xref: /openbmc/linux/drivers/firmware/psci/psci.c (revision aa0dc6a7) 
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/hypervisor.h>
27 #include <asm/system_misc.h>
28 #include <asm/smp_plat.h>
29 #include <asm/suspend.h>
30 
31 /*
32  * While a 64-bit OS can make calls with SMC32 calling conventions, for some
33  * calls it is necessary to use SMC64 to pass or return 64-bit values.
34  * For such calls PSCI_FN_NATIVE(version, name) will choose the appropriate
35  * (native-width) function ID.
36  */
37 #ifdef CONFIG_64BIT
38 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN64_##name
39 #else
40 #define PSCI_FN_NATIVE(version, name)	PSCI_##version##_FN_##name
41 #endif
42 
43 /*
44  * The CPU any Trusted OS is resident on. The trusted OS may reject CPU_OFF
45  * calls to its resident CPU, so we must avoid issuing those. We never migrate
46  * a Trusted OS even if it claims to be capable of migration -- doing so will
47  * require cooperation with a Trusted OS driver.
48  */
49 static int resident_cpu = -1;
50 struct psci_operations psci_ops;
51 static enum arm_smccc_conduit psci_conduit = SMCCC_CONDUIT_NONE;
52 
53 bool psci_tos_resident_on(int cpu)
54 {
55 	return cpu == resident_cpu;
56 }
57 
58 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
59 				unsigned long, unsigned long);
60 static psci_fn *invoke_psci_fn;
61 
62 static struct psci_0_1_function_ids psci_0_1_function_ids;
63 
64 struct psci_0_1_function_ids get_psci_0_1_function_ids(void)
65 {
66 	return psci_0_1_function_ids;
67 }
68 
69 #define PSCI_0_2_POWER_STATE_MASK		\
70 				(PSCI_0_2_POWER_STATE_ID_MASK | \
71 				PSCI_0_2_POWER_STATE_TYPE_MASK | \
72 				PSCI_0_2_POWER_STATE_AFFL_MASK)
73 
74 #define PSCI_1_0_EXT_POWER_STATE_MASK		\
75 				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
76 				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)
77 
78 static u32 psci_cpu_suspend_feature;
79 static bool psci_system_reset2_supported;
80 
81 static inline bool psci_has_ext_power_state(void)
82 {
83 	return psci_cpu_suspend_feature &
84 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
85 }
86 
87 bool psci_has_osi_support(void)
88 {
89 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
90 }
91 
92 static inline bool psci_power_state_loses_context(u32 state)
93 {
94 	const u32 mask = psci_has_ext_power_state() ?
95 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
96 					PSCI_0_2_POWER_STATE_TYPE_MASK;
97 
98 	return state & mask;
99 }
100 
101 bool psci_power_state_is_valid(u32 state)
102 {
103 	const u32 valid_mask = psci_has_ext_power_state() ?
104 			       PSCI_1_0_EXT_POWER_STATE_MASK :
105 			       PSCI_0_2_POWER_STATE_MASK;
106 
107 	return !(state & ~valid_mask);
108 }
109 
110 static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
111 			unsigned long arg0, unsigned long arg1,
112 			unsigned long arg2)
113 {
114 	struct arm_smccc_res res;
115 
116 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
117 	return res.a0;
118 }
119 
120 static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
121 			unsigned long arg0, unsigned long arg1,
122 			unsigned long arg2)
123 {
124 	struct arm_smccc_res res;
125 
126 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
127 	return res.a0;
128 }
129 
130 static int psci_to_linux_errno(int errno)
131 {
132 	switch (errno) {
133 	case PSCI_RET_SUCCESS:
134 		return 0;
135 	case PSCI_RET_NOT_SUPPORTED:
136 		return -EOPNOTSUPP;
137 	case PSCI_RET_INVALID_PARAMS:
138 	case PSCI_RET_INVALID_ADDRESS:
139 		return -EINVAL;
140 	case PSCI_RET_DENIED:
141 		return -EPERM;
142 	}
143 
144 	return -EINVAL;
145 }
146 
147 static u32 psci_0_1_get_version(void)
148 {
149 	return PSCI_VERSION(0, 1);
150 }
151 
152 static u32 psci_0_2_get_version(void)
153 {
154 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
155 }
156 
157 int psci_set_osi_mode(bool enable)
158 {
159 	unsigned long suspend_mode;
160 	int err;
161 
162 	suspend_mode = enable ? PSCI_1_0_SUSPEND_MODE_OSI :
163 			PSCI_1_0_SUSPEND_MODE_PC;
164 
165 	err = invoke_psci_fn(PSCI_1_0_FN_SET_SUSPEND_MODE, suspend_mode, 0, 0);
166 	return psci_to_linux_errno(err);
167 }
168 
169 static int __psci_cpu_suspend(u32 fn, u32 state, unsigned long entry_point)
170 {
171 	int err;
172 
173 	err = invoke_psci_fn(fn, state, entry_point, 0);
174 	return psci_to_linux_errno(err);
175 }
176 
177 static int psci_0_1_cpu_suspend(u32 state, unsigned long entry_point)
178 {
179 	return __psci_cpu_suspend(psci_0_1_function_ids.cpu_suspend,
180 				  state, entry_point);
181 }
182 
183 static int psci_0_2_cpu_suspend(u32 state, unsigned long entry_point)
184 {
185 	return __psci_cpu_suspend(PSCI_FN_NATIVE(0_2, CPU_SUSPEND),
186 				  state, entry_point);
187 }
188 
189 static int __psci_cpu_off(u32 fn, u32 state)
190 {
191 	int err;
192 
193 	err = invoke_psci_fn(fn, state, 0, 0);
194 	return psci_to_linux_errno(err);
195 }
196 
197 static int psci_0_1_cpu_off(u32 state)
198 {
199 	return __psci_cpu_off(psci_0_1_function_ids.cpu_off, state);
200 }
201 
202 static int psci_0_2_cpu_off(u32 state)
203 {
204 	return __psci_cpu_off(PSCI_0_2_FN_CPU_OFF, state);
205 }
206 
207 static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point)
208 {
209 	int err;
210 
211 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
212 	return psci_to_linux_errno(err);
213 }
214 
215 static int psci_0_1_cpu_on(unsigned long cpuid, unsigned long entry_point)
216 {
217 	return __psci_cpu_on(psci_0_1_function_ids.cpu_on, cpuid, entry_point);
218 }
219 
220 static int psci_0_2_cpu_on(unsigned long cpuid, unsigned long entry_point)
221 {
222 	return __psci_cpu_on(PSCI_FN_NATIVE(0_2, CPU_ON), cpuid, entry_point);
223 }
224 
225 static int __psci_migrate(u32 fn, unsigned long cpuid)
226 {
227 	int err;
228 
229 	err = invoke_psci_fn(fn, cpuid, 0, 0);
230 	return psci_to_linux_errno(err);
231 }
232 
233 static int psci_0_1_migrate(unsigned long cpuid)
234 {
235 	return __psci_migrate(psci_0_1_function_ids.migrate, cpuid);
236 }
237 
238 static int psci_0_2_migrate(unsigned long cpuid)
239 {
240 	return __psci_migrate(PSCI_FN_NATIVE(0_2, MIGRATE), cpuid);
241 }
242 
243 static int psci_affinity_info(unsigned long target_affinity,
244 		unsigned long lowest_affinity_level)
245 {
246 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
247 			      target_affinity, lowest_affinity_level, 0);
248 }
249 
250 static int psci_migrate_info_type(void)
251 {
252 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
253 }
254 
255 static unsigned long psci_migrate_info_up_cpu(void)
256 {
257 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
258 			      0, 0, 0);
259 }
260 
261 static void set_conduit(enum arm_smccc_conduit conduit)
262 {
263 	switch (conduit) {
264 	case SMCCC_CONDUIT_HVC:
265 		invoke_psci_fn = __invoke_psci_fn_hvc;
266 		break;
267 	case SMCCC_CONDUIT_SMC:
268 		invoke_psci_fn = __invoke_psci_fn_smc;
269 		break;
270 	default:
271 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
272 	}
273 
274 	psci_conduit = conduit;
275 }
276 
277 static int get_set_conduit_method(struct device_node *np)
278 {
279 	const char *method;
280 
281 	pr_info("probing for conduit method from DT.\n");
282 
283 	if (of_property_read_string(np, "method", &method)) {
284 		pr_warn("missing \"method\" property\n");
285 		return -ENXIO;
286 	}
287 
288 	if (!strcmp("hvc", method)) {
289 		set_conduit(SMCCC_CONDUIT_HVC);
290 	} else if (!strcmp("smc", method)) {
291 		set_conduit(SMCCC_CONDUIT_SMC);
292 	} else {
293 		pr_warn("invalid \"method\" property: %s\n", method);
294 		return -EINVAL;
295 	}
296 	return 0;
297 }
298 
299 static int psci_sys_reset(struct notifier_block *nb, unsigned long action,
300 			  void *data)
301 {
302 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
303 	    psci_system_reset2_supported) {
304 		/*
305 		 * reset_type[31] = 0 (architectural)
306 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
307 		 * cookie = 0 (ignored by the implementation)
308 		 */
309 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
310 	} else {
311 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
312 	}
313 
314 	return NOTIFY_DONE;
315 }
316 
317 static struct notifier_block psci_sys_reset_nb = {
318 	.notifier_call = psci_sys_reset,
319 	.priority = 129,
320 };
321 
322 static void psci_sys_poweroff(void)
323 {
324 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
325 }
326 
327 static int __init psci_features(u32 psci_func_id)
328 {
329 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
330 			      psci_func_id, 0, 0);
331 }
332 
333 #ifdef CONFIG_CPU_IDLE
334 static int psci_suspend_finisher(unsigned long state)
335 {
336 	u32 power_state = state;
337 	phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(cpu_resume));
338 
339 	return psci_ops.cpu_suspend(power_state, pa_cpu_resume);
340 }
341 
342 int psci_cpu_suspend_enter(u32 state)
343 {
344 	int ret;
345 
346 	if (!psci_power_state_loses_context(state)) {
347 		struct arm_cpuidle_irq_context context;
348 
349 		arm_cpuidle_save_irq_context(&context);
350 		ret = psci_ops.cpu_suspend(state, 0);
351 		arm_cpuidle_restore_irq_context(&context);
352 	} else {
353 		ret = cpu_suspend(state, psci_suspend_finisher);
354 	}
355 
356 	return ret;
357 }
358 #endif
359 
360 static int psci_system_suspend(unsigned long unused)
361 {
362 	phys_addr_t pa_cpu_resume = __pa_symbol(function_nocfi(cpu_resume));
363 
364 	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
365 			      pa_cpu_resume, 0, 0);
366 }
367 
368 static int psci_system_suspend_enter(suspend_state_t state)
369 {
370 	return cpu_suspend(0, psci_system_suspend);
371 }
372 
373 static const struct platform_suspend_ops psci_suspend_ops = {
374 	.valid          = suspend_valid_only_mem,
375 	.enter          = psci_system_suspend_enter,
376 };
377 
378 static void __init psci_init_system_reset2(void)
379 {
380 	int ret;
381 
382 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
383 
384 	if (ret != PSCI_RET_NOT_SUPPORTED)
385 		psci_system_reset2_supported = true;
386 }
387 
388 static void __init psci_init_system_suspend(void)
389 {
390 	int ret;
391 
392 	if (!IS_ENABLED(CONFIG_SUSPEND))
393 		return;
394 
395 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
396 
397 	if (ret != PSCI_RET_NOT_SUPPORTED)
398 		suspend_set_ops(&psci_suspend_ops);
399 }
400 
401 static void __init psci_init_cpu_suspend(void)
402 {
403 	int feature = psci_features(PSCI_FN_NATIVE(0_2, CPU_SUSPEND));
404 
405 	if (feature != PSCI_RET_NOT_SUPPORTED)
406 		psci_cpu_suspend_feature = feature;
407 }
408 
409 /*
410  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
411  * return DENIED (which would be fatal).
412  */
413 static void __init psci_init_migrate(void)
414 {
415 	unsigned long cpuid;
416 	int type, cpu = -1;
417 
418 	type = psci_ops.migrate_info_type();
419 
420 	if (type == PSCI_0_2_TOS_MP) {
421 		pr_info("Trusted OS migration not required\n");
422 		return;
423 	}
424 
425 	if (type == PSCI_RET_NOT_SUPPORTED) {
426 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
427 		return;
428 	}
429 
430 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
431 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
432 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
433 		return;
434 	}
435 
436 	cpuid = psci_migrate_info_up_cpu();
437 	if (cpuid & ~MPIDR_HWID_BITMASK) {
438 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
439 			cpuid);
440 		return;
441 	}
442 
443 	cpu = get_logical_index(cpuid);
444 	resident_cpu = cpu >= 0 ? cpu : -1;
445 
446 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
447 }
448 
449 static void __init psci_init_smccc(void)
450 {
451 	u32 ver = ARM_SMCCC_VERSION_1_0;
452 	int feature;
453 
454 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
455 
456 	if (feature != PSCI_RET_NOT_SUPPORTED) {
457 		u32 ret;
458 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
459 		if (ret >= ARM_SMCCC_VERSION_1_1) {
460 			arm_smccc_version_init(ret, psci_conduit);
461 			ver = ret;
462 		}
463 	}
464 
465 	/*
466 	 * Conveniently, the SMCCC and PSCI versions are encoded the
467 	 * same way. No, this isn't accidental.
468 	 */
469 	pr_info("SMC Calling Convention v%d.%d\n",
470 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
471 
472 }
473 
474 static void __init psci_0_2_set_functions(void)
475 {
476 	pr_info("Using standard PSCI v0.2 function IDs\n");
477 
478 	psci_ops = (struct psci_operations){
479 		.get_version = psci_0_2_get_version,
480 		.cpu_suspend = psci_0_2_cpu_suspend,
481 		.cpu_off = psci_0_2_cpu_off,
482 		.cpu_on = psci_0_2_cpu_on,
483 		.migrate = psci_0_2_migrate,
484 		.affinity_info = psci_affinity_info,
485 		.migrate_info_type = psci_migrate_info_type,
486 	};
487 
488 	register_restart_handler(&psci_sys_reset_nb);
489 
490 	pm_power_off = psci_sys_poweroff;
491 }
492 
493 /*
494  * Probe function for PSCI firmware versions >= 0.2
495  */
496 static int __init psci_probe(void)
497 {
498 	u32 ver = psci_0_2_get_version();
499 
500 	pr_info("PSCIv%d.%d detected in firmware.\n",
501 			PSCI_VERSION_MAJOR(ver),
502 			PSCI_VERSION_MINOR(ver));
503 
504 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
505 		pr_err("Conflicting PSCI version detected.\n");
506 		return -EINVAL;
507 	}
508 
509 	psci_0_2_set_functions();
510 
511 	psci_init_migrate();
512 
513 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
514 		psci_init_smccc();
515 		psci_init_cpu_suspend();
516 		psci_init_system_suspend();
517 		psci_init_system_reset2();
518 		kvm_init_hyp_services();
519 	}
520 
521 	return 0;
522 }
523 
524 typedef int (*psci_initcall_t)(const struct device_node *);
525 
526 /*
527  * PSCI init function for PSCI versions >=0.2
528  *
529  * Probe based on PSCI PSCI_VERSION function
530  */
531 static int __init psci_0_2_init(struct device_node *np)
532 {
533 	int err;
534 
535 	err = get_set_conduit_method(np);
536 	if (err)
537 		return err;
538 
539 	/*
540 	 * Starting with v0.2, the PSCI specification introduced a call
541 	 * (PSCI_VERSION) that allows probing the firmware version, so
542 	 * that PSCI function IDs and version specific initialization
543 	 * can be carried out according to the specific version reported
544 	 * by firmware
545 	 */
546 	return psci_probe();
547 }
548 
549 /*
550  * PSCI < v0.2 get PSCI Function IDs via DT.
551  */
552 static int __init psci_0_1_init(struct device_node *np)
553 {
554 	u32 id;
555 	int err;
556 
557 	err = get_set_conduit_method(np);
558 	if (err)
559 		return err;
560 
561 	pr_info("Using PSCI v0.1 Function IDs from DT\n");
562 
563 	psci_ops.get_version = psci_0_1_get_version;
564 
565 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
566 		psci_0_1_function_ids.cpu_suspend = id;
567 		psci_ops.cpu_suspend = psci_0_1_cpu_suspend;
568 	}
569 
570 	if (!of_property_read_u32(np, "cpu_off", &id)) {
571 		psci_0_1_function_ids.cpu_off = id;
572 		psci_ops.cpu_off = psci_0_1_cpu_off;
573 	}
574 
575 	if (!of_property_read_u32(np, "cpu_on", &id)) {
576 		psci_0_1_function_ids.cpu_on = id;
577 		psci_ops.cpu_on = psci_0_1_cpu_on;
578 	}
579 
580 	if (!of_property_read_u32(np, "migrate", &id)) {
581 		psci_0_1_function_ids.migrate = id;
582 		psci_ops.migrate = psci_0_1_migrate;
583 	}
584 
585 	return 0;
586 }
587 
588 static int __init psci_1_0_init(struct device_node *np)
589 {
590 	int err;
591 
592 	err = psci_0_2_init(np);
593 	if (err)
594 		return err;
595 
596 	if (psci_has_osi_support()) {
597 		pr_info("OSI mode supported.\n");
598 
599 		/* Default to PC mode. */
600 		psci_set_osi_mode(false);
601 	}
602 
603 	return 0;
604 }
605 
606 static const struct of_device_id psci_of_match[] __initconst = {
607 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
608 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
609 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
610 	{},
611 };
612 
613 int __init psci_dt_init(void)
614 {
615 	struct device_node *np;
616 	const struct of_device_id *matched_np;
617 	psci_initcall_t init_fn;
618 	int ret;
619 
620 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
621 
622 	if (!np || !of_device_is_available(np))
623 		return -ENODEV;
624 
625 	init_fn = (psci_initcall_t)matched_np->data;
626 	ret = init_fn(np);
627 
628 	of_node_put(np);
629 	return ret;
630 }
631 
632 #ifdef CONFIG_ACPI
633 /*
634  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
635  * explicitly clarified in SBBR
636  */
637 int __init psci_acpi_init(void)
638 {
639 	if (!acpi_psci_present()) {
640 		pr_info("is not implemented in ACPI.\n");
641 		return -EOPNOTSUPP;
642 	}
643 
644 	pr_info("probing for conduit method from ACPI.\n");
645 
646 	if (acpi_psci_use_hvc())
647 		set_conduit(SMCCC_CONDUIT_HVC);
648 	else
649 		set_conduit(SMCCC_CONDUIT_SMC);
650 
651 	return psci_probe();
652 }
653 #endif
654