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(function_nocfi(secondary_entry));
42 int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
43 if (err)
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