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 int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry));
42 if (err)
43 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
44
45 return err;
46 }
47
48 #ifdef CONFIG_HOTPLUG_CPU
cpu_psci_cpu_can_disable(unsigned int cpu)49 static bool cpu_psci_cpu_can_disable(unsigned int cpu)
50 {
51 return !psci_tos_resident_on(cpu);
52 }
53
cpu_psci_cpu_disable(unsigned int cpu)54 static int cpu_psci_cpu_disable(unsigned int cpu)
55 {
56 /* Fail early if we don't have CPU_OFF support */
57 if (!psci_ops.cpu_off)
58 return -EOPNOTSUPP;
59
60 /* Trusted OS will deny CPU_OFF */
61 if (psci_tos_resident_on(cpu))
62 return -EPERM;
63
64 return 0;
65 }
66
cpu_psci_cpu_die(unsigned int cpu)67 static void cpu_psci_cpu_die(unsigned int cpu)
68 {
69 /*
70 * There are no known implementations of PSCI actually using the
71 * power state field, pass a sensible default for now.
72 */
73 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
74 PSCI_0_2_POWER_STATE_TYPE_SHIFT;
75
76 psci_ops.cpu_off(state);
77 }
78
cpu_psci_cpu_kill(unsigned int cpu)79 static int cpu_psci_cpu_kill(unsigned int cpu)
80 {
81 int err;
82 unsigned long start, end;
83
84 if (!psci_ops.affinity_info)
85 return 0;
86 /*
87 * cpu_kill could race with cpu_die and we can
88 * potentially end up declaring this cpu undead
89 * while it is dying. So, try again a few times.
90 */
91
92 start = jiffies;
93 end = start + msecs_to_jiffies(100);
94 do {
95 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
96 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
97 pr_info("CPU%d killed (polled %d ms)\n", cpu,
98 jiffies_to_msecs(jiffies - start));
99 return 0;
100 }
101
102 usleep_range(100, 1000);
103 } while (time_before(jiffies, end));
104
105 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
106 cpu, err);
107 return -ETIMEDOUT;
108 }
109 #endif
110
111 const struct cpu_operations cpu_psci_ops = {
112 .name = "psci",
113 .cpu_init = cpu_psci_cpu_init,
114 .cpu_prepare = cpu_psci_cpu_prepare,
115 .cpu_boot = cpu_psci_cpu_boot,
116 #ifdef CONFIG_HOTPLUG_CPU
117 .cpu_can_disable = cpu_psci_cpu_can_disable,
118 .cpu_disable = cpu_psci_cpu_disable,
119 .cpu_die = cpu_psci_cpu_die,
120 .cpu_kill = cpu_psci_cpu_kill,
121 #endif
122 };
123
124
