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) 2013 ARM Limited
12 *
13 * Author: Will Deacon <will.deacon@arm.com>
14 */
15
16#define pr_fmt(fmt) "psci: " fmt
17
18#include <linux/init.h>
19#include <linux/of.h>
20#include <linux/smp.h>
21#include <linux/reboot.h>
22#include <linux/pm.h>
23#include <linux/delay.h>
24#include <linux/slab.h>
25#include <uapi/linux/psci.h>
26
27#include <asm/compiler.h>
28#include <asm/cpu_ops.h>
29#include <asm/errno.h>
30#include <asm/psci.h>
31#include <asm/smp_plat.h>
32#include <asm/suspend.h>
33#include <asm/system_misc.h>
34
35#define PSCI_POWER_STATE_TYPE_STANDBY		0
36#define PSCI_POWER_STATE_TYPE_POWER_DOWN	1
37
38struct psci_power_state {
39	u16	id;
40	u8	type;
41	u8	affinity_level;
42};
43
44struct psci_operations {
45	int (*cpu_suspend)(struct psci_power_state state,
46			   unsigned long entry_point);
47	int (*cpu_off)(struct psci_power_state state);
48	int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
49	int (*migrate)(unsigned long cpuid);
50	int (*affinity_info)(unsigned long target_affinity,
51			unsigned long lowest_affinity_level);
52	int (*migrate_info_type)(void);
53};
54
55static struct psci_operations psci_ops;
56
57static int (*invoke_psci_fn)(u64, u64, u64, u64);
58typedef int (*psci_initcall_t)(const struct device_node *);
59
60enum psci_function {
61	PSCI_FN_CPU_SUSPEND,
62	PSCI_FN_CPU_ON,
63	PSCI_FN_CPU_OFF,
64	PSCI_FN_MIGRATE,
65	PSCI_FN_AFFINITY_INFO,
66	PSCI_FN_MIGRATE_INFO_TYPE,
67	PSCI_FN_MAX,
68};
69
70static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state);
71
72static u32 psci_function_id[PSCI_FN_MAX];
73
74static int psci_to_linux_errno(int errno)
75{
76	switch (errno) {
77	case PSCI_RET_SUCCESS:
78		return 0;
79	case PSCI_RET_NOT_SUPPORTED:
80		return -EOPNOTSUPP;
81	case PSCI_RET_INVALID_PARAMS:
82		return -EINVAL;
83	case PSCI_RET_DENIED:
84		return -EPERM;
85	};
86
87	return -EINVAL;
88}
89
90static u32 psci_power_state_pack(struct psci_power_state state)
91{
92	return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
93			& PSCI_0_2_POWER_STATE_ID_MASK) |
94		((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
95		 & PSCI_0_2_POWER_STATE_TYPE_MASK) |
96		((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
97		 & PSCI_0_2_POWER_STATE_AFFL_MASK);
98}
99
100static void psci_power_state_unpack(u32 power_state,
101				    struct psci_power_state *state)
102{
103	state->id = (power_state & PSCI_0_2_POWER_STATE_ID_MASK) >>
104			PSCI_0_2_POWER_STATE_ID_SHIFT;
105	state->type = (power_state & PSCI_0_2_POWER_STATE_TYPE_MASK) >>
106			PSCI_0_2_POWER_STATE_TYPE_SHIFT;
107	state->affinity_level =
108			(power_state & PSCI_0_2_POWER_STATE_AFFL_MASK) >>
109			PSCI_0_2_POWER_STATE_AFFL_SHIFT;
110}
111
112/*
113 * The following two functions are invoked via the invoke_psci_fn pointer
114 * and will not be inlined, allowing us to piggyback on the AAPCS.
115 */
116static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
117					 u64 arg2)
118{
119	asm volatile(
120			__asmeq("%0", "x0")
121			__asmeq("%1", "x1")
122			__asmeq("%2", "x2")
123			__asmeq("%3", "x3")
124			"hvc	#0\n"
125		: "+r" (function_id)
126		: "r" (arg0), "r" (arg1), "r" (arg2));
127
128	return function_id;
129}
130
131static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
132					 u64 arg2)
133{
134	asm volatile(
135			__asmeq("%0", "x0")
136			__asmeq("%1", "x1")
137			__asmeq("%2", "x2")
138			__asmeq("%3", "x3")
139			"smc	#0\n"
140		: "+r" (function_id)
141		: "r" (arg0), "r" (arg1), "r" (arg2));
142
143	return function_id;
144}
145
146static int psci_get_version(void)
147{
148	int err;
149
150	err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
151	return err;
152}
153
154static int psci_cpu_suspend(struct psci_power_state state,
155			    unsigned long entry_point)
156{
157	int err;
158	u32 fn, power_state;
159
160	fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
161	power_state = psci_power_state_pack(state);
162	err = invoke_psci_fn(fn, power_state, entry_point, 0);
163	return psci_to_linux_errno(err);
164}
165
166static int psci_cpu_off(struct psci_power_state state)
167{
168	int err;
169	u32 fn, power_state;
170
171	fn = psci_function_id[PSCI_FN_CPU_OFF];
172	power_state = psci_power_state_pack(state);
173	err = invoke_psci_fn(fn, power_state, 0, 0);
174	return psci_to_linux_errno(err);
175}
176
177static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
178{
179	int err;
180	u32 fn;
181
182	fn = psci_function_id[PSCI_FN_CPU_ON];
183	err = invoke_psci_fn(fn, cpuid, entry_point, 0);
184	return psci_to_linux_errno(err);
185}
186
187static int psci_migrate(unsigned long cpuid)
188{
189	int err;
190	u32 fn;
191
192	fn = psci_function_id[PSCI_FN_MIGRATE];
193	err = invoke_psci_fn(fn, cpuid, 0, 0);
194	return psci_to_linux_errno(err);
195}
196
197static int psci_affinity_info(unsigned long target_affinity,
198		unsigned long lowest_affinity_level)
199{
200	int err;
201	u32 fn;
202
203	fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
204	err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
205	return err;
206}
207
208static int psci_migrate_info_type(void)
209{
210	int err;
211	u32 fn;
212
213	fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
214	err = invoke_psci_fn(fn, 0, 0, 0);
215	return err;
216}
217
218static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node,
219						 unsigned int cpu)
220{
221	int i, ret, count = 0;
222	struct psci_power_state *psci_states;
223	struct device_node *state_node;
224
225	/*
226	 * If the PSCI cpu_suspend function hook has not been initialized
227	 * idle states must not be enabled, so bail out
228	 */
229	if (!psci_ops.cpu_suspend)
230		return -EOPNOTSUPP;
231
232	/* Count idle states */
233	while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
234					      count))) {
235		count++;
236		of_node_put(state_node);
237	}
238
239	if (!count)
240		return -ENODEV;
241
242	psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
243	if (!psci_states)
244		return -ENOMEM;
245
246	for (i = 0; i < count; i++) {
247		u32 psci_power_state;
248
249		state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
250
251		ret = of_property_read_u32(state_node,
252					   "arm,psci-suspend-param",
253					   &psci_power_state);
254		if (ret) {
255			pr_warn(" * %s missing arm,psci-suspend-param property\n",
256				state_node->full_name);
257			of_node_put(state_node);
258			goto free_mem;
259		}
260
261		of_node_put(state_node);
262		pr_debug("psci-power-state %#x index %d\n", psci_power_state,
263							    i);
264		psci_power_state_unpack(psci_power_state, &psci_states[i]);
265	}
266	/* Idle states parsed correctly, initialize per-cpu pointer */
267	per_cpu(psci_power_state, cpu) = psci_states;
268	return 0;
269
270free_mem:
271	kfree(psci_states);
272	return ret;
273}
274
275static int get_set_conduit_method(struct device_node *np)
276{
277	const char *method;
278
279	pr_info("probing for conduit method from DT.\n");
280
281	if (of_property_read_string(np, "method", &method)) {
282		pr_warn("missing \"method\" property\n");
283		return -ENXIO;
284	}
285
286	if (!strcmp("hvc", method)) {
287		invoke_psci_fn = __invoke_psci_fn_hvc;
288	} else if (!strcmp("smc", method)) {
289		invoke_psci_fn = __invoke_psci_fn_smc;
290	} else {
291		pr_warn("invalid \"method\" property: %s\n", method);
292		return -EINVAL;
293	}
294	return 0;
295}
296
297static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
298{
299	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
300}
301
302static void psci_sys_poweroff(void)
303{
304	invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
305}
306
307/*
308 * PSCI Function IDs for v0.2+ are well defined so use
309 * standard values.
310 */
311static int __init psci_0_2_init(struct device_node *np)
312{
313	int err, ver;
314
315	err = get_set_conduit_method(np);
316
317	if (err)
318		goto out_put_node;
319
320	ver = psci_get_version();
321
322	if (ver == PSCI_RET_NOT_SUPPORTED) {
323		/* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
324		pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
325		err = -EOPNOTSUPP;
326		goto out_put_node;
327	} else {
328		pr_info("PSCIv%d.%d detected in firmware.\n",
329				PSCI_VERSION_MAJOR(ver),
330				PSCI_VERSION_MINOR(ver));
331
332		if (PSCI_VERSION_MAJOR(ver) == 0 &&
333				PSCI_VERSION_MINOR(ver) < 2) {
334			err = -EINVAL;
335			pr_err("Conflicting PSCI version detected.\n");
336			goto out_put_node;
337		}
338	}
339
340	pr_info("Using standard PSCI v0.2 function IDs\n");
341	psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
342	psci_ops.cpu_suspend = psci_cpu_suspend;
343
344	psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
345	psci_ops.cpu_off = psci_cpu_off;
346
347	psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
348	psci_ops.cpu_on = psci_cpu_on;
349
350	psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
351	psci_ops.migrate = psci_migrate;
352
353	psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
354	psci_ops.affinity_info = psci_affinity_info;
355
356	psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
357		PSCI_0_2_FN_MIGRATE_INFO_TYPE;
358	psci_ops.migrate_info_type = psci_migrate_info_type;
359
360	arm_pm_restart = psci_sys_reset;
361
362	pm_power_off = psci_sys_poweroff;
363
364out_put_node:
365	of_node_put(np);
366	return err;
367}
368
369/*
370 * PSCI < v0.2 get PSCI Function IDs via DT.
371 */
372static int __init psci_0_1_init(struct device_node *np)
373{
374	u32 id;
375	int err;
376
377	err = get_set_conduit_method(np);
378
379	if (err)
380		goto out_put_node;
381
382	pr_info("Using PSCI v0.1 Function IDs from DT\n");
383
384	if (!of_property_read_u32(np, "cpu_suspend", &id)) {
385		psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
386		psci_ops.cpu_suspend = psci_cpu_suspend;
387	}
388
389	if (!of_property_read_u32(np, "cpu_off", &id)) {
390		psci_function_id[PSCI_FN_CPU_OFF] = id;
391		psci_ops.cpu_off = psci_cpu_off;
392	}
393
394	if (!of_property_read_u32(np, "cpu_on", &id)) {
395		psci_function_id[PSCI_FN_CPU_ON] = id;
396		psci_ops.cpu_on = psci_cpu_on;
397	}
398
399	if (!of_property_read_u32(np, "migrate", &id)) {
400		psci_function_id[PSCI_FN_MIGRATE] = id;
401		psci_ops.migrate = psci_migrate;
402	}
403
404out_put_node:
405	of_node_put(np);
406	return err;
407}
408
409static const struct of_device_id psci_of_match[] __initconst = {
410	{ .compatible = "arm,psci",	.data = psci_0_1_init},
411	{ .compatible = "arm,psci-0.2",	.data = psci_0_2_init},
412	{},
413};
414
415int __init psci_init(void)
416{
417	struct device_node *np;
418	const struct of_device_id *matched_np;
419	psci_initcall_t init_fn;
420
421	np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
422
423	if (!np)
424		return -ENODEV;
425
426	init_fn = (psci_initcall_t)matched_np->data;
427	return init_fn(np);
428}
429
430#ifdef CONFIG_SMP
431
432static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
433{
434	return 0;
435}
436
437static int __init cpu_psci_cpu_prepare(unsigned int cpu)
438{
439	if (!psci_ops.cpu_on) {
440		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
441		return -ENODEV;
442	}
443
444	return 0;
445}
446
447static int cpu_psci_cpu_boot(unsigned int cpu)
448{
449	int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
450	if (err)
451		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
452
453	return err;
454}
455
456#ifdef CONFIG_HOTPLUG_CPU
457static int cpu_psci_cpu_disable(unsigned int cpu)
458{
459	/* Fail early if we don't have CPU_OFF support */
460	if (!psci_ops.cpu_off)
461		return -EOPNOTSUPP;
462	return 0;
463}
464
465static void cpu_psci_cpu_die(unsigned int cpu)
466{
467	int ret;
468	/*
469	 * There are no known implementations of PSCI actually using the
470	 * power state field, pass a sensible default for now.
471	 */
472	struct psci_power_state state = {
473		.type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
474	};
475
476	ret = psci_ops.cpu_off(state);
477
478	pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
479}
480
481static int cpu_psci_cpu_kill(unsigned int cpu)
482{
483	int err, i;
484
485	if (!psci_ops.affinity_info)
486		return 1;
487	/*
488	 * cpu_kill could race with cpu_die and we can
489	 * potentially end up declaring this cpu undead
490	 * while it is dying. So, try again a few times.
491	 */
492
493	for (i = 0; i < 10; i++) {
494		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
495		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
496			pr_info("CPU%d killed.\n", cpu);
497			return 1;
498		}
499
500		msleep(10);
501		pr_info("Retrying again to check for CPU kill\n");
502	}
503
504	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
505			cpu, err);
506	/* Make op_cpu_kill() fail. */
507	return 0;
508}
509#endif
510#endif
511
512static int psci_suspend_finisher(unsigned long index)
513{
514	struct psci_power_state *state = __get_cpu_var(psci_power_state);
515
516	return psci_ops.cpu_suspend(state[index - 1],
517				    virt_to_phys(cpu_resume));
518}
519
520static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
521{
522	int ret;
523	struct psci_power_state *state = __get_cpu_var(psci_power_state);
524	/*
525	 * idle state index 0 corresponds to wfi, should never be called
526	 * from the cpu_suspend operations
527	 */
528	if (WARN_ON_ONCE(!index))
529		return -EINVAL;
530
531	if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
532		ret = psci_ops.cpu_suspend(state[index - 1], 0);
533	else
534		ret = __cpu_suspend(index, psci_suspend_finisher);
535
536	return ret;
537}
538
539const struct cpu_operations cpu_psci_ops = {
540	.name		= "psci",
541#ifdef CONFIG_CPU_IDLE
542	.cpu_init_idle	= cpu_psci_cpu_init_idle,
543	.cpu_suspend	= cpu_psci_cpu_suspend,
544#endif
545#ifdef CONFIG_SMP
546	.cpu_init	= cpu_psci_cpu_init,
547	.cpu_prepare	= cpu_psci_cpu_prepare,
548	.cpu_boot	= cpu_psci_cpu_boot,
549#ifdef CONFIG_HOTPLUG_CPU
550	.cpu_disable	= cpu_psci_cpu_disable,
551	.cpu_die	= cpu_psci_cpu_die,
552	.cpu_kill	= cpu_psci_cpu_kill,
553#endif
554#endif
555};
556
557