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 | |
24 | static int __init cpu_psci_cpu_init(unsigned int cpu) |
25 | { |
26 | return 0; |
27 | } |
28 | |
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 | |
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) |
44 | pr_err("failed to boot CPU%d (%d)\n" , cpu, err); |
45 | |
46 | return err; |
47 | } |
48 | |
49 | #ifdef CONFIG_HOTPLUG_CPU |
50 | static bool cpu_psci_cpu_can_disable(unsigned int cpu) |
51 | { |
52 | return !psci_tos_resident_on(cpu); |
53 | } |
54 | |
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 | |
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 | |
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(m: 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(min: 100, max: 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 | |