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
psci_boot_secondary(unsigned int cpu,struct task_struct * idle)45 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
46 {
47 if (psci_ops.cpu_on)
48 #ifdef CONFIG_XIP_KERNEL
49 return psci_ops.cpu_on(cpu_logical_map(cpu),
50 ((phys_addr_t)(&secondary_startup)
51 - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR)
52 + CONFIG_XIP_PHYS_ADDR));
53 #else
54 return psci_ops.cpu_on(cpu_logical_map(cpu),
55 virt_to_idmap(&secondary_startup));
56 #endif
57 return -ENODEV;
58 }
59
60 #ifdef CONFIG_HOTPLUG_CPU
psci_cpu_disable(unsigned int cpu)61 static int psci_cpu_disable(unsigned int cpu)
62 {
63 /* Fail early if we don't have CPU_OFF support */
64 if (!psci_ops.cpu_off)
65 return -EOPNOTSUPP;
66
67 /* Trusted OS will deny CPU_OFF */
68 if (psci_tos_resident_on(cpu))
69 return -EPERM;
70
71 return 0;
72 }
73
psci_cpu_die(unsigned int cpu)74 static void psci_cpu_die(unsigned int cpu)
75 {
76 u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
77 PSCI_0_2_POWER_STATE_TYPE_SHIFT;
78
79 if (psci_ops.cpu_off)
80 psci_ops.cpu_off(state);
81
82 /* We should never return */
83 panic("psci: cpu %d failed to shutdown\n", cpu);
84 }
85
psci_cpu_kill(unsigned int cpu)86 static int psci_cpu_kill(unsigned int cpu)
87 {
88 int err, i;
89
90 if (!psci_ops.affinity_info)
91 return 1;
92 /*
93 * cpu_kill could race with cpu_die and we can
94 * potentially end up declaring this cpu undead
95 * while it is dying. So, try again a few times.
96 */
97
98 for (i = 0; i < 10; i++) {
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.\n", cpu);
102 return 1;
103 }
104
105 msleep(10);
106 pr_info("Retrying again to check for CPU kill\n");
107 }
108
109 pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
110 cpu, err);
111 /* Make platform_cpu_kill() fail. */
112 return 0;
113 }
114
115 #endif
116
psci_smp_available(void)117 bool __init psci_smp_available(void)
118 {
119 /* is cpu_on available at least? */
120 return (psci_ops.cpu_on != NULL);
121 }
122
123 const struct smp_operations psci_smp_ops __initconst = {
124 .smp_boot_secondary = psci_boot_secondary,
125 #ifdef CONFIG_HOTPLUG_CPU
126 .cpu_disable = psci_cpu_disable,
127 .cpu_die = psci_cpu_die,
128 .cpu_kill = psci_cpu_kill,
129 #endif
130 };
131