arch/arm64/kernel/psci.c

   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         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa_symbol(secondary_entry));
  42         if (err)
  43                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
  44
  45         return err;
  46 }
  47
  48 #ifdef CONFIG_HOTPLUG_CPU
  49 static int cpu_psci_cpu_disable(unsigned int cpu)
  50 {
  51         /* Fail early if we don't have CPU_OFF support */
  52         if (!psci_ops.cpu_off)
  53                 return -EOPNOTSUPP;
  54
  55         /* Trusted OS will deny CPU_OFF */
  56         if (psci_tos_resident_on(cpu))
  57                 return -EPERM;
  58
  59         return 0;
  60 }
  61
  62 static void cpu_psci_cpu_die(unsigned int cpu)
  63 {
  64         int ret;
  65         /*
  66          * There are no known implementations of PSCI actually using the
  67          * power state field, pass a sensible default for now.
  68          */
  69         u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
  70                     PSCI_0_2_POWER_STATE_TYPE_SHIFT;
  71
  72         ret = psci_ops.cpu_off(state);
  73
  74         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
  75 }
  76
  77 static int cpu_psci_cpu_kill(unsigned int cpu)
  78 {
  79         int err, i;
  80
  81         if (!psci_ops.affinity_info)
  82                 return 0;
  83         /*
  84          * cpu_kill could race with cpu_die and we can
  85          * potentially end up declaring this cpu undead
  86          * while it is dying. So, try again a few times.
  87          */
  88
  89         for (i = 0; i < 10; i++) {
  90                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
  91                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
  92                         pr_info("CPU%d killed.\n", cpu);
  93                         return 0;
  94                 }
  95
  96                 msleep(10);
  97                 pr_info("Retrying again to check for CPU kill\n");
  98         }
  99
 100         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 101                         cpu, err);
 102         return -ETIMEDOUT;
 103 }
 104 #endif
 105
 106 const struct cpu_operations cpu_psci_ops = {
 107         .name           = "psci",
 108 #ifdef CONFIG_CPU_IDLE
 109         .cpu_init_idle  = psci_cpu_init_idle,
 110         .cpu_suspend    = psci_cpu_suspend_enter,
 111 #endif
 112         .cpu_init       = cpu_psci_cpu_init,
 113         .cpu_prepare    = cpu_psci_cpu_prepare,
 114         .cpu_boot       = cpu_psci_cpu_boot,
 115 #ifdef CONFIG_HOTPLUG_CPU
 116         .cpu_disable    = cpu_psci_cpu_disable,
 117         .cpu_die        = cpu_psci_cpu_die,
 118         .cpu_kill       = cpu_psci_cpu_kill,
 119 #endif
 120 };
 121