xref: /linux/drivers/firmware/psci/psci.c (revision 65b09bfa8aa7ebe087093b591525385efb2d58b0) 
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 static bool psci_system_off2_hibernate_supported;
82 
83 static inline bool psci_has_ext_power_state(void)
84 {
85 	return psci_cpu_suspend_feature &
86 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
87 }
88 
89 bool psci_has_osi_support(void)
90 {
91 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
92 }
93 
94 static inline bool psci_power_state_loses_context(u32 state)
95 {
96 	const u32 mask = psci_has_ext_power_state() ?
97 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
98 					PSCI_0_2_POWER_STATE_TYPE_MASK;
99 
100 	return state & mask;
101 }
102 
103 bool psci_power_state_is_valid(u32 state)
104 {
105 	const u32 valid_mask = psci_has_ext_power_state() ?
106 			       PSCI_1_0_EXT_POWER_STATE_MASK :
107 			       PSCI_0_2_POWER_STATE_MASK;
108 
109 	return !(state & ~valid_mask);
110 }
111 
112 static __always_inline unsigned long
113 __invoke_psci_fn_hvc(unsigned long function_id,
114 		     unsigned long arg0, unsigned long arg1,
115 		     unsigned long arg2)
116 {
117 	struct arm_smccc_res res;
118 
119 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
120 	return res.a0;
121 }
122 
123 static __always_inline unsigned long
124 __invoke_psci_fn_smc(unsigned long function_id,
125 		     unsigned long arg0, unsigned long arg1,
126 		     unsigned long arg2)
127 {
128 	struct arm_smccc_res res;
129 
130 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
131 	return res.a0;
132 }
133 
134 static __always_inline int psci_to_linux_errno(int errno)
135 {
136 	switch (errno) {
137 	case PSCI_RET_SUCCESS:
138 		return 0;
139 	case PSCI_RET_NOT_SUPPORTED:
140 		return -EOPNOTSUPP;
141 	case PSCI_RET_INVALID_PARAMS:
142 	case PSCI_RET_INVALID_ADDRESS:
143 		return -EINVAL;
144 	case PSCI_RET_DENIED:
145 		return -EPERM;
146 	}
147 
148 	return -EINVAL;
149 }
150 
151 static u32 psci_0_1_get_version(void)
152 {
153 	return PSCI_VERSION(0, 1);
154 }
155 
156 static u32 psci_0_2_get_version(void)
157 {
158 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
159 }
160 
161 int psci_set_osi_mode(bool enable)
162 {
163 	unsigned long suspend_mode;
164 	int err;
165 
166 	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
167 			PSCI_1_0_SUSPEND_MODE_PC;
168 
169 	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
170 	if (err < 0)
171 		pr_info(FW_BUG "failed to set %s mode: %d\n",
172 				enable ? "OSI" : "PC", err);
173 	return psci_to_linux_errno(err);
174 }
175 
176 static __always_inline int
177 __psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
178 {
179 	int err;
180 
181 	err = invoke_psci_fn(fn, state, entry_point, 0);
182 	return psci_to_linux_errno(err);
183 }
184 
185 static __always_inline int
186 psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
187 {
188 	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
189 				  state, entry_point);
190 }
191 
192 static __always_inline int
193 psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
194 {
195 	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
196 				  state, entry_point);
197 }
198 
199 static int __psci_cpu_off(u32 fn, u32 state)
200 {
201 	int err;
202 
203 	err = invoke_psci_fn(fn, state, 0, 0);
204 	return psci_to_linux_errno(err);
205 }
206 
207 static int psci_0_1_cpu_off(u32 state)
208 {
209 	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
210 }
211 
212 static int psci_0_2_cpu_off(u32 state)
213 {
214 	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
215 }
216 
217 static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
218 {
219 	int err;
220 
221 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
222 	return psci_to_linux_errno(err);
223 }
224 
225 static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
226 {
227 	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
228 }
229 
230 static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
231 {
232 	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
233 }
234 
235 static int __psci_migrate(u32 fn, unsigned long cpuid)
236 {
237 	int err;
238 
239 	err = invoke_psci_fn(fn, cpuid, 0, 0);
240 	return psci_to_linux_errno(err);
241 }
242 
243 static int psci_0_1_migrate(unsigned long cpuid)
244 {
245 	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
246 }
247 
248 static int psci_0_2_migrate(unsigned long cpuid)
249 {
250 	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
251 }
252 
253 static int psci_affinity_info(unsigned long target_affinity,
254 		unsigned long lowest_affinity_level)
255 {
256 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
257 			      target_affinity, lowest_affinity_level, 0);
258 }
259 
260 static int psci_migrate_info_type(void)
261 {
262 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
263 }
264 
265 static unsigned long psci_migrate_info_up_cpu(void)
266 {
267 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
268 			      0, 0, 0);
269 }
270 
271 static void set_conduit(enum arm_smccc_conduit conduit)
272 {
273 	switch (conduit) {
274 	case SMCCC_CONDUIT_HVC:
275 		invoke_psci_fn = __invoke_psci_fn_hvc;
276 		break;
277 	case SMCCC_CONDUIT_SMC:
278 		invoke_psci_fn = __invoke_psci_fn_smc;
279 		break;
280 	default:
281 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
282 	}
283 
284 	psci_conduit = conduit;
285 }
286 
287 static int get_set_conduit_method(const struct device_node *np)
288 {
289 	const char *method;
290 
291 	pr_info("probing for conduit method from DT.\n");
292 
293 	if (of_property_read_string(np, "method", &method)) {
294 		pr_warn("missing \"method\" property\n");
295 		return -ENXIO;
296 	}
297 
298 	if (!strcmp("hvc", method)) {
299 		set_conduit(SMCCC_CONDUIT_HVC);
300 	} else if (!strcmp("smc", method)) {
301 		set_conduit(SMCCC_CONDUIT_SMC);
302 	} else {
303 		pr_warn("invalid \"method\" property: %s\n", method);
304 		return -EINVAL;
305 	}
306 	return 0;
307 }
308 
309 static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
310 			  void *data)
311 {
312 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
313 	    psci_system_reset2_supported) {
314 		/*
315 		 * reset_type[31] = 0 (architectural)
316 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
317 		 * cookie = 0 (ignored by the implementation)
318 		 */
319 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
320 	} else {
321 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
322 	}
323 
324 	return NOTIFY_DONE;
325 }
326 
327 static struct notifier_block psci_sys_reset_nb = {
328 	.notifier_call = psci_sys_reset,
329 	.priority = 129,
330 };
331 
332 static void psci_sys_poweroff(void)
333 {
334 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
335 }
336 
337 #ifdef CONFIG_HIBERNATION
338 static int psci_sys_hibernate(struct sys_off_data *data)
339 {
340 	/*
341 	 * If no hibernate type is specified SYSTEM_OFF2 defaults to selecting
342 	 * HIBERNATE_OFF.
343 	 *
344 	 * There are hypervisors in the wild that do not align with the spec and
345 	 * reject calls that explicitly provide a hibernate type. For
346 	 * compatibility with these nonstandard implementations, pass 0 as the
347 	 * type.
348 	 */
349 	if (system_entering_hibernation())
350 		invoke_psci_fn(PSCI_FN_NATIVE(1_3, SYSTEM_OFF2), 0, 0, 0);
351 	return NOTIFY_DONE;
352 }
353 
354 static int __init psci_hibernate_init(void)
355 {
356 	if (psci_system_off2_hibernate_supported) {
357 		/* Higher priority than EFI shutdown, but only for hibernate */
358 		register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
359 					 SYS_OFF_PRIO_FIRMWARE + 2,
360 					 psci_sys_hibernate, NULL);
361 	}
362 	return 0;
363 }
364 subsys_initcall(psci_hibernate_init);
365 #endif
366 
367 static int psci_features(u32 psci_func_id)
368 {
369 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
370 			      psci_func_id, 0, 0);
371 }
372 
373 #ifdef CONFIG_DEBUG_FS
374 
375 #define PSCI_ID(ver, _name) \
376 	{ .fn = PSCI_##ver##_FN_##_name, .name = #_name, }
377 #define PSCI_ID_NATIVE(ver, _name) \
378 	{ .fn = PSCI_FN_NATIVE(ver, _name), .name = #_name, }
379 
380 /* A table of all optional functions */
381 static const struct {
382 	u32 fn;
383 	const char *name;
384 } psci_fn_ids[] = {
385 	PSCI_ID_NATIVE(0_2, MIGRATE),
386 	PSCI_ID(0_2, MIGRATE_INFO_TYPE),
387 	PSCI_ID_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
388 	PSCI_ID(1_0, CPU_FREEZE),
389 	PSCI_ID_NATIVE(1_0, CPU_DEFAULT_SUSPEND),
390 	PSCI_ID_NATIVE(1_0, NODE_HW_STATE),
391 	PSCI_ID_NATIVE(1_0, SYSTEM_SUSPEND),
392 	PSCI_ID(1_0, SET_SUSPEND_MODE),
393 	PSCI_ID_NATIVE(1_0, STAT_RESIDENCY),
394 	PSCI_ID_NATIVE(1_0, STAT_COUNT),
395 	PSCI_ID_NATIVE(1_1, SYSTEM_RESET2),
396 	PSCI_ID(1_1, MEM_PROTECT),
397 	PSCI_ID_NATIVE(1_1, MEM_PROTECT_CHECK_RANGE),
398 	PSCI_ID_NATIVE(1_3, SYSTEM_OFF2),
399 };
400 
401 static int psci_debugfs_read(struct seq_file *s, void *data)
402 {
403 	int feature, type, i;
404 	u32 ver;
405 
406 	ver = psci_ops.get_version();
407 	seq_printf(s, "PSCIv%d.%d\n",
408 		   PSCI_VERSION_MAJOR(ver),
409 		   PSCI_VERSION_MINOR(ver));
410 
411 	/* PSCI_FEATURES is available only starting from 1.0 */
412 	if (PSCI_VERSION_MAJOR(ver) < 1)
413 		return 0;
414 
415 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
416 	if (feature != PSCI_RET_NOT_SUPPORTED) {
417 		ver = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
418 		seq_printf(s, "SMC Calling Convention v%d.%d\n",
419 			   PSCI_VERSION_MAJOR(ver),
420 			   PSCI_VERSION_MINOR(ver));
421 	} else {
422 		seq_puts(s, "SMC Calling Convention v1.0 is assumed\n");
423 	}
424 
425 	feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
426 	if (feature < 0) {
427 		seq_printf(s, "PSCI_FEATURES(CPU_SUSPEND) error (%d)\n", feature);
428 	} else {
429 		seq_printf(s, "OSI is %ssupported\n",
430 			   (feature & BIT(0)) ? "" : "not ");
431 		seq_printf(s, "%s StateID format is used\n",
432 			   (feature & BIT(1)) ? "Extended" : "Original");
433 	}
434 
435 	type = psci_ops.migrate_info_type();
436 	if (type == PSCI_0_2_TOS_UP_MIGRATE ||
437 	    type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
438 		unsigned long cpuid;
439 
440 		seq_printf(s, "Trusted OS %smigrate capable\n",
441 			   type == PSCI_0_2_TOS_UP_NO_MIGRATE ? "not " : "");
442 		cpuid = psci_migrate_info_up_cpu();
443 		seq_printf(s, "Trusted OS resident on physical CPU 0x%lx (#%d)\n",
444 			   cpuid, resident_cpu);
445 	} else if (type == PSCI_0_2_TOS_MP) {
446 		seq_puts(s, "Trusted OS migration not required\n");
447 	} else {
448 		if (type != PSCI_RET_NOT_SUPPORTED)
449 			seq_printf(s, "MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
450 	}
451 
452 	for (i = 0; i < ARRAY_SIZE(psci_fn_ids); i++) {
453 		feature = psci_features(psci_fn_ids[i].fn);
454 		if (feature == PSCI_RET_NOT_SUPPORTED)
455 			continue;
456 		if (feature < 0)
457 			seq_printf(s, "PSCI_FEATURES(%s) error (%d)\n",
458 				   psci_fn_ids[i].name, feature);
459 		else
460 			seq_printf(s, "%s is supported\n", psci_fn_ids[i].name);
461 	}
462 
463 	return 0;
464 }
465 
466 static int psci_debugfs_open(struct inode *inode, struct file *f)
467 {
468 	return single_open(f, psci_debugfs_read, NULL);
469 }
470 
471 static const struct file_operations psci_debugfs_ops = {
472 	.owner = THIS_MODULE,
473 	.open = psci_debugfs_open,
474 	.release = single_release,
475 	.read = seq_read,
476 	.llseek = seq_lseek
477 };
478 
479 static int __init psci_debugfs_init(void)
480 {
481 	if (!invoke_psci_fn || !psci_ops.get_version)
482 		return 0;
483 
484 	return PTR_ERR_OR_ZERO(debugfs_create_file("psci", 0444, NULL, NULL,
485 						   &psci_debugfs_ops));
486 }
487 late_initcall(psci_debugfs_init)
488 #endif
489 
490 #ifdef CONFIG_CPU_IDLE
491 static noinstr int psci_suspend_finisher(unsigned long state)
492 {
493 	u32 power_state = state;
494 	phys_addr_t pa_cpu_resume;
495 
496 	pa_cpu_resume = __pa_symbol_nodebug((unsigned long)cpu_resume);
497 
498 	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
499 }
500 
501 int psci_cpu_suspend_enter(u32 state)
502 {
503 	int ret;
504 
505 	if (!psci_power_state_loses_context(state)) {
506 		struct arm_cpuidle_irq_context context;
507 
508 		ct_cpuidle_enter();
509 		arm_cpuidle_save_irq_context(&context);
510 		ret = psci_ops.cpu_suspend(state, 0);
511 		arm_cpuidle_restore_irq_context(&context);
512 		ct_cpuidle_exit();
513 	} else {
514 		/*
515 		 * ARM64 cpu_suspend() wants to do ct_cpuidle_*() itself.
516 		 */
517 		if (!IS_ENABLED(CONFIG_ARM64))
518 			ct_cpuidle_enter();
519 
520 		ret = cpu_suspend(state, psci_suspend_finisher);
521 
522 		if (!IS_ENABLED(CONFIG_ARM64))
523 			ct_cpuidle_exit();
524 	}
525 
526 	return ret;
527 }
528 #endif
529 
530 static int psci_system_suspend(unsigned long unused)
531 {
532 	int err;
533 	phys_addr_t pa_cpu_resume = __pa_symbol(cpu_resume);
534 
535 	err = invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
536 			      pa_cpu_resume, 0, 0);
537 	return psci_to_linux_errno(err);
538 }
539 
540 static int psci_system_suspend_enter(suspend_state_t state)
541 {
542 	pm_set_resume_via_firmware();
543 
544 	return cpu_suspend(0, psci_system_suspend);
545 }
546 
547 static int psci_system_suspend_begin(suspend_state_t state)
548 {
549 	pm_set_suspend_via_firmware();
550 
551 	return 0;
552 }
553 
554 static const struct platform_suspend_ops psci_suspend_ops = {
555 	.valid          = suspend_valid_only_mem,
556 	.enter          = psci_system_suspend_enter,
557 	.begin          = psci_system_suspend_begin,
558 };
559 
560 static void __init psci_init_system_reset2(void)
561 {
562 	int ret;
563 
564 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
565 
566 	if (ret != PSCI_RET_NOT_SUPPORTED)
567 		psci_system_reset2_supported = true;
568 }
569 
570 static void __init psci_init_system_off2(void)
571 {
572 	int ret;
573 
574 	ret = psci_features(PSCI_FN_NATIVE(1_3, SYSTEM_OFF2));
575 	if (ret < 0)
576 		return;
577 
578 	if (ret & PSCI_1_3_OFF_TYPE_HIBERNATE_OFF)
579 		psci_system_off2_hibernate_supported = true;
580 }
581 
582 static void __init psci_init_system_suspend(void)
583 {
584 	int ret;
585 
586 	if (!IS_ENABLED(CONFIG_SUSPEND))
587 		return;
588 
589 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
590 
591 	if (ret != PSCI_RET_NOT_SUPPORTED)
592 		suspend_set_ops(&psci_suspend_ops);
593 }
594 
595 static void __init psci_init_cpu_suspend(void)
596 {
597 	int feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
598 
599 	if (feature != PSCI_RET_NOT_SUPPORTED)
600 		psci_cpu_suspend_feature = feature;
601 }
602 
603 /*
604  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
605  * return DENIED (which would be fatal).
606  */
607 static void __init psci_init_migrate(void)
608 {
609 	unsigned long cpuid;
610 	int type, cpu = -1;
611 
612 	type = psci_ops.migrate_info_type();
613 
614 	if (type == PSCI_0_2_TOS_MP) {
615 		pr_info("Trusted OS migration not required\n");
616 		return;
617 	}
618 
619 	if (type == PSCI_RET_NOT_SUPPORTED) {
620 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
621 		return;
622 	}
623 
624 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
625 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
626 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
627 		return;
628 	}
629 
630 	cpuid = psci_migrate_info_up_cpu();
631 	if (cpuid & ~MPIDR_HWID_BITMASK) {
632 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
633 			cpuid);
634 		return;
635 	}
636 
637 	cpu = get_logical_index(cpuid);
638 	resident_cpu = cpu >= 0 ? cpu : -1;
639 
640 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
641 }
642 
643 static void __init psci_init_smccc(void)
644 {
645 	u32 ver = ARM_SMCCC_VERSION_1_0;
646 	int feature;
647 
648 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
649 
650 	if (feature != PSCI_RET_NOT_SUPPORTED) {
651 		u32 ret;
652 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
653 		if (ret >= ARM_SMCCC_VERSION_1_1) {
654 			arm_smccc_version_init(ret, psci_conduit);
655 			ver = ret;
656 		}
657 	}
658 
659 	/*
660 	 * Conveniently, the SMCCC and PSCI versions are encoded the
661 	 * same way. No, this isn't accidental.
662 	 */
663 	pr_info("SMC Calling Convention v%d.%d\n",
664 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
665 
666 }
667 
668 static void __init psci_0_2_set_functions(void)
669 {
670 	pr_info("Using standard PSCI v0.2 function IDs\n");
671 
672 	psci_ops = (struct psci_operations){
673 		.get_version = psci_0_2_get_version,
674 		.cpu_suspend = psci_0_2_cpu_suspend,
675 		.cpu_off = psci_0_2_cpu_off,
676 		.cpu_on = psci_0_2_cpu_on,
677 		.migrate = psci_0_2_migrate,
678 		.affinity_info = psci_affinity_info,
679 		.migrate_info_type = psci_migrate_info_type,
680 	};
681 
682 	register_restart_handler(&psci_sys_reset_nb);
683 
684 	pm_power_off = psci_sys_poweroff;
685 }
686 
687 /*
688  * Probe function for PSCI firmware versions >= 0.2
689  */
690 static int __init psci_probe(void)
691 {
692 	u32 ver = psci_0_2_get_version();
693 
694 	pr_info("PSCIv%d.%d detected in firmware.\n",
695 			PSCI_VERSION_MAJOR(ver),
696 			PSCI_VERSION_MINOR(ver));
697 
698 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
699 		pr_err("Conflicting PSCI version detected.\n");
700 		return -EINVAL;
701 	}
702 
703 	psci_0_2_set_functions();
704 
705 	psci_init_migrate();
706 
707 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
708 		psci_init_smccc();
709 		psci_init_cpu_suspend();
710 		psci_init_system_suspend();
711 		psci_init_system_reset2();
712 		psci_init_system_off2();
713 		kvm_init_hyp_services();
714 	}
715 
716 	return 0;
717 }
718 
719 typedef int (*psci_initcall_t)(const struct device_node *);
720 
721 /*
722  * PSCI init function for PSCI versions >=0.2
723  *
724  * Probe based on PSCI PSCI_VERSION function
725  */
726 static int __init psci_0_2_init(const struct device_node *np)
727 {
728 	int err;
729 
730 	err = get_set_conduit_method(np);
731 	if (err)
732 		return err;
733 
734 	/*
735 	 * Starting with v0.2, the PSCI specification introduced a call
736 	 * (PSCI_VERSION) that allows probing the firmware version, so
737 	 * that PSCI function IDs and version specific initialization
738 	 * can be carried out according to the specific version reported
739 	 * by firmware
740 	 */
741 	return psci_probe();
742 }
743 
744 /*
745  * PSCI < v0.2 get PSCI Function IDs via DT.
746  */
747 static int __init psci_0_1_init(const struct device_node *np)
748 {
749 	u32 id;
750 	int err;
751 
752 	err = get_set_conduit_method(np);
753 	if (err)
754 		return err;
755 
756 	pr_info("Using PSCI v0.1 Function IDs from DT\n");
757 
758 	psci_ops.get_version = psci_0_1_get_version;
759 
760 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
761 		psci_0_1_function_ids.cpu_suspend = id;
762 		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
763 	}
764 
765 	if (!of_property_read_u32(np, "cpu_off", &id)) {
766 		psci_0_1_function_ids.cpu_off = id;
767 		psci_ops.cpu_off = psci_0_1_cpu_off;
768 	}
769 
770 	if (!of_property_read_u32(np, "cpu_on", &id)) {
771 		psci_0_1_function_ids.cpu_on = id;
772 		psci_ops.cpu_on = psci_0_1_cpu_on;
773 	}
774 
775 	if (!of_property_read_u32(np, "migrate", &id)) {
776 		psci_0_1_function_ids.migrate = id;
777 		psci_ops.migrate = psci_0_1_migrate;
778 	}
779 
780 	return 0;
781 }
782 
783 static int __init psci_1_0_init(const struct device_node *np)
784 {
785 	int err;
786 
787 	err = psci_0_2_init(np);
788 	if (err)
789 		return err;
790 
791 	if (psci_has_osi_support()) {
792 		pr_info("OSI mode supported.\n");
793 
794 		/* Default to PC mode. */
795 		psci_set_osi_mode(false);
796 	}
797 
798 	return 0;
799 }
800 
801 static const struct of_device_id psci_of_match[] __initconst = {
802 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
803 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
804 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
805 	{},
806 };
807 
808 int __init psci_dt_init(void)
809 {
810 	struct device_node *np;
811 	const struct of_device_id *matched_np;
812 	psci_initcall_t init_fn;
813 	int ret;
814 
815 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
816 
817 	if (!np || !of_device_is_available(np)) {
818 		of_node_put(np);
819 		return -ENODEV;
820 	}
821 
822 	init_fn = (psci_initcall_t)matched_np->data;
823 	ret = init_fn(np);
824 
825 	of_node_put(np);
826 	return ret;
827 }
828 
829 #ifdef CONFIG_ACPI
830 /*
831  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
832  * explicitly clarified in SBBR
833  */
834 int __init psci_acpi_init(void)
835 {
836 	if (!acpi_psci_present()) {
837 		pr_info("is not implemented in ACPI.\n");
838 		return -EOPNOTSUPP;
839 	}
840 
841 	pr_info("probing for conduit method from ACPI.\n");
842 
843 	if (acpi_psci_use_hvc())
844 		set_conduit(SMCCC_CONDUIT_HVC);
845 	else
846 		set_conduit(SMCCC_CONDUIT_SMC);
847 
848 	return psci_probe();
849 }
850 #endif
851