arch/arm/mach-vexpress/platsmp.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/mach-vexpress/platsmp.c
   4  *
   5  *  Copyright (C) 2002 ARM Ltd.
   6  *  All Rights Reserved
   7  */
   8 #include <linux/init.h>
   9 #include <linux/errno.h>
  10 #include <linux/smp.h>
  11 #include <linux/io.h>
  12 #include <linux/of_address.h>
  13 #include <linux/vexpress.h>
  14
  15 #include <asm/mcpm.h>
  16 #include <asm/smp_scu.h>
  17 #include <asm/mach/map.h>
  18
  19 #include <plat/platsmp.h>
  20
  21 #include "core.h"
  22
  23 bool __init vexpress_smp_init_ops(void)
  24 {
  25 #ifdef CONFIG_MCPM
  26         int cpu;
  27         struct device_node *cpu_node, *cci_node;
  28
  29         /*
  30          * The best way to detect a multi-cluster configuration
  31          * is to detect if the kernel can take over CCI ports
  32          * control. Loop over possible CPUs and check if CCI
  33          * port control is available.
  34          * Override the default vexpress_smp_ops if so.
  35          */
  36         for_each_possible_cpu(cpu) {
  37                 bool available;
  38
  39                 cpu_node = of_get_cpu_node(cpu, NULL);
  40                 if (WARN(!cpu_node, "Missing cpu device node!"))
  41                         return false;
  42
  43                 cci_node = of_parse_phandle(cpu_node, "cci-control-port", 0);
  44                 available = cci_node && of_device_is_available(cci_node);
  45                 of_node_put(cci_node);
  46                 of_node_put(cpu_node);
  47
  48                 if (!available)
  49                         return false;
  50         }
  51
  52         mcpm_smp_set_ops();
  53         return true;
  54 #else
  55         return false;
  56 #endif
  57 }
  58
  59 static const struct of_device_id vexpress_smp_dt_scu_match[] __initconst = {
  60         { .compatible = "arm,cortex-a5-scu", },
  61         { .compatible = "arm,cortex-a9-scu", },
  62         {}
  63 };
  64
  65 static void __init vexpress_smp_dt_prepare_cpus(unsigned int max_cpus)
  66 {
  67         struct device_node *scu = of_find_matching_node(NULL,
  68                         vexpress_smp_dt_scu_match);
  69
  70         if (scu)
  71                 scu_enable(of_iomap(scu, 0));
  72
  73         /*
  74          * Write the address of secondary startup into the
  75          * system-wide flags register. The boot monitor waits
  76          * until it receives a soft interrupt, and then the
  77          * secondary CPU branches to this address.
  78          */
  79         vexpress_flags_set(__pa_symbol(versatile_secondary_startup));
  80 }
  81
  82 #ifdef CONFIG_HOTPLUG_CPU
  83 static void vexpress_cpu_die(unsigned int cpu)
  84 {
  85         versatile_immitation_cpu_die(cpu, 0x40);
  86 }
  87 #endif
  88
  89 const struct smp_operations vexpress_smp_dt_ops __initconst = {
  90         .smp_prepare_cpus       = vexpress_smp_dt_prepare_cpus,
  91         .smp_secondary_init     = versatile_secondary_init,
  92         .smp_boot_secondary     = versatile_boot_secondary,
  93 #ifdef CONFIG_HOTPLUG_CPU
  94         .cpu_die                = vexpress_cpu_die,
  95 #endif
  96 };