xref: /linux/arch/arm64/kernel/psci.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright (C) 2013 ARM Limited
5  *
6  * Author: Will Deacon <will.deacon@arm.com>
7  */
8 
9 #define pr_fmt(fmt) "psci: " fmt
10 
11 #include <linux/init.h>
12 #include <linux/of.h>
13 #include <linux/smp.h>
14 #include <linux/delay.h>
15 #include <linux/psci.h>
16 #include <linux/mm.h>
17 
18 #include <uapi/linux/psci.h>
19 
20 #include <asm/cpu_ops.h>
21 #include <asm/errno.h>
22 #include <asm/smp_plat.h>
23 
cpu_psci_cpu_init(unsigned int cpu)24 static int __init cpu_psci_cpu_init(unsigned int cpu)
25 {
26 	return 0;
27 }
28 
cpu_psci_cpu_prepare(unsigned int cpu)29 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
30 {
31 	if (!psci_ops.cpu_on) {
32 		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
33 		return -ENODEV;
34 	}
35 
36 	return 0;
37 }
38 
cpu_psci_cpu_boot(unsigned int cpu)39 static int cpu_psci_cpu_boot(unsigned int cpu)
40 {
41 	phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
42 	int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
43 	if (err && err != -EPERM)
44 		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
45 
46 	return err;
47 }
48 
49 #ifdef CONFIG_HOTPLUG_CPU
cpu_psci_cpu_can_disable(unsigned int cpu)50 static bool cpu_psci_cpu_can_disable(unsigned int cpu)
51 {
52 	return !psci_tos_resident_on(cpu);
53 }
54 
cpu_psci_cpu_disable(unsigned int cpu)55 static int cpu_psci_cpu_disable(unsigned int cpu)
56 {
57 	/* Fail early if we don't have CPU_OFF support */
58 	if (!psci_ops.cpu_off)
59 		return -EOPNOTSUPP;
60 
61 	/* Trusted OS will deny CPU_OFF */
62 	if (psci_tos_resident_on(cpu))
63 		return -EPERM;
64 
65 	return 0;
66 }
67 
cpu_psci_cpu_die(unsigned int cpu)68 static void cpu_psci_cpu_die(unsigned int cpu)
69 {
70 	/*
71 	 * There are no known implementations of PSCI actually using the
72 	 * power state field, pass a sensible default for now.
73 	 */
74 	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
75 		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
76 
77 	psci_ops.cpu_off(state);
78 }
79 
cpu_psci_cpu_kill(unsigned int cpu)80 static int cpu_psci_cpu_kill(unsigned int cpu)
81 {
82 	int err;
83 	unsigned long start, end;
84 
85 	if (!psci_ops.affinity_info)
86 		return 0;
87 	/*
88 	 * cpu_kill could race with cpu_die and we can
89 	 * potentially end up declaring this cpu undead
90 	 * while it is dying. So, try again a few times.
91 	 */
92 
93 	start = jiffies;
94 	end = start + msecs_to_jiffies(100);
95 	do {
96 		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
97 		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
98 			pr_info("CPU%d killed (polled %d ms)\n", cpu,
99 				jiffies_to_msecs(jiffies - start));
100 			return 0;
101 		}
102 
103 		usleep_range(100, 1000);
104 	} while (time_before(jiffies, end));
105 
106 	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
107 			cpu, err);
108 	return -ETIMEDOUT;
109 }
110 #endif
111 
112 const struct cpu_operations cpu_psci_ops = {
113 	.name		= "psci",
114 	.cpu_init	= cpu_psci_cpu_init,
115 	.cpu_prepare	= cpu_psci_cpu_prepare,
116 	.cpu_boot	= cpu_psci_cpu_boot,
117 #ifdef CONFIG_HOTPLUG_CPU
118 	.cpu_can_disable = cpu_psci_cpu_can_disable,
119 	.cpu_disable	= cpu_psci_cpu_disable,
120 	.cpu_die	= cpu_psci_cpu_die,
121 	.cpu_kill	= cpu_psci_cpu_kill,
122 #endif
123 };
124 
125