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 #include <linux/delay.h>
  20 #include <uapi/linux/psci.h>
  21
  22 #include <asm/psci.h>
  23 #include <asm/smp_plat.h>
  24
  25 /*
  26  * psci_smp assumes that the following is true about PSCI:
  27  *
  28  * cpu_suspend   Suspend the execution on a CPU
  29  * @state        we don't currently describe affinity levels, so just pass 0.
  30  * @entry_point  the first instruction to be executed on return
  31  * returns 0  success, < 0 on failure
  32  *
  33  * cpu_off       Power down a CPU
  34  * @state        we don't currently describe affinity levels, so just pass 0.
  35  * no return on successful call
  36  *
  37  * cpu_on        Power up a CPU
  38  * @cpuid        cpuid of target CPU, as from MPIDR
  39  * @entry_point  the first instruction to be executed on return
  40  * returns 0  success, < 0 on failure
  41  *
  42  * migrate       Migrate the context to a different CPU
  43  * @cpuid        cpuid of target CPU, as from MPIDR
  44  * returns 0  success, < 0 on failure
  45  *
  46  */
  47
  48 extern void secondary_startup(void);
  49
  50 extern void __init mt_smp_prepare_cpus(unsigned int max_cpus);
  51 extern void mt_smp_secondary_init(unsigned int cpu);
  52 extern int mt_smp_boot_secondary(unsigned int cpu, struct task_struct *idle);
  53 extern int mt_cpu_kill(unsigned int cpu);
  54
  55 static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
  56 {
  57         int ret = -1;
  58
  59         if (psci_ops.cpu_on)
  60                 ret = psci_ops.cpu_on(cpu_logical_map(cpu),
  61                                        __pa(secondary_startup));
  62
  63         if (ret < 0) {
  64                 pr_err("psci cpu_on failed\n");
  65                 return -ENODEV;
  66         }
  67
  68         ret = mt_smp_boot_secondary(cpu, idle);
  69         if (ret < 0) {
  70                 pr_err("mt_smp_boot_secondary failed\n");
  71                 return -ENODEV;
  72         }
  73         return 0;
  74 }
  75
  76 #ifdef CONFIG_HOTPLUG_CPU
  77 void __ref psci_cpu_die(unsigned int cpu)
  78 {
  79         const struct psci_power_state ps = {
  80                  .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
  81         };
  82
  83         if (psci_ops.cpu_off)
  84                  psci_ops.cpu_off(ps);
  85
  86         /* We should never return */
  87         panic("psci: cpu %d failed to shutdown\n", cpu);
  88 }
  89
  90 int __ref psci_cpu_kill(unsigned int cpu)
  91 {
  92         //TODO: do more accurate synchornization between src CPU and dst CPU when applying psci
  93         //int err, i;
  94         //
  95         //if (!psci_ops.affinity_info)
  96         //      return 1;
  97         ///*
  98         // * cpu_kill could race with cpu_die and we can
  99         // * potentially end up declaring this cpu undead
 100         // * while it is dying. So, try again a few times.
 101         // */
 102         //
 103         //for (i = 0; i < 10; i++) {
 104         //      err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 105         //      if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 106         //              pr_info("CPU%d killed.\n", cpu);
 107         //              return 1;
 108         //      }
 109         //
 110         //      msleep(10);
 111         //      pr_info("Retrying again to check for CPU kill\n");
 112         //}
 113         //
 114         //pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 115         //              cpu, err);
 116         ///* Make platform_cpu_kill() fail. */
 117         //return 0;
 118         return mt_cpu_kill(cpu);
 119 }
 120
 121 #endif
 122
 123 bool __init psci_smp_available(void)
 124 {
 125         /* is cpu_on available at least? */
 126         return (psci_ops.cpu_on != NULL);
 127 }
 128
 129 struct smp_operations __initdata psci_smp_ops = {
 130         .smp_prepare_cpus       = mt_smp_prepare_cpus,
 131         .smp_boot_secondary         = psci_boot_secondary,
 132         // FIXME: better way?
 133         .smp_secondary_init     = mt_smp_secondary_init,
 134 #ifdef CONFIG_HOTPLUG_CPU
 135         .cpu_die                        = psci_cpu_die,
 136         .cpu_kill                       = psci_cpu_kill,
 137 #endif
 138 };