arch/arm/mach-vexpress/platsmp.c

   1 /*
   2  *  linux/arch/arm/mach-vexpress/platsmp.c
   3  *
   4  *  Copyright (C) 2002 ARM Ltd.
   5  *  All Rights Reserved
   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 #include <linux/init.h>
  12 #include <linux/errno.h>
  13 #include <linux/smp.h>
  14 #include <linux/io.h>
  15 #include <linux/of_address.h>
  16 #include <linux/vexpress.h>
  17
  18 #include <asm/mcpm.h>
  19 #include <asm/smp_scu.h>
  20 #include <asm/mach/map.h>
  21
  22 #include <plat/platsmp.h>
  23
  24 #include "core.h"
  25
  26 bool __init vexpress_smp_init_ops(void)
  27 {
  28 #ifdef CONFIG_MCPM
  29         int cpu;
  30         struct device_node *cpu_node, *cci_node;
  31
  32         /*
  33          * The best way to detect a multi-cluster configuration
  34          * is to detect if the kernel can take over CCI ports
  35          * control. Loop over possible CPUs and check if CCI
  36          * port control is available.
  37          * Override the default vexpress_smp_ops if so.
  38          */
  39         for_each_possible_cpu(cpu) {
  40                 bool available;
  41
  42                 cpu_node = of_get_cpu_node(cpu, NULL);
  43                 if (WARN(!cpu_node, "Missing cpu device node!"))
  44                         return false;
  45
  46                 cci_node = of_parse_phandle(cpu_node, "cci-control-port", 0);
  47                 available = cci_node && of_device_is_available(cci_node);
  48                 of_node_put(cci_node);
  49                 of_node_put(cpu_node);
  50
  51                 if (!available)
  52                         return false;
  53         }
  54
  55         mcpm_smp_set_ops();
  56         return true;
  57 #else
  58         return false;
  59 #endif
  60 }
  61
  62 static const struct of_device_id vexpress_smp_dt_scu_match[] __initconst = {
  63         { .compatible = "arm,cortex-a5-scu", },
  64         { .compatible = "arm,cortex-a9-scu", },
  65         {}
  66 };
  67
  68 static void __init vexpress_smp_dt_prepare_cpus(unsigned int max_cpus)
  69 {
  70         struct device_node *scu = of_find_matching_node(NULL,
  71                         vexpress_smp_dt_scu_match);
  72
  73         if (scu)
  74                 scu_enable(of_iomap(scu, 0));
  75
  76         /*
  77          * Write the address of secondary startup into the
  78          * system-wide flags register. The boot monitor waits
  79          * until it receives a soft interrupt, and then the
  80          * secondary CPU branches to this address.
  81          */
  82         vexpress_flags_set(__pa_symbol(versatile_secondary_startup));
  83 }
  84
  85 #ifdef CONFIG_HOTPLUG_CPU
  86 static void vexpress_cpu_die(unsigned int cpu)
  87 {
  88         versatile_immitation_cpu_die(cpu, 0x40);
  89 }
  90 #endif
  91
  92 const struct smp_operations vexpress_smp_dt_ops __initconst = {
  93         .smp_prepare_cpus       = vexpress_smp_dt_prepare_cpus,
  94         .smp_secondary_init     = versatile_secondary_init,
  95         .smp_boot_secondary     = versatile_boot_secondary,
  96 #ifdef CONFIG_HOTPLUG_CPU
  97         .cpu_die                = vexpress_cpu_die,
  98 #endif
  99 };