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 bool psci_power_state_loses_context(u32 state)
  34 {
  35         return state & PSCI_0_2_POWER_STATE_TYPE_MASK;
  36 }
  37
  38 static bool psci_power_state_is_valid(u32 state)
  39 {
  40         const u32 valid_mask = PSCI_0_2_POWER_STATE_ID_MASK |
  41                                PSCI_0_2_POWER_STATE_TYPE_MASK |
  42                                PSCI_0_2_POWER_STATE_AFFL_MASK;
  43
  44         return !(state & ~valid_mask);
  45 }
  46
  47 static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
  48
  49 static int __maybe_unused cpu_psci_cpu_init_idle(unsigned int cpu)
  50 {
  51         int i, ret, count = 0;
  52         u32 *psci_states;
  53         struct device_node *state_node, *cpu_node;
  54
  55         cpu_node = of_get_cpu_node(cpu, NULL);
  56         if (!cpu_node)
  57                 return -ENODEV;
  58
  59         /*
  60          * If the PSCI cpu_suspend function hook has not been initialized
  61          * idle states must not be enabled, so bail out
  62          */
  63         if (!psci_ops.cpu_suspend)
  64                 return -EOPNOTSUPP;
  65
  66         /* Count idle states */
  67         while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
  68                                               count))) {
  69                 count++;
  70                 of_node_put(state_node);
  71         }
  72
  73         if (!count)
  74                 return -ENODEV;
  75
  76         psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
  77         if (!psci_states)
  78                 return -ENOMEM;
  79
  80         for (i = 0; i < count; i++) {
  81                 u32 state;
  82
  83                 state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
  84
  85                 ret = of_property_read_u32(state_node,
  86                                            "arm,psci-suspend-param",
  87                                            &state);
  88                 if (ret) {
  89                         pr_warn(" * %s missing arm,psci-suspend-param property\n",
  90                                 state_node->full_name);
  91                         of_node_put(state_node);
  92                         goto free_mem;
  93                 }
  94
  95                 of_node_put(state_node);
  96                 pr_debug("psci-power-state %#x index %d\n", state, i);
  97                 if (!psci_power_state_is_valid(state)) {
  98                         pr_warn("Invalid PSCI power state %#x\n", state);
  99                         ret = -EINVAL;
 100                         goto free_mem;
 101                 }
 102                 psci_states[i] = state;
 103         }
 104         /* Idle states parsed correctly, initialize per-cpu pointer */
 105         per_cpu(psci_power_state, cpu) = psci_states;
 106         return 0;
 107
 108 free_mem:
 109         kfree(psci_states);
 110         return ret;
 111 }
 112
 113 static int __init cpu_psci_cpu_init(unsigned int cpu)
 114 {
 115         return 0;
 116 }
 117
 118 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 119 {
 120         if (!psci_ops.cpu_on) {
 121                 pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 122                 return -ENODEV;
 123         }
 124
 125         return 0;
 126 }
 127
 128 static int cpu_psci_cpu_boot(unsigned int cpu)
 129 {
 130         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 131         if (err)
 132                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 133
 134         return err;
 135 }
 136
 137 #ifdef CONFIG_HOTPLUG_CPU
 138 static int cpu_psci_cpu_disable(unsigned int cpu)
 139 {
 140         /* Fail early if we don't have CPU_OFF support */
 141         if (!psci_ops.cpu_off)
 142                 return -EOPNOTSUPP;
 143
 144         /* Trusted OS will deny CPU_OFF */
 145         if (psci_tos_resident_on(cpu))
 146                 return -EPERM;
 147
 148         return 0;
 149 }
 150
 151 static void cpu_psci_cpu_die(unsigned int cpu)
 152 {
 153         int ret;
 154         /*
 155          * There are no known implementations of PSCI actually using the
 156          * power state field, pass a sensible default for now.
 157          */
 158         u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
 159                     PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 160
 161         ret = psci_ops.cpu_off(state);
 162
 163         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 164 }
 165
 166 static int cpu_psci_cpu_kill(unsigned int cpu)
 167 {
 168         int err, i;
 169
 170         if (!psci_ops.affinity_info)
 171                 return 0;
 172         /*
 173          * cpu_kill could race with cpu_die and we can
 174          * potentially end up declaring this cpu undead
 175          * while it is dying. So, try again a few times.
 176          */
 177
 178         for (i = 0; i < 10; i++) {
 179                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 180                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 181                         pr_info("CPU%d killed.\n", cpu);
 182                         return 0;
 183                 }
 184
 185                 msleep(10);
 186                 pr_info("Retrying again to check for CPU kill\n");
 187         }
 188
 189         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 190                         cpu, err);
 191         return -ETIMEDOUT;
 192 }
 193 #endif
 194
 195 static int psci_suspend_finisher(unsigned long index)
 196 {
 197         u32 *state = __this_cpu_read(psci_power_state);
 198
 199         return psci_ops.cpu_suspend(state[index - 1],
 200                                     virt_to_phys(cpu_resume));
 201 }
 202
 203 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
 204 {
 205         int ret;
 206         u32 *state = __this_cpu_read(psci_power_state);
 207         /*
 208          * idle state index 0 corresponds to wfi, should never be called
 209          * from the cpu_suspend operations
 210          */
 211         if (WARN_ON_ONCE(!index))
 212                 return -EINVAL;
 213
 214         if (!psci_power_state_loses_context(state[index - 1]))
 215                 ret = psci_ops.cpu_suspend(state[index - 1], 0);
 216         else
 217                 ret = cpu_suspend(index, psci_suspend_finisher);
 218
 219         return ret;
 220 }
 221
 222 const struct cpu_operations cpu_psci_ops = {
 223         .name           = "psci",
 224 #ifdef CONFIG_CPU_IDLE
 225         .cpu_init_idle  = cpu_psci_cpu_init_idle,
 226         .cpu_suspend    = cpu_psci_cpu_suspend,
 227 #endif
 228         .cpu_init       = cpu_psci_cpu_init,
 229         .cpu_prepare    = cpu_psci_cpu_prepare,
 230         .cpu_boot       = cpu_psci_cpu_boot,
 231 #ifdef CONFIG_HOTPLUG_CPU
 232         .cpu_disable    = cpu_psci_cpu_disable,
 233         .cpu_die        = cpu_psci_cpu_die,
 234         .cpu_kill       = cpu_psci_cpu_kill,
 235 #endif
 236 };
 237