arch/arm64/kernel/psci.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2013 ARM Limited
  12  *
  13  * Author: Will Deacon <will.deacon@arm.com>
  14  */
  15
  16 #define pr_fmt(fmt) "psci: " fmt
  17
  18 #include <linux/init.h>
  19 #include <linux/of.h>
  20 #include <linux/smp.h>
  21 #include <linux/delay.h>
  22 #include <linux/psci.h>
  23 #include <linux/slab.h>
  24
  25 #include <uapi/linux/psci.h>
  26
  27 #include <asm/compiler.h>
  28 #include <asm/cpu_ops.h>
  29 #include <asm/errno.h>
  30 #include <asm/smp_plat.h>
  31 #include <asm/suspend.h>
  32
  33 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
  34
  35 static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
  36 {
  37         int i, ret, count = 0;
  38         u32 *psci_states;
  39         struct device_node *state_node, *cpu_node;
  40
  41         cpu_node = of_get_cpu_node(cpu, NULL);
  42         if (!cpu_node)
  43                 return -ENODEV;
  44
  45         /*
  46          * If the PSCI cpu_suspend function hook has not been initialized
  47          * idle states must not be enabled, so bail out
  48          */
  49         if (!psci_ops.cpu_suspend)
  50                 return -EOPNOTSUPP;
  51
  52         /* Count idle states */
  53         while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
  54                                               count))) {
  55                 count++;
  56                 of_node_put(state_node);
  57         }
  58
  59         if (!count)
  60                 return -ENODEV;
  61
  62         psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
  63         if (!psci_states)
  64                 return -ENOMEM;
  65
  66         for (i = 0; i < count; i++) {
  67                 u32 state;
  68
  69                 state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
  70
  71                 ret = of_property_read_u32(state_node,
  72                                            "arm,psci-suspend-param",
  73                                            &state);
  74                 if (ret) {
  75                         pr_warn(" * %s missing arm,psci-suspend-param property\n",
  76                                 state_node->full_name);
  77                         of_node_put(state_node);
  78                         goto free_mem;
  79                 }
  80
  81                 of_node_put(state_node);
  82                 pr_debug("psci-power-state %#x index %d\n", state, i);
  83                 if (!psci_power_state_is_valid(state)) {
  84                         pr_warn("Invalid PSCI power state %#x\n", state);
  85                         ret = -EINVAL;
  86                         goto free_mem;
  87                 }
  88                 psci_states[i] = state;
  89         }
  90         /* Idle states parsed correctly, initialize per-cpu pointer */
  91         per_cpu(psci_power_state, cpu) = psci_states;
  92         return 0;
  93
  94 free_mem:
  95         kfree(psci_states);
  96         return ret;
  97 }
  98
  99 static int __init cpu_psci_cpu_init(unsigned int cpu)
 100 {
 101         return 0;
 102 }
 103
 104 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 105 {
 106         if (!psci_ops.cpu_on) {
 107                 pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 108                 return -ENODEV;
 109         }
 110
 111         return 0;
 112 }
 113
 114 static int cpu_psci_cpu_boot(unsigned int cpu)
 115 {
 116         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 117         if (err)
 118                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 119
 120         return err;
 121 }
 122
 123 #ifdef CONFIG_HOTPLUG_CPU
 124 static int cpu_psci_cpu_disable(unsigned int cpu)
 125 {
 126         /* Fail early if we don't have CPU_OFF support */
 127         if (!psci_ops.cpu_off)
 128                 return -EOPNOTSUPP;
 129
 130         /* Trusted OS will deny CPU_OFF */
 131         if (psci_tos_resident_on(cpu))
 132                 return -EPERM;
 133
 134         return 0;
 135 }
 136
 137 static void cpu_psci_cpu_die(unsigned int cpu)
 138 {
 139         int ret;
 140         /*
 141          * There are no known implementations of PSCI actually using the
 142          * power state field, pass a sensible default for now.
 143          */
 144         u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
 145                     PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 146
 147         ret = psci_ops.cpu_off(state);
 148
 149         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 150 }
 151
 152 static int cpu_psci_cpu_kill(unsigned int cpu)
 153 {
 154         int err, i;
 155
 156         if (!psci_ops.affinity_info)
 157                 return 0;
 158         /*
 159          * cpu_kill could race with cpu_die and we can
 160          * potentially end up declaring this cpu undead
 161          * while it is dying. So, try again a few times.
 162          */
 163
 164         for (i = 0; i < 10; i++) {
 165                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 166                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 167                         pr_info("CPU%d killed.\n", cpu);
 168                         return 0;
 169                 }
 170
 171                 msleep(10);
 172                 pr_info("Retrying again to check for CPU kill\n");
 173         }
 174
 175         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 176                         cpu, err);
 177         return -ETIMEDOUT;
 178 }
 179 #endif
 180
 181 static int psci_suspend_finisher(unsigned long index)
 182 {
 183         u32 *state = __this_cpu_read(psci_power_state);
 184
 185         return psci_ops.cpu_suspend(state[index - 1],
 186                                     virt_to_phys(cpu_resume));
 187 }
 188
 189 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
 190 {
 191         int ret;
 192         u32 *state = __this_cpu_read(psci_power_state);
 193         /*
 194          * idle state index 0 corresponds to wfi, should never be called
 195          * from the cpu_suspend operations
 196          */
 197         if (WARN_ON_ONCE(!index))
 198                 return -EINVAL;
 199
 200         if (!psci_power_state_loses_context(state[index - 1]))
 201                 ret = psci_ops.cpu_suspend(state[index - 1], 0);
 202         else
 203                 ret = cpu_suspend(index, psci_suspend_finisher);
 204
 205         return ret;
 206 }
 207
 208 const struct cpu_operations cpu_psci_ops = {
 209         .name           = "psci",
 210 #ifdef CONFIG_CPU_IDLE
 211         .cpu_init_idle  = cpu_psci_cpu_init_idle,
 212         .cpu_suspend    = cpu_psci_cpu_suspend,
 213 #endif
 214         .cpu_init       = cpu_psci_cpu_init,
 215         .cpu_prepare    = cpu_psci_cpu_prepare,
 216         .cpu_boot       = cpu_psci_cpu_boot,
 217 #ifdef CONFIG_HOTPLUG_CPU
 218         .cpu_disable    = cpu_psci_cpu_disable,
 219         .cpu_die        = cpu_psci_cpu_die,
 220         .cpu_kill       = cpu_psci_cpu_kill,
 221 #endif
 222 };
 223