arch/arm/common/mcpm_platsmp.c

   1 /*
   2  * linux/arch/arm/mach-vexpress/mcpm_platsmp.c
   3  *
   4  * Created by:  Nicolas Pitre, November 2012
   5  * Copyright:   (C) 2012-2013  Linaro Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Code to handle secondary CPU bringup and hotplug for the cluster power API.
  12  */
  13
  14 #include <linux/init.h>
  15 #include <linux/smp.h>
  16 #include <linux/spinlock.h>
  17
  18 #include <asm/mcpm.h>
  19 #include <asm/smp.h>
  20 #include <asm/smp_plat.h>
  21
  22 static void cpu_to_pcpu(unsigned int cpu,
  23                         unsigned int *pcpu, unsigned int *pcluster)
  24 {
  25         unsigned int mpidr;
  26
  27         mpidr = cpu_logical_map(cpu);
  28         *pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
  29         *pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
  30 }
  31
  32 static int mcpm_boot_secondary(unsigned int cpu, struct task_struct *idle)
  33 {
  34         unsigned int pcpu, pcluster, ret;
  35         extern void secondary_startup(void);
  36
  37         cpu_to_pcpu(cpu, &pcpu, &pcluster);
  38
  39         pr_debug("%s: logical CPU %d is physical CPU %d cluster %d\n",
  40                  __func__, cpu, pcpu, pcluster);
  41
  42         mcpm_set_entry_vector(pcpu, pcluster, NULL);
  43         ret = mcpm_cpu_power_up(pcpu, pcluster);
  44         if (ret)
  45                 return ret;
  46         mcpm_set_entry_vector(pcpu, pcluster, secondary_startup);
  47         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  48         dsb_sev();
  49         return 0;
  50 }
  51
  52 static void mcpm_secondary_init(unsigned int cpu)
  53 {
  54         mcpm_cpu_powered_up();
  55 }
  56
  57 #ifdef CONFIG_HOTPLUG_CPU
  58
  59 static int mcpm_cpu_kill(unsigned int cpu)
  60 {
  61         unsigned int pcpu, pcluster;
  62
  63         cpu_to_pcpu(cpu, &pcpu, &pcluster);
  64
  65         return !mcpm_wait_for_cpu_powerdown(pcpu, pcluster);
  66 }
  67
  68 static bool mcpm_cpu_can_disable(unsigned int cpu)
  69 {
  70         /* We assume all CPUs may be shut down. */
  71         return true;
  72 }
  73
  74 static void mcpm_cpu_die(unsigned int cpu)
  75 {
  76         unsigned int mpidr, pcpu, pcluster;
  77         mpidr = read_cpuid_mpidr();
  78         pcpu = MPIDR_AFFINITY_LEVEL(mpidr, 0);
  79         pcluster = MPIDR_AFFINITY_LEVEL(mpidr, 1);
  80         mcpm_set_entry_vector(pcpu, pcluster, NULL);
  81         mcpm_cpu_power_down();
  82 }
  83
  84 #endif
  85
  86 static const struct smp_operations mcpm_smp_ops __initconst = {
  87         .smp_boot_secondary     = mcpm_boot_secondary,
  88         .smp_secondary_init     = mcpm_secondary_init,
  89 #ifdef CONFIG_HOTPLUG_CPU
  90         .cpu_kill               = mcpm_cpu_kill,
  91         .cpu_can_disable        = mcpm_cpu_can_disable,
  92         .cpu_die                = mcpm_cpu_die,
  93 #endif
  94 };
  95
  96 void __init mcpm_smp_set_ops(void)
  97 {
  98         smp_set_ops(&mcpm_smp_ops);
  99 }