arch/arm/mach-versatile/platsmp-vexpress.c

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