigned long arg2)
124 {
125 	struct arm_smccc_res res;
126 
127 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
128 	return res.a0;
129 }
130 
131 static int psci_to_linux_errno(int errno)
132 {
133 	switch (errno) {
134 	case PSCI_RET_SUCCESS:
135 		return 0;
136 	case PSCI_RET_NOT_SUPPORTED:
137 		return -EOPNOTSUPP;
138 	case PSCI_RET_INVALID_PARAMS:
139 	case PSCI_RET_INVALID_ADDRESS:
140 		return -EINVAL;
141 	case PSCI_RET_DENIED:
142 		return -EPERM;
143 	}
144 
145 	return -EINVAL;
146 }
147 
148 static u32 psci_0_1_get_version(void)
149 {
150 	return PSCI_VERSION(0, 1);
151 }
152 
153 static u32 psci_0_2_get_version(void)
154 {
155 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
156 }
157 
158 int psci_set_osi_mode(bool enable)
159 {
160 	unsigned long suspend_mode;
161 	int err;
162 
163 	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
164 			PSCI_1_0_SUSPEND_MODE_PC;
165 
166 	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
167 	if (err < 0)
168 		pr_warn("failed to set %s mode: %d\n", enable ? "OSI" : "PC", err);
169 	return psci_to_linux_errno(err);
170 }
171 
172 static int __psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
173 {
174 	int err;
175 
176 	err = invoke_psci_fn(fn, state, entry_point, 0);
177 	return psci_to_linux_errno(err);
178 }
179 
180 static int psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
181 {
182 	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
183 				  state, entry_point);
184 }
185 
186 static int psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
187 {
188 	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
189 				  state, entry_point);
190 }
191 
192 static int __psci_cpu_off(u32 fn, u32 state)
193 {
194 	int err;
195 
196 	err = invoke_psci_fn(fn, state, 0, 0);
197 	return psci_to_linux_errno(err);
198 }
199 
200 static int psci_0_1_cpu_off(u32 state)
201 {
202 	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
203 }
204 
205 static int psci_0_2_cpu_off(u32 state)
206 {
207 	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
208 }
209 
210 static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
211 {
212 	int err;
213 
214 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
215 	return psci_to_linux_errno(err);
216 }
217 
218 static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
219 {
220 	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
221 }
222 
223 static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
224 {
225 	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
226 }
227 
228 static int __psci_migrate(u32 fn, unsigned long cpuid)
229 {
230 	int err;
231 
232 	err = invoke_psci_fn(fn, cpuid, 0, 0);
233 	return psci_to_linux_errno(err);
234 }
235 
236 static int psci_0_1_migrate(unsigned long cpuid)
237 {
238 	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
239 }
240 
241 static int psci_0_2_migrate(unsigned long cpuid)
242 {
243 	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
244 }
245 
246 static int psci_affinity_info(unsigned long target_affinity,
247 		unsigned long lowest_affinity_level)
248 {
249 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
250 			      target_affinity, lowest_affinity_level, 0);
251 }
252 
253 static int psci_migrate_info_type(void)
254 {
255 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
256 }
257 
258 static unsigned long psci_migrate_info_up_cpu(void)
259 {
260 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
261 			      0, 0, 0);
262 }
263 
264 static void set_conduit(enum arm_smccc_conduit conduit)
265 {
266 	switch (conduit) {
267 	case SMCCC_CONDUIT_HVC:
268 		invoke_psci_fn = __invoke_psci_fn_hvc;
269 		break;
270 	case SMCCC_CONDUIT_SMC:
271 		invoke_psci_fn = __invoke_psci_fn_smc;
272 		break;
273 	default:
274 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
275 	}
276 
277 	psci_conduit = conduit;
278 }
279 
280 static int get_set_conduit_method(const struct device_node *np)
281 {
282 	const char *method;
283 
284 	pr_info("probing for conduit method from DT.\n");
285 
286 	if (of_property_read_string(np, "method", &method)) {
287 		pr_warn("missing \"method\" property\n");
288 		return -ENXIO;
289 	}
290 
291 	if (!strcmp("hvc", method)) {
292 		set_conduit(SMCCC_CONDUIT_HVC);
293 	} else if (!strcmp("smc", method)) {
294 		set_conduit(SMCCC_CONDUIT_SMC);
295 	} else {
296 		pr_warn("invalid \"method\" property: %s\n", method);
297 		return -EINVAL;
298 	}
299 	return 0;
300 }
301 
302 static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
303 			  void *data)
304 {
305 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
306 	    psci_system_reset2_supported) {
307 		/*
308 		 * reset_type[31] = 0 (architectural)
309 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
310 		 * cookie = 0 (ignored by the implementation)
311 		 */
312 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
313 	} else {
314 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
315 	}
316 
317 	return NOTIFY_DONE;
318 }
319 
320 static struct notifier_block psci_sys_reset_nb = {
321 	.notifier_call = psci_sys_reset,
322 	.priority = 129,
323 };
324 
325 static void psci_sys_poweroff(void)
326 {
327 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
328 }
329 
330 static int psci_features(u32 psci_func_id)
331 {
332 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
333 			      psci_func_id, 0, 0);
334 }
335 
336 #ifdef CONFIG_DEBUG_FS
337 
338 #define PSCI_ID(ver, _name) \
339 	{ .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
340 #define PSCI_ID_NATIVE(ver, _name) \
341 	{ .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
342 
343 /* A table of all optional functions */
344 static const struct {
345 	u32 fn;
346 	const char *name;
347 } psci_fn_ids[] = {
348 	PSCI_ID_NATIVE(0_2, MIGRATE),
349 	PSCI_ID(0_2, MIGRATE_INFO_TYPE),
350 	PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
351 	PSCI_ID(1_0, CPU_FREEZE),
352 	PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
353 	PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
354 	PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
355 	PSCI_ID(1_0, SET_SUSPEND_MODE),
356 	PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
357 	PSCI_ID_NATIVE(1_0, STAT_COUNT),
358 	PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
359 	PSCI_ID(1_1, MEM_PROTECT),
360 	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
361 };
362 
363 static int psci_debugfs_read(struct seq_file *s, void *data)
364 {
365 	int feature, type, i;
366 	u32 ver;
367 
368 	ver = psci_ops.get_version();
369 	seq_printf(s, "PSCIv%d.%d\n",
370 		   PSCI_VERSION_MAJOR(ver),
371 		   PSCI_VERSION_MINOR(ver));
372 
373 	/* PSCI_FEATURES is available only starting from 1.0 */
374 	if (PSCI_VERSION_MAJOR(ver) < 1)
375 		return 0;
376 
377 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
378 	if (feature != PSCI_RET_NOT_SUPPORTED) {
379 		ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
380 		seq_printf(s, "SMC Calling Convention v%d.%d\n",
381 			   PSCI_VERSION_MAJOR(ver),
382 			   PSCI_VERSION_MINOR(ver));
383 	} else {
384 		seq_puts(s, "SMC Calling Convention v1.0 is assumed\n");
385 	}
386 
387 	feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
388 	if (feature < 0) {
389 		seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
390 	} else {
391 		seq_printf(s, "OSI is %ssupported\n",
392 			   (feature & BIT(0)) ? "" : "not ");
393 		seq_printf(s, "%s StateID format is used\n",
394 			   (feature & BIT(1)) ? "Extended" : "Original");
395 	}
396 
397 	type = psci_ops.migrate_info_type();
398 	if (type == PSCI_0_2_TOS_UP_MIGRATE ||
399 	    type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
400 		unsigned long cpuid;
401 
402 		seq_printf(s, "Trusted OS %smigrate capable\n",
403 			   type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
404 		cpuid = psci_migrate_info_up_cpu();
405 		seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n",
406 			   cpuid, resident_cpu);
407 	} else if (type == PSCI_0_2_TOS_MP) {
408 		seq_puts(s, "Trusted OS migration not required\n");
409 	} else {
410 		if (type != PSCI_RET_NOT_SUPPORTED)
411 			seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
412 	}
413 
414 	for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
415 		feature = psci_features(psci_fn_ids[i].fn);
416 		if (feature == PSCI_RET_NOT_SUPPORTED)
417 			continue;
418 		if (feature < 0)
419 			seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n",
420 				   psci_fn_ids[i].name, feature);
421 		else
422 			seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
423 	}
424 
425 	return 0;
426 }
427 
428 static int psci_debugfs_open(struct inode *inode, struct file *f)
429 {
430 	return single_open(f, psci_debugfs_read, NULL);
431 }
432 
433 static const struct file_operations psci_debugfs_ops = {
434 	.owner = THIS_MODULE,
435 	.open = psci_debugfs_open,
436 	.release = single_release,
437 	.read = seq_read,
438 	.llseek = seq_lseek
439 };
440 
441 static int __init psci_debugfs_init(void)
442 {
443 	return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL,
444 						   &psci_debugfs_ops));
445 }
446 late_initcall(psci_debugfs_init)
447 #endif
448 
449 #ifdef CONFIG_CPU_IDLE
450 static int psci_suspend_finisher(unsigned long state)
451 {
452 	u32 power_state = state;
453 	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
454 
455 	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
456 }
457 
458 int psci_cpu_suspend_enter(u32 state)
459 {
460 	int ret;
461 
462 	if (!psci_power_state_loses_context(state)) {
463 		struct arm_cpuidle_irq_context context;
464 
465 		arm_cpuidle_save_irq_context(&context);
466 		ret = psci_ops.cpu_suspend(state, 0);
467 		arm_cpuidle_restore_irq_context(&context);
468 	} else {
469 		ret = cpu_suspend(state, psci_suspend_finisher);
470 	}
471 
472 	return ret;
473 }
474 #endif
475 
476 static int psci_system_suspend(unsigned long unused)
477 {
478 	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
479 
480 	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
481 			      pa_cpu_resume, 0, 0);
482 }
483 
484 static int psci_system_suspend_enter(suspend_state_t state)
485 {
486 	return cpu_suspend(0, psci_system_suspend);
487 }
488 
489 static const struct platform_suspend_ops psci_suspend_ops = {
490 	.valid          = suspend_valid_only_mem,
491 	.enter          = psci_system_suspend_enter,
492 };
493 
494 static void __init psci_init_system_reset2(void)
495 {
496 	int ret;
497 
498 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
499 
500 	if (ret != PSCI_RET_NOT_SUPPORTED)
501 		psci_system_reset2_supported = true;
502 }
503 
504 static void __init psci_init_system_suspend(void)
505 {
506 	int ret;
507 
508 	if (!IS_ENABLED(CONFIG_SUSPEND))
509 		return;
510 
511 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
512 
513 	if (ret != PSCI_RET_NOT_SUPPORTED)
514 		suspend_set_ops(&psci_suspend_ops);
515 }
516 
517 static void __init psci_init_cpu_suspend(void)
518 {
519 	int feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
520 
521 	if (feature != PSCI_RET_NOT_SUPPORTED)
522 		psci_cpu_suspend_feature = feature;
523 }
524 
525 /*
526  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
527  * return DENIED (which would be fatal).
528  */
529 static void __init psci_init_migrate(void)
530 {
531 	unsigned long cpuid;
532 	int type, cpu = -1;
533 
534 	type = psci_ops.migrate_info_type();
535 
536 	if (type == PSCI_0_2_TOS_MP) {
537 		pr_info("Trusted OS migration not required\n");
538 		return;
539 	}
540 
541 	if (type == PSCI_RET_NOT_SUPPORTED) {
542 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
543 		return;
544 	}
545 
546 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
547 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
548 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
549 		return;
550 	}
551 
552 	cpuid = psci_migrate_info_up_cpu();
553 	if (cpuid & ~MPIDR_HWID_BITMASK) {
554 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
555 			cpuid);
556 		return;
557 	}
558 
559 	cpu = get_logical_index(cpuid);
560 	resident_cpu = cpu >= 0 ? cpu : -1;
561 
562 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
563 }
564 
565 static void __init psci_init_smccc(void)
566 {
567 	u32 ver = ARM_SMCCC_VERSION_1_0;
568 	int feature;
569 
570 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
571 
572 	if (feature != PSCI_RET_NOT_SUPPORTED) {
573 		u32 ret;
574 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
575 		if (ret >= ARM_SMCCC_VERSION_1_1) {
576 			arm_smccc_version_init(ret, psci_conduit);
577 			ver = ret;
578 		}
579 	}
580 
581 	/*
582 	 * Conveniently, the SMCCC and PSCI versions are encoded the
583 	 * same way. No, this isn't accidental.
584 	 */
585 	pr_info("SMC Calling Convention v%d.%d\n",
586 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
587 
588 }
589 
590 static void __init psci_0_2_set_functions(void)
591 {
592 	pr_info("Using standard PSCI v0.2 function IDs\n");
593 
594 	psci_ops = (struct psci_operations){
595 		.get_version = psci_0_2_get_version,
596 		.cpu_suspend = psci_0_2_cpu_suspend,
597 		.cpu_off = psci_0_2_cpu_off,
598 		.cpu_on = psci_0_2_cpu_on,
599 		.migrate = psci_0_2_migrate,
600 		.affinity_info = psci_affinity_info,
601 		.migrate_info_type = psci_migrate_info_type,
602 	};
603 
604 	register_restart_handler(&psci_sys_reset_nb);
605 
606 	pm_power_off = psci_sys_poweroff;
607 }
608 
609 /*
610  * Probe function for PSCI firmware versions >= 0.2
611  */
612 static int __init psci_probe(void)
613 {
614 	u32 ver = psci_0_2_get_version();
615 
616 	pr_info("PSCIv%d.%d detected in firmware.\n",
617 			PSCI_VERSION_MAJOR(ver),
618 			PSCI_VERSION_MINOR(ver));
619 
620 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
621 		pr_err("Conflicting PSCI version detected.\n");
622 		return -EINVAL;
623 	}
624 
625 	psci_0_2_set_functions();
626 
627 	psci_init_migrate();
628 
629 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
630 		psci_init_smccc();
631 		psci_init_cpu_suspend();
632 		psci_init_system_suspend();
633 		psci_init_system_reset2();
634 		kvm_init_hyp_services();
635 	}
636 
637 	return 0;
638 }
639 
640 typedef int (*psci_initcall_t)(const struct device_node *);
641 
642 /*
643  * PSCI init function for PSCI versions >=0.2
644  *
645  * Probe based on PSCI PSCI_VERSION function
646  */
647 static int __init psci_0_2_init(const struct device_node *np)
648 {
649 	int err;
650 
651 	err = get_set_conduit_method(np);
652 	if (err)
653 		return err;
654 
655 	/*
656 	 * Starting with v0.2, the PSCI specification introduced a call
657 	 * (PSCI_VERSION) that allows probing the firmware version, so
658 	 * that PSCI function IDs and version specific initialization
659 	 * can be carried out according to the specific version reported
660 	 * by firmware
661 	 */
662 	return psci_probe();
663 }
664 
665 /*
666  * PSCI < v0.2 get PSCI Function IDs via DT.
667  */
668 static int __init psci_0_1_init(const struct device_node *np)
669 {
670 	u32 id;
671 	int err;
672 
673 	err = get_set_conduit_method(np);
674 	if (err)
675 		return err;
676 
677 	pr_info("Using PSCI v0.1 Function IDs from DT\n");
678 
679 	psci_ops.get_version = psci_0_1_get_version;
680 
681 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
682 		psci_0_1_function_ids.cpu_suspend = id;
683 		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
684 	}
685 
686 	if (!of_property_read_u32(np, "cpu_off", &id)) {
687 		psci_0_1_function_ids.cpu_off = id;
688 		psci_ops.cpu_off = psci_0_1_cpu_off;
689 	}
690 
691 	if (!of_property_read_u32(np, "cpu_on", &id)) {
692 		psci_0_1_function_ids.cpu_on = id;
693 		psci_ops.cpu_on = psci_0_1_cpu_on;
694 	}
695 
696 	if (!of_property_read_u32(np, "migrate", &id)) {
697 		psci_0_1_function_ids.migrate = id;
698 		psci_ops.migrate = psci_0_1_migrate;
699 	}
700 
701 	return 0;
702 }
703 
704 static int __init psci_1_0_init(const struct device_node *np)
705 {
706 	int err;
707 
708 	err = psci_0_2_init(np);
709 	if (err)
710 		return err;
711 
712 	if (psci_has_osi_support()) {
713 		pr_info("OSI mode supported.\n");
714 
715 		/* Default to PC mode. */
716 		psci_set_osi_mode(false);
717 	}
718 
719 	return 0;
720 }
721 
722 static const struct of_device_id psci_of_match[] __initconst = {
723 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
724 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
725 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
726 	{},
727 };
728 
729 int __init psci_dt_init(void)
730 {
731 	struct device_node *np;
732 	const struct of_device_id *matched_np;
733 	psci_initcall_t init_fn;
734 	int ret;
735 
736 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
737 
738 	if (!np || !of_device_is_available(np))
739 		return -ENODEV;
740 
741 	init_fn = (psci_initcall_t)matched_np->data;
742 	ret = init_fn(np);
743 
744 	of_node_put(np);
745 	return ret;
746 }
747 
748 #ifdef CONFIG_ACPI
749 /*
750  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
751  * explicitly clarified in SBBR
752  */
753 int __init psci_acpi_init(void)
754 {
755 	if (!acpi_psci_present()) {
756 		pr_info("is not implemented in ACPI.\n");
757 		return -EOPNOTSUPP;
758 	}
759 
760 	pr_info("probing for conduit method from ACPI.\n");
761 
762 	if (acpi_psci_use_hvc())
763 		set_conduit(SMCCC_CONDUIT_HVC);
764 	else
765 		set_conduit(SMCCC_CONDUIT_SMC);
766 
767 	return psci_probe();
768 }
769 #endif
770