arch/arm/mach-mvebu/platsmp-a9.c

   1 /*
   2  * Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9
   3  * based SOCs (Armada 375/38x).
   4  *
   5  * Copyright (C) 2014 Marvell
   6  *
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   9  *
  10  * This file is licensed under the terms of the GNU General Public
  11  * License version 2.  This program is licensed "as is" without any
  12  * warranty of any kind, whether express or implied.
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/of.h>
  18 #include <linux/smp.h>
  19 #include <linux/mbus.h>
  20 #include <asm/smp_scu.h>
  21 #include <asm/smp_plat.h>
  22 #include "common.h"
  23 #include "pmsu.h"
  24
  25 extern void mvebu_cortex_a9_secondary_startup(void);
  26
  27 static int mvebu_cortex_a9_boot_secondary(unsigned int cpu,
  28                                                     struct task_struct *idle)
  29 {
  30         int ret, hw_cpu;
  31
  32         pr_info("Booting CPU %d\n", cpu);
  33
  34         /*
  35          * Write the address of secondary startup into the system-wide
  36          * flags register. The boot monitor waits until it receives a
  37          * soft interrupt, and then the secondary CPU branches to this
  38          * address.
  39          */
  40         hw_cpu = cpu_logical_map(cpu);
  41         if (of_machine_is_compatible("marvell,armada375"))
  42                 mvebu_system_controller_set_cpu_boot_addr(mvebu_cortex_a9_secondary_startup);
  43         else
  44                 mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cortex_a9_secondary_startup);
  45         smp_wmb();
  46
  47         /*
  48          * Doing this before deasserting the CPUs is needed to wake up CPUs
  49          * in the offline state after using CPU hotplug.
  50          */
  51         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  52
  53         ret = mvebu_cpu_reset_deassert(hw_cpu);
  54         if (ret) {
  55                 pr_err("Could not start the secondary CPU: %d\n", ret);
  56                 return ret;
  57         }
  58
  59         return 0;
  60 }
  61 /*
  62  * When a CPU is brought back online, either through CPU hotplug, or
  63  * because of the boot of a kexec'ed kernel, the PMSU configuration
  64  * for this CPU might be in the deep idle state, preventing this CPU
  65  * from receiving interrupts. Here, we therefore take out the current
  66  * CPU from this state, which was entered by armada_38x_cpu_die()
  67  * below.
  68  */
  69 static void armada_38x_secondary_init(unsigned int cpu)
  70 {
  71         mvebu_v7_pmsu_idle_exit();
  72 }
  73
  74 #ifdef CONFIG_HOTPLUG_CPU
  75 static void armada_38x_cpu_die(unsigned int cpu)
  76 {
  77         /*
  78          * CPU hotplug is implemented by putting offline CPUs into the
  79          * deep idle sleep state.
  80          */
  81         armada_38x_do_cpu_suspend(true);
  82 }
  83
  84 /*
  85  * We need a dummy function, so that platform_can_cpu_hotplug() knows
  86  * we support CPU hotplug. However, the function does not need to do
  87  * anything, because CPUs going offline can enter the deep idle state
  88  * by themselves, without any help from a still alive CPU.
  89  */
  90 static int armada_38x_cpu_kill(unsigned int cpu)
  91 {
  92         return 1;
  93 }
  94 #endif
  95
  96 static const struct smp_operations mvebu_cortex_a9_smp_ops __initconst = {
  97         .smp_boot_secondary     = mvebu_cortex_a9_boot_secondary,
  98 };
  99
 100 static const struct smp_operations armada_38x_smp_ops __initconst = {
 101         .smp_boot_secondary     = mvebu_cortex_a9_boot_secondary,
 102         .smp_secondary_init     = armada_38x_secondary_init,
 103 #ifdef CONFIG_HOTPLUG_CPU
 104         .cpu_die                = armada_38x_cpu_die,
 105         .cpu_kill               = armada_38x_cpu_kill,
 106 #endif
 107 };
 108
 109 CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",
 110                       &mvebu_cortex_a9_smp_ops);
 111 CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",
 112                       &armada_38x_smp_ops);
 113 CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",
 114                       &armada_38x_smp_ops);