1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (C) 2012 ARM Limited
5 *
6 * Author: Will Deacon <will.deacon@arm.com>
7 */
8
9 #include <linux/init.h>
10 #include <linux/smp.h>
11 #include <linux/of.h>
12 #include <linux/delay.h>
13 #include <linux/psci.h>
14
15 #include <uapi/linux/psci.h>
16
17 #include <asm/psci.h>
18 #include <asm/smp_plat.h>
19
20 /*
21 * psci_smp assumes that the following is true about PSCI:
22 *
23 * cpu_suspend Suspend the execution on a CPU
24 * @state we don't currently describe affinity levels, so just pass 0.
25 * @entry_point the first instruction to be executed on return
26 * returns 0 success, < 0 on failure
27 *
28 * cpu_off Power down a CPU
29 * @state we don't currently describe affinity levels, so just pass 0.
30 * no return on successful call
31 *
32 * cpu_on Power up a CPU
33 * @cpuid cpuid of target CPU, as from MPIDR
34 * @entry_point the first instruction to be executed on return
35 * returns 0 success, < 0 on failure
36 *
37 * migrate Migrate the context to a different CPU
38 * @cpuid cpuid of target CPU, as from MPIDR
39 * returns 0 success, < 0 on failure
40 *
41 */
42
43 extern void secondary_startup(void);
44
45 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
46 {
47 if (psci_ops.cpu_on)
48 return psci_ops.cpu_on(cpu_logical_map(cpu),
49 virt_to_idmap(&secondary_startup));
50 return -ENODEV;
51 }
52
53 #ifdef CONFIG_HOTPLUG_CPU
54 static int 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
67 static void psci_cpu_die(unsigned int cpu)
68 {
69 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
70 PSCI_0_2_POWER_STATE_TYPE_SHIFT;
71
72 if (psci_ops.cpu_off)
73 psci_ops.cpu_off(state);
74
75 /* We should never return */
76 panic("psci: cpu %d failed to shutdown\n", cpu);
77 }
78
79 static int psci_cpu_kill(unsigned int cpu)
80 {
81 int err, i;
82
83 if (!psci_ops.affinity_info)
84 return 1;
85 /*
86 * cpu_kill could race with cpu_die and we can
87 * potentially end up declaring this cpu undead
88 * while it is dying. So, try again a few times.
89 */
90
91 for (i = 0; i < 10; i++) {
92 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
93 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
94 pr_info("CPU%d killed.\n", cpu);
95 return 1;
96 }
97
98 msleep(10);
99 pr_info("Retrying again to check for CPU kill\n");
100 }
101
102 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
103 cpu, err);
104 /* Make platform_cpu_kill() fail. */
105 return 0;
106 }
107
108 #endif
109
110 bool __init psci_smp_available(void)
111 {
112 /* is cpu_on available at least? */
113 return (psci_ops.cpu_on != NULL);
114 }
115
116 const struct smp_operations psci_smp_ops __initconst = {
117 .smp_boot_secondary = psci_boot_secondary,
118 #ifdef CONFIG_HOTPLUG_CPU
119 .cpu_disable = psci_cpu_disable,
120 .cpu_die = psci_cpu_die,
121 .cpu_kill = psci_cpu_kill,
122 #endif
123 };
124
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