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