arch/arm/kernel/psci_smp.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) 2012 ARM Limited
  12  *
  13  * Author: Will Deacon <will.deacon@arm.com>
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/irqchip/arm-gic.h>
  18 #include <linux/smp.h>
  19 #include <linux/of.h>
  20
  21 #include <asm/psci.h>
  22 #include <asm/smp_plat.h>
  23
  24 /*
  25  * psci_smp assumes that the following is true about PSCI:
  26  *
  27  * cpu_suspend   Suspend the execution on a CPU
  28  * @state        we don't currently describe affinity levels, so just pass 0.
  29  * @entry_point  the first instruction to be executed on return
  30  * returns 0  success, < 0 on failure
  31  *
  32  * cpu_off       Power down a CPU
  33  * @state        we don't currently describe affinity levels, so just pass 0.
  34  * no return on successful call
  35  *
  36  * cpu_on        Power up a CPU
  37  * @cpuid        cpuid of target CPU, as from MPIDR
  38  * @entry_point  the first instruction to be executed on return
  39  * returns 0  success, < 0 on failure
  40  *
  41  * migrate       Migrate the context to a different CPU
  42  * @cpuid        cpuid of target CPU, as from MPIDR
  43  * returns 0  success, < 0 on failure
  44  *
  45  */
  46
  47 extern void secondary_startup(void);
  48
  49 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
  50 {
  51         if (psci_ops.cpu_on)
  52                 return psci_ops.cpu_on(cpu_logical_map(cpu),
  53                                        __pa(secondary_startup));
  54         return -ENODEV;
  55 }
  56
  57 #ifdef CONFIG_HOTPLUG_CPU
  58 void __ref psci_cpu_die(unsigned int cpu)
  59 {
  60        const struct psci_power_state ps = {
  61                .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
  62        };
  63
  64        if (psci_ops.cpu_off)
  65                psci_ops.cpu_off(ps);
  66
  67        /* We should never return */
  68        panic("psci: cpu %d failed to shutdown\n", cpu);
  69 }
  70 #endif
  71
  72 bool __init psci_smp_available(void)
  73 {
  74         /* is cpu_on available at least? */
  75         return (psci_ops.cpu_on != NULL);
  76 }
  77
  78 struct smp_operations __initdata psci_smp_ops = {
  79         .smp_boot_secondary     = psci_boot_secondary,
  80 #ifdef CONFIG_HOTPLUG_CPU
  81         .cpu_die                = psci_cpu_die,
  82 #endif
  83 };