xref: /openbmc/linux/drivers/firmware/psci/psci.c (revision e7253313)
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 = SMCCC_CONDUIT_NONE,
57 	.smccc_version = SMCCC_VERSION_1_0,
58 };
59 
60 enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
61 {
62 	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
63 		return SMCCC_CONDUIT_NONE;
64 
65 	return psci_ops.conduit;
66 }
67 
68 typedef unsigned long (psci_fn)(unsigned long, unsigned long,
69 				unsigned long, unsigned long);
70 static psci_fn *invoke_psci_fn;
71 
72 enum psci_function {
73 	PSCI_FN_CPU_SUSPEND,
74 	PSCI_FN_CPU_ON,
75 	PSCI_FN_CPU_OFF,
76 	PSCI_FN_MIGRATE,
77 	PSCI_FN_MAX,
78 };
79 
80 static u32 psci_function_id[PSCI_FN_MAX];
81 
82 #define PSCI_0_2_POWER_STATE_MASK		\
83 				(PSCI_0_2_POWER_STATE_ID_MASK | \
84 				PSCI_0_2_POWER_STATE_TYPE_MASK | \
85 				PSCI_0_2_POWER_STATE_AFFL_MASK)
86 
87 #define PSCI_1_0_EXT_POWER_STATE_MASK		\
88 				(PSCI_1_0_EXT_POWER_STATE_ID_MASK | \
89 				PSCI_1_0_EXT_POWER_STATE_TYPE_MASK)
90 
91 static u32 psci_cpu_suspend_feature;
92 static bool psci_system_reset2_supported;
93 
94 static inline bool psci_has_ext_power_state(void)
95 {
96 	return psci_cpu_suspend_feature &
97 				PSCI_1_0_FEATURES_CPU_SUSPEND_PF_MASK;
98 }
99 
100 static inline bool psci_has_osi_support(void)
101 {
102 	return psci_cpu_suspend_feature & PSCI_1_0_OS_INITIATED;
103 }
104 
105 static inline bool psci_power_state_loses_context(u32 state)
106 {
107 	const u32 mask = psci_has_ext_power_state() ?
108 					PSCI_1_0_EXT_POWER_STATE_TYPE_MASK :
109 					PSCI_0_2_POWER_STATE_TYPE_MASK;
110 
111 	return state & mask;
112 }
113 
114 bool psci_power_state_is_valid(u32 state)
115 {
116 	const u32 valid_mask = psci_has_ext_power_state() ?
117 			       PSCI_1_0_EXT_POWER_STATE_MASK :
118 			       PSCI_0_2_POWER_STATE_MASK;
119 
120 	return !(state & ~valid_mask);
121 }
122 
123 static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
124 			unsigned long arg0, unsigned long arg1,
125 			unsigned long arg2)
126 {
127 	struct arm_smccc_res res;
128 
129 	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
130 	return res.a0;
131 }
132 
133 static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
134 			unsigned long arg0, unsigned long arg1,
135 			unsigned long arg2)
136 {
137 	struct arm_smccc_res res;
138 
139 	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
140 	return res.a0;
141 }
142 
143 static int psci_to_linux_errno(int errno)
144 {
145 	switch (errno) {
146 	case PSCI_RET_SUCCESS:
147 		return 0;
148 	case PSCI_RET_NOT_SUPPORTED:
149 		return -EOPNOTSUPP;
150 	case PSCI_RET_INVALID_PARAMS:
151 	case PSCI_RET_INVALID_ADDRESS:
152 		return -EINVAL;
153 	case PSCI_RET_DENIED:
154 		return -EPERM;
155 	};
156 
157 	return -EINVAL;
158 }
159 
160 static u32 psci_get_version(void)
161 {
162 	return invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
163 }
164 
165 static int psci_cpu_suspend(u32 state, unsigned long entry_point)
166 {
167 	int err;
168 	u32 fn;
169 
170 	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
171 	err = invoke_psci_fn(fn, state, entry_point, 0);
172 	return psci_to_linux_errno(err);
173 }
174 
175 static int psci_cpu_off(u32 state)
176 {
177 	int err;
178 	u32 fn;
179 
180 	fn = psci_function_id[PSCI_FN_CPU_OFF];
181 	err = invoke_psci_fn(fn, state, 0, 0);
182 	return psci_to_linux_errno(err);
183 }
184 
185 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
186 {
187 	int err;
188 	u32 fn;
189 
190 	fn = psci_function_id[PSCI_FN_CPU_ON];
191 	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
192 	return psci_to_linux_errno(err);
193 }
194 
195 static int psci_migrate(unsigned long cpuid)
196 {
197 	int err;
198 	u32 fn;
199 
200 	fn = psci_function_id[PSCI_FN_MIGRATE];
201 	err = invoke_psci_fn(fn, cpuid, 0, 0);
202 	return psci_to_linux_errno(err);
203 }
204 
205 static int psci_affinity_info(unsigned long target_affinity,
206 		unsigned long lowest_affinity_level)
207 {
208 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, AFFINITY_INFO),
209 			      target_affinity, lowest_affinity_level, 0);
210 }
211 
212 static int psci_migrate_info_type(void)
213 {
214 	return invoke_psci_fn(PSCI_0_2_FN_MIGRATE_INFO_TYPE, 0, 0, 0);
215 }
216 
217 static unsigned long psci_migrate_info_up_cpu(void)
218 {
219 	return invoke_psci_fn(PSCI_FN_NATIVE(0_2, MIGRATE_INFO_UP_CPU),
220 			      0, 0, 0);
221 }
222 
223 static void set_conduit(enum arm_smccc_conduit conduit)
224 {
225 	switch (conduit) {
226 	case SMCCC_CONDUIT_HVC:
227 		invoke_psci_fn = __invoke_psci_fn_hvc;
228 		break;
229 	case SMCCC_CONDUIT_SMC:
230 		invoke_psci_fn = __invoke_psci_fn_smc;
231 		break;
232 	default:
233 		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
234 	}
235 
236 	psci_ops.conduit = conduit;
237 }
238 
239 static int get_set_conduit_method(struct device_node *np)
240 {
241 	const char *method;
242 
243 	pr_info("probing for conduit method from DT.\n");
244 
245 	if (of_property_read_string(np, "method", &method)) {
246 		pr_warn("missing \"method\" property\n");
247 		return -ENXIO;
248 	}
249 
250 	if (!strcmp("hvc", method)) {
251 		set_conduit(SMCCC_CONDUIT_HVC);
252 	} else if (!strcmp("smc", method)) {
253 		set_conduit(SMCCC_CONDUIT_SMC);
254 	} else {
255 		pr_warn("invalid \"method\" property: %s\n", method);
256 		return -EINVAL;
257 	}
258 	return 0;
259 }
260 
261 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
262 {
263 	if ((reboot_mode == REBOOT_WARM || reboot_mode == REBOOT_SOFT) &&
264 	    psci_system_reset2_supported) {
265 		/*
266 		 * reset_type[31] = 0 (architectural)
267 		 * reset_type[30:0] = 0 (SYSTEM_WARM_RESET)
268 		 * cookie = 0 (ignored by the implementation)
269 		 */
270 		invoke_psci_fn(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2), 0, 0, 0);
271 	} else {
272 		invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
273 	}
274 }
275 
276 static void psci_sys_poweroff(void)
277 {
278 	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
279 }
280 
281 static int __init psci_features(u32 psci_func_id)
282 {
283 	return invoke_psci_fn(PSCI_1_0_FN_PSCI_FEATURES,
284 			      psci_func_id, 0, 0);
285 }
286 
287 #ifdef CONFIG_CPU_IDLE
288 static int psci_suspend_finisher(unsigned long state)
289 {
290 	u32 power_state = state;
291 
292 	return psci_ops.cpu_suspend(power_state, __pa_symbol(cpu_resume));
293 }
294 
295 int psci_cpu_suspend_enter(u32 state)
296 {
297 	int ret;
298 
299 	if (!psci_power_state_loses_context(state))
300 		ret = psci_ops.cpu_suspend(state, 0);
301 	else
302 		ret = cpu_suspend(state, psci_suspend_finisher);
303 
304 	return ret;
305 }
306 #endif
307 
308 static int psci_system_suspend(unsigned long unused)
309 {
310 	return invoke_psci_fn(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND),
311 			      __pa_symbol(cpu_resume), 0, 0);
312 }
313 
314 static int psci_system_suspend_enter(suspend_state_t state)
315 {
316 	return cpu_suspend(0, psci_system_suspend);
317 }
318 
319 static const struct platform_suspend_ops psci_suspend_ops = {
320 	.valid          = suspend_valid_only_mem,
321 	.enter          = psci_system_suspend_enter,
322 };
323 
324 static void __init psci_init_system_reset2(void)
325 {
326 	int ret;
327 
328 	ret = psci_features(PSCI_FN_NATIVE(1_1, SYSTEM_RESET2));
329 
330 	if (ret != PSCI_RET_NOT_SUPPORTED)
331 		psci_system_reset2_supported = true;
332 }
333 
334 static void __init psci_init_system_suspend(void)
335 {
336 	int ret;
337 
338 	if (!IS_ENABLED(CONFIG_SUSPEND))
339 		return;
340 
341 	ret = psci_features(PSCI_FN_NATIVE(1_0, SYSTEM_SUSPEND));
342 
343 	if (ret != PSCI_RET_NOT_SUPPORTED)
344 		suspend_set_ops(&psci_suspend_ops);
345 }
346 
347 static void __init psci_init_cpu_suspend(void)
348 {
349 	int feature = psci_features(psci_function_id[PSCI_FN_CPU_SUSPEND]);
350 
351 	if (feature != PSCI_RET_NOT_SUPPORTED)
352 		psci_cpu_suspend_feature = feature;
353 }
354 
355 /*
356  * Detect the presence of a resident Trusted OS which may cause CPU_OFF to
357  * return DENIED (which would be fatal).
358  */
359 static void __init psci_init_migrate(void)
360 {
361 	unsigned long cpuid;
362 	int type, cpu = -1;
363 
364 	type = psci_ops.migrate_info_type();
365 
366 	if (type == PSCI_0_2_TOS_MP) {
367 		pr_info("Trusted OS migration not required\n");
368 		return;
369 	}
370 
371 	if (type == PSCI_RET_NOT_SUPPORTED) {
372 		pr_info("MIGRATE_INFO_TYPE not supported.\n");
373 		return;
374 	}
375 
376 	if (type != PSCI_0_2_TOS_UP_MIGRATE &&
377 	    type != PSCI_0_2_TOS_UP_NO_MIGRATE) {
378 		pr_err("MIGRATE_INFO_TYPE returned unknown type (%d)\n", type);
379 		return;
380 	}
381 
382 	cpuid = psci_migrate_info_up_cpu();
383 	if (cpuid & ~MPIDR_HWID_BITMASK) {
384 		pr_warn("MIGRATE_INFO_UP_CPU reported invalid physical ID (0x%lx)\n",
385 			cpuid);
386 		return;
387 	}
388 
389 	cpu = get_logical_index(cpuid);
390 	resident_cpu = cpu >= 0 ? cpu : -1;
391 
392 	pr_info("Trusted OS resident on physical CPU 0x%lx\n", cpuid);
393 }
394 
395 static void __init psci_init_smccc(void)
396 {
397 	u32 ver = ARM_SMCCC_VERSION_1_0;
398 	int feature;
399 
400 	feature = psci_features(ARM_SMCCC_VERSION_FUNC_ID);
401 
402 	if (feature != PSCI_RET_NOT_SUPPORTED) {
403 		u32 ret;
404 		ret = invoke_psci_fn(ARM_SMCCC_VERSION_FUNC_ID, 0, 0, 0);
405 		if (ret == ARM_SMCCC_VERSION_1_1) {
406 			psci_ops.smccc_version = SMCCC_VERSION_1_1;
407 			ver = ret;
408 		}
409 	}
410 
411 	/*
412 	 * Conveniently, the SMCCC and PSCI versions are encoded the
413 	 * same way. No, this isn't accidental.
414 	 */
415 	pr_info("SMC Calling Convention v%d.%d\n",
416 		PSCI_VERSION_MAJOR(ver), PSCI_VERSION_MINOR(ver));
417 
418 }
419 
420 static void __init psci_0_2_set_functions(void)
421 {
422 	pr_info("Using standard PSCI v0.2 function IDs\n");
423 	psci_ops.get_version = psci_get_version;
424 
425 	psci_function_id[PSCI_FN_CPU_SUSPEND] =
426 					PSCI_FN_NATIVE(0_2, CPU_SUSPEND);
427 	psci_ops.cpu_suspend = psci_cpu_suspend;
428 
429 	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
430 	psci_ops.cpu_off = psci_cpu_off;
431 
432 	psci_function_id[PSCI_FN_CPU_ON] = PSCI_FN_NATIVE(0_2, CPU_ON);
433 	psci_ops.cpu_on = psci_cpu_on;
434 
435 	psci_function_id[PSCI_FN_MIGRATE] = PSCI_FN_NATIVE(0_2, MIGRATE);
436 	psci_ops.migrate = psci_migrate;
437 
438 	psci_ops.affinity_info = psci_affinity_info;
439 
440 	psci_ops.migrate_info_type = psci_migrate_info_type;
441 
442 	arm_pm_restart = psci_sys_reset;
443 
444 	pm_power_off = psci_sys_poweroff;
445 }
446 
447 /*
448  * Probe function for PSCI firmware versions >= 0.2
449  */
450 static int __init psci_probe(void)
451 {
452 	u32 ver = psci_get_version();
453 
454 	pr_info("PSCIv%d.%d detected in firmware.\n",
455 			PSCI_VERSION_MAJOR(ver),
456 			PSCI_VERSION_MINOR(ver));
457 
458 	if (PSCI_VERSION_MAJOR(ver) == 0 && PSCI_VERSION_MINOR(ver) < 2) {
459 		pr_err("Conflicting PSCI version detected.\n");
460 		return -EINVAL;
461 	}
462 
463 	psci_0_2_set_functions();
464 
465 	psci_init_migrate();
466 
467 	if (PSCI_VERSION_MAJOR(ver) >= 1) {
468 		psci_init_smccc();
469 		psci_init_cpu_suspend();
470 		psci_init_system_suspend();
471 		psci_init_system_reset2();
472 	}
473 
474 	return 0;
475 }
476 
477 typedef int (*psci_initcall_t)(const struct device_node *);
478 
479 /*
480  * PSCI init function for PSCI versions >=0.2
481  *
482  * Probe based on PSCI PSCI_VERSION function
483  */
484 static int __init psci_0_2_init(struct device_node *np)
485 {
486 	int err;
487 
488 	err = get_set_conduit_method(np);
489 	if (err)
490 		return err;
491 
492 	/*
493 	 * Starting with v0.2, the PSCI specification introduced a call
494 	 * (PSCI_VERSION) that allows probing the firmware version, so
495 	 * that PSCI function IDs and version specific initialization
496 	 * can be carried out according to the specific version reported
497 	 * by firmware
498 	 */
499 	return psci_probe();
500 }
501 
502 /*
503  * PSCI < v0.2 get PSCI Function IDs via DT.
504  */
505 static int __init psci_0_1_init(struct device_node *np)
506 {
507 	u32 id;
508 	int err;
509 
510 	err = get_set_conduit_method(np);
511 	if (err)
512 		return err;
513 
514 	pr_info("Using PSCI v0.1 Function IDs from DT\n");
515 
516 	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
517 		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
518 		psci_ops.cpu_suspend = psci_cpu_suspend;
519 	}
520 
521 	if (!of_property_read_u32(np, "cpu_off", &id)) {
522 		psci_function_id[PSCI_FN_CPU_OFF] = id;
523 		psci_ops.cpu_off = psci_cpu_off;
524 	}
525 
526 	if (!of_property_read_u32(np, "cpu_on", &id)) {
527 		psci_function_id[PSCI_FN_CPU_ON] = id;
528 		psci_ops.cpu_on = psci_cpu_on;
529 	}
530 
531 	if (!of_property_read_u32(np, "migrate", &id)) {
532 		psci_function_id[PSCI_FN_MIGRATE] = id;
533 		psci_ops.migrate = psci_migrate;
534 	}
535 
536 	return 0;
537 }
538 
539 static int __init psci_1_0_init(struct device_node *np)
540 {
541 	int err;
542 
543 	err = psci_0_2_init(np);
544 	if (err)
545 		return err;
546 
547 	if (psci_has_osi_support())
548 		pr_info("OSI mode supported.\n");
549 
550 	return 0;
551 }
552 
553 static const struct of_device_id psci_of_match[] __initconst = {
554 	{ .compatible = "arm,psci",	.data = psci_0_1_init},
555 	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
556 	{ .compatible = "arm,psci-1.0",	.data = psci_1_0_init},
557 	{},
558 };
559 
560 int __init psci_dt_init(void)
561 {
562 	struct device_node *np;
563 	const struct of_device_id *matched_np;
564 	psci_initcall_t init_fn;
565 	int ret;
566 
567 	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
568 
569 	if (!np || !of_device_is_available(np))
570 		return -ENODEV;
571 
572 	init_fn = (psci_initcall_t)matched_np->data;
573 	ret = init_fn(np);
574 
575 	of_node_put(np);
576 	return ret;
577 }
578 
579 #ifdef CONFIG_ACPI
580 /*
581  * We use PSCI 0.2+ when ACPI is deployed on ARM64 and it's
582  * explicitly clarified in SBBR
583  */
584 int __init psci_acpi_init(void)
585 {
586 	if (!acpi_psci_present()) {
587 		pr_info("is not implemented in ACPI.\n");
588 		return -EOPNOTSUPP;
589 	}
590 
591 	pr_info("probing for conduit method from ACPI.\n");
592 
593 	if (acpi_psci_use_hvc())
594 		set_conduit(SMCCC_CONDUIT_HVC);
595 	else
596 		set_conduit(SMCCC_CONDUIT_SMC);
597 
598 	return psci_probe();
599 }
600 #endif
601