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),
42 __pa_function(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 int ret;
71 /*
72 * There are no known implementations of PSCI actually using the
73 * power state field, pass a sensible default for now.
74 */
75 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
76 PSCI_0_2_POWER_STATE_TYPE_SHIFT;
77
78 ret = psci_ops.cpu_off(state);
79
80 pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
81 }
82
cpu_psci_cpu_kill(unsigned int cpu)83 static int cpu_psci_cpu_kill(unsigned int cpu)
84 {
85 int err;
86 unsigned long start, end;
87
88 if (!psci_ops.affinity_info)
89 return 0;
90 /*
91 * cpu_kill could race with cpu_die and we can
92 * potentially end up declaring this cpu undead
93 * while it is dying. So, try again a few times.
94 */
95
96 start = jiffies;
97 end = start + msecs_to_jiffies(100);
98 do {
99 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
100 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
101 pr_info("CPU%d killed (polled %d ms)\n", cpu,
102 jiffies_to_msecs(jiffies - start));
103 return 0;
104 }
105
106 usleep_range(100, 1000);
107 } while (time_before(jiffies, end));
108
109 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
110 cpu, err);
111 return -ETIMEDOUT;
112 }
113 #endif
114
115 const struct cpu_operations cpu_psci_ops = {
116 .name = "psci",
117 .cpu_init = cpu_psci_cpu_init,
118 .cpu_prepare = cpu_psci_cpu_prepare,
119 .cpu_boot = cpu_psci_cpu_boot,
120 #ifdef CONFIG_HOTPLUG_CPU
121 .cpu_can_disable = cpu_psci_cpu_can_disable,
122 .cpu_disable = cpu_psci_cpu_disable,
123 .cpu_die = cpu_psci_cpu_die,
124 .cpu_kill = cpu_psci_cpu_kill,
125 #endif
126 };
127
128